Defect detection method and defect detection system

Abstract

A defect detection method and defect detection system, comprising: providing a wafer, the wafer comprising a detection surface; scanning the detection surface to obtain a scanned image of the detection surface, the scanned image comprising a plurality of first unit graphics; providing a design image, the design image comprising a plurality of second unit graphics corresponding to the first unit graphics; screening the scanned image according to the design image, and removing the interfering defect unit graphics in the first unit graphics. In the technical solution of the present invention, by partially screening and removing the interfering defect unit graphics in the first unit graphics, the number of first unit graphics for subsequent detection and analysis is effectively reduced, the detection time is shortened, and the detection efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor testing, and in particular to a defect detection method and a defect detection system. Background Art

[0002] Semiconductor manufacturing technology has made great progress in recent years, and now the minimum feature size can be reduced to less than 10 nanometers, and the pattern density is higher than ever before. When semiconductor chip foundries develop next-generation technologies, especially in the early stages, more defect modes (hot spots) appear. Therefore, a method to quickly and accurately discover and analyze these weak links is urgently needed to accelerate technology development and improve yield.

[0003] However, the detection efficiency of existing defect detection methods needs to be improved. Summary of the invention

[0004] The problem solved by the present invention is to provide a defect detection method and a defect detection system, which can screen and remove some interfering defect unit patterns, effectively reduce the number of first unit patterns for subsequent detection and analysis, shorten the detection time, and thus improve the detection efficiency.

[0005] To solve the above problems, the present invention provides a defect detection method, comprising: providing a wafer, the wafer comprising a detection surface; scanning the detection surface to obtain a scanned image of the detection surface, the scanned image comprising a plurality of first unit graphics; providing a design image, the design image comprising a plurality of second unit graphics corresponding to the first unit graphics; screening the scanned image according to the design image to remove interfering defect unit graphics in the first unit graphics.

[0006] Optionally, the method for filtering the scanned image according to the design image includes: obtaining a filtering value based on measuring the design image and the scanned image; providing a filtering condition corresponding to the filtering value; judging whether each of the first unit graphics is an interference defect unit graphic according to comparing the filtering value with the filtering condition; when the first unit graphics is an interference defect unit graphic, deleting the interference defect unit graphic from the scanned image.

[0007] Optionally, the screening value includes: an overlap rate value between the first unit graphic and its corresponding second unit graphic, a characteristic size value of the second unit graphic, and a graphic spacing value of the second unit graphic.

[0008] Optionally, the screening conditions include: an overlap rate threshold, a feature size threshold, and a graphic spacing threshold.

[0009] Optionally, based on comparing the filtering value with the filtering condition, the method for determining whether each first unit graphic is an interference defective unit graphic includes: when the overlap rate value is less than or equal to the overlap rate threshold, the feature size value is greater than or equal to the feature size threshold, and the graphic spacing value is greater than or equal to the graphic spacing threshold, then determining that the first unit graphic is an interference defective unit graphic.

[0010] Optionally, the overlap ratio value is a ratio of an overlapping area of ​​the first unit graphic and the corresponding second unit graphic to an area of ​​the second unit graphic.

[0011] Optionally, the method for obtaining the overlapping area between the first unit graphic and the corresponding second unit graphic includes: overlapping and aligning the design image with the scanned image, the first unit graphic corresponding to the second unit graphic; and obtaining the overlapping area between the first unit graphic and the corresponding second unit graphic through Boolean operation.

[0012] Optionally, the graphic spacing value is a minimum spacing value between a single second unit graphic and another adjacent second unit graphic in the design image.

[0013] Optionally, the overlap rate threshold ranges from 60% to 90%.

[0014] Optionally, the method for obtaining the feature size threshold includes: providing a first magnification and a minimum feature size value specified in a design rule of the design image; the feature size threshold is the product of the minimum feature size value and the first magnification.

[0015] Optionally, the first magnification ranges from 2 to 5 times.

[0016] Optionally, the method for obtaining the graphic spacing threshold includes: providing a second magnification and a minimum spacing dimension value specified in a design rule of the design image; and the spacing dimension threshold is the product of the minimum spacing dimension value and the second magnification.

[0017] Optionally, the second magnification ranges from 2 to 5 times.

[0018] Correspondingly, the present invention also provides a defect detection system, including: a scanning unit, used to obtain a scanning image of a wafer inspection surface, the scanning image including a plurality of first unit graphics; a design image unit, used to provide a design image, the design image including a plurality of second unit graphics corresponding to the first unit graphics; a screening unit, used to screen the scanning image according to the design image, and remove interfering defect unit graphics in the first unit graphics.

[0019] Optionally, the screening unit includes: a measurement module, which obtains a screening value by measuring the design image and the scanned image; a screening condition module: used to provide screening conditions corresponding to the screening value; a judgment module, which compares the screening value with the screening condition to judge whether each of the first unit graphics is an interference defect unit graphic; and an operation module, which deletes the interference defect unit graphic from the scanned image when the first unit graphic is an interference defect unit graphic.

[0020] Optionally, the screening conditions include: an overlap rate threshold, a feature size threshold, and a graphic spacing threshold.

[0021] Optionally, the screening value includes: an overlap rate value between the first unit graphic and its corresponding second unit graphic, a characteristic size value of the second unit graphic, and a graphic spacing value of the second unit graphic.

[0022] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0023] In the defect detection method provided by the technical solution of the present invention, the scanned image is screened by designing an image, and some interfering defective unit graphics in the first unit graphics of the scanned image are screened and removed, thereby effectively reducing the number of first unit graphics for subsequent detection and analysis, shortening the detection time, and thus improving the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart of the steps of a defect detection method;

[0025] Figure 2 is a flow chart of each step of the defect detection method according to an embodiment of the present invention;

[0026] Figures 3 to 8 is a structural schematic diagram of each step of the defect detection method according to an embodiment of the present invention;

[0027] Fig. 9 It is a schematic diagram of the structure of a defect detection system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] As described in the background art, the detection efficiency of the defect detection method in the prior art needs to be improved.

[0029] Figure 1 The present invention is a flow chart of an embodiment of a defect detection method, comprising:

[0030] Step S11, providing a wafer, wherein the wafer comprises a detection surface;

[0031] Step S12, scanning the inspection surface to obtain a scanned image of the inspection surface, wherein the scanned image includes a plurality of defect unit patterns;

[0032] Step S13, detecting and analyzing the plurality of defective unit patterns in the scanned image one by one, and determining whether the defective unit patterns are interference defective unit patterns.

[0033] In the above detection method, a computer can automatically find several defective unit graphics on the wafer scanning image. However, among these defective unit graphics, only a small part of the defective unit graphics are designed defective unit graphics formed due to design reasons, and the remaining defective unit graphics are mostly interference defective unit graphics formed due to deviations in the manufacturing process. This part of the interference defective unit graphics can be changed and eliminated by adjusting the parameters in the manufacturing process. The improvement process is relatively simple and has a short cycle. The other part of the design defective unit graphics needs to be redesigned, and the improvement process is relatively complicated. Therefore, this part of the design defective unit graphics needs to be detected and separated. However, in the existing detection and analysis methods, it is still necessary to check and analyze all the defective unit graphics one by one to determine which one is actually formed due to design reasons. The process requires a large number of defective unit graphics to be detected and analyzed, which is very time-consuming, resulting in low detection efficiency.

[0034] In order to solve the above problems, the present invention provides a defect detection method and a defect detection system, which effectively reduces the number of first unit graphics for subsequent detection and analysis by partially screening and removing interfering defect unit graphics in the first unit graphics, shortens the detection time, and thus improves the detection efficiency.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0036] Figure 2 is a flow chart of a defect detection method according to an embodiment of the present invention, comprising:

[0037] Step S21, providing a wafer, wherein the wafer comprises a detection surface;

[0038] Step S22, scanning the detection surface to obtain a scanned image of the detection surface, wherein the scanned image includes a plurality of first unit patterns;

[0039] Step S23, providing a design image, wherein the design image includes a plurality of second unit graphics corresponding to the first unit graphics;

[0040] Step S24, screening the scanned image according to the design image, and removing interfering defective unit patterns in the first unit patterns.

[0041] The defect detection steps are described in detail below with reference to the accompanying drawings.

[0042] Figures 3 to 8 It is a structural schematic diagram of each step of the defect detection method according to an embodiment of the present invention.

[0043] Please refer to Figure 3 , providing a wafer 200, wherein the wafer 200 includes a detection surface.

[0044] The wafer 200 has a semiconductor structure therein, and the semiconductor structure includes an electrical interconnection structure, a gate structure, and a device structure. The inspection surface of the wafer exposes one or more top surfaces of the electrical interconnection structure, the gate structure, and the device structure.

[0045] There are defects on the top surface of the semiconductor structure exposed on the detection surface. Some of these defects are process defects caused by process deviations, and the other part are design defects generated during design. In this embodiment, what we need to obtain are design defects.

[0046] Please refer to Figure 4 , scanning the detection surface to obtain an overall scan image of the detection surface. It should be noted that, Figure 4 The scanned image 210 in the figure is a part of the whole scanned image of the detection surface, and the scanned image 210 includes a plurality of first unit graphics 211.

[0047] In this embodiment, the first unit pattern 211 includes an interference defect unit pattern and a design defect unit pattern. The interference defect unit pattern is formed due to deviation in the manufacturing process, and the design defect unit pattern is formed due to design reasons.

[0048] In this embodiment, the scanned image 210 is an image of the electrical interconnection structure exposed by the inspection surface; in other embodiments, the scanned image may also be an image of the gate structure or the device structure exposed by the inspection surface.

[0049] Please refer to Figure 5 , providing a design image 220, wherein the design image 220 includes a plurality of second unit graphics 221 corresponding to the first unit graphics 211.

[0050] It should be noted that Figure 5 for Figure 4 The design image corresponding to the scanned image in .

[0051] In this embodiment, the design image 220 is used to form the semiconductor structure.

[0052] The scanned image 210 is screened according to the design image 220 to remove the interfering defective unit patterns in the first unit pattern 211. For details, please refer to Figures 6 to 8 .

[0053] In this embodiment, please continue to refer to Figure 4 and Figure 5 The method for filtering the scanned image 210 according to the design image 220 includes: obtaining a filtering value according to the design image 220 and the scanned image 210; providing a filtering condition corresponding to the filtering value; and judging whether each of the first unit graphics 211 is an interference defect unit graphics by comparing the filtering value with the filtering condition.

[0054] In this embodiment, the screening values ​​include: the overlap ratio value OR of the first unit graphic 211 and its corresponding second unit graphic 221, the characteristic size value A of the second unit graphic 221, CD and the pattern spacing value A of the second unit pattern 221 S .

[0055] In this embodiment, the screening condition includes an overlap rate threshold T OR , feature size threshold T CD and the graph spacing threshold T S .

[0056] In this embodiment, the method for determining whether each of the first unit patterns 211 is an interference defect unit pattern by comparing the screening value with the screening condition includes: when the overlap rate value OR is less than or equal to the overlap rate threshold value T OR , the characteristic size value A CD Greater than or equal to the feature size threshold T CD And the graphic spacing value A S Greater than or equal to the graphic spacing threshold T S , then it is determined that the first unit pattern 211 is an interference defect unit pattern.

[0057] In this embodiment, the overlap ratio value OR is the ratio of the overlap area A1 of the first unit pattern 211 and the corresponding second unit pattern 221 to the area A2 of the second unit pattern 221, that is, OR=A1 / A2.

[0058] In this embodiment, please refer to Figure 6 and Figure 7 , Figure 7 yes Figure 6 A part of the middle part is enlarged Figure 7, a method for obtaining an overlapping area between the first unit graphic 211 and the corresponding second unit graphic 221 includes: overlapping and aligning the design image 220 with the scanned image 210, wherein the first unit graphic 211 corresponds to the second unit graphic 221; and obtaining an overlapping area A1 between the first unit graphic 211 and the corresponding second unit graphic 221 through a Boolean operation.

[0059] In this embodiment, the characteristic size value A CD It is the size of each side length of each second unit graphic 221 in the design image. Different second unit graphics 221 may have different shapes, such as rectangles or other polygonal forms.

[0060] In this embodiment, the graphic spacing value A S is the minimum spacing value between a single second unit pattern 221 and another adjacent second unit pattern in the design image.

[0061] In this embodiment, the overlap rate threshold ranges from 60% to 90%.

[0062] Due to the defect caused by the manufacturing process deviation, the deviation between the first unit graphic 211 in the scanned image 210 corresponding to the defect and the second unit graphic 221 in the design image 220 is relatively large, and the overlapping area between the two will be correspondingly smaller; and due to the defect caused by the design, the deviation between the first unit graphic 211 in the scanned image 210 corresponding to the defect and the second unit graphic 221 in the design image 220 is relatively small, and the overlapping area between the two will be correspondingly larger; therefore, according to the difference, the overlap rate threshold is set, and by comparison, it is determined whether the overlap rate value is less than or equal to the set overlap rate threshold.

[0063] In this embodiment, the method for obtaining the feature size threshold comprises: providing a first magnification α and a minimum feature size value R specified in the design rule of the design image 220 CD ; The feature size threshold is the product of the minimum feature size value and the first magnification factor.

[0064] Since the minimum feature size value specified in the design rule is the minimum feature size in the design image, the feature size of the second unit graphic 221 in the design image cannot be less than the minimum feature size value. Therefore, after enlarging the minimum feature size value, if the feature size value of the second unit graphic 221 is greater than or equal to the value, it means that the design of the second unit graphic 221 meets the requirements, and it is necessary to further detect whether the first unit graphic 211 corresponding to the second unit graphic 221 is an interference defect unit graphic formed by the manufacturing process deviation.

[0065] In this embodiment, the first magnification factor α ranges from 2 to 5 times.

[0066] In this embodiment, the method for obtaining the pattern spacing threshold includes: providing a second magnification β and a minimum spacing dimension value R specified in the design rule of the design image 220 S ; The spacing size range is the product of the minimum spacing size value and the second magnification factor.

[0067] Since the minimum spacing dimension value specified in the design rule is the minimum spacing dimension in the design image, the spacing dimension of the second unit graphic 221 in the design image cannot be less than the minimum spacing dimension value. Therefore, after enlarging the minimum spacing dimension value, if the spacing dimension value of the second unit graphic 221 is still greater than or equal to this value, it means that the design of the second unit graphic 221 meets the requirements, and it is necessary to further detect whether the first unit graphic 211 corresponding to the second unit graphic 221 is an interference defect unit graphic formed by the manufacturing process deviation.

[0068] In this embodiment, the second magnification factor β ranges from 2 to 5 times.

[0069] Please refer to Figure 8 When the first unit pattern 211 is an interference defect unit pattern, the interference defect unit pattern is deleted from the scanned image 210.

[0070] In this embodiment, after deleting the interfering defective unit patterns in the scanned image, the remaining first unit patterns 211 still need to be inspected one by one.

[0071] Since the above method can partially remove the interfering defect unit patterns formed by the deviation of the manufacturing process in the scanned image 210, the number of first unit patterns that need to be subsequently detected and analyzed one by one can be greatly reduced, thereby shortening the detection time and improving the detection efficiency.

[0072] Accordingly, please refer to Fig. 9, an embodiment of the present invention further provides a defect detection system, comprising:

[0073] A scanning unit 300, used to obtain a scanning image of a wafer inspection surface, wherein the scanning image includes a plurality of first unit graphics;

[0074] A design image unit 310, configured to provide a design image, wherein the design image includes a plurality of second unit graphics corresponding to the first unit graphics;

[0075] The screening unit 320 screens the scanned image according to the design image to remove interfering defective unit patterns in the first unit patterns.

[0076] The following is a detailed description with reference to the accompanying drawings.

[0077] In this embodiment, please continue to refer to Fig. 9 , the screening unit 320 includes:

[0078] A measuring module 321, obtaining a screening value according to measuring the design image and the scanned image;

[0079] A screening condition module 322, providing screening conditions corresponding to the screening values;

[0080] A judgment module 323 compares the screening value with the screening condition to judge whether each of the first unit patterns is an interference defect unit pattern;

[0081] The operation module 324 deletes the interfering defective unit pattern from the scanned image when the first unit pattern is an interfering defective unit pattern.

[0082] In this embodiment, the screening values ​​include: an overlap rate value between the first unit pattern and its corresponding second unit pattern, a characteristic size value of the second unit pattern, and a pattern spacing value of the second unit pattern.

[0083] In this embodiment, the screening conditions include: an overlap rate threshold, a feature size threshold, and a pattern spacing threshold.

[0084] In this embodiment, the judgment module 323 compares the filtering value with the filtering condition to judge whether each first unit graphic is an interference defect unit graphic. The specific manifestation is: when the overlap rate value is less than or equal to the overlap rate threshold, the feature size value is greater than or equal to the feature size threshold, and the graphic spacing value is greater than or equal to the graphic spacing threshold, then the first unit graphic is judged to be an interference defect unit graphic.

[0085] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A defect detection method, characterized in that: include: Providing a wafer, wherein the wafer includes a detection surface; Scanning the detection surface to obtain a scanned image of the detection surface, wherein the scanned image includes a plurality of first unit graphics; Providing a design image, wherein the design image includes a plurality of second unit graphics corresponding to the first unit graphics; The scanned image is screened according to the design image to remove the interfering defective unit patterns formed by the deviation in the manufacturing process in the first unit pattern; wherein, The method for screening the scanned image according to the design image comprises: obtaining a screening value according to measuring the design image and the scanned image; providing a screening condition corresponding to the screening value; judging whether each of the first unit patterns is an interference defect unit pattern according to comparing the screening value with the screening condition; and deleting the interference defect unit pattern from the scanned image when the first unit pattern is an interference defect unit pattern; The screening value includes: an overlap rate value between the first unit pattern and its corresponding second unit pattern, a characteristic size value of the second unit pattern, and a pattern spacing value of the second unit pattern, wherein the overlap rate value is a ratio of an overlap area between the first unit pattern and the corresponding second unit pattern to an area of ​​the second unit pattern; The screening conditions include: overlap rate threshold, feature size threshold and pattern spacing threshold; The method for determining whether each of the first unit graphics is an interference defect unit graphics according to comparison between the screening value and the screening condition includes: when the overlap rate value is less than or equal to the overlap rate threshold, the feature size value is greater than or equal to the feature size threshold, and the graphic spacing value is greater than or equal to the graphic spacing threshold, then determining that the first unit graphics is an interference defect unit graphics.

2. The defect detection method according to claim 1, characterized in that: The method for obtaining the overlapping area between the first unit graphic and the corresponding second unit graphic includes: overlapping and aligning the design image with the scanned image, the first unit graphic corresponding to the second unit graphic; and obtaining the overlapping area between the first unit graphic and the corresponding second unit graphic through Boolean operation.

3. The defect detection method according to claim 1, characterized in that: The pattern spacing value is a minimum spacing value between a single second unit pattern and another adjacent second unit pattern in the design image.

4. The defect detection method according to claim 1, characterized in that: The overlap rate threshold ranges from 60% to 90%.

5. The defect detection method according to claim 1, characterized in that: The method for obtaining the feature size threshold comprises: providing a first magnification and a minimum feature size value specified in a design rule of the design image; the feature size threshold is the product of the minimum feature size value and the first magnification.

6. The defect detection method according to claim 5, characterized in that: The first magnification factor ranges from 2 to 5 times.

7. The defect detection method according to claim 1, characterized in that: The method for obtaining the graphic spacing threshold comprises: providing a second magnification and a minimum spacing dimension value specified in the design rule of the design image; the spacing dimension threshold is the product of the minimum spacing dimension value and the second magnification.

8. The defect detection method according to claim 7, characterized in that: The second magnification factor ranges from 2 to 5 times.

9. A defect detection system, characterized in that: include: A scanning unit, used for acquiring a scanning image of a wafer inspection surface, wherein the scanning image includes a plurality of first unit patterns; A design image unit, used for providing a design image, wherein the design image includes a plurality of second unit graphics corresponding to the first unit graphics; a screening unit, screening the scanned image according to the design image, and removing the interfering defective unit graphics formed in the first unit graphics due to the deviation in the manufacturing process; wherein the screening unit comprises: a measuring module, obtaining a screening value by measuring the design image and the scanned image; a screening condition module: used to provide a screening condition corresponding to the screening value; a judging module, judging whether each of the first unit graphics is an interfering defective unit graphics according to the comparison between the screening value and the screening condition; and an operating module, deleting the interfering defective unit graphics from the scanned image when the first unit graphics are interfering defective unit graphics; The screening conditions include: overlap rate threshold, feature size threshold and pattern spacing threshold; The screening values ​​include: an overlap rate value between the first unit graphic and its corresponding second unit graphic, a characteristic size value of the second unit graphic, and a graphic spacing value of the second unit graphic, wherein the overlap rate value is a ratio of an overlap area between the first unit graphic and the corresponding second unit graphic to an area of ​​the second unit graphic.

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