OPC correction method and system, and layout
By segmenting and correcting the lines with corners in the photolithography process using OPC, the defect problem caused by the photomask being too close was solved, improving the photomask yield and the coverage of the metal layer and via layer, thus increasing the product yield.
Patent Information
- Application Number
- CN202511712957.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-03-06
AI Technical Summary
In photolithography, the optical proximity effect can cause the photomasks to be too close together, resulting in defects during the fabrication of the photomasks, making them unusable. Furthermore, the coverage of the metal layer and the via layer may not meet the standards, leading to a decrease in product yield.
By selecting line graphics with corners, segmenting them using different cutting points, and performing OPC correction on the segmented lines, the first line edge segment is expanded outward to the periphery of the corner, while the second and third line edge segments are shrunk inward to the interior of the line graphic, until the error is within a preset threshold range.
The increased distance between photomasks helps avoid defects in photomask manufacturing, improves the photomask pass rate, and enhances the coverage of the metal layer and via layer, thereby improving product yield.
Smart Images
Figure CN121613671A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor technology, and in particular to an OPC correction method, system, and layout. Background Technology
[0002] In photolithography, due to the optical proximity effect, there will be some discrepancies between the designed circuit layout and the actual pattern formed on the wafer. With the continuous advancement of technology nodes, Optical Proximity Correction (OPC) technology has emerged. Corner rounding is a common optical effect in OPC, especially in the back-end metal layer and via layer layouts of integrated circuit manufacturing processes.
[0003] In chips, metal layers serve as metal connections, enabling energy transfer between components through the conductivity of the metal layer circuitry. For metal layers with hole-shaped patterns, all edges are left unsegmented during OPC correction. For metal layers with line endpoint patterns, the line endpoints (located at the ends of the pattern) are unsegmented, while the long edges are segmented. There is a type of pattern that falls between hole-shaped and line endpoint patterns, possessing both long and short edges. Currently, the OPC correction method for this type leaves all edges unsegmented. However, the photomask on the short edge protrudes excessively outward. In layout-based designs, this results in photomasks being too close together during fabrication, which is constrained by actual manufacturing processes. Excessive proximity leads to defects in the photomask during fabrication, rendering the entire photomask unusable.
[0004] It should be noted that the information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention
[0005] The purpose of this invention is to provide an OPC correction method, system, and layout to solve the problem that when a graphic based on a layout design is manufactured, the distance between photomasks is too close, resulting in defects in the photomasks during manufacturing and rendering the entire photomask unusable.
[0006] To solve the above-mentioned technical problems, the present invention provides an OPC correction method, comprising:
[0007] A layout is provided, the layout comprising multiple metal layer patterns;
[0008] Line patterns with corners are selected from the plurality of metal layer patterns. The line patterns have a first line edge and a second line edge, and the length of the first line edge is less than the length of the second line edge.
[0009] Different cutting points are used to set cutting points for the first line edge and the second line edge, and cutting line segments are formed. The cutting line segments include the first line edge segment obtained after setting the cutting point along the line edge of the corner, the second line edge segment formed after setting the cutting point along the first line edge, and the third line edge segment formed after setting the cutting point along the second line edge.
[0010] The segmentation line is corrected using OPC, which expands the first line edge segment outward to the periphery of the corner, and shrinks the second and third line edge segments inward to the interior of the line graphic.
[0011] Preferably, the method further includes:
[0012] After performing OPC correction on the segmented line, the edge position error after this OPC correction is obtained. If the error is not less than a preset threshold range, the segmented line is corrected again by OPC until the edge position error is less than the preset threshold range.
[0013] Preferably, the length of the second line side is less than twice the length of the first line side.
[0014] Preferably, the corner is a convex corner, which is an angle located at the endpoints of two adjacent first line sides and second line sides with a preset angle less than or equal to 90°.
[0015] Preferably, the line graphic includes a rectangle, and the convex corner has a 90-degree angle.
[0016] Preferably, the step of setting different slicing points for the first line edge and the second line edge to form slicing segments includes:
[0017] Two dividing points are formed on the first line edge and the second line edge respectively, dividing the first line edge and the second line edge into three dividing line segments respectively.
[0018] Preferably, the lengths of the two sides of the first line segment are equal.
[0019] Based on the same inventive concept, the present invention also provides an OPC correction system, comprising:
[0020] A filtering module is used to provide a layout, the layout including multiple metal layer patterns; and to filter out line patterns with corners from the multiple metal layer patterns, the line patterns having a first line edge and a second line edge, the length of the first line edge being less than the length of the second line edge.
[0021] The segmentation module is used to set different segmentation points for the first line edge and the second line edge, and form segmentation line segments. The segmentation line segments include a first line edge segment obtained after setting the segmentation point along the line edge at the corner, a second line edge segment formed after setting the segmentation point along the first line edge, and a third line edge segment formed after setting the segmentation point along the second line edge.
[0022] The correction module is used to perform OPC correction on the segmented line, expanding the first line edge segment outward to the periphery of the corner, and shrinking the second and third line edge segments inward to the interior of the line graphic.
[0023] Preferably, it further includes:
[0024] The calculation module is used to perform OPC correction on the segmented line segment, obtain the edge position error after the current OPC correction, and if the error is not less than a preset threshold range, then perform OPC correction on the segmented line segment again until the edge position error is less than the preset threshold range.
[0025] Based on the same inventive concept, the present invention also provides a layout comprising:
[0026] The method described above is used to correct the selected line graphics with corners in the layout.
[0027] Compared with the prior art, the OPC correction method of the present invention has the following advantages:
[0028] This invention corrects the segmented lines using OPC (Optical Process Control) techniques, expanding the first line edge segment outwards to the outer perimeter of the corners and shrinking the second and third line edge segments inwards into the interior of the line graphic. When fabricating a photomask using the OPC-corrected graphic, the distance between adjacent photomasks can be increased, thereby avoiding limitations imposed by manufacturing processes, preventing photomask defects, and improving the photomask production yield.
[0029] Furthermore, by applying OPC correction to the segmented lines, the first edge segment is expanded outwards to the periphery of the corners, while the second and third edge segments are shrunk inwards to the interior of the line pattern. This results in a more square outline at the corners. When the OPC-corrected pattern is transferred to the wafer, the resulting etched pattern more closely resembles the shape and size of the metal layer pattern design, reducing distortion at the corners. This improves the coverage of subsequent metal layers and via layers formed based on this layout, leading to better contact between the metal layers and the contact holes or vias on the upper and lower layers, thus improving product yield.
[0030] The OPC correction system and layout provided by this invention belong to the same inventive concept as the OPC correction method provided by this invention. Therefore, the OPC correction system and layout provided by this invention possess at least all the advantages of the OPC correction method provided by this invention. When fabricating photomasks using the layout after OPC correction, the distance between two adjacent photomasks can be increased, thereby avoiding the constraints of manufacturing process conditions on photomask fabrication, preventing photomask defects, and improving the photomask fabrication yield. Simultaneously, it also improves the coverage of the metal layer and via layer subsequently formed based on this layout, thereby enabling better contact between the metal layer and the contact holes or vias on the upper and lower layers, improving product yield. Attached Figure Description
[0031] Figure 1 This is a schematic diagram showing the positional relationship between the metal layer pattern and the via layer pattern in one embodiment;
[0032] Figure 2 This is a schematic diagram showing the positional relationship between adjacent photomasks during the fabrication of a photomask in one embodiment;
[0033] Figure 3 This is a schematic diagram of the metal layer pattern in one embodiment of the present invention;
[0034] Figure 4 This is a schematic diagram illustrating the OPC correction of a metal layer pattern using the method disclosed in this embodiment of the present invention.
[0035] Figure 5 This is a schematic diagram of the photomask obtained after OPC correction in one embodiment of the present invention;
[0036] Figure 6 This is a schematic diagram of the contour obtained by simulation of the metal layer pattern on the photomask in one embodiment of the present invention;
[0037] Figure 7 This is a schematic diagram showing the positional relationship of a metal layer photomask fabricated after OPC correction in one embodiment of the present invention during fabrication.
[0038] In the picture,
[0039] 100 - Metal layer pattern; 110 - First line edge;
[0040] 120 - Second line edge; 130 - Corner;
[0041] 140 - First dividing point; 150 - Second dividing point;
[0042] 160 - Second line edge segment; 170 - First line edge segment;
[0043] 180 - Third line edge segment; 200 - First contour;
[0044] 300 - Through - hole layer pattern; 400 - First metal layer mask;
[0045] 500 - Second metal layer mask; 600 - Second contour. Detailed implementation manners
[0046] To make the objectives, advantages, and features of the present invention clearer, the OPC correction method, system, and layout proposed by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the accompanying drawings are all in very simplified forms and use non - precise scales, and are only used to conveniently and clearly assist in explaining the objectives of the embodiments of the present invention. It should be understood that the drawings in the specification do not necessarily show the specific structure of the present invention in proportion, and the illustrative features used to explain certain principles of the present invention in the drawings of the specification will also adopt a slightly simplified drawing method. The specific design features of the present invention disclosed herein, such as specific dimensions, directions, positions, and shapes, will be partially determined by the specific application and usage environment. Also, in the following described embodiments, sometimes the same reference numerals are used between different drawings to represent the same part or parts with the same functions, and the repeated description thereof is omitted. In this specification, similar reference numerals and letters are used to represent similar items. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.
[0047] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.
[0048] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above - mentioned terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.
[0049] Refer Figure 1 And Figure 2As shown, after OPC correction of the metal layer pattern 100, due to the outward protrusion of the short side, when the metal layer pattern 100 is transferred to the photomask to form the first metal layer photomask 400, the first metal layer photomask 400 located on the short side will also protrude outward. Therefore, during photomask fabrication, there will be a distance between adjacent first metal layer photomasks 400 (i.e., Figure 2 In the case of d1) being too close. Because the distance between two adjacent first metal layer photomasks 400 is too close, the manufacturing process of the first metal layer photomask 400 will be constrained by the manufacturing process conditions, resulting in defects in the first metal layer photomask 400 and causing the entire photomask to be scrapped.
[0050] In addition, continue to participate Figure 1 and Figure 2 As shown, for the via layer pattern 300 formed at the corner 130 of the metal layer pattern 100, simulation was used to obtain the following... Figure 1 The first contour 200 is described above. From the positional relationship between the first contour 200 and the via layer pattern 300, it can be seen that the first contour 200 does not completely cover the via layer pattern 300. Due to the corner rounding effect, this results in substandard coverage of the metal layer and via layer subsequently formed based on this layout, or a reduction in the area of the upper and lower stacked layers, leading to a decrease in product yield.
[0051] The core idea of this invention is to provide an OPC correction method that can improve the coverage of the metal layer and the via layer, and increase the distance between two adjacent metal layer photomasks during fabrication, thereby improving the pass rate of metal layer photomask fabrication.
[0052] To achieve the above-mentioned goals, this invention provides an OPC correction method, which includes... Figures 1 to 7 A specific implementation of the disclosed OPC correction method is described. The OPC correction method includes the following steps S1 to S4.
[0053] Step S1: Provide a layout, the layout comprising multiple metal layer patterns 100.
[0054] Specifically, refer to Figure 3 As shown, a layout is provided, which includes multiple metal layer patterns 100. The shapes of the metal layer patterns 100 in the layout include circular structures, rectangular structures, square structures, L-shaped structures, etc.
[0055] Step S2: Select line patterns with corners 130 from the plurality of metal layer patterns 100. The line patterns have a first line edge 110 and a second line edge 120, and the length of the first line edge 110 is less than the length of the second line edge 120.
[0056] Specifically, refer to Figure 3 and Figure 4As shown, line graphics with corners 130 are selected from multiple metal layer graphics 100. These line graphics include not only corners 130, but also first line edges 110 and second line edges 120. The length of the first line edge 110 is less than the length of the second line edge 120. In the specific selection process, the specific data of the metal layer graphics 100 can be obtained from the GDS file generated during the layout design. For example, the side lengths of the line edges of the metal layer graphics 100. During the selection process, based on the data in the GDS file, metal layer graphics 100 with a second line edge 120 length less than twice the length of the first line edge are selected as line graphics. The selected line edge graphics include two first line edges 110 and two second line edges 120.
[0057] The corner 130 is a convex corner, which is an angle located at the endpoints of two adjacent first line sides 110 and second line sides 120 with a preset angle less than or equal to 90°.
[0058] During the screening process, a rectangular metal layer pattern 100 is selected as the line pattern. For the rectangular line pattern, the convex corner angle is 90 degrees.
[0059] Step S3: Use different cutting points to set cutting points for the first line edge 110 and the second line edge 120, and form cutting line segments. The cutting line segments include the first line edge segment 170 obtained after setting the cutting point along the line edge of the corner 130, the second line edge segment 160 formed after setting the cutting point along the first line 110, and the third line edge segment 180 formed after setting the cutting point along the second line edge 120.
[0060] Specifically, refer to Figures 3 to 5 As shown, different dividing points are used to set the dividing points for the first line edge 110 and the second line edge 120, forming dividing line segments, including:
[0061] Two dividing points are formed at the first line edge 110 and the second line edge 120, respectively, dividing the first line edge 110 and the second line edge 120 into three dividing line segments. A first dividing point 140 and a second dividing point 150 are formed at the first line edge 110 and the second line edge 120, respectively, to form a first line edge segment 170 surrounding the corner 130 (i.e., Figure 5 The first line edge 110 consists of a red line segment 170, a second line edge segment 160, and a third line edge segment 180. The second line edge segment 160 is located in the middle of the first line edge 110. The third line edge segment 180 is located in the middle of the second line edge 120. Preferably, the lengths of both sides of the first line edge segment 170 are equal, so that when forming the metal layer pattern 100, the outline formed at the corner 130 is more square, thus improving the process window.
[0062] Step S4: Perform OPC correction on the segmented line segments, expand the first line edge segment 170 to the periphery of the corner 130, and shrink the second line edge segment 160 and the third line edge segment 180 to the inside of the line pattern.
[0063] Specifically, refer Figures 1 to 7 As shown, perform OPC correction on the segmented line segments, expand the first line edge segment 170 to the periphery of the corner 130, and shrink the second line edge segment 160 and the third line edge segment 180 to the inside of the line pattern. For the range where the first line edge segment 170 is expanded to the periphery of the corner 130 and the range where the second line edge segment 160 and the third line edge segment 180 are shrunk to the inside of the line pattern, dynamic adjustment is performed based on the structure of the simulation.
[0064] This method further includes: after performing OPC correction on the segmented line segments, obtaining the edge position error after this OPC correction. If the error is not less than the preset threshold range, perform OPC correction on the segmented line segments again until the edge position error is less than the preset threshold range.
[0065] Using the method disclosed in this embodiment to simulate the selected metal layer pattern 100, the second contour 600 as Figure 6 described is obtained. It can be seen from the second contour 600 that the second contour 600 formed by the corner 130 changes from a square corner to a rounded corner. When the first line edge segment 170 is expanded to the periphery of the corner 130, the shape at the corner 130 of the second contour 600 will be more square, closer to the designed shape and size of the metal layer pattern 100, and reducing the distortion at the corner 130. The second contour 600 can completely cover the via layer pattern 300, improving the coverage rate of the metal layer and the via layer formed based on this layout, so that the metal layer can better contact the upper and lower layer contact holes or vias, and improving the product yield.
[0066] Refer Figure 7 As shown, based on the OPC correction pattern formed by using the method disclosed in this embodiment, when manufacturing the second metal layer mask 500, the distance between two adjacent second metal layer masks 500 (i.e., Figure 7 d2 in) increases. Performing simulation on the metal layer pattern 100 after OPC correction, the area of the second contour 600 is increased by 12.5% compared to the first contour 200. The formed mask-mask distance is increased by 64.6%, thus avoiding the second metal layer mask 500 being restricted by the manufacturing process conditions, avoiding defects in the first metal layer mask 400, and improving the qualification rate of mask manufacturing.
[0067] To implement the above idea, this embodiment also discloses an OPC correction system, including:
[0068] A filtering module is used to provide a layout, the layout including multiple metal layer graphics 100; and to filter out line graphics with corners 130 from the multiple metal layer graphics 100, the line graphics having a first line edge 110 and a second line edge 120, the length of the first line edge 110 being less than the length of the second line edge 120.
[0069] The segmentation module is used to set different segmentation points for the first line edge 110 and the second line edge 120, and form segmented line segments. The segmented line segments include a first line edge segment 170 obtained after setting the segmentation point along the line edge of the corner 130, a second line edge segment 160 formed after setting the segmentation point along the first line edge 110, and a third line edge segment 180 formed after setting the segmentation point along the second line edge 120.
[0070] The correction module is used to perform OPC correction on the segmented line, expanding the first line edge segment 170 outward to the periphery of the corner 130, and shrinking the second line edge segment 160 and the third line edge segment 180 inward to the interior of the line graphic.
[0071] It also includes a calculation module, which is used to obtain the edge position error after performing OPC correction on the segmented line segment. If the error is not less than a preset threshold range, the segmented line segment is corrected again until the edge position error is less than the preset threshold range.
[0072] To achieve the above idea, this embodiment also discloses a layout, including:
[0073] The line graphics with 130° corners selected in the layout are corrected using the method described above.
[0074] The OPC correction system and layout provided in this embodiment belong to the same inventive concept as the OPC correction method provided in this embodiment. Therefore, the OPC correction system and layout provided in this embodiment have at least all the advantages of the OPC correction method provided in this embodiment. When fabricating a photomask using the OPC-corrected layout, the distance between two adjacent photomasks can be increased, thereby avoiding the constraints of manufacturing process conditions on photomask fabrication, preventing photomask defects, and improving the photomask fabrication yield. At the same time, it also improves the coverage of the metal layer and via layer subsequently formed based on this layout, thereby enabling better contact between the metal layer and the contact holes or vias of the upper and lower layers, improving product yield.
[0075] In summary, the above embodiments have provided detailed descriptions of different configurations of the OPC correction method and system, and layout. Of course, the above descriptions are only descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention in any way. The present invention includes but is not limited to the configurations listed in the above embodiments. Those skilled in the art can draw inferences from the above embodiments. Any changes or modifications made by those skilled in the art based on the above disclosure are within the scope of protection of the claims.
Claims
1. An OPC correction method characterized by, The method comprises the following steps: providing a layout, wherein the layout comprises a plurality of metal layer patterns; selecting a line pattern with a corner from the plurality of metal layer patterns, wherein the line pattern has a first line side and a second line side, and the length of the first line side is less than the length of the second line side; setting different split points on the first line side and the second line side to form split line segments, wherein the split line segments comprise a first line side segment obtained by setting split points on the line side along the corner, a second line side segment obtained by setting split points on the first line side, and a third line side segment obtained by setting split points on the second line side; performing OPC correction on the split line segments, wherein the first line side segment is expanded outward to the periphery of the corner, and the second line side segment and the third line side segment are shrunk inward to the inside of the line pattern.
2. The OPC correction method according to claim 1, wherein The method further comprises the following steps: after the OPC correction on the split line segments, obtaining an edge position error after the current OPC correction, and if the error is not less than a preset threshold range, performing OPC correction on the split line segments again until the edge position error is less than the preset threshold range.
3. The OPC correction method according to claim 1, wherein The length of the second line side is less than twice the length of the first line side.
4. The OPC correction method of claim 1, wherein The corner is a convex corner, and the convex corner is an angle between two adjacent first line sides and second line sides, and the angle is less than a preset angle, wherein the preset angle is less than or equal to 90°.
5. The OPC correction method according to claim 4, wherein The line pattern comprises a rectangle, and the convex corner is 90°.
6. The OPC correction method according to claim 5, wherein The step of setting different split points on the first line side and the second line side to form split line segments comprises the following steps: forming two split points on the first line side and the second line side respectively, and dividing the first line side and the second line side into three split line segments.
7. The OPC correction method according to claim 6, wherein The lengths of the two sides of the first line side segment are equal.
8. An OPC correction system characterized by comprising: The method comprises the following steps: providing a layout, wherein the layout comprises a plurality of metal layer patterns; selecting a line pattern with a corner from the plurality of metal layer patterns, wherein the line pattern has a first line side and a second line side, and the length of the first line side is less than the length of the second line side; setting different split points on the first line side and the second line side to form split line segments, wherein the split line segments comprise a first line side segment obtained by setting split points on the line side along the corner, a second line side segment obtained by setting split points on the first line side, and a third line side segment obtained by setting split points on the second line side; performing OPC correction on the split line segments, wherein the first line side segment is expanded outward to the periphery of the corner, and the second line side segment and the third line side segment are shrunk inward to the inside of the line pattern.
9. The OPC correction system of claim 8, wherein The method further comprises the following steps: after the OPC correction on the split line segments, obtaining an edge position error after the current OPC correction, and if the error is not less than a preset threshold range, performing OPC correction on the split line segments again until the edge position error is less than the preset threshold range.
10. A layout characterized by, The method comprises the following steps: The method as claimed in any one of claims 1 to 7 is used to correct the selected line pattern with corners in the layout.