1. A method for controlling oxygen content in a loading and unloading chamber of semiconductor thermal treatment equipment is characterized by comprising the following steps:

acquiring the current target oxygen content and the detected oxygen content of the loading and unloading chamber;

determining a first deviation value according to the detected oxygen content and the target set oxygen content;

determining an initial purge flow according to the first deviation value;

acquiring a pressure flow conversion coefficient and a current pressure value of the loading and unloading chamber, and converting the pressure value into a reference purge flow according to the pressure flow conversion coefficient;

determining a second deviation value according to the initial purge flow and the reference purge flow;

and determining a final purging flow according to the second deviation value, and purging the loading and unloading cavity by adopting the final purging flow so as to control the oxygen content.

2. The method of claim 1, wherein the determining an initial purge flow based on the first deviation value comprises:

calculating by adopting a preset first PID algorithm based on the current first deviation value and the historical first deviation value, and determining the initial purge flow;

determining a final purge flow based on the second deviation value comprises:

and calculating by adopting a preset second PID algorithm based on the current second deviation value and the historical second deviation value, and determining the final purge flow.

3. The method of claim 2,

the formula of the first PID algorithm is as follows:

u_n＝u_n-1+Δu

Δu＝K_p*(e_n-e_n-1)+K_i*e_n+K_d*(e_n-2e_n-1+e_n-2)

wherein u is_nFor the current initial purge flow, u_n-1Δ u is the increment of the initial purge flow, e_nIs the current first deviation value, e_n-1The first deviation value of the last time, e_n-2Is the first deviation value, K, before the last time_pIs a proportionality coefficient, K_iIs the integral coefficient, K_dIs an integral coefficient;

and/or the formula of the second PID algorithm is as follows:

u′_n＝u′_n-1+Δu′

Δu′＝K_p*(e′_n-e′_n-1)+K_i*e′_n+K_d*(e′_n-2e′_n-1+e′_n-2)

wherein u'_nIs the current final purge flow, u'_n-1Delta u ' for the last final purge flow, delta u ' is the increment of the final purge flow, e '_nIs the current second deviation value, e'_n-1Is the second deviation value of, e 'of the previous time'_n-2The second deviation value, K, before the last time_pIs a proportionality coefficient, K_iIs the integral coefficient, K_dIs an integral coefficient.

4. The method of any of claims 1-3, further comprising, prior to said purging the chamber with the final purge flow:

when the difference value between the current final purge flow and the last final purge flow is smaller than or equal to a preset threshold value, replacing the current final purge flow with the last final purge flow.

5. The method of any of claims 1-3, further comprising, prior to said purging the chamber with the final purge flow:

filtering the final purge flow value by adopting the following formula:

y_n＝a₁*y_dn+a₂*y_n-1+a₁*y_n-2

wherein, y_nThe final purge flow value, y, for this output_dnFor the final purge flow value, y, without filtering_n-1The final purge flow value, y, output for the last time_n-2The final purge flow value, a, output for the previous time₁As filter parameters, a₂Are filter parameters.

6. The method of any one of claims 1-3, wherein said obtaining a target oxygen content for the loadlock chamber comprises:

obtaining the target oxygen content according to the following formula:

s'_mainWhen < sv-d, s_main＝s′_main+t*rate；

S'_mainWhen > sv-d, s_main＝s′_main-t*rate；

In sv-d < s'_mainWhen < sv + d, s_main＝sv；

Wherein s is_mainIs the target oxygen content, s'_mainFor the currently set oxygen content, sv is the input oxygen content, d is the deviation between the currently set oxygen content and the input oxygen content, t is the calculation period, rate is the step rate。

7. The method of any one of claims 1-3, wherein said converting the pressure value to a reference purge flow according to the pressure-flow conversion factor comprises:

limiting the pressure value in an interval to obtain the pressure value after the interval is limited;

and converting the pressure value after interval limitation into the reference purge flow according to the pressure flow conversion coefficient.

8. The method of claim 7, wherein said interval defining said pressure values comprises:

updating the pressure value to a first pressure threshold if the pressure value is greater than the first pressure threshold;

updating the pressure value to a second pressure threshold if the pressure value is less than the second pressure threshold;

wherein the second pressure threshold is less than the first pressure threshold.

9. A method according to any one of claims 1 to 3, wherein the load and unload chamber is purged with an inert gas.

10. A semiconductor thermal processing apparatus, comprising: a controller and a loading and unloading chamber, wherein the loading and unloading chamber is provided with a detection device and a purging device, wherein,

the detection device is used for detecting the oxygen content and the pressure value in the loading and unloading chamber;

the controller is used for acquiring the current target oxygen content and the detected oxygen content of the loading and unloading chamber; determining a first deviation value according to the detected oxygen content and the target oxygen content; determining an initial purge flow according to the first deviation value; acquiring a pressure-flow conversion coefficient and a current pressure value of the cavity, and converting the pressure value into a reference purge flow according to the pressure-flow conversion coefficient; determining a second deviation value according to the initial purge flow and the reference purge flow; and determining a final purging flow according to the second deviation value, and purging the loading and unloading cavity by adopting the final purging flow to control the purging device so as to control the oxygen content.

Background

In a semiconductor thermal processing apparatus having a chamber (LA) for loading and/or unloading a silicon wafer, micro-oxygen, micro-positive pressure control of the chamber is a key performance index.

During the transportation of the silicon wafer, an unnecessary oxide layer is generated under the influence of oxygen molecules in the chamber, and the oxygen content in the chamber can be controlled by purging with an inert gas (such as high purity nitrogen) under the closed-loop control of an oxygen analyzer and a Mass Flow Controller (MFC). Meanwhile, in order to prevent the pressure change of the chamber from exceeding a safety range in the micro-oxygen control process, the pressure in the loading and unloading chamber needs to be controlled, and the reliable operation of the micro-positive pressure system under the condition of good micro-oxygen control is ensured.

In the oxygen control process, the chamber is purged by inert gas with a certain flow, oxygen is discharged out of the chamber, the oxygen content of the chamber meets the process requirements, and meanwhile, the micro-positive pressure of the chamber is kept, so that external air can be effectively prevented from entering the chamber by the micro-positive pressure, and the oxygen content control effect is ensured.

However, the existing scheme is a hysteresis window control mode, which generally has two modes of large flow oxygen control and small flow oxygen control, i.e. one of the flow oxygen control is selected only when a certain critical point is reached, which is relatively solidified and difficult to adapt to the change in the chamber in time.

Disclosure of Invention

In view of the above problems, it is proposed to provide a method for controlling oxygen content in a semiconductor thermal processing apparatus and an unloading chamber thereof, which overcomes or at least partially solves the above problems, comprising:

a method for controlling the oxygen content in a loading and unloading chamber of semiconductor heat treatment equipment comprises the following steps:

acquiring the current target oxygen content and the detected oxygen content of the loading and unloading chamber;

determining a first deviation value according to the detected oxygen content and the target oxygen content;

determining an initial purge flow according to the first deviation value;

acquiring a pressure flow conversion coefficient and a current pressure value of the loading and unloading chamber, and converting the pressure value into a reference purge flow according to the pressure flow conversion coefficient;

determining a second deviation value according to the initial purge flow and the reference purge flow;

and determining a final purging flow according to the second deviation value, and purging the loading and unloading cavity by adopting the final purging flow so as to control the oxygen content.

Optionally, the determining an initial purge flow from the first deviation value comprises:

calculating by adopting a preset first PID algorithm based on the current first deviation value and the historical first deviation value, and determining the initial purge flow;

determining a final purge flow based on the second deviation value comprises:

and calculating by adopting a preset second PID algorithm based on the current second deviation value and the historical second deviation value, and determining the final purge flow.

Optionally, the formula of the first PID algorithm is:

u_n＝u_n-1+Δu

Δu＝K_p*(e_n-e_n-1)+K_i*e_n+K_d*(e_n-2e_n-1+e_n-2)

wherein u is_nFor the current initial purge flow, u_n-1Δ u is the increment of the initial purge flow, e_nIs the current first deviation value, e_n-1The first deviation value of the last time, e_n-2Is the first deviation value, K, before the last time_pIs a proportionality coefficient, K_iIs the integral coefficient, K_dIs an integral coefficient;

and/or the formula of the second PID algorithm is as follows:

u′_n＝u′_n-1+Δu′

Δu′＝K_p*(e′_n-e′_n-1)+K_i*e′_n+K_d*(e′_n-2e′_n-1+e′_n-2)

wherein u'_nIs the current final purge flow, u'_n-1Delta u ' for the last final purge flow, delta u ' is the increment of the final purge flow, e '_nIs the current second deviation value, e'_n-1Is the second deviation value of, e 'of the previous time'_n-2The second deviation value, K, before the last time_pIs a proportionality coefficient, K_iIs the integral coefficient, K_dIs an integral coefficient.

Optionally, before the purging the chamber with the final purge flow, further comprising:

when the difference value between the current final purge flow and the last final purge flow is smaller than or equal to a preset threshold value, replacing the current final purge flow with the last final purge flow.

Optionally, before the purging the chamber with the final purge flow, further comprising:

filtering the final purge flow value by adopting the following formula:

y_n＝a₁*y_dn+a₂*y_n-1+a₁*y_n-2

wherein, y_nThe final purge flow value, y, for this output_dnFor the final purge flow value, y, without filtering_n-1The final purge flow value, y, output for the last time_n-2The final purge flow value, a, output for the previous time₁As filter parameters, a₂Are filter parameters.

Optionally, the acquiring the target oxygen content of the loading and unloading chamber includes:

obtaining the target oxygen content according to the following formula:

s'_mainWhen < sv-d, s_main＝s′_main+t*rate；

S'_mainWhen > sv-d, s_main＝s′_main-t*rate；

In sv-d < s'_mainWhen < sv + d, s_main＝sv；

Wherein s is_mainIs the target oxygen content, s'_mainFor the currently set oxygen content, sv is the input oxygen content, d is the deviation between the currently set oxygen content and the input oxygen content, t is the calculation period, and rate is the step rate.

Optionally, the converting the pressure value into a reference purge flow according to the pressure-flow conversion coefficient includes:

limiting the pressure value in an interval to obtain the pressure value after the interval is limited;

and converting the pressure value after interval limitation into the reference purge flow according to the pressure flow conversion coefficient.

Optionally, the interval defining the pressure value includes:

updating the pressure value to a first pressure threshold if the pressure value is greater than the first pressure threshold;

updating the pressure value to a second pressure threshold if the pressure value is less than the second pressure threshold;

wherein the second pressure threshold is less than the first pressure threshold.

Optionally, the load and unload chamber is purged with an inert gas.

A semiconductor thermal processing apparatus, comprising: a controller and a loading and unloading chamber, wherein the loading and unloading chamber is provided with a detection device and a purging device, wherein,

the detection device is used for detecting the oxygen content and the pressure value in the loading and unloading chamber;

the controller is used for acquiring the current target oxygen content and the detected oxygen content of the loading and unloading chamber; determining a first deviation value according to the detected oxygen content and the target oxygen content; determining an initial purge flow according to the first deviation value; acquiring a pressure-flow conversion coefficient and a current pressure value of the cavity, and converting the pressure value into a reference purge flow according to the pressure-flow conversion coefficient; determining a second deviation value according to the initial purge flow and the reference purge flow; and determining a final purging flow according to the second deviation value, and purging the loading and unloading cavity by adopting the final purging flow to control the purging device so as to control the oxygen content.

The embodiment of the invention has the following advantages:

in the embodiment of the invention, by acquiring the current target oxygen content of the loading and unloading chamber and detecting the oxygen content, determining a first deviation value according to the detected oxygen content and the target oxygen content, determining an initial purge flow according to the first deviation value, then the pressure flow conversion coefficient and the current pressure value of the loading and unloading chamber can be obtained, the pressure value is converted into the reference purging flow according to the pressure flow conversion coefficient, determining a second deviation value according to the initial purge flow and the reference purge flow, determining a final purge flow according to the second deviation value, purging the loading and unloading cavity by adopting the final purge flow, the oxygen content is controlled, the oxygen content in the self-adaptive cavity is controlled in a variable mode, the oxygen content and the pressure value in the cavity are considered, the accuracy and timeliness of the oxygen content control in the cavity are improved, and the processing quality of the semiconductor is guaranteed.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

FIG. 1a is a schematic diagram of the variation of oxygen content provided by an embodiment of the present invention;

FIG. 1b is a schematic representation of another variation in oxygen content provided by an embodiment of the present invention;

FIG. 1c is a schematic representation of another variation in oxygen content provided by an embodiment of the present invention;

FIG. 2 is a flowchart illustrating steps of a method for controlling oxygen content in a load/unload chamber of a semiconductor thermal processing apparatus according to an embodiment of the present invention;

FIG. 3 is a flowchart illustrating steps in a method for controlling oxygen content in a load lock chamber of a semiconductor thermal processing apparatus according to another embodiment of the present invention;

FIG. 4 is a schematic diagram of a PID control provided in accordance with an embodiment of the invention;

FIG. 5 is a schematic diagram of another PID control provided by an embodiment of the invention;

FIG. 6a is a schematic representation of another variation in oxygen content provided by an embodiment of the present invention;

FIG. 6b is a schematic representation of another variation in oxygen content provided by an embodiment of the present invention;

FIG. 6c is a schematic representation of another variation in oxygen content provided by an embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In practical application, two modes of large flow oxygen control and small flow oxygen control can be set, for example, the large flow oxygen control MFC adopts 1000SLM/Min inert gas, the exhaust valve is opened, the small flow oxygen control MFC adopts 500SLM/Min inert gas, and the exhaust valve is closed.

In the oxygen control process of a loading and unloading chamber for loading and/or unloading silicon wafers, as shown in fig. 1a, the ordinate is the oxygen content (LA oxygen content) of the chamber, the abscissa is time (T), the curve represents the relationship between the oxygen content and the time, the oxygen content is 10ppm as a target value, which can meet the process requirement, and the oxygen content is 800ppm as the upper limit of a small flow oxygen control window, specifically:

region: the oxygen content in the chamber is atmospheric oxygen content at the beginning, and large-flow oxygen control is adopted, so that the atmospheric oxygen content is changed to micro-oxygen content of 10 ppm.

Area II: in the transmission process of the silicon wafer, because the wafer transferring opening or the lifting boat is opened, oxygen enters the chamber, the oxygen content is changed from 10ppm less than the micro oxygen content to 800ppm, and the small flow oxygen control is adopted.

Area III: when the oxygen content is more than 800ppm, adopting large flow oxygen control until the oxygen content returns to 10 ppm.

And fourthly, switching to control oxygen at a small flow rate when the oxygen content is less than or equal to 10ppm, and gradually approaching 5 ppm.

However, the above method is a hysteresis window control mode, that is, only when a certain critical point is reached, one of the flow rates is selected for oxygen control, which is relatively solid and difficult to adapt to the change in the chamber in time, and specifically, there are at least the following disadvantages:

1. waste inert gas flow

In the case of a good seal, the target oxygen level is 10ppm, the fixed small flow rate oxygen control is 500SLM/min, which blows the oxygen level to 5ppm or less, the 10ppm oxygen level required by the process is maintained, the actually required flow rate is less than 500SLM/min, resulting in wasted inert gas flow rate.

As shown in FIG. 1b, the left ordinate represents the oxygen content, the right ordinate represents the inert gas flow rate, the abscissa represents time, the broken line represents the change in oxygen content with time, and the solid line represents the output change in inert gas flow rate.

When the oxygen content (dotted line) reaches 10ppm, the inert gas flow (solid line) is switched from 1000SLM/min to 500SLM/min and is kept unchanged, the oxygen content is finally kept at about 3ppm, the inert gas flow exceeds the actual demand, the actual demand inert gas flow is less than 500SLM/min, and the process target is kept at about 10 ppm.

2. When the oxygen content suddenly changes, the oxygen cannot be recovered in time

Because the oxygen content is less than 800ppmm, the inert gas flow rate is kept constant at a fixed small flow rate, the inert gas purging effect cannot offset the oxygen content rising speed, and the oxygen content cannot be quickly recovered to the process requirement.

As shown in FIG. 1c, the left ordinate represents the oxygen content, the right ordinate represents the inert gas flow rate, the abscissa represents time, the broken line represents the change in oxygen content with time, and the solid line represents the output change in inert gas flow rate.

Wherein, the oxygen content is at the position of a point, the machine station rises, and the oxygen content continuously rises because the inert gas flow rate is kept unchanged at 500 SLM/min; until point c, the oxygen content is more than 800ppm, and the inert gas flow is switched to 1000 SLM/min; under the inert gas purging of 1000SLM/min, the oxygen content of the loading and unloading chamber is gradually reduced until the b point position, the oxygen content is recovered to 10ppm, and the inert gas flow is switched to 500 SLM/min.

3. Under the condition of imperfect sealing or small target value of oxygen content, the technological requirements are difficult to meet

In the case of imperfect sealing or a small target value of oxygen content, due to a fixed inert gas flow rate mode, timely inert gas flow rate adjustment cannot be made according to the change of the oxygen content, and inert gas purging cannot reduce the oxygen content to be lower, so that the oxygen content cannot meet the process requirement.

Based on this, the embodiment of the invention provides that by acquiring the current target oxygen content of the loading and unloading chamber and detecting the oxygen content, determining a first deviation value according to the detected oxygen content and the target oxygen content, determining an initial purge flow according to the first deviation value, then the pressure flow conversion coefficient and the current pressure value of the loading and unloading chamber can be obtained, the pressure value is converted into the reference purging flow according to the pressure flow conversion coefficient, determining a second deviation value according to the initial purge flow and the reference purge flow, determining a final purge flow according to the second deviation value, purging the loading and unloading cavity by adopting the final purge flow, the oxygen content is controlled, the oxygen content in the self-adaptive cavity is controlled in a variable mode, the oxygen content and the pressure value in the cavity are considered, the accuracy and timeliness of the oxygen content control in the cavity are improved, and the processing quality of the semiconductor is guaranteed.

Referring to fig. 2, a flowchart illustrating steps of a method for controlling oxygen content in a loading/unloading chamber of a semiconductor thermal processing apparatus according to an embodiment of the present invention is provided, which may specifically include the following steps:

step 201, acquiring the current target oxygen content and the detected oxygen content of a loading and unloading chamber;

in the process of controlling the oxygen content of the loading and unloading chamber, the currently set target oxygen content can be obtained to be used as the target of controlling the current oxygen content, and in order to adapt to the change of the oxygen content in the loading and unloading chamber in time, the oxygen content of the loading and unloading chamber can be detected in real time to obtain the current detected oxygen content.

In an embodiment of the present invention, an initially input oxygen content value (i.e., a final target of oxygen content control) may be obtained, and then a step-wise algorithm may be used to set the oxygen content (i.e., set the target oxygen content), so as to gradually reach the target at a certain rate, thereby avoiding a drastic change in output due to an excessively large adjustment difference.

Based on this, obtaining the target oxygen content of the loadlock chamber may include:

obtaining the target oxygen content according to the following formula:

s'_mainWhen < sv-d, s_main＝s′_main+t*rate；

S'_mainWhen > sv-d, s_main＝s′_main-t*rate；

In sv-d < s'_mainWhen < sv + d, s_main＝sv；

Wherein, s'_mainFor the currently set oxygen content, s_mainFor a target oxygen content (i.e. as the oxygen content to be set), sv is the initially input oxygen content, d is the deviation between the currently set oxygen content and the initially input oxygen content, t is a preset calculation period, and rate is a preset step rate.

In a specific implementation, the input initial oxygen content sv may be obtained, and the currently set oxygen content s 'may be obtained'_mainAt the currently set oxygen content s'_mainWith a smaller deviation from the initially input oxygen content sv, i.e. the currently set oxygen content s'_mainWithin the sv + -d range, the current target oxygen content s is determined_mainEqual to the initial oxygen content sv.

At the currently set oxygen content s'_mainWhen the deviation from the initially input oxygen content sv is large, namely the currently set oxygen content s'_mainOutside the sv + -d range, then the oxygen content s 'at the current setting'_mainOn the basis, the input oxygen content sv is approached in steps at a rate to determine the target oxygen content s in the process_main。

Step 202, determining a first deviation value according to the detected oxygen content and the target oxygen content;

in order to minimize the deviation between the current detected oxygen content and the target oxygen content in the chamber, the difference between the detected oxygen content and the target oxygen content may be determined, resulting in a first deviation value.

Step 203, determining an initial purge flow according to the first deviation value;

after the current first deviation value is obtained, the deviation of the oxygen content in the chamber is obtained, and then the initial purge flow rate of the inert gas for purging the chamber can be obtained according to the deviation of the oxygen content.

Step 204, acquiring a pressure-flow conversion coefficient and a current pressure value of the loading and unloading chamber, and converting the pressure value into a reference purge flow according to the pressure-flow conversion coefficient;

in order to take account of the pressure value in the cavity and ensure the reliable operation of the micro-positive pressure system under the condition of good micro-oxygen control, the pressure in the cavity can be measured in real time, and then the current pressure value is obtained, and the pressure value can be converted into the reference purging flow for the inert gas used for purging the cavity according to the preset pressure flow conversion coefficient, so that the reference purging flow can be compared with the initial purging flow in the same interval range.

Specifically, a pressure-flow conversion coefficient can be set according to the relation between the demand range of the pressure value of the machine table, the pressure value and the purging flow, so that the converted pressure value can be compared with the initial purging flow, and if the range of the initial purging flow is 0-1000.0, the pressure value needs to be in the range after conversion.

For example, in the standardIn the machine, the ideal pressure range is 3000mtorr +/-1000 mtorr, if the pressure value (xt) of 3000mtorr corresponds to the purge flow (yt) of 500SLM/min, the reference value of the proportion k is obtained according to the corresponding relation, and the formula is adoptedK is 1/6.

In an embodiment of the present invention, converting the pressure value into the reference purge flow according to the pressure-flow conversion coefficient may include:

limiting the pressure value in an interval to obtain the pressure value after the interval is limited; and converting the pressure value after the interval limitation into a reference purging flow according to the pressure flow conversion coefficient.

In an embodiment of the present invention, the interval limitation of the pressure values includes:

updating the pressure value to a first pressure threshold value when the pressure value is greater than the first pressure threshold value; under the condition that the pressure value is smaller than the second pressure threshold value, updating the pressure value to the second pressure threshold value;

wherein the second pressure threshold is less than the first pressure threshold.

In practical applications, a pressure threshold range composed of a first pressure threshold and a second pressure threshold may be set, and in the case that the pressure value is greater than the first pressure threshold, the pressure value may be updated to the first pressure threshold (the upper limit of the pressure threshold range), and in the case that the pressure value is less than the second pressure threshold, the pressure value may be updated to the second pressure threshold (the lower limit of the pressure threshold range), as shown in the following formula:

wherein x is_jFor the pressure value after interval definition, x_pIs an initial pressure value, n is a first pressure threshold value, and m is a second pressure threshold value.

Step 205, determining a second deviation value according to the initial purge flow and the reference purge flow;

after the initial purge flow and the reference purge flow are obtained, the two may be compared to obtain a second deviation value, i.e., a deviation value for the purge flow of the inert gas.

And step 206, determining a final purging flow according to the second deviation value, and purging the loading and unloading cavity by adopting the final purging flow so as to control the oxygen content.

Wherein the loadlock chamber is purged with an inert gas, such as high purity nitrogen.

After the second deviation value is obtained, the final purging flow can be determined according to the second deviation value, the final purging flow is output as an MFC, inert gas can be filled into the cavity according to the final purging flow to purge the cavity, oxygen is discharged out of the cavity, the oxygen content of the cavity meets the process requirement, the micro-positive pressure of the cavity is kept, the external air can be effectively prevented from entering the cavity through the micro-positive pressure, and the oxygen content control effect is guaranteed.

In an embodiment of the present invention, in order to avoid a problem of a peak generated when the output final purge flow has a sudden step change, and ensure a smooth output of the flow, a filter output may be designed to smooth the output flow value, and before purging the chamber with the final purge flow, the method further includes:

and (3) filtering the final purge flow value by adopting the following formula:

y_n＝a₁*y_dn+a₂*y_n-1+a₁*y_n-2

wherein, y_nFor the final purge flow value, y, of this output_dnFor final purge flow values without filtering, y_n-1Final purge flow value, y, for last output_n-2Final purge flow value, a, output for the previous time₁As filter parameters, a₂Are filter parameters.

In an embodiment of the present invention, in order to prevent frequent changes in the output final purge flow, before purging the chamber with the final purge flow, the method may further include:

and when the difference value between the current final purge flow and the last final purge flow is smaller than or equal to a preset threshold value, replacing the current final purge flow with the last final purge flow.

Specifically, if the difference between the current final purge flow and the last output final purge flow is less than or equal to the preset threshold, the last output final purge flow is used to replace the current final purge flow, that is, the last output final purge flow is maintained unchanged, and only when the difference between the current final purge flow and the last output final purge flow is greater than the preset threshold, the current final purge flow is output, as shown in the following formula:

where y (n) is the current final purge flow, y (n-1) is the last final purge flow, and y0 is a preset threshold.

In the embodiment of the invention, by acquiring the current target oxygen content of the loading and unloading chamber and detecting the oxygen content, determining a first deviation value according to the detected oxygen content and the target oxygen content, determining an initial purge flow according to the first deviation value, then the pressure flow conversion coefficient and the current pressure value of the loading and unloading chamber can be obtained, the pressure value is converted into the reference purging flow according to the pressure flow conversion coefficient, determining a second deviation value according to the initial purge flow and the reference purge flow, determining a final purge flow according to the second deviation value, purging the loading and unloading cavity by adopting the final purge flow, the oxygen content is controlled, the oxygen content in the self-adaptive cavity is controlled in a variable mode, the oxygen content and the pressure value in the cavity are considered, the accuracy and timeliness of the oxygen content control in the cavity are improved, and the processing quality of the semiconductor is guaranteed.

Referring to fig. 3, a flowchart illustrating steps of another method for controlling oxygen content in a loading/unloading chamber of a semiconductor thermal processing apparatus according to an embodiment of the present invention is provided, which may specifically include the following steps:

301, acquiring the current target oxygen content and the detected oxygen content of the loading and unloading chamber;

step 302, determining a first deviation value according to the detected oxygen content and the target oxygen content;

step 303, calculating by adopting a preset first PID algorithm based on the current first deviation value and the historical first deviation value, and determining an initial purge flow;

in order to achieve better control effect, a feed-forward cascade PID (proportional integral differential) control based on an oxygen content value and a pressure value can be adopted, as shown in fig. 4, a main control and a secondary control are set, a feedback value (namely, detected oxygen content) and an oxygen content setting value (namely, target oxygen content) are used as input of the main control, the main control calculates output according to a difference value (namely, a first deviation value) between the feedback value and the oxygen content setting value, the output of the main control and a pressure value subjected to proportional conversion are used as input of the secondary control, the secondary control calculates output according to the output of the main control and the pressure value subjected to proportional conversion, and the output of the MFC is equal to the output of the secondary control.

In a specific implementation, an incremental PID may be applied, where the incremental PID is a recursive algorithm, and a difference value between a control amount at a current time and a control amount at a previous time is used as a new control amount.

As an example, the first PID algorithm has the formula:

u_n＝u_n-1+Δu

Δu＝K_p*(e_n-e_n-1)+K_i*e_n+K_d*(e_n-2e_n-1+e_n-2)

wherein u is_nFor the current initial purge flow, u_n-1For the last initial purge flow, Δ u is the increment from the initial purge flow, e_nIs the current first deviation value, e_n-1The last first deviation value, e_n-2Is the first deviation value before the last time, K_pIs a proportionality coefficient, K_iIs the integral coefficient, K_dIs an integral coefficient.

Step 304, acquiring a pressure-flow conversion coefficient and a current pressure value of the loading and unloading chamber, and converting the pressure value into a reference purge flow according to the pressure-flow conversion coefficient;

305, determining a second deviation value according to the initial purge flow and the reference purge flow;

step 306, calculating by adopting a preset second PID algorithm based on the current second deviation value and the historical second deviation value, and determining the final purge flow;

in a specific implementation, an incremental PID may be applied, where the incremental PID is a recursive algorithm, and a difference value between a control amount at a current time and a control amount at a previous time is used as a new control amount.

As an example, the second PID algorithm is formulated as:

u′_n＝u′_n-1+Δu′

Δu′＝K_p*(e′_n-e′_n-1)+K_i*e′_n+K_d*(e′_n-2e′_n-1+e′_n-2)

wherein u'_nIs the current final purge flow, u'_n-1Delta u 'is the increment of the final purge flow, e'_nIs the current secondary deviation value, e'_n-1Is the last second deviation value, e'_n-2Is the second deviation value before the last time, K_pIs a proportionality coefficient, K_iIs the integral coefficient, K_dIs an integral coefficient.

And 307, purging the loading and unloading chamber by adopting the final purging flow so as to control the oxygen content.

An embodiment of the invention is illustrated below with reference to fig. 5:

1. and (3) PID control of a main control loop: setting the value s by the oxygen content_main(i.e., target oxygen)Calculating the difference e (n) x (n) -s between the content and the feedback value x (n) (i.e. the detected oxygen content)_main(i.e., first offset value), and then the main control output y can be obtained through PID operation_mainU (i.e., initial purge flow), with an output in the range of 0.0-1000.0.

2. And (3) secondary control loop PID control: the pressure value is used as a feedforward value, the main control output is used as a secondary control input value, and the main control output is used as a secondary control set value s_assist＝y_mainAnd the current pressure value is used as a secondary control input x after interval limitation and proportion conversion_iComparing it with the master control output to obtain the difference e (n) s_assist-x_i(i.e., the second deviation value), and then PID operation can be performed to obtain the inert gas flow y of the secondary control output_assist＝u(i.e., final purge flow), and a final output range of 0.0-1000.0 SLM/min.

Wherein, the pressure value is greater than n (interval upper limit), and is processed according to n, and the pressure value is less than m (interval lower limit), and is processed according to m. The pressure value after the interval limitation can be converted according to the proportion k.

Specifically, the conversion parameters can be adjusted according to the relation between the demand range of the pressure value of the machine table, the pressure value and the sweeping flow, so that the converted pressure value can be compared with the initial sweeping flow, and if the current initial sweeping flow range is 0-1000.0, the pressure value needs to be in the range after conversion.

For example, in a standard machine, the ideal pressure range is 3000mtorr ± 1000mtorr, if the pressure value (xt) of 3000mtorr corresponds to the inert gas flow (yt) of 500SLM/min, the reference value of the ratio k is obtained according to the corresponding relationship, and the formula is shown as followsK is 1/6.

The embodiment of the invention at least has the following effects:

1. saving inert gas flow

In the case of good sealing, when the process is to be started, the oxygen content of the chamber needs to be controlled to a target value, so that the effect of saving the gas flow can be achieved.

As shown in fig. 6a, the ordinate represents the oxygen content, the right ordinate represents the inert gas flow rate, the abscissa represents time, the broken line represents the change in the oxygen content with time, and the solid line represents the output change in the inert gas flow rate.

Wherein, the target value is 10ppm, the oxygen content is kept at 10 +/-1 ppm after the target value is reached, and finally the inert gas flow is stabilized at 400SLM/min through PID adjustment, so that compared with a fixed flow pattern of 500SLM/min, the inert gas flow of 100SLM/min is saved.

2. Can be recovered in time when the oxygen content is suddenly changed

When the oxygen content is stable, if the oxygen content in the chamber changes suddenly, for example, in the process of lifting the boat or opening the wafer opening, the oxygen enters the chamber, the oxygen content increases suddenly, the change can be tracked quickly, the output is adjusted, and the oxygen content is recovered to the process requirement range.

As shown in fig. 6b, the ordinate represents the oxygen content, the right ordinate represents the inert gas flow rate, the abscissa represents time, the broken line represents the change in the oxygen content with time, and the solid line represents the output change in the inert gas flow rate.

Wherein the target value is 10ppm, and the oxygen content is maintained at 10. + -.1 ppm after the target value is reached. The point a is that a boat lifting or a sheet conveying port is opened on a machine station, oxygen enters a loading and unloading chamber from a sheet box, the oxygen content rises, the flow of inert gas changes along with the change, and the oxygen content is recovered to about 11ppm (point b) through about 15min from 610SLM/min to 1000SLM/min and is maintained at 10 +/-1 ppm all the time.

3. Under the condition of imperfect sealing or small target value of oxygen content, the process requirement can be met

When the sealing condition of the equipment is not good, the oxygen content of the loading and unloading chamber needs to be controlled at a target value, and the oxygen content can reach the index meeting the process requirement by increasing the flow.

As shown in fig. 6c, the ordinate represents the oxygen content, the right ordinate represents the inert gas flow rate, the abscissa represents time, the broken line represents the change in the oxygen content with time, and the solid line represents the output change in the inert gas flow rate.

Wherein the target value is 5ppm, the oxygen content is kept at 5 +/-1 ppm after the target value is reached, the flow rate of the inert gas is from 992SLM/min to 510SLM/min, and finally the flow rate is maintained at about 690 SLM/min; and point a is output when the target value is reached, and the inert gas flow is output stably when suddenly changed.

It should be noted that, for simplicity of description, the method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the present invention is not limited by the illustrated order of acts, as some steps may occur in other orders or concurrently in accordance with the embodiments of the present invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no particular act is required to implement the invention.

An embodiment of the present invention provides a semiconductor heat treatment apparatus, including: the device comprises a controller and a loading and unloading chamber, wherein a detection device and a purging device are arranged on the loading and unloading chamber.

The detection device is used for detecting the oxygen content and the pressure value in the loading and unloading chamber;

the controller is used for acquiring the current target oxygen content and the detected oxygen content of the loading and unloading chamber; determining a first deviation value according to the detected oxygen content and the target oxygen content; determining an initial purge flow according to the first deviation value; acquiring a pressure-flow conversion coefficient and a current pressure value of the cavity, and converting the pressure value into a reference purge flow according to the pressure-flow conversion coefficient; determining a second deviation value according to the initial purge flow and the reference purge flow; and determining a final purging flow according to the second deviation value, and purging the loading and unloading cavity by adopting the final purging flow to control the purging device so as to control the oxygen content.

In an embodiment of the present invention, the determining the initial purge flow according to the first deviation value includes:

calculating by adopting a preset first PID algorithm based on the current first deviation value and the historical first deviation value, and determining the initial purge flow;

determining a final purge flow based on the second deviation value comprises:

and calculating by adopting a preset second PID algorithm based on the current second deviation value and the historical second deviation value, and determining the final purge flow.

In an embodiment of the present invention, the formula of the first PID algorithm is:

u_n＝u_n-1+Δu

Δu＝K_p*(e_n-e_n-1)+K_i*e_n+K_d*(e_n-2e_n-1+e_n-2)

wherein u is_nFor the current initial purge flow, u_n-1Δ u is the increment of the initial purge flow, e_nIs the current first deviation value, e_n-1The first deviation value of the last time, e_n-2Is the first deviation value, K, before the last time_pIs a proportionality coefficient, K_iIs the integral coefficient, K_dIs an integral coefficient;

and/or the formula of the second PID algorithm is as follows:

u′_n＝u′_n-1+Δu′

Δu′＝K_p*(e′_n-e′_n-1)+K_i*e′_n+K_d*(e′_n-2e′_n-1+e′_n-2)

wherein u'_nIs the current final purge flow, u'_n-1Delta u ' for the last final purge flow, delta u ' is the increment of the final purge flow, e '_nIs the current second deviation value, e'_n-1Is the second deviation value of, e 'of the previous time'_n-2The second deviation value, K, before the last time_pIs a proportionality coefficient, K_iIs the integral coefficient, K_dIs an integral coefficient.

In an embodiment of the present invention, before the purging the chamber with the final purge flow, the method further includes:

when the difference value between the current final purge flow and the last final purge flow is smaller than or equal to a preset threshold value, replacing the current final purge flow with the last final purge flow.

In an embodiment of the present invention, before the purging the chamber with the final purge flow, the method further includes:

filtering the final purge flow value by adopting the following formula:

y_n＝a₁*y_dn+a₂*y_n-1+a₁*y_n-2

wherein, y_nThe final purge flow value, y, for this output_dnFor the final purge flow value, y, without filtering_n-1The final purge flow value, y, output for the last time_n-2The final purge flow value, a, output for the previous time₁As filter parameters, a₂Are filter parameters.

In an embodiment of the present invention, the acquiring the target oxygen content of the loading and unloading chamber includes:

obtaining the target oxygen content according to the following formula:

s'_mainWhen < sv-d, s_main＝s′_main+t*rate；

S'_mainWhen > sv-d, s_main＝s′_main-t*rate；

In sv-d < s'_mainWhen < sv + d, s_main＝sv；

Wherein s is_mainIs the target oxygen content, s'_mainFor the currently set oxygen content, sv is the input oxygen content, d is the deviation between the currently set oxygen content and the input oxygen content, t is the calculation period, and rate is the step rate.

In an embodiment of the present invention, the converting the pressure value into the reference purge flow according to the pressure-flow conversion coefficient includes:

limiting the pressure value in an interval to obtain the pressure value after the interval is limited;

and converting the pressure value after interval limitation into the reference purge flow according to the pressure flow conversion coefficient.

In an embodiment of the present invention, the performing interval limitation on the pressure values includes:

updating the pressure value to a first pressure threshold if the pressure value is greater than the first pressure threshold;

updating the pressure value to a second pressure threshold if the pressure value is less than the second pressure threshold;

wherein the second pressure threshold is less than the first pressure threshold.

In one embodiment of the invention, the load and unload chamber is purged with an inert gas.

In the embodiment of the invention, by acquiring the current target oxygen content of the loading and unloading chamber and detecting the oxygen content, determining a first deviation value according to the detected oxygen content and the target oxygen content, determining an initial purge flow according to the first deviation value, then the pressure flow conversion coefficient and the current pressure value of the loading and unloading chamber can be obtained, the pressure value is converted into the reference purging flow according to the pressure flow conversion coefficient, determining a second deviation value according to the initial purge flow and the reference purge flow, determining a final purge flow according to the second deviation value, purging the loading and unloading cavity by adopting the final purge flow, the oxygen content is controlled, the oxygen content in the self-adaptive cavity is controlled in a variable mode, the oxygen content and the pressure value in the cavity are considered, the accuracy and timeliness of the oxygen content control in the cavity are improved, and the processing quality of the semiconductor is guaranteed.

An embodiment of the present invention further provides an electronic device, which may include a processor, a memory, and a computer program stored in the memory and capable of being executed on the processor, wherein the computer program, when executed by the processor, implements the method for controlling the oxygen content in the load/unload chamber of the semiconductor thermal processing apparatus.

An embodiment of the present invention also provides a computer-readable storage medium on which a computer program is stored, the computer program, when executed by a processor, implementing the method for controlling oxygen content in a load/unload chamber of an upper semiconductor thermal processing apparatus.

For the device embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, refer to the partial description of the method embodiment.

The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

Embodiments of the present invention are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing terminal to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing terminal to cause a series of operational steps to be performed on the computer or other programmable terminal to produce a computer implemented process such that the instructions which execute on the computer or other programmable terminal provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the embodiments of the invention.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.

The semiconductor thermal processing equipment and the method for controlling the oxygen content in the loading and unloading chamber thereof are described in detail, and the principle and the embodiment of the invention are explained by applying specific examples, and the description of the examples is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.