Optical Proximity Correction Method, System, Mask, Equipment and Storage Medium

Abstract

An optical proximity correction method and its system, mask, device, and storage medium. The optical proximity correction method includes: providing a graphic area including a plurality of main graphics; obtaining the setting rules for auxiliary graphics; setting first auxiliary graphics around the main graphics based on the setting rules; the setting rules include the first line-end distance between the auxiliary graphics and the main graphics and the second line-end distance between adjacent auxiliary graphics, the first spacing between the auxiliary graphics and the main graphics, and the second spacing between adjacent auxiliary graphics; based on the first line-end distance, the second line-end distance, the first spacing, and the second spacing, expanding the edges of the main graphics and the first auxiliary graphics to obtain a setting prohibited area, and the remaining area is used as a setting permitted area; performing a setting rule check on the setting permitted area; when the setting permitted area meets the setting rules, setting second auxiliary graphics in the setting permitted area. The embodiments of the present invention improve the accuracy and effect of optical proximity correction.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of semiconductor manufacturing, and in particular, to an optical proximity correction method and system, a mask, a device, and a storage medium. Background Art

[0002] Lithography technology is a crucial technology in semiconductor manufacturing. Lithography technology can transfer the pattern from the mask to the surface of the silicon wafer to form a semiconductor product that meets the design requirements. The lithography process includes an exposure step and a development step that follows the exposure step. In the exposure step, light passes through the light-transmitting area of the mask and irradiates the silicon wafer coated with photoresist. The photoresist undergoes a chemical reaction under the irradiation of light. In the development step, the lithography pattern is formed by taking advantage of the different dissolution degrees of the photosensitive and non-photosensitive photoresists in the developer, realizing the transfer of the mask pattern to the photoresist. After the lithography process, an etching step is usually also included. That is to say, the silicon wafer is etched based on the lithography pattern formed on the photoresist layer to further transfer the pattern of the mask to the silicon wafer.

[0003] In semiconductor manufacturing, as the design size continues to shrink, the design size gets closer and closer to the limit of the lithography imaging system, and the diffraction effect of light becomes more and more obvious, resulting in the degradation of the optical image of the design pattern. The actually formed lithography pattern is severely distorted relative to the pattern on the mask, and finally the actual pattern formed on the silicon wafer through lithography is different from the design pattern. This phenomenon is called the Optical Proximity Effect (OPE). Technical means such as Sub-Resolution Assist Features (SRAF), Optical Proximity Correction (OPC), Inverse Lithography Technology (ILT), Double Patterning (DP), and Self-aligned Double Patterning (SADP) are all used to improve the lithography resolution.

[0004] A scattering bar is a type of sub-resolution assist feature. By setting an assist feature bar around the main feature, the lithography quality of the main feature can be improved. Among them, the main feature is an exposable pattern, while the scattering bar is usually a non-exposable pattern. However, the current effect of optical proximity correction still needs to be improved. Summary of the Invention

[0005] The problem solved by the embodiments of the present invention is to provide an optical proximity correction method, its system, a mask, a device, and a storage medium, which are beneficial to improving the accuracy and effect of optical proximity correction and increasing the lithography process window.

[0006] To solve the above problems, the embodiments of the present invention provide an optical proximity correction method, including: providing a graphic area including a plurality of main graphics, the extension direction of the main graphics being horizontal, and the direction perpendicular to the horizontal being vertical; obtaining a setting rule for setting auxiliary graphics around the main graphics; based on the setting rule, setting first auxiliary graphics around the main graphics; the setting rule including: a first line-end distance between the auxiliary graphics and the main graphics along the horizontal direction, and a second line-end distance between adjacent auxiliary graphics, a first spacing between the auxiliary graphics and the main graphics along the vertical direction, and a second spacing between adjacent auxiliary graphics; based on the first line-end distance, the second line-end distance, the first spacing, and the second spacing, expanding the edges of the main graphics and the first auxiliary graphics to obtain a setting prohibited area, and the remaining area is used as a setting permitted area; performing a setting rule check on the setting permitted area; when the setting permitted area meets the setting rule, setting second auxiliary graphics in the setting permitted area.

[0007] Correspondingly, the embodiments of the present invention further provide an optical proximity correction system, including: a providing unit for providing a graphic area including a plurality of main graphics, the extension direction of the main graphics being horizontal, and the direction perpendicular to the horizontal being vertical; a rule obtaining unit for obtaining a setting rule for setting auxiliary graphics around the main graphics; an initial setting unit for setting first auxiliary graphics around the main graphics based on the setting rule; a permitted area obtaining unit, the setting rule including a first line-end distance between the auxiliary graphics and the main graphics along the horizontal direction and a second line-end distance between adjacent auxiliary graphics, a first spacing between the auxiliary graphics and the main graphics along the vertical direction and a second spacing between adjacent auxiliary graphics, the permitted area obtaining unit being used to expand the edges of the main graphics and the first auxiliary graphics based on the first line-end distance, the second line-end distance, the first spacing, and the second spacing to obtain a setting prohibited area, and the remaining area is used as a setting permitted area; a rule checking unit for performing a setting rule check on the setting permitted area; a configuration unit for setting second auxiliary graphics in the setting permitted area when the setting permitted area meets the setting rule.

[0008] Correspondingly, the embodiments of the present invention further provide a mask including a plurality of main graphics and auxiliary graphics located around the main graphics, and the auxiliary graphics are set by the optical proximity correction method provided by the embodiments of the present invention.

[0009] Correspondingly, an embodiment of the present invention further provides a device, including at least one memory and at least one processor, where the memory stores one or more computer instructions, and the one or more computer instructions are executed by the processor to implement the optical proximity correction method provided by the embodiment of the present invention.

[0010] Correspondingly, an embodiment of the present invention further provides a storage medium, where the storage medium stores one or more computer instructions, and the one or more computer instructions are used to implement the optical proximity correction method provided by the embodiment of the present invention.

[0011] Compared with the prior art, the technical solution of the embodiment of the present invention has the following advantages:

[0012] In the optical proximity correction method provided by the embodiment of the present invention, first, based on the setting rules of the auxiliary pattern, a first auxiliary pattern is set around the main pattern. Subsequently, based on the first line end distance, the second line end distance, the first spacing, and the second spacing corresponding to the setting rules of the auxiliary pattern, the edges of the main pattern and the first auxiliary pattern are extended to obtain a prohibited setting area, and the remaining area is used as a permitted setting area. The permitted setting area is accordingly an area where it is impossible to successfully add an auxiliary pattern based on the setting rules. After that, a setting rule check is performed on the permitted setting area. When the permitted setting area meets the setting rules, a second auxiliary pattern is set in the permitted setting area, thereby being able to provide an effective optical proximity correction solution for areas where it is impossible to set an auxiliary pattern based on the rules (for example: some complex graphic areas), and further being beneficial to improving the accuracy and effect of optical proximity correction; moreover, compared with the traditional method, the optical proximity correction method provided by the embodiment of the present invention has fewer changed steps and less additional CPU resources consumed, which is beneficial to cost saving and operation speed improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 and Figure 2 shows a schematic diagram of a main pattern and auxiliary patterns arranged around the main pattern;

[0014] Figure 3 is a flowchart of an embodiment of the optical proximity correction method provided by the present invention;

[0015] Figure 4 is a schematic diagram of an embodiment of a graphic area provided by the present invention;

[0016] Figure 5 is in Figure 4 a schematic diagram of setting a first auxiliary pattern around the main pattern shown;

[0017] Figure 6 is based on Figure 5Schematic diagrams of the set prohibited areas and set permitted areas obtained from the main figure and auxiliary figure shown;

[0018] Figure 7 is Figure 3 a flowchart of an embodiment of step S5 in

[0019] Figure 8 is Figure 7 a flowchart of an embodiment of step S51 in

[0020] Figure 9 is Figure 6 a schematic diagram of the first polygon area corresponding to the first set permitted area shown;

[0021] Figure 10 is Figure 9 a schematic diagram of the regular polygon corresponding to the first polygon area shown;

[0022] Figure 11 is Figure 6 a schematic diagram of the second polygon area corresponding to the second set permitted area shown;

[0023] Figure 12 is Figure 11 a schematic diagram of the regular polygon corresponding to the second polygon area shown;

[0024] Figure 13 is an embodiment of the present invention in Figure 5 a schematic diagram of an embodiment of setting a second auxiliary figure around the main figure shown;

[0025] Figure 14 is a functional block diagram of an embodiment of the optical proximity correction system provided by the present invention;

[0026] Figure 15 is Figure 14 a functional block diagram of an embodiment of the rule checking unit in

[0027] Figure 16 is Figure 15 a functional block diagram of an embodiment of the regular polygon obtaining module in

[0028] Figure 17 is a hardware structure diagram of an embodiment of the device provided by the present invention. Detailed implementation manners

[0029] As can be seen from the background art, the current effect of optical proximity correction still needs to be improved. Specifically, one current optical proximity correction method is a model-based assist feature setting method. The model-based setting method simulates the actual exposure result according to the size and inserted position of the assist feature, and then continuously adjusts these parameters to make the main pattern reach the best focus plane and the maximum depth of focus. Or, based on past experience and the data information of the main pattern on the wafer, the assist feature is directly set on the mask.

[0030] However, the model-based assist feature setting method takes too much time, and the requirements for the OPC model are relatively strict. Therefore, this method is less used in actual operation.

[0031] Another optical proximity correction method is a rules-based sub-resolution assist feature (Rules-based SRAF) setting method. This method sets the assist feature around the main pattern based on rules, that is, artificially presets the configuration rules according to experience, and combines information such as the feature size and pitch of the main pattern to adjust parameters such as the line width of the assist feature and the distance between the assist feature and the main pattern. Compared with the model-based setting method, the rules-based setting method requires less time and has a faster operation speed.

[0032] However, the rules-based assist feature setting method requires a large amount of empirical data to establish a rule library. Due to the complexity of the actual mask pattern, limited rules are difficult to cover all cases, especially some complex graphic areas. As a result, some complex graphic areas cannot obtain effective correction solutions, and the assist feature cannot be successfully set, affecting the effect and accuracy of optical proximity correction.

[0033] Figure 1 and Figure 2 shows a schematic diagram of the main pattern MP (Main Pattern) and the assist feature SRAF set around the main pattern MP. Hereinafter, with reference to the accompanying drawings, a rules-based assist feature setting method is taken as an example to explain the reasons why the assist feature cannot be successfully set. The extending direction of the main pattern MP is horizontal (as shown by the x direction in Figure 1 and Figure 2 ), and the direction perpendicular to the horizontal direction is vertical (as shown by the y direction in Figure 1 and Figure 2 ).

[0034] Specifically, when setting the assist feature SRAF, two conditions (A) and (B) need to be satisfied simultaneously to successfully set the assist feature SRAF:

[0035] (A) Layout design conditions: b ≥ CD ≥ a; d ≥ SPACE ≥ c;

[0036] (B) Conditions for SRAF: f ≥ LENGTH ≥ e; h ≥ WIDTH ≥ g; LE2MPLE ≥ i; LE2LE ≥ j; EDGE2MP ≥ k; EDGE2EDGE ≥ l.

[0037] Among them, CD represents the critical dimension of the main pattern MP, SPACE represents the spacing between adjacent main patterns MP along the longitudinal direction; LENGTH refers to the length of the auxiliary pattern SRAF; WIDTH refers to the line width of the auxiliary pattern SRAF; LE2MPLE refers to the distance between the line end of the auxiliary pattern SRAF and the line end of the main pattern MP; LE2LE refers to the distance between adjacent line ends of the auxiliary pattern SRAF; EDGE2MP refers to the distance between the edge of the auxiliary pattern SRAF and the edge of the main pattern MP along the longitudinal direction; EDGE2EDGE refers to the distance between the edges of adjacent auxiliary patterns SRAF along the longitudinal direction.

[0038] In actual situations, when the pattern of the main pattern MP is relatively complex, according to the above conditions, it is difficult to successfully set the auxiliary pattern SRAF at the preset position (for example: Figure 1 and Figure 2 the position shown by the dashed box in), resulting in poor optical proximity correction effect.

[0039] To solve the above technical problems, in the optical proximity correction method provided by the embodiments of the present invention, first, based on the setting rules of the auxiliary pattern, a first auxiliary pattern is set around the main pattern. Subsequently, based on the first line end distance, the second line end distance, the first spacing, and the second spacing, the edges of the main pattern and the first auxiliary pattern are expanded to obtain a setting prohibited area, and the remaining area is used as a setting permitted area. The setting permitted area is correspondingly an area where it is impossible to successfully add an auxiliary pattern based on the setting rules. Then, a setting rule check is performed on the setting permitted area; when the setting permitted area meets the setting rules, a second auxiliary pattern is set in the setting permitted area, so as to provide an effective optical proximity correction solution for areas where it is impossible to set an auxiliary pattern based on the rules (for example: some complex graphic areas), thereby being beneficial to improving the accuracy and effect of optical proximity correction; moreover, compared with the traditional method, the optical proximity correction method provided by the embodiments of the present invention has fewer change steps and less additional CPU resources consumed, which is beneficial to cost savings and improving the operation speed.

[0040] Figure 3 It is a flowchart of an embodiment of the optical proximity correction method of the present invention. As an example, the optical proximity correction method described in this embodiment includes the following basic steps:

[0041] Step S1: Provide a graphic area including a plurality of main graphics, the extension direction of the main graphics being horizontal, and the direction perpendicular to the horizontal being vertical;

[0042] Step S2: Obtain the setting rules for setting auxiliary graphics around the main graphics;

[0043] Step S3: Based on the setting rules, set first auxiliary graphics around the main graphics;

[0044] The setting rules include: the first line-end distance between the auxiliary graphics and the main graphics along the horizontal direction, and the second line-end distance between adjacent auxiliary graphics, the first spacing between the auxiliary graphics and the main graphics along the vertical direction, and the second spacing between adjacent auxiliary graphics; based on the first line-end distance, the second line-end distance, the first spacing, and the second spacing, expand the edges of the main graphics and the first auxiliary graphics to obtain a setting prohibited area, and the remaining area is used as a setting permitted area;

[0045] Step S5: Check the setting rules for the setting permitted area;

[0046] Step S6: When the setting permitted area meets the setting rules, set second auxiliary graphics in the setting permitted area.

[0047] To make the above objects, features, and advantages of the embodiments of the present invention more obvious and understandable, the following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings.

[0048] Combined with Figure 4 , Figure 4 is a schematic diagram of the graphic area provided in this embodiment. Execute Step S1 to provide a graphic area 100 including a plurality of main graphics 10. The extension direction of the main graphics 10 is horizontal (as shown by the X direction in Figure 4 ), and the direction perpendicular to the horizontal is vertical (as shown by the Y direction in Figure 4 ).

[0049] The graphic area 100 is used to fabricate a mask plate used in the lithography process of a chip. Using the mask plate as a mask, the photoresist on the wafer can be exposed to form a photoresist pattern in each chip area on the wafer. The photoresist pattern can be used to etch the chip area of the wafer, thereby forming device structures such as trenches, gates, metal lines, or conductive plugs in the chip area of the wafer.

[0050] The main pattern 10 is the target pattern expected to be formed on the wafer. The main pattern 10 is an exposable pattern, the size of the main pattern 10 is larger than the resolution critical value of the lithography process, and the main pattern 10 is used to define the photoresist pattern formed by exposure. In this embodiment, the main pattern 10 is a rectangular pattern. In this embodiment, the main pattern 10 is used to define the pattern of the metal line (Metal Layer).

[0051] With reference to Figure 3 , step S2 is performed to obtain the setting rules for setting the auxiliary pattern around the main pattern 10. The setting rules for setting the auxiliary pattern around the main pattern 10 are obtained to facilitate the setting of the first auxiliary pattern around the main pattern 10, and subsequently, the edges of the main pattern 10 and the first auxiliary pattern can be extended based on the setting rules.

[0052] In this embodiment, the setting rules include: the first line-end distance between the lateral auxiliary pattern and the main pattern 10, and the second line-end distance between adjacent auxiliary patterns, the first spacing between the longitudinal auxiliary pattern and the main pattern 10, and the second spacing between adjacent auxiliary patterns. In this embodiment, the setting rules further include: the critical dimension of the main pattern 10, the spacing between the main patterns 10 along the longitudinal direction, the length of the auxiliary pattern, the line width and area of the auxiliary pattern. The setting rules can be obtained from the empirical rule library, and the data in the empirical rule library can be obtained based on the integrated circuit process capability (IC process capability) and the mask writing capability (Mask writing capability). Therefore, for different process conditions and mask writing capabilities, the setting rules are correspondingly different.

[0053] As an example, the setting rules include (A) and (B):

[0054] (A) Layout design conditions: b ≥ CD ≥ a; d ≥ SPACE ≥ c;

[0055] (B) Conditions of the auxiliary pattern: f ≥ LENGTH ≥ e; h ≥ WIDTH ≥ g; LE2MPLE ≥ i; LE2LE ≥ j; EDGE2MP ≥ k; EDGE2EDGE ≥ l.

[0056] Wherein, CD represents the critical dimension of the main pattern 10, SPACE represents the spacing between adjacent main patterns 10 along the longitudinal direction; LENGTH refers to the length of the auxiliary pattern; WIDTH refers to the line width of the auxiliary pattern; LE2MPLE refers to the first line-end distance between the transverse auxiliary pattern and the main pattern 10; LE2LE refers to the second line-end distance between adjacent transverse auxiliary patterns; EDGE2MP refers to the first spacing between the longitudinal auxiliary pattern and the main pattern 10; EDGE2EDGE refers to the second spacing between adjacent longitudinal auxiliary patterns.

[0057] Combined with reference Figure 5 , Figure 5 is a schematic diagram of setting the first auxiliary pattern around the main pattern shown in Figure 4 . Perform step S3, and based on the setting rules, set the first auxiliary pattern 11 around the main pattern 10.

[0058] In this embodiment, first use the auxiliary pattern setting method based on empirical rules (Rule-based) to set the first auxiliary pattern 11 around the main pattern 10, so as to be compatible with the existing process, and then based on the main pattern 10 and the first auxiliary pattern 11, identify the areas where the auxiliary pattern cannot be successfully set based on the empirical rules. In this embodiment, the first auxiliary pattern 11 is a scattering bar (Scattering Bar, SB). The scattering bar is a sub-resolution auxiliary pattern (SRAF). Setting the scattering bar around the main pattern 10 is beneficial to improving the light intensity contrast, reducing the edge placement error (Edge Placement Error, EPE), and also beneficial to increasing the depth of focus, thereby improving the lithography process window.

[0059] Combined with reference Figure 6 , Figure 6 is a schematic diagram of the prohibited setting area and the permitted setting area obtained based on the main pattern and the first auxiliary pattern shown in Figure 5 . Perform step S4. The setting rules include: the first line-end distance between the transverse auxiliary pattern and the main pattern 10, and the second line-end distance between adjacent auxiliary patterns, the first spacing between the longitudinal auxiliary pattern and the main pattern 10, and the second spacing between adjacent auxiliary patterns; based on the first line-end distance, the second line-end distance, the first spacing, and the second spacing, expand the edges of the main pattern 10 and the first auxiliary pattern 11 to obtain the prohibited setting area 100F, and the remaining area is used as the permitted setting area 100P.

[0060] In the semiconductor field, setting assist patterns based on empirical rules requires a large amount of empirical data to establish a rule library. Due to the complexity of actual mask patterns, limited rules are difficult to cover all cases, especially in some complex graphic regions, which leads to the lack of effective correction solutions for some complex graphic regions (such as Figure 5 shown by the dashed box), and the assist pattern cannot be successfully set, affecting the effect of optical proximity correction.

[0061] In this embodiment, first, based on the setting rules of the assist pattern, a first assist pattern 11 is set around the main pattern 10. Subsequently, based on the first line end distance, the second line end distance, the first spacing, and the second spacing corresponding to the assist pattern setting rules, the edges of the main pattern 10 and the first assist pattern 11 are extended to obtain a setting prohibited area 100F, and the remaining area is used as a setting permitted area 100P. The setting permitted area 100P is the area where the assist pattern cannot be successfully added based on the setting rules. In this embodiment, the area where the assist pattern cannot be successfully added based on the setting rules is identified accordingly, so as to facilitate subsequent checking of the setting rules for the setting permitted area 100P to determine whether a second assist pattern can be set in the setting permitted area 100P.

[0062] In this embodiment, the first line end distance in the setting rules is at least i, the second line end distance is at least j, the first spacing is at least k, and the second spacing is at least l. Therefore, in this embodiment, as Figure 6 shown, along the horizontal direction, the edge of the main pattern 10 is extended outward by i, and the edge of the first assist pattern 11 is extended outward by j; along the vertical direction, the edge of the main pattern 10 is extended outward by k, and the edge of the first assist pattern 11 is extended outward by l. The area where the main pattern 10 and the first assist pattern 11 are located, as well as the extended area, constitute the setting prohibited area 100F. The first assist pattern 10 has been successfully set in the setting prohibited area 100F. Therefore, the remaining area outside the setting prohibited area 100F is the area where the assist pattern cannot be successfully added based on the setting rules. In this embodiment, the remaining area outside the setting prohibited area 100F is identified as the setting permitted area 100P, so as to facilitate subsequent checking of the setting rules for the setting permitted area 100P to determine whether a second assist pattern can be set in the setting permitted area 100P.

[0063] As an example, two setting permitted areas 100P are obtained: a first setting permitted area 100P1 and a second setting permitted area 100P2.

[0064] It should be noted that in actual process design, the environment around the main pattern 10 may be relatively complex. For example, Figure 6The edge of the main pattern 10 shown is stepped. When expanding the edges of the main pattern 10 and the first auxiliary pattern 11 based on the first line end distance, the second line end distance, the first spacing, and the second spacing, the set permission area 100P obtained around the main pattern 10 with a stepped edge is usually also an irregular shape with curved edges.

[0065] Execute step S5: Check the setting rules for the set permission area 100P.

[0066] By checking the setting rules for the set permission area 100P, it is determined whether the set permission area 100P meets the requirements for setting the auxiliary pattern, so as to facilitate setting the second auxiliary pattern in the set permission area 100P later. In this embodiment, the setting rules also include the line width, length, and area of the auxiliary pattern.

[0067] The following will describe in detail the steps of checking the setting rules for the set permission area 100P in this embodiment with reference to the accompanying drawings. With reference to Figure 7 shows Figure 3 a flowchart of an embodiment of step S5 in

[0068] Execute step S51 to obtain the regular polygon 130 with the largest area in the set permission area 100P. The regular polygon 130 is composed of one or more rectangles. The regular polygon 130 is composed of the splicing of one or more rectangles.

[0069] As can be seen from the foregoing, due to the complexity of the environment around the main pattern 10, when obtaining the set permission area 100P, the set permission area 100P is usually an irregular shape with curved edges. By obtaining the regular polygon 130 with the largest area in the set permission area 100P, a regular polygon 130 with the largest area is obtained in the irregular shape, so as to facilitate checking the setting rules for the regular polygon 130, and then determine whether the set permission area 100P meets the requirements for setting the auxiliary pattern. Moreover, when the set permission area 100P meets the setting rules, the second auxiliary pattern is set in the set permission area 100P later, and the second auxiliary pattern is correspondingly set in the regular polygon 130, which is beneficial to improving the friendliness of the second auxiliary pattern to the mask manufacturing process.

[0070] With reference to Figure 8 shows Figure 7 a flowchart of an embodiment of step S51 in

[0071] As shown in Figure 9 and Figure 11As shown, perform step S511 to regularize the boundary of the set permission area 100P, obtaining a polygonal area 110 with a stepped edge.

[0072] Regularize the boundary of the set permission area 100P to obtain a polygonal area 110 with a stepped edge. That is to say, the edge of the set permission area 100P is regularized into a stepped edge, making the set permission area 100P regularized into a regular figure composed of multiple rectangles spliced together.

[0073] Specifically, the boundary of the set permission area 100P includes curved edges. Therefore, in specific implementation, mainly regularize the curved edges of the set permission area 100P and convert the curved edges into regular stepped edges. In specific implementation, the more the number of steps, the higher the accuracy of regularizing the boundary of the set permission area 100P. Therefore, during the actual regularization process, the number of steps of the polygonal area 110 can be adjusted accordingly according to the actual accuracy requirements and operation speed requirements.

[0074] As an example, as Figure 9 shown, it shows a schematic diagram of the first polygonal area 1101 with a stepped edge obtained after regularizing the first set permission area 100P1; as Figure 11 shown, it shows a schematic diagram of the second polygonal area 1102 with a stepped edge obtained after regularizing the second set permission area 100P2.

[0075] As Figure 9 and Figure 11 shown, perform step S512 to generate one or more seeds 120 in the polygonal area 110 based on the number of long straight edges of the polygonal area 110. The seed 120 is used as the growth point for subsequent rectangle formation. Subsequently, expand the seed 120 to obtain a rectangle corresponding to the seed 120 and located in the polygonal area 110. The seed 120 corresponds to the rectangle.

[0076] As Figure 9 and Figure 11 shown, in this embodiment, two seeds 120 are generated in the polygonal areas 110 corresponding to the first set permission area 100P1 and the second set permission area 100P2.

[0077] In other embodiments, the number of seeds generated in the set permission area can also be other numbers.

[0078] As Figure 10 and Figure 12As shown, step S513 is performed to expand the seed 120 to obtain a rectangle corresponding to the seed 120 and located in the polygon region 110. The rectangles corresponding to one or more seeds form a regular polygon 130.

[0079] As an example, as Figure 10 shown, a first regular polygon 1301 is formed in the first polygon region 1101; as Figure 12 shown, a second regular polygon 1302 is formed in the second polygon region 1102.

[0080] Continue to refer to Figure 8 and perform step S52 to determine whether the regular polygon 130 meets the requirements of the line width, length, and area of the auxiliary pattern.

[0081] Specifically, determine whether the width of the regular polygon 130 is greater than the minimum line width allowed by the setting rule, determine whether the length of the regular polygon 130 is greater than the minimum length allowed by the setting rule, and determine whether the area of the regular polygon 130 is greater than the minimum area allowed by the setting rule, so as to ensure that the second auxiliary pattern set in the setting permission area 100P can be applied to the mask manufacturing process and the lithography process.

[0082] Continue to refer to Figure 3 and perform step S6: When the setting permission area 100P meets the setting rule, set the second auxiliary pattern 12 in the setting permission area 100P.

[0083] In this embodiment, the first auxiliary pattern 11 is first set, and then based on the setting rule, the edges of the main pattern 10 and the first auxiliary pattern 11 are expanded to obtain a setting prohibited area 100F and a setting permission area 100P. The setting permission area 100P is the area where the auxiliary pattern cannot be successfully added based on the setting rule. Accordingly, the area where the auxiliary pattern cannot be successfully added based on the setting rule is identified, and a setting rule check is performed on the setting permission area 100P. When the setting permission area 100P meets the setting rule, the second auxiliary pattern 12 is set in the setting permission area 100P, so as to provide an effective optical proximity correction solution for the area where the auxiliary pattern cannot be set based on the rule (for example: some complex graphic areas), which is conducive to improving the accuracy and effect of optical proximity correction; moreover, compared with the traditional method, the optical proximity correction method provided in this embodiment has fewer change steps and less additional CPU resources consumed, which is conducive to cost saving and operation speed improvement.

[0084] In this embodiment, after the first auxiliary pattern 11 is set, a second auxiliary pattern 12 is also set in the setting permission area 100P, which is beneficial to increasing the number of auxiliary patterns set around the main pattern 10, and correspondingly beneficial to improving the effect of optical proximity correction. For example, it can further improve the light intensity contrast, reduce the edge placement error, and increase the lithography process window. In this embodiment, the second auxiliary pattern 12 is also a scattering bar.

[0085] Specifically, as Figure 13 shown, when the setting permission area 100P meets the setting rules, the step of setting the second auxiliary pattern 12 in the setting permission area 100P includes: setting the second auxiliary pattern 12 in the regular polygon 130.

[0086] Correspondingly, the present invention also provides an optical proximity correction system. Referring to Figure 14 , a functional block diagram of an embodiment of the optical proximity correction system of the present invention is shown.

[0087] In this embodiment, the optical proximity correction system 400 includes: a providing unit 410 for providing a graphic area, the graphic area including a plurality of main patterns, the extending direction of the main patterns being horizontal, and the direction perpendicular to the horizontal being vertical; a rule obtaining unit 420 for obtaining the setting rules for setting auxiliary patterns around the main patterns; an initial setting unit 430 for setting a first auxiliary pattern around the main patterns based on the setting rules; a permission area obtaining unit 440, the setting rules including a first line end distance between the auxiliary pattern and the main pattern along the horizontal direction and a second line end distance between adjacent auxiliary patterns, a first spacing between the auxiliary pattern and the main pattern along the vertical direction and a second spacing between adjacent auxiliary patterns, the permission area obtaining unit being used to expand the edges of the main patterns and the first auxiliary patterns based on the first line end distance, the second line end distance, the first spacing, and the second spacing to obtain a setting prohibited area, and the remaining area being used as a setting permission area; a rule checking unit 450 for checking the setting rules of the setting permission area; and a configuration unit 460 for setting a second auxiliary pattern in the setting permission area when the setting permission area meets the setting rules.

[0088] In the optical proximity correction system 400 provided in this embodiment, the initial setting unit 430 sets a first auxiliary pattern around the main pattern based on the setting rules of the auxiliary pattern. The permission area obtaining unit 440 expands the edges of the main pattern and the first auxiliary pattern based on the first line end distance, the second line end distance, the first spacing, and the second spacing corresponding to the auxiliary pattern setting rules to obtain a set prohibition area, and the remaining area is used as the set permission area. The set permission area is correspondingly an area where the auxiliary pattern cannot be successfully added based on the setting rules. Then, the rule checking unit 450 is used to check the setting rules for the set permission area, and the configuration unit 460 is used to set a second auxiliary pattern in the set permission area when the set permission area meets the setting rules, so as to provide an effective optical proximity correction solution for the area where the auxiliary pattern cannot be set based on the rules (for example: some complex graphic areas), which is beneficial to improving the accuracy and effect of optical proximity correction; moreover, compared with the traditional optical proximity correction system, the optical proximity correction system provided in this embodiment consumes less additional CPU resources, which is beneficial to cost saving and operation speed improvement.

[0089] The graphic area provided by the providing unit 410 is used to fabricate a mask used in the lithography process of the chip. Using the mask as a mask, the photoresist on the wafer can be exposed to form a photoresist pattern for each chip area on the wafer. The photoresist pattern can be used to etch the chip area of the wafer, so as to form device structures such as trenches, gates, metal lines, or conductive plugs in the chip area of the wafer.

[0090] The main pattern is the target pattern expected to be formed on the wafer. The main pattern is an exposable pattern, the size of the main pattern is larger than the resolution critical value of the lithography process, and the main pattern is used to define the photoresist pattern formed by exposure. In this embodiment, the main pattern is a rectangular pattern. In this embodiment, the main pattern is used to define the pattern of the metal line.

[0091] The rule obtaining unit 420 is used to obtain the setting rules for setting the auxiliary pattern around the main pattern, so that the initial setting unit 430 can set the first auxiliary pattern around the main pattern, and the permission area obtaining unit 440 expands the edges of the main pattern and the first auxiliary pattern based on the setting rules.

[0092] In this embodiment, the setting rules include: the first line end distance between the auxiliary pattern along the horizontal direction and the main pattern 10, and the second line end distance between adjacent auxiliary patterns, the first spacing between the auxiliary pattern along the vertical direction and the main pattern, and the second spacing between adjacent auxiliary patterns. In this embodiment, the setting rules further include: the critical dimension of the main pattern, the spacing between the main patterns along the vertical direction, the length of the auxiliary pattern, the line width of the auxiliary pattern, and the area.

[0093] The rule acquisition unit 420 can obtain the setting rules from an empirical rule library, and the data in the empirical rule library can be obtained based on the integrated circuit process capabilities and mask writing capabilities. Therefore, for different process conditions and mask writing capabilities, the setting rules are correspondingly different.

[0094] As an example, the setting rules include (A) and (B):

[0095] (A) Layout design conditions: b ≥ CD ≥ a; d ≥ SPACE ≥ c;

[0096] (B) Conditions for auxiliary patterns: f ≥ LENGTH ≥ e; h ≥ WIDTH ≥ g; LE2MPLE ≥ i; LE2LE ≥ j; EDGE2MP ≥ k; EDGE2EDGE ≥ l.

[0097] Among them, CD represents the critical dimension of the main pattern, SPACE represents the pitch between adjacent main patterns along the longitudinal direction; LENGTH refers to the length of the auxiliary pattern; WIDTH refers to the line width of the auxiliary pattern; LE2MPLE refers to the first line-end distance between the auxiliary pattern and the main pattern along the transverse direction; LE2LE refers to the second line-end distance between adjacent auxiliary patterns along the transverse direction; EDGE2MP refers to the first pitch between the auxiliary pattern and the main pattern along the longitudinal direction; EDGE2EDGE refers to the second pitch between adjacent auxiliary patterns along the longitudinal direction.

[0098] The initial setting unit 430 sets a first auxiliary pattern around the main pattern based on empirical rules (Rule-based), so that the permission area acquisition unit 440 can identify the area where the auxiliary pattern cannot be successfully set based on the main pattern and the first auxiliary pattern.

[0099] In this embodiment, the first auxiliary pattern is a scattering bar (SB). The scattering bar is a sub-resolution auxiliary feature (SRAF). Setting the scattering bar around the main pattern is beneficial to improving the light intensity contrast, reducing the edge placement error (EPE), and is also beneficial to increasing the depth of focus, thereby improving the lithography process window.

[0100] In the semiconductor field, setting auxiliary patterns based on empirical rules requires a large amount of empirical data to establish a rule library. Due to the complexity of the actual mask patterns, limited rules are difficult to cover all cases, especially some complex pattern areas, which may lead to ineffective correction solutions for some complex pattern areas, unable to successfully set the auxiliary patterns, and affecting the effect and accuracy of optical proximity correction.

[0101] In this embodiment, the initial setting unit 430 sets the first auxiliary pattern around the main pattern based on the setting rules of the auxiliary pattern, so that the permission area obtaining unit 440 can expand the edges of the main pattern and the first auxiliary pattern based on the first line end distance, the second line end distance, the first spacing, and the second spacing corresponding to the auxiliary pattern setting rules, to obtain a setting prohibited area, and the remaining area is used as a setting permission area. The setting permission area is accordingly an area where the auxiliary pattern cannot be successfully added based on the setting rules. The permission area obtaining unit 440 in this embodiment accordingly identifies the area where the auxiliary pattern cannot be successfully added based on the setting rules, so as to facilitate the rule checking unit 450 to perform a setting rule check on the setting permission area to determine whether a second auxiliary pattern can be set in the setting permission area.

[0102] In this embodiment, the first line end distance in the setting rules is at least i, the second line end distance is at least j, the first spacing is at least k, and the second spacing is at least l.

[0103] Therefore, in this embodiment, the permission area obtaining unit 440 expands the edge of the main pattern outward by i in the horizontal direction and expands the edge of the first auxiliary pattern outward by j; in the vertical direction, it expands the edge of the main pattern outward by k and expands the edge of the first auxiliary pattern outward by l. The area where the main pattern and the first auxiliary pattern are located, as well as the expanded area, constitute the setting prohibited area. The first auxiliary pattern has been successfully set in the setting prohibited area. Therefore, the remaining area outside the setting prohibited area is an area where the auxiliary pattern cannot be successfully added based on the setting rules. The permission area obtaining unit 440 in this embodiment identifies the remaining area as the setting permission area, so as to facilitate the rule checking unit 450 to perform a setting rule check on the setting permission area to determine whether a second auxiliary pattern can be set in the setting permission area.

[0104] It should be noted that in specific implementation, the environment around the main pattern may be relatively complex. For example, the edge of the main pattern is stepped. When expanding the edges of the main pattern and the first auxiliary pattern based on the first line end distance, the second line end distance, the first spacing, and the second spacing, the setting permission area obtained around the main pattern with a stepped edge is usually also an irregular shape with curved edges.

[0105] The rule checking unit 450 performs a setting rule check on the setting permission area to determine whether the setting permission area meets the requirements for setting the auxiliary pattern, so as to facilitate the configuration unit 460 to set the second auxiliary pattern in the setting permission area. In this embodiment, the setting rules further include the line width, length, and area of the auxiliary pattern.

[0106] With reference to Figure 15 , it shows Figure 14 a functional block diagram of an embodiment of the rule checking unit 450 in

[0107] In this embodiment, the rule checking unit 450 includes: a regular polygon obtaining module 451, configured to obtain the regular polygon with the largest area in the set permission area, where the regular polygon is composed of one or more rectangles. The regular polygon is formed by splicing one or more rectangles.

[0108] As can be seen from the foregoing, due to the complexity of the environment around the main graphic, when obtaining the set permission area, the set permission area is usually an irregular shape with curved edges. The regular polygon obtaining module 451 obtains the regular polygon with the largest area in the set permission area, so as to obtain a regular shape with the largest area in the irregular shape, which is convenient for setting rule checking on the regular polygon, and further determines whether the set permission area meets the requirements for setting the auxiliary graphic. Moreover, when the set permission area meets the setting rules, the configuration unit 460 sets the second auxiliary graphic in the set permission area, and the configuration unit 460 correspondingly sets the second auxiliary graphic in the regular polygon, which is beneficial to improving the friendliness of the second auxiliary graphic to the mask manufacturing process.

[0109] Combined with reference to Figure 16 , shows Figure 15 a functional block diagram of an embodiment of the regular polygon obtaining module 451 in

[0110] The regularization processor 4511 performs regularization processing on the boundary of the set permission area to obtain a polygon area with a stepped edge, that is, the edge of the set permission area is regularized into a stepped edge, so that the set permission area is regularized into a regular graphic composed of multiple rectangles spliced together.

[0111] Specifically, the boundary of the set permission area includes curved edges. Therefore, in specific implementation, the regularization processor 4511 mainly performs regularization processing on the curved edges of the set permission area to convert the curved edges into regularized stepped edges. In specific implementation, the more the number of steps, the higher the accuracy of the regularization processing on the boundary of the set permission area. Therefore, the regularization processor 4511 can adjust the number of steps of the polygon area according to the actual accuracy requirements and operation speed requirements.

[0112] The seed generated by the seed generator 4512 is used as a growth point for the seed expander 4513 to form a rectangle. The seed expander 4513 expands the seed to obtain a rectangle corresponding to the seed and located in the polygonal area. The seed corresponds to the rectangle.

[0113] Rule checking unit 450 further includes a judgment module 452. The setting rules also include the line width, length, and area of the auxiliary pattern. Judgment module 452 is configured to determine whether the regular polygon meets the requirements for line width, length, and area of the auxiliary pattern. Specifically, judgment module 452 is configured to determine whether the width of the regular polygon exceeds the minimum line width permitted by the setting rules, whether the length of the regular polygon exceeds the minimum length permitted by the setting rules, and whether the area of the regular polygon exceeds the minimum area permitted by the setting rules, thereby ensuring that the second auxiliary pattern set in the permitted area set by configuration unit 460 is suitable for use in the mask manufacturing process and the photolithography process.

[0114] In this embodiment, the initial setting unit 420 sets a first auxiliary graphic around the main graphic, and the permitted area acquisition unit 440 obtains the setting prohibited area and the setting permitted area. The setting permitted area corresponds to the area where the auxiliary graphic cannot be successfully added based on the setting rules. In this embodiment, the area where the auxiliary graphic cannot be successfully added based on the setting rules is identified, and then the rule checking unit 450 performs a setting rule check on the setting permitted area. When the setting permitted area meets the setting rules, the configuration unit 460 sets a second auxiliary graphic in the setting permitted area, thereby providing an effective optical proximity correction solution for areas where auxiliary graphics cannot be set based on the rules (for example: some complex graphic areas), which is beneficial to improving the accuracy and effect of optical proximity correction; moreover, the optical proximity correction system provided by this embodiment consumes less additional CPU resources, which is beneficial to saving costs and improving computing speed.

[0115] In this embodiment, not only does the initial placement unit 430 place a first auxiliary pattern, but the configuration unit 460 also places a second auxiliary pattern in the permitted placement area. This increases the number of auxiliary patterns placed around the primary pattern, which in turn improves the effectiveness of optical proximity correction, for example, by further improving light intensity contrast, reducing edge placement errors, and increasing the photolithography process window. In this embodiment, the second auxiliary pattern is a scattering strip.

[0116] Specifically, when the setting permission area satisfies the setting rule, the configuration unit 460 sets the second auxiliary graphic in the regular polygon.

[0117] Correspondingly, an embodiment of the present invention further provides a mask, comprising a plurality of main patterns and auxiliary patterns located around the main patterns, wherein the auxiliary patterns are provided by the optical proximity correction method provided by an embodiment of the present invention.

[0118] As described above, in the optical proximity correction method provided in this embodiment, first, a first auxiliary pattern is set around the main pattern based on the setting rules of the auxiliary pattern. Subsequently, based on the first line end distance, the second line end distance, the first spacing, and the second spacing corresponding to the setting rules of the auxiliary pattern, the edges of the main pattern and the first auxiliary pattern are expanded to obtain a prohibited setting area, and the remaining area is used as a permitted setting area. The permitted setting area is accordingly an area where it is impossible to successfully add an auxiliary pattern based on the setting rules. After that, a setting rule check is performed on the permitted setting area. When the permitted setting area meets the setting rules, a second auxiliary pattern is set in the permitted setting area, thereby being able to provide an effective optical proximity correction solution for areas where it is impossible to set an auxiliary pattern based on the rules (for example, some complex graphic areas), and further being beneficial to improving the accuracy and effect of optical proximity correction. Therefore, the mask provided in the embodiments of the present invention is beneficial to increasing the lithography process window and improving the matching degree between the patterns on the wafer and the mask patterns.

[0119] The main pattern is used to define the pattern of the metal wire. Correspondingly, after performing a lithography process on the wafer using the mask provided in this embodiment, the pattern quality and pattern accuracy of the formed metal wire pattern are high.

[0120] The embodiments of the present invention further provide a device, which can implement the optical proximity correction method provided in the embodiments of the present invention by loading the above graphic design method in the form of a program. An optional hardware structure of the terminal device provided in the embodiments of the present invention can be as Figure 17 shown, including: at least one processor 01, at least one communication interface 02, at least one memory 03, and at least one communication bus 04.

[0121] In this embodiment, the number of the processor 01, the communication interface 02, the memory 03, and the communication bus 04 is at least one, and the processor 01, the communication interface 02, and the memory 03 complete mutual communication through the communication bus 04. The communication interface 02 can be an interface of a communication module for network communication, such as an interface of a GSM module. The processor 01 may be a central processing unit CPU, or a specific integrated circuit (Application Specific Integrated Circuit, ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention. The memory 03 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory, NVM), such as at least one disk memory. Among them, the memory 03 stores one or more computer instructions, and the one or more computer instructions are executed by the processor 01 to implement the access control method provided in the embodiments of the present invention.

[0122] It should be noted that the above-mentioned implementation terminal device may further include other devices (not shown) that may not be essential to the disclosed content of the embodiments of the present invention; since these other devices may not be essential for understanding the disclosed content of the embodiments of the present invention, the embodiments of the present invention will not introduce them one by one.

[0123] Embodiments of the present invention further provide a storage medium storing one or more computer instructions for implementing the optical proximity correction method provided by the embodiments of the present invention.

[0124] As can be seen from the foregoing, the optical proximity correction method provided by this embodiment can provide an effective optical proximity correction solution for regions where auxiliary patterns cannot be set based on rules (for example, some complex pattern regions), thereby facilitating the improvement of the accuracy and effect of optical proximity correction. Moreover, the optical proximity correction method provided by this embodiment consumes less additional CPU resources, which is beneficial to cost savings and improvement of the operation speed.

[0125] Embodiments of the present invention can be implemented by various means such as hardware, firmware, software, or a combination thereof. In the hardware configuration mode, the method according to the exemplary embodiments of the present invention can be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc. In the firmware or software configuration mode, the embodiments of the present invention can be implemented in the form of modules, processes, functions, etc. The software code can be stored in a memory unit and executed by a processor. The memory unit is located inside or outside the processor and can send data to the processor and receive data from the processor via various known means.

[0126] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. An optical proximity correction method, characterized in that, Comprising: Providing a graphic area including a plurality of main graphics, the extension direction of the main graphics being horizontal, and the direction perpendicular to the horizontal being vertical; Obtaining the setting rules for setting auxiliary graphics around the main graphics; Based on the setting rules, setting a first auxiliary graphic around the main graphic; The setting rules include: the first line-end distance between the auxiliary graphic and the main graphic along the horizontal direction, and the second line-end distance between adjacent auxiliary graphics; the first spacing between the auxiliary graphic and the main graphic along the vertical direction, and the second spacing between adjacent auxiliary graphics; the line width, length and area of the auxiliary graphic; Based on the first line-end distance, second line-end distance, first spacing and second spacing, expanding the edges of the main graphic and the first auxiliary graphic to obtain a setting prohibited area, and the remaining area is used as a setting permitted area; Performing a setting rule check on the setting permitted area; the step of performing a setting rule check on the setting permitted area includes: obtaining the regular polygon with the largest area in the setting permitted area, the regular polygon being composed of one or more rectangles; determining whether the regular polygon meets the requirements of the line width, length and area of the auxiliary graphic; When the setting permitted area meets the setting rules, setting a second auxiliary graphic in the setting permitted area.

2. The optical proximity correction method according to claim 1, wherein When the setting permitted area meets the setting rules, the step of setting a second auxiliary graphic in the setting permitted area includes: setting the second auxiliary graphic in the regular polygon.

3. The optical proximity correction method according to claim 2, wherein The step of obtaining the regular polygon with the largest area in the setting permitted area includes: regularizing the boundary of the setting permitted area to obtain a polygon area with a stepped edge; Based on the number of long straight edges of the polygon area, generating one or more seeds in the polygon area; Expanding the seeds to obtain rectangles corresponding to the seeds and located in the polygon area, and the rectangles corresponding to the one or more seeds form the regular polygon.

4. The optical proximity correction method according to claim 1, wherein The first auxiliary graphic and the second auxiliary graphic are scattering bars.

5. An optical proximity correction system, characterized in that, Comprising: A providing unit for providing a graphic area, the graphic area including a plurality of main graphics, the extension direction of the main graphics being horizontal, and the direction perpendicular to the horizontal being vertical; A rule obtaining unit for obtaining the setting rules for setting auxiliary graphics around the main graphics; An initial setting unit for setting a first auxiliary graphic around the main graphic based on the setting rules; A permitted area obtaining unit, the setting rules including the first line-end distance between the auxiliary graphic and the main graphic along the horizontal direction and the second line-end distance between adjacent auxiliary graphics, the first spacing between the auxiliary graphic and the main graphic along the vertical direction and the second spacing between adjacent auxiliary graphics, and the line width, length and area of the auxiliary graphic, the permitted area obtaining unit being used to expand the edges of the main graphic and the first auxiliary graphic based on the first line-end distance, second line-end distance, first spacing and second spacing to obtain a setting prohibited area, and the remaining area is used as a setting permitted area; A rule checking unit for performing a setting rule check on the set permission area; wherein, the rule checking unit includes: a rule polygon obtaining module for obtaining the largest rule polygon in the set permission area, the rule polygon being composed of one or more rectangles; a judgment module for judging whether the rule polygon meets the requirements of the line width, length, and area of the auxiliary figure. A configuration unit for setting a second auxiliary figure in the set permission area when the set permission area meets the setting rules.

6. The optical proximity correction system according to claim 5, wherein The rule polygon obtaining module includes: a regularization processor for regularizing the boundary of the set permission area to obtain a polygon area with a stepped edge. A seed generator for generating one or more seeds in the polygon area based on the number of long straight edges of the polygon area. A seed expander for expanding the seeds to obtain rectangles corresponding to the seeds and located in the polygon area, and the rectangles corresponding to the one or more seeds form the rule polygon.

7. A photomask, characterized in that, Comprising: A plurality of main figures and auxiliary figures located around the main figures, the auxiliary figures being set by the optical proximity correction method according to any one of claims 1-4.

8. The mask according to claim 7, wherein The main figure is used to define a metal wire figure.

9. A device, characterized in that, Comprising at least one memory and at least one processor, the memory storing one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the optical proximity correction method according to any one of claims 1-4.

10. A storage medium, characterized in that, The storage medium stores one or more computer instructions for implementing the optical proximity correction method according to any one of claims 1-4.

Images