CN116661234A - OPC correction method - Google Patents

Abstract

The invention discloses an OPC correction method, comprising: step 1, providing an initial target layer and setting the minimum resolution size of a mask; step 2, selecting the first object in the initial target layer that will violate the mask rule check in the subsequent MBOPC correction One figure; step 3, carry out segmentation processing to the first figure and divide each side of the first figure into a plurality of segments, the segments include corner segments and intermediate segments, and the initial target layer after segment processing is the second Target layer; step 4, perform MBOPC correction based on the second target layer and obtain the mask layer, MBOPC correction includes multiple iterative cycle operations, in each iterative cycle operation, the angle segment and the middle segment are separately corrected, through The corner segment controls the corner size of the first graphic in the mask layer, and the middle segment controls the area of the first graphic in the mask layer. The invention can realize the adjustment and control of the figure size in the mask plate layer, and can make the exposure figure conform to the target value and meet the mass production requirement under the condition of not violating the MRC.

Description

OPC correction method

technical field

The invention relates to a semiconductor integrated circuit manufacturing method, in particular to an optical proximity correction (Optical Proximity Correction, OPC) method.

Background technique

With the reduction of semiconductor manufacturing process nodes, especially the process nodes below 14nm, the critical dimensions of the pattern are close to the limit of lithography, and the pattern structure is relatively more complex, and the mask correction is facing a huge challenge. In the actual exposure process, due to light interference and diffraction effects, the exposure pattern will be distorted, including rounded corners and shortened lines. Optical proximity correction (OPC) has become an essential process link. The essence of the OPC correction process is an iterative process. Through model simulation, the predicted contour figure (contour) is infinitely close to the target value (target). When the mask rule check (Mask Rule Check, MRC) rule (Rule) is the minimum resolution size of the mask, the edge will not move, so as to avoid violating the MRC. In the correction process, the MRC rules are usually artificially set in advance, including the mask analysis minimum CD and Space. The set MRC rules are generally determined by the process node and the process capability of the Mask Shop. , The process capability of the mask shop (Mask Shop) is the minimum CD and/or Space analyzed for the mask manufacturing.

For lower process nodes, errors caused by mask fabrication variances are especially significant, in addition to normal exposure condition variations. If there is an MRC problem, there is a risk of disconnection (open) in the real exposure pattern, and the actual process window is small. The via (Via) layer acts as a connection in the actual process. Taking the layer as an example, it is a channel for communicating with the metal layer. The staggered structure is very common in the via layer. Generally, the corner-to-corner Space is very small, and it often faces MRC problems in OPC correction.

Now in conjunction with the accompanying drawings, the existing OPC correction method is described as follows:

As shown in Figure 1, it is a flowchart of an existing OPC correction method; the existing OPC correction method includes the following steps:

Step S101 , providing an initial layout. In FIG. 1 , Drawn represents an initial layout, which is formed by drawing a circuit.

In step S102, a rule-based OPC is performed on the initial layout to obtain a target layer, which is also represented by target in FIG. 1 .

As shown in Figure 2A, it is a schematic diagram of the graphic structure of the target layer in the existing OPC correction method; the target layer 201 includes a plurality of graphics 202, the graphics 202 in Figure 2A are square, and the array structure formed by the graphics 202 is a dense staggered arrangement structure, in the dense staggered arrangement structure, the diagonals of the graphics 202 are aligned and arranged periodically, and the minimum spacing of the graphics 202 is the corner-to-corner spacing d201, that is, the adjacent corners of two adjacent graphics 202 The distance between the graphs 202 is the sum of the length of the diagonals of the graph and the minimum distance. Usually, the pattern of the via hole layer adopts a square pattern 202 and adopts a dense staggered structure.

Step S103 , perform model-based OPC correction based on the target layer to obtain a mask layer, which is also represented by a mask in FIG. 1 . The model-based OPC correction includes multiple iterative loop operations.

As shown in Figure 2B, it is a schematic diagram of the graphic structure of the mask layer formed by the existing OPC correction method; the graphic 204 of the mask layer 203 corresponds to the graphic 202 in Figure 2A, and the graphic 204 is formed by adding more to the graphic 202 obtained by iterative loop operation.

Step S104 , performing MRC detection. In FIG. 1 , the MRC detection is also represented by MRC. The MRC detection needs to ensure that the critical dimension and the corner-to-corner spacing of the pattern 204 of the mask layer 203 in FIG. 2B meet the minimum analytical size of the mask specified by MRC, that is, the minimum analytical value of the critical dimension and the minimum analytical value of the spacing.

Step S104 can be inserted into each iterative cycle operation of MBOPC. When the critical dimension and the corner-to-corner spacing of the graph 204 are close to the minimum resolution value of the critical dimension and the minimum resolution value of the spacing, the edge will not move any more to avoid violating the MRC. As can be seen from FIG. 2A, in the densely staggered arrangement structure, the corner-to-corner spacing d201 of the graphics 202 is relatively small, so in the MBOPC correction, the corner-to-corner spacing of the graphics 204 in FIG. 2B is likely to be close to the minimum analytical value of the spacing. In this case, all sides of the graphic 204 will stop moving, and the entire iterative cycle operation will stop, which will easily cause the defect that the area of the graphic 204 is insufficient. When the area of the figure 204 is insufficient, the area of the exposure figure corresponding to the figure 204 formed when exposing by using the mask formed by the mask layer 203 will also be reduced; the outline figure 205 in FIG. 2B is a simulation figure of the exposure figure of the figure 204 2A, it can be seen that the contour figure 205 has a small area, which is quite different from the target figure 202 in FIG. 2A , and the off-target defect will appear.

Contents of the invention

The technical problem to be solved by the present invention is to provide an OPC correction method, which can solve the problem of violating MRC in the OPC correction and prevent the OPC correction graph from deviating from the target value.

In order to solve the problems of the technologies described above, the OPC correction method provided by the present invention is characterized in that it comprises the following steps:

Step 1. Provide the initial target layer and set the minimum resolution size of the mask.

Step 2: Selecting in the initial target layer according to the minimum resolution size of the mask template, a first pattern that will violate mask rule check in subsequent model-based OPC (model-based OPC, MBOPC) correction.

Step 3, performing segmentation (Split) processing on the first graphic, the segmentation processing divides each side of the first graphic into a plurality of segments, and each segment of each side includes an angle segment and middle segment, one vertex of the corner segment is the vertex of the edge, and the other vertex of the corner segment is the vertex of the adjacent middle segment; the segmented processed The initial target layer is the second target layer.

Step 4: Perform model-based OPC correction based on the second target layer to obtain a mask layer, the model-based OPC correction includes multiple iterative cycle operations, and in each of the iterative cycle operations, the first The corner segment and the middle segment of each side of the graphic are corrected separately, the corner size of the first graphic in the mask layer is controlled by the corner segment, and the middle segment is used to control The segment controls the area of the first pattern in the mask layer.

A further improvement is that after step four, it also includes:

Step 5: Perform a mask rule check on the mask template layer.

A further improvement is that in step 1, the initial target layer is obtained by performing rule-based OPC (rule based OPC) correction on the initial layout.

A further improvement is that the minimum resolution size of the mask includes a minimum resolution value of a critical dimension and a minimum resolution value of a spacing.

A further improvement is that, in step five, the mask rule check passes when the critical dimension of the first graphic in the mask layer is greater than the minimum resolution value of the critical dimension and the spacing is greater than the minimum resolution value of the spacing .

A further improvement is that the first figure includes a square hole figure.

A further improvement is that the square hole pattern includes a through hole layer pattern.

A further improvement is that, in the initial target layer, the array structure formed by the arrangement of each of the first patterns is a dense staggered structure, and in the dense staggered structure, the diagonals of each of the first patterns are aligned and arranged periodically, the minimum pitch of the first figure is the distance between adjacent corners of two adjacent first figures, and the step of the first figure is the diagonal line of the first figure The sum of the length and the minimum spacing.

A further improvement is that the minimum resolution size of the mask is determined by the process node and the manufacturing capability of the mask.

A further improvement is that the process node is below 14nm, and the minimum analytical value of the critical dimension and the minimum analytical value of the spacing are both 18nm or 12nm.

A further improvement is that the minimum pitch of the first pattern is less than 20nm, and the step of the first pattern is less than 115nm.

A further improvement is that the target value of the side length of the first graphic is 68nm, and the size of the corner segment in the segment processing is 5-20nm.

A further improvement is that in step 3, the segmentation process divides each of the sides of the first graphic into 3 segments, and the 3 segments include two corner segments and a the middle segment.

In the prior art, because before MBOPC, the edge of the first figure is not segmented, so in MBOPC, when the corner-to-corner spacing of the first figure is violated by MRC restrictions and the iterative cycle operation is stopped, the area of the first figure Will keep smaller, finally can make the contour figure of the first figure after MBOPC, that is, the simulation figure of the exposure figure deviate from the target value (offtarget); after the present invention provides the initial target layer, it does not directly perform model-based OPC correction, but pre-selection based on the characteristics of the patterns in the initial target layer will lead to MRC-violating first patterns in model-based OPC correction, after which these selected patterns are segmented and form the second target layer , after performing MBOPC, after each side of the first figure is segmented, the corner segment and middle segment can be corrected separately in each iterative cycle operation of MBOPC, so that the vertex angle size and the middle segment of the first figure can be adjusted The size of the area is adjusted separately. By adjusting the corner size of the first graphic, the corner-to-corner spacing of the first graphic can not violate the MRC; the area of the first graphic can be adjusted by adjusting the size of the middle area, so that Increase the area of the first figure when the corner-to-corner spacing of the first figure satisfies the regulation of MRC, the increase of the area of the first figure after MBOPC can make the outline figure conform to the regulation (ontarget) of target value, the figure after real exposure like this also Will be on target.

The present invention is particularly applicable to the OPC correction of a square pattern with a dense staggered pattern (Dense Stagger Pattern), such as a through-hole layer pattern, and can realize the size of the square pattern in the mask layer, and can be used without violating the mask MRC. The simulation contour of the exposure pattern is not only on-target, but also the process variation band (pvband) and mask error enhancement factor (meef) under the process window (process Windows, PW) conditions meet the mass production requirements.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the present invention will be described in further detail:

Fig. 1 is the flow chart of existing OPC correction method;

FIG. 2A is a schematic diagram of a graphic structure of a target layer in an existing OPC correction method;

2B is a schematic diagram of the graphic structure of the mask layer formed by the existing OPC correction method;

Fig. 3 is the flowchart of the OPC correction method of the embodiment of the present invention;

4A is a schematic diagram of the graphic structure of the initial target layer in the OPC correction method of the method of the embodiment of the present invention;

4B is a schematic diagram of the graphic structure of the second target layer in the OPC correction method of the method of the embodiment of the present invention;

4C is a schematic diagram of the graphic structure of the mask layer formed by the OPC correction method of the method of the embodiment of the present invention;

Fig. 4D is a schematic diagram of a contour pattern formed by performing exposure pattern simulation using the mask layer of Fig. 4C;

FIG. 5A is a simulation diagram of a mask layer and contour graphics formed by using the existing OPC correction method;

5B is a simulation diagram of the mask layer and contour graphics formed when the corner segment size is 5nm in the OPC correction method of the method of the embodiment of the present invention;

5C is a simulation diagram of the mask layer and contour graphics formed when the corner segment size is 10nm in the OPC correction method of the method of the embodiment of the present invention;

FIG. 5D is a simulation diagram of the mask layer and contour graphics formed when the corner segment size is 15nm in the OPC correction method of the method of the embodiment of the present invention;

FIG. 5E is a simulation diagram of a mask layer and contour graphics formed when the corner segment size is 20nm in the OPC correction method of the method of the embodiment of the present invention.

Detailed ways

As shown in Figure 3, it is a flowchart of the OPC correction method of the embodiment of the present invention; as shown in Figure 4A, it is a schematic diagram of the graphic structure of the initial target layer 301 in the OPC correction method of the embodiment of the present invention; as shown in Figure 4B, it is A schematic diagram of the graphic structure of the second target layer 301a in the OPC correction method of the method of the embodiment of the present invention; as shown in Figure 4C, it is a schematic diagram of the graphic structure of the mask layer 304 formed by the OPC correction method of the method of the embodiment of the present invention; as shown in Figure 4D 4C is a schematic diagram of an outline graphic formed by exposure graphic simulation using the mask layer 304 of FIG. 4C; the OPC correction method in the embodiment of the present invention includes the following steps:

Step 1, as shown in FIG. 4A , an initial target layer 301 is provided and the minimum resolution size of the mask is set.

In the embodiment of the present invention, the initial target layer 301 is obtained by performing rule-based OPC correction on the initial layout.

The minimum resolution size of the mask includes a minimum resolution value of a critical dimension and a minimum resolution value of a pitch.

The minimum resolution size of the mask is determined by the process node and the manufacturing capability of the mask.

In some embodiments, the process node is below 14nm, and the minimum analytical value of the CD and the minimum analytical value of the spacing are both 18nm or 12nm.

Step 2: Select the first pattern 302 in the initial target layer 301 that will violate the mask rule check in the subsequent model-based OPC correction according to the minimum resolution size of the mask template. FIG. 3A only shows the first pattern 302 in the initial target layer 301 . The initial target layer 301 also includes other types of graphics, which are not shown in FIG. 3A .

In the embodiment of the present invention, the first pattern 302 includes a square hole pattern.

In some preferred embodiments, the square hole pattern includes a through hole layer pattern.

In the initial target layer 301, the array structure formed by the arrangement of each of the first patterns 302 is a dense staggered arrangement structure, and in the dense staggered arrangement structure, the diagonal lines of each of the first patterns 302 are aligned and periodic Arranged, the minimum pitch of the first graphics 302 is the distance between the adjacent corners of two adjacent first graphics 302, that is, the corner-to-corner spacing d301, and the step of the first graphics 302 is the The sum of the length of the diagonal of the first graphic 302 and the minimum distance.

In some embodiments, the minimum pitch of the first pattern 302 is less than 20 nm, and the step of the first pattern 302 is less than 115 nm.

Step 3, as shown in Fig. 4B, carry out segment processing to described first graph 302, described segment processing divides each edge of described first graph 302 into a plurality of segments, each edge of each described edge The segment includes an angle segment 303a and an intermediate segment 303b, one vertex of the angular segment 303a is the vertex of the side, and the other vertex of the angular segment 303a is the adjacent intermediate segment 303b vertex; the broken line between the angle segment 303a and the middle segment 303b in Fig. 4B is only for visually distinguishing the angle segment 303a and the middle segment 303b, in fact Segment 303a and said intermediate segment 303b are connected together.

The initial target layer 301 after the segment processing is the second target layer 301a.

In the embodiment of the present invention, the segment processing divides each side of the first graphic 302 into three segments, and the three segments include two corner segments 303a and one corner segment 303a. Describe the middle segment 303b.

In some embodiments, the target value of the side length of the first pattern 302 is 68 nm, and the size of the corner segment 303 a in the segment processing is 5-20 nm.

Step 4, as shown in FIG. 4C, perform model-based OPC correction based on the second target layer 301a to obtain a mask layer 304, the model-based OPC correction includes multiple iterative loop operations, and each iteration In the loop operation, the corner segment 303a and the middle segment 303b of each side of the first graphic 302 are corrected separately, and the angle segment 303a is used to control the The corner size of the first figure 305 controls the area of the first figure 305 in the mask layer 304 through the middle segment 303b. In FIG. 4C, the first figure is represented by a mark 305 alone. The first graph 305 in 4C is formed by MBOPC correction of the first graph 302 in FIG. 4A . As shown in FIG. 4C, it can be seen that the separate correction of the corner segment 303a and the middle segment 303b of each side of the first graphic 302 can avoid the existing method in the MBOPC correction process. Each of the sides of the first figure 302 needs to be moved as a whole, but can be moved in sections. In this way, the size of the movement of each of the sides of the first figure 302 at the corner segment 303a and the size of the movement at the corner segment 303a can be realized. The magnitude of the movement at the middle segment 303b is different. Comparing with the first graphic 302 in the initial target layer 301 in FIG. 4A, it can be seen that the edge of the first graphic 305 after MBOPC correction in FIG. 4C is no longer smooth, and the middle segment 303b corresponds to A protruding figure 305 a is formed at the position, and the protruding figure 305 a increases the area of the first figure 305 .

Step 5: Perform a mask rule check on the mask template layer 304 .

In step 5, the mask rule check passes when the critical dimension of the first graphic 305 in the mask template layer 304 is greater than the minimum resolution value of the critical dimension and the spacing is greater than the minimum resolution value of the spacing.

As shown in FIG. 4C , the critical dimension of the first graphic 305 is the minimum width, and the spacing of the first graphic 305 is the corner-to-corner spacing d302 .

The mask rule check will be inserted into each iterative cycle operation of the model-based OPC correction, even when the corner-to-corner distance d302 is close to the minimum analytical value of the distance, the edge at the middle segment 303b can still Correction is movement, so as to avoid the defect that the entire side cannot move when the corner-to-corner distance d302 is close to the minimum analytical value of the distance in the existing method. The edge movement at the middle segment 303b can increase the area of the first graphic 305, so the embodiment of the present invention can increase the area of the first graphic 305 under the condition that the corner-to-corner spacing d302 does not violate the MRC .

The increase in the area of the first pattern 305 can increase the area of the corresponding exposure pattern, so that the exposure pattern meets the target value, ie on-target. As shown in FIG. 4D , the outline graphic 306 is a schematic diagram of a simulation diagram of the exposure graphic corresponding to the first graphic 305 . Compared with the outline graphic 205 in FIG. 2B , it can be seen that the area of the outline graphic 306 obtained in the embodiment of the present invention is larger. , which is closer to the corresponding target graph, eliminating the off-target defect corresponding to Figure 2B.

However, in the prior art, before MBOPC, the edge of the first graphic 302 is not segmented, so in MBOPC, when the corner-to-corner spacing of the first graphic 302 is restricted by violating the MRC and the iterative cycle operation is stopped, the first graphic The area of 302 will be kept small, and finally the contour figure of the first figure 302 after MBOPC, that is, the simulation figure of the exposure figure, will deviate from the target value; after the initial target layer 301 is provided, the embodiment of the present invention is not directly based on the initial target layer 301 perform model-based OPC correction, but pre-select according to the characteristics of the graphics in the initial target layer 301, the first graphics 302 that violate the MRC will appear in the model-based OPC correction, and then segment these selected graphics Process and form the second target layer 301a, then carry out MBOPC, after each side of the first graphic 302 has been segmented, the corner segment 303a and the middle segment 303b can be corrected separately in each iterative cycle operation of MBOPC, so that The size of the top corner of the first figure 302 and the size of the middle area can be adjusted separately. By adjusting the size of the top corner of the first figure 302, the corner-to-corner spacing of the first figure 302 can not violate the MRC; The size adjustment of the region can adjust the area of the first graphic 302, so that the area of the first graphic 302 can be increased when the corner-to-corner spacing of the first graphic 302 meets the requirements of the MRC, and the increase of the area of the first graphic 302 after MBOPC can make The contour graphics conform to the target value, so that the real exposed graphics will also be ontarget.

The embodiment of the present invention is particularly applicable to the OPC correction of square patterns with a dense staggered structure, such as through-hole layer patterns, and can realize the size of the square pattern in the mask layer 304, and can expose the pattern without violating the mask MRC. The corresponding simulation contour is not only on-target, but also the pvband and meef under PW conditions meet the mass production requirements.

As shown in Figure 5A, it is a simulation diagram of the mask layer and contour graphics formed by the existing OPC correction method; the mask layer 401a includes a mask graphic 403a corrected by MBOPC to the target graphic 402, and the target graphic 402 Corresponding to the pattern 202 in FIG. 2A, the mask pattern 403a corresponds to the pattern 204 in FIG. 2B. The existing method is also equivalent to the size of the angular segment in the method of the embodiment of the present invention being 0 nm, that is, Split 0 nm. The contour pattern 404a is a simulation diagram of the exposure pattern corresponding to the mask pattern 403a. It can be seen that the contour pattern 404a is quite different from the target pattern 402 and is in an off-target state.

FIG. 5B is a simulation diagram of the mask layer and contour graphics formed when the corner segment size is 5nm in the OPC correction method of the method of the embodiment of the present invention; the mask layer 401b includes a mask corrected by MBOPC on the target pattern 402 Graph 403b, the target graph 402 corresponds to the graph 302 in FIG. 4A, which is the same as the target graph 402 in FIG. 5A, that is, different MBOPC corrections are made to the corresponding target graph 402 to compare the correction results. The contour pattern 404b is a simulation diagram of the exposure pattern corresponding to the mask pattern 403b; the size of the angular segment in FIG. 5B is 5nm, that is, Split 5nm. It can be seen that the outline graphic 404b is close to the target graphic 402 and is in an on-target state.

FIG. 5C is a simulation diagram of the mask layer and contour graphics formed when the corner segment size is 10nm in the OPC correction method of the method of the embodiment of the present invention; the mask layer 401c includes a mask corrected by MBOPC on the target pattern 402 The graph 403c, the target graph 402 corresponds to the graph 302 in FIG. 4A. The contour pattern 404c is a simulation diagram of the exposure pattern corresponding to the mask pattern 403c; the size of the angular segment in FIG. 5C is 10nm, that is, Split 10nm. It can be seen that the outline graphic 404c is close to the target graphic 402 and is in an on-target state.

FIG. 5D is a simulation diagram of the mask layer and contour graphics formed when the corner segment size is 15nm in the OPC correction method of the method of the embodiment of the present invention; the mask layer 401d includes a mask corrected by MBOPC on the target pattern 402 The graph 403d, the target graph 402 corresponds to the graph 302 in FIG. 4A. The contour pattern 404d is a simulation diagram of the exposure pattern corresponding to the mask pattern 403d; the size of the angular segment in FIG. 5D is 15nm, that is, Split 15nm. It can be seen that the outline graphic 404d is close to the target graphic 402 and is in an on-target state.

FIG. 5E is a simulation diagram of a mask layer and contour graphics formed when the corner segment size is 20nm in the OPC correction method of the method of the embodiment of the present invention. The mask layer 401e includes a mask pattern 403e corrected by MBOPC on the target pattern 402, and the target pattern 402 corresponds to the pattern 302 in FIG. 4A. The contour pattern 404e is a simulation diagram of the exposure pattern corresponding to the mask pattern 403e; the size of the angular segment in FIG. 5E is 20nm, that is, Split 20nm. It can be seen that the outline graphic 404e is close to the target graphic 402 and is in the on-target state.

The test data corresponding to Figure 5A to Figure 5E is shown in Table 1:

Table I

Among them, the split size corresponding to the existing method, that is, the size of the corner segment, is 0 nm, and the segment processing is listed according to the different split sizes, namely 5 nm, 10 nm, 15 nm and 20 nm.

In the test result, Target represents the key size of the target graphic 402;

Mask Space indicates the spacing of the mask graphics;

Mask CD indicates the critical dimension of the mask pattern;

Mask Area indicates the area of the mask pattern.

Contour represents the key dimension of contour graphics.

PW_minCD represents the minimum critical dimension of the process window.

Pvband represents the process variation band.

Meef stands for Mask Error Enhancement Factor.

It can be seen that under the condition that the Mask Space does not violate the MRC, the Mask CD corresponding to the embodiment of the present invention will increase, the Mask Area will increase, the key size of the Contour will increase, the PW_minCD will increase, the Pvband will decrease, and the Meef will decrease. All indicate that the OPC correction result of the method of the embodiment of the present invention is better.

The present invention has been described in detail through specific examples above, but these do not constitute a limitation to the present invention. Without departing from the principle of the present invention, those skilled in the art can also make many modifications and improvements, which should also be regarded as the protection scope of the present invention.

Claims (13)

1. An OPC correction method, characterized by comprising the steps of:

step one, providing an initial target layer and setting the minimum analysis size of a mask plate;

selecting a first graph which can violate mask rule check in the follow-up OPC correction based on a model from the initial target layer according to the minimum analysis size of the mask plate;

step three, carrying out segmentation processing on the first graph, wherein the segmentation processing divides each side of the first graph into a plurality of segments, each segment of each side comprises an angle segment and a middle segment, one vertex of the angle segment is the vertex of the side, and the other vertex of the angle segment is the vertex of the adjacent middle segment; the initial target layer after the segmentation processing is a second target layer;

and fourthly, performing model-based OPC correction based on the second target layer and obtaining a mask plate layer, wherein the model-based OPC correction comprises a plurality of iterative loop operations, in each iterative loop operation, the corner segments and the middle segments of the sides of the first graph are corrected separately, the vertex angle size of the first graph in the mask plate layer is controlled through the corner segments, and the area of the first graph in the mask plate layer is controlled through the middle segments.

2. The OPC correction method of claim 1 wherein: after the fourth step, the method further comprises:

and fifthly, performing mask rule inspection on the mask plate layer.

3. The OPC correction method of claim 1 wherein: in the first step, the initial target layer is obtained by performing rule-based OPC correction on the initial layout.

4. The OPC correction method of claim 2 wherein: the minimum resolution of the mask plate comprises a minimum resolution value of a key size and a minimum resolution value of a space.

5. The OPC correction method of claim 4 wherein: and step five, checking and passing the mask rule when the critical dimension of the first pattern in the mask plate layer is larger than the minimum analytic value of the critical dimension and the distance is larger than the minimum analytic value of the distance.

6. The OPC correction method of claim 4 wherein: the first pattern includes a square hole pattern.

7. The OPC correction method of claim 6 wherein: the square hole pattern includes a through hole layer pattern.

8. The OPC correction method of claim 7 wherein: in the initial target layer, an array structure formed by arranging the first patterns is a compact staggered structure, diagonal lines of the first patterns are aligned and are arranged periodically in the compact staggered structure, the minimum distance of the first patterns is the distance between adjacent vertex angles of two adjacent first patterns, and the step of the first patterns is the sum of the length of the diagonal lines of the first patterns and the minimum distance.

9. The OPC correction method of claim 8 wherein: the minimum reticle resolution size is determined by the process node and reticle fabrication capability.

10. The OPC correction method of claim 9 wherein: the process node is below 14nm, and the critical dimension minimum resolution and the pitch minimum resolution are both 18nm or both 12nm.

11. The OPC correction method of claim 10 wherein: the minimum pitch of the first pattern is less than 20nm, and the step of the first pattern is less than 115nm.

12. The OPC correction method of claim 10 wherein: the target value of the side length of the first pattern is 68nm, and the angular segment size in the segmentation process is 5-20nm.

13. The OPC correction method of claim 8 wherein: in step three, the segmentation process segments each of the edges of the first graph into 3 segments, the 3 segments including two of the corner segments and one of the intermediate segments.