Processing method of metal layer layout
By preprocessing the convex corner pattern of the metal layer layout and correcting the optical proximity effect, the problem of process hotspots in the convex corner pattern during exposure imaging was solved, and stable exposure effect was achieved under small process window.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HANGZHOU HFC SEMICONDUCTOR CO
- Filing Date
- 2026-03-24
- Publication Date
- 2026-05-12
AI Technical Summary
In metal layer layouts, convex corner patterns are limited by optical imaging resolution due to their small feature size, leading to process hotspot problems during exposure imaging, such as short circuits, open circuits, and poor connections.
By preprocessing the convex corner pattern in the metal layer layout before OPC processing, including edge shrinking and edge expansion, adjusting the distance between the convex corner edge and the background pattern, and combining optical proximity effect correction technology, the shape of the convex corner pattern is optimized to reduce rounded corner distortion and ensure the connection stability between the convex corner and the corner.
This method effectively eliminates process hotspots in convex corner patterns within a small process window, reduces the risk of short circuits between convex corner patterns and surrounding metal layers, and maintains the clarity of feature patterns and the quality of conductive contacts.
Smart Images
Figure CN122018248A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a method for processing metal layer patterns. Background Technology
[0002] With advancements in semiconductor lithography technology, integrated circuit design dimensions are gradually shrinking. The increasing complexity of metal layer structures leads to reduced layout process margins, exacerbating the conflict between optical proximity effects and process windows. Although Optical Proximity Correction (OPC) can resolve most layout deviations caused by optical proximity effects, complex layouts may still exhibit process hotspots after OPC processing.
[0003] In particular, in metal layer patterns, convex corner patterns connected to corners on the short side suffer from severe circularity distortion during exposure imaging due to their small feature size and limited optical imaging resolution. For example... Figure 1 As shown, under the constraint of a small process window, even after OPC correction, this type of convex corner pattern will still experience process hotspots such as short circuits, open circuits, and poor connections between its own exposed pattern and the surrounding exposed metal layer.
[0004] Therefore, a method for processing metal layer layouts needs to be designed to improve the above problems. Summary of the Invention
[0005] This invention provides a method for processing metal layer patterns to improve the technical problem of process hotspots generated during exposure imaging when convex corner patterns with corners in existing patterns are limited by a small process window.
[0006] In a first aspect, the present invention provides a method for processing a metal layer layout, the method comprising: S1. Obtain the metal layer layout and the via layer layout corresponding to the metal layer layout; S2. Extract the first process hotspot pattern and the background pattern within a preset range around the first process hotspot pattern from the metal layer layout according to the first preset rule; wherein, the metal layer layout includes a metal pattern formed by the orthogonal intersection of two metal strips, and a through-hole pattern is correspondingly provided on the intersection area of the two metal strips, the first process hotspot pattern includes the intersection area and a convex corner pattern extending from the metal pattern relative to the intersection area, and the first distance between the convex corner pattern and the background pattern is less than the first preset distance; S3. Shrink the convex corner edge on the convex corner pattern with a first preset displacement to obtain a pre-processed layout. S4. Perform optical proximity effect correction processing on the preprocessed layout to obtain the corrected layout of the metal layer layout; S5. Perform simulation processing on the modified layout according to the second preset rule to obtain a simulation image.
[0007] In one example of the present invention, the metal pattern forms a corner pattern at the intersection area, and the first process hot spot pattern has a first adjacent side and a second adjacent side connected at both ends of the convex corner edge. The first adjacent side is connected to the corner pattern, and the second adjacent side is away from the corner pattern.
[0008] In one example of the present invention, step S3 further includes: obtaining a second distance between the second adjacent edge and the background pattern; when the second distance is greater than the second preset distance, expanding the second adjacent edge by a second preset displacement, so that the second distance is greater than or equal to the second preset distance.
[0009] In one example of the present invention, step S5 further includes: extracting a second hotspot process pattern from the simulation image corresponding to the first hotspot process pattern; if the second hotspot process pattern meets the preset process requirements, then outputting the simulation image.
[0010] In one example of the present invention, the step of outputting the simulation image if the second hot spot process pattern meets the preset process requirements includes: if the second hot spot process pattern does not have a bridging image or a broken line image and the coverage rate of the metal pattern over the through hole pattern in the second hot spot process pattern is greater than or equal to the preset coverage rate, then the simulation image is output.
[0011] In one example of the present invention, step S5 further includes: if the second hot spot process pattern does not meet the preset process requirements, repeat steps S3 to S5 until the second hot spot process pattern meets the preset process requirements.
[0012] In one example of the present invention, the first preset displacement is the difference between the first preset distance and the first distance.
[0013] In one example of the present invention, the portion of the background pattern near the convex corner pattern is a metal strip that is parallel or perpendicular to the outer edge of the convex corner pattern.
[0014] In one example of the present invention, the portion of the background pattern near the convex corner pattern is the vertical angle of the L-shaped metal strip.
[0015] In one example of the present invention, the first distance is the shortest distance between the convex side and the vertical corner vertex.
[0016] This invention provides a method for processing metal layer patterns. Before OPC processing, it pre-adjusts convex corner patterns that cause process hotspots in the metal layer pattern. By shrinking the edges of the convex corners, it mitigates the rounding distortion of convex corners and corners during exposure, maintains the clarity of the feature pattern, and reduces the risk of short circuits between the convex corner pattern and surrounding metal layer patterns after exposure. This correction method can eliminate process hotspots caused by such convex corner patterns during exposure even in small process windows, overcoming the limitation of OPC technology in fully correcting small feature-size patterns. Attached Figure Description
[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other embodiments based on these drawings without inventive effort.
[0018] In the attached diagram: Figure 1 This is a schematic diagram of the process hotspots generated after exposure of a convex corner pattern in a metal layer layout that has only undergone OPC processing. Figure 2 This is a flowchart illustrating an optical proximity effect correction method in one embodiment of the present invention. Figure 3 This is a schematic diagram of an edge-to-edge hotspot structure in a metal layer layout according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the preprocessing method for an edge-to-edge hotspot structure in one embodiment of the present invention; Figure 5 This is a schematic diagram of a corner-to-corner hotspot structure in a metal layer layout according to an embodiment of the present invention; Figure 6 A comparison of the layout and exposure images of a hot spot area in a metal layer layout before and after correction by the correction method of this invention; Figure 7 This is a schematic diagram showing the number of short-circuit repairs after a metal layer layout has been corrected using the correction method of this invention.
[0019] The attached figures are labeled as follows: 100. Metal pattern; 110. First process hot spot pattern; 111. Convex corner edge; 112. First adjacent edge; 113. Second adjacent edge; 130. Corner pattern; 131. First corner edge; 132. Second corner edge; 133. Third corner edge; 200. Background pattern; 210. First opposite edge; 220. Second opposite edge; 230. Diagonal pattern; 231. First diagonal edge; 232. Second diagonal edge; 300. Through hole pattern. Detailed Implementation
[0020] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.
[0021] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as part of the scope of the invention.
[0022] In the first aspect, such as Figure 2 As shown, the present invention provides a method for processing metal layer layouts, the correction method comprising the following steps: Step S1: Obtain the metal layer layout and the via layer layout corresponding to the metal layer layout.
[0023] like Figure 3 and Figure 5 As shown, in step S1, a metal layer layout and a corresponding via layer layout are provided and input. The via layer image to be exposed in the via layer layout can be located on the upper or lower layer of the metal layer image to be exposed in the metal layer layout.
[0024] Next, step S2 is executed to extract the first process hotspot pattern 110 and the background pattern 200 within a preset range around the first process hotspot pattern 110 in the metal layer layout according to the first preset rule.
[0025] like Figure 3 and Figure 5As shown, in step S2, several first process hotspot patterns 110 to be corrected and eliminated and background patterns 200 around the first process hotspot patterns 110 are extracted from the metal layer layout according to the first preset rule. The background patterns 200 are located within a preset range around the first process hotspot patterns 110. For example, specifically, the metal layer layout includes a metal pattern 100 formed by two orthogonally intersecting metal strips, and a through-hole pattern 300 is correspondingly provided on the intersection area of the two metal strips. The first process hot spot pattern 110 includes an intersection area and a convex corner pattern extending from the metal pattern 100 relative to the intersection area. The first process hot spot pattern 110 includes a convex corner edge 111, a first adjacent edge 112, and a second adjacent edge 113. One end of the convex corner edge 111 is connected to the first adjacent edge 112, and the other end of the convex corner edge 111 is connected to the second adjacent edge 113. The convex corner edge 111 and the first adjacent edge 112 have a 90° angle inside the convex corner pattern, and the convex corner edge 111 and the second adjacent edge 113 have a 90° angle inside the convex corner pattern. A background pattern 200 is arranged around the convex corner pattern. The background pattern 200 is located at least outside the convex corner edge 111, and the shortest distance between the background pattern 200 and the convex corner edge 111 is less than a first preset distance, so that the convex corner pattern is prone to bridging and short-circuiting with the background pattern 200 after exposure. It should be noted that both the convex corner pattern and the background pattern 200 in the metal layer pattern are metal layer patterns to be exposed and formed on the wafer.
[0026] like Figure 3 and Figure 5 As shown, in some embodiments, two intersecting metal strips in the metal pattern 100 also form a corner pattern 130 at the intersection area, which is located on one side of the first process hotspot pattern 110. Specifically, the first process hotspot pattern 110 is connected to the corner pattern 130 on one side of the first adjacent side 112, and the second adjacent side 113 of the first process hotspot pattern 110 is away from the corner pattern 130. The corner pattern 130 includes a first corner edge 131, a second corner edge 132, and a third corner edge 133 connected in sequence, with the first corner edge 131, the second corner edge 132, and the third corner edge 133 connected end to end to form the corner pattern 130. One end of the first adjacent side 112 is connected to one end of the first corner edge 131, and the first adjacent side 112 and the first corner edge 131 have a 270° angle between them inside the pattern. The second corner edge 132 is connected to the endpoint of the first corner edge 131 furthest from the first adjacent edge 112, and the second corner edge 132 is arranged opposite to the first adjacent edge 112. The third corner edge 133 is connected to the second corner edge 132, and the third corner edge 133 is parallel to the first corner edge 131.
[0027] Next, step S3 is executed to shrink the convex corner edge 111 on the convex corner pattern with the first preset displacement to obtain the pre-processed layout.
[0028] In step S3, when the first distance between the convex corner edge 111 and the background pattern 200 is less than the first preset distance (the first distance is the shortest distance between the convex corner edge 111 and the background pattern 200), the convex corner edge 111 on the first process hot spot pattern 110 is shrunken, and the second adjacent edge 113 on the first process hot spot pattern 110 is expanded, thereby shifting the first process hot spot pattern 110 to the side away from the corner pattern 130. This is to supplement the area of the first process hot spot pattern 110 on the side of the second adjacent edge 113 while adjusting the distance between the convex corner edge 111 and the background pattern 200, thereby effectively reducing the rounded corner distortion of the adjacent corner area in the convex corner pattern, preventing the convex corner pattern from bridging and short-circuiting with the surrounding background pattern 200 under small process window exposure, and ensuring that the first process hot spot area after exposure and the corresponding through hole pattern 300 have sufficient contact area to maintain good conductive contact.
[0029] like Figures 3 to 4 As shown, in some embodiments, step S3 includes: in the first process hot spot pattern 110, performing edge reduction processing on the convex corner edge 111 by a first preset displacement; and based on the first process hot spot pattern 110 after the convex corner edge 111 is reduced, performing edge expansion processing on the second adjacent edge 113 to obtain a pre-processed layout.
[0030] In some embodiments, the first preset displacement is the difference between a first preset distance and a first distance.
[0031] In some embodiments, such as Figure 3 and Figure 4 As shown, the step of expanding the second adjacent edge 113 includes: when the background pattern 200 includes a second opposing edge 220 directly opposite the second adjacent edge 113, and the second distance between the second opposing edge 220 and the second adjacent edge 113 is greater than a second preset distance, expanding the second adjacent edge 113 by a second preset displacement, and ensuring that the second distance is greater than or equal to the second preset distance. Wherein, the second distance is the shortest distance between the second adjacent edge 113 and the second opposing edge 220.
[0032] like Figures 3 to 4 As shown, in some embodiments, the portion of the background pattern 200 near the convex corner pattern is a metal strip parallel or perpendicular to the outer edge of the convex corner pattern. That is, the background pattern 200 and the first process hotspot pattern 110 have an edge-to-edge structure. The background pattern 200 includes a first opposing edge 210 directly opposite the convex corner edge 111. When the first distance between the first opposing edge 210 and the convex corner edge 111 is less than a first preset distance, the convex corner edge 111 is shrunk by a first preset displacement. Based on the first process hotspot pattern 110 after the convex corner edge 111 is shrunk, the second adjacent edge 113 is expanded to obtain a pre-processed layout.
[0033] like Figure 5 As shown, in some embodiments, the portion of the background pattern 200 near the convex corner pattern is the vertical angle of an L-shaped metal strip. The background pattern 200 includes a diagonal pattern 230 opposite to the convex corner pattern. The diagonal pattern 230 includes a first diagonal side 231 and a second diagonal side 232. The first diagonal side 231 and the second diagonal side 232 intersect to form the apex angle of the diagonal pattern 230. The first diagonal side 231 is parallel to the convex corner side 111, and the second diagonal side 232 is perpendicular to the first diagonal side 231. The first distance between the diagonal pattern 230 and the convex corner side 111 is the shortest distance between the convex corner side 111 and the vertex of the vertical angle, that is, the shortest distance between the intersection point of the convex corner side 111 and the first diagonal side 231 and the second diagonal side 232.
[0034] like Figures 3 to 5 As shown, in some embodiments, there is a width W between the first corner edge 131 and the third corner edge 133, where W is the shortest distance between the first corner edge 131 and the third corner edge 133. In the convex corner pattern, the length of the first adjacent edge 112 is greater than or equal to 0.1W and less than or equal to 1.5W. In this embodiment, because the feature distance of the first adjacent edge 112 connected to the corner is small, the connection position between the convex corner pattern and the corner pattern 130 is severely rounded during exposure, making it difficult to maintain the feature pattern after exposure and prone to short-circuiting with the background pattern 200 in the outer corner area. Through the preprocessing correction of this application, the convex corner pattern can be shifted to the side away from the corner, thereby mitigating the rounded distortion of the connection area between the convex corner and the corner during exposure and reducing the risk of short-circuiting between the convex corner pattern and the surrounding metal layer pattern after exposure.
[0035] Next, step S4 is performed to correct the optical proximity effect of the preprocessed layout to obtain the corrected layout of the metal layer layout.
[0036] In step S4, the optical proximity correction (OPC) software is used to correct the optical proximity effect of the preprocessed layout, resulting in a corrected layout. The optical proximity correction in this step can be either rule-based optical proximity correction (RBOPC) or model-based optical proximity correction (MBOPC). The correction rule can be any suitable rule, such as moving the edges of the first hot spot process pattern, corner pattern 130, and background pattern 200, or adding additional polygons to the corresponding positions of the convex corner pattern, corner pattern 130, and background pattern 200, etc., which will not be detailed here.
[0037] Next, step S5 is executed to perform simulation processing on the modified layout according to the second preset rule to obtain a simulation image.
[0038] In step S5, corresponding to the first hot spot process pattern, the second hot spot process pattern is extracted from the simulation image. If the second hot spot process pattern meets the preset process requirements, the simulation image is output.
[0039] In some embodiments, in step S5, for the second hotspot process pattern, if the second hotspot process pattern does not have a broken line image or a bridging image with the surrounding metal layer, and the coverage rate of the second hotspot process pattern for the via layer is greater than or equal to a preset coverage rate, then the corrected layout is output. Here, the coverage rate of the second hotspot process pattern for the via layer refers to the ratio of the overlapping area between the second hotspot process pattern and the via layer to the area of the via layer. The preset coverage rate can be set according to process requirements; for example, the preset coverage rate can be set to any value within the range of 90% to 98%, such as 90%, 92%, 95%, 97%, or 98%.
[0040] In addition, in some embodiments, if the second hot spot process pattern extracted in step S5 does not meet the preset process requirements, the second hot spot process pattern has a broken line image or a bridging image with the surrounding metal layer, or the coverage of the second hot spot process pattern for the via layer is less than the preset coverage, then steps S3 to S5 are repeated until the second hot spot process pattern meets the preset process requirements.
[0041] In some embodiments, when steps S3 to S5 are repeatedly executed, each time step S3 is executed, the first preset distance used to adjust the first distance between the convex corner edge 111 and the background pattern 200 is increased by a preset percentage. The preset percentage increase in the first preset distance can be 5% to 20%, for example, the preset percentage by which the first preset distance increases by its own length value each time step S3 is repeated can be 5%, 10%, 15%, or 20%. Optionally, the preset percentage increase in the first preset distance can be 10%.
[0042] In summary, this metal layer layout processing method, by transferring the convex corner pattern to the first adjacent side before OPC correction, adjusts the spacing between the convex corner pattern and the background pattern while supplementing the graphic area on the first adjacent side. This avoids bridging and short-circuiting between the convex corner pattern and the surrounding background pattern after exposure, and effectively ensures sufficient contact area between the convex corner pattern and the corresponding via pattern, preventing poor contact caused by insufficient coverage between the metal layer and the via layer after exposure. Figure 7 As shown, a metal layer layout generates 331,350 hot spots (such as short circuits) after direct exposure. However, by using the method of this application to process the metal layer layout, the number of hot spots generated after exposure can be reduced to 2,450.
[0043] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Anyone skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention. Anyone skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention.
Claims
1. A method for processing a metal layer layout, characterized in that, include; S1. Obtain the metal layer layout and the via layer layout corresponding to the metal layer layout; S2. Extract the first process hotspot pattern and the background pattern within a preset range around the first process hotspot pattern from the metal layer layout according to the first preset rule; wherein, the metal layer layout includes a metal pattern formed by the orthogonal intersection of two metal strips, and a through-hole pattern is correspondingly provided on the intersection area of the two metal strips, the first process hotspot pattern includes the intersection area and a convex corner pattern extending from the metal pattern relative to the intersection area, and the first distance between the convex corner pattern and the background pattern is less than the first preset distance; S3. Shrink the convex corner edge on the convex corner pattern with a first preset displacement to obtain a pre-processed layout. S4. Perform optical proximity effect correction processing on the preprocessed layout to obtain the corrected layout of the metal layer layout; S5. Perform simulation processing on the modified layout according to the second preset rule to obtain a simulation image.
2. The processing method according to claim 1, characterized in that, The metal pattern forms a corner pattern at the intersection area. The first process hot spot pattern has a first adjacent side and a second adjacent side connected at both ends of the convex corner edge. The first adjacent side is connected to the corner pattern, and the second adjacent side is away from the corner pattern.
3. The processing method according to claim 2, characterized in that, Step S3 further includes: Obtain the second distance between the second adjacent edge and the background pattern. When the second distance is greater than the second preset distance, expand the second adjacent edge by the second preset displacement, so that the second distance is greater than or equal to the second preset distance.
4. The processing method according to claim 3, characterized in that, Step S5 further includes: Corresponding to the first hotspot process pattern, the second hotspot process pattern is extracted from the simulation image. If the second hotspot process pattern meets the preset process requirements, the simulation image is output.
5. The processing method according to claim 4, characterized in that, If the second hotspot process pattern meets the preset process requirements, the simulation image is output, including: If the second hotspot process pattern does not have a bridging image or a broken line image, and the coverage rate of the metal pattern over the through-hole pattern in the second hotspot process pattern is greater than or equal to the preset coverage rate, then the simulation image is output.
6. The processing method according to claim 5, characterized in that, Step S5 further includes: If the second hot spot process pattern does not meet the preset process requirements, repeat steps S3 to S5 until the second hot spot process pattern meets the preset process requirements.
7. The processing method according to claim 1, characterized in that, The first preset displacement is the difference between the first preset distance and the first distance.
8. The processing method according to claim 1, characterized in that, The portion of the background pattern near the convex corner pattern consists of metal strips that are parallel or perpendicular to the outer edge of the convex corner pattern.
9. The processing method according to claim 1, characterized in that, The portion of the background pattern closest to the convex corner pattern is the vertical angle of the L-shaped metal strip.
10. The processing method according to claim 9, characterized in that, The first distance is the shortest distance between the convex side and the vertex of the vertical corner.