1. A method of charged particle beam processing a workpiece, comprising:

placing a workpiece in a vacuum chamber;

directing a gas to the region of interest, the gas being adsorbed to the surface of the workpiece without reacting;

directing a beam of non-reactive clusters toward a region of interest in the vacuum chamber, the beam depositing energy into the region of interest to cause decomposition of an adsorbed gas in the region of interest, the adsorbed gas decomposing to form volatile compounds and non-volatile compounds deposited on the surface; directing the bound particle beam in the same vacuum chamber to an area on the workpiece where material is deposited to process the workpiece;

directing a beam of atomic or molecular clusters toward a region of interest on the workpiece includes directing a cluster beam comprising carbon, gold, bismuth or xenon, C₆₀，C₇₀，C₈₀，C₈₄，Au₃，Bi₃Or Xe₄₀Cluster bundle of (2).

2. The method of claim 1, wherein directing a gas to the region of interest comprises directing a precursor gas comprising a silane compound or an organometallic compound that decomposes clusters in the presence of the beam to deposit a material onto the surface of the workpiece, wherein directing a precursor gas to the region of interest comprises directing a gas comprising Tetramethylorthosilicate (TMOS), Tetraethylorthosilicate (TEOS), tetrabutoxysilane, Si (OC), and a combination thereof₄H₉)₄Acetylacetonato-dimethyl-gold, tungsten hexacarbonyl (W (CO))₆) Or methylcyclopentadienyl trimethylplatinum (C)₉H₁₆Pt) the precursor gas decomposes in the case of a cluster beam, thereby depositing material onto the workpiece surface.

3. The method of claim 1, wherein directing a beam of atomic or molecular clusters toward a region of interest on the workpiece comprises: directing a beam from a cluster of plasma ion sources; directing the cluster beam from the plasma ion source includes directing the cluster beam from an inductively coupled plasma ion source; directing the charged particle beam includes directing a focused ion beam or electron beam.

4. A method of processing a charged particle beam, comprising: placing a workpiece in a vacuum chamber; directing a beam of atomic or molecular clusters toward a region of interest on a workpiece to deposit a material onto a surface of the workpiece within a vacuum chamber;

preventing the beam of atomic or molecular clusters from impinging on the workpiece; and after depositing the material on the surface of the work piece, directing the focused ion beam toward a target area of the deposited material within the same vacuum chamber to mill the work piece;

wherein directing a beam of atomic or molecular clusters toward a region of interest on the workpiece comprises directing a beam comprising carbon. The fullerene beam is directed. Directing a bundle of clusters comprising carbon, gold, or bismuth;

directing a precursor gas toward the region of interest prior to directing the cluster beam; and wherein the cluster beam deposits energy into the region of interest to induce a deposition reaction in the region of interest.

5. The method of claim 4, wherein directing a beam of atomic or molecular clusters to a region of interest on the workpiece to deposit material onto the workpiece surface comprises depositing a material comprising the clusters.

Wherein directing a cluster beam of atoms or molecules toward a region of interest on the workpiece comprises: directing a cluster beam from an evaporated cluster source;

directing a beam of atomic or molecular clusters toward a region of interest on the workpiece comprises: directing a beam from a cluster of plasma ion sources; directing the cluster beam from the plasma ion source includes directing the cluster beam from an inductively coupled plasma ion source.

6. A charged particle beam system, comprising: a vacuum chamber; a charged particle beam column for directing a focused, non-agglomerated particle beam toward a workpiece within a vacuum chamber for processing; a workpiece support for supporting a workpiece within the vacuum chamber; a cluster ion source for directing a primary beam of charged clusters to a workpiece within a vacuum chamber; and a gas injection system for providing a gas on the surface of the workpiece in the vicinity of the region of interest, the gas being adsorbed onto the surface and chemically reacted only in the presence of the charged cluster beam.

The cluster ion source comprises a plasma ion source.

The plasma ion source comprises an inductively coupled plasma ion source.

The cluster ion source comprises a fullerene source.

The cluster ion source comprises a bismuth, gold or xenon cluster source.

7. The charged particle beam system of claim 6 in which the chemical reaction comprises decomposition of the gas to cause deposition of material from the gas onto the region of interest.

8. The charged particle beam system of claim 6 in which the chemical reaction comprises decomposition of the gas and decomposition of clusters in the beam to cause material from the gas and the beam to deposit onto the region of interest.

9. The method of claim 6, wherein the chemical reaction comprises decomposition of the gas to cause etching of the region of interest.

10. The method of claim 6, wherein directing a beam of clusters of atoms or molecules to the region of interest comprises directing a beam of clusters from a plasma chamber.

Background

Charged particle beams (e.g., ion beams and electron beams) are used for workpiece processing in nanotechnology because charged particle beams form very small spots. For example, focused ion beam systems are capable of imaging, milling, deposition and analysis with sub-micron accuracy. Focused ion beam systems are commercially available from FEI corporation of hilsburler, oregon, for example, the assignee of the present application. The ions may be used to sputter (i.e., physically eject) material from the workpiece to create features, such as trenches, on the workpiece. The ion beam may also be used to activate etchant gases to enhance sputtering, or to decompose precursor gases to deposit material near the ion beam impact point. The ion beam may also be used to form an image of the workpiece by collecting secondary particles ejected as a result of impact by the ion beam. The number of secondary particles ejected from each point on the surface is used to determine the brightness of the image at the corresponding point on the image. Focused ion beams are commonly used in the semiconductor industry. In one application, for example, a focused ion beam is used to cut small trenches into integrated circuits to expose cross sections of vertical structures for observation or measurement using an ion beam or an electron beam.

Electron beams may also be used to process workpieces. Electron beam processing is described, for example, in U.S. Pat. No.6,753,538Mucil et al. For "electron beam processing". In a process known as electron microscopy, an electron beam is typically used to form an image. Electron microscopes have higher resolution and greater depth of focus than optical microscopes. In a Scanning Electron Microscope (SEM), the primary electron beam is focused to a thin spot that scans the surface to be observed. Secondary electrons are emitted from the surface when struck by the primary electron beam. Secondary electrons are detected and an image is formed, the brightness of each point of the image being dependent on the number of secondary electrons detected when the electron beam hits the corresponding point on the surface.

In Transmission Electron Microscopy (TEM), a wide beam of electrons strikes a sample, and electrons transmitted through the sample are focused to form an image of the sample. The sample must be thin enough so that many of the electrons in the primary beam pass through the sample and exit at opposite locations. The samples are typically thinned to a thickness of less than 100 nm. A method of preparing a sample comprising: a thin sample is cut from a workpiece using a focused ion beam and then thinned using an ion beam.

In a Scanning Transmission Electron Microscope (STEM), a primary electron beam is focused to a thin spot, which is then scanned across the sample surface. The electrons transmitted through the workpiece are collected by an electron detector located on the other side of the sample, and the intensity of each point on the image corresponds to the number of electrons collected when the primary beam strikes the corresponding point on the surface.

When a discrete particle beam strikes a surface, the surface may be damaged or altered. Focused ion beam systems typically use gallium ions in a liquid metal gallium ion source. Gallium ions are relatively heavy and acceleration through gallium ions of typically 30,000 volts will inevitably alter the workpiece surface. Plasma ion systems, such as the system described in Keller et al W020050081940, "magnetic enhancement of focused ion beam systems, inductive coupling, plasma source". Lighter ions may be used, causing less damage, but these ions still typically alter the workpiece surface, which is incorporated by reference herein. Electrons, although much lighter than ions, also alter the working surface. When a user wishes to measure a workpiece with nanometer accuracy, workpiece variations caused by the impact of charged particles can be very significant, especially in softer materials such as photoresist, low-k and ultra-low-k dielectric materials such as polyphenylene materials.

Currently, technicians quantify the dimensional changes caused by charged particle beam deposition of the protective layer and then apply correction factors to subsequent measurements to obtain an estimate of the true dimensions. This estimation is not always accurate due to variations in the charged particle beam.

When a user wishes to extract a sample viewed by TEM using an ion beam, for example, U.S. patent No. 5270552 to Ohnishi et al. "sample separation methods and methods of sample separation method analysis methods typically involve a user scanning a focused ion beam in an imaging mode to locate a region of interest. Scanning can cause damage to the surface. The location of interest is found and the beam begins to mill the trench, the workpiece is additionally damaged since the edges of the beam are not sharp, i.e. the beam is generally gaussian shaped and the distribution of ions at the tail of the gaussian will damage not only the workpiece at the edges of the trench, but also relatively hard materials.

To protect the workpiece surface, a protective layer is typically applied prior to charged particle beam processing. One method of applying a protective layer is charged particle beam deposition, i.e., using a particle beam to provide energy to decompose a gas to deposit a material on a surface. The protective layer shields the area around the cut and preserves the characteristics of the feature to be imaged and measured. Common deposition gases include precursor compounds that decompose into tungsten, platinum, gold, and carbon. For example, tungsten hexacarbonyl can be used to deposit tungsten, methylcyclopentadienyltrimethylplatinum can be used to deposit platinum, and styrene can be used to deposit carbon. Precursor gases for depositing many different materials are known in the art. The preferred material to deposit as the protective layer depends on the application, including the composition of the underlying target surface and the interaction between the protective layer material and the target surface.

Although charged particle beam assisted deposition can locally apply the layer at the precise location where it is needed, there are some drawbacks to applying a protective layer using stray particle beam deposition. Charged particle beam assisted deposition is relatively slow and in some processes the deposition of the protective layer consumes 60% of the total process time. When an ion beam is initially scanned onto a target surface to deposit material, the ion beam will sputter material off the surface for an initial period of time until a sufficient amount of deposited material has accumulated to protect the surface from the ion beam.

Even though this time period may be small, it may be large enough to allow removal of a large amount of material, which may result in the accuracy of the cross-sectional analysis being compromised.

Electron and laser beams may be used to generate secondary electrons to decompose precursor gases to deposit a protective layer, but these beams may also damage the bottom surface when the beams are at sufficient energy and/or current density levels to achieve good processing times. The use of such beams is generally impractical because deposition is too slow if the beam is "weak" enough not to damage the underlying surface, and Physical Vapor Deposition (PVD) sputtering methods can be used to deposit protective layers in certain areas, but they are generally not useful for production control applications in wafer fabrication facilities because such methods cannot be used to locally apply a deposited layer to a target portion of the wafer surface. Patents assigned to the assignee of the present invention describe a PVD method that provides a localized layer, with a beam of charged particles used to sputter material from the target onto the surface, without the beam of charged particles being directed directly at the target. The surface itself avoids damage, but this method is time consuming.

Another method of applying a protective coating is described in U.S. patent No.6,926,935 to aijavec et al. In this method, the charged particle beam is not directed to the region of interest, but to a region outside the region of interest. The secondary electrons decompose the precursor gas on the target area to provide a protective layer. The charged particle beam may be moved inwards when creating a protective layer around the edge of the region of interest. This method is also time consuming.

Brush-coated colloidal silver has long been used to create conductive protective layers in scanning electron microscopes. The silver particles used are relatively large. Applying the layer using a brush may damage the substrate and may not provide a local layer.

Another method of applying a protective coating is to use a felt tip pen, such as a sharp brand pen from Rubbermaid corporation, Sanford division. The ink from the Sharpie pen is well suited for use in a vacuum chamber because it will dry out completely and there is little outgassing in the vacuum chamber. Touching the area of interest with a pen changes the surface, thus applying ink near the area of interest, which then wicks to the area of interest. Compounds in the ink may protect certain surfaces. The area affected by the felt tip is very large compared to the submicron features of modern integrated circuits and the positioning accuracy of the ink is insufficient.

Methods of using protective layers of fullerene molecules in computer disk drive components are described, for example, in U.S. patent No.6,743,481 to Hoehn et al. For "method of producing ultra-thin protective overcoats" and U.S. Pat. No.20020031615 to Dykes et al. Is used for the production process of the ultrathin protective layer. The fullerene is ejected from the source under the action of the ion beam or the electron beam, and some fullerene is ejected and coated in the direction of the target material.

There is a need in the industry for a method of quickly and accurately applying a local protective layer without damaging the surface of the workpiece.

Disclosure of Invention

It is an object of the present invention to use a cluster beam to deposit or etch a workpiece surface to reduce surface damage.

The technical scheme of the invention is that the method for processing the workpiece by the charged particle beam comprises the following steps:

placing a workpiece in a vacuum chamber;

directing a gas to the region of interest, the gas being adsorbed to the surface of the workpiece without reacting;

directing a beam of non-reactive clusters toward a region of interest in the vacuum chamber, the beam depositing energy into the region of interest to cause decomposition of an adsorbed gas in the region of interest, the adsorbed gas decomposing to form volatile compounds and non-volatile compounds deposited on the surface; the workpiece is processed by directing a beam of bound particles in the same vacuum chamber at the area of the workpiece where material is deposited.

Directing a beam of atomic or molecular clusters toward a region of interest on the workpiece includes directing a cluster beam comprising carbon, gold, bismuth or xenon, C₆₀，C₇₀，C₈₀，C₈₄，Au₃，Bi₃Or Xe₄₀Cluster bundle of (2).

Directing a gas to the region of interest includes directing a precursor gas including a silane compound or an organometallic compound that decomposes the cluster in the presence of the beam to deposit a material on the surface of the workpiece, wherein directing the precursor gas to the region of interest includes directing a gas including Tetramethylorthosilicate (TMOS), Tetraethylorthosilicate (TEOS), tetrabutoxysilane, Si (OC)₄H₉)₄Acetylacetonato-dimethyl-gold, tungsten hexacarbonyl (W (CO))₆) Or methylcyclopentadienyl trimethyl platinum (C)₉H₁₆Pt), the precursor gas is decomposed in the case of a cluster beam, thereby depositing material onto the workpiece surfaceThe above.

Advantageously, the invention includes the use of a cluster ion source to etch a surface or deposit a material. The use of clusters can generally reduce damage to the substrate compared to the use of a single ion. The invention is particularly useful for depositing protective layers for charged particle beam processing. In some embodiments, the precursor gas is decomposed by the cluster beam to deposit the protective layer. In other embodiments, the components of the clusters are deposited on the workpiece surface to provide a protective layer for charged particle beam processing. The invention is particularly useful for depositing protective layers for charged particle beam processing. Embodiments of the invention also include systems that allow for the deposition of protective layers using cluster sources and additional charged particle beam processing.

Drawings

For a further understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

fig. 1 shows a preferred embodiment of the system of the present invention comprising a plasma source capable of generating chain-like clusters of atoms and directing the clusters to a sample.

Figure 2 shows a preferred method according to the invention.

Figure 3 shows a preferred plasma cluster source.

Fig. 4 shows an alternative cluster source.

Detailed Description

The following is a detailed description of example embodiments of the invention depicted in the accompanying drawings. The details of the example embodiments are set forth in order to provide a clear conveyance of the invention. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; the invention is not limited to the disclosed embodiments. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. The following detailed description is designed to make such embodiments obvious to a person of ordinary skill in the art.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

In some embodiments of the invention, the cluster provides energy to decompose the precursor gases to deposit the layer while minimizing damage to the workpiece surface. The cluster can also be used to etch the workpiece surface, optionally with an etch enhancing gas. In other embodiments, the cluster beam directly deposits a protective layer for charged particle beam processing, preferably the protective layer deposition and the charged particle beam processing occur within the same vacuum chamber.

The fig. 1 embodiment shows a simplified diagram of an embodiment of the present invention comprising a chained particle beam system 100 comprising a cluster ion source 102, a gas injection system 104, preferably an electron beam column 106. For example, a gas injection system is described in U.S. Pat. No.5,851,413 to Casella et al. Another gas delivery system, "a gas delivery system for particle beam processing", assigned to the assignee of the present invention, describes a "gas injection system" in U.S. patent No.5,435,850 to lamusmosen, also assigned to the assignee. The cluster source 102 provides a beam 108 of atomic or molecular clusters directed to a region of interest on a workpiece 112, which is located within a vacuum chamber 114 on a stage 116 (not shown), preferably capable of moving in at least two directions.

Figure 2 shows a preferred method according to the invention. In step 210, the workpiece is inserted into the vacuum chamber 114. In step 212, a portion of the workpiece 112 is imaged using the electron beam column 106 to position a marker on the workpiece surface to align the coordinate system of the stage 116. Using the coordinate system of the workpiece 112, the table 116 can be moved to position the region of interest 110 within the region to which the cluster can be directed. In step 214, a jet of precursor gas is directed to the workpiece 112 proximate the region of interest 110. A number of deposition precursors are knownGases including Tetramethylorthosilane (TMOS), Tetraethylorthosilane (TEOS), tetrabutoxysilane Si (OC)₄H₉) Acetylacetonato-dimethyl-gold, organometallic compounds, e.g. tungsten hexacarbonyl (W (CO))₆) And methylcyclopentadienyl trimethylplatinum (C)₉H₁₆Pt)。

In step 216, the cluster beam is directed to the workpiece surface to provide energy to decompose the precursor gas and deposit the protective layer. The present invention may use clusters of different types of atoms or molecules. The term "cluster" includes groups of multiple molecules or atoms. For example, carbon in the form of fullerenes (e.g., C)₆₀，C₇₀，C₈₀Or C₈₄) Gold (Au)₃) Bismuth (Bi)₃) And xenon (Xe)₄₀) And other clusters may be used for deposition or etching. The term "cluster" includes not only the group of multiple fullerenes, but also individual fullerene molecules that are considered to be clusters of carbon atoms. Because each cluster has only one or a few unbalanced charges, the charge-to-mass ratio of the cluster may be significantly less than the charge-to-mass ratio of a single atom or molecule used in the charged particle beam. Although the energy of the entire cluster may be relatively large, e.g., hundreds to thousands of electron volts, the energy of each component is very low.

Typical protective layers are preferably between 0.05 μm and 1 μm, more preferably between 0.1 μm and 0.8 μm, and most preferably around 0.2 μm. The preferred protective layer is sufficiently conductive to eliminate any electrical noise generated by the charged particle beam striking the workpiece. The preferred protective layer is "vacuum friendly," that is, it does not "outgas" or continue to evaporate in the vacuum chamber so as not to interfere with the attractive particle beam or contaminate the workpiece. The preferred protective layer stabilizes the structure on the workpiece. The preferred protective layer does not interact with or change the structure on the workpiece and provides mechanical strength such that the size of the structure changes little or not at all under the influence of the charged particle beam. Deposition is limited to the area near the point of impact of the cluster beam.

Because the mass of the clusters is greater than the mass of the gallium ions in typical prior art methods, damage to the workpiece is limited to being caused by the gallium ion beamWhich impairs the thin surface layer. Depending on the composition, morphology and size of the clusters used and the acceleration voltage, damage to the substrate can be limited to within top 20nm, top 10nm, top 5nm or top 2 nm. For example, to C₆₀The use of 15kV accelerating voltage for Au or Bi clusters typically limits the damage layer to the top 5nm of the workpiece. In contrast, a typical gallium ion beam damages the surface to a depth of about 30 to 50 nm. The preferred accelerating voltage may vary with the type of cluster and the material of the workpiece.

In some embodiments, the protective layer may be composed of a material from a cluster, such as a carbon layer deposited from a fullerene, and in such embodiments, it is not necessary to deposit a precursor gas. I.e. the clusters are deposited directly on the workpiece. In other embodiments, the protective layer is comprised of decomposition products from a precursor gas. In other embodiments, a combination of materials in the cluster beam and decomposition products of the precursor gas are deposited.

In step 218, the region of interest protected by the protective layer is processed by the charged particle beam. For example, a scanning electron microscope may be used to view the target area, or the area may be etched, or other materials may be deposited using an ion beam. If a multi-source system is used as the source of the cluster beam, plasma material that is the source of the clusters can be removed from the plasma chamber and different gases can be filled into the plasma chamber for material removal. Or during which no etch enhancing gas or precursor gas is directed to the region of interest, the process or the material deposition process. An example of a multi-source system is disclosed in U.S. patent application No. 60/830,978 filed on 7/14 2006 for "a multi-source plasma focused ion beam system," which is incorporated herein by reference and assigned to the assignee of the present invention.

In other embodiments, an etch-enhancing gas may be used and the cluster beam provides energy to initiate a chemical reaction to etch the workpiece, thereby reducing damage outside of the etched region. The etch enhancing gas comprises XeF₂，F₂，Cl₂，Br₂,I₂Fluorocarbons, e.g. trifluoroacetamide and trifluoridesAcetic and trichloroacetic acids, water, ammonia and oxygen.

A preferred embodiment of the present invention uses a magnetic enhancement for focused ion beam systems, inductively coupled plasma source, as described in U.S. patent application No. 2005/0183667, incorporated herein by reference. Such ion sources provide a beam with very low chromatic aberration and can be focused to a relatively small spot at relatively high beam currents, making them suitable for precision micromachining and deposition. Such sources can provide cluster beams, as well as single atomic and molecular beams for charged particle beam processing. For example, a protective layer may be deposited using a cluster beam, and then an argon beam may be used with xenon difluoride to micromachine features of a workpiece.

Fig. 3 shows a simplified schematic of a preferred RF excited plasma ion chamber. Ceramic plasma ion chamber 300 is surrounded by coil 302. The coil is energized by an RF source (not shown). Ceramic plasma ion chamber 300 is a cylinder with an open electrode 304 at one end. The orifice electrode has an orifice centered on the cylindrical axis of the ceramic plasma ion chamber 300. The ion beam exits ceramic plasma ion chamber 300 through an aperture of electrode 304 and passes through beam focusing column 306 to produce a deflectable focused ion beam 308.

Ceramic plasma ion chamber 300 receives gas from one or more of a plurality of sources 310, 312, 314 through valve 309. The source may comprise a cluster gas such as described above, an inert gas (He) such as xenon (Xe) or helium, a reactive gas (e.g., oxygen (O)₂) Or the precursor or etch enhancing gas described above. A valve 309 may be provided to sequentially select each of a plurality of different gases from the source. Thus, one ion species may be selected for milling or etching, while a different ion species may be selected for deposition.

The source is convenient in that one material may be provided to the plasma source to generate the cluster beam to provide the protective layer and then a second material may be provided to the plasma source to further process the workpiece. For example, a composition containing C can be introduced₆₀To decompose a precursor gas to deposit a protective layer, and then introducing a gas such as Xe to performAnd (4) sputtering.

Fig. 4 shows a schematic diagram of an alternative embodiment of a cluster source 400. The cluster source 400 may be in its own vacuum chamber, or may be in a vacuum chamber comprising one or more additional charged particle beam columns, such as a focused ion beam column. Such as a liquid metal or plasma source column or an electron beam column. The non-clustered source may be used, for example, to treat the workpiece after the protective layer is applied using the clustered source. The vacuum chamber may include a gas injection system to direct a deposition precursor gas or an etch enhancing gas toward the workpiece.

The cluster source 400 includes a crucible 402 containing a source material 404. The power supply 408 heats the coil 410 to provide energy to vaporize the source material 404. The vaporized atoms or molecules, commonly referred to as constituents, of the source material 404 expand through the nozzle 420, which causes the atoms or molecules to agglomerate into clusters 422. The clusters are preferably loosely bound groups of atoms or molecules. The components preferably do not form a crystalline structure in the clusters, but are amorphous, similar to a liquid state. The components may also be evaporated by laser or electron or ion beam.

The cluster source 400 includes a crucible 402 containing a source material 404. The power supply 408 heats the coil 410 to provide energy to vaporize the source material 404. The vaporized atoms or molecules, commonly referred to as constituents, of the source material 404 expand through the nozzle 420, which causes the atoms or molecules to agglomerate into clusters 422. The clusters are preferably loosely bound groups of atoms or molecules. The components preferably do not form a crystalline structure in the clusters, but are amorphous, similar to a liquid state. The components may also be evaporated by laser or electron or ion beam.

Clusters 422 are linked in an ionizer 430, which ionizer 430 may, for example, comprise an electron source 432 having an electrical potential with a potential that accelerates electrons 434 towards an electrode 436. The electrons 434 collide with the clusters 422, ionizing some of the components. Typically, only a small number of components (e.g., one or two) are ionized, and thus the charge on each cluster is small. The clusters are optionally passed through a mass filter 440, which may use a combination of electrostatic fields, magnetic fields, and apertures, to cause a beam of clusters 442 having a mass within a desired range to exit the mass filter 440 and be directed toward the workpiece. The skilled person will appreciate that the cluster source depicted in fig. 4 is simplified and that many variations and modifications are known and used.

Such cluster sources have been used, for example, to provide coatings for optical components. A typical cluster from the source of fig. 4. Including 2 to 10,000 atoms or molecules. Although the bonds between the components in some clusters (e.g., carbon atoms in fullerenes) are stronger, the components in the clusters may be loosely bonded to each other. An effective cluster source can produce a relatively large number of clusters of the desired size compared to the number of unconnected components or clusters of poor size produced. The clusters are charged and are usually directed to the target by electrostatic forces. Since the components may be loosely bound in the clusters, the energy of the clusters causes them to disintegrate upon impact and spread the components into a relatively thin, uniform layer on the surface.

Cluster ion source (including use of C)₆₀Those ion sources) have been used in secondary mass spectrometry to eject material from a workpiece surface. The low energy of each component ensures that little momentum is transferred to the individual atoms and molecules in the workpiece, resulting in very little mixing of the workpiece materials.

The term charged particle beam "processing" as used herein includes imaging as well as sputtering, etching and deposition.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. According to the present invention, substantially the same results as in the corresponding embodiments described herein may alternatively be achieved. Accordingly, the appended claims are intended to include within their scope such processes, compositions of matter, means, methods, or steps.