Sram mark pattern detection method
By employing sliding window technology in SRAM pattern inspection, the problems of slow delivery speed and low yield caused by insufficient resources have been solved, achieving efficient SRAM pattern inspection and reducing mask production risks.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI HUALI INTEGRATED CIRCUIT CORP
- Filing Date
- 2023-06-29
- Publication Date
- 2026-07-14
Smart Images
Figure CN116823773B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor technology, and in particular to a method for detecting SRAM marker patterns. Background Technology
[0002] With the development of semiconductor technology, the requirements for chip performance and power consumption are becoming increasingly stringent, and the critical dimensions of chips are becoming smaller and smaller. However, due to the optical proximity effect, deviations occur between the lithographic pattern and the pattern on the photomask, which seriously affects the chip yield. Optical proximity correction (OPC) has become the main means to solve this problem.
[0003] Static Random Access Memory (SRAM) patterns occupy a large area on the pattern mask, and due to their high pattern repeatability, it is difficult to detect non-standard patterns in customer designs through manual inspection. OPC (Optical Process Control) then corrects these patterns, but even if no errors are found during correction, it can still lead to a loss of product yield or even scrap. Furthermore, existing SRAM pattern matching technology, such as Mentor's pattern matching technology, is encrypted and requires licenses. When many products are published online, license congestion occurs, affecting product delivery speed. Therefore, it is essential to propose an SRAM pattern inspection method that can solve this problem. Summary of the Invention
[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an SRAM marker graphic detection method to solve the problem that product delivery speed is affected by insufficient resources.
[0005] To achieve the above and other related objectives, the present invention provides a method for detecting SRAM marker images, the method comprising:
[0006] Step 1) Obtain the original design data of the chip layout at all levels, and establish an SRAM graphics library for the repeating units of the layout accordingly, and use the smallest repeating unit as the standard SRAM graphics of the SRAM graphics library.
[0007] Step 2) Obtain all SRAM marker patterns under the original design data of all levels of chip layout, wherein the SRAM marker patterns are rectangles;
[0008] Step 3) Divide the SRAM marker pattern into at least one region and select a pre-detection region. Match the sub-cell pattern located in the pre-detection region with each of the standard SRAM patterns to determine whether to detect the SRAM marker pattern. If the determination result is no, the SRAM marker pattern is not detected. If the determination result is yes, find the target standard SRAM pattern and determine the initial matching position based on the target standard SRAM pattern.
[0009] Step 4) Match the sub-cell graphics of the SRAM marker graphics along the first direction with the target standard SRAM graphic at the initial matching position with the first preset step size. After all the sub-cell graphics in the first direction are matched, if all the sub-cell graphics in the first direction match the target standard SRAM graphic, all the sub-cell graphics are treated as a whole to form a reconstructed standard SRAM graphic.
[0010] Step 5) Match the sub-cell patterns of the SRAM marker pattern with the reconstructed standard SRAM pattern along the second direction at a second preset step size;
[0011] Step 6) Output the OPC difference of each sub-cell pattern that has been matched in the SRAM marker pattern;
[0012] Step 7) Repeat steps 3) to 6) to complete the detection of all the SRAM marker patterns.
[0013] Optionally, in step 3), the SRAM marker pattern is divided into multiple regions, and the pre-detection region includes the upper left corner region and the center region of the SRAM marker pattern.
[0014] Optionally, in step 3), the method for determining whether to detect the SRAM marker graphic includes: determining whether there is a standard SRAM graphic in the SRAM graphic library that matches the sub-graphic unit located in the upper left corner region or the center region; if the determination result is no, the SRAM marker graphic is not detected; if the determination result is yes, the SRAM marker graphic is detected, the target standard SRAM graphic is found, and the initial matching position is determined.
[0015] Optionally, the method for finding the target standard SRAM pattern and determining the initial matching position includes: shifting the upper left vertex of each standard SRAM pattern to the upper left corner vertex of the upper left region, and starting from this point, sliding along the first direction and the second direction with a third preset step size to match the sub-cell pattern; if there is a standard SRAM pattern that matches the sub-cell pattern, the matching standard SRAM pattern is the target standard SRAM pattern, and the position of the first sub-target pattern that matches the target standard SRAM pattern is the initial matching position of the SRAM marker pattern; if there is no standard SRAM pattern that matches the sub-cell pattern located in the upper left region, the target standard SRAM pattern is found using the sub-cell pattern in the center region, and the initial matching position is determined.
[0016] Optionally, the method for finding the target standard SRAM graphic and determining the initial matching position using the sub-cell graphics of the central region is as follows: the upper left vertex of each standard SRAM graphic is shifted to the upper left corner vertex of the central region, and starting from this point, it slides along the first direction and the second direction with the third preset step size to match the sub-cell graphics. If there is a standard SRAM graphic that matches the sub-cell graphic, the matching standard SRAM graphic is the target standard SRAM graphic, and the position of the first sub-target graphic that matches the target standard SRAM graphic is the initial matching position of the SRAM marker graphic.
[0017] Optionally, the third preset step size is 1 / P, where P is the precision of reading GDS data.
[0018] Optionally, in step 4), the first preset step size is the length of the target standard SRAM pattern.
[0019] Optionally, in step 5), the second preset step size is the height of the target standard SRAM graphic.
[0020] Optionally, the SRAM graphics library includes the type, height, and length of each of the standard SRAM graphics.
[0021] Optionally, the attributes of the SRAM marker graphic include coordinates and type.
[0022] Optionally, the length and height of the SRAM marker graphic are obtained based on the coordinates of the SRAM marker graphic.
[0023] Optionally, for the SRAM marker pattern that can be detected, if there is a sub-cell pattern in the SRAM marker pattern that does not match the target standard SRAM pattern, then the sub-cell pattern is a non-standard SRAM pattern, and in step 6), the type of the non-standard SRAM pattern is also output.
[0024] Optionally, the first direction is the X direction and the second direction is the Y direction.
[0025] As described above, the SRAM marker pattern detection method of the present invention detects SRAM marker patterns in the layout by using a sliding window (sliding in the X and Y directions with a preset step size). This can identify unreasonable SRAM designs in the mask, thereby reducing the risk of scrapping the mask during production. Moreover, this method can solve the problem of insufficient existing software licenses and improve delivery speed. Attached Figure Description
[0026] Figure 1 The flowchart shown is a flowchart of the SRAM marker graphic detection method of the present invention.
[0027] Figure 2 The diagram shows a standard SRAM pattern included in the SRAM library of this invention.
[0028] Figure 3 The diagram shown is a schematic representation of the SRAM marker pattern of the present invention.
[0029] Figure 4 The diagram shown is a schematic representation of the SRAM marker graphic region division according to the present invention.
[0030] Figure 5 The image shown is an enlarged view of the upper left corner region A1 or the central region A2 of this invention.
[0031] Figure 6 The diagram shows the matching process based on a sliding window according to the present invention. Detailed Implementation
[0032] 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.
[0033] Please see Figures 1 to 6It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Although the illustrations only show components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation, the shape, quantity and proportion of each component in the actual implementation can be arbitrarily changed, and the layout of the components may also be more complex.
[0034] like Figure 1 As shown, this embodiment provides a method for detecting SRAM marker graphics, the method comprising:
[0035] Step 1) Obtain the original design data of the chip layout at all levels, and establish an SRAM graphics library for the repeating units of the layout accordingly, and use the smallest repeating unit as the standard SRAM graphics of the SRAM graphics library.
[0036] Step 2) Obtain all SRAM marker patterns under the original design data of all levels of chip layout, wherein the SRAM marker patterns are rectangles;
[0037] Step 3) Divide the SRAM marker pattern into at least one region and select a pre-detection region. Match the sub-cell pattern located in the pre-detection region with each of the standard SRAM patterns to determine whether to detect the SRAM marker pattern. If the determination result is no, the SRAM marker pattern is not detected. If the determination result is yes, find the target standard SRAM pattern and determine the initial matching position based on the target standard SRAM pattern.
[0038] Step 4) Match the sub-cell graphics of the SRAM marker graphics along the first direction with the target standard SRAM graphic at the initial matching position with the first preset step size. After all the sub-cell graphics in the first direction are matched, if all the sub-cell graphics in the first direction match the target standard SRAM graphic, all the sub-cell graphics are treated as a whole to form a reconstructed standard SRAM graphic.
[0039] Step 5) Match the sub-cell patterns of the SRAM marker pattern with the reconstructed standard SRAM pattern along the second direction at a second preset step size;
[0040] Step 6) Output the OPC difference of each sub-cell pattern that has been matched in the SRAM marker pattern;
[0041] Step 7) Repeat steps 3) to 6) to complete the detection of all the SRAM marker patterns.
[0042] The following is a detailed explanation of each step.
[0043] In step 1), the original design data of the chip layout at all levels is obtained, and an SRAM graphics library is established for the repeating units of the layout. The smallest repeating unit is used as the standard SRAM graphic of the SRAM graphics library.
[0044] Specifically, the SRAM graphics library includes the type, height, and length of each of the standard SRAM graphics.
[0045] Figure 2 Three different types of the standard SRAM patterns are shown, each of which is rectangular: type_1 (length l1, height h1), type_2 (length l2, height h2), and type_n (length l1, height h1). n The height is h n In this embodiment, the orientation of the standard SRAM pattern includes 0 degrees, 90 degrees, 180 degrees, and 270 degrees. The standard SRAM patterns in the SRAM pattern library are generated by extracting pattern data and can be updated in real time as needed.
[0046] In step 2), all SRAM marker patterns under the original design data of all layers of chip layout are obtained, wherein the SRAM marker patterns are rectangles.
[0047] Specifically, the attributes of the SRAM marker graphic include coordinates and type.
[0048] In this embodiment, the coordinates of the SRAM marker graphic are obtained using commands in Mentor's drv language, and corresponding coordinate data {C1, C2, ... Cn} = {{(x1, y1)(x2, y2), T1}{(x3, y3)(x4, y4), T2}...{(x... (2n-1) y (2n-1) (x) 2n y 2n ), T n}}, where (x (2n-1) y (2n-1) (x) represents the coordinates of the lower left corner of the SRAM marker graphic. 2n y 2n T represents the coordinates of the upper right corner of the SRAM marker graphic. n Indicates the type of the SRAM marker graphic (e.g.) Figure 3 (As shown).
[0049] Specifically, the length and height of the SRAM marker graphic are obtained based on its coordinates.
[0050] In this embodiment, the height H and length L of the SRAM marker graphic are calculated based on the coordinates of its lower left and upper right corners. The length L is:
[0051] L = y 2n -y (2n-1)
[0052] The height H is:
[0053] H = x 2n -x (2n-1)
[0054] Based on the obtained length and height values, it can be determined how many steps the target standard SRAM graphic needs to move in each direction.
[0055] In step 3), the SRAM marker pattern is divided into at least one region, and a pre-detection region is selected. The sub-cell pattern located in the pre-detection region is matched with each of the standard SRAM patterns to determine whether the SRAM marker pattern should be detected. If the determination result is no, the SRAM marker pattern is not detected. If the determination result is yes, the target standard SRAM pattern is found, and the initial matching position is determined according to the target standard SRAM pattern.
[0056] In this embodiment, when the SRAM marker pattern is relatively small and can only be divided into one region, then that region is the SRAM marker pattern itself, and the pre-detection region is the SRAM marker pattern itself.
[0057] Specifically, in step 3), the SRAM marker pattern is divided into multiple regions, and the pre-detection region includes the upper left corner region and the center region of the SRAM marker pattern.
[0058] like Figure 4 As shown, in this embodiment, the SRAM marker pattern is divided into 9 regions. The upper left region A1 and the center region A2 are taken as the pre-detection region. In this embodiment, the SRAM marker pattern can be determined to be detected by the sub-target patterns located in the two regions A1 and A2.
[0059] Specifically, in step 3), the method for determining whether to detect the SRAM marker graphic includes: determining whether there is a standard SRAM graphic in the SRAM graphic library that matches the sub-graphic unit located in the upper left corner region or the center region; if the determination result is no, the SRAM marker graphic is not detected; if the determination result is yes, the SRAM marker graphic is detected, the target standard SRAM graphic is found, and the initial matching position is determined.
[0060] In this embodiment, if no standard SRAM graphic in the SRAM graphic library matches the sub-target graphic in the upper left corner region A1 and the center region A2 of the SRAM marker graphic, then the entire SRAM marker graphic is no longer detected, and an error message is output; if a standard SRAM graphic matches a sub-graphic unit located in the upper left corner region, then the SRAM marker graphic is detected; if no standard SRAM graphic matches a sub-unit graphic located in the upper left corner region, but a standard SRAM graphic matches a sub-unit graphic located in the center region, then the SRAM marker graphic is still detected.
[0061] More specifically, the method for finding the target standard SRAM pattern and determining the initial matching position includes: shifting the upper left vertex of each standard SRAM pattern to the upper left corner vertex of the upper left region, and starting from this point, sliding along the first and second directions with a third preset step size to match the sub-unit pattern; if there is a standard SRAM pattern that matches the sub-unit pattern, the matching standard SRAM pattern is the target standard SRAM pattern, and the position of the first sub-target pattern that matches the target standard SRAM pattern is the initial matching position of the SRAM marker pattern; if there is no standard SRAM pattern that matches the sub-unit pattern located in the upper left region, the target standard SRAM pattern is found using the sub-unit pattern in the central region, and the initial matching position is determined.
[0062] More specifically, the method for finding the target standard SRAM pattern and determining the initial matching position using the sub-unit pattern of the central region is as follows: the upper left vertex of each standard SRAM pattern is shifted to the upper left corner vertex of the central region, and from there, it slides along the first and second directions with the third preset step size to match the sub-unit pattern. If there is a standard SRAM pattern that matches the sub-unit pattern, the matching standard SRAM pattern is the target standard SRAM pattern, and the position of the first sub-target pattern that matches the target standard SRAM pattern is the initial matching position of the SRAM marker pattern.
[0063] As an example, the third preset step size is 1 / P, where P is the precision of reading GDS data.
[0064] Figure 5A schematic diagram of the upper left corner region A1 or the center region A2 is shown. The first direction is the X direction, and the second direction is the Y direction. The target standard SRAM pattern slides in the X direction with the third preset step size 1 / P (a grid point in the diagram), and then slides in the Y direction with the third preset step size 1 / P, thereby finding the first sub-target pattern that matches it in the upper left corner region A1 or the center region A2. The position of the first sub-target pattern is taken as the initial matching position, and the detection of the entire SRAM mark pattern begins from there.
[0065] In step 4), the target standard SRAM graphic at the initial matching position is matched with the sub-cell graphics of the SRAM marker graphic along the first direction with a first preset step size. After all the sub-cell graphics in the first direction are matched, if all the sub-cell graphics in the first direction match the target standard SRAM graphic, all the sub-cell graphics are treated as a whole to form a reconstructed standard SRAM graphic.
[0066] Specifically, the first preset step size is the length of the target standard SRAM pattern.
[0067] Specifically, the first direction is the X direction, and the second direction is the Y direction.
[0068] like Figure 6 As shown, in this embodiment, after determining the initial matching position, the target standard SRAM pattern is slid along the X direction according to its length l1 to match the sub-target pattern in the X direction. At this time, the length l1 is 3 / P, which is the 3 grid points in the figure. In this embodiment, when matching the sub-cell pattern in the first row along the first direction, if any sub-cell pattern does not match the target standard SRAM pattern, the matching continues along the first direction from the sub-cells in the second row until all sub-cells in a certain row match the target standard SRAM pattern. At this point, the reconstructed standard SRAM pattern is obtained.
[0069] In step 5), the reconstructed standard SRAM pattern is matched with the sub-cell pattern of the SRAM pattern along the second direction with a second preset step size.
[0070] Specifically, in step 5), the second preset step size is the height of the target standard SRAM graphic.
[0071] In this embodiment, the reconstructed standard SRAM graphic slides downward along the Y direction to match the sub-target graphic, with a step size h1 = 4 / P, which is 4 grid points.
[0072] In step 6), the OPC difference of each sub-cell pattern that has been matched in the SRAM marker pattern is output.
[0073] Specifically, for the SRAM marker pattern that can be detected, if there is a sub-cell pattern in the SRAM marker pattern that does not match the target standard SRAM pattern, then the sub-cell pattern is a non-standard SRAM pattern. In step 6), the type of the non-standard SRAM pattern is also output.
[0074] In this embodiment, if a sub-cell pattern in the SRAM marker pattern does not match the target standard SRAM pattern, then the sub-cell pattern is a non-standard SRAM pattern. That is, the SRAM marker pattern includes both sub-cell patterns that match the target standard SRAM pattern and sub-cell patterns that do not match it, and the sub-target patterns that do not match the target standard SRAM pattern are non-standard SRAM patterns. In this embodiment, the type of output non-standard SRAM pattern refers to information where the output non-standard SRAM pattern does not belong to type_1, type_2, or type_n.
[0075] In step 7), steps 3) to 6) are repeated to complete the detection of all the SRAM marker patterns.
[0076] In summary, the SRAM marker pattern detection method of the present invention, by employing a sliding window approach (sliding in the X and Y directions with a preset step size) to detect SRAM marker patterns in the layout, can identify unreasonable SRAM designs in the mask, thereby reducing the risk of mask scrapping during production. Furthermore, it can address the issue of insufficient software licenses in existing technologies, improving delivery speed. Moreover, this method can identify potential risk patterns during OPC correction, reducing the risk of low product yield due to OPC correction. Therefore, the present invention effectively overcomes the various shortcomings of existing technologies and has high industrial applicability.
[0077] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person 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.
Claims
1. A method for detecting SRAM marker images, characterized in that, The method includes: Step 1) Obtain the original design data of the chip layout at all levels, and establish an SRAM graphics library for the repeating units of the layout accordingly, and use the smallest repeating unit as the standard SRAM graphics of the SRAM graphics library. Step 2) Obtain all SRAM marker patterns under the original design data of all levels of chip layout, wherein the SRAM marker patterns are rectangles; Step 3) Divide the SRAM marker pattern into at least one region and select a pre-detection region. Match the sub-cell pattern located in the pre-detection region with each of the standard SRAM patterns to determine whether to detect the SRAM marker pattern. If the determination result is no, the SRAM marker pattern is not detected. If the determination result is yes, find the target standard SRAM pattern and determine the initial matching position based on the target standard SRAM pattern. Step 4) Match the sub-cell graphics of the SRAM marker graphics along the X direction with the target standard SRAM graphic at the initial matching position with the first preset step size. After all the sub-cell graphics in the X direction are matched, if all the sub-cell graphics in the X direction match the target standard SRAM graphic, all the sub-cell graphics are treated as a whole to form a reconstructed standard SRAM graphic. Step 5) Match the sub-cell patterns of the SRAM marker pattern with the reconstructed standard SRAM pattern along the Y direction at a second preset step size; Step 6) Output the OPC difference of each of the sub-cell graphics that have been matched in the SRAM marker graphics; Step 7) Repeat steps 3) to 6) to complete the detection of all the SRAM marker patterns.
2. The SRAM marker pattern detection method according to claim 1, characterized in that, In step 3), the SRAM marker pattern is divided into multiple regions, and the pre-detection region includes the upper left corner region and the center region of the SRAM marker pattern.
3. The SRAM marker pattern detection method according to claim 2, characterized in that, In step 3), the method for determining whether to detect the SRAM marker graphic includes: determining whether there is a standard SRAM graphic in the SRAM graphic library that matches the sub-cell graphic located in the upper left corner region or the center region; if the determination result is no, the SRAM marker graphic is not detected; if the determination result is yes, the SRAM marker graphic is detected, the target standard SRAM graphic is found, and the initial matching position is determined.
4. The SRAM marker pattern detection method according to claim 3, characterized in that, The method for finding the target standard SRAM pattern and determining the initial matching position includes: shifting the upper left vertex of each standard SRAM pattern to the upper left corner vertex of the upper left region, and starting from this point, sliding along the X and Y directions with a third preset step size to match the sub-cell pattern; if there is a standard SRAM pattern that matches the sub-cell pattern, the matching standard SRAM pattern is the target standard SRAM pattern, and the position of the first sub-cell pattern that matches the target standard SRAM pattern is the initial matching position of the SRAM marker pattern; if there is no standard SRAM pattern that matches the sub-cell pattern located in the upper left region, the target standard SRAM pattern is found using the sub-cell pattern in the center region, and the initial matching position is determined.
5. The SRAM marker pattern detection method according to claim 4, characterized in that, The method for finding the target standard SRAM pattern and determining the initial matching position using the sub-cell pattern of the central region is as follows: the upper left vertex of each standard SRAM pattern is offset to the upper left corner vertex of the central region, and starting from this point, it slides along the X and Y directions with the third preset step size to match the sub-cell pattern. If there is a standard SRAM pattern that matches the sub-cell pattern, the matching standard SRAM pattern is the target standard SRAM pattern, and the position of the first sub-cell pattern that matches the target standard SRAM pattern is the initial matching position of the SRAM marker pattern.
6. The SRAM marker pattern detection method according to claim 5, characterized in that, The third preset step size is 1 / P, where P is the precision of reading GDS data.
7. The SRAM marker pattern detection method according to claim 1, characterized in that, In step 4), the first preset step size is the length of the target standard SRAM pattern.
8. The SRAM marker pattern detection method according to claim 1, characterized in that, In step 5), the second preset step size is the height of the target standard SRAM graphic.
9. The SRAM marker pattern detection method according to claim 1, characterized in that, The SRAM graphics library includes the type, height, and length of each of the standard SRAM graphics.
10. The SRAM marker pattern detection method according to claim 1, characterized in that, The attributes of the SRAM marker graphic include coordinates and type.
11. The SRAM marker pattern detection method according to claim 10, characterized in that, The length and height of the SRAM marker graphic are obtained from its coordinates.
12. The SRAM marker pattern detection method according to claim 1, characterized in that, For the SRAM marker pattern that can be detected, if there is a sub-cell pattern in the SRAM marker pattern that does not match the target standard SRAM pattern, then the sub-cell pattern is a non-standard SRAM pattern. In step 6), the type of the non-standard SRAM pattern is also output.