OPC Correction Method

Abstract

This invention discloses an OPC correction method, comprising: Step 1, providing an original layout, wherein the original layout contains a transition area between dense graphics and isolated graphics, and in the transition area there are two or more semi-isolated line ends aligned with an alignment line. Step 2, finding all alignment lines and the corresponding semi-isolated line ends. Step 3, performing pre-adjustment of the semi-isolated line ends, including: lengthening or shortening to adjust the side position of the semi-isolated line ends, so that there is a first gap between the sides of two adjacent semi-isolated line ends aligned with the alignment line, thereby increasing the process window for OPC correction of dense graphics adjacent to the semi-isolated line ends; the original layout becomes an intermediate layout after the semi-isolated line end adjustment. Step 4, performing OPC correction on the intermediate layout. This invention can improve the process window for OPC correction of dense graphics adjacent to the alignment position of semi-isolated line ends.

Description

TECHNICAL FIELD

[0001] The present application relates to a semiconductor integrated circuit manufacturing method, in particular to an optical proximity effect correction (OPC) method. BACKGROUND

[0002] In a photolithography process, the pattern structure on a mask corresponds to the pattern structure formed in a photoresist by an exposure system. However, due to optical reasons in the exposure process or chemical reaction of the photoresist, the pattern structure formed in the photoresist is different from the pattern structure on the mask. The difference needs to be corrected by OPC, and the pattern structure formed in the photoresist by using the mask corrected by OPC will be consistent with the designed pattern structure and meet the process production requirements.

[0003] In the pattern structure, the pattern structure is divided into dense patterns, isolated patterns and semi-isolated patterns in the transition region between the two according to the pattern density. The distance between the dense patterns is reduced, and the diffraction light between the dense patterns interacts with each other in the photolithography process. The side of the isolated pattern is relatively empty, and the diffraction light between the isolated patterns has weak or no interaction. The semi-isolated pattern has dense pattern region on one side and relatively empty region on the other side.

[0004] The pattern includes multiple pattern layers, such as a metal layer and a via layer. For the metal layer, especially in the process close to the lithography limit, the process window difference is prone to occur in the transition region between the dense / isolated patterns. At this time, methods such as pitch loose and via shift are often used to prevent line breakage. FIG. 1A As shown in FIG. 1, a schematic diagram of dense patterns before pitch loose in the transition region is shown before OPC correction in the prior art OPC correction method. FIG. 1A As shown in FIG. 1, a schematic diagram of dense patterns before pitch loose in the transition region is shown before OPC correction in the prior art OPC correction method.

[0005] As shown in FIG. 2, a schematic diagram of dense patterns after pitch loose in the transition region is shown after OPC correction in the prior art OPC correction method. The pattern space period of the metal layer pattern 101 is the sum of the width w101a and the pitch w102a. w101a is greater than w101, and w102a is greater than w102. FIG. 1B As shown in FIG. 2, a schematic diagram of dense patterns after pitch loose in the transition region is shown after OPC correction in the prior art OPC correction method. The pattern space period of the metal layer pattern 101 is the sum of the width w101a and the pitch w102a. w101a is greater than w101, and w102a is greater than w102.

[0006] But in the case of multiple quasi-isolated line ends, i.e. half-isolated line ends, aligning to a line, due to the optical / photo-resist phenomenon of line end shortening, the line ends need to be largely corrected outwardly, and the aligned line ends will produce simultaneous outward expansion and mutual conflict in OPC correction, thus causing serious squeezing from both sides to the middle dense pattern area, and the pitch loose cannot completely solve the problem of the middle area process window difference and easy line breaking. SUMMARY

[0007] The technical problem to be solved by the present application is to provide an OPC correction method, which can improve the process window of OPC correction of dense patterns near the alignment position of half-isolated line ends.

[0008] To solve the above technical problem, the present application provides an OPC correction method, which comprises the following steps:

[0009] Step one, providing an original layout needing OPC correction, wherein a transition area of dense patterns and isolated patterns exists, and multiple half-isolated line ends exist in the transition area, and each half-isolated line end is adjacent to the corresponding dense pattern.

[0010] In the transition area, two or more half-isolated line ends align to a straight alignment line, and the length direction of the half-isolated line end is perpendicular to the straight alignment line.

[0011] Step two, finding all the straight alignment lines and the corresponding half-isolated line ends of each straight alignment line in the original layout.

[0012] Step three, performing pre-adjustment of the half-isolated line ends, including: extending or shortening along the length extension direction of the corresponding half-isolated line end to adjust the side surface position of the half-isolated line end, so that the side surfaces of two adjacent half-isolated line ends aligning to the straight alignment line have a first interval, and the process window of OPC correction of the dense pattern adjacent to the half-isolated line end is increased by increasing the first interval; and the original layout after adjustment of the half-isolated line ends becomes an intermediate layout.

[0013] Step four, performing OPC correction on the intermediate layout.

[0014] Further improvement is that the original layout includes metal layer patterns, and the dense patterns, the isolated patterns and the half-isolated line ends are all metal layer patterns.

[0015] Further improvement is that in the dense pattern area, each dense pattern has a strip structure, and each dense pattern is periodically arranged in the width direction.

[0016] Further improvement is that the first interval is large enough to ensure that the OPC correction at the side of the two adjacent half-isolated line ends does not affect the OPC correction of the adjacent dense pattern.

[0017] Further improvement is that the first interval is larger than the pitch of the dense pattern.

[0018] Further improvement is that the transition region exists on both sides of the dense pattern region along the width direction of the dense pattern.

[0019] Further improvement is that the half-isolated line ends aligned with the alignment straight line are located in the transition region on the same side of the dense pattern region.

[0020] Further improvement is that in the original layout, the two adjacent half-isolated line ends extend in opposite directions, partially overlap or have an interval, and the interval between the sides of the two adjacent half-isolated line ends is less than or equal to a second interval, which makes the sides of the half-isolated line ends nearly aligned, so that the OPC correction at the sides of the two adjacent half-isolated line ends affects the OPC correction of the adjacent dense pattern.

[0021] Further improvement is that the half-isolated line ends aligned with the alignment straight line are located in the transition region on opposite sides of the dense pattern region.

[0022] Further improvement is that in the original layout, the two adjacent half-isolated line ends extend in opposite directions, partially overlap, and the interval between the sides of the two adjacent half-isolated line ends is less than or equal to a second interval, which makes the sides of the half-isolated line ends nearly aligned, so that the OPC correction at the sides of the two adjacent half-isolated line ends affects the OPC correction of the adjacent dense pattern.

[0023] Alternatively, the two adjacent half-isolated line ends extend in the same direction, the interval between the sides of the two adjacent half-isolated line ends is less than or equal to a second interval, which makes the sides of the half-isolated line ends nearly aligned, so that the OPC correction at the sides of the two adjacent half-isolated line ends affects the OPC correction of the adjacent dense pattern.

[0024] Further improvement is that in step three, the first interval is adjusted by elongating one or both of the two adjacent half-isolated line ends; or, the first interval is adjusted by shortening one or both of the two adjacent half-isolated line ends.

[0025] Further improvement is that in step three, when elongating the corresponding half-isolated line end along the length extension direction, it is required to ensure that the interval between the side surface of the elongated half-isolated line end and the adjacent pattern in the extension direction of the half-isolated line end meets the requirement; when the interval between the side surface of the elongated half-isolated line end and the adjacent pattern in the extension direction of the half-isolated line end does not meet the requirement, the adjacent pattern in the extension direction of the half-isolated line end is retreated along the length extension direction of the half-isolated line end.

[0026] Further improvement is that the original layout further includes a via layer pattern; the via layer pattern is located on the selected area of the metal layer pattern.

[0027] Further improvement is that in step three, when shortening the corresponding half-isolated line end along the length extension direction, it is required to ensure that the interval between the side surface of the shortened half-isolated line end and the adjacent via layer pattern meets the requirement.

[0028] Further improvement is that when elongating the corresponding half-isolated line end along the length extension direction, the extension part of the half-isolated line end serves as an auxiliary pattern.

[0029] Further improvement is that in step four, before the OPC correction, the dense pattern adjacent to each half-isolated line end is step-loosened.

[0030] The present application finds all alignment straight lines in the transition area and each half-isolated line end aligned with the corresponding alignment straight line before the OPC correction of the original layout, elongates or shortens each half-isolated line end to adjust the first interval between the side surfaces of two adjacent half-isolated line ends aligned with the alignment straight line, and increases the first interval, so that the influence of the two half-isolated line ends on the adjacent dense pattern is staggered in the OPC correction, thereby increasing the process window of the OPC correction of the dense pattern adjacent to the half-isolated line end, and preventing the problem of easy breaking line caused by the poor process window.

[0031] The present application is particularly suitable for the OPC correction of the metal layer, and improves the process window of the OPC correction of the metal layer.

[0032] The auxiliary pattern can be sacrificed if necessary, and can avoid the adverse effect on the main pattern when the extension part is introduced. BRIEF DESCRIPTION OF DRAWINGS

[0033] The application will be further described in detail below in combination with the drawings and specific embodiments:

[0034] FIGS. 1A-1B is a schematic diagram of the dense pattern before and after the space period of the dense pattern near the transition region is loosened in the prior OPC correction method before OPC correction;

[0035] FIG. 2 is a flow chart of the OPC correction method of the embodiment of the application;

[0036] FIGS. 3A-3D is a schematic diagram of the alignment of various semi-isolated line ends in the original layout of the OPC correction method of the embodiment of the application;

[0037] FIGS. 4A-4C is a schematic diagram of the pre-adjustment of various semi-isolated line ends in the OPC correction method of the embodiment of the application by using the elongation method;

[0038] FIGS. 5A-5C is a schematic diagram of the pre-adjustment of various semi-isolated line ends in the OPC correction method of the embodiment of the application by using the shortening method. DETAILED DESCRIPTION

[0039] As shown in FIG. 2 , it is a flow chart of the OPC correction method of the embodiment of the application; as shown in FIGS. 3A-3D , it is a schematic diagram of the alignment of various semi-isolated line ends 202 in the original layout of the OPC correction method of the embodiment of the application; as shown in FIGS. 4A-4C , it is a schematic diagram of the pre-adjustment of various semi-isolated line ends 202 in the OPC correction method of the embodiment of the application by using the elongation method; as shown in FIGS. 5A-5C , it is a schematic diagram of the pre-adjustment of various semi-isolated line ends 202 in the OPC correction method of the embodiment of the application by using the shortening method; the OPC correction method of the embodiment of the application comprises the following steps:

[0040] Step one, as shown in FIGS. 3A-3D , it is a schematic diagram of the alignment of various semi-isolated line ends 202 in the original layout of the OPC correction method of the embodiment of the application; the original layout needing OPC correction is provided, the original layout has a transition region of dense pattern 201 and isolated pattern (not shown), and there are multiple semi-isolated line ends 202 in the transition region, and each semi-isolated line end 202 is adjacent to the corresponding dense pattern 201.

[0041] In the transition region, there are two or more structures in which the semi-isolated line ends 202 are aligned with the alignment line 203, and the alignment line 203 is perpendicular to the length direction of the semi-isolated line ends 202.

[0042] In this embodiment of the invention, the original layout includes a metal layer pattern, and the dense pattern 201, the isolated pattern, and the semi-isolated line end 202 are all metal layer patterns.

[0043] The original layout also includes a via layer pattern; the via layer pattern is located on a selected area of ​​the metal layer pattern.

[0044] In the dense pattern 201 region, each of the dense patterns 201 has a strip structure and each of the dense patterns 201 is periodically arranged along the width direction.

[0045] Along the width direction of the dense pattern 201, there are transition regions on both sides of the dense pattern 201 region.

[0046] The semi-isolated line ends 202 aligned with the alignment line 203 are all located in the transition region on the same side of the dense pattern 201 region. FIG. 3A and FIG. 3B The figures shown all correspond to this situation.

[0047] The lengths of two adjacent semi-isolated line ends 202 extend in opposite directions. Ideally, the two adjacent semi-isolated line ends 202 would be perfectly aligned, but in reality, they would have the following characteristics: FIG. 3A The partial overlap shown or having the following characteristics FIG. 3B The spacing shown is such that the distance between the sides of two adjacent semi-isolated line ends 202 is less than or equal to a second distance, which makes the sides of the semi-isolated line ends 202 nearly aligned. This causes the influence areas of OPC corrections on the sides of two adjacent semi-isolated line ends 202 on the OPC corrections of adjacent dense patterns 201 to overlap, as shown in the area marked 204. This overlap affects the process window of the OPC correction for adjacent dense patterns 201. That is, when performing OPC corrections, each pattern often requires a certain amount of space to change; in the area marked 204, the OPC correction space of the dense pattern 201 is simultaneously affected by the corrections of the two semi-isolated line ends 202, thus reducing the OPC correction space of the dense pattern 201, i.e., reducing the process window.

[0048] The semi-isolated line end 202, which is aligned with the alignment line 203, is located in the transition region on opposite sides of the dense pattern 201 region. FIG. 3C and FIG. 3DThe shown graphs all correspond to this case.

[0049] FIG. 3C The shown graph further includes: in the original layout, the length extension directions of two adjacent half-isolated line ends 202 are opposite, two adjacent half-isolated line ends 202 partially overlap, the spacing between the side faces of two adjacent half-isolated line ends 202 is less than or equal to a second spacing, the second spacing makes the side faces of the half-isolated line ends 202 nearly aligned, so that the influence areas of the OPC corrections at the side faces of two adjacent half-isolated line ends 202 overlap, thereby affecting the process window of the OPC correction of the adjacent dense pattern 201.

[0050] FIG. 3D The shown graph further includes: the length extension directions of two adjacent half-isolated line ends 202 are the same, the spacing between the side faces of two adjacent half-isolated line ends 202 is less than or equal to a second spacing, the second spacing makes the side faces of the half-isolated line ends 202 nearly aligned, so that the influence areas of the OPC corrections at the side faces of two adjacent half-isolated line ends 202 overlap, thereby affecting the process window of the OPC correction of the adjacent dense pattern 201.

[0051] Step two, find all the aligned straight lines 203 and the corresponding half-isolated line ends 202 in the original layout, that is, find the half-isolated line ends 202 corresponding to the aligned straight lines 203 as shown in the following table. FIGS. 3A-3D The aligned straight lines 203 and the corresponding half-isolated line ends 202 in the four cases shown in the table.

[0052] Step three, pre-adjust the half-isolated line ends 202, including: elongating or shortening along the length extension direction of the corresponding half-isolated line end 202 to adjust the side face position of the half-isolated line end 202, so that the spacing between the side faces of two adjacent half-isolated line ends 202 aligned with the aligned straight line 203 is a first spacing d201, and the process window of the OPC correction of the dense pattern 201 adjacent to the half-isolated line end 202 is increased by increasing the first spacing d201; the original layout becomes an intermediate layout after the adjustment of the half-isolated line ends 202.

[0053] In the embodiment of the present application, the size of the first spacing d201 ensures that the influence areas of the OPC corrections at the side faces of two adjacent half-isolated line ends 202 are completely staggered. In some preferred embodiments, the first spacing d201 is greater than or equal to the pitch of the dense pattern 201. Taking the pitch of the dense pattern 201 as 80 nm as an example, the first spacing d201 can be taken as 100 nm.

[0054] In some embodiments, the first distance d201 is adjusted by elongating one or both of the two adjacent half-isolated line ends 202. The pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2A is described as follows: FIGS. 3A-3D The pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2A is described as follows: As shown in FIG. 2B, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2B.

[0055] As shown in FIG. 2C, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2C. FIG. 4A As shown in FIG. 2D, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2D. FIG. 4A As shown in FIG. 2E, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2E. FIG. 3A As shown in FIG. 2F, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2F. FIG. 3B As shown in FIG. 2G, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2G. FIG. 4A As shown in FIG. 2H, both of the two adjacent half-isolated line ends 202 are elongated, and the elongated portions are marked with reference numeral 202a. After the pre-adjustment, the sides of the two adjacent half-isolated line ends 202 and the center of the region shown by reference numeral 204 are misaligned, thereby eliminating the overlapping influence of the sides of the two adjacent half-isolated line ends 202 on the region shown by reference numeral 204.

[0056] As shown in FIG. 2I, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2I. FIG. 4B As shown in FIG. 2J, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2J. FIG. 4B As shown in FIG. 2K, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2K. FIG. 3C As shown in FIG. 2L, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2L. FIG. 4B As shown in FIG. 2M, one of the two adjacent half-isolated line ends 202 is elongated, and the other is fixed, and the elongated portion is marked with reference numeral 202a. After the pre-adjustment, the distance between the sides of the two adjacent half-isolated line ends 202 is large, thereby eliminating the overlapping influence of the sides of the two adjacent half-isolated line ends 202 on the region shown by reference numeral 204.

[0057] As shown in FIG. 2N, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2N. FIG. 4C As shown in FIG. 2O, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2O. FIG. 4C As shown in FIG. 2P, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2P. FIG. 3D As shown in FIG. 2Q, the pre-adjustment shown in FIG. 2A is applicable to the pre-adjustment of the half-isolated line ends 202 in the pattern shown in FIG. 2Q. FIG. 4C As shown in FIG. 2R, one of the two adjacent half-isolated line ends 202 is elongated, and the other is fixed, and the elongated portion is marked with reference numeral 202a. After the pre-adjustment, the distance between the sides of the two adjacent half-isolated line ends 202 is large, thereby eliminating the overlapping influence of the sides of the two adjacent half-isolated line ends 202 on the region shown by reference numeral 204.

[0058] In some embodiments, when the corresponding half isolated line end 202 is elongated along the length extension direction, it is necessary to ensure that the spacing between the side surface of the elongated half isolated line end 202 and the adjacent pattern in the extension direction of the half isolated line end 202 meets the requirements; when the spacing between the side surface of the elongated half isolated line end 202 and the adjacent pattern in the extension direction of the half isolated line end 202 does not meet the requirements, the adjacent pattern in the extension direction of the half isolated line end 202 can be retreated along the length extension direction of the half isolated line end 202 when the condition permits.

[0059] The elongated part 202a of the half isolated line end 202 can be treated as an auxiliary pattern because it does not have a relationship with the via layer pattern, and can be appropriately sacrificed when necessary to allow it to be disconnected, thereby leaving sufficient modification space for the nearby pattern.

[0060] In other embodiments, the first spacing d201 is adjusted by shortening one or both of the two adjacent half isolated line ends 202. The pre-adjustment of the half isolated line end 202 in the pattern shown in FIG. 8A is described as follows: FIGS. 3A-3D The pre-adjustment shown in FIG. 8A is applicable to the pre-adjustment of the half isolated line end 202 in the pattern shown in FIG. 8B,

[0061] As shown in FIG. 8B, FIG. 5A As shown in FIG. 8B, FIG. 5A The pre-adjustment shown in FIG. 8B is applicable to the pre-adjustment of the half isolated line end 202 in the pattern shown in FIG. 8C, FIG. 3A and FIG. 3B The pre-adjustment shown in FIG. 8B is applicable to the pre-adjustment of the half isolated line end 202 in the pattern shown in FIG. 8C, FIG. 5A In FIG. 8C, both of the two adjacent half isolated line ends 202 are shortened, and the shortened part is marked with a mark 202b. As can be seen, after the pre-adjustment, the side surfaces of the two adjacent half isolated line ends 202 and the center of the region shown by the mark 204 will be misaligned, thereby eliminating the overlapping influence of the side surfaces of the two adjacent half isolated line ends 202 on the region shown by the mark 204.

[0062] As shown in FIG. 8D, FIG. 5B As shown in FIG. 8D, FIG. 5B The pre-adjustment shown in FIG. 8D is applicable to the pre-adjustment of the half isolated line end 202 in the pattern shown in FIG. 8E, FIG. 3C The pre-adjustment shown in FIG. 8D is applicable to the pre-adjustment of the half isolated line end 202 in the pattern shown in FIG. 8E, FIG. 5B In FIG. 8E, both of the two adjacent half isolated line ends 202 are shortened, and the shortened part is marked with a mark 202b. As can be seen, after the pre-adjustment, the side surfaces of the two adjacent half isolated line ends 202 and the center of the region shown by the mark 204 will be misaligned, thereby eliminating the overlapping influence of the side surfaces of the two adjacent half isolated line ends 202 on the region shown by the mark 204.

[0063] AsFIG. 5C as shown, FIG. 5C The pre-adjustment shown is applicable to the adjustment of FIG. 3D the pre-adjustment of the half-isolated line end 202 in the pattern, FIG. 5C In the above, one of the two adjacent half-isolated line ends 202 is shortened, and the other is fixed, and the elongated part is marked as 202b. After the pre-adjustment, the distance between the side surfaces of the two adjacent half-isolated line ends 202 is larger, and the overlapping of the side surfaces of the two adjacent half-isolated line ends 202 on the area marked as 204 is eliminated.

[0064] In some embodiments, when the corresponding half-isolated line end 202 is shortened in the length extension direction, it is necessary to ensure that the distance between the side surface of the shortened half-isolated line end 202 and the adjacent via layer pattern meets the requirements.

[0065] Since FIGS. 3A-3D The pattern structure shown can be located in different area positions of the same original layout, so the embodiments of the present application can select FIGS. 4A-4C the elongation mode in the above or FIGS. 5A-5C FIGS. 3A-3D the shortening mode in the above to perform the pre-adjustment according to the actual pattern structure of different areas of the original layout. For example, when there is no space in the elongation direction of the half-isolated line end 202, the pre-adjustment of the shortening mode can be adopted.

[0066] Step four, performing OPC correction on the intermediate layout.

[0067] In some embodiments, before the OPC correction, the dense pattern 201 near each half-isolated line end 202 is further subjected to step-by-step relaxation, such as relaxation of the dense metal layer pattern and displacement of the via layer pattern at the same time. In this way, the OPC correction process window of the dense pattern 201 near each half-isolated line end 202 can be further increased.

[0068] The embodiments of the present application find all alignment straight lines 203 in the transition area and each half-isolated line end 202 aligned with the corresponding alignment straight line 203 before performing OPC correction on the original layout, elongate or shorten each half-isolated line end 202 to adjust the distance between the side surfaces of two adjacent half-isolated line ends 202 aligned with the alignment straight line 203 to have a first distance d201, and use the first distance d201 to increase the distance. In the OPC correction, the influence of the two half-isolated line ends 202 on the adjacent dense pattern 201 will be staggered, so that the process window of the OPC correction of the dense pattern 201 near the half-isolated line end 202 can be increased, and the problem of easy breaking line due to poor process window can be prevented.

[0069] The dense patterns 201 near each of the semi-isolated line ends 202 are particularly suitable for OPC correction of the metal layer, and improve the process window of OPC correction of the metal layer.

[0070] The dense patterns 201 near each of the semi-isolated line ends 202 can also employ auxiliary patterns in the extension part of the elongation of the semi-isolated line ends 202, which can be sacrificed if necessary, so that adverse effects on the main patterns can be avoided when the extension part is introduced.

[0071] The beneficial effects of the method of the embodiments of the present application relative to the prior art method can be more clearly understood by comparing the following experiments:

[0072] The 1.25x metal minimum design size of 14HF is 40nm / 40nm, which is close to the lithography limit of a 193nm light source. In a complex layout in a logic area, there are a large number of dense / isolated pattern transition regions and multiple semi-isolated line ends that are collinear, and the results are as follows:

[0073] If the correction script only employs the pitch loose operation, the minimum nils of the post-OPC verification of the entire layout is 0.76, and the minimum CD within the process window (dose 0.96-1.04, focus ±40nm) is 40.2nm.

[0074] If the correction script performs the pre-adjustment optimization operation of the embodiments of the present application before the pitch loose, the minimum nils of the post-OPC verification of the entire layout is 0.84, and the minimum CD within the process window (dose 0.96-1.04, focus ±40nm) is 40.7nm.

[0075] The present application has been described in detail by specific embodiments, but these do not constitute a limitation on the present application. Those skilled in the art can make many modifications and improvements without departing from the principles of the present application, and these should also be considered as within the scope of protection of the present application.

Claims

1. An OPC correction method characterized by, The method comprises the following steps: Step 1: providing an original layout which needs to be corrected by OPC, the original layout has a transition area between dense patterns and isolated patterns, and a plurality of half-isolated line ends exist in the transition area, and each half-isolated line end is adjacent to the corresponding dense pattern; In the transition area, two or more half-isolated line ends are aligned on an alignment straight line, and the alignment straight line is perpendicular to the length direction of the half-isolated line end; Step 2: finding all the alignment straight lines and the corresponding half-isolated line ends of each alignment straight line in the original layout; Step 3: pre-adjusting the half-isolated line end, including: extending or shortening along the length extension direction of the corresponding half-isolated line end to adjust the side position of the half-isolated line end, so that the first interval between the sides of two adjacent half-isolated line ends aligned on the alignment straight line is obtained, and the process window of OPC correction of the dense pattern adjacent to the half-isolated line end is increased by increasing the first interval; and the original layout becomes an intermediate layout after the half-isolated line end is adjusted; Step 4: correcting the intermediate layout by OPC; The original layout includes metal layer patterns, and the dense patterns, the isolated patterns and the half-isolated line ends are all metal layer patterns; In the dense pattern area, each dense pattern has a strip structure, and each dense pattern is periodically arranged along the width direction.

2. The OPC correction method of claim 1, wherein: The size of the first interval ensures that the influence areas of OPC correction at the sides of the two adjacent half-isolated line ends are completely staggered.

3. The OPC correction method of claim 2, wherein: The first interval is greater than or equal to the step of the dense pattern.

4. The OPC correction method of claim 1, wherein: On both sides of the dense pattern area along the width direction of the dense pattern, the transition area exists.

5. The OPC correction method of claim 4, wherein: The half-isolated line ends aligned with the alignment straight line are located in the transition area on the same side of the dense pattern area.

6. The OPC correction method of claim 5, wherein: In the original layout, the length extension directions of two adjacent half-isolated line ends are opposite, the two adjacent half-isolated line ends partially overlap or have an interval, and the interval between the sides of the two adjacent half-isolated line ends is less than or equal to a second interval, the second interval makes the sides of the half-isolated line ends nearly aligned, so that the influence areas of OPC correction at the sides of the two adjacent half-isolated line ends overlap, thereby affecting the process window of OPC correction of the adjacent dense pattern.

7. The OPC correction method of claim 4, wherein: The half-isolated line ends aligned with the alignment straight line are located in the transition area on opposite sides of the dense pattern area.

8. The OPC correction method of claim 5, wherein: In the original layout, the length extension directions of two adjacent half-isolated line ends are opposite, the two adjacent half-isolated line ends partially overlap, and the interval between the sides of the two adjacent half-isolated line ends is less than or equal to a second interval, the second interval makes the sides of the half-isolated line ends nearly aligned, so that the influence areas of OPC correction at the sides of the two adjacent half-isolated line ends overlap, thereby affecting the process window of OPC correction of the adjacent dense pattern. Alternatively, the length extension directions of the two adjacent half-isolated line ends are the same, and the distance between the side surfaces of the two adjacent half-isolated line ends is less than or equal to a second distance, the second distance is such that the side surfaces of the two adjacent half-isolated line ends are close to alignment, so that the OPC correction at the side surfaces of the two adjacent half-isolated line ends overlaps the influence area of the OPC correction of the adjacent dense pattern, thereby affecting the process window of the OPC correction of the adjacent dense pattern.

9. The OPC correction method of claim 1, wherein: In step three, the first distance is adjusted by elongating one or both of the two adjacent half-isolated line ends; or the first distance is adjusted by shortening one or both of the two adjacent half-isolated line ends.

10. The OPC correction method of claim 9, wherein: In step three, when the corresponding half-isolated line end is elongated in the length extension direction, it is necessary to ensure that the distance between the side surface of the elongated half-isolated line end and the adjacent pattern in the extension direction of the half-isolated line end meets the requirements; when the distance between the side surface of the elongated half-isolated line end and the adjacent pattern in the extension direction of the half-isolated line end does not meet the requirements, the adjacent pattern in the extension direction of the half-isolated line end is retreated in the length extension direction of the half-isolated line end.

11. The OPC correction method of claim 1, wherein: The original layout further includes a via layer pattern; the via layer pattern is located on a selected region of the metal layer pattern.

12. The OPC correction method of claim 11, wherein: In step three, when the corresponding half-isolated line end is shortened in the length extension direction, it is necessary to ensure that the distance between the side surface of the shortened half-isolated line end and the adjacent via layer pattern meets the requirements.

13. The OPC correction method of claim 9, wherein: When the corresponding half-isolated line end is elongated in the length extension direction, the extended part of the half-isolated line end serves as an auxiliary pattern.

14. The OPC correction method of claim 1, wherein: In step four, before the OPC correction is performed, the dense pattern adjacent to each half-isolated line end is further subjected to stepwise relaxation.

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