TWI506672B - Method for fracturing and forming circular patterns on a surface and for manufacturing a semiconductor device - Google Patents

Description

Method for shredding and forming a circular pattern on a surface and for manufacturing a semiconductor device Related application

This application is hereby incorporated by reference in its entirety in its entirety, the entire disclosure of the entire disclosure of the entire disclosure of the entire disclosure of U.S. Patent Application Serial No. 12/540,322, entitled "Method and System for Forming a Circular Pattern on a Surface", and Application No. 12/540,322, filed on September 12, 2008, entitled "Using U.S. Patent Application Serial No. 12/202,364, the disclosure of which is incorporated herein by reference. Method of manufacturing a surface and integrated circuit"; and 5) US Patent Provisional Application entitled "Method and System for Making Circular Patterns on a Surface and Integrated Circuit", filed on July 10, 2009 Priority to 61/224,849, all of which are hereby incorporated by reference.

This invention relates to methods for surface fragmentation and formation of circular patterns and for the fabrication of semiconductor devices.

Background of the invention

The present disclosure relates to lithography, and more particularly to the design and fabrication of a surface using charged particle beam lithography, which may be a reticle, a wafer, or any other surface.

In the production and manufacture of semiconductor devices such as integrated circuits, such semiconductor devices can be fabricated using optical lithography. Optical lithography is a printing process in which a lithography mask or a reticle is used to transfer a pattern to a substrate such as a semiconductor or a germanium wafer to produce a product. Body circuit. Other substrates can include flat panel displays or even other reticle. In addition, ultra-ultraviolet light (EUV) or X-ray lithography is a type of optical lithography. The reticle or the plurality of reticle can include a circuit pattern corresponding to an individual layer of the integrated circuit, and the pattern can be imaged onto a specific area on the substrate coated with a layer of light known as light Radiation sensitive material for resists (photoresist or resist). Once the patterned layer is transferred, the layer is capable of various other procedures such as etching, ion implantation (doping), metallization, oxidation, and grinding. These programs are used to complete a separate layer in the substrate. If several layers are required, the programs or their variations will be repeated for each new layer. Finally, a combination of multiple devices or integrated circuits will be formed on the substrate. These integrated circuits can then be separated from one another by dicing or sawing and can then be placed into individual packages. In a more general case, the pattern on the substrate can be used to define an artificial product such as a display pixel or a recording head.

In the production and manufacture of semiconductor devices such as integrated circuits, such semiconductor devices can also be fabricated using a maskless direct writing method. Unmasked direct writing is a printing process in which a 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 can include flat panel displays, embossed masks for nanoimprinting, or even reticle. The desired pattern of one layer is written directly on the surface, which in this case is also the substrate. Once the patterned layer has been transferred, the layer is capable of various other procedures such as etching, ion implantation (doping), metallization, oxidation, and grinding. These programs are used to complete a separate layer in the substrate. If several layers are required, the entire program or its variations will be repeated for each new layer. Some of these layers can be written using optical lithography, while other layers can be written using unmasked direct writing to create the same substrate. Finally, a combination of multiple devices or integrated circuits is formed on the substrate. These integrated circuits can then be separated from one another by cutting or sawing and can then be placed into individual packages. In a more general case, the pattern on the substrate can be used to define an artificial product such as a display pixel or a recording head.

In semiconductor manufacturing, reliable fabrication of contacts and vias is quite difficult and important, especially when optical lithography is used to create patterns of less than 80 nm half pitch, where the half pitch is one-half Minimum contact or via size plus one-half contact or minimum required spacing between vias. The contacts and vias connect one of the conductive materials on one layer to the conductive material on the other. In prior art nodes that are relatively large in today's commonly used technology nodes, attempts have been made to make square vias and contacts on the wafer. Square contacts and vias are required to maximize the area of connection between the conductive material located in the underlying layer and the conductive material located in the upper layer. But as character size is reduced, the creation of a large number of square patterns on a semiconductor wafer becomes expensive or infeasible. In particular, a half pitch of 80 nm or less, viewed from above, the semiconductor manufacturer's goal is to form an approximately circular shape on the wafer that produces approximately cylindrical contacts or vias. The design data for the desired wafer shape still sets the desired shape as a square. However, manufacturers and designers expect that the limitations of the optical lithography procedure will cause the shape actually produced on the wafer to become an approximately circular shape. For all shapes, the general case of this effect is sometimes referred to as a corner guide.

Conventionally, one of the advantages of designing a contact and a through hole as a square in terms of design data is that a square pattern can be formed relatively quickly on a reticle. However, the use of a square pattern for the contacts and vias located on the reticle makes it more difficult to fabricate vias and contacts on the semiconductor device. The exclusion of the use of square patterns on the reticle for the difficulties associated with the contacts is advantageous, especially for half pitches less than 80 nm.

Summary of invention

A method for fabricating a semiconductor device using a photomask and optical lithography, wherein a circular pattern on the semiconductor wafer is formed by using a circular pattern on a photomask, which is charged The particle beam writer is manufactured. In one embodiment, the variable size circular pattern is formed on the reticle using a single character projection (CP) character to change the charged particle beam dose.

Also disclosed is a method for illuminating a shredded circular pattern using a circular CP character or using a variable shape beam (VSB), wherein the plurality of combinations of VSB illumination are different from the desired pattern set.

Also disclosed is a method for forming a circular pattern on a surface using a one-character projection (CP) charged particle beam writer, wherein circular patterns of different sizes can be formed using a single CP character by varying the dose. .

Also disclosed is a method for forming a circular pattern on a surface using a variable shape beam (VSB) charged particle beam writer, wherein the dose of illumination can be varied, and wherein the combination of illumination is different from the target pattern group .

Also disclosed is a method for forming a circular pattern on a surface using a pattern library, wherein the pattern is a pre-calculated dose map derived from one or more charged particle beam illuminations.

These and other advantages of the present invention will become apparent from the Detailed Description of the Drawing.

Simple illustration

Figure 1 shows a conventional method of forming a circular pattern such as a contact or a via on a wafer;

Figure 2 shows a method of forming a circular pattern such as a contact or a via on a wafer by the present invention;

Figure 3 shows a charged particle beam writer with character projection (CP) capability;

Figure 4 shows a character projection template containing one of a plurality of circular characters;

Figure 5A shows a pattern formed by illumination of a circular character projection character;

Figure 5B shows the effect of changing the dose on the size of the pattern aligned on the surface by the projection projection of the character of Figure 5A;

Figure 6 shows a flow chart showing the range of diameters of a circular pattern that can be formed on a surface using a set of circular character projection characters;

Figure 7 shows how overlapping VSB illumination can be utilized to write a circular pattern;

Figure 8 shows how non-overlapping VSB illumination can be utilized to write a circular pattern;

Figure 9 shows that a parametric pattern can be used to create a circular pattern on a surface;

Figure 10 is a conceptual flow diagram showing the fabrication of a reticle and the fabrication of an integrated circuit using an exemplary method of the present invention;

Figure 11A shows a pattern of one of the desired approximate circles;

Figure 11B shows a set of non-overlapping VSB illuminations capable of forming the pattern of Figure 11A.

Detailed description of the preferred embodiment

Figure 1 shows a conventional method for forming contacts and via patterns on a wafer using optical lithography. An optical lithography machine 100 includes an illumination source 102 that emits optical radiation onto a reticle 104 that includes a plurality of rectangular aperture patterns 106. Optical radiation is transmitted through the aperture pattern 106 and through one or more lenses 108 to form a pattern 110 on a surface 112 such as a semiconductor wafer. In general, the pattern 110 on the surface 112 is typically smaller in size than the aperture pattern 106 on the reticle 104. Due to limitations of the optical lithography procedure, such as the wavelength of radiation produced by the illumination source 102, for small contacts and vias such as patterns of less than 80 nanometers half pitch, the square pattern on the reticle will A circular or approximately circular pattern is formed on the substrate.

In semiconductor lithography, there is an important concept called the mask error enhancement factor (MEEF). In a typical semiconductor fabrication process using a reticle, the reticle is four times the size of the wafer. For example, a target shape of 50 nm on a surface would have a shape of 200 nm on the reticle. If the MEEF is 1.0, a 4 nm offset error on the mask will change to a 1 nm offset on the wafer. However, for a line segment and space such as on an interconnect or wiring layer, a typical MEEF is 2. For the connection layer, a typical MEEF is 4, which means that a 4 nm offset error on the reticle is converted to a 4 nm offset on the wafer. In the case of advanced technology nodes with a contact layer of less than 80 nm half pitch, it is possible to project MEEFs of up to 10. In this case, a 4 nm offset on the reticle translates into a 10 nm offset on the wafer. The reticle, and especially the reticle of the contact layer, must be extremely precise so that the error in multiplying the MEEF on the surface does not exceed the maximum tolerance.

One known method for improving MEEF is the so-called perimeter rule. The rule of circumference states that for a particular closed shape, a higher shape perimeter will result in a larger MEEF for the shape to area ratio. In semiconductor manufacturing, the most important step in lithography is to expose the photoresist with the correct amount of total energy for each shape on the reticle. Thus, for each pattern or shape, the accuracy requirements for the total area are greater than the other dimensions of the pattern or shape. The source of error in various semiconductor fabrication processes acts on the perimeter, which is the set of edges that surround the shape. These edges may move inward or outward compared to the desired position. When the ratio of the circumference to the area is quite large, the entire circumference is moved inward by a certain distance, and if it is 1 nm, the area of the closed area is reduced to be smaller than the area of the circumference. Since the total area is the total energy and the total energy is quite important for each shape, it is necessary for each shape to have a smaller perimeter area ratio. Among the geometric shapes, a circle has a minimum circumference for a unit area of any shape. Thus, a circular or circular pattern will have a smaller MEEF than any non-circular pattern. An approximate circle will have a near-optimal MEEF.

Figure 2 shows how contacts or vias can be created on a germanium wafer by the present invention. An optical lithography machine 200 includes an illumination source 202 that emits optical radiation onto a reticle 204 that includes a plurality of circular aperture patterns 206. Optical radiation is transmitted through the aperture pattern 206 and through one or more lenses 208 to form a pattern 210 on a surface 212 such as a semiconductor wafer. Due to the circumferential rule described above, the use of a circular or approximately circular aperture 206 on the reticle 204 produces a lower (better) MEEF than the use of the square aperture 106 in the reticle 104 of FIG.

Today's reticle fabrication is accomplished by a laser-based reticle writer or a charged particle beam reticle writer such as an electronic mask writer. Today's state-of-the-art technology nodes for tiny characters with a half-pitch of less than 80 nanometers use an electron beam shield using a variable shape beam (VSB) technique with a high voltage electron gun (50 KeV or higher). The cover writer is completed. Conventional reticle or mask writing includes the steps of shredding all desired mask shapes into a component rectangle and a 45 degree triangle of a certain size (eg, a width between 1 nm and 1000 nm) The triangles are such that the combination of all shapes becomes the original shape, perhaps with errors within a certain minimum threshold, and the shapes of the components do not overlap. The shredded shapes are individually written by VSB illumination by an electron beam mask writer. The reticle writing typically involves multiple processes whereby the particular shape is overwritten and overwritten on the reticle. Typically, a reticle is written using two or four passes to evenly eliminate the error so that a more accurate reticle can be produced. Conventionally, the shape of the ingredients does not overlap in a single pass. In fact, since the electron beam mask writer is not completely accurate, some of the VSB illuminations designed to be in close proximity will overlap slightly. In addition, fine gaps are created between certain VSB illuminations designed to be in close proximity. The displacement accuracy of the electron beam mask writer and the semiconductor design have been carefully adjusted to avoid problems due to these overlaps and gaps. For minor errors of 1 nm or less, these problems are particularly slight because the propagating electron beam has a natural blur radius (about 20 to 30 nm in size), making it more than the description of the shapes. The edge produces a Gaussian distribution of the transferred energy. The dose for each VSB exposure is specified in a later and separate step. These doses set the shutter speed or the amount of time that electrons travel to the surface. Proximity effect correction and other correction methods dictate which dose should be applied to each of the VSB illuminations in order to bring the resulting mask shape as close as possible to the original desired mask shape.

Conventionally, a VSB illumination is required for forming a square contact or via pattern. Forming a circular pattern on a reticle using conventional mask writing techniques requires multiple VSB illuminations. Increasing the number of exposures of the VSB has a direct impact on the time required to write the reticle, thus directly transferring to the cost of the reticle. Since it is necessary to form a million contacts and vias for a typical integrated circuit design, it is not practical to use a conventional VSB to illuminate a reticle to form a circular contact or via pattern.

Figure 7 shows an example of how a tiny circular pattern 700 can be formed on a surface such as a reticle by multiple overlapping VSB illuminations by the present disclosure. In Fig. 7, three VSB illumination-rectangular illuminations 702, rectangular illuminations 704, and square illuminations 706 are shown. The use of overlapping illumination allows us to illuminate the write pattern with a VSB illumination that requires fewer VSB shots than is customary. This overlapping illumination technique is particularly effective for small circles of the diameter of the charged particle beam produced by charged particles forward scatter, Coulomb effects, and other physical, chemical, and electromagnetic effects. As shown in FIG. 7, the combination of illumination 702, illumination 704, and illumination 706 three times of VSB illumination is not equal to the target circular pattern 700. The doses for each exposure are shown as part of the "normal" VSB dose: Irradiation 702 and Irradiation 704 have a dose that is 0.7 times the normal dose, and Irradiation 706 has a dose that is 0.6 times the normal dose. As shown, the total dose from all of the illumination 710 in the middle of the circle 700 is therefore 2.0 times the normal dose. Some mask manufacturing procedures have a maximum dose limit, such as 2.0 or twice the normal dose. To compensate for below the normal exposure dose, the VSB illumination boundary of illuminations 702, 704, and 706 extends beyond the boundary of the target circle 700. A charged particle beam simulation can be utilized to calculate a pattern to be formed on the surface to verify that the resulting pattern is within a desired tolerance of the target circular pattern 700.

Figure 8 shows an example of how a tiny circular pattern 802 can be formed on a surface such as a reticle by multiple non-overlapping VSB illuminations by the present disclosure. Five shots are used in this example: illumination 804, illumination 806, illumination 808, illumination 810, and illumination 812. As shown, the combination of illuminations 804, 806, 808, 810, and 812 is different than target pattern 802. The use of five shots to fill the pattern still exhibits a reduction in the number of shots compared to conventional methods, wherein the lines of illumination produce boundaries that make them as close as possible to the target circular pattern. In the example of Fig. 8, the illumination boundaries do not extend as much as the boundary of the target circular pattern as in the example of Fig. 7, because the dose of the individual VSB illumination of Fig. 8 can be made higher than that of Fig. 7. The dose of VSB exposure does not care to exceed a maximum dose limit because the VSB illumination in Figure 8 does not overlap. As in the example of Figure 7, a charged particle beam simulation can be used to calculate the shape to be formed on the surface to verify that the resulting pattern is within a desired tolerance of the target circular pattern 802.

Figure 3 shows a charged particle beam writer 300 with character projection (CP) capabilities. As shown, a particle or electron beam source 302 provides a particle or electron beam 304 to a first mask 308 that can be formed into a rectangular shape by a first aperture 306 formed in the first mask 308. 310. The rectangular beam 310 is then directed to a second mask or template 312 and passed through a second aperture or character 314 formed in the template 312. The charged particle beam 310 is directed through a portion of the character 314 to the surface 326 where a pattern 324 of the shape of the character 314 is formed. In this exemplary embodiment of FIG. 3, template 312 also includes three circular characters of different sizes: character 316, character 318, and character 320. The template 312 also includes a rectangular aperture 322 for VSB illumination that enables the same pattern 312 to be used to generate VSB and CP illumination. Existing commercially available CP charged particle beam systems can be used to form patterns directly on substrates such as germanium wafers, but are not suitable for writing reticle to create a reticle. Even if the character projection (CP) capability can be applied to a charged particle beam writer for a reticle, the conventional mask writing method and system can only be based on the size of a circular CP character located on the template, such as a template. The size of the character 316, the character 318, and the character 320 on 312 is written into a pre-designed circular diameter. Using conventional methods, the number of alternative sizes will be limited by the number of characters that can be placed on the same board.

Figures 5A and 5B show an example of how a single-shot CP character can be used to form a circular shape of different diameters on a surface by varying the dose of radiation. Figure 5A shows a nominal circular pattern 500 that can be formed on a surface using a CP charged particle beam writer such as shown in Figure 3, using a circular CP character such as one of the characters 318. A line segment 502 divides the circular pattern 500 into two parts. Figure 5B shows the dose distribution through pattern 500 along line 502. The horizontal axis corresponds to the straight portion along line segment 502 and the vertical axis shows the dose. Three dose distributions are shown in the drawings: dose distribution for illumination dose 504, illumination dose 506, and illumination dose 508. Each illumination dose curve shows a Gaussian distribution of the charged particle beam. Figure 5B also shows a photoresist threshold intensity 520 which is a dose strength above which the pattern will align on the surface. As shown, the maximum illumination dose 504 will be aligned to one of the dimensions 510, the intermediate illumination dose 506 will be aligned to one of the intermediate dimensions 512, and the lowest illumination dose 508 will be aligned to one of the minimum dimensions 514. Since the pattern is circular, the difference in size is a difference in diameter. Therefore, it is possible to form circular circles of different diameters on the surface by using a single CP character by changing the irradiation dose.

Figure 4 shows an exemplary embodiment of a CP template containing a plurality of circular CP characters of different sizes. Template 402 contains five different sized CP characters: character 404, character 406, character 408, character 410, and character 412. In addition, template 402 includes a rectangular aperture 414 for VSB illumination and a set of triangular apertures 416 for VSB illumination. In one embodiment of the invention, the template 402 can include no triangular apertures 416, but can include only rectangular and circular apertures. Each of the circular CP characters 404, 406, 408, 410, and 412 can form a circular pattern of a range of diameters on a surface by varying the amount of illumination as previously described. By appropriately selecting the size of the circular CP characters during the design of the template, it is possible to form a circular pattern having a wide range of sizes on one surface. Figure 6 shows a flow chart showing an example of how to form a circle of a large size range on a surface using a group of five appropriately sized circular CP characters. In the example of Figure 6, the CP character "A" is capable of forming a circular pattern of size range 602. The CP character "B" is capable of forming a circular pattern of size range 604. The CP character "C" is capable of forming a circular pattern of size range 606. The CP character "D" is capable of forming a circular pattern of size range 608. The CP character "E" is capable of forming a circular pattern of size range 610. As shown, the size range 602 overlaps the size range 604, the size range 604 overlaps the size range 606, the size range 606 overlaps the size range 608, and the size range 608 overlaps the size range 610. Thus, a circular pattern of any size in the full range 620 can be formed using only five CP characters. The diameter range is not strictly limited and must be overlapped to any sufficient degree. It is only necessary to have the largest circular shape that can be formed by a circular CP character at least the same as the smallest circular shape that can be formed by using the next larger circular CP character. Big enough. In other embodiments, the range of possible diameters need not be a continuous range. The available circular pattern size that can be formed on the template 402 using characters can be a plurality of discrete size ranges.

It is known that a two-dimensional dose pattern formed by a single charged particle beam irradiation or a combination of irradiation of charged particle beams on a surface is called a pattern. Each pattern may be associated with its location and the exposure dose information used to include the respective charged particle beam illumination of the pattern. A pattern library can be pre-computed and enabled to have shred or mask data preparation functions. The pattern can also be parameterized. Figure 9 shows an example of a circle on a surface that represents a set of patterns that can be formed by a parametric pattern. The parameter of pattern 902 is its diameter "d", where "d" can be any value between 50 and 100 units. In one embodiment, the pattern can be calculated using a set of circular CP characters using a variable shaped illumination dose that is capable of producing any dose map representing a circular pattern in the size range of 50 to 100 units.

It should be noted that as is common in semiconductor design, a two-dimensional shape, such as a circle, represents a shape that is viewed from the top down on the semiconductor wafer. In the case of joints and through holes, the actual three-dimensional manufacturing shape may be cylindrical or approximately cylindrical.

The method of using VSB illumination or circular CP characters for forming a circle on a surface such as a reticle can also be used to form a pattern directly on a wafer such as a germanium wafer using a maskless direct writing method. It should be noted that for direct writes, MEEF does not matter.

The technique of the present disclosure can also be used when the desired pattern to be formed on a surface is approximately circular. Figure 11A shows an approximate circular pattern 1102 that can be used as a desired mask pattern for a joint or channel. The pattern 1102 can be a desired compromise between the conductive material in the layer such as the MEEF and the layer on the contact or via and the maximum contact area between the conductive materials in the layer below the contact or via. Figure 11B shows an illumination group 1104 of five VSB illuminations in which the alignment pattern on a surface can be brought close to the desired pattern 1102 at an appropriate dose in the non-overlapping VSB illumination example. The illumination group 1104 includes an illumination 1110, an illumination 1112, an illumination 1114, an illumination 1116, and an illumination 1118, which are rectangular illuminations of different widths and heights in the exemplary embodiment. The doses of the illuminations in the illumination group can be varied relative to each other. The pattern aligned on the photoresist applied to the surface is shaped 1120 to the same extent as shape 1102 within a predetermined tolerance. This example shows how an approximately circular pattern can be formed using the techniques of the present disclosure.

Forming a circle on a surface can be approximated by a non-circular shape such as a polygon. When a circle needs to be formed on a surface such as a wafer or a substrate, the result may be an approximately circular shape, such as a curve shape that closely approximates a circle.

10 is a schematic flow diagram 1000 of an embodiment of the present disclosure for using optical lithography to prepare a surface for fabricating a substrate such as an integrated circuit on a germanium wafer. . The input data for this procedure is a set of desired patterns 1002 to be formed on a reticle. The set of desired patterns 1002 can include a desired set of circular patterns that are received by an input device. Step 1004 is a mask data preparation (MDP) step. The MDP step 1004 can include a shredding operation in which the illumination overlap is allowed or not allowed, and wherein a different dose specification manner is allowed. The shred can include setting a set of VSB illuminations, or can include using a CP template information 1006 to set a CP character and an exposure dose, or can include setting a combination of VSB and CP illumination. The MDP step 1004 can also include selecting one or more patterns from a pattern library 1008 to conform to a desired pattern. The selected pattern can include a parametric pattern. The MDP step 1004 can also include an operation for determining an optimization method (VSB illumination, a CP illumination, or a pattern) for each desired pattern. The optimization criteria can be, for example, to minimize the number of shots or the charged particle beam system write time. The MDP step 1004 can also include using a particle beam simulation to calculate a pattern to be formed on the surface by a set of illumination, and can also include if the calculated pattern differs from the desired pattern by a predetermined tolerance. Update the illumination group and recalculate the pattern. Particle beam simulation can include forward scatter, photoresist diffusion, coulomb effect, back scatter, load, blur, and etch simulation of any of these simulations, as well as the use of charged particle beam systems and program information 1010. The MDP step 1004 outputs a predetermined illumination list 1012 containing a combined list of VSB and CP illumination and illumination from the template to an output device. The illumination in the illumination list 1012 includes dose information. In step 1014, proximity effect correction (PEC) and/or other corrections can be performed, or improved by an earlier estimated correction. Step 1014 uses illumination list 1012 as an input and generates a determined illumination list 1016 in which the illumination dose is adjusted. The determined illumination list 1016 is used by the charged particle beam system 1018 to expose the photoresist previously coated on the reticle to form a set of patterns 1020 on the photoresist. After a variety of different steps 1022, the reticle is transformed into a reticle 1024. A reticle 1024 is used in an optical lithography machine 1026 to transfer a desired set of patterns, such as a circular pattern, onto a substrate, such as a wafer, to produce a wafer image 1028 from which to produce 矽Wafer.

A pattern generation step 1030 in Fig. 10 calculates a dose map from a CP character with a particular dose or from a set of VSB illuminations with potentially different doses. Pattern generation step 1030 uses CP template information 1006. The CP template information can include information about a plurality of circular CP characters of different sizes. Pattern generation step 1030 can also include using charged particle beam simulation to calculate the pattern. The particle beam simulation of the pattern can include any of forward scattering, photoresist diffusion, coulombic effects, and etch simulation, and can use a charged particle beam system and program information 1010. Pattern generation step 1030 can also include calculations for a set of patterns to produce a parametric pattern.

The various processes described in the present disclosure can be implemented using a general computer and a suitable computer software as an arithmetic device. Multiple computers or processor cores can be used in parallel because of the large amount of computation required. In an embodiment, for one or more computational frequent steps in the process, the computations can be divided into a plurality of two-dimensional geometric regions to support parallel processing. In another embodiment, a single or multiple dedicated hardware devices can be used to perform one or more steps of calculations at a faster rate than with a typical computer or processor core. The optimization and simulation procedures described in the present disclosure can include a repetitive optimization procedure, such as simulated annealing, or can be constructed from only a constructive, eager, decisive, or other program that does not require rework.

All circles referred to in the context of the present invention are to be interpreted as including also approximately circular. Likewise, all references to circular patterns, circular apertures, circular characters, or circular CP characters should be interpreted to also include approximately circular patterns, apertures, characters, or CP characters. In addition, all references to cylinders are to be construed as including approximately cylinders, and all references to the cylinders should include approximately cylindrical shapes.

Although the specification has been described in detail with reference to the specific embodiments, it will be understood that those skilled in the art are able to immediately understand alternative, alternative, and equivalent forms of the embodiments. These and other modifications of the system and method of the present invention for making a circular pattern on a surface or for making an integrated circuit, or for a method or system for shredding or masking data preparation Variations can be made by those skilled in the art without departing from the spirit and scope of the present invention, which is more specifically set forth in the appended claims. In addition, it will be appreciated by those skilled in the art that the foregoing description is for illustrative purposes only and is not intended to be limiting. Therefore, the subject matter of the present invention is intended to cover such modifications and variations as fall within the scope of the appended claims.

100. . . Optical lithography machine

102. . . Source of illumination

104. . . Mask

106. . . Pore pattern

108. . . lens

110. . . pattern

112. . . surface

200. . . Optical lithography machine

202. . . Source of illumination

204. . . Mask

206. . . Pore pattern

208. . . lens

210. . . pattern

212. . . surface

300. . . Charged particle beam writer

302. . . Particle or electron beam source

304. . . Particle or electron beam

306. . . First pore

308. . . First mask

310. . . Rectangular beam

312. . . Second mask or template

314. . . Second aperture or character

316. . . character

318. . . character

320. . . character

322. . . Rectangular aperture

324. . . pattern

326. . . surface

402. . . Template

404. . . character

406. . . character

408. . . character

410. . . character

412. . . character

414. . . Rectangular aperture

416. . . Triangular pore

500. . . Nominal circular pattern

502. . . Line segment

504. . . Irradiation dose

506. . . Irradiation dose

508. . . Irradiation dose

510. . . size

512. . . Intermediate size

514. . . smallest size

520. . . Photoresist threshold

602. . . Size range

604. . . Size range

606. . . Size range

608. . . Size range

610. . . Size range

620. . . Full size range

700. . . Circular pattern

702. . . Rectangular illumination

704. . . Rectangular illumination

706. . . Square illumination

710. . . intermediate

802. . . Circular pattern

804. . . Irradiation

806. . . Irradiation

808. . . Irradiation

810. . . Irradiation

812. . . Irradiation

1000. . . Summary flow chart

1002. . . Required pattern

1104. . . Mask data preparation step

1006. . . CP template information

1008. . . Pattern library

1010. . . Program information

1012. . . Setting up an irradiation list

1016. . . Determine the exposure list

1018. . . Charged particle beam system

1020. . . pattern

1022. . . step

1024. . . Mask

1026. . . Optical lithography machine

1028. . . Wafer image

1030. . . Pattern generation step

1102. . . Approximate circular pattern

1104. . . Illumination group

1110. . . Irradiation

1112. . . Irradiation

1114. . . Irradiation

1116. . . Irradiation

1118. . . Irradiation

1120. . . shape

Figure 1 shows a conventional method of forming a circular pattern such as a contact or a via on a wafer;

Figure 2 shows a method of forming a circular pattern such as a contact or a via on a wafer by the present invention;

Figure 3 shows a charged particle beam writer with character projection (CP) capability;

Figure 4 shows a character projection template containing one of a plurality of circular characters;

Figure 5A shows a pattern formed by illumination of a circular character projection character;

Figure 5B shows the effect of changing the dose on the size of the pattern aligned on the surface by the projection projection of the character of Figure 5A;

Figure 6 shows a flow chart showing the range of diameters of a circular pattern that can be formed on a surface using a set of circular character projection characters;

Figure 7 shows how overlapping VSB illumination can be utilized to write a circular pattern;

Figure 8 shows how non-overlapping VSB illumination can be utilized to write a circular pattern;

Figure 9 shows that a parametric pattern can be used to create a circular pattern on a surface;

Figure 10 is a conceptual flow diagram showing the fabrication of a reticle and the fabrication of an integrated circuit using an exemplary method of the present invention;

Figure 11A shows a pattern of one of the desired approximate circles;

Figure 11B shows a set of non-overlapping VSB illuminations capable of forming the pattern of Figure 11A.

200. . . Optical lithography machine

202. . . Source of illumination

204. . . Mask

206. . . Pore pattern

208. . . lens

210. . . pattern

212. . . surface

Claims (37)

A method for fabricating a semiconductor device on a substrate, the method comprising: providing a reticle, wherein the reticle comprises a plurality of circular patterns, wherein the reticle is fabricated using a charged particle beam system, wherein The circular patterns on the reticle are fabricated using a plurality of illuminations from a variable shape beam (VSB) of a charged particle beam system, wherein the plurality of illuminations are capable of allowing each other to overlap each other, wherein The combination of the plurality of illuminations is different from the plurality of desired patterns, and wherein the doses of the illumination in the plurality of illuminations are varied relative to each other; and optical lithography is used to utilize the circular patterns in the mask A plurality of circular patterns are formed on the substrate. A method for the preparation of shredded or masked data for use in charged particle beam lithography, the method comprising: inputting a set of patterns to form a plurality of circles on a surface; Irradiating the set of circular patterns, wherein the doses of the illumination in the set of illuminations are changeable relative to each other, wherein each of the illuminations in the set of illuminations is selected from a variable shape beam (VSB) illumination and a character projection (CP) illuminating the group; and outputting the group of illumination including dose information. The method of claim 2, wherein the set of illumination comprises a one-shot projection (CP) character illumination. The method of claim 2, wherein the group of illuminations comprises a plurality of illuminations and the system will utilize a single CP character and by using a different agent A large number of circular patterns of different sizes are formed in quantities. The method of claim 2, wherein the step of determining comprises: setting a plurality of illuminations of the variable shape beam (VSB) for one of the selected patterns of the input set of patterns, and wherein the VSBs The illumination systems are allowed to overlap each other, and wherein the combination of the illumination of the set is different from the selected pattern. The method of claim 2, wherein the step of determining comprises: setting a plurality of illuminations of the non-overlapping VSB for one of the selected patterns of the set of patterns, and wherein the combination of the groups of illuminations is different In the selected pattern. The method of claim 2, wherein the set of illuminations are sequentially used to make a circle on a reticle, and wherein the reticle is later used to fabricate a wafer. cylinder. A method for forming a plurality of circular patterns on a surface, the method comprising: providing a source of charged particle beams; and defining a variable shape beam for each desired circular pattern in the plurality of circular patterns ( a plurality of illuminations of VSB), wherein the illuminations may overlap each other, and wherein the doses of the illuminations may be varied relative to each other, and wherein the combination of the plurality of illuminations is different from the desired circular pattern; The majority of the VSB illuminations form a plurality of circular patterns on the surface. For example, the method of claim 8 of the patent scope further includes: Calculating a calculated pattern on the surface by the plurality of VSB illuminations; if the difference between the calculated pattern and the desired circular pattern exceeds a predetermined tolerance, updating the majority of the VSB illumination and recalculating The calculated pattern. The method of claim 9, wherein the calculating step is performed using a charged particle beam simulation. The method of claim 10, wherein the charged particle beam simulation comprises a group consisting of forward scatter, back scatter, photoresist diffusion, coulomb effect, etching, blurring, loading, and photoresist charging. At least one simulation. For example, the method of claim 8 wherein the majority of the VSB illuminations are set in a constructive or decisive manner without the need for iteration. The method of claim 8, wherein the majority of the VSB illumination systems are non-overlapping during the set of steps of the majority of the VSB illumination. A system for forming a plurality of circular patterns on a surface, the system comprising: a source of charged particle beams; a first mask comprising an aperture illuminable by the source of charged particles to form a shaped beam a same board comprising a plurality of circular character projection (CP) characters of different sizes, the charged particle beam being illuminable through the template; a guiding device guiding the shaped beam to illuminate the template One of the plurality of CP characters; and an arithmetic device, wherein the arithmetic device is capable of setting which dose to use and using a single CP character to form a plurality of circular patterns of different sizes on the surface. The system of claim 14, wherein the template comprises a plurality of circular CP characters, and wherein the sizes of the characters are calculated so that a minimum of the number of variable doses can be formed on the surface. A circular pattern of any size between the CP character and the largest CP character. A system for forming a plurality of circular patterns on a surface, the system comprising: a source of charged particle beams; a plate comprising a plurality of apertures of a variable shape beam (VSB); and an arithmetic device, wherein the operation The device is capable of arranging a circular pattern for one of a plurality of circular patterns to define a plurality of illuminations of a variable shape beam (VSB), wherein the plurality of illuminations can overlap, and wherein the plurality of illuminations are different from the Select a circular pattern. The system of claim 16, wherein the computing device is further capable of: calculating, by the plurality of VSBs, a calculated pattern on the surface; and if the calculated pattern and the desired circle are If the difference in pattern exceeds a predetermined tolerance, then the majority of the VSB illumination is updated and the calculated pattern is recalculated. A system for forming a plurality of circular patterns on a surface, the system comprising: a source of charged particle beams; a plate comprising a plurality of apertures of a variable shape beam (VSB) and a set of character projection (CP) characters Both; a pattern library; and an arithmetic device, wherein the VSB illumination, or one or more CP illuminations, or one or more of the patterns can provide an optimal method of forming the pattern, The arithmetic device is capable of setting each circular pattern on the surface. The system of claim 18, wherein the computing device optimizes the number of shots or the charged particle beam write time. The system of claim 18, wherein the computing device defines a VSB illumination group comprising a plurality of doses for a plurality of patterns defined to be formed by VSB illumination. The system of claim 18, wherein the computing device specifies a number of CP illumination or CP illumination groups for a plurality of patterns that are to be formed by VSB illumination. A method for fabricating a same plate for charged particle beam lithography of character projection (CP) and for forming a plurality of circular or nearly circular patterns of different sizes on a surface, the method comprising The following step: setting a first circular or approximately circular character having a first diameter, wherein the first circular or approximately circular character can be different by using a plurality of patterns formed in a first size range on the surface; a second circular or approximately circular character having a second diameter, the second diameter being greater than the first diameter, Wherein the second circular or approximately circular character is capable of forming a plurality of patterns in a second size range on the surface by using different doses; and wherein the first circular or approximately circular character can be Forming a maximum pattern that is at least as large as a minimum pattern that can be formed by the second circular or approximately circular character; and fabricating a first circular or approximately circular character, and the second circular shape Or a template of approximate circular characters. The method of claim 22, further comprising the step of using the template to form a plurality of circular or approximately circular patterns of different sizes on the surface. A template for charged particle beam lithography for character projection (CP), comprising: a first aperture having a circular or approximately circular shape of a first diameter, wherein the first aperture is capable of changing an irradiation dose And forming, in an illumination, a plurality of patterns in a first size range on a surface; and a second aperture having a second diameter of a circular or approximately circular shape, the second diameter being greater than the first a diameter, wherein the second aperture is capable of forming a plurality of patterns in a second size range on the surface by changing an irradiation dose; Wherein the first size range is continuous with the second size range. A method for shredding or masking data preparation for use in charged particle beam lithography, the method comprising the steps of: inputting a contact or via pattern to be formed on a surface, wherein the contact or pass The pattern of holes comprises a total area, and wherein the pattern of contacts or vias is represented as a square or approximately square; and a set of illumination is provided for a charged particle beam writer for a shaped beam, wherein the set of illumination can be formed A circular or approximately circular pattern is on the surface, and the circular or nearly circular pattern has an area within a predetermined tolerance of the total area. The method of claim 25, wherein the set of illumination comprises a circular or approximately circular character projection illumination. The method of claim 26, wherein a single circular or approximately circular character is projected onto the surface to form the circular or approximately circular pattern on the surface. The method of claim 25, wherein the group of illuminations comprises a plurality of illuminations of a variable shape beam (VSB). The method of claim 28, wherein the pair of illuminations in the plurality of VSB illuminations overlap. The method of claim 25, wherein the step of determining comprises: calculating an area of the circular or approximately circular pattern on the surface. The method of claim 30, wherein the step of calculating comprises charged particle beam simulation. The method of claim 31, wherein the charged particle beam simulation At least one of the group consisting of forward scatter, photoresist diffusion, coulomb effect, back scatter, load, blur, and etch is included. The method of claim 25, wherein each of the illuminations of the set of illuminations comprises a specified dose, and wherein the doses of the two of the set of illuminations are different. A method for fabricating a semiconductor device on a substrate, the method comprising the steps of: inputting a contact or via pattern to be formed on a mask, wherein the contact or via pattern comprises a total area, And wherein the contact or via pattern is represented as a square or approximately square; and a set of illumination for a charged particle beam writer for a shaped beam, wherein the set of illumination forms a circular or approximately circular shape Patterned on the reticle, and the circular or nearly circular pattern has an area within a predetermined tolerance of the total area; using the set of illuminations to form the circle or approximate circle Forming a pattern on the reticle; using optical lithography to form a circular or nearly circular pattern on the substrate using the circular or approximately circular shape on the reticle. The method of claim 34, wherein the set of illumination comprises a circular or approximately circular character projection illumination. A method of claim 35, wherein a single circular or approximately circular character is projected onto the surface to form the circular or approximately circular pattern on the surface. The method of claim 34, wherein the set of illumination comprises a plurality of illuminations of a variable shape beam (VSB), wherein a pair of illuminations in the plurality of VSB illuminations overlap.