Optical proximity correction method and system, mask, equipment and storage medium

Abstract

An optical proximity correction method and system, a mask, a device and a storage medium, the optical proximity correction method comprising: providing a first target pattern of a current layout layer and a second target pattern of a previous layout layer, the projection of the second target pattern in the current layout layer having an overlapping portion with the first target pattern; according to the first target graph and the second target graph, a derived graph is obtained, and the derived graph is located in the virtual layout layer; and performing optical proximity correction processing on the first target graph in combination with the first target graph and the derived graph. According to the invention, more accurate optical proximity correction processing on the first target graph is facilitated, and the correction accuracy of the optical proximity correction method is improved.

Description

Technical Field

[0001] The 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] In the existing technology, semiconductors must go through the photolithography process, which is the process of light exposing the resist through a mask, and the pattern on the mask is transferred to form a resist pattern. If the size of the mask pattern is very small, the size of the mask pattern will be close to the wavelength of the light that forms the resist pattern, thereby generating an optical proximity effect (OPE), and the pattern on the mask will be deformed during the transfer, and the photolithography quality of the adjacent pattern areas on the mask pattern will be increasingly affected by the optical proximity effect.

[0003] The general method to eliminate the optical proximity effect is to use optical proximity correction (OPC), which corrects the correction pattern formed on a specific layer of the semiconductor. Now that critical dimension (CD) has been introduced into semiconductor design, it will limit the depth of focus (DOF) during lithography and begin to affect the lithography process. Summary of the invention

[0004] The problem solved by the embodiments of the present invention is to provide an optical proximity correction method and system, a mask, a device and a storage medium to improve the correction accuracy of the optical proximity correction.

[0005] To solve the above problems, an embodiment of the present invention provides an optical proximity correction method, including: providing a first target graphic of a current layer and a second target graphic of a previous layer, wherein a projection of the second target graphic in the current layer has an overlapping portion with the first target graphic; obtaining a derived graphic according to the first target graphic and the second target graphic, wherein the derived graphic is located in a virtual layer; and performing optical proximity correction processing on the first target graphic in combination with the first target graphic and the derived graphic.

[0006] Optionally, obtaining a derived graphic according to the first target graphic and the second target graphic includes: projecting the second target graphic into the current layer; and obtaining a derived graphic according to the projection graphic of the second target graphic in the current layer and the first target graphic.

[0007] Optionally, the layer of the current layout also includes a boundary graphic located at the boundary of the first target graphic and in contact with the first target graphic; obtaining a derived graphic based on the first target graphic and the second target graphic, further includes: before obtaining the derived graphic based on the projection graphic of the second target graphic in the current layout layer and the first target graphic, enlarging the projection of the second target graphic in the current layout layer according to the size of the boundary graphic, and obtaining the enlarged projection as the projection graphic.

[0008] Optionally, a derived graphic is obtained based on the projection graphic of the second target graphic in the current layer and the first target graphic, including: obtaining the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic as the initial derived graphic; or, splitting the projection graphic of the second target graphic in the current layer into different types of feature parts according to a specific position; obtaining the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic as the initial derived graphic; splitting the initial derived graphic and taking the feature parts of the same type as derived graphics.

[0009] Optionally, the specific position includes multiple ones of an edge extending in a horizontal direction, an edge extending in a vertical direction, a corner, and a top surface.

[0010] Optionally, an AND Boolean operation is used to obtain the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic.

[0011] Optionally, optical proximity correction processing is performed on the first target graphic in combination with the first target graphic and the derived graphic, including: obtaining a simulated exposure graphic and a corresponding corrected graphic corresponding to the first target graphic in combination with the first target graphic and the derived graphic; after optical proximity correction processing is performed on the first target graphic in combination with the first target graphic and the derived graphic, the correction method further includes: judging whether the simulated exposure graphic meets the correction requirements; when the simulated exposure graphic does not meet the correction requirements, returning the corrected graphic as the first target graphic to obtain a derived graphic based on the first target graphic and the second target graphic; when the simulated exposure graphic meets the correction requirements, completing the optical proximity correction processing.

[0012] Optionally, whether the simulated exposure pattern meets the correction requirements is judged by judging whether the edge placement error of the simulated exposure pattern reaches the correction standard. When the edge placement error of the simulated exposure pattern reaches the correction standard, the simulated exposure pattern is judged to meet the correction requirements; when the edge placement error of the simulated exposure pattern does not reach the correction standard, the simulated exposure pattern is judged to not meet the correction requirements.

[0013] Optionally, combining the first target graphic and the derived graphic to obtain a simulated exposure graphic corresponding to the first target graphic includes: obtaining a first spatial image of the first target graphic; obtaining a second spatial image of the derived graphic; superimposing the first spatial image and the second spatial image to obtain a target spatial image; and obtaining a corresponding simulated exposure graphic based on the target spatial image.

[0014] Optionally, an optical model is used to acquire a first aerial image of a first target graphic; an optical model is used to acquire a second aerial image of a derived graphic; and a photoresist model is used to acquire a corresponding simulated exposure graphic according to the target aerial image.

[0015] Optionally, when a layer plate has a first mask plate parameter; obtaining a derived graphic according to the first target graphic and the second target graphic, also includes: setting a second mask plate parameter of a virtual plate layer corresponding to the derived graphic; obtaining a first aerial image of the first target graphic, obtaining a first aerial image according to the first mask plate parameter; obtaining a second aerial image of the derived graphic according to the second mask plate parameter.

[0016] Optionally, the first mask parameter and the second mask parameter both include: one or more of a transmission rate, a mask deviation and an angle cut.

[0017] Optionally, in the second target graphic provided for the front layer, the second target graphic is a gate graphic.

[0018] Correspondingly, an embodiment of the present invention also provides an optical proximity correction system, including: a graphics providing unit, used to provide a first target graphics of a current layer and a second target graphics of a previous layer, the projection of the second target graphics in the current layer having an overlapping portion with the first target graphics; a derived graphics acquisition unit, used to acquire a derived graphics according to the first target graphics and the second target graphics, the derived graphics being located in a virtual layer; an optical proximity correction unit, used to perform optical proximity correction processing on the first target graphics in combination with the first target graphics and the derived graphics.

[0019] Correspondingly, an embodiment of the present invention further provides a mask, including a pattern obtained by using the optical proximity correction method provided by the embodiment of the present invention.

[0020] Correspondingly, an embodiment of the present invention also provides a device, comprising at least one memory and at least one processor, wherein the memory stores one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the optical proximity correction method provided by an embodiment of the present invention.

[0021] Correspondingly, an embodiment of the present invention further provides a storage medium, wherein 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.

[0022] Compared with the prior art, the technical solution of the embodiment of the present invention has the following advantages:

[0023] In the optical proximity correction method provided by the embodiment of the present invention, a first target graphic of a current plate layer and a second target graphic of a previous plate layer are provided, and a projection of the second target graphic in the current plate layer has an overlapping portion with the first target graphic. A derivative graphic is obtained according to the first target graphic and the second target graphic, and the derivative graphic is located in a virtual plate layer. The first target graphic is combined with the derivative graphic to perform optical proximity correction processing on the first target graphic. If the projection of the second target graphic in the current plate layer has an overlapping portion with the first target graphic, the exposure size of the first target graphic will be affected by the second target graphic. Therefore, a derivative graphic is obtained according to the first target graphic and the second target graphic, and the optical proximity correction processing is performed on the first target graphic in combination with the first target graphic and the derivative graphic. The influence of the second target graphic on the first target graphic can be taken into account, which is conducive to more accurate optical proximity correction processing on the first target graphic and improves the correction accuracy of the optical proximity correction method. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart of an embodiment of an optical proximity correction method of the present invention;

[0025] Figures 2 to 10 is a schematic diagram corresponding to each step in an embodiment of an optical proximity correction method of the present invention;

[0026] Fig.11 is a functional block diagram of an embodiment of an optical proximity correction system of the present invention;

[0027] Fig.12 It is a hardware structure diagram of an embodiment of the device provided by the present invention. DETAILED DESCRIPTION

[0028] As is known from the background art, during optical exposure, the three-dimensional structure of the wafer front layer may cause unexpected changes in the resist shape after the layer structure is developed. This problem leads to difficulties in controlling the critical dimension (CD), especially for implanted film layers without hard masks.

[0029] For the injection layer of the fin field effect transistor (FinFET), a relatively high protruding bottom gate (poly) forms the three-dimensional structure of the front layer in the wafer. Then, during the coating process, the bottom anti-reflective coating (BARC) on the poly is not as thick as on the oxide substrate, and cannot suppress reflection or scattering. This can have a huge impact, generally enhancing the light field on the poly, resulting in the optical proximity correction of the pattern not being able to take into account the impact of the three-dimensional structure of the front layer, and the optical proximity correction structure is not accurate.

[0030] In order to solve the technical problem, an embodiment of the present invention provides an optical proximity correction method. Figure 1 , shows a flow chart of an embodiment of the optical proximity correction method of the present invention.

[0031] In this embodiment, the optical proximity correction method includes the following basic steps:

[0032] Step S1: providing a first target graphic of a current layer and a second target graphic of a previous layer, wherein a projection of the second target graphic in the current layer has an overlapping portion with the first target graphic;

[0033] Step S2: acquiring a derived graphic according to the first target graphic and the second target graphic, wherein the derived graphic is located in a virtual version layer;

[0034] Step S3: performing optical proximity correction processing on the first target pattern by combining the first target pattern and the derived pattern.

[0035] In the embodiment of the present invention, if the projection of the second target graphic in the current plate layer has an overlapping portion with the first target graphic, the exposure size of the first target graphic will be affected by the second target graphic. Therefore, a derived graphic is obtained according to the first target graphic and the second target graphic, and an optical proximity correction process is performed on the first target graphic in combination with the first target graphic and the derived graphic. This can take the influence of the second target graphic on the first target graphic into account, which is conducive to more accurate optical proximity correction processing of the first target graphic and improves the correction accuracy of the optical proximity correction method.

[0036] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present invention more obvious and understandable, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] Figures 2 to 10 It is a schematic diagram corresponding to each step in an embodiment of an optical proximity correction method of the present invention.

[0038] refer to Figure 2, execute step S1: provide a first target graphic 100 of the current layer and a second target graphic 200 of the previous layer, and the projection of the second target graphic 200 in the current layer has an overlapping part with the first target graphic 100.

[0039] The first target pattern 100 is a design pattern of the current layer, and is used as a reference for edge placement errors of exposure patterns obtained by photolithography simulation.

[0040] After optical proximity correction is performed on the first target pattern 100, the obtained pattern is used to make a mask, and then a photolithography process is performed using the mask to form a corresponding mask pattern on a wafer.

[0041] The second target pattern 200 is a design pattern of the front layer, that is, the mask pattern corresponding to the second target pattern 200 formed on the wafer is located below the mask pattern corresponding to the first target pattern 100 formed on the wafer.

[0042] In this embodiment, the projection of the second target graphic 200 in the current layer has an overlapping portion with the first target graphic 100 .

[0043] The projection of the second target graphic 200 in the current layer of the plate has an overlapping portion with the first target graphic 100, which means that the projection of the second target graphic 200 in the current layer of the plate intersects with the first target graphic 100. During the corresponding exposure process of the first target graphic 100, the graphic structure corresponding to the second target graphic 200 will affect the reflection and scattering of light.

[0044] In this embodiment, in the second target pattern 200 of the front-layer layer, the structure corresponding to the second target pattern 200 on the wafer has a three-dimensional topography.

[0045] Specifically, in this embodiment, in the second target pattern 200 of the front layer, the second target pattern 200 is a gate pattern.

[0046] The gate pattern is used to form a gate structure on a wafer, and the gate structure is usually arranged in an array on the wafer.

[0047] In this embodiment, the layer plate layer further includes a boundary pattern (not shown) located at the boundary of the first target pattern 100 and in contact with the first target pattern 100 .

[0048] As an example, the first target graphic 100 is a gate graphic, corresponding to a gate structure formed on a wafer, and the sidewalls of the gate structure are usually formed with sidewalls. Therefore, a sidewall graphic in contact with the gate graphic is formed at the boundary of the gate graphic, that is, a boundary graphic in contact with the first target graphic 100 is formed at the boundary of the first target graphic 100.

[0049] In this embodiment, in a first target pattern 100 of a current layer, the current layer has a first mask parameter.

[0050] According to actual needs, the layer plate has corresponding first mask plate parameters.

[0051] Specifically, in this embodiment, the first mask parameter includes: one or more of a transmission rate, a mask deviation, and an angle cut.

[0052] Among them, the transmission rate refers to the efficiency of light transmission during the exposure process of the mask. For example, when the light source illuminates the mask, the transmission rate is 80%, which indicates that the light transmittance is 80%; the mask bias refers to the deviation between the designed pattern of the mask and the pattern on the mask obtained by production; the corner chop is a key indicator of the quality of the mask, which has a great influence on the critical dimension of the photoresist (ADI CD).

[0053] Combined with reference Figures 3 to 6 , execute step S2: according to the first target graphic 100 and the second target graphic 200, obtain the derived graphic 400, and the derived graphic 400 is located in the virtual version layer.

[0054] The structure corresponding to the derived graphic 400 formed on the wafer is a structure that will have an impact on the corresponding exposure process of the first target graphic 100. When the derived graphic 400 is obtained, the derived graphic 400 will be used as a correction influencing factor in the subsequent optical proximity correction process. Moreover, the derived graphic 400 is located in the virtual plate layer, that is, the derived graphic 400 is only used for optical proximity correction processing, and will not be exposed to the wafer, so it will not affect the formation of the original structure on the wafer.

[0055] refer to Figure 3 In this embodiment, according to the first target graphic 100 and the second target graphic 200, the derived graphic 400 is obtained, including: projecting the second target graphic 200 into the current layer.

[0056] The second target graphic 200 is projected into the current layer, so as to obtain the derived graphic 400 according to the projection of the second target graphic 200 and the first target graphic 100 .

[0057] refer to Figures 3 to 6 In this embodiment, a derived graphic 400 is obtained according to the projection graphic 300 of the second target graphic 200 in the current layer and the first target graphic 100.

[0058] Specifically, refer to Figure 3 In this embodiment, according to the first target graphic 100 and the second target graphic 200, the derived graphic 400 is obtained, which also includes: before obtaining the derived graphic 400 according to the projection graphic 300 of the second target graphic 200 in the current layer and the first target graphic 100, the projection of the second target graphic 200 in the current layer is enlarged according to the size of the boundary graphic, and the enlarged projection is obtained as the projection graphic 300.

[0059] When the layer plate layer also includes a boundary graphic located at the boundary of the first target graphic 100 and in contact with the first target graphic 100, during the exposure process of the second target graphic 200, the corresponding structure of the boundary graphic on the wafer will also be affected. Therefore, the projection of the second target graphic 200 is enlarged and the influence of the boundary graphic is also taken into account, which is beneficial to further improve the accuracy of the optical proximity correction processing of the first target graphic 100.

[0060] It should be noted that, in actual application, the projection size of the second target graphic 200 in the current layer is enlarged according to the size of the boundary graphic. The enlarged projection graphic 300 may or may not completely cover the boundary graphic.

[0061] refer to Figure 4 According to the projection graphic 300 of the second target graphic 200 in the current layer and the first target graphic 100, a derived graphic 400 is obtained, including: splitting the projection graphic 300 of the second target graphic 200 in the current layer into different types of feature parts according to specific positions.

[0062] Since different specific positions of the second target graphic 200 have different effects on the exposure of the first target graphic 100, and different specific positions of the second target graphic 200 have different degrees of influence during the optical proximity correction process, the projection graphic 300 of the second target graphic 200 in the current plate layer is split into different types of feature parts according to the specific positions, and then the parameters of the corresponding virtual plate layer are set according to the type of the feature parts, taking into account the different effects of different specific positions of the second target graphic 200, which is conducive to improving the processing accuracy of the subsequent optical proximity correction process.

[0063] Specifically, in this embodiment, the specific position includes multiple ones of an edge 301 extending in the horizontal direction, an edge 302 extending in the vertical direction, a corner 303 and a top surface 304 .

[0064] It should be noted that, in practical applications, according to the actual processing accuracy required and the difference in impact of each specific position, the projection graphic 300 can be split into multiple types of edges 301 extending in the horizontal direction, edges 302 extending in the vertical direction, corners 303 and top surfaces 304. In other words, the projection graphic 300 can be split into edges 301 extending in the horizontal direction, edges 302 extending in the vertical direction, corners 303 and top surfaces 304, with high processing accuracy. The projection graphic 300 can also be split into any one or two of the edges 301 extending in the horizontal direction, edges 302 extending in the vertical direction, corners 303 and top surfaces 304, and the remaining part of the projection graphic 300, with high processing efficiency.

[0065] refer to Figure 5 , obtain the intersection of the projection graphic 300 of the second target graphic 200 in the current layer and the first target graphic 100 as the initial derived graphic (not shown).

[0066] An initial derived graph is obtained, which is used as a basis for subsequently obtaining a derived graph 400 .

[0067] In this embodiment, the closed graphic area enclosed by the first target graphic 100 is a light-transmitting area in the subsequent exposure process, and the second target graphic 200 located outside the first target graphic 100 will hardly affect the exposure of the first target graphic 100. Therefore, the intersection of the projection graphic 300 of the second target graphic 200 in the current layer and the first target graphic 100 is obtained, and the part that has an impact on the exposure process of the first target graphic 100 is obtained as the initial derived graphic, which is conducive to more accurate optical proximity correction processing, and is conducive to reducing unnecessary calculation waste and improving calculation efficiency.

[0068] In this embodiment, an AND Boolean operation is used to obtain the intersection of the projection graphic 300 of the second target graphic 200 in the current layer and the first target graphic 100. The AND Boolean operation is used to obtain the intersection of the projection graphic 300 of the second target graphic 200 in the current layer and the first target graphic 100, which is simple and easy to operate, and the obtained intersection is more accurate.

[0069] In this embodiment, the initial derived graphics are split, and characteristic parts of the same type are used as derived graphics 400. The derived graphics 400 of the same type are set in a virtual version layer to obtain multiple virtual version layers.

[0070] The same type of derived graphics 400 is set in a virtual plate layer to obtain multiple virtual plate layers. The derived graphics 400 in each virtual plate layer are of the same type, so that the parameters of each virtual plate layer can be set separately to simulate the influence of each type of derived graphics 400 in the optical proximity correction processing.

[0071] It should be noted that Figure 5 The same type of derived graphics 400 are indicated by the same fill pattern.

[0072] refer to Figure 6 In other embodiments, the projection graphic of the second target graphic in the current layer may not be split into different types of feature parts according to specific positions. In this case, a derived graphic is obtained according to the projection graphic of the second target graphic in the current layer and the first target graphic, including: obtaining the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic as the derived graphic.

[0073] In this embodiment, the derived graphic 400 is obtained according to the first target graphic 100 and the second target graphic 200 , and further includes: setting a second mask parameter of a virtual layer corresponding to the derived graphic 400 .

[0074] Specifically, in this embodiment, for the type of derived graphics 400 in each virtual layer, the second mask parameters corresponding to each virtual layer are set respectively.

[0075] In this embodiment, the second mask parameters include: one or more of a transmission rate, a mask deviation and an angle cut.

[0076] Specifically, in this embodiment, the second mask parameters of each virtual layer are set according to actual needs to simulate actual exposure conditions. For example, the transmission rate of the virtual layer should be lower than that of the current layer.

[0077] Combined with reference Figures 7 to 10 , executing step S3: combining the first target graphic 100 and the derived graphic 400, performing optical proximity correction processing on the first target graphic 100.

[0078] In this embodiment, a model-based optical proximity correction (MB-OPC) process is used to perform an optical proximity correction process on the first target pattern 100. During the correction process, an optical model and a photochemical reaction model of a photoresist are used to calculate a simulated exposure pattern of the first target pattern 100 after corresponding exposure. The model-based optical proximity correction process identifies the edge corresponding to the contour of the first target pattern 100. The simulated exposure pattern after exposure is compared with the identified contour of the first target pattern 100. The difference between them is called edge placement error (EPE). The edge placement error is an indicator used to measure the correction quality. The smaller the edge placement error, the closer the pattern after exposure is to the first target pattern 100.

[0079] In this embodiment, the projection of the second target graphic 200 in the current plate layer has an overlapping portion with the first target graphic 100, and the exposure size of the first target graphic 100 will be affected by the second target graphic 200. Therefore, the derived graphic 400 is obtained according to the first target graphic 100 and the second target graphic 200, and the optical proximity correction processing is performed on the first target graphic 100 in combination with the first target graphic 100 and the derived graphic 400. This can take the influence of the second target graphic 200 on the first target graphic 100 into account, which is conducive to more accurate optical proximity correction processing of the first target graphic 100 and improves the correction accuracy of the optical proximity correction method.

[0080] In this embodiment, optical proximity correction processing is performed on the first target graphic 100 in combination with the first target graphic 100 and the derived graphic 400, including: combining the first target graphic 100 and the derived graphic 400 to obtain a simulated exposure graphic corresponding to the first target graphic 100 and a corresponding corrected graphic.

[0081] The simulated exposure pattern is used as a reference for obtaining edge placement errors, and the corrected pattern is used to make a mask.

[0082] In this embodiment, after the optical proximity correction processing is performed on the first target pattern 100 in combination with the first target pattern 100 and the derived pattern 400, the correction method further includes: determining whether the simulated exposure pattern meets the correction requirement. Determining whether the simulated exposure pattern meets the correction requirement is used to determine whether an iterative cycle of optical proximity correction processing is required.

[0083] Specifically, in this embodiment, when the simulated exposure pattern does not meet the correction requirements, the corrected pattern is used as the first target pattern 100 to return and execute the derived pattern 400 obtained according to the first target pattern 100 and the second target pattern 200; when the simulated exposure pattern meets the correction requirements, the optical proximity correction processing is completed.

[0084] Specifically, in this embodiment, combining the first target pattern 100 and the derived pattern 400 to obtain a simulated exposure pattern corresponding to the first target pattern 100 includes: obtaining a first aerial image of the first target pattern 100 .

[0085] The first aerial image of the first target pattern 100 is the light intensity distribution corresponding to the first target pattern 100 .

[0086] Specifically, in this embodiment, an optical model is used to acquire a first aerial image of the first target pattern.

[0087] In this embodiment, in acquiring the first aerial image of the first target pattern 100 , the first aerial image is acquired according to the first mask parameters.

[0088] The first mask parameters characterize the specific conditions of exposure, and therefore, the first aerial image is acquired according to the first mask parameters.

[0089] In this embodiment, a second aerial image of the derived graph 400 is acquired.

[0090] The second aerial image of the derived pattern 400 is the light intensity distribution corresponding to the derived pattern 400 .

[0091] Specifically, in this embodiment, an optical model is used to acquire the second aerial image of the derived pattern.

[0092] In this embodiment, in acquiring the second aerial image of the derived pattern 400 , the second aerial image is acquired according to the second mask parameters.

[0093] The second mask parameters characterize the specific conditions of exposure, and therefore, the second aerial image is acquired according to the second mask parameters.

[0094] In this embodiment, the first aerial image and the second aerial image are superimposed to obtain a target aerial image.

[0095] The first aerial image and the second aerial image are superimposed to obtain a target aerial image, that is, the influence of the derived graph 400 on the exposure situation is taken into consideration.

[0096] In this embodiment, a corresponding simulated exposure pattern is acquired according to the target aerial image.

[0097] After superimposing the first spatial image and the second spatial image, the corresponding simulated exposure pattern is obtained according to the target spatial image. That is to say, the obtained simulated exposure pattern is a simulated exposure pattern that takes the exposure influence of the second target pattern 100 into account, so that optical proximity correction processing that takes the influence of the front layer three-dimensional structure into account can be performed.

[0098] Specifically, in this embodiment, a resist model is used to obtain a corresponding simulated exposure pattern according to the target aerial image.

[0099] In this embodiment, whether the simulated exposure pattern meets the correction requirements is determined by judging whether the edge placement error of the simulated exposure pattern reaches the correction standard. When the edge placement error of the simulated exposure pattern reaches the correction standard, the simulated exposure pattern is judged to meet the correction requirements; when the edge placement error of the simulated exposure pattern does not reach the correction standard, the simulated exposure pattern is judged to not meet the correction requirements.

[0100] In this embodiment, multiple optical proximity correction processing cycles are iterated until the edge placement error converges and the optical proximity correction processing is completed.

[0101] It should be noted that, in this embodiment, Figure 7 As shown in FIG. 1 , when the overlap between the projections of the first target pattern 100 and the second target pattern 200 is small, Figure 8 As shown, the conventional optical proximity correction model can be used to perform correction processing. In the iterative correction processing, at the corresponding node (such as Figure 8 As shown in point A in the figure, the optical proximity correction model of this embodiment is inserted to perform the optical proximity correction process of this embodiment; Fig. 9 As shown in FIG. 1 , when the projection overlaps the projections of the first target pattern 100 and the second target pattern 200, the Fig.10 As shown, the optical proximity correction model of this embodiment can be used throughout the entire process to perform the optical proximity correction processing of this embodiment.

[0102] Correspondingly, the present invention also provides an optical proximity correction system. Fig.11 It is a functional block diagram of an embodiment of an optical proximity correction system of the present invention.

[0103] In this embodiment, the optical proximity correction system 50 includes: a graphics providing unit 501, which is used to provide a first target graphics of a current layer and a second target graphics of a previous layer, and the projection of the second target graphics in the current layer has an overlapping part with the first target graphics; a derived graphics acquisition unit 502, which is used to acquire a derived graphics according to the first target graphics and the second target graphics, and the derived graphics are located in a virtual layer; an optical proximity correction unit 503, which is used to perform optical proximity correction processing on the first target graphics in combination with the first target graphics and the derived graphics.

[0104] The graphic providing unit 501 is used to provide a first target graphic of a current layer and a second target graphic of a previous layer.

[0105] The first target pattern is a design pattern of the current layer, and is used as a reference for edge placement errors of exposure patterns obtained by photolithography simulation.

[0106] After optical proximity correction is performed on the first target pattern, the obtained pattern is used to make a mask plate, and then a photolithography process is performed using the mask plate to form a corresponding mask pattern on a wafer.

[0107] The second target pattern is a design pattern of the front layer, that is, the mask pattern corresponding to the second target pattern formed on the wafer is located below the mask pattern corresponding to the first target pattern formed on the wafer.

[0108] In this embodiment, the projection of the second target pattern in the current layer has an overlapping portion with the first target pattern.

[0109] The projection of the second target graphic in the current layer has an overlapping part with the first target graphic, which means that the projection of the second target graphic in the current layer intersects with the first target graphic. During the corresponding exposure process of the first target graphic, the graphic structure corresponding to the second target graphic will affect the reflection and scattering of light.

[0110] In this embodiment, in the second target pattern of the front layer, the structure corresponding to the second target pattern on the wafer has a three-dimensional topography.

[0111] Specifically, in this embodiment, in the second target pattern of the front layer, the second target pattern is a gate pattern.

[0112] The gate pattern is used to form a gate structure on a wafer, and the gate structure is usually arranged in an array on the wafer.

[0113] In this embodiment, the layer plate layer further includes a boundary graphic located at the boundary of the first target graphic and in contact with the first target graphic.

[0114] As an example, the first target pattern is a gate pattern, corresponding to a gate structure formed on a wafer, and the sidewalls of the gate structure are usually formed with sidewalls. Therefore, a sidewall pattern in contact with the gate pattern is formed at the boundary of the gate pattern, that is, a boundary pattern in contact with the first target pattern is formed at the boundary of the first target pattern.

[0115] In this embodiment, in a first target pattern of a layer, the layer has a first mask parameter.

[0116] According to actual needs, the layer plate has corresponding first mask plate parameters.

[0117] Specifically, in this embodiment, the first mask parameter includes: one or more of a transmission rate, a mask deviation, and an angle cut.

[0118] Among them, the transmission rate refers to the efficiency of light transmission during the exposure process of the mask. For example, when the light source illuminates the mask, the transmission rate is 80%, which indicates that the light transmittance is 80%; the mask bias refers to the deviation between the designed pattern of the mask and the pattern on the mask obtained by production; the corner chop is a key indicator of the quality of the mask, which has a great influence on the critical dimension of the photoresist (ADI CD).

[0119] The derived graphics acquisition unit 502 is used to acquire derived graphics according to the first target graphics and the second target graphics, and the derived graphics are located in the virtual version layer.

[0120] The structure corresponding to the derived pattern formed on the wafer is a structure that will have an impact on the corresponding exposure process of the first target pattern. When the derived pattern is obtained, the derived pattern will be used as a correction influencing factor in the subsequent optical proximity correction process. Moreover, the derived pattern is located in the virtual plate layer, that is, the derived pattern is only used for optical proximity correction processing, and will not be exposed to the wafer, so it will not affect the formation of the original structure on the wafer.

[0121] In this embodiment, obtaining a derived graphic according to the first target graphic and the second target graphic includes: projecting the second target graphic into the current layer.

[0122] The second target graphic is projected onto the current layer, so as to obtain a derived graphic based on the projection of the second target graphic and the first target graphic.

[0123] In this embodiment, the derived graphic is obtained according to the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic.

[0124] Specifically, in this embodiment, a derived graphic is obtained based on the first target graphic and the second target graphic, and the method also includes: before obtaining the derived graphic based on the projection graphic of the second target graphic in the current layer and the first target graphic, the projection of the second target graphic in the current layer is enlarged according to the size of the boundary graphic, and the enlarged projection is obtained as the projection graphic.

[0125] When the layer plate layer also includes a boundary graphic located at the boundary of the first target graphic and in contact with the first target graphic, during the exposure process of the second target graphic, the corresponding structure of the boundary graphic on the wafer will also be affected. Therefore, the projection of the second target graphic is enlarged and the influence of the boundary graphic is also taken into account, which is beneficial to further improve the accuracy of the optical proximity correction processing of the first target graphic.

[0126] It should be noted that, in actual application, the size of the projection of the second target graphic in the current layer is enlarged according to the size of the boundary graphic. The enlarged projection graphic may or may not completely cover the boundary graphic.

[0127] In this embodiment, a derived graphic is obtained based on the projection graphic of the second target graphic in the current layer and the first target graphic, including: splitting the projection graphic of the second target graphic in the current layer into different types of feature parts according to specific positions.

[0128] Since different specific positions of the second target graphic have different effects on the exposure of the first target graphic, and different specific positions of the second target graphic have different degrees of influence during the optical proximity correction processing, the projection graphic of the second target graphic in the current plate layer is split into different types of feature parts according to the specific positions, and then the parameters of the corresponding virtual plate layer are set according to the type of the feature parts, taking the different effects of different specific positions of the second target graphic into consideration, which is beneficial to improving the processing accuracy of the subsequent optical proximity correction processing.

[0129] Specifically, in this embodiment, the specific position includes multiple ones of an edge extending in a horizontal direction, an edge extending in a vertical direction, a corner, and a top surface.

[0130] It should be noted that, in practical applications, according to the actual required processing accuracy and the difference in impact of each specific position, the projection figure can be split into multiple types of edges extending in the horizontal direction, edges extending in the vertical direction, corners and top surfaces. In other words, the projection figure can be split into edges extending in the horizontal direction, edges extending in the vertical direction, corners and top surfaces, with higher processing accuracy. The projection figure can also be split into any one or two of the edges extending in the horizontal direction, edges extending in the vertical direction, corners and top surfaces, as well as the remaining part of the projection figure, with higher processing efficiency.

[0131] In this embodiment, the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic is obtained as the initial derived graphic.

[0132] Gets the initial derived graph, which is used as the basis for subsequent derived graphs.

[0133] In this embodiment, the closed graphic area enclosed by the first target graphic is a light-transmitting area in the subsequent exposure process, and the second target graphic located outside the first target graphic will hardly affect the exposure of the first target graphic. Therefore, the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic is obtained, and the part that has an impact on the exposure process of the first target graphic is obtained as the initial derived graphic, which is conducive to more accurate optical proximity correction processing, and is conducive to reducing unnecessary calculation waste and improving calculation efficiency.

[0134] In this embodiment, an AND Boolean operation is used to obtain the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic.

[0135] The AND Boolean operation is used to obtain the intersection of the projection figure of the second target figure in the current layer and the first target figure. This is simple and easy to operate, and the obtained intersection is more accurate.

[0136] In this embodiment, the initial derived graphics are split, characteristic parts of the same type are used as derived graphics, and the derived graphics of the same type are set in a virtual version layer to obtain multiple virtual version layers.

[0137] The same type of derived graphics is set in a virtual plate layer to obtain multiple virtual plate layers, and the type of derived graphics in each virtual plate layer is the same, so that the parameters of each virtual plate layer can be set separately to simulate the influence of each type of derived graphics in the optical proximity correction processing.

[0138] In other embodiments, instead of splitting the projection graphic of the second target graphic in the current layer into different types of feature parts according to specific positions, a derived graphic is obtained based on the projection graphic of the second target graphic in the current layer and the first target graphic, including: obtaining the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic as the derived graphic.

[0139] In this embodiment, the derived graphic is obtained according to the first target graphic and the second target graphic, and further includes: setting a second mask parameter of a virtual layer corresponding to the derived graphic.

[0140] Specifically, in this embodiment, for the derived graphic type in each virtual plate layer, the second mask parameters corresponding to each virtual plate layer are set respectively.

[0141] In this embodiment, the second mask parameters include: one or more of a transmission rate, a mask deviation and an angle cut.

[0142] Specifically, in this embodiment, the second mask parameters of each virtual layer are set according to actual needs to simulate actual exposure conditions. For example, the transmission rate of the virtual layer should be lower than that of the current layer.

[0143] The optical proximity correction unit 503 is used to perform optical proximity correction processing on the first target pattern in combination with the first target pattern and the derived pattern.

[0144] In this embodiment, a model-based optical proximity correction (MB-OPC) process is used to perform an optical proximity correction process on the first target pattern. During the correction process, an optical model and a photochemical reaction model of a photoresist are used to calculate a simulated exposure pattern of the first target pattern after corresponding exposure. The model-based optical proximity correction process identifies the edge corresponding to the contour of the first target pattern. The simulated exposure pattern after exposure is compared with the identified contour of the first target pattern. The difference between them is called edge placement error (EPE). The edge placement error is an indicator used to measure the correction quality. The smaller the edge placement error, the closer the pattern after exposure is to the first target pattern.

[0145] In this embodiment, the projection of the second target graphic in the current plate layer has an overlapping portion with the first target graphic, and the exposure size of the first target graphic will be affected by the second target graphic. Therefore, a derived graphic is obtained according to the first target graphic and the second target graphic, and an optical proximity correction process is performed on the first target graphic in combination with the first target graphic and the derived graphic. This can take the influence of the second target graphic on the first target graphic into account, which is conducive to more accurate optical proximity correction processing of the first target graphic and improves the correction accuracy of the optical proximity correction method.

[0146] In this embodiment, optical proximity correction processing is performed on the first target pattern in combination with the derived pattern, including: combining the first target pattern and the derived pattern to obtain a simulated exposure pattern corresponding to the first target pattern and a corresponding corrected pattern.

[0147] The simulated exposure pattern is used as a reference for obtaining edge placement errors, and the corrected pattern is used to make a mask.

[0148] In this embodiment, after performing optical proximity correction processing on the first target pattern in combination with the first target pattern and the derived pattern, the method further includes: determining whether the simulated exposure pattern meets the correction requirement.

[0149] It is determined whether the simulated exposure pattern meets the correction requirements to determine whether an iterative cycle of optical proximity correction processing is required.

[0150] Specifically, in this embodiment, when the simulated exposure pattern does not meet the correction requirements, the corrected pattern is used as the first target pattern to return and execute the derived pattern obtained according to the first target pattern and the second target pattern; when the simulated exposure pattern meets the correction requirements, the optical proximity correction processing is completed.

[0151] Specifically, in this embodiment, combining the first target pattern and the derived pattern to obtain a simulated exposure pattern corresponding to the first target pattern includes: obtaining a first aerial image of the first target pattern.

[0152] The first aerial image of the first target pattern is the light intensity distribution corresponding to the first target pattern.

[0153] Specifically, in this embodiment, an optical model is used to acquire a first aerial image of the first target pattern.

[0154] In this embodiment, in acquiring the first aerial image of the first target pattern, the first aerial image is acquired according to the first mask parameters.

[0155] The first mask parameters characterize the specific conditions of exposure, and therefore, the first aerial image is acquired according to the first mask parameters.

[0156] In this embodiment, a second aerial image of the derived graphic is acquired.

[0157] The second aerial image of the derived pattern is the light intensity distribution corresponding to the derived pattern.

[0158] Specifically, in this embodiment, an optical model is used to acquire the second aerial image of the derived pattern.

[0159] In this embodiment, in acquiring the second aerial image of the derived pattern, the second aerial image is acquired according to the second mask parameters.

[0160] The second mask parameters characterize the specific conditions of exposure, and therefore, the second aerial image is acquired according to the second mask parameters.

[0161] In this embodiment, the first aerial image and the second aerial image are superimposed to obtain a target aerial image.

[0162] The first aerial image and the second aerial image are superimposed to obtain a target aerial image, that is, the influence of the derived image on the exposure situation is taken into account.

[0163] In this embodiment, a corresponding simulated exposure pattern is acquired according to the target aerial image.

[0164] After superimposing the first spatial image and the second spatial image, the corresponding simulated exposure pattern is obtained according to the target spatial image. That is to say, the obtained simulated exposure pattern is a simulated exposure pattern that takes the exposure influence of the second target pattern into account, so that optical proximity correction processing can be performed that takes the influence of the three-dimensional structure of the front layer into account.

[0165] Specifically, in this embodiment, a resist model is used to obtain a corresponding simulated exposure pattern according to the target aerial image.

[0166] In this embodiment, whether the simulated exposure pattern meets the correction requirements is determined by judging whether the edge placement error of the simulated exposure pattern reaches the correction standard. When the edge placement error of the simulated exposure pattern reaches the correction standard, the simulated exposure pattern is judged to meet the correction requirements; when the edge placement error of the simulated exposure pattern does not reach the correction standard, the simulated exposure pattern is judged to not meet the correction requirements.

[0167] In this embodiment, multiple optical proximity correction processing cycles are iterated until the edge placement error converges and the optical proximity correction processing is completed.

[0168] It should be noted that, in the present embodiment, when the overlapping portion of the projections of the first target figure and the second target figure is small, the conventional optical proximity correction model may be used to perform correction processing first, and during the iterative correction processing, the optical proximity correction model of the present embodiment may be inserted into the corresponding node to perform the optical proximity correction processing of the present embodiment; when the overlapping portion of the projections of the first target figure and the second target figure is large, the optical proximity correction model of the present embodiment may be used throughout the entire process to perform the optical proximity correction processing of the present embodiment.

[0169] Correspondingly, the present invention further provides a mask plate, comprising: a pattern obtained by using the optical proximity correction method provided by an embodiment of the present invention.

[0170] It can be seen from the aforementioned embodiments that if the projection of the second target pattern in the current plate layer has an overlapping portion with the first target pattern, the exposure size of the first target pattern will be affected by the second target pattern. Therefore, a derived pattern is obtained based on the first target pattern and the second target pattern, and an optical proximity correction process is performed on the first target pattern in combination with the first target pattern and the derived pattern. This can take the influence of the second target pattern on the first target pattern into account, which is conducive to more accurate optical proximity correction processing of the first target pattern and improves the correction accuracy of the optical proximity correction method.

[0171] The embodiment of the present invention further provides a device, which can implement the optical proximity correction method provided by the embodiment of the present invention by loading the above optical proximity correction method in the form of a program. An optional hardware structure of the terminal device provided by the embodiment of the present invention can be as follows Fig.12 As shown, it includes: at least one processor 01, at least one communication interface 02, at least one memory 03 and at least one communication bus 04.

[0172] In this embodiment, the number of processor 01, communication interface 02, memory 03, and communication bus 04 is at least one, and the processor 01, communication interface 02, and memory 03 communicate with each other 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 an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiment of the present invention. The memory 03 may include a high-speed RAM memory, and may also include a non-volatile memory (NVM), such as at least one disk storage. 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 optical proximity correction method provided in the embodiment of the present invention.

[0173] It should be noted that the above-mentioned terminal device may also include other devices (not shown) that may not be necessary for understanding the contents disclosed in the embodiments of the present invention; given that these other devices may not be necessary for understanding the contents disclosed in the embodiments of the present invention, the embodiments of the present invention will not introduce them one by one.

[0174] An embodiment of the present invention further provides a storage medium, wherein 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.

[0175] Embodiments of the present invention may be implemented by various means such as hardware, firmware, software or a combination thereof. In a hardware configuration, the method according to an exemplary embodiment of the present invention may 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 a firmware or software configuration, embodiments of the present invention may be implemented in the form of modules, processes, functions, etc. The software code may be stored in a memory unit and executed by a processor. The memory unit is located inside or outside the processor and may send data to the processor and receive data from the processor via various known means.

[0176] 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 shall be subject to the scope defined by the claims.

Claims

1. An optical proximity correction method, characterized in that: include: Providing a first target graphic of the current layer and a second target graphic of the previous layer, wherein a projection of the second target graphic in the current layer has an overlapping portion with the first target graphic; According to the first target graphic and the second target graphic, a derived graphic is obtained, wherein the derived graphic is located in a virtual version layer; The first target pattern and the derived pattern are combined to perform optical proximity correction processing on the first target pattern.

2. The optical proximity correction method according to claim 1, wherein: Acquiring a derived graph according to the first target graph and the second target graph, including: Projecting the second target graphic onto the current layer; The derived graphic is obtained according to the projection graphic of the second target graphic in the current layer and the first target graphic.

3. The optical proximity correction method according to claim 2, wherein: The current layer also includes a boundary graphic located at the boundary of the first target graphic and in contact with the first target graphic; The method of obtaining a derived graphic based on the first target graphic and the second target graphic also includes: before obtaining the derived graphic based on the projection graphic of the second target graphic in the current layer and the first target graphic, enlarging the projection of the second target graphic in the current layer according to the size of the boundary graphic, and obtaining the enlarged projection as the projection graphic.

4. The optical proximity correction method according to claim 2, wherein: Obtaining the derived graphic according to the projection graphic of the second target graphic in the current layer and the first target graphic, including: Obtaining the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic as the derived graphic; or, Splitting the projection graphic of the second target graphic in the current layer into different types of characteristic parts according to specific positions; Obtaining the intersection of the projection figure of the second target figure in the current layer and the first target figure as an initial derived figure; The initial derived graph is split, and characteristic parts of the same type are used as the derived graph.

5. The optical proximity correction method according to claim 4, wherein: The specific position includes multiple ones of an edge extending in a horizontal direction, an edge extending in a vertical direction, a corner, and a top surface.

6. The optical proximity correction method according to claim 4, wherein: The AND Boolean operation is used to obtain the intersection of the projection graphic of the second target graphic in the current layer and the first target graphic.

7. The optical proximity correction method according to claim 1, wherein: Performing optical proximity correction processing on the first target pattern in combination with the first target pattern and the derived pattern, including: acquiring a simulated exposure pattern and a corresponding corrected pattern corresponding to the first target pattern in combination with the first target pattern and the derived pattern; After performing optical proximity correction processing on the first target pattern in combination with the first target pattern and the derived pattern, the correction method further includes: determining whether the simulated exposure pattern meets the correction requirement; When the simulated exposure pattern does not meet the correction requirement, returning to obtain a derived pattern according to the first target pattern and the second target pattern using the corrected pattern as the first target pattern; When the simulated exposure pattern meets the correction requirement, the optical proximity correction process is completed.

8. The optical proximity correction method according to claim 7, wherein: By judging whether the edge placement error of the simulated exposure pattern reaches the correction standard, judging whether the simulated exposure pattern meets the correction requirement, when the edge placement error of the simulated exposure pattern reaches the correction standard, judging that the simulated exposure pattern meets the correction requirement; When the edge placement error of the simulated exposure pattern does not meet the correction standard, it is determined that the simulated exposure pattern does not meet the correction requirement.

9. The optical proximity correction method according to claim 7, wherein: Combining the first target pattern and the derived pattern, obtaining a simulated exposure pattern corresponding to the first target pattern, including: obtaining a first aerial image of the first target pattern; Acquire a second aerial image of the derived graph; Superimposing the first aerial image and the second aerial image to obtain a target aerial image; According to the target aerial image, the corresponding simulated exposure pattern is acquired.

10. The optical proximity correction method according to claim 9, wherein: Acquire a first aerial image of the first target graphic using an optical model; Acquire a second aerial image of the derived graph using an optical model; A light resistance model is used to obtain the corresponding simulated exposure pattern according to the target aerial image.

11. The optical proximity correction method according to claim 9, wherein: The current layer has a first mask parameter; According to the first target graphic and the second target graphic, a derived graphic is obtained, and further comprising: setting a second mask parameter of a virtual layer corresponding to the derived graphic; In acquiring a first aerial image of the first target pattern, the first aerial image is acquired according to the first mask parameters; In acquiring the second aerial image of the derived pattern, the second aerial image is acquired according to the second mask parameters.

12. The optical proximity correction method according to claim 11, wherein: The first mask parameter and the second mask parameter both include: one or more of a transmission rate, a mask deviation and an angle cut.

13. The optical proximity correction method according to claim 1, wherein: In providing a second target pattern of the front layer, the second target pattern is a gate pattern.

14. An optical proximity correction system, characterized in that: include: A graphics providing unit, used for providing a first target graphic of a current layer and a second target graphic of a previous layer, wherein a projection of the second target graphic in the current layer has an overlapping portion with the first target graphic; A derived graphics acquisition unit, configured to acquire a derived graphics according to the first target graphics and the second target graphics, wherein the derived graphics are located in a virtual version layer; The optical proximity correction unit is used to perform optical proximity correction processing on the first target pattern in combination with the derived pattern.

15. A mask, characterized in that: include: A pattern obtained using the optical proximity correction method as described in any one of claims 1 to 13.

16. A device, characterized in that The method comprises at least one memory and at least one processor, wherein the memory stores 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 to 13.

17. A storage medium, characterized in that: 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 as described in any one of claims 1-13.

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