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CN-116413993-B - Optical proximity correction method

CN116413993BCN 116413993 BCN116413993 BCN 116413993BCN-116413993-B

Abstract

An optical proximity correction method comprises the steps of providing a correction layout comprising a plurality of correction patterns, acquiring an exposure layout comprising a plurality of first exposure patterns according to the correction layout, acquiring a plurality of sampling points on the outline of the first exposure patterns by adopting a plurality of sampling steps to form sampling patterns, acquiring an ith sampling point on the outline of the first exposure patterns, acquiring an L position point on the correction pattern corresponding to the first exposure patterns, wherein the L position point corresponds to the ith sampling point, acquiring the curvature of the ith sampling point, acquiring a first offset between the ith sampling point and the L position point, acquiring a second offset between the L-1 position point and the L position point of the correction pattern, wherein the L-1 position point corresponds to the ith-1 sampling point, acquiring an i+1 sampling step length according to the curvature of the ith sampling point, the first offset and the second offset, and acquiring an i+1 sampling point on the first exposure pattern according to the i+1 sampling step length. The method improves the prediction precision.

Inventors

  • NI CHANG
  • HAO WENQIN

Assignees

  • 中芯国际集成电路制造(上海)有限公司

Dates

Publication Date
20260508
Application Date
20211231

Claims (7)

  1. 1. An optical proximity correction method, comprising: Providing a corrected layout, wherein the corrected layout comprises a plurality of corrected figures, and the corrected figures extend along a first direction; acquiring an exposure layout according to the correction layout, wherein the exposure layout comprises a plurality of first exposure patterns corresponding to the correction patterns; And adopting a plurality of sampling steps to acquire a plurality of sampling points on the outline of the first exposure pattern so as to form a sampling pattern, wherein a segmentation section is arranged between every two adjacent sampling points, and the ith sampling step comprises the following steps: Acquiring an ith sampling point on the outline of the first exposure pattern; Acquiring an L-th position point on a correction pattern corresponding to the first exposure pattern, wherein the L-th position point corresponds to the i-th sampling point; Acquiring the curvature of an ith sampling point; acquiring a first offset between an ith sampling point and an L-th position point; acquiring a second offset of a profile line of the correction pattern between an L-1 position point and an L-1 position point, wherein the L-1 position point corresponds to an i-1 sampling point on the first exposure pattern; the step of acquiring the (i+1) th sampling step according to the curvature of the (i) th sampling point, the first offset and the second offset comprises the steps of acquiring a first weight, a second weight and a third weight, and acquiring the sampling step according to the curvature of the (i) th sampling point, the first offset and the second offset , wherein, For a first offset between the i-th sample point and the L-th position point, To correct the second offset of the profile line of the pattern between the L-1 th position point and the L-th position point, For the curvature of the i-th sampling point, For the minimum dimension of the graphic design rule, N is an adjustable variable, i is a natural number greater than 0, the value of L is the same as the value of i, As a first weight to be used, As a result of the second weight being set, As a result of the third weight being given, First weight Wherein Mmax is the maximum dimension of the correction pattern in the second direction, which is perpendicular to the first direction, mmin is the minimum dimension of the correction pattern in the second direction, a third weight w3=0.2w1, Second weight Wherein Curmax is the maximum curvature of the first exposure pattern profile in the exposure layout; and acquiring an i+1th sampling point on the outline of the first exposure pattern according to the i+1th sampling step length.
  2. 2. The optical proximity correction method of claim 1 wherein the method of obtaining the curvature of the i-th sampling point includes, when i=0, the sampling point being a starting sampling point having a curvature of 0, when i=1, the curvature of the first sampling point being a curvature of a segment between the first sampling point and the starting sampling point, and when i=2, the curvature of the second sampling point being a curvature of a segment between the second sampling point and the first sampling point.
  3. 3. The optical proximity correction method of claim 1 wherein the method of obtaining a second offset of the contour line of the correction pattern between the L-1 th position point and the L-th position point includes, when i=0, the second offset being 0, when i=1, the second offset being an offset of the contour line of the correction pattern between the start position point and the first position point, and when i=2, the second offset being an offset of the contour line of the correction pattern between the first position point and the second position point, the start position point corresponding to the start sampling point, the first position point corresponding to the first sampling point, and the second position point corresponding to the second sampling point.
  4. 4. The optical proximity correction method of claim 1 wherein the method of obtaining a first offset between the i-th sample point and the L-th location point comprises, when i=0, the first offset being an offset between the start sample point and the start location point, when i=1, the first offset being an offset between the first sample point and the first location point, and when i=2, the first offset being an offset between the second sample point and the second location point.
  5. 5. The optical proximity correction method of claim 1 further comprising edge placement error correction of the sampled pattern.
  6. 6. The optical proximity correction method according to claim 1, wherein the method for obtaining the adjustable variable N includes obtaining a plurality of sampling points on the profile of the first exposure pattern by sampling for a plurality of times to form a sampling pattern, dividing the profile of the first exposure pattern with the adjacent sampling points, judging the number of the dividing sections, increasing the value of N to be smaller than 1 if the number of the dividing sections is larger than a range of a preset value, decreasing the value of N to be larger than 1 if the number of the dividing sections is smaller than the preset value, and re-obtaining a plurality of sampling points on the profile of the first exposure pattern by sampling for a plurality of times according to the value of N until the number of the dividing sections satisfies the range of the preset value.
  7. 7. The method of claim 6, wherein if the number of segments of the segment satisfies a range of predetermined values, the value of N is 1.

Description

Optical proximity correction method Technical Field The invention relates to the field of semiconductor manufacturing, in particular to an optical proximity correction method. Background In order to transfer the pattern from the reticle to the surface of the silicon wafer, an exposure step, a development step performed after the exposure step, and an etching step after the development step are generally required. In the exposure step, light irradiates the silicon wafer coated with the photoresist through a light-transmitting area in the mask, the photoresist is subjected to chemical reaction under the irradiation of the light, in the development step, a photoetching pattern is formed by utilizing the difference of the dissolution degree of the photosensitive photoresist and the non-photosensitive photoresist to the developer, the mask pattern is transferred to the photoresist, and in the etching step, the silicon wafer is etched based on the photoetching pattern formed by the photoresist layer, and the pattern of the mask is further transferred to the silicon wafer. In semiconductor manufacturing, as the design size is continuously reduced, the design size is more and more close to the limit of a photoetching imaging system, the diffraction effect of light becomes more and more obvious, optical image degradation is finally generated on a design pattern, the actually formed photoetching pattern is severely distorted relative to the pattern on a mask plate, and finally the actual pattern formed by photoetching on a silicon wafer is different from the design pattern, and the phenomenon is called optical proximity effect (OPE: optical Proximity Effect). In order to correct the optical proximity effect, an optical proximity correction (OPC: optical Proximity Correction) is generated. The core idea of the optical proximity correction is to build an optical proximity correction model based on the consideration of canceling the optical proximity effect, and design a photomask pattern according to the optical proximity correction model, so that although the optical proximity effect occurs in the lithographic pattern corresponding to the photomask pattern, since the cancellation of the phenomenon has been considered when designing the photomask pattern according to the optical proximity correction model, the lithographic pattern after lithography is close to the target pattern that the user actually wants. However, the prediction accuracy of the existing optical proximity correction model is still to be improved. Disclosure of Invention The invention solves the technical problem of providing an optical proximity correction method to improve the prediction accuracy of the existing optical proximity correction model. In order to solve the technical problems, the technical scheme of the invention provides an optical proximity correction method, which comprises the steps of providing a correction layout, wherein the correction layout comprises a plurality of correction patterns, the correction patterns extend along a first direction, acquiring an exposure layout according to the correction layout, the exposure layout comprises a plurality of first exposure patterns corresponding to the correction patterns, acquiring a plurality of sampling points on the outline of the first exposure patterns by adopting a plurality of sampling steps so as to form sampling patterns, a segmentation section is arranged between every two adjacent sampling points, the ith sampling step comprises the steps of acquiring an ith sampling point on the outline of the first exposure patterns, acquiring an L-th position point on the correction patterns corresponding to the first exposure patterns, the L-th position point corresponds to the ith sampling point, acquiring curvature of the ith sampling point, acquiring a first offset between the ith sampling point and the L-1 th position point, acquiring a second offset of a contour line between the L-1 th position point and the ith sampling point, the L-1 th position point corresponds to the ith sampling point on the first exposure patterns, and acquiring a sampling step length of the ith sampling point according to the first curvature of the i-1 st offset and the i+1 th sampling point, and acquiring a sampling step length of the sampling point on the first offset of the sampling point according to the first curvature of the i+1. Optionally, the method for acquiring the (i+1) th sampling step length according to the curvature of the (i) th sampling point, the first offset and the second offset comprises the steps of acquiring a first weight, a second weight and a third weight, and acquiring the sampling step length according to the first weight, the second weight, the third weight, the curvature of the (i) th sampling point, the first offset and the second offset, wherein,For a first offset between the i-th sample point and the L-th position point,To correct the second offset of the profile line of the