TW201303515A - Method and system for design of a surface to be manufactured using charged particle beam lithography - Google Patents

Abstract

A method and system for fracturing or mask data preparation are disclosed which can reduce the critical dimension variation of patterns formed on a resist-coated surface using particle beam lithography by providing a higher peak dosage near the perimeter of the patterns than in the interiors of the patterns.

Description

Design method and system for surfaces to be fabricated using charged particle beam lithography Related application

This application claims to be filed on February 28, 2011, and the title of the invention is "Method and System For Design Of A Surface To Be Manufactured Using." U.S. Patent Application Serial No. 13/037,263, the disclosure of which is incorporated herein by reference. This application is also filed on February 28, 2011, and the title of the invention is "Method and System For Design Of Enhanced Accuracy Patterns For Charged." U.S. Patent Application Serial No. 13/037,268, the entire disclosure of which is incorporated herein by reference in its entirety in its entirety in its entirety in U.S. Patent Application Serial No. 13/037,270, the disclosure of which is incorporated herein by reference.

Technical field

The present invention is directed to lithography, and in particular to the design and manufacture of surfaces using charged particle beam lithography, which may be reticles, wafers or any other surface.

Photolithography can be used to fabricate semiconductor components in the production or manufacture of semiconductor components such as integrated circuits. Photolithography is a printing process in which a lithographic mask or reticle made of a reticle is used to transfer a pattern onto a substrate such as a semiconductor or germanium wafer to produce an integrated circuit (I.C.). Other substrates may include flat panel displays or even other pleated reticle. Furthermore, extreme ultraviolet (EUV) or X-ray lithography is considered to be the type of photolithography. The reticle or multi-fold reticle may contain a circuit pattern corresponding to individual layers of the integrated circuit, and the pattern may be imaged on a layer of radiation sensitive material of the substrate that has been coated with a known photoresist or resist. On a specific area. Once the patterned layer is transferred, the layer can be subjected to a variety of other processes such as etching, ion implantation (doping), metallization, oxidation, and polishing. These processes are applied to complete individual layers in the substrate. If several layers are required, each new layer will repeat the entire process or its changes. Finally, a combination of most components or integrated circuits will be presented on the substrate. These integrated circuits can then be separated from one another by cutting or sawing and can then be mounted into individual packages. In a more general example, the pattern on the substrate can be used to define a finished product, such as a display pixel, hologram, or magnetic recording head.

In the production or manufacture of semiconductor components such as integrated circuits, maskless direct write can also be used to fabricate semiconductor components. The maskless writing is a printing process in which charged particle beam lithography is used to transfer a pattern to a substrate such as a semiconductor or germanium wafer to produce an integrated circuit. Other substrates may include flat panel displays, imprint reticle for nanoimprinting, or even pleated reticle. The desired pattern of a layer is written directly onto the surface, which in this example is also a substrate. Once the pattern layer is transferred, This layer can be subjected to a variety of other processes such as etching, ion implantation (doping), metallization, oxidation, and polishing. These processes are applied to individual layers in the final processed substrate. If several layers are required, each new layer will repeat the entire process or its changes. Some layers can be written using photolithography, while other layers can be written using a maskless direct write to make the same substrate. In addition, a partial pattern of a particular layer can be written using photolithography and other patterns are written straight using a maskless. Finally, a combination of most components or integrated circuits will appear on the substrate. These integrated circuits are then separated from each other by cutting or sawing and then mounted into individual packages. In a more general example, the pattern on the surface can be used to define, for example, a display pixel, a hologram, or a magnetic recording head.

Two common forms of charged particle beam lithography are variable shape electron beam (VSB) and symbol projection (CP). These are all sub-categories of shaped electron beam charged particle beam lithography in which a precision electron beam is shaped and manipulated to expose a photoresist-coated surface, such as a wafer surface or a pleated reticle surface. In VSB, these forms are simple shapes, generally limited to a particular minimum and maximum size rectangle, and have sides parallel to the axis of the Cartesian coordinate plane (ie, having a Manhattan orientation), and a specific minimum And a 45-degree equilateral triangle of the largest size (ie, a triangle with three internal angles of 45 degrees, 45 degrees, and 90 degrees). At a predetermined location, the electronic dose is shot into a photoresist having such a simple shape. The total write time for this system form increases with the number of shots. In symbol projection (CP), there is a template in the system with various apertures or symbols, which can be complex shapes, such as lines, lines of any angle, circles, and near circles. , ring, nearly annular, elliptical, nearly elliptical, partially circular, partially nearly circular, Partially annular, partially proximally annular, partially nearly elliptical, or any curved shape, and may be a group of connected complex shapes or a group of connected complex shapes that are mostly disjointed. The electron beam can be fired through one of the symbols on the stencil to efficiently produce a more complex pattern on the reticle. In theory, this system can be faster than a VSB system because it can shoot more complex shapes every time it takes time. Therefore, it takes 4 shots to shoot with the E-type pattern of the VSB system, but with the symbol projection system, the same E-pattern can be shot with one shot. It should be noted that the VSB system can be regarded as a special (simple) case of a symbol projection, where these symbols are simply symbols, generally rectangular or a 45-45-90 degree triangle. It is also possible to partially expose a symbol. This can be done, for example, by blocking a partial particle beam. For example, the E-type pattern described above may be partially exposed to an F-type pattern or an I-type pattern in which different beam portions are truncated by an aperture. This is the same as how you can use VSB to shoot rectangles of different sizes. In this disclosure, local projection is used to mean both symbol projection and VSB projection.

As indicated, in photolithography, the lithographic mask or reticle comprises a geometric pattern corresponding to the circuit elements to be integrated onto the substrate. The pattern used to make the reticle can be created using computer aided design (CAD) software or programming. In designing a pattern, the CAD program can follow a predetermined set of design rules to produce a reticle. These rules can be set by processing, design and end-use restrictions. An example of end-use limitations is to define the geometry of the transistor in a manner that does not operate adequately at the required supply voltage. In particular, design rules can define spatial tolerances between circuit devices or interconnects. This design rule is for example used to ensure that the circuit arrangement or line is undesired. The way to interact with the other. For example, design rules are used so that the wires do not get too close to each other in a way that can cause a short circuit. Among other things, this design rule limits the minimum size that can be reliably manufactured. When referring to these minimum dimensions, the concept of critical dimensions is often introduced. These are for example defined as the minimum width of a line or the minimum space between two lines, which require fine control.

One of the goals in the fabrication of integrated circuits by photolithography is to replicate the original circuit design on the substrate by using a reticle. Integral circuit manufacturers are always trying to use the true state of semiconductor wafers as efficiently as possible. Engineers keep the circuit down to allow the integrated circuit to contain more circuit components and use less power. As the critical dimension of the integrated circuit is reduced and its circuit density is increased, the critical dimension of the circuit pattern or solid design approximates the resolution limit of the optical exposure tool used in photolithography. Since the critical dimension of the circuit pattern becomes smaller and approaches the resolution value of the exposure tool, precise transcription of the actual circuit pattern that is physically designed to develop on the photoresist layer becomes difficult. In order to further use photolithography to transfer patterns having features that are smaller than the wavelength of light used for photolithography, a process known as optical proximity correction (OPC) has been developed. The OPC changes the physical design to compensate for distortion caused by, for example, light diffraction and effects of light interactions with features and immediate features. OPC includes all resolution enhancement techniques performed using a reticle.

The OPC can add sub-analytical lithography features to mask the pattern to reduce the original physical design pattern, that is, the difference between the design and the circuit pattern that is ultimately transferred on the substrate. The analytical lithography features interact with the original patterns in the physical design and interact with each other, and compensate for the close effect to improve the final turn. Move the circuit pattern. One feature used to improve the transfer of patterns is the Secondary Analytical Auxiliary Feature (SRAF). Another feature added to improve pattern transfer is called "serif". The serif is a small feature that can be placed in a corner of the pattern to sharpen the corner of the final image being transferred. The usual situation is that the surface fabrication method of SRAF requires less precision than the pattern to be printed on the substrate, which is commonly referred to as the main feature. The serif is part of the main feature. Because the limitations of photolithography extend into the sub-wavelength regime, the OPC features must be made more complex, so as to compensate for more subtle interactions and effects. As the imaging system is pushed closer to its limits, the ability to fabricate a pleated reticle with sufficiently fine OPC features becomes critical. While it is advantageous to add serifs or other OPC features to the reticle pattern, it also substantially increases the total feature count in the reticle pattern. For example, using a conventional technique to add a serif to each corner of a square will add an additional 8 rectangles to the reticle or reticle. Adding OPC features is a laborious task that requires extremely high computational time and results in a more expensive reticle. Not only is the OPC feature complex, but because the optical proximity effect is relatively long-range with the minimum line spacing size, the correct OPC pattern at a given location is significantly dependent on the proximity of other geometries. Thus, for example, depending on the neighbors on the reticle, the ends of the wire will have serifs of different sizes. Even if the purpose may be to make exactly the same shape on the wafer. These minor but critical changes are important and have prevented the avoidance of other doubling mask patterns. Traditionally, the OPC decoration to be written on the reticle has been discussed from the perspective of main features, which are features reflected before OPC decoration, and OPC features, among which OPC Features may include serifs, right angle jogs, and SRAF. To quantify the significance of minor changes, typical slight changes in OPC decorations from adjacent regions to adjacent regions can range from 5% to 80% of the main feature size. It should be noted that for the sake of clarity, reference is made to changes in the OPC design. Manufacturing variations, such as line edge roughness and corner rounding, also occur in actual surface patterns. When such OPC variations produce substantially the same pattern on the wafer, it means that the geometry on the wafer is specified to be the same within the specified error, depending on the functional details that the geometry is designed to perform, such as electricity. Crystal or wire. However, typical specifications range from 2% to 50% of the main feature range. There are countless manufacturing factors that also cause variations, but the overall OPC component is generally within the scope of the listing. For example, the OPC shape of the secondary resolution assist feature is governed, for example, by a variety of different design rules, such as rules based on the minimum feature size that can be transferred to the wafer using photolithography. Other design rules may come from the reticle process or if the symbol projection charged particle beam writing system is used to form a pattern on the reticle, it may come from a stencil process. It should also be noted that the accuracy requirements of the SRAF features on the reticle may be lower than the accuracy requirements of the main features on the mask.

There are many techniques for forming a pattern on a reticle, including the use of photolithography or charged particle beam lithography. The most commonly used system is a variable shape electron beam (VSB), wherein as described above, an electron dose having a simple shape such as a Manhattan triangle and a 45-degree equilateral triangle makes the photoresist coated reticle surface exposure. In conventional mask writing, the dose or shot of electrons has traditionally been designed to avoid overlap as much as possible, so that the calculation of how the photoresist on the reticle is recorded on the pattern can be greatly simplified. similar Ground, a set of shots is designed so as to completely cover the pattern to be formed on the reticle.

The doubling mask writing for the most advanced technology nodes generally involves multiple charged particle beam writing, a so-called multiple exposure process, whereby the reticle is written and overwritten with a predetermined shape. In general, using two to four tracks to write the reticle to average the precision error of the charged particle writer allows for a more accurate reticle. In general, the list of shots including doses is also the same for each lane. In one of the multiple exposures, the shot list can change between multiple exposures, but the joint of shots in either exposure covers the same area. Multiple writes can reduce overheating of the photoresist coated surface. Multiple writes also average the random error of the charged particle beam writer. Multiple writes using different shot lists for different track exposures can also reduce the effects of specific systemic errors in the write process.

There are numerous undesired short-range effects and long-range effects associated with exposure in charged particles. For example, the long-range effects of backscattering and fogging are a function of the sum of the doses in the pattern area referred to as the regional dose, or a function of the total dose of all shots written to the surface. Therefore, it is desirable to be able to reduce the total dose received by the surface of the substrate or reticle while still forming the desired pattern on the photoresist within predetermined tolerances. Furthermore, it is advantageous to simultaneously reduce the time required to expose the pattern on the surface so that the cost of manufacturing a surface such as a reticle or wafer can be reduced.

Summary of invention

The invention discloses a method and system for shredding or masking data preparation A set of charged particle beam shots produces a peak dose that is higher than the interior of the desired pattern near the periphery of the desired pattern. The techniques disclosed herein advantageously reduce critical dimension variations of patterns in semiconductor fabrication while preventing unnecessary increases in total dose. In a specific embodiment, a gap may be left between the shot profiles, wherein the gap is sufficiently small that no gaps will be formed on the surface. In other embodiments, overlapping shots can be used. In yet another embodiment, the use of a tow shot is included. This method can be used with variable beam (VSB) shots, symbol projection (CP) shots, or a combination of VSB and CP shots.

Simple description of the schema

1 is a diagram illustrating an embodiment of a symbolic charged particle beam system; FIG. 2A illustrates an embodiment of a single charged particle beam shot and a cross-sectional dose diagram of the shot; FIG. 2B illustrates a pair An embodiment of an adjacent shot and a cross-sectional dose map of the shot pair; FIG. 2C illustrates an embodiment of a pattern formed on the photoresist coated surface from the pair of shots of FIG. 2B; FIG. 3A An embodiment of a polygonal pattern is illustrated; FIG. 3B is an embodiment illustrating the conventional fragmentation of the polygonal pattern of FIG. 3A; and FIG. 3C is a diagram illustrating an alternative fragmentation of the polygonal pattern of FIG. 3A. Embodiment; Figure 4A is a diagram illustrating a shot from a rectangular shot Example; Figure 4B is an illustration of an embodiment of a longitudinal firing curve shot using Figure 4A of a normal firing dose; Figure 4C is an illustration of an embodiment of a longitudinal firing curve similar to Figure 4B including a long range effect; 4D is an illustration of an embodiment of a longitudinal firing curve shot using a 4A map shot above a normal firing dose; FIG. 4E is an illustration of an embodiment of a longitudinal firing curve similar to 4C chart including a long range effect; The 4F diagram illustrates an embodiment similar to the longitudinal firing curve of Figure 4E but with a higher background dose level; Figure 5A illustrates an embodiment of a circular pattern to be formed on a surface; An embodiment illustrating the outline of nine shots that may form the pattern of Figure 5A; Figure 6A illustrates an embodiment of a pattern comprising two squares prior to OPC; Figure 6B illustrates the An embodiment of a curved pattern made by the OPC process of the pattern of FIG. 6A; FIG. 6C is an embodiment illustrating how the pattern of FIG. 6B forms a curved pattern by dragging a circular CP shot and a VSB shot. FIG 6D illustrates a first pattern of the first line of FIG. 6B how the circular CP shot by boxes and VSB shot another embodiment of the curved pattern is formed; FIG. 7 illustrates a system for producing photolithographic of how prepared using For example, a conceptual flow diagram of a surface of a substrate of an integrated circuit on a germanium wafer, such as a reticle, and FIG. 8 illustrates how to prepare a substrate for fabricating an integrated circuit such as a germanium wafer. Conceptual flow chart of the surface.

Detailed description of specific embodiments

The present disclosure describes a method for shredding a pattern into a shot for a charged particle beam writer, wherein a peak dose above the pattern is provided near the perimeter of the pattern. This method reduces the critical dimension (CD) variation of subsequent patterns on the surface.

Referring now to the drawings in which like reference numerals refer to the like, FIG. 1 illustrates a particular embodiment of a conventional lithography system 100, such as a charged particle beam writer system, in this example an application symbol An electron beam writer system that projects to produce surface 130. The electron beam writer system 100 has an electron beam source 112 that projects an electron beam 114 toward the orifice plate 116. A hole 118 is formed in the plate 116 that allows the electron beam 114 to pass. Once the electron beam 114 passes through the aperture 118, it is directed or deflected by an lens system (not shown) into an electron beam 120 toward another rectangular aperture plate or template mask 122. A plurality of apertures or apertures 124 are formed in the template 122 that define various different forms of symbols 126, which may be complex symbols. Each of the symbols 126 formed in the template 122 can be used to form a pattern 148 on a surface 130 of the substrate 132, such as a germanium wafer, a pleated reticle, or other substrate. In partial exposure, partial exposure, partial projection, local symbol projection, or variable symbol projection, the electron beam 120 can be positioned to only impact or illuminate one of the symbols 126 Thus, a pattern 148 is formed which is a subset of the symbols 126. For each symbol 126, it is smaller than the size of the electron beam 120 defined by the aperture 118, and the aperture-free masking region 136 is designed to be adjacent to the symbol 126 so as to prevent the electron beam 120 from being illuminated. The desired template 122 is on the symbol. Electron beam 134 emerges from one of symbols 126 and passes through an electromagnetic or static reduction lens 138 that reduces the pattern size from symbol 126. In the commonly available charged particle beam writer system, the reduction factor is between 10 and 60. The reduced electron beam 140 emerges from the reduction lens 138 and is directed by a series of deflectors 142 to the surface 130 as a pattern 148, which is depicted as having the shape of the letter "H" of the corresponding symbol 126A. Because the lens 138 is reduced, the pattern 148 has a reduced size compared to the symbol 126A. Pattern 148 is depicted by firing using one of electron beam systems 100. This reduces the overall write time of the completed pattern 148 as compared to using a deformable beam (VSB) projection system or method. Although it is shown that a hole 118 is formed in the plate 116, it is possible to form more than one hole in the plate 116. Although two plates 116 and 122 are shown in this embodiment, there may be only one or more than two plates, each plate containing one or more holes.

In a conventional charged particle beam writer system, the reduction lens 138 is calibrated to provide a fixed reduction factor. The reduced lens 138 and/or deflector 142 also focuses the particle beam on the plane of the surface 130. The size of the surface 130 can also be significantly greater than the beam deflection capability of the deflector plate 142. Therefore, the graphic is generally written on the surface in the form of a series of stripes. Each strip has a majority of subfields, one of which is within the beam deflection capability of deflection plate 142. The electron beam writer system 100 includes a positioning mechanism 150 to permit positioning of the substrate 132 for each stripe and subfield. A change in the traditional charged particle beam writer system The substrate 132 remains stationary while a subfield is exposed, after which the positioning mechanism 150 moves the substrate 132 to the next subfield position. In another variation of the conventional charged particle beam writer system, the substrate 132 is continuously moved during the writing process. In this variation involving continuous movement, when the substrate 132 is moved, in addition to the deflection plate 142, another set of deflection plates (not shown) move the beam at the same speed and direction.

The smallest size pattern that can be projected onto surface 130 with reasonable accuracy is limited by the different short range physical effects associated with electron beam writer system 100 and surface 130, which typically include a photoresist coating on substrate 132. These effects include front scatter, Coulomb effect, and photoresist diffusion. Beam blur is a term used to include all such short-range effects. The most modern electron beam writer system achieves effective beam blur from 20 nm to 30 nm. The front scatter can constitute a quarter to a half of the total beam blur. Modern electron beam writer systems contain a myriad of mechanisms to minimize the obscuration of each beam. Partial electron beam writer systems can tolerate beam blurring during writing, from the minimum available to the electron beam writing system to one or more larger values.

The firing dose of a charged particle beam writer, such as an electron beam writer system, is a function of the intensity of the beam source 112 and the exposure time of each shot. In general, the beam intensity remains fixed and the exposure time is varied to obtain a variable firing dose. The exposure time can be varied to compensate for a variety of different long range effects, such as backscattering and fogging during so-called proximity effect correction (PEC). An electron beam writer system generally allows for setting a total dose, referred to as a base dose, which affects all shots of an exposure operation. Partial electron beam writer The system performs a dose compensation calculation within the electron beam writer system itself and does not allow the dose for each shot to be individually specified as part of the input shot list, so the input shot has an unspecified shot dose. Prior to the proximity effect correction, in this electron beam writer system, all shots had a base dose. Other electron beam writer systems do allow for dose specification on a one-by-one basis. In an electron beam writer system that allows one shot dose to be specified, the number of dose levels available is 64 to 4096 or more, if there are relatively small dose levels, such as 3 to 8 degrees. Some embodiments of the present invention are directed to use with a charged particle beam writing system that does not allow for dose specification on a firing-by-shot basis, or that allows for the designation of one of a relatively small dosage level.

2A-B are diagrams illustrating how energy is recorded on a photoresist coated surface from one or more charged particle beam shots. In Figure 2A, the rectangular pattern 202 illustrates a shot profile that is fired from one of the other non-adjacent shots that will produce a pattern on the photoresist coated surface. In dose map 210, dose curve 212 illustrates the cross-sectional dose along line 204 by firing profile 202. Line 214 represents the photoresist threshold above which the photoresist will record a pattern. As can be seen from the dose map 210, the dose curve 212 is above the photoresist threshold between the X-coordinates "a" and "b". The coordinate "a" corresponds to the dashed line 216, which represents the leftmost extent of the shot profile 202. Similarly, the coordinate "b" corresponds to the dashed line 218, which represents the rightmost extent of the shot profile 202. In the example of Figure 2A, the firing dose for firing is a normal dose, as indicated on the dose map 210. In the traditional mask writing methodology, the normal dose is set so that there is no long-range effect, relatively A large rectangular shot will record a pattern of the desired size on the photoresist coated surface. Thus the normal dose will depend on the value of the photoresist threshold 214.

Figure 2B is a graphical representation of the firing profile of a two-particle beam shot, and the corresponding dose curve. The shot profile 222 and the shot profile 224 are derived from two adjacent particle beam shots. In dose map 220, dose curve 230 illustrates the dose along line 226 by firing profiles 222 and 224. As shown by the dose curve 230, the dose recorded by the photoresist along line 226 is, for example, a combination of the sum of the two-particle beam shots represented by the shot profile 222 and the shot profile 224. As can be seen, the dose curve 230 is above the threshold 214 from the X-coordinate "a" to the X-coordinate "d". This means that the photoresist will record the two shots as a single shape, extending from the coordinate "a" to the coordinate "d". Figure 2C illustrates a pattern 252 that is a pattern that can be formed from the two shots of the embodiment of Figure 2B. The variable width of pattern 252 is the result of the gap between shot profile 222 and shot profile 224, and illustrates that the gap between shots 222 and 226 causes the dose to drop below a threshold of the corner of the shot profile closest to the gap.

When using conventional non-overlapping shots, it uses a single exposure operation, traditionally all shots are assigned a normal dose before the PEC dose adjustment. Therefore, a charged particle beam writer that does not support a shot-by-shot dose can be used by setting a base dose to a normal dose. If the charged particle beam writer uses most exposure operations, the base dose is conventionally set according to the equation: basic dose = normal dose / number of exposure operations.

3A-C are diagrams illustrating two methods of known shredding polygon patterns. Figure 3A illustrates a polygonal pattern 302 to be formed on a surface. Figure 3B illustrates a conventional method of forming this pattern using non-overlapping or disjoint shots. The shot profile 310, the shot profile 312, and the shot profile 314 do not intersect each other. In addition, the three shots associated with these shot profiles use the desired normal dose prior to proximity correction. An advantage of using the conventional method as shown in Fig. 3B is that the reaction of the photoresist can be easily expected. Further, the shot of FIG. 3B can be exposed by setting the basic dose of the charged particle beam writer to a normal dose, using a charged particle beam system that does not allow dose specification based on the shot-by-shot dose. Figure 3C is a diagram illustrating the method and system for designing a reticle for use with variable shape electron beam lithography, which was filed on May 27, 2009. An alternative method of forming a pattern 302 on a photoresist coated surface by overlapping shots of U.S. Patent Application Serial No. 12/473,265, the disclosure of which is incorporated herein by reference. In Figure 3C, the limits of the shot contours that cannot be overlapped have been eliminated, and the shots 320 and shots 322 do overlap, and none of the shots are the set of shot profiles of the other. In the embodiment of Figure 3C, the firing profile is allowed to overlap such that the pattern 302 is formed with only two shots as compared to the three shots of Figure 3B. However, in Figure 3C, the resistance of the photoresist to overlapping shots is not as predictable as in Figure 3B. In particular, because of the large dose received by the overlap region 332, as indicated by the horizontal hatching, the interior corners 324, 326, 328, and 330 may be recorded as excessively rounded. Charged particle beam simulation can be used to determine the pattern recorded by the photoresist. In a specific embodiment, charged particle beam simulation can be used to calculate in a two-dimensional (X and Y) grid. The dose at each grid location produces a grid of calculated doses for the so-called dose map. The results of the charged particle beam simulation can represent the use of an abnormal dose for shot 320 and shot 322. Moreover, in Figure 3C, the overlap of the shots in area 332 causes the area dose to increase beyond the area dose it will have without shot overlap. Although the overlap of the two individual shots will not significantly increase the regional dose, this technique will increase the regional dose and will increase the total dose if used throughout the design.

At the time of exposure, for example, a pattern of overlapping on the surface by charged particle beam lithography is used, and the size of each pattern example, as measured on the final manufactured surface, will be slightly different due to manufacturing variations. The amount of dimensional variation is the standard for major manufacturing optimization. In today's reticle masking technology, the desired root mean square (RMS) variation is no more than 1 nm (1 sigma). More variations in the performance of the size variation conversion circuit result in the need for higher design margins, making the design of faster, lower power integrated circuits more difficult. This change is called a critical dimension (CD) change. Low CD variations are desirable and indicate that manufacturing variations will result in relatively small dimensional variations on the final fabricated surface. On a smaller scale, the effect of high CD variations can be observed with line edge roughness (LER). The LER is caused by a slightly different portion of the edge of each line, resulting in a partial ripple of the line to have a straight edge. The CD change is inversely related to the slope of the dose curve at the photoresist threshold called the edge slope. Therefore, the edge slope or dose limit is the key optimization factor for particle beam writing on the surface.

4A is an illustration of an embodiment of a contour of a rectangular shot 402. Figure 4B is a diagram illustrating the normal firing dose, without, for example, if the shot 402 is the only shot within the range of backscattering effects, for example, 10 microns. Backscattering, one embodiment of a dose map 410 of doses along line 404 by firing profile 402. Other long-range effects also assume that they do not contribute to the background exposure of Figure 4B, resulting in zero background exposure. The total dose delivered to the photoresist is illustrated on the y-axis and is 100% of the normal dose. Because of the zero background exposure, the total dose and firing dose are the same. The dose map 410 also illustrates the photoresist threshold 414. The change in CD from the shape represented by the dose map 410 in the x-direction, and the dose curve 412 intersecting the photoresist threshold are inversely correlated at the slopes of the x-coordinates "a" and "b".

The zero background exposure conditions of Figure 4B do not reflect the actual design. The actual design will typically have many other shots within the backscatter distance of shot 402. Figure 4C illustrates an embodiment of a dose map 420 of a normal dose shot with a non-zero background exposure 428. In this embodiment, a background exposure of 20% of the normal dose is displayed. In dose map 420, dose curve 422 is a cross-sectional dose illustrating a shot similar to shot 402. Due to the background exposure caused by backscattering, as shown by the lower edge slope of curve 422 and photoresist threshold 424 at the intersection of points "a" and "b", the CD change of curve 422 is worse than the CD change of curve 412.

A method of increasing the slope of the dose curve at the photoresist threshold is to increase the firing dose. Figure 4D illustrates an embodiment of a dose map 430 having a dose curve 432 with a total dose of 150% of the normal dose without background exposure. Without background exposure, the firing dose is equal to the total dose. The threshold 434 in the 4D plot is not changed by the threshold 414 in FIG. 4B. Increasing the shot dose increases the size of the pattern recorded by the photoresist. Therefore, in order to maintain the size of the photoresist pattern, such as an illustration of the intersection of the dose curve 432 and the threshold 434, for the dose map 430 The shot size is slightly smaller than shot 402. As shown, the slope at which the dose curve 432 intersects the threshold 434 is higher than the slope at which the dose curve 412 intersects the threshold 414, indicating that the higher dose shot of the 4D map has a lower normal dose than the 4B map, modified CD changes.

However, similar to dose map 410, the zero background exposure conditions of dose map 430 do not reflect the actual design. Figure 4E is an illustration of an embodiment of a dose map 440 having a firing dose adjusted to achieve a background exposure of 20% with a total dose on the photoresist of 150% of the normal dose, such as a dose of only one shot increased to 150% And other shots will remain 100% of the normal dose will occur. The threshold 444 is the same as the 4B-4D map. Background exposure is illustrated on line 448. As shown, the slope of the dose curve 442 at the x-coordinates "a" and "b" is smaller than the slope of the dose curve 432 at the x-coordinates "a" and "b" because of backscatter. Comparing Figures 420 and 440 to see the effect of firing dose, the slope of dose curve 442 at x-coordinates "a" and "b" is higher than the slope of dose curve 422 at the same x-coordinate, indicating that if the doses of other shots remain the same, An improved edge slope can be obtained by increasing the dose.

Figure 4F is an illustration of an embodiment of a dose map 450 illustrating the case where the dose of all shots has increased to a normal dose of 150%. The two background dose levels are shown on the dose map 450: 30% background dose 459, for example, if all shots are used with 150% of the normal dose, and a background dose of 458 is shown for comparison, because 20% is the dose map 440 Background dose. Dose curve 452 is based on a 30% background dose 459. As can be seen, the edge slope of the dose curve 452 at x-coordinates "a" and "b" is less than the edge slope of the dose curve 442 at the same point.

In summary, the 4A-F diagram illustrates the use of higher than normal doses to selectively reduce CD variations in the shape of the isolation. However, increasing the dose has two undesirable effects. First, the increase in dose is achieved by extending the exposure time with a modern charged particle beam writer. Therefore, an increase in dose increases the writing time, which increases the cost. Second, as illustrated in Figure 4E-F, if many shots within the backscattering range of each other use increased doses, the increase in backscattering reduces the edge slope of all shots, thereby attenuating CDs for all shots of a given specified dose. Variety. The method of avoiding this problem for any given shot is to increase the dose and launch in a smaller size. However, doing so even increases backscatter. This cycle causes all shots to be at higher doses, making the number of writes worse. Therefore, it is preferred to only increase the dose used to define the shot of the edge.

The edge slope or dose limit is only a problem at the edge of the pattern. For example, if the normal dose is a 2x photoresist threshold to provide a good edge slope, the dose in the inner region of the pattern can be lower than the normal dose, as long as the internal dose is kept above the partial limit of the manufacturing variation. The photoresist threshold is sufficient. In the disclosure of the present invention, two methods of reducing the dose of the inner region of the pattern are disclosed.

̇ If the specified firing dose is available, the dose used is lower than the normal dose.

插入 Insert a gap between the shots inside the pattern. Although the shot profile may show a gap, if the dose in the gap region is above the photoresist threshold everywhere, there is no limit for manufacturing variations, and there will be no gap recorded by the photoresist. One or both of these two techniques will reduce the regional dose and therefore reduce The background dose caused by the scattering. The slope at the edge of the pattern edge will thus increase, thereby modifying the CD variation.

Optimization techniques can be used to determine the lowest dose that can be achieved inside the pattern. In some embodiments, such optimization techniques will include calculating a photoresist response to the set of shots, such as using particle beam simulation, such that it can be determined that the set of shots may form a desired pattern within a predetermined tolerance. It should be noted that when firing is generated for a charged particle beam that only supports unspecified dose shots, the gap can be used for the inner region of the pattern to reduce the regional dose and total dose. By simulating, in particular, "corner cases" that create tolerances, designs with lower doses or gaps can be predetermined, with reduced write times and modified edge slopes to safely shoot the desired shape.

Figure 5A illustrates an embodiment of a circular pattern 502 to be formed on a surface. Figure 5B illustrates an embodiment of how pattern 502 can be formed using a set of nine VSB shots having a specified firing dose. Figure 5B illustrates the individual firing profiles of the nine shots. In Figure 5B, because overlapping shots 512, 514, 516, 518, 520, 522, 524, and 526 each define the perimeter of the pattern on the surface, such shots may be assigned a relatively high dose group, or may all be specified Normal dose to maintain a good edge slope. However, because shot 530 does not define an edge of the pattern, shot 530 can have a specified dose that is less than shots 512, 514, 516, 518, 520, 522, 524, and 526, such as a 0.7x normal dose. The firing size is carefully chosen such that no part of the interior of shape 502 falls below the photoresist threshold, perhaps with a certain manufacturing variation. Shooting 530 can also be made to size such that between the contour of shot 530 and the contour of each adjacent shot In the presence of a gap, as illustrated in Figure 5B. When a gap exists, the combination of the shot profiles in the set of shots does not cover the desired pattern. Particle beam simulation can be used to determine the optimal size of the gap so that the dose can be reduced without causing a gap recorded by the photoresist. When applied to a large number of such shots 530 within the backscattering range of such shots as compared to exposure shots 530 having normal doses, using lower than normal doses at shot 530 will reduce backscattering and fogging, Helps to modify the edge slope.

The resolution described in Figure 5B above, even with a charged particle beam system that does not allow for the dose of individual shots, can be implemented. In a specific embodiment of the present invention, a small amount of a dose, such as a 1.0x normal dose and a 0.7x normal dose, may be selected, and the individual shots of the two doses may be separated and exposed in a two-part exposure process. The base dose for one exposure course is 1.0x normal dose and the base dose for another exposure course is 0.7x base dose. In the embodiment of Figure 5B, shots 512, 514, 516, 518, 520, 522, 524, and 526 may specify a first exposure history that uses a base dose of 1.0 x normal dose prior to PEC correction. Shot 530 can specify a second exposure history that uses a base dose of 0.7x normal dose prior to PEC correction.

Even with a charged particle beam writer that does not support the dose of individual shots, overlapping shots can be used to produce a photoresist dose greater than 100% of the normal dose. In FIG. 5B, for example, shots 514 and 512, shots 526 and 524, shots 520 and 522, and shots 518 and 516 may be contoured to create an area that is higher than the normal dose at the periphery. The higher energy projected from such areas can "fill" between the shot silhouette 530 and the surrounding shots. The gap makes it possible to reduce the size of the shot 530.

Figure 6A illustrates a pattern comprising two squares 604 and 606, such as a contact or via layer that may occur in an integrated circuit design. Figure 6B illustrates a curved pattern 610 resulting from an advanced OPC process of the pattern of Figure 6A. Pattern 610 is an ideal pattern to be formed on a reticle, which will be used in a photolithography process to produce patterns similar to 604 and 606 on the substrate. Pattern 610 is comprised of two main shapes: shape 612 and shape 614, and seven SRAF shapes: shape 620, shape 622, shape 624, shape 626, shape 628, shape 630, and shape 632. Figure 6C is a diagram illustrating an embodiment 640 of how the drag shot can be applied to form a pattern 610 of the majority of Figure 6B. The towed shooting system is disclosed in the US Patent Application No. 5, 2010, and the invention is entitled "Method and System For Manufacturing a Surface Using Charged Particle Beam Lithography". This document is incorporated herein by reference in its entirety. For example, most of the dashed circles in pattern 650 represent a single drag shot of a circular CP symbol. Shooting group 640 includes drag shots 642, 644, 650, 652, 654, 656, 658, 660, and 662 plus VSB shots 664 and 666. In Figure 6C, VSB shots 664 and 666 have an embedded "X" pattern to aid in illustration. The VSB firing profiles 664 and 666 overlap the contours of the tow shots, which define the perimeter of the patterns 642 and 644. In one embodiment of the present disclosure, shot 664 and shot 666 are designated to be lower than the normal dose when using a charged particle beam writer with individual shot dose specifications. Figure 6D is a graphical illustration of In another embodiment of the present disclosure, how many tow shots and two VSB shots can be used to form the pattern of Figure 6B. In the tow shot of FIG. 6D, the shooting group 670 is the same as the shooting group 640. However, the VSB shots 694 and 696 in Figure 6D are smaller than the VSB shots 664 and 666 in Figure 6C. As can be seen in Figure 6D, there is a gap between the VSB shot profile and the drag shot profile. When, for example, particle beam simulation calculations are used, the reaction of the photoresist can indicate that the dose system in all regions of the gap is above the photoresist threshold, wherein the smaller VSB shots of the fire group 670 reduce the area in the contact or via pair For regional doses, the smaller VSB shots of the fire group 670 are better than the VSB shots of the fire group 640.

In a particular embodiment of the invention, the gap between the normal dose or near normal dose shot can be filled or partially filled with a low dose shot, such as a shot having a normal dose of less than 50%.

The dose received by the surface can be calculated and stored as a two-dimensional (X and Y) dose map of characters. A two-dimensional dose map or character is a two-dimensional grid of calculated dose values adjacent to the shot containing the character. This dose map or character can be stored in the character library. The character library is used for input when shredding a pattern in a design. For example, referring again to Figures 5A and 5B, dose maps of shots 512, 514, 516, 518, 520, 522, 524, and combinations of 526 and 530 can be calculated and stored in a character library. If during the shredding, one of the input patterns is a circle of the same size as the circular pattern 502, the characters of the pattern 502 and the nine shots containing the characters can be retrieved from the library to avoid determining the appropriate shot group to form a circular input. The calculated labor of the pattern. Characters can also contain CP shots and can contain dragged CP or VSB shots. A series of characters can also be combined to produce a parameterized word symbol. The parameters can be discontinuous or continuous. For example, shots and dose maps for forming a circular pattern, such as circular pattern 502, may be suitable for most pattern sizes, and most of the resulting characters may be combined to form discrete parametric characters. In another embodiment, the pattern width can be parameterized as a function of the drag firing speed.

Figure 7 is a conceptual flow diagram illustrating how to prepare a reticle for fabricating, for example, one of the integrated circuits on a wafer. In a first step 752, the physical design, design, for example, the physical design of the integrated circuit. This may include determining logic gates, transistors, metal layers, and other necessary items that must be discovered in a physical design such as an integrated circuit. Next, in step 754, optical proximity correction is determined. In one embodiment of the present disclosure, this may include taking a pre-computed character or parameterized character library 776 as input. This may alternatively or additionally include obtaining a pre-designed symbol library 770 comprising complex symbols, which may be retrieved on template 760 in step 762. In an embodiment of the present disclosure, the OPC step 754 may also include simultaneously optimizing the shot count or the number of writes, and may also include a shredding operation, a shot configuration operation, a dose specifying operation, or may also include an optimal firing order. Operation, or other masking material preparation operations, some or all of these operations may be combined simultaneously or in a single step. Once the optical proximity correction is completed, the mask design is developed in step 756.

In step 758, a mask data preparation operation may be performed, which may include a shredding operation, a shot configuration operation, a dose specifying operation, or an optimal firing order. The steps of OPC step 754 or MDP step 758, or separate programs not related to the two steps 754 or 758, may include determining the need to exist A program of a limited number of template symbols or a large number of characters or parameterized characters on a template that can utilize a small number of shots by combining the symbols that need to be present on the template with different doses, positions, and degrees. Partial exposure is performed on the surface by writing all or most of the desired pattern onto the reticle. The present invention contemplates the operation of combining OPC and any or all of the different mask data preparations in one step. A mask data preparation step 758 of shredding operations may be included, which may also include a pattern pairing operation to pair the characters to create a mask that closely fits the mask design. In some embodiments of the present disclosure, the mask data preparation step 758 can include varying the firing dose to produce a peak dose above the interior of the generated pattern at the periphery of the generated pattern. In other embodiments, the resulting shots may create a gap between the shot profiles closest to the adjacent shots such that the area dose is reduced, but the gaps will not be recorded by the mask image 764 that is subsequently produced. In another embodiment, step 758 can include optimizing by varying the gap size. The mask data preparation may also include inputting a pattern to be formed on the surface and a slightly different pattern, and selecting a group to be used to form symbols to form a plurality of patterns, the group of symbols being mounted on the template mask, the group of symbols Including complex and VSB symbols, and the group of symbols is based on a changed symbol dose or a changed symbol position, or a partial exposure is applied to a symbol within the symbol, or a symbol is dragged to Reduce the shot count or total write time. A set of slightly different patterns on the surface can be designed to produce substantially the same pattern on the substrate. Furthermore, the set of symbols can be selected from the symbols of the predetermined group. In a specific embodiment of the disclosure, during the mask writing step 762, a set of symbols that can be obtained on the template in step 770 can be quickly selected, which can be A specific mask design was prepared. In this particular embodiment, once the mask data preparation step 758 is completed, a template is prepared in step 760. In another embodiment of the present disclosure, the template is prepared in step 760 prior to or concurrent with the MDP step 758 and may be independent of the particular mask design. In this particular embodiment, symbols are retrieved in step 770, and the template layout is designed to be output in step 772 for a number of potential mask designs 756 to merge, possibly by a particular OPC program 754 or a particular MDP. The program 758 or the specific form of the characterization design 752 is designed to produce a slightly different pattern of the design, such as a memory, a flash memory, a system on a wafer, or a particular process technology designed for the physical design 752, or The particular cell bank used for the physical design 752, or any other common feature, may come from a slightly different pattern of different sets in the mask design 756. The template may include a set of symbols, such as a limited number of symbols determined in step 758, including a set of adjustment symbols.

Once the template is complete, the template is used to create a surface in a mask writer such as an electron beam writer system. This particular step is defined as step 762. The electron beam writer system projects an electron beam to a surface via the template to form a pattern in a surface, as shown in step 764. The finished surface can then be used in a photolithography machine, which is shown in step 766. Finally, at step 768, a substrate such as a germanium wafer is produced. As previously described, in step 770, a symbol to OPC step 754 or an MDP step 758 may be provided. Step 770 also provides a symbol to symbol and template design step 772 or character generation step 774. Symbol and template design step 772 provides an input to template step 760 and a symbol step 770. Character generation step 774 provides information to the word Step 776 of the character or parameterized character. Again, as already discussed, the character or parametric character step 776 provides information to the OPC step 754 or the MDP step 758.

Referring now to Figure 8, another exemplary process flow diagram 800 for preparing a surface directly written on a substrate such as a germanium wafer is shown. In a first step 802, a physical design, such as a physical design of an integrated circuit, is designed. It can be an ideal pattern that the designer wants to transfer to the substrate. Next, in step 804, various different data preparation (DP) steps are performed including shredding and PEC to prepare input data to the substrate writing device. Step 804 can include fragmentation of the pattern into a complex set of CP and/or VSB shots, wherein portions of the shots can overlap each other. Step 804 can also include inputting a possible character or parameterized character from step 824 based on the predetermined symbol from step 818, and the symbol is used in character generation step 822 to change the symbol dose or change symbol. The calculation of the position or the local exposure of the symbol is determined. Step 804 can also include pattern matching to match the character to produce a wafer image that closely matches the physical design produced in step 802. Pattern substitution, dose designation, and equivalence inspection may also be performed, the iteratively including only one iteration, in which a correct-by-construction "determination" calculation is performed. In some embodiments of the present disclosure, the data preparation step 804 can include changing the firing dose to produce a peak dose above the interior of the generated pattern at the periphery of the generated pattern. In other embodiments, the resulting shots may create a gap between the shot profiles closest to the adjacent shots such that the area dose is reduced, but the gaps will not be recorded by the subsequently generated wafer image 812. In another embodiment, step 804 can include optimizing by varying the gap size. The template is prepared in step 808 and then provided to the wafer writer in step 810. Once the template is complete, the template is used to fabricate wafers in a wafer writer machine such as an electron beam writer system. This step is identified as step 810. An electron beam writer system projects an electron beam through the template onto a surface to form a pattern on the surface. This surface is completed in step 812.

Further, in step 818, a symbol to data preparation and PEC step 804 can be provided. Step 818 also provides a symbol to character generation step 822. The symbol and template design step 820 provides an input to the template step 808 or to the symbol step 818. Symbol step 818 can provide input to symbol and template design step 820. Character generation step 822 provides information to character or parameterized character step 824. The character or parameterized character step 824 provides information to the data preparation and PEC step 804. Step 810 can include repeated application to each of the processing layers as needed, potentially using some of the methods associated with Figure 7, and other methods using the methods outlined above with reference to Figure 8, or using any other crystal. The circular writing method is fabricated to produce an integrated circuit on a germanium wafer.

The shredding, mask data preparation, proximity effect correction, and character generation flow described in the present disclosure can be performed using a general computer having an appropriate computer software as a computing device. Due to the large amount of computation required, most computers or processor cores may also be used in parallel. In a specific embodiment, the calculations may also be subdivided into a plurality of 2-dimensional geometric regions for one or more computational steps of the computational steps in the process to support parallel processing. In another embodiment, the special purpose hardware device, whether single or most Use, can be used to perform one or more steps at a faster rate than a typical computer or processor core. In a specific embodiment, the special purpose hardware device can be a graphics processing unit (GPU). In another embodiment, the optimization and simulation process described in the present disclosure may include modifying and recalculating the iterative process of possible solutions such that the total number of shots or the total charged particle beam write time is minimized, or Some other parameters. In yet another embodiment, the starting shot set can be determined in a correct-by-construction method such that no shot improvement is required.

Although the specification has been described in detail with reference to the specific embodiments thereof, it will be understood that those skilled in the <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; These and other improvements and variations of the method of the present invention for the sizing, masking, and proximity effects are not deviated from the spirit and scope of the subject matter of the present invention as specifically described in the appended claims. , can be implemented by those skilled in the art. In addition, those skilled in the art will understand that the foregoing description is by way of example only and is not intended to be limiting. The steps in the specification may be added, omitted, or modified without departing from the scope of the invention. In general, any flow chart shown is merely intended to indicate one possible order in which the basic operations are functional, and many variations are possible. Therefore, the subject matter of the present invention is intended to cover such modifications and variations within the scope of the appended claims.

100‧‧‧Traditional lithography system, electron beam writer system

112‧‧‧electron beam source, beam source

114, 120, 134‧‧‧ electron beam

116‧‧‧ Orifice

118‧‧‧ hole

122‧‧‧ Orifice or template mask, template

124‧‧‧ openings, holes

126, 126A‧‧‧ symbol

130‧‧‧ surface

132‧‧‧Substrate

136‧‧‧masked area

138‧‧‧Reduction lens

140‧‧‧Reduce electron beam

142‧‧‧ deflector, deflector

148, 252, 602, 610‧‧‧ patterns

150‧‧‧ Positioning agency

202‧‧‧Rectangular pattern, shooting outline

204, 226, 404, 448‧‧‧ lines

210, 220, 410, 420, 430, 440, 450‧‧‧ dose map

212, 230, 412, 422, 432, 442, 452 ‧ ‧ dose curve

214, 414, 424‧‧‧ photoresist threshold

216, 218‧‧‧ dotted line

222, 224, 310~314‧‧‧ shooting profile

302‧‧‧ Polygon pattern

320, 322, 512~526‧‧ shot

324~~3330‧‧‧Interior corner

332‧‧‧Overlapping areas

402, 530‧‧ shot, shooting outline

428‧‧‧Non-zero background exposure

434, 444‧‧‧ threshold

458~459‧‧‧background dose

502‧‧‧Circular pattern

604, 606‧‧‧ square

612~632‧‧‧ shape

640, 670‧‧‧ shooting groups

642~662‧‧‧Towing shot

664~666, 694~696‧‧‧VSB shooting

750, 800‧‧‧ flow chart

752~776, 802~824‧‧‧ steps

1 is a diagram illustrating an embodiment of a symbolized charged particle beam system; Figure 2A illustrates an embodiment of a single charged particle beam shot and a cross-sectional dose map of the shot; Figure 2B illustrates an embodiment of a pair of adjacent shots and a cross-sectional dose map of the shot pair; Figure 2C An embodiment of a pattern formed on a photoresist coated surface from the paired shot of FIG. 2B is illustrated; FIG. 3A illustrates an embodiment of a polygonal pattern; and FIG. 3B illustrates An embodiment of conventional shredding of a polygonal pattern of FIG. 3A; FIG. 3C is an embodiment illustrating alternative shredding of a polygonal pattern of FIG. 3A; and FIG. 4A is an illustration of an implementation of a shooting profile from a rectangular shot Example; Figure 4B illustrates an embodiment of a longitudinal firing curve of a shot taken using Figure 4A of a normal firing dose; Figure 4C illustrates an embodiment of a longitudinal firing curve similar to Figure 4B including a long range effect; The 4D diagram illustrates an embodiment of a longitudinal firing curve shot using a 4A map shot above the normal firing dose; and FIG. 4E illustrates a longitudinal firing curve similar to the 4C plot including the long range effect. An embodiment; FIG. 4F first firing line curve similarly illustrates the longitudinal section of FIG. 4E, but an embodiment with a higher dose level according to the background; FIG. 5A illustrates a system to be formed on the surface of a circular pattern An embodiment; FIG. 5B is an embodiment illustrating the outline of nine shots that can form the pattern of FIG. 5A; FIG. 6A is an illustration of an embodiment including a pattern of two squares before OPC; The figure illustrates an embodiment of a curved pattern that can be made by the OPC process of the pattern of FIG. 6A; and FIG. 6C illustrates how the pattern of FIG. 6B forms a curve by dragging a circular CP shot and a VSB shot. An embodiment of the pattern; FIG. 6D is a diagram illustrating another embodiment of how the pattern of FIG. 6B is formed by dragging a circular CP shot and a VSB shot; FIG. 7 is a diagram illustrating how to prepare for use of light micro A conceptual flow diagram of the fabrication of a surface such as a reticle of a substrate on an integrated circuit on a wafer; and Figure 8 illustrates how to prepare an integrated circuit for use in fabricating, for example, a germanium wafer. A conceptual flow diagram of a surface of a substrate.

100‧‧‧Traditional lithography system, electron beam writer system

112‧‧‧electron beam source, beam source

114‧‧‧Electron beam

116‧‧‧ Orifice

118‧‧‧ hole

120‧‧‧electron beam

122‧‧‧ Orifice or template mask, template

124‧‧‧ openings, holes

126‧‧‧ symbol

126A‧‧‧ symbol

130‧‧‧ surface

132‧‧‧Substrate

134‧‧‧electron beam

136‧‧‧masked area

138‧‧‧Reduction lens

140‧‧‧Reduce electron beam

142‧‧‧ deflector, deflector

148‧‧‧ pattern

150‧‧‧ Positioning agency

Claims (25)

A method for shredding or masking data preparation, comprising the steps of: inputting a desired pattern to be formed on a surface; and determining a set of charged particle beam shots that will form the desired pattern on the surface One of the shots of the set is a tow shot, and wherein the set of shots will produce a peak dose above the desired pattern near the perimeter of the desired pattern. The method of claim 1, wherein the tow shot is used to form a portion of the perimeter of the pattern. A method for shredding or masking data preparation, comprising the steps of: inputting a desired pattern to be formed on a surface; and determining a set of charged particle beam shots that will form the desired pattern on the surface Wherein at least two shots overlap, one of the at least two shots is not the other of the groups, and wherein the set of shots will produce an interior that is higher than the desired pattern near the perimeter of the desired pattern Peak dose. The method of claim 3, wherein the combination of shots in the set of shots does not completely cover the desired pattern. The method of claim 4, wherein the determining step comprises determining a position of the shots such that there is a gap between the closest adjacent shots. For example, the method of claim 5, wherein the decision step is further The step involves the use of an optimization technique in which the dimensions of the gaps are changed. The method of claim 3, wherein the determining step comprises calculating the pattern to be formed on the surface by the group of charged particle beam shots. The method of claim 7, wherein the calculation comprises a charged particle beam simulation. The method of claim 8, wherein the charged particle beam simulation comprises at least one of the group consisting of: forward scattering, backscattering, photoresist diffusion, Coulomb effect, etching, fogging, loading And photoresist charging. The method of claim 3, wherein the set of shots comprises at least one shot of a complex symbol. The method of claim 3, wherein the set of shots comprises a plurality of shots, and wherein each shot is assigned to an exposure in a different exposure history. The method of claim 3, wherein the determining step uses an optimization technique. The method of claim 12, wherein the set of shots comprises a total dose, and wherein the optimization technique reduces the total dose. A system for shredding or masking data preparation, comprising: a device capable of inputting a desired pattern to be formed on a surface; and a device capable of determining a set of shots, the set of shots forming the premises a pattern; wherein one of the set of shots is a tow shot, and wherein the set of shots will produce a peak dose above the desired pattern near the perimeter of the desired pattern. The system of claim 14, wherein the tow shot will form at least a portion of the perimeter of the desired pattern. A system for shredding or masking data preparation, comprising: a device capable of inputting a desired pattern to be formed on a surface; and a device capable of determining a set of shots, the set of shots forming the desired a pattern; wherein at least two shots overlap, any one of the at least two shots is not the other of the groups, and wherein the set of shots will produce an interior that is higher than the desired pattern near the periphery of the desired pattern A peak dose. For example, the system of claim 16 wherein the combination of shots in the set of shots does not completely cover the desired pattern. A system of claim 17, wherein the determinable device creates a gap between the nearest adjacent shots. For example, the system of claim 16 wherein the device capable of determining uses an optimization technique. The system of claim 19, wherein the set of shots comprises a total dose, and wherein the total dose is decreased. For example, the system of claim 16 of the patent scope, wherein the device can be determined The calculation will be performed by the set of shots of the pattern formed on the surface. A system as claimed in claim 21, wherein the calculation comprises a charged particle beam simulation. The system of claim 22, wherein the charged particle beam simulation comprises at least one of the group consisting of: forward scattering, backscattering, photoresist diffusion, Coulomb effect, etching, fogging, loading And photoresist charging. A system as claimed in claim 16, wherein the set of shots comprises at least one complex symbol. A system of claim 16, wherein the set of shots comprises a plurality of shots, and wherein each shot is assigned to an exposure in a different exposure history.