A method and device for calculating the probability of through-hole bridge defects

Abstract

The present invention discloses a method and device for calculating the probability of a via bridge defect. The method includes: obtaining a first via and a second via in a two-layer photolithography mask pattern under a double exposure process, wherein the position of the first via fluctuates along a preset direction within an overlay error range, and the position of the second via is fixed; dividing the positional relationships between the first via and the second via; calculating the distance between the first via and the second via in each positional relationship; obtaining a threshold distance for a bridge defect under the double exposure process; determining a safe interval for each positional relationship based on the threshold distance and the distance between the first via and the second via in each positional relationship; and determining the probability of a via bridge defect based on the Gaussian probability density distribution of the overlay error and the safe intervals for each positional relationship. The present invention can quickly and accurately calculate the probability of a via bridge defect.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method and device for calculating the probability of a through-hole bridge defect. Background Art

[0002] As minimum feature sizes shrink, the introduction of double patterning (DPT) has pushed the physical limits of photolithography. In logic circuit manufacturing, lithography-etch-lithography-etch (LELE) is the most commonly used double patterning technique. However, in practice, overlay errors and line width (CD) variations can cause via position shifts, leading to via bridging defects during LELE double patterning. Summary of the Invention

[0003] The present invention provides a method and device for calculating the probability of a through-hole bridge defect, which can quickly and accurately calculate the probability of a through-hole bridge defect.

[0004] According to one aspect of the present invention, a method for calculating the probability of a via bridge defect is provided, comprising:

[0005] Acquire a first through hole and a second through hole of two layers of photolithography mask layouts under a double exposure process, wherein the position of the first through hole fluctuates along a preset direction within an overlay error range, and the position of the second through hole is fixed; wherein the first through hole is a through hole pattern of the first layer of photolithography mask layout, and the second through hole is a through hole pattern of the second layer of photolithography mask layout;

[0006] Determine the positional relationship between the first through hole and the second through hole;

[0007] Obtain the threshold distance of bridge defects under double patterning process;

[0008] Determine, based on the threshold distance and the minimum distance between the first through hole and the second through hole in each position relationship, a position point in each position relationship where the minimum distance is greater than the threshold distance;

[0009] Determine the safe intervals in different position relationships based on the position points in each position relationship whose minimum distance is greater than the threshold distance;

[0010] The probability of a via bridging defect is determined based on the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships.

[0011] Optionally, dividing the positional relationship between the first through hole and the second through hole includes:

[0012] Taking the first through hole as the origin, the second through holes are located in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant of the first through hole.

[0013] Optionally, determining a position point in each position relationship where the minimum distance is greater than the threshold distance based on the threshold distance and the minimum distance between the first through hole and the second through hole in each position relationship includes:

[0014] Taking the first through hole as the origin, when the second through hole is located in the first quadrant, the second quadrant, the third quadrant, or the fourth quadrant of the first through hole, in each quadrant, respectively calculating the minimum distance between the position of the first through hole and the second through hole each time it fluctuates along the preset direction;

[0015] According to the comparison between the minimum distance and the threshold distance, the position point whose minimum distance in each position relationship is greater than the threshold distance is determined.

[0016] Optionally, determining the safety intervals in different position relationships based on the position points in each position relationship whose minimum distance is greater than the threshold distance includes:

[0017] Determine the safe interval in each quadrant based on the position points in each position relationship whose minimum distance is greater than the threshold distance;

[0018] The intersection of the safety intervals in each quadrant is taken to determine the safety intervals in different position relationships.

[0019] Optionally, determining a safe interval in each quadrant based on the position points whose minimum distance in each position relationship is greater than a threshold distance includes:

[0020] The safe interval in each quadrant is determined by the dichotomy method based on the position points in each position relationship whose minimum distance is greater than the threshold distance.

[0021] Optionally, the probability of a via bridging defect occurring is determined based on the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships, including:

[0022] Based on the Gaussian probability density distribution of the overlay error and the safety interval in different position relationships as the integration area, an integral operation is performed to determine the probability of no through-hole bridge defects.

[0023] The probability of a via bridge defect occurring is determined based on the probability of no via bridge defect occurring.

[0024] Optionally, the position of the first through hole fluctuates along a preset direction within an overlay error range, including:

[0025] According to the Gaussian probability density distribution of the overlay error, the position of the first through hole corresponds to a movable range in a preset direction.

[0026] According to another aspect of the present invention, there is provided a device for calculating the probability of a via bridge defect, comprising:

[0027] A first acquisition module is configured to acquire a first through-hole and a second through-hole of two layers of photolithography mask layouts in a double exposure process, wherein the position of the first through-hole fluctuates along a preset direction within an overlay error range, and the position of the second through-hole is fixed; wherein the first through-hole is a through-hole pattern of the first layer of photolithography mask layout, and the second through-hole is a through-hole pattern of the second layer of photolithography mask layout;

[0028] A dividing module, used for dividing the positional relationship between the first through hole and the second through hole;

[0029] A second acquisition module is used to obtain a threshold distance of a bridge defect in a double exposure process;

[0030] A first determining module is configured to determine a position point in each position relationship where the minimum distance is greater than the threshold distance based on the threshold distance and the minimum distance between the first through hole and the second through hole in each position relationship;

[0031] A second determining module is configured to determine a safety interval in different position relationships based on a position point in each position relationship whose minimum distance is greater than a threshold distance;

[0032] The third determination module is used to determine the probability of a through-hole bridge defect occurring according to the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships.

[0033] Optionally, the partitioning modules include:

[0034] Taking the first through hole as the origin, the second through holes are located in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant of the first through hole.

[0035] Optionally, the first determining module includes:

[0036] a calculation submodule, configured to calculate, with the first through hole as the origin, a minimum distance between the position of the first through hole and the second through hole when the second through hole is located in the first quadrant, the second quadrant, the third quadrant, or the fourth quadrant of the first through hole, in each quadrant;

[0037] The determination submodule is used to determine the position point whose minimum distance is greater than the threshold distance in each position relationship based on the comparison between the minimum distance and the threshold distance.

[0038] The method for calculating the probability of a via bridge defect provided by the technical solution of an embodiment of the present invention includes: obtaining a first via and a second via in two layers of a photolithography mask layout under a double exposure process, wherein the position of the first via fluctuates along a preset direction within an overlay error range, and fixing the position of the second via; wherein the first via is a via pattern in the first layer of the photolithography mask layout, and the second via is a via pattern in the second layer of the photolithography mask layout; dividing the positional relationship between the first via and the second via; obtaining a threshold distance for a bridge defect under the double exposure process; determining, based on the threshold distance and the minimum distance between the first via and the second via in each positional relationship, a position point at which the minimum distance in each positional relationship exceeds the threshold distance; determining a safe interval in different positional relationships based on the position point at which the minimum distance in each positional relationship exceeds the threshold distance; and determining the probability of a via bridge defect based on the Gaussian probability density distribution of the overlay error and the safe intervals in different positional relationships. By introducing the overlay error into the calculation of the total safe interval, the embodiment of the present invention can make the method for calculating the probability of a via bridge defect more accurate, rapid, and efficient.

[0039] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 This is a schematic diagram of the splitting of the LELE process layout in a double exposure process provided by the present invention.

[0042] Figure 2 This is a LELE photolithography process flow chart provided by the present invention.

[0043] Figure 3 This is a schematic diagram of the position where a through hole provided by the present invention is most likely to have a bridging defect.

[0044] Figure 4 This is a flow chart of a method for calculating the probability of a through-hole bridge defect provided in Example 1 of the present invention.

[0045] Figure 5 This is a schematic diagram of a first through hole and a second through hole provided in the first embodiment of the present invention.

[0046] Figure 6This is a schematic diagram of the positional relationship between a first through hole and a second through hole provided in the first embodiment of the present invention.

[0047] Figure 7 This is a flowchart of determining a safety interval provided by the first embodiment of the present invention.

[0048] Figure 8 Schematic diagram of a device for calculating the probability of a through-hole bridge defect provided by a second embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0050] It should be noted that the terms "first," "second," and the like in the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0051] Figure 1 This is a schematic diagram of the splitting of the LELE process layout in a double exposure process provided by the present invention. Figure 2 This is a LELE lithography process flow chart provided by the present invention, refer to Figure 1 The left picture is the graphic layer that needs to be etched. The graphic layer that needs to be etched is divided into two layouts. The two graphics in the middle are mask A and mask B respectively. The right picture shows the patterns after the two layouts are etched. Figure 2Figure (a) shows the first photolithography process based on mask A, Figure (b) shows the first etching process based on mask A, Figure (c) shows the second photolithography process based on mask B, Figure (d) shows the second etching process based on mask B, and Figure (e) shows the final structure after the LELE process. The applicant found that in the implemented process, the combined effects of the via process, the existence of overlay error, the pattern offset caused by the mask three-dimensional effect (M3D), and the defects of the optical proximity effect correction strategy will lead to via bridging defects under the double exposure of LELE. The key to the success of advanced nodes under double exposure depends on the manufacturer's ability to meet the extremely strict edge placement error (EPE) budget, and the line width (CD) variation and overlay error are the factors that cause bridging defects in double exposure (DPT), among which the impact of overlay error is very critical.

[0052] In traditional technical solutions, the technology used by mainstream software is based on a layout corrected for the optical proximity effect, using a lithography model for calculation to obtain the contour graphic after lithography. Based on the contour graphic after lithography obtained by simulation, the corresponding etching deviation in the process is subtracted to obtain the simulated contour graphic after etching. The etched contour graphics of the two split layouts are merged into the same layer, and then the distance between the graphics is detected. The software will determine a distance threshold based on the actual chip manufacturing process capabilities. A distance below this threshold is considered to be a short circuit, and the two through-holes involved in this distance will be highlighted for optimization of the lithography process or design layout.

[0053] Applicants have discovered that at advanced nodes, at extreme dimensions, process fluctuations due to overlay error have a significant and non-negligible impact on final yield. Overlay error is a crucial factor. Simply setting a distance threshold without considering the statistical characteristics of overlay error to determine whether a bridge or short circuit exists is insufficient to support the final defect determination and reduces the accuracy of the determination. Furthermore, traditional methods for calculating the probability of success of the final circuit layout require the Monte Carlo method, which is extremely time-consuming and cannot be applied in large-scale integrated circuit manufacturing.

[0054] Specifically, during the layout design process, the applicant will try to avoid the vias facing each other within a very narrow distance by optimizing the layout and design rules of the vias, avoiding overly dense wiring and overly long lines, so as to reduce the concentration of electric field strength. If the vias face each other within a very narrow distance, TDDB (Transient Drain to Source Breakdown) will occur to a large extent. TDDB refers to the phenomenon that the electric field strength between the drain and source of the transistor exceeds the breakdown electric field strength of the material in a short period of time, causing the transistor to fail. Therefore, Figure 3 This is a schematic diagram of the position where a through hole is most likely to have a bridging defect provided by the present invention, with reference to Figure 3 The minimum distance between vias usually occurs at the corner to corner (C2C) position, where via bridge defects are very likely to occur. Bridge defects will cause short circuit risks. Figure 3 Medium M X is the xth metal layer; V X is the through hole in the xth layer; M X+1 is the x+1th layer of metal; A is the pattern on mask A after splitting; B is the pattern on mask B after splitting; C2C is the minimum angle-to-angle distance of the through hole.

[0055] Example 1

[0056] The embodiment of the present invention provides a method for calculating the probability of a through-hole bridge defect. Figure 4 This is a flow chart of a method for calculating the probability of a through-hole bridge defect provided by the first embodiment of the present invention, with reference to Figure 4 , the calculation method of the via bridge defect probability includes:

[0057] S110. Obtain a first through hole and a second through hole of two layers of photolithography mask layouts under a double exposure process, wherein the position of the first through hole fluctuates along a preset direction within an overlay error range, and the position of the second through hole is fixed; wherein the first through hole is a through hole pattern of the first layer of photolithography mask layout, and the second through hole is a through hole pattern of the second layer of photolithography mask layout.

[0058] Exemplary, reference Figure 3, the first layer of photolithography mask layout can be mask A, the first through hole can be a through hole pattern on mask A, and the first layer of photolithography mask layout includes multiple first through holes; the second layer of photolithography mask layout can be mask B, the second through hole can be a through hole pattern on mask B, and the second layer of photolithography mask layout includes multiple second through holes. For the convenience of calculation, the second through hole is set as a fixed through hole, and the first through hole is set as a fluctuating through hole, that is, a through hole with uncertain landing point due to overlay error. In the process of self-aligned via (SAV), photolithography technology and etching technology are required. The xth layer of metal will be manufactured first, then the x+1th layer of metal will be manufactured, and then the xth layer of through hole will be manufactured on the x+1th layer of metal. At this time, since the x+1th layer of metal has been manufactured, and due to the particularity of the self-aligned through-hole process, the through-hole will be larger in the restricted direction during manufacturing, and the width of the x+1th layer of metal can limit the width of the through-hole in the restricted direction; the area restricted by metal in the SAV lithography process does not need to consider overlay error; and in the non-restricted direction in the other direction, due to the existence of overlay error, the through-hole will fluctuate in the preset direction (y direction), and its landing point position is not restricted. The overlay error range can be determined as [-3σ, 3σ] based on the Gaussian probability density distribution of the overlay error, where σ is the standard deviation of the Gaussian probability density distribution. Figure 5 is a schematic diagram of a first through hole and a second through hole provided in the first embodiment of the present invention, with reference to Figure 5 ViaA is the first through hole on the first layer of the photolithography mask layout, and ViaB is the second through hole on the second layer of the photolithography mask layout. When the through holes are prepared using double exposure process conditions and a self-aligned through hole lithography process is adopted, due to the existence of overlay error in the preset direction, the first through hole fluctuates due to the overlay error in the preset direction, and a bridging defect is likely to occur at the minimum angle-to-angle position.

[0059] S120 , determining the positional relationship between the first through hole and the second through hole.

[0060] Among them, any one first through hole is selected as the coordinate origin from the multiple first through holes included in the first layer photolithography mask pattern, and the second through holes around the fluctuating first through hole are divided into four quadrants according to the relative coordinate positions of the second through hole and the first through hole. For example, with the first through hole as the origin, the second through holes are located in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant of the first through hole.

[0061] S130 , obtaining a threshold distance of a bridge defect in a double exposure process.

[0062] Among them, the threshold distance is the position where the bridge defect exists between the first through hole and the second through hole. There is no bridge defect at a position greater than the threshold distance, and there is a bridge defect at a position less than or equal to the threshold distance. The threshold distance can be determined according to the through hole size and the actual process.

[0063] S140 , determining a position point in each position relationship where the minimum distance is greater than the threshold distance based on the threshold distance and the minimum distance between the first through hole and the second through hole in each position relationship.

[0064] The position of the first through hole fluctuates along a preset direction within an overlay error range, and the minimum distance between the position of the first through hole after each fluctuation and the second through hole is calculated. The minimum distance is compared with the threshold distance, and the position points of the first through hole in each position relationship where the minimum distance is greater than the threshold distance are determined. For example, in the first quadrant, each time the first through hole moves one position along the preset direction, the minimum distance between the first through hole and the second through hole is measured. If the minimum distance is greater than the threshold distance, the position of the first through hole is confirmed to be a safe position point. If the minimum distance is less than or equal to the threshold distance, the position of the first through hole is confirmed to be a failed position point, and a bridging defect may occur, and the failed position point is filtered out.

[0065] S150 : Determine safety intervals in different positional relationships based on the position points in each positional relationship whose minimum distance is greater than a threshold distance.

[0066] Based on the position points in each position relationship whose minimum distance exceeds the threshold distance, all safe position points of the first through-holes in each quadrant whose minimum distance exceeds the threshold distance are determined. The safe position points of the first through-holes in each quadrant are grouped into a safe interval for each quadrant. The safe intervals in each quadrant are then intersected to determine the total safe interval for different position relationships. By calculating the safe interval in one position relationship, the same method is used to find the safe intervals in other regions. The total safe interval is calculated as the intersection of the safe intervals, which allows for the rapid demarcation of the safe range within the calculation area.

[0067] S160 , determining the probability of a through-hole bridge defect occurring based on the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships.

[0068] Among them, the fluctuation of the overlay error obeys the Gaussian distribution, and the overlay error follows the Gaussian probability density distribution. According to the position point where the minimum distance in each position relationship is greater than the threshold distance, the safe interval in different position relationships is determined as the integral area. The integral operation is performed to obtain the probability that the through hole in the target safe area will not be bridged / short-circuited. Based on the probability of no bridge / short-circuit, the probability of a through hole bridge defect can be determined. In the subsequent process, it is possible to directly determine whether there is a bridge defect between two through holes, which can quantitatively guide layout design, lithography process selection and related parameters, and can quantitatively compensate for negative effects caused by mask three-dimensional effects or overlay errors.

[0069] The method for calculating the probability of a via bridge defect provided by the technical solution of an embodiment of the present invention includes: obtaining a first via and a second via in two layers of a photolithography mask layout under a double exposure process, wherein the position of the first via fluctuates along a preset direction within an overlay error range, and fixing the position of the second via; wherein the first via is a via pattern in the first layer of the photolithography mask layout, and the second via is a via pattern in the second layer of the photolithography mask layout; dividing the positional relationship between the first via and the second via; obtaining a threshold distance for a bridge defect under the double exposure process; determining, based on the threshold distance and the minimum distance between the first via and the second via in each positional relationship, a position point at which the minimum distance in each positional relationship exceeds the threshold distance; determining a safe interval in different positional relationships based on the position point at which the minimum distance in each positional relationship exceeds the threshold distance; and determining the probability of a via bridge defect based on the Gaussian probability density distribution of the overlay error and the safe intervals in different positional relationships. By introducing the overlay error into the calculation of the total safe interval, the embodiment of the present invention can make the method for calculating the probability of a via bridge defect more accurate, rapid, and efficient.

[0070] Optionally, dividing the positional relationship between the first through hole and the second through hole includes: taking the first through hole as the origin, the second through hole is located in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant of the first through hole.

[0071] Among them, the second through hole at a fixed position closest to the first through hole that can fluctuate in each quadrant is screened out, and the distance between each of the second through hole and the first through hole that can fluctuate is calculated. Figure 6 This is a schematic diagram of the positional relationship between a first through hole and a second through hole provided in the first embodiment of the present invention, with reference to Figure 6ViaA is the first through hole, and the overlay error of the first through hole ViaA along the y direction can fluctuate within the range of -3σ to +3σ. ViaB1, ViaB2, ViaB3 and ViaB4 are all second through holes. ViaB1 is located in the first quadrant of ViaA, and ViaB1 is the second through hole closest to ViaA in the first quadrant; ViaB2 is located in the second quadrant of ViaA, and ViaB2 is the second through hole closest to ViaA in the second quadrant; Via_B3 is located in the third quadrant of ViaA, and ViaB3 is the second through hole closest to ViaA in the third quadrant; Via_B4 is located in the fourth quadrant of ViaA, and ViaB4 is the second through hole closest to ViaA in the fourth quadrant.

[0072] Optionally, based on the threshold distance and the minimum distance between the first through hole and the second through hole in each position relationship, the position point in each position relationship where the minimum distance is greater than the threshold distance is determined, including: taking the first through hole as the origin, when the second through hole is located in the first quadrant, the second quadrant, the third quadrant or the fourth quadrant of the first through hole, in each quadrant, respectively calculating the position where the first through hole fluctuates along the preset direction each time and the minimum distance between the second through hole; based on the comparison of the minimum distance and the threshold distance, determining the position point in each position relationship where the minimum distance is greater than the threshold distance.

[0073] Among them, the situation of the second through hole in the first quadrant is calculated. Along the preset direction of the overlay error, the movable range of the first through hole is -3σ to +3σ. Every time the first through hole moves one position along the preset direction, the minimum distance between the first through hole and the second through hole is measured. If the minimum distance is greater than the threshold distance, it is proved that the position of the first through hole is a safe position point. If the minimum distance is less than or equal to the threshold distance, it is proved that the position of the first through hole is a failure position point, and a bridging defect may occur. Thus, all the safe position points of the first through hole in the first quadrant are determined; in the same way, all the safe position points of the first through hole in the second quadrant are calculated when the second through hole is in the second quadrant; all the safe position points of the first through hole in the third quadrant when the second through hole is in the third quadrant; and all the safe position points of the first through hole in the fourth quadrant when the second through hole is in the fourth quadrant.

[0074] Optionally, based on the position points in each position relationship whose minimum distance is greater than the threshold distance, the safe intervals in different position relationships are determined, including: based on the position points in each position relationship whose minimum distance is greater than the threshold distance, the safe intervals in each quadrant are determined; and the intersection of the safe intervals in each quadrant is taken to determine the safe intervals in different position relationships.

[0075] Among them, the safe interval in each quadrant can be determined by bisection based on the position points in each position relationship whose minimum distance is greater than the threshold distance. The safe intervals in each quadrant are intersected to determine the safe intervals in different position relationships. Figure 7 This is a flowchart of determining a safety interval provided by the first embodiment of the present invention. Figure 7 , divide the safety interval of the first quadrant into Ф1, the safety interval of the second quadrant into Ф2, the safety interval of the third quadrant into Ф3, and the safety interval of the fourth quadrant into Ф4, then the total safety interval is Ф=Ф1∩Ф2∩Ф3∩Ф4, compare the Ф of the horizontal coordinates in Ф1, Ф2, Ф3, and Ф4 1min , Ф 2min , Ф 3min and Φ 4min , select the maximum value Ф max As the abscissa of the total safety interval; compare the ordinates of Ф1, Ф2, Ф3, and Ф4 1max , Ф 2man , Ф 3max and Φ 4max , select the minimum value Ф min As the vertical coordinate of the total safety interval, the total safety interval is determined.

[0076] Specifically, the self-aligned through-hole under the double exposure process in the embodiment of the present invention takes into account the process variations of the profile and overlay error after exposure and etching in the non-restricted direction (i.e., the preset direction), and uses the binary search method to find the critical position points in each quadrant that are greater than or equal to the threshold distance, thereby determining the safe interval in each quadrant on the two-layer photolithography mask layout, and then uses the same method to find the safety critical position points and their safe intervals in other quadrants in the area to be calculated. The total safe interval in the calculation area is the intersection of the safe intervals in each quadrant, so that the safe range within the calculation area can be quickly delineated.

[0077] Optionally, the probability of a through-hole bridging defect occurring is determined based on the Gaussian probability density distribution of the overlay error and the safety intervals in different positional relationships, including: performing an integral operation based on the Gaussian probability density distribution of the overlay error and the safety intervals in different positional relationships as the integral region to determine the probability that the through-hole bridging defect does not occur; and determining the probability of a through-hole bridging defect occurring based on the probability that the through-hole bridging defect does not occur.

[0078] According to the Gaussian probability density distribution of the overlay error, the corresponding integral interval can be determined according to the positional relationship between the first through hole and the second through hole, so that the probability of a bridging defect between the first through hole and the second through hole can be quickly and accurately calculated.

[0079] Optionally, the position of the first through hole fluctuates along a preset direction within an overlay error range, including: a movable range corresponding to the position of the first through hole in the preset direction according to a Gaussian probability density distribution of the overlay error.

[0080] The overlay error range can be determined as [-3σ, 3σ] according to the Gaussian probability density distribution of the overlay error, where σ is the standard deviation of the Gaussian probability density distribution, and the first through hole moves along [-3σ, 3σ] in the preset direction.

[0081] In the double exposure process, when using a self-aligned via lithography process, via bridging defects may occur due to the presence of overlay errors in a preset direction. The present invention further proposes a via model based on the above-mentioned embodiments. The via model includes the method for calculating the probability of via bridging defects described in any embodiment of the present invention. This model can quantitatively calculate the probability of such bridging / short-circuit defects. In subsequent processes, it can quantitatively guide layout design, lithography process selection, and related parameters, and can quantitatively compensate for negative effects caused by mask three-dimensional effects or overlay errors. The via model proposed in the embodiment of the present invention can quickly calculate the success and failure probabilities between vias, which is at least 800 times higher than the Monte Carlo method, making it more suitable for large-scale layout applications.

[0082] Example 2

[0083] The embodiment of the present invention further provides a device for calculating the probability of a through-hole bridge defect based on the above embodiment. Figure 8 is a schematic diagram of a calculation device for a through-hole bridge defect probability provided by the second embodiment of the present invention, with reference to Figure 8 , the computing device includes:

[0084] A first acquisition module 210 is configured to acquire a first through-hole and a second through-hole of two layers of photolithography mask layouts in a double exposure process, wherein the position of the first through-hole fluctuates along a preset direction within an overlay error range, and the position of the second through-hole is fixed; wherein the first through-hole is a through-hole pattern of the first layer of photolithography mask layout, and the second through-hole is a through-hole pattern of the second layer of photolithography mask layout;

[0085] A dividing module 220, configured to divide the positional relationship between the first through hole and the second through hole;

[0086] The second acquisition module 230 is used to obtain the threshold distance of the bridge defect in the double exposure process;

[0087] A first determining module 240 is configured to determine a position point in each position relationship where the minimum distance is greater than the threshold distance based on the threshold distance and the minimum distance between the first through hole and the second through hole in each position relationship;

[0088] A second determining module 250 is configured to determine safety intervals in different position relationships based on the position points in each position relationship whose minimum distance is greater than a threshold distance;

[0089] The third determination module 260 is configured to determine the probability of a via bridge defect occurring based on the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships.

[0090] Optionally, the partitioning modules include:

[0091] Taking the first through hole as the origin, the second through holes are located in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant of the first through hole.

[0092] Optionally, the first determining module includes:

[0093] a calculation submodule, configured to calculate, with the first through hole as the origin, a minimum distance between the position of the first through hole and the second through hole when the second through hole is located in the first quadrant, the second quadrant, the third quadrant, or the fourth quadrant of the first through hole, in each quadrant;

[0094] The first determining submodule is configured to determine, based on a comparison between the minimum distance and the threshold distance, a position point in each position relationship whose minimum distance is greater than the threshold distance.

[0095] Optionally, the second determining module includes:

[0096] A second determination submodule is configured to determine a safe interval in each quadrant based on the position points in each position relationship whose minimum distance is greater than a threshold distance;

[0097] The third determination submodule is used to obtain the intersection of the safety intervals in each quadrant and determine the safety intervals in different position relationships.

[0098] Optionally, the second determination submodule includes:

[0099] The safe interval in each quadrant is determined by the dichotomy method based on the position points in each position relationship whose minimum distance is greater than the threshold distance.

[0100] Optionally, the third determination module includes:

[0101] A fourth determination submodule is configured to perform an integration operation based on the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships as an integration region to determine the probability of no via bridge defect occurring;

[0102] The fifth determination submodule is configured to determine the probability of a via bridge defect occurring according to the probability of no via bridge defect occurring.

[0103] Optionally, the position of the first through hole fluctuates along a preset direction within an overlay error range, including: a movable range corresponding to the position of the first through hole in the preset direction according to a Gaussian probability density distribution of the overlay error.

[0104] The device for calculating the via bridge defect probability provided by the technical solution of the embodiment of the present invention has the same beneficial effects as the method for calculating the via bridge defect probability described in any embodiment of the present invention.

[0105] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0106] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A method for calculating the probability of a through-hole bridge defect, characterized in that: include: Acquire a first through hole and a second through hole of two layers of photolithography mask layouts in a double exposure process, wherein the position of the first through hole fluctuates along a preset direction within an overlay error range, and the position of the second through hole is fixed; wherein the first through hole is a through hole pattern of the first layer of photolithography mask layout, and the second through hole is a through hole pattern of the second layer of photolithography mask layout; Determine the positional relationship between the first through hole and the second through hole; Obtain the threshold distance of bridge defects under double patterning process; Determine, based on the threshold distance and the minimum distance between the first through hole and the second through hole in each positional relationship, a position point in each positional relationship where the minimum distance is greater than the threshold distance; Determining safety intervals in different positional relationships based on the position points in each positional relationship where the minimum distance is greater than the threshold distance; The probability of a via bridging defect is determined based on the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships.

2. The method for calculating the probability of a via bridge defect according to claim 1, wherein: Defining the positional relationship between the first through hole and the second through hole includes: Taking the first through hole as the origin, the second through holes are located in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant of the first through hole.

3. The method for calculating the probability of a via bridge defect according to claim 2, wherein: Determining, based on the threshold distance and the minimum distance between the first through hole and the second through hole in each positional relationship, a position point in each positional relationship where the minimum distance is greater than the threshold distance, includes: Taking the first through hole as the origin, when the second through hole is located in the first quadrant, the second quadrant, the third quadrant, or the fourth quadrant of the first through hole, in each quadrant, respectively calculate the minimum distance between the position of the first through hole fluctuating along the preset direction each time and the second through hole; According to the comparison between the minimum distance and the threshold distance, a position point in each position relationship where the minimum distance is greater than the threshold distance is determined.

4. The method for calculating the probability of a via bridge defect according to claim 3, wherein: Determining, based on the position points in each position relationship where the minimum distance is greater than the threshold distance, the safety intervals in different position relationships, including: Determine a safe interval in each quadrant according to the position points in each position relationship where the minimum distance is greater than the threshold distance; The intersection of the safety intervals in each quadrant is taken to determine the safety intervals in different position relationships.

5. The method for calculating the probability of a via bridge defect according to claim 4, wherein: Determining a safe interval in each quadrant according to the position points in each position relationship whose minimum distance is greater than the threshold distance includes: The safety interval in each quadrant is determined by a dichotomy method according to the position points in each position relationship where the minimum distance is greater than the threshold distance.

6. The method for calculating the probability of a via bridge defect according to claim 1, wherein: Determining the probability of the via bridging defect occurring based on the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships includes: Performing an integration operation based on the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships as an integration region to determine the probability that the through-hole bridging defect does not occur; The probability of the via bridge defect occurring is determined according to the probability of the via bridge defect not occurring.

7. The method for calculating the probability of a via bridge defect according to claim 1, wherein: The position of the first through hole fluctuates along a preset direction within an overlay error range, including: According to the Gaussian probability density distribution of the overlay error, the position of the first through hole corresponds to a movable range in a preset direction.

8. A device for calculating the probability of a through-hole bridge defect, characterized in that: include: A first acquisition module is configured to acquire a first through-hole and a second through-hole of two layers of photolithography mask layouts in a double exposure process, wherein the position of the first through-hole fluctuates along a preset direction within an overlay error range, and the position of the second through-hole is fixed; wherein the first through-hole is a through-hole pattern of the first layer of photolithography mask layout, and the second through-hole is a through-hole pattern of the second layer of photolithography mask layout; a dividing module, configured to divide the positional relationship between the first through hole and the second through hole; A second acquisition module is used to obtain a threshold distance of a bridge defect in a double exposure process; a first determining module, configured to determine, based on the threshold distance and the minimum distance between the first through hole and the second through hole in each position relationship, a position point in each position relationship where the minimum distance is greater than the threshold distance; a second determining module, configured to determine safety intervals in different positional relationships based on the position points in each positional relationship where the minimum distance is greater than the threshold distance; The third determination module is used to determine the probability of a through-hole bridge defect occurring according to the Gaussian probability density distribution of the overlay error and the safety intervals in different position relationships.

9. The device for calculating the probability of a via bridge defect according to claim 8, wherein: The division modules include: Taking the first through hole as the origin, the second through holes are located in the first quadrant, the second quadrant, the third quadrant and the fourth quadrant of the first through hole.

10. The device for calculating the probability of a via bridge defect according to claim 8, wherein: The first determination module includes: a calculation submodule, configured to calculate, with the first through hole as the origin, a minimum distance between the position of the first through hole fluctuating along a preset direction and the second through hole in each quadrant when the second through hole is located in the first quadrant, the second quadrant, the third quadrant, or the fourth quadrant of the first through hole; The determination submodule is configured to determine, based on a comparison between the minimum distance and the threshold distance, a position point in each position relationship where the minimum distance is greater than the threshold distance.

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