1. A method for manufacturing a base material for a metal mask, comprising:

preparing a metal rolled sheet having a front surface and a back surface that is a surface opposite to the front surface, at least one of the front surface and the back surface being a processing target; and

a step of obtaining a metal mask sheet by etching the object to be processed by an acidic etching solution to a thickness of 3 μm or more, thereby reducing the thickness of the metal rolled sheet to 10 μm or less, and roughening the object to be processed to a processed surface for resist having a surface roughness Rz of 0.2 μm or more,

the metal rolled sheet contains particles made of a metal oxide.

2. The method for manufacturing a substrate for a metal mask according to claim 1, wherein,

the processing objects are both the front surface and the back surface.

3. The method for manufacturing a substrate for a metal mask according to claim 1, wherein,

the object to be processed is either the front surface or the back surface,

the manufacturing method further includes a step of laminating a support layer made of resin on a surface opposite to the processing object,

the metal mask sheet is laminated on the support layer by etching the object to be processed in a state where the metal rolled sheet and the support layer are laminated, thereby obtaining a metal mask base material in which the metal mask sheet and the support layer are laminated.

4. The method for manufacturing a substrate for a metal mask according to claim 2, wherein,

the etching step includes: etching a first processing object which is one of the front surface and the back surface; and then etching the second processing object which is the other of the front surface and the back surface,

the manufacturing method further includes a step of laminating a support layer made of a resin on the resist processing surface obtained by etching the first processing object after etching the first processing object,

the second processing object is etched in a state where the metal rolled sheet and the support layer are laminated, thereby obtaining a metal mask base material in which the metal mask sheet and the support layer are laminated.

5. The method for manufacturing a substrate for a metal mask according to claim 1, wherein,

the metal rolled sheet has a thickness of 10 to 100 [ mu ] m,

in the metal rolled sheet, a portion other than the particles contains a metal different from a metal contained in the particles,

in the rolled metal sheet, a portion including a center in a thickness direction of the rolled metal sheet is a center portion, a portion including the front surface is a 1 st surface layer portion, a portion including the back surface is a 2 nd surface layer portion,

the particles are distributed more in the 1 st surface layer part and the 2 nd surface layer part than in the central part.

6. The method for manufacturing a substrate for a metal mask according to claim 1, wherein,

the resist processing surface has particle marks each having a plurality of elliptical-hammer-shaped recesses, and the particle marks are aligned in the longitudinal direction.

7. The method for manufacturing a substrate for a metal mask according to claim 3, wherein,

the coefficient of thermal expansion of the metal rolled sheet is about the same as the coefficient of thermal expansion of the resin support layer.

8. The method for manufacturing a substrate for a metal mask according to claim 7, wherein,

the metal rolling sheet is an invar alloy rolling sheet,

the metal mask sheet is made of invar alloy,

the support layer made of resin is made of polyimide.

9. The method for manufacturing a substrate for a metal mask according to claim 1 or 2, wherein,

the metal rolling sheet is an invar alloy rolling sheet,

the metal mask sheet is made of invar alloy.

10. A method for manufacturing a metal mask for vapor deposition, comprising the steps of:

forming a metal mask base material having at least one resist-treated surface;

forming a resist layer on one of the resist processing surfaces;

forming a resist mask by patterning the resist layer; and

etching the metal mask base material using the resist mask,

the method for manufacturing a metal mask for vapor deposition is a method for manufacturing a metal mask substrate according to any one of claims 1 to 9.

11. A method for manufacturing a metal mask for vapor deposition according to claim 10, wherein the metal mask for vapor deposition is formed by a sputtering method,

the metal mask base material comprises a laminate of the metal mask sheet and a resin support layer,

the method for producing a vapor deposition metal mask may further include a step of exposing the metal mask substrate after the resist mask is formed to an alkaline solution to chemically remove the support layer from the metal mask substrate.

12. A base material for a metal mask, wherein,

comprises a metal sheet having a front surface and a back surface opposite to the front surface,

at least one of the front surface and the back surface is a resist-treated surface,

the metal sheet has a thickness of 10 μm or less,

the surface roughness Rz of the treated surface for the resist is 0.2 μm or more,

comprising particles composed of a metal oxide.

13. The substrate for metal masks according to claim 12,

the resist processing surface has particle marks each having a plurality of elliptical-hammer-shaped recesses, and the particle marks are aligned in the longitudinal direction.

14. A metal mask for vapor deposition, wherein,

comprises a base material for a metal mask and a metal layer,

the metal mask substrate according to claim 12 or 13,

the metal sheet included in the metal mask base material has a plurality of through holes that penetrate between the front surface and the back surface.

Background

As one of display devices manufactured by using a vapor deposition method, an organic EL display is known. The organic layer included in the organic EL display is a deposit of organic molecules sublimated in the vapor deposition step. The openings of the metal mask used in the vapor deposition step are passages through which the sublimated organic molecules pass, and have a shape corresponding to the shape of the pixels of the organic EL display (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2015-055007

Disclosure of Invention

Problems to be solved by the invention

However, as the display quality of the display device is improved and the display device is more highly refined, the organic EL display and further the metal mask having a predetermined pixel size are required to have a higher refinement in film formation using the metal mask. In recent years, high miniaturization of 700ppi or more is desired for an organic EL display, and thus a metal mask capable of forming an organic layer in such a high-definition organic EL display is expected.

Further, the high definition of film formation using a metal mask is expected not only for the manufacture of display devices including organic EL displays, but also for the formation of wirings provided in various devices, vapor deposition using a metal mask for functional layers provided in various devices, and the like.

An object of the present invention is to provide a method for producing a metal mask substrate, a method for producing a metal mask for vapor deposition, a metal mask substrate, and a metal mask for vapor deposition, which can form a film using a metal mask for vapor deposition with high definition.

Means for solving the problems

The method for manufacturing a base material for a metal mask for solving the above problems includes the steps of: preparing a metal rolled sheet having a front surface and a back surface that is a surface opposite to the front surface, at least one of the front surface and the back surface being a processing target; and etching the object to be processed by an acidic etching solution by 3 μm or more to reduce the thickness of the rolled metal sheet to 10 μm or less and roughen the object to be processed to a processed surface for a resist having a surface roughness Rz of 0.2 μm or more, thereby obtaining a metal mask sheet.

The method for manufacturing a metal mask for vapor deposition for solving the above problems includes the steps of: forming a metal mask base material having at least 1 resist processing surface; forming a resist layer on 1 of the resist treatment surfaces; forming a resist mask by patterning the resist layer; and etching the metal mask base material using the resist mask. The metal mask base material is formed by using the method for manufacturing a metal mask base material.

The metal mask base material for solving the above problems includes a metal sheet having a front surface and a back surface which is a surface opposite to the front surface, at least one of the front surface and the back surface is a treated surface for resist, the metal sheet has a thickness of 10 μm or less, and the treated surface for resist has a surface roughness Rz of 0.2 μm or more.

The metal mask for vapor deposition includes a metal mask base material, the metal mask base material being the metal mask base material, and the metal sheet included in the metal mask base material having a plurality of through holes penetrating between the front surface and the back surface.

According to the above configuration, since the thickness of the metal mask sheet is 10 μm or less, the depth of the mask opening formed in the metal mask sheet can be 10 μm or less. This can reduce the portion that becomes a shadow of the vapor deposition metal mask when the film formation object is viewed from the vapor deposition particles, i.e., can suppress the shadow effect, and therefore, the film formation object can be given a shape that follows the shape of the mask opening, and further, high definition of film formation using the vapor deposition metal mask can be achieved. In addition, when forming the mask opening in the metal mask sheet, first, when forming the resist layer on the resist-treated surface, the adhesion between the resist layer and the metal mask substrate can be improved compared to before roughening. In the formation of the mask opening, a reduction in shape accuracy due to the peeling of the resist layer from the metal mask sheet or the like can be suppressed, and therefore, in this regard, high definition of film formation using the metal mask for vapor deposition can also be achieved.

In the method of manufacturing a base material for a metal mask, the processing target may be both the front surface and the back surface.

According to the above configuration, the resist layer can be formed on any of the resist processing surfaces, regardless of whether the resist processing surface is formed on the front surface or the back surface. Therefore, it is possible to suppress difficulty in obtaining adhesion between the resist layer and the metal mask substrate due to mismatching of the surface on which the resist layer is to be formed, and further, it is possible to suppress a decrease in yield in the production of the metal mask for vapor deposition.

In the method of manufacturing a metal mask base material, the object to be processed may be either the front surface or the back surface, and the method may further include a step of laminating a support layer made of resin on a surface opposite to the object to be processed, and the object to be processed may be etched in a state where the rolled metal sheet and the support layer are laminated, thereby obtaining the metal mask base material in which the metal mask sheet and the support layer are laminated.

In the method for manufacturing a metal mask base material, the etching may include: etching a first processing object which is one of the front surface and the back surface; and etching a second object to be processed, which is the other of the front surface and the back surface, wherein the manufacturing method further comprises a step of laminating a support layer made of a resin on the resist processing surface obtained by the etching of the first object after the etching of the first object to be processed, and the second object to be processed is etched in a state where the metal rolled sheet and the support layer are laminated, thereby obtaining a metal mask base material in which the metal mask sheet and the support layer are laminated.

According to the above configuration, in the transportation of the metal mask sheet and the post-processing of the metal mask sheet, the trouble of processing the metal mask sheet due to the fragility of the metal mask sheet caused by the thickness of the metal mask sheet being 10 μm or less can be reduced.

In the method for producing a metal mask base material, the metal rolled sheet is preferably an invar alloy rolled sheet, and the metal mask sheet is preferably an invar alloy rolled sheet.

According to the above configuration, when the object to be film-formed is a glass substrate, the coefficient of linear expansion of the glass substrate is approximately the same as the coefficient of linear expansion of the invar alloy, and therefore, a metal mask made of a metal mask base material can be used for film formation on the glass substrate, that is, a metal mask with improved shape accuracy can be used for film formation on the glass substrate.

In the method for producing a vapor deposition metal mask, it is preferable that the metal mask base material includes a laminate of the metal mask sheet and a support layer made of a resin, and the method further includes: and exposing the metal mask base material after the resist mask is formed to an alkaline solution, thereby chemically removing the support layer from the metal mask base material.

According to the above configuration, as compared with the case where the support layer is physically peeled off from the metal mask sheet, no external force acts on the metal mask sheet, and therefore wrinkles and deformation of the metal mask sheet can be suppressed.

In the metal mask base material, the resist-treated surface may have particle marks as a plurality of recesses having an elliptical hammer shape, and the particle marks may be aligned in the longitudinal direction.

Since the metal sheet is usually produced by rolling, particles of an oxide or the like of the deoxidizer added in the production process of the metal sheet are not rarely mixed into the metal sheet. The particles mixed into the surface of the metal piece are elongated in the rolling direction of the metal material and have an elliptical hammer shape having a major diameter in the rolling direction. If such particles remain in the portions of the resist processing surface where the mask openings are formed, there is a possibility that etching for forming the mask openings is hindered by the particles.

In this regard, according to the above configuration, since the resist processing surface has a plurality of elliptical-hammer-shaped particle traces aligned in the major axis direction, that is, since the particles have been removed from the resist processing surface, it is possible to improve the accuracy of the shape and size of the mask opening at the time of forming the mask opening.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to improve the definition of a film formed using a metal mask for vapor deposition.

Drawings

Fig. 1 is a perspective view showing a three-dimensional structure of a metal mask base material according to 1 embodiment of the present invention.

Fig. 2 is a process diagram showing a step of preparing an invar alloy rolled sheet in the method for manufacturing a metal mask for vapor deposition.

Fig. 3 is a process diagram showing a step of etching the back surface of an invar rolled sheet in the method for manufacturing a metal mask for vapor deposition.

Fig. 4 is a process diagram showing a step of forming a support layer on a resist processing surface of an invar rolled sheet in a method of manufacturing a metal mask for vapor deposition.

Fig. 5 is a process diagram showing a step of etching the surface of an invar rolled sheet in the method for producing a metal mask for vapor deposition.

Fig. 6 is a schematic view schematically showing the distribution of metal oxides in an invar rolled sheet.

Fig. 7 is a process diagram showing a step of forming a resist layer in the method of manufacturing a metal mask for vapor deposition.

Fig. 8 is a process diagram showing a step of forming a resist mask in the method of manufacturing a metal mask for vapor deposition.

Fig. 9 is a process diagram showing a step of etching an invar sheet in the method for manufacturing a metal mask for vapor deposition.

Fig. 10 is a cross-sectional view showing a cross-sectional shape of a through hole formed by etching both the front surface and the back surface of the invar sheet.

Fig. 11 is a process diagram showing a step of removing a resist mask in a method of manufacturing a metal mask for vapor deposition.

Fig. 12 is a process diagram showing a step of chemically removing the support layer in the method for producing a metal mask for vapor deposition.

Fig. 13 is a sectional view showing a sectional structure of a vapor deposition metal mask attached to a frame.

Fig. 14 is a plan view showing a planar structure of a vapor deposition metal mask attached to a frame.

Fig. 15 is an SEM image obtained by photographing the surface of the invar rolled sheet of test example 1.

Fig. 16 is an SEM image obtained by photographing the processed surface for resist of the invar alloy sheet of test example 2.

Fig. 17 is an SEM image obtained by photographing the processed surface for resist of the invar alloy sheet of test example 3.

Fig. 18 is an SEM image obtained by photographing the processed surface for resist of the invar alloy sheet of test example 4.

Fig. 19 is an SEM image obtained by imaging the first particle trace.

Fig. 20 is an SEM image obtained by photographing the second particle trace.

Fig. 21 is a sectional view showing a sectional structure of a metal mask and a frame according to a modification.

Fig. 22 is a sectional view showing a sectional structure of a metal mask and a frame according to a modification.

Fig. 23 is a plan view showing a planar structure of an invar alloy sheet according to a modification.

Detailed Description

With reference to fig. 1 to 20, 1 embodiment of a method for manufacturing a metal mask substrate, a method for manufacturing a vapor deposition metal mask, a metal mask substrate, and a vapor deposition metal mask will be described. In the present embodiment, a metal mask for vapor deposition used for forming an organic layer included in an organic EL device will be described as an example of the metal mask for vapor deposition. Hereinafter, the configuration of the metal mask base material, the method for producing a metal mask for vapor deposition including the method for producing a metal mask base material, and the test examples will be described in order.

[ constitution of base Material for Metal mask ]

The structure of the metal mask base material will be described with reference to fig. 1.

As shown in fig. 1, the metal mask substrate 10 is an example of a metal mask sheet, and includes an invar sheet 11 which is a metal mask sheet made of invar, and the invar sheet 11 has a front surface 11a and a back surface 11b which is a surface opposite to the front surface 11 a. In the invar sheet 11, the front surface 11a and the back surface 11b are processed surfaces for resist, and are surfaces on which a resist layer can be formed when the invar sheet 11 is etched.

The invar alloy sheet 11 has a thickness T1 of 10 μm or less and a surface roughness Rz of the front surface 11a and a surface roughness Rz of the back surface 11b of 0.2 μm or less.

Since the invar alloy sheet 11 has a thickness of 10 μm or less, the depth of the mask opening formed in the invar alloy sheet 11 can be 10 μm or less. This can reduce a portion which becomes a shadow of the vapor deposition metal mask when the film formation target is viewed from the vapor deposition particles, that is, can suppress the shadow effect, and therefore, can form a film having a shape which follows the shape of the opening of the target mask, and can realize high definition of the film formation using the vapor deposition metal mask.

In addition, when forming the mask opening in the invar sheet 11, first, when forming the resist layer on the surface 11a, the adhesiveness between the resist layer and the invar sheet 11 can be improved more than before roughening. In addition, since the reduction in shape accuracy due to the resist layer being peeled off from the alloy sheet 11 or the like can be suppressed in the formation of the mask opening, high definition of film formation using the metal mask for vapor deposition can be achieved in this regard.

The invar alloy sheet 11 is made of a nickel-iron alloy containing 36 mass% of nickel and iron, i.e., an invar alloy, and the invar alloy, i.e., the invar alloy sheet 11, has a coefficient of thermal expansion of 1.2 × 10^-6Degree/° c.

The invar alloy sheet 11 has a thermal expansion coefficient approximately equal to that of a glass substrate, which is an example of a film formation target. Therefore, the metal mask for vapor deposition produced using the metal mask base material 10 can be applied to film formation on a glass substrate, that is, the metal mask for vapor deposition with improved shape accuracy can be applied to film formation on a glass substrate.

The surface roughness Rz of the surface of the invar alloy sheet 11 is a value measured by a method conforming to JISB 0601-2001. The surface roughness Rz is the maximum height in the profile curve with the reference length.

The metal mask base material 10 further includes a support layer 12 made of resin, and the metal mask base material 10 is a laminate of an invar alloy sheet 11 and the support layer 12. The back surface 11b of the invar alloy sheet 11 is in close contact with the support layer 12. The material for forming the support layer 12 is, for example, at least one of polyimide and negative resist. The support layer 12 may be 1 layer made of polyimide or 1 layer made of negative resist. Alternatively, the support layer 12 may be a laminate of a polyimide layer and a negative resist layer.

Among these, the thermal expansion coefficient of polyimide shows the same tendency as that of invar as temperature dependency, and the value of the thermal expansion coefficient is the same degree. Therefore, if the material for forming the support layer 12 is polyimide, the occurrence of warpage in the metal mask base material 10 and further in the invar sheet 11 due to a temperature change in the metal mask base material 10 can be suppressed, as compared with a configuration in which the support layer 12 is made of a resin other than polyimide.

[ method for producing Metal mask for vapor deposition ]

A method for manufacturing a metal mask for vapor deposition will be described with reference to fig. 2 to 12.

As shown in fig. 2, the method for manufacturing a metal mask for vapor deposition includes a method for manufacturing a metal mask base material 10, and in the method for manufacturing a metal mask base material 10, first, an invar rolled sheet 21, which is an example of a metal rolled sheet, is prepared. The invar alloy rolled sheet 21 includes a front surface 21a and a back surface 21b opposite to the front surface 21a, and the front surface 21a and the back surface 21b of the invar alloy rolled sheet 21 are targets to be processed in the method for manufacturing the metal mask base material 10.

The invar rolled sheet 21 is obtained by rolling an invar base material and annealing the rolled base material. Since the invar rolled sheet 21 is rolled, the surface roughness Rz of the front surface 21a and the back surface 21b of the invar rolled sheet 21 is smaller than the surface roughness Rz of the front surface and the back surface of the base material by the amount of the step difference on the front surface and the back surface of the base material.

The invar rolled sheet 21 has a thickness T2 of, for example, 10 to 100 μm, more preferably 10 to 50 μm.

As shown in fig. 3, the back surface 21b, which is an example of the first process object etched first out of 2 process objects, is etched by an acidic etching solution by 3 μm or more. The difference between the back surface 21b of invar rolled sheet 21 before etching and the back surface of invar rolled sheet 21 after etching, that is, processed surface 21c for resist is etching thickness T3, and etching thickness T3 is 3 μm or more.

By etching the back surface 21b, the thickness of the invar rolled sheet 21 can be made smaller than before etching, and the back surface 21b can be roughened so that the resist-treated surface 21c has a surface roughness Rz of 0.2 μm or more.

The acidic etching solution is an etching solution capable of etching invar, and may be a solution having a composition such that the back surface 21b of the invar rolled sheet 21 is rougher than before etching. The acidic etching solution is, for example, a solution obtained by mixing perchloric acid, hydrochloric acid, sulfuric acid, formic acid, or acetic acid with an iron perchlorate solution or a mixed solution of an iron perchlorate solution and an iron chloride solution. The etching of the back surface 21b may be a dipping type in which the invar rolled sheet 21 is dipped in an acidic etching solution, a spraying type in which an acidic etching solution is blown to the back surface 21b of the invar rolled sheet 21, or a rotating type in which an acidic etching solution is dropped onto the invar rolled sheet 21 rotated by a rotator.

The etching thickness T3 may be at least 3 μm, preferably 10 μm or more, and more preferably 15 μm or more.

As shown in fig. 4, after the back surface 21b of invar rolled sheet 21 is etched, the above-described support layer 12 made of resin is laminated on a processed surface 21c for resist obtained by etching back surface 21 b. The thickness T4 of the support layer 12 is, for example, 10 μm or more and 50 μm or less.

Even if the invar alloy rolled sheet 21 has a thickness of 10 μm or less, the thickness of the support layer 12 is preferably 10 μm or more in order to improve the strength of the laminate of the support layer 12 and the invar alloy rolled sheet 21 to such an extent that the handling complexity due to the brittleness of the laminate is reduced in the production process of the metal mask base material 10.

In addition, the thickness of the support layer 12 is preferably 50 μm or less in order to prevent an excessive increase in time required for removing the support layer 12 from the metal mask base material 10 by the alkali solution.

The support layer 12 may be laminated on the resist processing surface 21c by being bonded to the resist processing surface 21c after being formed into a sheet shape. Alternatively, the support layer 12 may be laminated on the resist processing surface 21c by applying a coating liquid for forming the support layer 12 to the resist processing surface 21 c.

In the case where the support layer 12 includes the negative resist layer, the support layer 12 is formed by applying a thin film of negative resist to the resist processing surface 21c or applying negative resist to the resist processing surface 21c and then irradiating ultraviolet rays to the entire negative resist.

As shown in fig. 5, in a state where invar rolled sheet 21 and support layer 12 are laminated, surface 21a of invar rolled sheet 21, which is an example of a second processing target etched after the first processing target, is etched by an acidic etching solution by 3 μm or more. The difference between the surface 21a of the invar rolled sheet 21 before etching and the surface 11a of the invar rolled sheet 21 after etching, that is, the invar sheet 11, is an etching thickness T5, and the etching thickness T5 is 3 μm or more.

Thus, the etching of the invar rolled sheet 21 includes: etching the back surface 21b of an invar rolled sheet 21 as an example of a first processing target; thereafter, the surface 21a, which is an example of the second processing object, is etched.

By etching the surface 21a, the thickness T2 of the invar rolled sheet 21 described above with reference to fig. 2 is 10 μm or less, and the surface 21a is roughened so that the surface 21a has a surface roughness Rz of 0.2 μm or more. Thus, an invar sheet 11, which is an example of a metal mask sheet and a metal sheet made of metal and has a surface roughness Rz of each of the front surface 11a and the back surface 11b of 0.2 μm or more, and a metal mask base material 10 in which the invar sheet 11 and the support layer 12 are laminated are obtained.

Since both the front surface 21a and the back surface 21b of invar rolled sheet 21 are etched, a resist layer can be formed on either the resist-treated surface formed by front surface 21a or the resist-treated surface 21c formed by back surface 21 b. This can prevent the surface of the object on which the resist layer is formed from being mistaken, which makes it difficult to obtain the adhesion between the resist layer and the metal mask substrate 10, and further, can prevent a reduction in yield in the production of the metal mask 51 for vapor deposition.

The metal mask substrate 10 is a laminate of an invar sheet 11 and a support layer 12. Therefore, in the transportation of the invar sheet 11 and the post-treatment of the invar sheet 11, the trouble of the processing of the invar sheet 11 due to the fragility of the invar sheet 11 caused by the thickness of the invar sheet 11 being 10 μm or less can be reduced.

The acidic etching solution may be any acidic etching solution used for etching the back surface 21b, and is preferably the same acidic etching solution as used for etching the back surface 21 b. The etching of the front surface 21a may be any of a dip type, a spray type, and a spin type, but is preferably the same as the etching of the rear surface 21 b.

The etching thickness T5 may be at least 3 μm, preferably 10 μm or more, and more preferably 15 μm or more. The etching thickness T5 may be the same as the etching thickness T3 described above, or may be different from each other.

In forming the base material of the invar rolled sheet 21, in general, granular aluminum, magnesium, or the like is mixed as a deoxidizer into the material forming the base material in order to remove oxygen mixed into the material forming the base material. Aluminum and magnesium are oxidized and contained in the material forming the base material in the state of metal oxide such as aluminum oxide and magnesium oxide. When the base material is formed, most of the metal oxide is removed from the base material, but a part of the metal oxide remains in the base material.

As shown in fig. 6, in invar rolled sheet 21, a portion including the center in the thickness direction of invar rolled sheet 21 is a center portion C, a portion including front surface 21a is a first surface layer portion S1, and a portion including back surface 21b is a second surface layer portion S2. The metal oxide is distributed more in the first surface layer portion S1 and the second surface layer portion S2 than in the center portion C.

When the metal mask for vapor deposition is formed by etching the invar sheet 11, the metal oxide becomes a factor that the resist is peeled off from the invar sheet 11 and the invar sheet 11 is excessively etched.

As described above, in the method of manufacturing the metal mask blank 10, since the front surface 21a and the back surface 21b of the invar rolled sheet 21 are etched, at least a part of the first surface layer portion S1 and the second surface layer portion S2 containing a large amount of metal oxide is removed. Thus, as compared with the case where the front surface 21a and the back surface 21b of the invar rolled sheet 21 are not etched, the peeling of the resist due to the metal oxide and the over-etching of the invar sheet 11 can be suppressed, and the etching accuracy of the metal mask base material 10 can be suppressed from being lowered.

As shown in fig. 7, a resist layer 22 is formed on the surface 11a of the invar sheet 11. The resist layer 22 may be formed on the surface 11a by being stuck to the surface 11a after being formed into a sheet shape. Alternatively, the resist layer 22 may be formed on the surface 11a by applying a coating liquid for forming the resist layer 22 to the surface 11 a.

The material for forming the resist layer 22 may be a negative resist or a positive resist. When the material for forming the support layer 12 is a negative resist, the resist layer 22 is preferably formed of the same material as the support layer 12.

As shown in fig. 8, a resist mask 23 is formed by patterning the resist layer 22. The resist mask 23 has a plurality of through holes 23a for etching the invar sheet 11.

When the material for forming the resist layer 22 is a negative resist, the resist layer 22 is exposed by irradiating portions of the resist layer 22 other than the portions corresponding to the through holes 23a of the resist mask 23 with ultraviolet rays. Then, the resist layer 22 is developed with a developer, thereby obtaining a resist mask 23 having a plurality of through holes 23 a.

When the material for forming the resist layer 22 is a positive resist, ultraviolet rays are irradiated to portions of the resist layer 22 corresponding to the through holes 23a of the resist mask 23, and the resist layer 22 is exposed. Then, the resist layer 22 is developed with a developer, thereby obtaining a resist mask 23 having a plurality of through holes 23 a.

As shown in fig. 9, the invar sheet 11 is etched using the resist mask 23. For example, a ferrous chloride solution is used for etching the invar sheet 11. In this way, a plurality of through holes 11c, i.e., mask openings, are formed in the invar sheet 11 so as to penetrate between the front surface 11a and the back surface 11 b. In a cross section of the invar sheet 11 along the thickness direction, the inner peripheral surface of each through hole 11c has a substantially minor arc shape, and the opening area on the front surface 11a is larger than the opening area on the back surface 11b in each through hole 11 c.

Since the invar sheet 11 has a thickness of 10 μm or less, the through-hole 11c that penetrates between the front surface 11a and the back surface 11b can be formed without making the mask opening, in other words, the through-hole 11c, of the invar sheet 11 excessively large, only by etching the invar sheet 11 from the front surface 11 a.

As shown in fig. 10, the invar sheet 31 has a thickness T6 greater than the thickness T1 of the invar sheet 11, i.e., the invar sheet 31 has a thickness T6 greater than 10 μm. In this case, it is necessary to form a through hole penetrating the front surface 31a and the back surface 31b so that the area of the opening on the front surface 31a of the invar sheet 31 is approximately the same as the area of the opening on the front surface 11a of the invar sheet 11, and then etch the invar sheet 31 from the front surface 31a and the back surface 31 b.

Thus, a through-hole 31e is formed, which is composed of a first hole 31c opening on the front surface 31a and a second hole 31d opening on the rear surface 31 b. The opening area at the connection portion of the first hole 31c and the second hole 31d is smaller than the opening area of the second hole 31d on the back surface 31b in the direction orthogonal to the thickness of the invar alloy sheet 31.

When the invar sheet 31 having such through holes 31e is used as a metal mask for vapor deposition, the invar sheet 31 is disposed between a vapor deposition source and a film formation target in a state where the back surface 31b of the invar sheet 31 faces the film formation target. The connecting portion constitutes a portion of the invar sheet 31 which becomes a shadow of the vapor deposition metal mask when the film formation object is viewed from the vapor deposition particles, and therefore it is difficult to obtain a shape which follows the shape of the mask opening of the second hole 31d in the film formation object. Therefore, the depth of the second hole 31d, in other words, the distance between the back surface 31b and the connecting portion is preferably small.

On the other hand, since the invar sheet 11 has no connecting portion in the through hole 11c, a portion which becomes a shadow of the vapor deposition metal mask when the deposition target is observed from the vapor deposition particles can be reduced as compared with the invar sheet 31. As a result, a shape that more closely follows the shape of the mask opening can be obtained in the object to be film-formed.

As shown in fig. 11, the resist mask 23 located on the metal mask base material 10 described above with reference to fig. 9 is removed. When the resist mask 23 is removed from the laminate of the metal mask substrate 10 and the resist mask 23, a protective layer for protecting the support layer 12 may be formed on a surface of the support layer 12 opposite to the surface in contact with the invar sheet 11. According to the protective layer, the solution for removing the resist mask 23 can be suppressed from dissolving the support layer 12.

As shown in fig. 12, after the resist mask 23 is removed, the metal mask base material 10 is exposed to an alkaline solution, whereby the support layer 12 is chemically removed from the metal mask base material 10. Thereby, the metal mask sheet 41 for vapor deposition is obtained. The metal mask sheet 41 for vapor deposition has a front surface 41a corresponding to the front surface 11a of the invar alloy sheet 11, a back surface 41b corresponding to the back surface 11b of the invar alloy sheet 11, and through holes 41c corresponding to the through holes 11c of the invar alloy sheet 11.

At this time, since the support layer 12 is chemically removed from the metal mask base material 10, it is possible to suppress the occurrence of wrinkles and deformation in the invar sheet 11 without applying an external force to the invar sheet 11, as compared with the case where the support layer 12 is physically peeled from the invar sheet 11.

The alkaline solution may be any solution that can dissolve the support layer 12 and thereby peel the support layer 12 from the invar sheet 11, and is, for example, an aqueous sodium hydroxide solution. When the metal mask base material 10 is exposed to the alkaline solution, the metal mask base material 10 may be immersed in the alkaline solution, the alkaline solution may be blown to the support layer 12 of the metal mask base material 10, or the alkaline solution may be dropped onto the support layer 12 of the metal mask base material 10 rotated by a rotator.

As shown in fig. 13, a vapor deposition metal mask 51 having a predetermined length is cut out from the vapor deposition metal mask sheet 41. The vapor deposition metal mask 51 has a surface 51a corresponding to the surface 41a of the vapor deposition metal mask sheet 41, a back surface 51b corresponding to the back surface 41b of the vapor deposition metal mask sheet 41, and through holes 51c corresponding to the through holes 41c of the vapor deposition metal mask sheet 41.

Then, when vapor deposition of the organic layer is performed, a metal mask 51 for vapor deposition is attached to the frame. That is, the metal mask 51 for vapor deposition is used for vapor deposition of an organic layer in a state of being attached to the metal frame 52 through the adhesive layer 53. In the vapor deposition metal mask 51, a part of the back surface 51b of the vapor deposition metal mask 51 faces a part of the frame 52, and the adhesive layer 53 is positioned between the vapor deposition metal mask 51 and the frame 52. The vapor deposition metal mask 51 may be attached to the frame 52 with the adhesive layer 53 in a state where a part of the surface 51a of the vapor deposition metal mask 51 faces a part of the frame 52 and the adhesive layer 53 is positioned between the surface 51a of the vapor deposition metal mask 51 and the frame 52.

As shown in fig. 14, the vapor deposition metal mask 51 has a rectangular shape and the frame 52 has a rectangular frame shape in a plan view facing the surface 51a of the vapor deposition metal mask 51. Each through hole 51c has a rectangular shape in a plan view facing the surface 51 a. That is, the opening on the surface 51a of the through hole 51c has a rectangular shape. The opening of the through hole 51c in the rear surface 51b also has a rectangular shape. The plurality of through holes 51c are arranged at equal intervals in one direction and are arranged at equal intervals in another direction orthogonal to the one direction. The vapor deposition metal mask 51 is disposed between the vapor deposition source and the film formation target in a state where the rear surface 51b of the vapor deposition metal mask 51 faces the film formation target.

In fig. 14, the left-right direction on the paper surface is the arrangement direction of pixels in the film formation target. In fig. 14, the distance between the through holes 51c adjacent to each other in the left-right direction is smaller than the width of the through holes 51c in the left-right direction, but the distance between the through holes 51c adjacent to each other in the left-right direction is preferably 2 times or more the width of the through holes 51c in the left-right direction.

[ test examples ]

The test example will be described with reference to fig. 15 to 20.

[ test example 1]

An invar alloy rolled sheet having a thickness of 30 μm was prepared as an invar alloy rolled sheet of test example 1.

[ test example 2]

An invar alloy rolled sheet having a thickness of 30 μm was prepared, and the surface of the invar alloy rolled sheet was etched by 3 μm by spraying an acidic etching solution onto the surface of the invar alloy rolled sheet, to obtain an invar alloy sheet of test example 2 having a treated surface for a resist. In addition, as the acidic etching solution, a solution obtained by mixing perchloric acid with a mixed solution of a second iron perchlorate solution and a ferrous chloride solution is used.

[ test example 3]

An invar alloy rolled sheet having a thickness of 30 μm was prepared, and the surface of the invar alloy rolled sheet was etched by 4.5 μm under the same conditions as in test example 2, to obtain an invar alloy sheet of test example 3 having a treated surface for a resist.

[ test example 4]

An invar alloy rolled sheet having a thickness of 30 μm was prepared, and the surface of the invar alloy rolled sheet was etched by 10 μm under the same conditions as in test example 2, to obtain an invar alloy sheet of test example 4 having a treated surface for a resist.

[ surface photography with scanning Electron microscope ]

The surface of test example 1 and the resist-treated surface of each of test examples 2 to 4 were photographed by a scanning electron microscope, and SEM images were generated. The magnification of a scanning electron microscope (JSM-7001F, manufactured by Nippon electronics Co., Ltd.) was 10000 times, the acceleration voltage was 10.0kV, and the working distance was 9.7 mm.

As shown in fig. 15, it was confirmed that the flatness of the surface of the invar rolled sheet of test example 1 was the highest, and that rolling marks, which are ribs extending in the vertical direction on the paper surface, were observed on the surface of the invar rolled sheet of test example 1. As shown in fig. 16 and 17, it was confirmed that a level difference was formed on the resist processed surface of the invar sheet of test example 2 and the resist processed surface of the invar sheet of test example 3. As shown in fig. 18, it was confirmed that a larger level difference was formed on the treated surface of the invar sheet of test example 4 as compared with the treated surfaces of the invar sheet of test example 2 and the invar sheet of test example 3. Further, it was confirmed that the roll marks were almost eliminated by etching in the resist-treated surfaces of the invar alloy sheets shown in fig. 16 to 18.

[ measurement of surface roughness by atomic force microscope ]

A test piece including the surface of the invar rolled sheet of test example 1 as the surface was prepared, and a test piece including the resist-treated surface of the invar sheet of each of test examples 2 to 4 as the surface was prepared. Then, the surface roughness of the scanning region, which is a region having a square shape with a side length of 5 μm, was measured on the surface of each test piece.

The surface roughness of the surface of each test example was measured by a method conforming to JIS B0601-2001 using an atomic force microscope (AFM5400L, Hitachi High-TechScience, Ltd.). The measurement results of the surface roughness are shown in table 1 below. Further, based on the measurement results, the surface area ratio of each test piece was calculated as the ratio of the surface area of the scanning region to the area of the scanning region. In other words, the surface area ratio is a value obtained by dividing the surface area of the scanning region by the area of the scanning region.

Among the parameters of the surface roughness described in table 1, Rz is the maximum height that is the sum of the height of the highest peak and the depth of the deepest valley in the profile having the reference length, and Ra is the arithmetic average roughness of the profile having the reference length. Rp is the height of the highest peak in the profile curve having the reference length, and Rv is the depth of the deepest valley in the profile curve having the reference length. In the following, Rz, Ra, Rp, and Rv are each expressed in μm.

[ Table 1]

As shown in table 1, it was confirmed that the invar rolled sheet of test example 1 had a surface roughness Rz of 0.17, a surface roughness Ra of 0.02, a surface roughness Rp of 0.08 and a surface roughness Rv of 0.09. In addition, it was confirmed that the invar rolled sheet of test example 1 had a surface area ratio of 1.02.

It was confirmed that the surface roughness Rz of the treated surface for resist of the invar alloy sheet of test example 2 was 0.24, the surface roughness Ra was 0.02, the surface roughness Rp was 0.12, and the surface roughness Rv was 0.12. In addition, it was confirmed that the surface area ratio of the invar sheet of test example 2 was 1.23 on the treated surface for resist.

It was confirmed that the surface roughness Rz of the treated surface for resist of the invar alloy sheet of test example 3 was 0.28, the surface roughness Ra was 0.03, the surface roughness Rp was 0.15, and the surface roughness Rv was 0.13. In addition, it was confirmed that the surface area ratio of the invar sheet of test example 3 was 1.13 on the treated surface for resist.

It was confirmed that the surface roughness Rz of the treated surface for resist of the invar alloy sheet of test example 4 was 0.30, the surface roughness Ra was 0.03, the surface roughness Rp was 0.17, and the surface roughness Rv was 0.13. In addition, it was confirmed that the surface area ratio of the invar sheet of test example 4 was 1.22 on the treated surface for resist.

Thus, it was confirmed that the surface roughness Rz of the treated surface for resist was 0.2 μm or more in the invar sheet obtained by etching the surface of the invar rolled sheet by 3 μm or more. Further, it can be confirmed that the greater the thickness of etching, the greater the surface roughness Rz of the treated surface for resist, and therefore the thickness of etching of the surface of the invar rolled sheet is preferably 4.5 μm, more preferably 10 μm.

Further, an invar alloy rolled sheet having a thickness of 30 μm was prepared, and the front and back surfaces of the invar alloy rolled sheet were each etched by 10 μm under the above conditions, thereby obtaining an invar alloy sheet having a thickness of 10 μm. At this time, a sheet made of polyimide having a thickness of 20 μm was bonded as a support layer to the treated surface for resist obtained from the back surface of the invar rolled sheet.

From such an invar sheet, the inventors of the present application have confirmed that a through hole penetrating between the front surface and the back surface of the invar sheet can be formed only by etching the invar sheet from the front surface thereof. The inventors of the present application have also confirmed that, in such a through hole, the opening area on the front surface of the invar sheet and the opening area on the back surface of the invar sheet have desired sizes, respectively.

Further, after a dry film resist was attached to the surface of the invar rolled sheet of test example 1 and the dry film resist was patterned, the invar rolled sheet of test example 1 was etched to form a plurality of concave portions on the surface.

Then, after a dry film resist was attached to the resist processing surface of each of the invar sheets of test examples 2 to 4 and the dry film resist was patterned, each of the invar sheets of test examples 2 to 4 was etched to form a plurality of recesses in the resist processing surface. In addition, in test examples 2 to 4, as a method of forming a pattern of a dry film resist, the same method as in test example 1 was used, and further, etching conditions of the invar sheet were set to the same conditions as in test example 1.

It was confirmed that in each of test examples 2 to 4, the variation in the size of the openings on the resist-treated surface was smaller than that in test example 1. That is, as in each of test examples 2 to 4, if the surface roughness Rz is 0.2 μm or more, it was confirmed that the adhesion between the resist layer and the invar sheet can be improved, and thus the reduction in the shape accuracy of the mask opening can be suppressed.

[ test example 5]

An invar alloy rolled sheet having a thickness of 30 μm was prepared as an invar alloy rolled sheet of test example 5.

[ test example 6]

An invar alloy rolled sheet having a thickness of 30 μm was prepared, and the surface of the invar alloy rolled sheet was etched by 3 μm under the same conditions as in test example 2, to obtain an invar alloy sheet of test example 6 having a treated surface for a resist.

[ test example 7]

An invar alloy rolled sheet having a thickness of 30 μm was prepared, and the surface of the invar alloy rolled sheet was etched by 10 μm under the same conditions as in test example 2, to obtain an invar alloy sheet of test example 7 having a treated surface for a resist.

[ test example 8]

An invar alloy rolled sheet having a thickness of 30 μm was prepared, and the surface of the invar alloy rolled sheet was etched by 15 μm under the same conditions as in test example 2, to obtain an invar alloy sheet of test example 8 having a treated surface for a resist.

[ test example 9]

An invar alloy rolled sheet having a thickness of 30 μm was prepared, and the surface of the invar alloy rolled sheet was etched by 16 μm under the same conditions as in test example 2, to obtain an invar alloy sheet of test example 9 having a treated surface for a resist.

[ counting of particle traces ]

3 test pieces each including a part of the surface of the invar rolled sheet of test example 5 as the surface were prepared, and the 3 test pieces were square-shaped test pieces each having a side length of 2 mm. Further, 3 test pieces each including a part of the resist-treated surface of each of the invar alloy pieces of test examples 6 to 9 as a surface were prepared, and each of the test pieces had a square shape having a side length of 2 mm.

The surface of each test piece was observed with a scanning electron microscope (the same as above), and the number of particle marks of each test piece was counted. The grain mark is a mark of a metal oxide grain separated from an invar rolled sheet or an invar sheet, and at least one of the first grain mark and the second grain mark can be confirmed in each test piece. The results of counting the particle marks are shown in table 2 below.

As shown in fig. 19, the first particle trace is a hemispherical recess that defines a substantially circular region in a plan view facing the surface of the test piece. It was confirmed that the first particle scars had a diameter of 3 μm to 5 μm.

On the other hand, as shown in fig. 20, the second particle trace is a recess having an elliptical hammer shape and defining a substantially elliptical region in a plan view facing the surface of the test piece. It was confirmed that the major axis of the second particle trace was 3 μm to 5 μm.

When the first particle trace and the second particle trace were photographed, the magnification was set to 5000 times, the acceleration voltage was set to 10.0kV, and the working distance was set to 9.7mm in the scanning electron microscope.

[ Table 2]

As shown in table 2, in test example 5, it was confirmed that test specimen 1 had 1 first particle mark, and that both test specimens 2 and 3 had no particle mark. That is, in test example 5, it was confirmed that the total number of first particle scratches was 1 and the total number of second particle scratches was 0.

In test example 6, it was confirmed that test specimen 1 had 4 first particle scratches and 1 second particle scratch, test specimen 2 had 9 first particle scratches, and test specimen 3 had 8 first particle scratches and 2 second particle scratches. That is, in test example 6, the total number of the first particle scratches was 21, and the total number of the second particle scratches was 3.

In test example 7, it was confirmed that test specimen 1 had 5 first particle scratches and 1 second particle scratch, test specimen 2 had 6 first particle scratches and 1 second particle scratch, and test specimen 3 had 5 first particle scratches and 2 second particle scratches. That is, in test example 7, it was confirmed that the total number of the first particle scratches was 16, and the total number of the second particle scratches was 4.

In test example 8, it was confirmed that test specimen 1 had 5 first particle scratches, test specimen 2 had 2 first particle scratches, and test specimen 3 had 6 first particle scratches and 1 second particle scratch. That is, in test example 8, it was confirmed that the total number of the first particle scratches was 13 and the total number of the second particle scratches was 1.

In test example 9, it was confirmed that test specimen 1 had 4 first particle scratches, test specimen 2 had 5 first particle scratches, test specimen 3 had 5 first particle scratches, and all of test specimens 1 to 3 had no second particle scratches. That is, in test example 9, it was confirmed that the total number of first particle scratches was 14.

In test examples 6 and 7 having a plurality of second particle marks, it was confirmed that the major axis directions of the second particle marks were aligned and were parallel to the rolling direction of the invar rolled sheet for forming the invar sheet.

Thus, it was confirmed that if the surface of the invar rolled sheet was etched by 16 μm or more, the second particle trace could be removed from the resist-treated surface of the invar sheet. Further, it was confirmed that omission of the first particle scars can be reduced by etching the surface of the invar rolled sheet by 10 μm or more, and the number of the first particle scars can be further reduced by etching the surface of the invar rolled sheet by 15 μm or more.

From these results, it can be said that by etching the surface of the invar rolled sheet by 10 μm or more, more preferably by etching by 15 μm or more, the particles of the metal oxide in the invar rolled sheet can be reduced. Therefore, it can be said that it is effective to etch the surface of the invar rolled sheet by 10 μm or more, preferably by 15 μm or more, in order to suppress the influence of the detachment of the metal oxide on the shape accuracy of the through hole formed by etching the metal mask base material.

As described above, according to 1 embodiment of the method for producing a metal mask substrate, the method for producing a vapor deposition metal mask, the metal mask substrate, and the vapor deposition metal mask, the following effects can be obtained.

(1) Since the invar sheet 11 has a thickness of 10 μm or less, the depth of the mask opening formed in the invar sheet 11 can be 10 μm or less. This can reduce a portion which becomes a shadow of the vapor deposition metal mask 51 when the film formation object is viewed from the vapor deposition particles, that is, suppress the shadow effect, and therefore, the film formation object can be given a shape which follows the shape of the mask opening, and further, high definition of film formation using the vapor deposition metal mask 51 can be achieved.

In addition, when the mask opening is formed in the invar sheet 11, the adhesion between the resist layer 22 and the invar sheet 11 can be improved compared to before roughening. In addition, since the reduction in shape accuracy due to the peeling of the resist layer 22 from the invar sheet 11 and the like can be suppressed in the formation of the mask opening, high definition of film formation using the vapor deposition metal mask 51 can be achieved in this regard as well.

(2) The resist layer 22 can be formed on either the resist-treated surface formed on the front surface 21a of the invar alloy rolled sheet 21 or the resist-treated surface 21c formed on the back surface 21b of the invar alloy rolled sheet 21. Therefore, it is possible to suppress difficulty in obtaining adhesion between the resist layer 22 and the metal mask substrate 10 due to mismatching of the surface on which the resist layer 22 is to be formed, and further, it is possible to suppress a decrease in yield in manufacturing the metal mask 51 for vapor deposition.

(3) In the transportation of the invar sheet 11 and the post-treatment of the invar sheet 11, the trouble of the handling of the invar sheet 11 due to the fragility of the invar sheet 11 caused by the thickness of the invar sheet 11 being 10 μm or less can be reduced.

(4) Since no external force acts on the invar sheet 11, wrinkles and deformation of the invar sheet 11 can be suppressed, as compared with the case where the support layer 12 is physically peeled off from the invar sheet 11.

The above-described embodiment can also be implemented by appropriately changing the embodiment as follows.

The support layer 12 may also be physically peeled from the invar sheet 11. That is, an external force may be applied to at least one of the support layer 12 and the invar sheet 11 so that peeling occurs at the interface between the support layer 12 and the invar sheet 11. In such a configuration, the same effect as (1) above can be obtained by roughening the surface of the resist-treated surface so that Rz is 0.2 μm or more and etching the invar rolled sheet 21 so that the thickness of the etched invar rolled sheet 21 is 10 μm or less.

However, as described above, in order to suppress wrinkles and deformation of the invar sheet 11, it is preferable to chemically remove the support layer 12 from the metal mask substrate 10 by an alkaline solution.

In the etching of the front surface 21a and the back surface 21b of the invar rolled sheet 21, the back surface 21b may be etched before the front surface 21a, or the front surface 21a and the back surface 21b may be etched simultaneously. The same effect as that of (1) above can be obtained by roughening the surface of the resist-treated surface so that the surface roughness Rz is 0.2 μm or more and etching the invar rolled sheet 21 so that the thickness of the etched invar rolled sheet 21 is 10 μm or less, regardless of the order in which the front surface 21a and the back surface 21b are etched.

The target of processing in the invar rolled sheet 21 may be only the front surface 21a or only the back surface 21b of the invar rolled sheet 21. In such a configuration, the same effect as (1) above can be obtained by roughening the surface of the resist-treated surface so that Rz is 0.2 μm or more and etching the invar rolled sheet 21 so that the thickness of the etched invar rolled sheet 21 is 10 μm or less.

In the invar rolled sheet 21, when only the front surface 21a is to be processed, it is preferable that the support layer 12 is laminated on the back surface 21b before etching the front surface 21a, and the front surface 21a is etched in a state where the invar rolled sheet 21 and the support layer 12 are laminated. When only the back surface 21b is to be processed, it is preferable to form the support layer 12 on the front surface 21a before etching the back surface 21b and etch the back surface 21b in a state where the invar rolled sheet 21 and the support layer 12 are laminated. With such a configuration, the same effect as (3) above can be obtained.

Etching of the processed object in the invar rolled sheet 21 can be performed in a state where the support layer 12 is not formed on the invar rolled sheet 21 regardless of whether the processed object is one of the front surface 21a and the back surface 21b or both of the front surface 21a and the back surface 21 b. In such a configuration, the same effect as (1) above can be obtained by roughening the surface of the resist-treated surface so that Rz is 0.2 μm or more and etching the invar rolled sheet 21 so that the thickness of the etched invar rolled sheet 21 is 10 μm or less.

In this case, the metal mask base material may have a structure without the support layer 12, that is, a structure including only the invar sheet 11. Alternatively, the metal mask base material, which is a laminate of the invar sheet 11 and the support layer 12, may be obtained by obtaining the invar sheet 11 from the invar rolled sheet 21 and then laminating the support layer 12 on one surface of the invar sheet 11.

As shown in fig. 21, if the material for forming the support layer 12 is polyimide, only the portion of the support layer 12 that overlaps the through-hole 11c of the invar sheet 11 in the thickness direction of the metal mask base 10 may be removed from the invar sheet 11 when the support layer 12 is removed from the metal mask base 10. In other words, when the support layer 12 is removed from the metal mask base material 10, only the edge portion of the support layer 12 except the portion outside all the through holes 11c may be removed as the edge portion of the support layer 12 in a plan view facing the back surface 11b of the invar alloy sheet 11.

In such a configuration, the vapor deposition metal mask 61 is composed of the invar sheet 11 and the polyimide frame 12a having a rectangular frame shape. The invar sheet 11 has a plurality of through holes 11c, and the polyimide frame 12a has a rectangular frame shape in a plan view facing the back surface 11b of the invar sheet 11, and surrounds all the through holes 11 c.

The polyimide frame 12a included in the vapor deposition metal mask 61 can function as an adhesive layer when the vapor deposition metal mask 61 is attached to the frame 52. Therefore, the metal mask 61 for vapor deposition is attached to the frame 52 in a state where the polyimide frame 12a of the metal mask 61 for vapor deposition is in contact with the frame 52.

As shown in fig. 22, if the material for forming the support layer 12 is polyimide, the support layer 12 may not be removed from the metal mask substrate 10. In such a configuration, when the vapor deposition metal mask 62 is attached to the frame 52, the invar sheet 11 having the plurality of through holes 11c and the support layer 12 overlapping the entire back surface 11b of the invar sheet 11 are configured.

The support layer 12 included in the vapor deposition metal mask 62 can function as an adhesive layer when the vapor deposition metal mask 62 is attached to the frame 52, similarly to the polyimide frame 12a described above. Therefore, the vapor deposition metal mask 62 is attached to the frame 52 in a state where the support layer 12 of the vapor deposition metal mask 62 is in contact with the frame 52.

In such a vapor deposition metal mask 62, after the vapor deposition metal mask 62 is attached to the frame 52, only a portion of the support layer 12 that overlaps the through-hole 11c of the invar sheet 11 in the thickness direction of the metal mask base 10 may be removed from the invar sheet 11. In other words, only the edge portion of the support layer 12, which is the edge portion of the support layer 12, except for the portion outside all the through holes 11c, may be removed in a plan view facing the back surface 11b of the invar alloy sheet 11.

Fig. 23 shows a planar structure of the invar sheet, and is a planar structure in a plan view facing a processing surface for a resist obtained by etching of a processing target in the invar rolling sheet 21. In fig. 23, the first particle marks and the second particle marks are dotted to clarify the difference between the first particle marks and the second particle marks and the portions of the resist processing surface other than the first particle marks and the second particle marks.

As shown in fig. 23, if the thickness of the etching target of invar rolled sheet 21 is 3 μm to 10 μm, the resist processing surface 71a of invar sheet 71 has a plurality of first particle marks 72 and a plurality of second particle marks 73. Each first particle mark 72 is a recess having a hemispherical shape, and a first diameter D1, which is a diameter of the first particle mark 72, is 3 μm or more and 5 μm or less.

Each second particle trace 73 has an elliptical-hammer-shaped recess, and a second diameter D2, which is the major diameter of each second particle trace 73, is not less than 3 μm and not more than 5 μm, and the major diameter directions of the second particle traces 73 are aligned. The major axis direction of each second grain mark 73 is parallel to the rolling direction of the invar alloy sheet 71.

Since the invar alloy piece 71 is generally manufactured by rolling, particles made of an oxide such as a deoxidizer added in the manufacturing process of the invar alloy piece 71 are not always mixed into the invar alloy piece 71. A part of the particles mixed into the surface of the invar alloy sheet 71 extends in the rolling direction of the invar alloy sheet 71 and has an elliptical hammer shape having a major diameter in the rolling direction. If such particles remain in the resist processing surface 71a at the mask opening formation portion, there is a possibility that etching for forming the mask opening is hindered by the particles.

In this regard, according to the above configuration, the following effects can be obtained.

(5) Since the particles have been removed from the resist processing surface 71a, the resist processing surface 71a has a plurality of second particle marks 73 in the form of elliptical hammers aligned in the major-diameter direction. Therefore, in the formation of the mask opening, the accuracy of the shape and size of the mask opening can be improved as compared with the case where particles remain in the invar sheet 71.

The material for forming the metal rolled sheet, and further the metal mask sheet and the metal sheet may be a material other than invar alloy as long as it is a pure metal or an alloy.

Each step of the method for manufacturing the vapor deposition metal mask 51 may be performed on an invar rolled sheet cut in advance to a size corresponding to one vapor deposition metal mask 51. In such a case, the resist mask and the support layer are removed from the invar sheet corresponding to the invar rolled sheet to obtain a vapor deposition mask.

Alternatively, each step of the method for producing the metal mask base material 10 may be performed for an invar rolled sheet 21 having a size corresponding to a plurality of vapor deposition metal masks 51, and the obtained metal mask base material 10 may be cut into metal mask base material sheets having a size corresponding to one vapor deposition metal mask 51. Then, the metal mask substrate sheet may be subjected to a step of forming a resist layer, a step of forming a resist mask, a step of etching the invar sheet, and a step of removing the support layer.

The vapor deposition metal mask 51 may have a shape other than a rectangular shape, for example, a square shape, or a polygonal shape other than a quadrangular shape, in a plan view facing the front surface 51 a.

The openings in the front surface 51a and the openings in the rear surface 51b of each through hole 51c of the vapor deposition metal mask 51 may have shapes other than rectangular shapes, such as square shapes and circular shapes.

When the one direction is a first direction and a direction orthogonal to the first direction is a second direction in a plan view facing the surface 51a, the plurality of through holes 51c may be arranged as follows. That is, the plurality of through holes 51c along the first direction form one row, and the plurality of through holes 51c are formed at a predetermined pitch in the first direction. In the plurality of through holes 51c constituting each row, the positions in the first direction overlap each other every 1 row. On the other hand, in the rows adjacent to each other in the second direction, the positions of the through holes 51c in the other row are shifted by 1/2 pitches in the first direction with respect to the positions of the through holes 51c in the first direction in the one row. In other words, the plurality of through holes 51c may be arranged in a staggered pattern (in a shape of a thousand-bird lattice).

In short, in the vapor deposition metal mask 51, the plurality of through holes 51c may be arranged so as to correspond to the arrangement of the organic layer formed using the vapor deposition metal mask 51. In the embodiment, the plurality of through holes 51c are arranged so as to correspond to the lattice arrangement of the organic EL device, and the plurality of through holes 51c of the above-described modification are arranged so as to correspond to the Δ (Delta) arrangement of the organic EL device.

In the above embodiment, when the one direction is the first direction and the direction orthogonal to the first direction is the second direction in a plan view facing the surface 51a, each through hole 51c is separated from another through hole 51c adjacent to the first direction and another through hole 51c adjacent to the second direction. However, the opening on the surface 51a of each through hole 51c may be connected to the opening on the surface 51a of another through hole 51c adjacent to each other in the first direction, or may be connected to the opening on the surface 51a of the through hole 51c adjacent to each other in the second direction. Alternatively, the opening on the surface 51a of each through hole 51c may be continuous with the opening on the surface 51a of another through hole 51c adjacent to each other in both the first direction and the second direction. In such a vapor deposition metal mask, the thickness of the portion where the 2 through holes 51c are connected may be thinner than the thickness of the portion where the through holes 51c are not provided, that is, the portion where the through holes 51c are not etched in the step of forming the through holes 51c, which is the outer edge of the vapor deposition metal mask.

The metal mask for vapor deposition is not limited to the metal mask for vapor deposition used for forming the organic layer of the organic EL device, and may be used for forming wirings provided in various devices such as a display device other than the organic EL device, or for forming functional layers provided in the various devices.

Description of the symbols

10 … metal mask substrate, 11, 31, 71 … invar sheet, 11a, 21a, 31a, 41a, 51a … surface, 11b, 21b, 31b, 41b, 51b … back surface, 11C, 23a, 31e, 41C, 51C … through hole, 12 … support layer, 12a … polyimide frame, 21 … invar rolled sheet, 21C, 71a … resist processed surface, 22 … resist layer, 23 … resist mask, 31C … first hole, 31d … second hole, 41 … vapor deposition metal mask, 51, 61, 62 … vapor deposition metal mask, 52 … frame, 53 …, 72 … first particle trace, 73 … second particle trace, C … central portion, S1 … first surface layer portion, S2 … second surface layer portion.