TWI567503B - Method and system for design of enhanced patterns for charged particle beam lithography - Google Patents

Method and system for design of enhanced patterns for charged particle beam lithography Download PDF

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TWI567503B
TWI567503B TW101105804A TW101105804A TWI567503B TW I567503 B TWI567503 B TW I567503B TW 101105804 A TW101105804 A TW 101105804A TW 101105804 A TW101105804 A TW 101105804A TW I567503 B TWI567503 B TW I567503B
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Taiwan
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pattern
shots
shot
dose
surface
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TW101105804A
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TW201245897A (en
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藤村明
萩原和之
史蒂芬F 梅爾
因哥 波克
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D2S公司
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Priority to US13/037,263 priority Critical patent/US20120221985A1/en
Priority to US13/037,270 priority patent/US9057956B2/en
Priority to US13/037,268 priority patent/US20120221980A1/en
Application filed by D2S公司 filed Critical D2S公司
Publication of TW201245897A publication Critical patent/TW201245897A/en
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Description

Method and system for designing enhanced patterns for charged particle beam lithography Related application

This application claims (1) that the application was filed on February 28, 2011, and the invention is entitled "Method and System For Design Of Enhanced Accuracy Patterns for the Design of Enhanced Precision Patterns for Charged Particle Beam Microscopy" Applicant's patent application No. 13/037,268, and (2) February 28, 2011, and the invention entitled "Enhanced Edge Slope Pattern for Charged Particle Beam Microshadowing" US Patent Application Serial No. 13/037,270, the entire disclosure of which is hereby incorporated by reference in its entirety in reference. This patent application is also filed on February 28, 2011, and the title of the invention is "Methods and Systems for Designing Surfaces to Be Manufactured Using Charged Particle Beam Microscopy" (Method and System For Design Of A Surface To Be U.S. Patent Application Serial No. 13/037,263, 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. Conventional photolithography typically uses radiation with a wavelength of 193 nm or longer. Extreme ultraviolet (EUV) or X-ray lithography is also considered a type of photolithography, but the wavelength used is much shorter than the 193 nm of conventional 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 one layer is written directly in On the surface, the surface is also a substrate in this example. 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 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 Shape, nearly annular, elliptical, nearly elliptical, partially circular, partially nearly circular, partially annular, partially proximal, partially nearly elliptical, or any curved shape, and may be a connected complex shape group or a connection A group of most disjointed groups of complex shape groups. 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 the space between circuit devices or interconnects. difference. This design rule is for example used to ensure that the circuit arrangement or line interacts with the other in an undesired manner. 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. Because the critical dimension of the integrated circuit is reduced and its circuit density is increased, the critical dimension of the circuit pattern or physical design approximates the resolution limit of the optical exposure tool used in conventional 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. This analysis of the lithography features and the original pattern in the physical design Interact and interact with each other and compensate for the close effect to improve the circuit pattern that is ultimately transferred. 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. The OPC decoration to be written on the reticle is traditionally discussed from the perspective of the main features. The main feature is Features that are reflected prior to OPC decoration, and OPC features, where 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 traditional mask writing, the dose or shot of electrons is traditionally designed to avoid overlapping as much as possible, so that it can be greatly simplified How the photoresist on the reticle will reveal the calculation of the pattern. Similarly, 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.

In EUV lithography, OPC features are generally not required. Therefore, the complexity of the pattern to be fabricated on the reticle is lower than that of the conventional 193 nm wavelength lithography, and the reduction in the shot count is relatively unimportant. However, in EUV, because of the pattern on the mask, it is typically four times the size of the pattern on the wafer, small enough to challenge the precise formation of charged particle technology using, for example, an E-beam.

There are countless undesired short-range and long-range effects associated with exposure in charged particles. These effects can cause dimensional uncertainty in the pattern that is transferred to, for example, the surface of the reticle. These effects also increase the dimensional change caused by normal process variations in the transfer pattern. What you want to increase the accuracy of the transfer pattern at the same time It also reduces dimensional changes associated with process variations.

Summary of invention

The present invention provides a method and system for shredding or masking data preparation in which overlapping shots are generated to increase the dose in selected portions of the pattern, thereby improving the fidelity and/or critical dimension variation of the transfer pattern. In various embodiments, the improvement may affect the end of the path or line, or a square or near square pattern. The shot may vary in its amount of repetition, the size of the shot, and the dose relative to another overlapping shot dose. The simulation is used to determine the pattern that will be produced on the surface. The invention also discloses a method for making a surface.

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. Embodiments; Figure 4A illustrates an embodiment of a shot profile from a rectangular shot; Figure 4B illustrates an embodiment of a longitudinal shot curve shot using Figure 4A of a normal shot dose; Figure 4C illustrates An embodiment comprising a longitudinal shot curve similar to the long-range effect of Figure 4B; Figure 4D illustrates an embodiment of a longitudinal shot curve shot using a 4A map above the normal shot dose; E is an illustration of an embodiment of a longitudinal firing curve similar to that of a 4C chart that includes a long range of effects; and FIG. 4F is an embodiment that illustrates a longitudinal firing curve similar to that of FIG. 4E but with a higher background dose level; 5A is an illustration of how an 100 nm 2 VSB shot can be seen on a reticle; Figure 5B illustrates an embodiment of how a 60 nm 2 VSB shot can be seen on a reticle; 6A is a diagram illustrating an embodiment of a pattern including an end portion of a line; and FIG. 6B is an embodiment illustrating a conventional single shot method for forming a pattern of FIG. 6A on a surface; FIG. 6C is an illustration An embodiment of a method of forming a pattern of Figure 6A on a surface by an embodiment of the present invention; Figure 6D illustrates the formation of a pattern of Figure 6A on a surface by another embodiment of the present invention An embodiment of the method; FIG. 6E illustrates an embodiment of a method of forming a pattern of FIG. 6A on a surface by another embodiment of the present invention; and FIG. 7 illustrates how to prepare for the preparation Make A conceptual flow diagram of the surface of a substrate such as a pleated mask, such as a substrate on a germanium wafer, fabricated by photolithography; Figure 8 illustrates how to prepare a product for fabrication, for example, on a germanium wafer. Conceptual flow diagram of a surface of a substrate of a bulk circuit; Figure 9A illustrates a square pattern formed on a surface; and Figure 9B illustrates a single shot method for forming a pattern of Figure 9A on a surface; BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates an embodiment of a method of forming a pattern of Figure 9A on a surface by an embodiment of the present invention; Figure 9D illustrates the formation of a surface on a surface by another embodiment of the present invention An embodiment of the method of patterning of Fig. 9A; and Fig. 9E is an illustration of an embodiment of a method of forming a pattern of Fig. 9A on a surface by still another embodiment of the present invention.

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 overlapping shots are produced to improve the accuracy and/or edge slope of the pattern of the written surface. In this patent application, the use of overlapping shots generally increases the shot count and exposure time.

Reference is now made to the drawings in which like reference numerals The diagram illustrates a specific embodiment of a conventional lithography system 100, such as a charged particle beam writer system, in this example an electron beam writer system that applies symbol projection to fabricate 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 a portion of one of the symbols 126, thereby forming a pattern 148, which is a subset of symbol 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 by using an electron beam system One of the 100 shots to depict. 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. In a variation of the conventional 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. Most present The generation of electron beam writer systems achieves effective beam blurring in the range of 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. The partial electron beam writer system performs dose compensation calculations 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 developed 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. The corners of the pattern 202 are rounded due to beam blur. 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 appear in 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 conventional mask writing methodology, the normal dose is set such that, under the absence of long-range effects, a relatively large rectangular shot will appear on the photoresist coated surface, exhibiting a pattern of the desired size. 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 exhibited 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 The second shot appears 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 use of the invention titled "Applied to May 27, 2009" for the purpose of using a variable shape Overlap shots of U.S. Patent Application Serial No. 12/473,265, to Method and System For Design Of A Reticle To Be Manufactured Using Variable Shaped Beam Lithography, An alternative method of forming a pattern 302 on the photoresist coated surface. In Figure 3C, the limits of the shot contours that cannot overlap are eliminated, and shot 320 and shot 322 do overlap. 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 appear to be excessively rounded. Charged particle beam simulation can be used to determine the pattern that appears by photoresist. In a specific embodiment, charged particle beam simulation can be used to calculate the dose for each grid position in a two-dimensional (X and Y) grid, producing 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 change is the standard for the main manufacturing optimization. In today's mask cover technology, you can want to be square Root (RMS) variation does not exceed 1 nm (1σ). More dimensional change conversion circuit performance changes, resulting 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 changes 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 a backscatter that would occur within a single shot of, for example, a backscattering effect of 10 microns, by firing the profile 402, along the dose of line 404. One embodiment of the dose map 410. 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 the exposure of a 428 with a non-zero background to shoot at a normal dose One embodiment of the dose map 420. 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 that appears by the photoresist. Thus, to maintain the size of the photoresist pattern, such as an illustration of the intersection of dose curve 432 and threshold 434, the shot size for dose map 430 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 dose curve 442 is at the x-coordinate due to backscattering. The slopes of "a" and "b" are smaller than the slope of the dose curve 432 at the x-coordinates a" and "b". 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 shot for defining the edge. dose.

FIG. 5A illustrates an embodiment of a square VSB shot 502. In this embodiment, square 502 has a size 504 of 100 nm. Pattern 506 is an embodiment of how shot 502 can be visualized on a photoresist coated surface at a normal dose. As can be seen, the corner 508 of the pattern 506 is rounded due to beam blur. Pattern 506 can be used to form a pattern on a wafer having a size of about 25 nm if formed on a reticle to be used for EUV photolithography using 4x reduced printing. Figure 5B illustrates one embodiment of a smaller square VSB shot 512. In this embodiment, the size 514 of the shot 512 is 60 nm, which is suitable for fabricating a 4x refracting mask for a pattern of 15 nm on a wafer. Pattern 516 is an embodiment of how shot 512 can appear on the photoresist coated surface. As can be seen, the corner rounding effect of the beam blur has caused the appearing pattern to be almost circular. Moreover, although not illustrated, the edge slope of pattern 516 will be less than pattern 506 and may be below a minimum predetermined level to produce an acceptable CD change. Figures 5A and B illustrate how the beam blurring effect becomes more pronounced as the pattern size decreases.

As the process becomes more and more miniaturized, the short-range beam blurring effect becomes a more significant issue for both direct writing and reticle/mask manufacturing. Small geometries also have the problem of edge slope due to the long range effect. The precise fabrication of the minimum line width line with the smallest width line that the manufacturing method can permit can be a challenge using conventional techniques, as shown below. A pattern form that reveals such problems is at the line end, which is a region near the end of the path, wherein the path can have a fixed width, such as an interconnect or a polysilicon in which the polysilicon passes over and spreads over to form a MOS transistor.

Figure 6A illustrates an embodiment of a portion 602 of a line to be formed on a reticle. This portion includes the line end 604. In this embodiment, the width designed on the wafer is 20 nm. A 4x mask is used, so the target width 606 on the pleated mask is 80 nm. Section 6B illustrates an embodiment in which the contour of a single VSB shot 614 that is conventionally used to form a pattern on a reticle can be used. FIG. 6B also illustrates a pattern 618 formed on the reticle by shot 614. As can be seen, the corners of the line end pattern 618 are significantly rounded. A portion 619 of the perimeter of pattern 618 is illustrated with a dashed line indicating that the perimeter portion has an edge slope that is less than a predetermined minimum. Figure 6C is a diagram illustrating an embodiment of a method for forming a pattern 602 in accordance with the present invention. In FIG. 6C, two shots are used to expose line end patterns 602: shot 624 and shot 625, which overlap with shot 624. Shot 624 uses a higher than normal dose. The extra shot 625 provides an additional peak dose near the line end. If the specified firing dose permits, shot 625 uses a dose lower than shot 624, and multiple exposures can be used with shot 625 to group an exposure operation having a lower dose than the exposure operation using shot 624. The two shots 624 and 625 can create a pattern 628 on the reticle, wherein the corners of the pattern 628 are less rounded than the corners of the pattern 618. The dashed portion 629 of the perimeter of the pattern 628 is shorter than the dashed portion 619 of the pattern 618, since the pattern 628 has a higher line end exposure than the pattern 618, indicating a modified line end edge slope in the pattern 628.

Figure 6D illustrates another embodiment of the present invention that uses three shots to form the line end 604 of the pattern 602. Shot 634 is similar to shot 624 of Figure 6C, using a higher than normal dose. In addition, shooting 635 and shooting 636 with The shots 634 overlap and add additional peak doses near the corners of the line ends. Shots 635 and 636 may have a lower dose than shot 634. Shots 635 and 636 can be illustrated by such an embodiment, extending beyond the contour of shot 634 and the outline of original pattern 602. Again, the illustrated shapes 635 and 636 can be fired with individual VSB shots, or if the complex CP symbol is designed to have two illustrated shapes 635 and 636, fired at a single CP. The three VSB shots 634, 635 and 636, or if a CP shot is used to fire the two shots of the illustrated shapes 635 and 636, a pattern 638 can be created on the reticle, wherein the pattern 638 corner is formed by a pattern formed by two shots The corner of the 628 is less rounded. Moreover, the lower edge slope portion 639 of the perimeter of the pattern 638 is smaller than the perimeter portion 629 of the pattern 628. Figure 6D illustrates how a large number of shots can be used to form a line end pattern that more accurately achieves the desired shape and has a higher edge slope.

Figure 6E is a diagram illustrating another embodiment of the present invention using four shots to form the line end 604 of the pattern 602. In addition to the main shot 644, two corner shots 645 and 646 having a higher than normal dose can be used, and shot 647 increases the exposure of the mid-end of the line end. The dose of shot 647 can be less than the dose of shots 645 and 646. Shot 647 allows the dose in the middle of the line end to be adjusted independently of the dose at the corner of the line end. Pattern 648 illustrates the pattern that shots 644, 645, 646, and 647 can produce on the reticle. In the pattern 648, the peripheral portion 649 having a slope below the minimum edge is slightly smaller than the peripheral portion 639 of the 6D map. Moreover, if such shapes are designed and fabricated on the stencil, the illustrated shapes 645 and 646 can be fired with a single complex CP symbol shot.

Figure 6C-E illustrates how a group of shots can be modified with overlapping shots. Producing a small area near the high peak dose of the line end improves both the accuracy and edge slope of the pattern produced on the reticle. Only small areas are exposed at higher than normal doses, with less increase in backscatter if the entire pattern is used above normal doses. The shooting system is modified using a shot change technique that includes changing one or all shot doses, overlapping configurations, and overlapping shot sizes. Particle beam simulation can be used to determine the effect of a set of shots and the dose that will be produced on the surface of the reticle.

The 9A-D diagram illustrates the use of overlapping shots for, for example, square patterns of contact and via patterns typically used in integrated circuit designs. Figure 9A illustrates an embodiment of a desired pattern 902 to be formed on a reticle. FIG. 9B illustrates a single VSB shot 912 that is conventionally used to form pattern 902. However, for small patterns, the use of a single VSB shot 912 can result in rounding of the corners, similar to the rounding of the corners of the pattern 61 illustrated in Figure 6B. Also similar to pattern 618, the use of a single shot 912 can cause the edge slope to be undesirably low. Figure 9C illustrates a specific embodiment of the present invention for forming a square or near square pattern. Five VSB shots can be used, including to identify shots 922 drawn in cross-hatching, and four VSB corner shots 924 that overlap the corners of shot 922. Alternatively, all four illustrated corner shapes 924 can be designed as a single complex CP symbol on the template, allowing the embodiment of Figure 9C to apply a VSB shot 922 and a CP shot 924 for shooting. As in the construction of line-end shots in Figure 6D, adding corner shots to increase the peak dose near the corners of the pattern improves the fidelity of the transfer pattern and also improves the edge slope near the corners of the transfer pattern, thereby reducing CD variations. .

Figure 9D is a diagram illustrating an example of another embodiment of the present invention. Similar to the shot construction of Figure 9C, the 9D map can be fired using a five VSB shot, including shot 932, which is drawn in cross-hatching, and four additional shots 934 surrounding the perimeter of the original pattern 902. Also similar to Figure 9C, the CP symbols can be designed to expose the pattern illustrated by the four rectangles 934 with a single CP shot, and for the four shapes 934, the 9D map is allowed to be exposed with a VSB shot 932 and a CP shot. The use of peripheral CP shots or VSB shots can increase the edge slope around the entire transfer pattern of the transfer pattern by increasing the peak dose near the perimeter. Small peripheral CP shots or VSB shots do not increase the amount of the regional dose as high as the higher dose used for shot 932, as compared to the higher dose shot 932 alone, the backscatter is reduced.

Figure 9E is a diagram illustrating an example of another embodiment of the present invention. Nine regions are illustrated in Figure 9E: (a) large area 942, (b) four side areas 944, and (c) four corner areas 948. As seen, all regions 944 and 948 overlap with region 942. These areas can be exposed by any of the following methods:

. Nine separate VSB shots, including one shot for area 942, four shots for four areas 944, and four shots for four corner areas 948.

. Five VSB shots. Area 942 is exposed by a shot. For the remaining four VSB shots, each shot includes a side region 944 and a union of two corner regions 948 of the side regions of the two neighbors. This provides a higher dose in the corner than the dose along the side. Additional peak exposure near the corner provides improved accuracy and/or edge slope.

. One VSB shot for area 942 and two CP shots - two CP symbols each for one shot. A CP symbol can be designed to include, for example, four side regions 944 and a second CP symbol that can be designed to include a four corner region 948. This solution allows for independent dose control of the corner regions and non-corner side regions.

The method of using a VSB shot with two CP shots should require nine shots of the VSB or five shots of the VSB method with less exposure time. Additionally, the size of the shot 942 can be adjusted to be smaller than the desired pattern 902.

The method of the present invention can also be applied to processes using rectangular contacts and/or vias. For a rectangular pattern having an aspect ratio of about 1:1.5 or less, the method illustrated in Figure 9D can be used. For a rectangular pattern having a large aspect ratio, each end of the longer axis of the rectangular pattern can be considered a line end. The above-described solution described in Fig. 9C can be carried out even if a charged particle beam system that does not allow the dose specification of individual shots is used. In one embodiment of the invention, a small number of doses can be selected, such as a 1.0x normal dose and a 0.6x normal dose, and the individual shots of the two doses can be separated and exposed in two separate exposure operations, one of which is an exposure operation The base dose is 1.0 x normal dose and the base dose for another exposure operation is 0.6 x normal dose. In the example of Figure 9C, shot 922 can be assigned to a first exposure operation that uses a base dose of 1.0 x normal dose prior to PEC correction. Four shots 924 can be assigned to a second exposure operation that uses a base dose of 0.6x normal dose prior to PEC correction. Thus, even with a charged particle beam writer that cannot specify a dose for individual shots, overlapping shots can produce a pattern dose that is greater than 100% of the normal dose.

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 can be used as input during pattern shredding in a design. For example, referring again to FIG. 9D, a dose map of a combination of shot 932 and four shots 934 can be calculated and stored in a character library. If during the shredding, one of the input patterns is a square pattern of the same size as the pattern 902, the character of the pattern 902 and the five shots containing the character can be taken out of the library, and the appropriate shot group that determines the square input pattern is avoided. Calculating labor. Characters can also contain CP shots and can contain dragged CP or VSB shots. A series of characters can also be combined to produce parameterized characters. The parameters can be discontinuous or continuous. For example, shots and dose maps for forming a square pattern, such as square pattern 902, 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 pre-designed symbols including complex symbols. Metabase 770 is taken as input, 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 unrelated to the two steps 754 or 758, may include a program that determines the presence of a limited number of template symbols or a large number of characters or parameterized characters on the template. The characters can be shot with a small number of shots by combining the symbols that need to be present on the template with local exposures of different doses, positions and degrees to write all or most of the desired pattern on the reticle. On the surface. 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 generating overlapping shots to produce a higher peak dose near the line end or near the perimeter of the square or near square pattern. 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 one embodiment of the present disclosure, a set of symbols that can be taken on the template in step 770 can be quickly selected during the mask writing step 762, which can be prepared for a particular mask design. 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. An electron beam writer system projects an electron beam to a surface via the template Forming a pattern in a surface is 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. The character generation step 774 provides step 776 of information to characters or parameterized characters. 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 matching, iterative designation, and equivalent inspection may also be performed, the iterative potentially including only one Iterative, in which the correct-by-construction "determination" calculation is performed. In some embodiments of the present disclosure, the data preparation step 804 can include overlapping shots near or near the line end of a square or near square pattern. 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 can also be subdivided into a number 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, special purpose hardware devices, whether used singly or in combination, 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 group can be determined in a correct-by-construction method such that no shot modification 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 modifications and variations of the present invention for the method of sizing, masking, and singularity of the present invention are not departing 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 the modifications and variations of the scope of the appended claims.

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

202‧‧‧Rectangular pattern, shooting outline

204‧‧‧ lines

210‧‧‧Dose map

212‧‧‧Dose curve

214‧‧‧ photoresist threshold

216‧‧‧dotted line

218‧‧‧ dotted line

222‧‧‧ Shooting profile

224‧‧‧ Shooting outline

226‧‧‧ lines

230‧‧‧Dose curve

252‧‧‧ pattern

302‧‧‧ Polygon pattern

310‧‧‧ Shooting profile

312‧‧‧ Shooting outline

314‧‧‧ Shooting profile

320‧‧‧ Shooting

322‧‧‧ shooting

324‧‧‧ interior corner

326‧‧‧ interior corner

328‧‧‧ interior corner

330‧‧‧ interior corner

332‧‧‧Overlapping areas

402‧‧‧ Shooting, shooting silhouette

404‧‧‧ lines

410‧‧‧Dose map

412‧‧‧Dose curve

414‧‧‧resistance threshold

420‧‧‧Dose map

422‧‧‧Dose curve

424‧‧‧resistance threshold

428‧‧‧Non-zero background exposure

430‧‧‧Dose map

432‧‧‧Dose curve

434‧‧‧ threshold

440‧‧‧Dose map

442‧‧‧Dose curve

444‧‧‧ threshold

448‧‧‧ lines

450‧‧‧Dose map

452‧‧‧Dose curve

458‧‧‧ background dose

459‧‧‧Background dose

502‧‧‧Square VSD shooting

504‧‧‧ size

506‧‧‧ pattern

508‧‧‧ corner

512‧‧‧Square VSB shooting

514‧‧‧ size

516‧‧‧ pattern

602‧‧‧ pattern, part of the line

604‧‧‧ line side

606‧‧‧Width

614‧‧ shot

618‧‧‧ pattern

Part of the surrounding 619‧‧

624‧‧‧ shooting

625‧‧‧ shooting

628‧‧‧pattern

629‧‧‧dotted part, peripheral part

634‧‧‧ Shooting

635‧‧‧ shooting

636‧‧‧ Shooting

638‧‧‧pattern

639‧‧‧ Lower edge slope section

644‧‧‧ main shooting

645‧‧‧ corner shooting

646‧‧‧ corner shooting

647‧‧‧ shooting

648‧‧‧ pattern

649‧‧‧ peripheral parts

750‧‧‧flow chart

752‧‧‧Steps

754‧‧‧Steps

756‧‧ steps

758‧‧‧Steps

760‧‧‧Steps

762‧‧‧Steps

764‧‧‧Steps

766‧‧‧Steps

768‧‧‧Steps

770‧‧‧Steps

772‧‧‧Steps

774‧‧‧Steps

776‧‧‧Steps

800‧‧‧ Flowchart

802‧‧ steps

804‧‧‧ steps

806‧‧‧Steps

808‧‧‧Steps

810‧‧‧Steps

812‧‧‧ steps

818‧‧‧Steps

820‧‧‧Steps

822‧‧‧Steps

824‧‧‧Steps

902‧‧‧ desired pattern

912‧‧ shot

922‧‧‧ shooting

924‧‧‧ shooting

932‧‧ shot

934‧‧‧ Shooting, rectangular

942‧‧‧Great area

944‧‧‧Side area

948‧‧‧ corner area

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. Embodiments; Figure 4A illustrates an embodiment of a shot profile from a rectangular shot; Figure 4B illustrates an embodiment of a longitudinal shot curve shot using Figure 4A of a normal shot dose; Figure 4C An embodiment is illustrated that includes a longitudinal shot curve similar to that of Figure 4B for a long range of effects; and FIG. 4D illustrates an embodiment of a longitudinal shot curve shot using a 4A map above the normal shot dose; 4E is a diagram illustrating an embodiment of a longitudinal firing curve similar to the 4C chart of the long range effect; FIG. 4F is an embodiment illustrating a longitudinal firing curve similar to FIG. 4E but having a higher background dose level; Figure 5A illustrates an embodiment of how a 100 nm 2 VSB shot can be recorded on a reticle; Figure 5B illustrates an embodiment of how a 60 nm 2 VSB shot can be recorded on a reticle Fig. 6A is an embodiment illustrating a pattern including an end portion of a line; Fig. 6B is an embodiment illustrating a conventional single shooting method for forming a pattern of Fig. 6A on a surface; An embodiment of a method of forming a pattern of Figure 6A on a surface by an embodiment of the present invention is illustrated; Figure 6D illustrates the formation of Figure 6A on a surface by another embodiment of the present invention. An embodiment of a method of patterning; FIG. 6E is a diagram illustrating an embodiment of a method of forming a pattern of FIG. 6A on a surface by another embodiment of the present invention; and FIG. 7 is a diagram illustrating how to prepare use A conceptual flow diagram of the surface of a substrate, such as a pleated refractory, used to fabricate an integrated circuit, such as a germanium wafer, using photolithography; FIG. 8 is a diagram illustrating how to prepare for fabrication, for example, on a germanium wafer. a conceptual flow diagram of a surface of a substrate of an integrated circuit; FIG. 9A illustrates a square pattern formed on a surface; and FIG. 9B illustrates a single shot method for forming a pattern of FIG. 9A on a surface; 9C is a diagram illustrating an embodiment of a method of forming a pattern of FIG. 9A on a surface by an embodiment of the present invention; and FIG. 9D is a diagram illustrating formation on a surface by another embodiment of the present invention. An embodiment of the method of patterning of Fig. 9A; and Fig. 9E is an illustration of an embodiment of a method of forming a pattern of Fig. 9A on a surface by still another embodiment of the present invention.

644‧‧‧ main shooting

645‧‧‧ corner shooting

646‧‧‧ corner shooting

647‧‧‧ shooting

648‧‧‧ pattern

649‧‧‧ peripheral parts

Claims (24)

  1. A method for shredding or masking data preparation or proximity effect correction, comprising: calculating a line end pattern to be produced on a photoresist coated surface, and calculating a charged particle beam write from a shape for electron beam The slope of the edge of the line end pattern of one of the original shots; and modifying the original set of shots by increasing a dose delivered to the surface near the line end to improve the calculated edge of the line end pattern The slope is such that the surface dose near the line end is higher than a normal dose, wherein the modifying step comprises at least one of the group consisting of: (1) determining an additional overlap with one of the shots of the set of shots Shooting; (2) changing the overlap of two or more shots in the set of shots; (3) changing the size of one shot that overlaps another shot; and (4) making another overlap shot relative to the set of shots a dose to change the dose of one of the shots of the set, wherein the photoresist comprises a photoresist threshold, and wherein the edge slope is included in the photoresist threshold and the surface dose is perpendicular to the perimeter of the pattern The slope of the linear dimensions; precalculation and input one character library, wherein the step of determining determines from the one or more shots of characters, the characters and wherein the step of forming at least a portion of the pre-calculation of the pattern is calculated.
  2. The method of claim 1, wherein the calculating step comprises a charged particle beam simulation.
  3. The method of claim 2, 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.
  4. The method of claim 1, wherein the modified set of shots comprises a symbol projection shot of a complex symbol.
  5. The method of claim 1, wherein the modified set of shots increases the peak dose near the line end.
  6. A method for shredding or masking data preparation or proximity effect correction, comprising: determining a plurality of shots for a shaped electron beam charged particle beam writer, wherein the plurality of shots are coated in a photoresist Forming a line end pattern on the surface, wherein the determining step includes calculating the pattern on the surface, and calculating an edge slope of the pattern from the plurality of shots, and wherein the edge slope of the line end pattern on the surface is Improved using a shot change technique that includes at least one of the group consisting of: (1) changing the dose of one shot that overlaps another shot; (2) changing two or more shots. And (3) changing the size of one of the shots that overlaps another shot; wherein the photoresist comprises a threshold, and wherein the edge slope comprises a calculated dose on the surface of the photoresist threshold relative to the surface a slope of one of the linear dimensions of the perimeter of the pattern, and wherein the shot change technique produces a pattern dose that is higher than a normal dose of one of the line ends; and one of the input pre-calculations Symbol library, wherein the step of determining determines from the one or more shots of characters, the characters and wherein the step of forming at least a portion of the pre-calculation of the pattern is calculated.
  7. The method of claim 6, wherein the determining step comprises determining the plurality of exposures Light operated shots, as well as overlapping shots, are placed in different exposure operations.
  8. The method of claim 6, wherein a complex symbol shot is determined.
  9. The method of claim 6, wherein an optimization technique is used to determine the plurality of shots.
  10. The method of claim 6, wherein the calculating step comprises charged particle beam simulation.
  11. A method for shredding or masking data preparation or proximity effect correction, comprising: determining a plurality of shots for a shaped electron beam charged particle beam writer, wherein the plurality of shots are coated in a photoresist Forming a square or nearly square pattern on the surface, wherein the determining step includes calculating the pattern on the surface, and calculating an edge slope of the pattern from the plurality of shots, and wherein the pattern of the square on the surface The edge slope is improved using a shot change technique that includes at least one of the group consisting of: (1) changing the dose of one shot that overlaps another shot; (2) changing two And the overlap of more shots; and (3) changing the size of one shot that overlaps another shot; wherein the photoresist comprises a photoresist threshold, and wherein the slope of the edge is included on the surface of the photoresist threshold a slope of a linear dimension relative to a perimeter of the pattern on the surface, and wherein the shot changing technique produces a normal dose of the perimeter that is closer to the pattern Dose of a pattern; and an input character one precomputed library, wherein the step of determining determines from the one or more shots of characters, and wherein the step of forming at least a character precomputed Part of the pattern calculation.
  12. The method of claim 11, wherein the calculating step comprises charged particle beam simulation.
  13. The method of claim 11, wherein the plurality of shots produce a peak dose above the center of the pattern near a corner of the pattern.
  14. A method for fabricating a photoresist coated surface, comprising: determining a plurality of shots for a shaped electron beam charged particle beam writer, wherein the plurality of shots will form a line end pattern on a surface, The determining step includes calculating the pattern on the surface, and calculating an edge slope of the pattern from the plurality of shots, and wherein the edge slope of the line end pattern on the surface is improved using a shot change technique, The shot change technique includes at least one of the group consisting of: (1) changing the dose of one shot that overlaps another shot; (2) changing the overlap of two or more shots; and (3) Changing a size of one of the shots that overlaps another shot; wherein the shot change technique produces a pattern dose that is higher than a normal dose of one of the line ends, wherein the photoresist comprises a photoresist threshold, and wherein the edge slope comprises a slope of a calculated dose on the surface of the photoresist threshold relative to a linear dimension perpendicular to the perimeter of the pattern on the surface; inputting a pre-computed library of characters, wherein Step decision from a shot or more characters, and wherein the step of precomputed characters constituting at least a portion of the pattern is calculated; and using a plurality of charged particle beams form the firing end of the line pattern on the surface.
  15. The method of claim 14, wherein the determining step comprises determining a shot for the multiple exposure operation, and wherein the overlapping shots are placed in different exposure operations.
  16. The method of claim 14, wherein the set of shots comprises a complex symbol.
  17. The method of claim 14, wherein the calculating step comprises charging a particle beam simulation.
  18. A method for fabricating a photoresist coated surface, comprising: determining a plurality of shots for a shaped electron beam charged particle beam writer, wherein the plurality of shots form a square or approximately square on a surface a pattern, wherein the determining step includes calculating the pattern on the surface, and calculating an edge slope of the pattern from the plurality of shots, and wherein the edge slope of the pattern on the surface is improved using a shot change technique, The shot change technique includes at least one of the group consisting of: (1) changing the dose of one shot that overlaps another shot; (2) changing the overlap of two or more shots; and (3) Changing a size of one of the shots that overlaps another shot; wherein the shot change technique produces a pattern dose that is higher than a normal dose of one of the perimeters of the pattern, wherein the photoresist comprises a photoresist threshold, and wherein the edge slope a slope of a calculated dose on the surface of the photoresist threshold relative to a linear dimension perpendicular to the perimeter of the pattern on the surface; inputting a pre-computed character Wherein the step of determining determines from the one or more shots of characters, the characters and wherein the step of forming at least a portion of the pre-calculation of the pattern is calculated; and using the charged particle beam writer and such plurality of shot in the table The square or approximately square pattern is formed on the face.
  19. A system for shredding or masking data preparation or proximity effect correction, comprising: a device capable of determining a plurality of charged particle beam shots, the plurality of charged particle beam shots being formed on a photoresist coated surface a line end pattern, wherein the means for determining the ability comprises means for calculating the pattern on the surface and calculating the slope of the edge of the pattern from the plurality of shots, and wherein the line end pattern on the surface The edge slope is modified using a shot change technique that includes at least one of the group consisting of: (1) changing the dose of one shot that overlaps another shot; (2) changing The overlap of two or more shots; and (3) changing the size of one shot that overlaps another shot, wherein the shot change technique produces a pattern dose that is higher than a normal dose of one of the line ends, wherein the photoresist A photoresist threshold is included, and wherein the edge slope comprises a calculated dose on the surface of the photoresist threshold relative to a linear scale perpendicular to a perimeter of the pattern on the surface Slope; and a means capable of inputting one character library expected operator, wherein the step of determining determines from the one or more shots of characters, the characters and wherein the step of forming at least a portion of the pre-calculation of the pattern is calculated.
  20. The system of claim 19, wherein the device having computing power performs a charged particle beam simulation.
  21. The system of claim 20, 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.
  22. The system of claim 19, wherein the device having computing power uses an optimization technique.
  23. A system for shredding or masking data preparation or proximity effect correction, comprising: a device capable of determining a plurality of charged particle beam shots, the plurality of charged particle beam shots forming a square or approximation on a surface a pattern of squares, wherein the device having determining ability comprises a device capable of calculating the pattern on the surface and calculating a slope of an edge of the pattern from the plurality of shots, and wherein the pattern of the square on the surface The edge slope is improved using a shot change technique that includes at least one of the group consisting of: (1) changing the dose of one shot that overlaps another shot; (2) changing two And the overlap of more shots; and (3) changing the size of one shot that overlaps another shot, wherein the shot change technique produces a pattern dose that is higher than a normal dose of one of the perimeters of the pattern, wherein the photoresist Including a photoresist threshold, and wherein the edge slope includes a calculated dose on the surface of the photoresist threshold relative to the circumference of the pattern on the surface One of the vertical slope of the linear dimensions; and a means capable of inputting one character library expected operator, wherein the determining step determines at least a portion of the pattern is calculated from the configuration of one or more shots of characters, the characters and wherein the step of pre-computed.
  24. The system of claim 23, wherein the device having computing power performs a charged particle beam simulation.
TW101105804A 2011-02-28 2012-02-22 Method and system for design of enhanced patterns for charged particle beam lithography TWI567503B (en)

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US13/037,263 US20120221985A1 (en) 2011-02-28 2011-02-28 Method and system for design of a surface to be manufactured using charged particle beam lithography
US13/037,270 US9057956B2 (en) 2011-02-28 2011-02-28 Method and system for design of enhanced edge slope patterns for charged particle beam lithography
US13/037,268 US20120221980A1 (en) 2011-02-28 2011-02-28 Method and system for design of enhanced accuracy patterns for charged particle beam lithography

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6610989B1 (en) * 1999-05-31 2003-08-26 Fujitsu Limited Proximity effect correction method for charged particle beam exposure
US20090325085A1 (en) * 2006-11-21 2009-12-31 D2S, Inc. Stencil design and method for improving character density for cell projection charged particle beam lithography
US20100058281A1 (en) * 2008-09-01 2010-03-04 D2S, Inc. Method for optical proximity correction of a reticle to be manufactured using character projection lithography
US20100055585A1 (en) * 2008-09-01 2010-03-04 D2S, Inc. Method for Optical Proximity Correction of a Reticle to be Manufactured Using Variable Shaped Beam Lithography

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6610989B1 (en) * 1999-05-31 2003-08-26 Fujitsu Limited Proximity effect correction method for charged particle beam exposure
US20090325085A1 (en) * 2006-11-21 2009-12-31 D2S, Inc. Stencil design and method for improving character density for cell projection charged particle beam lithography
US20100058281A1 (en) * 2008-09-01 2010-03-04 D2S, Inc. Method for optical proximity correction of a reticle to be manufactured using character projection lithography
US20100055585A1 (en) * 2008-09-01 2010-03-04 D2S, Inc. Method for Optical Proximity Correction of a Reticle to be Manufactured Using Variable Shaped Beam Lithography

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