Method for detecting wafer scratches

Abstract

The invention relates to a method for detecting wafer scratches. According to the method, the detection wafer comprises the metal layer located below the detection material layer, when the detection material layer is subjected to scratch detection and the scratch degree is judged, the information of the penetrable scratch is obtained by detecting the metal corrosion defect, the detection sensitivity is high, the cost is low, and the detection efficiency is high. When the proportion of the crystal grains influenced by the penetrating scratch is less than or equal to a first set value, further detecting non-penetrating scratch; and when the proportion of the crystal grains influenced by the penetrating scratch is greater than the first set value, or the proportion of the crystal grains influenced by the penetrating scratch and the non-penetrating scratch is greater than a second set value, judging that the scratch degree of the detection material layer reaches a serious level, by means of the method, the information about whether the surface of the detection material layer is scratched or not, the type of the scratch and the scratch degree can be accurately obtained, the accuracy of scratch detection is improved, and the scratch degree can be accurately judged conveniently.

Description

Technical Field

[0001] The invention relates to the field of integrated circuit manufacturing, and in particular to a method for detecting wafer scratches. Background Art

[0002] During the integrated circuit manufacturing process, the wafer may be scratched inside the machine or on the transmission path, which will eventually affect the product yield, so scratch detection is required.

[0003] In order to detect whether the surface of the wafer is scratched, after the wafer passes through the machine or transmission path related to scratch detection, the surface of the wafer is usually directly optically scanned to check whether there is a scratch defect; however, since the scratch marks formed on the surface of the hard material are not obvious, especially some dark scratches or weak scratches, the light reflection signal at the scratch is not obvious during optical scanning, resulting in that the defect information is not easy to detect, resulting in low detection accuracy. In addition, the medium layer with high transparency (such as silicon oxide) itself does not reflect light obviously. When detecting whether there is a scratch on the surface of the medium layer with high transparency, the light reflection signal at the scratch is not obvious, and the defect information is not easy to detect, resulting in low detection accuracy. In an improved method, a photoresist layer is formed on the wafer to reduce the surface hardness, and then it passes through the machine or transmission path related to scratch detection, and then optical scanning is performed. However, experiments show that although the soft photoresist surface is easy to leave scratch marks, weak scratches are still not obvious and difficult to detect by optical scanning, and some machines or transmission paths related to scratch detection are not suitable for detection using a photoresist layer.

[0004] Since the accuracy of the above scratch detection method is relatively poor, the accuracy of judging the scratch degree based on its detection results is also poor. Summary of the invention

[0005] In order to improve the accuracy of scratch detection, especially to improve the accuracy of detecting dark scratches or weak scratches and accurately determine the degree of scratches, the present invention provides a method for detecting wafer scratches.

[0006] The method for detecting wafer scratches provided by the present invention comprises:

[0007] Acquire a test wafer, the test wafer comprising a substrate and a metal layer and a test material layer sequentially stacked on the substrate, and subject the test wafer to a simulated process treatment on a machine or a transmission path related to scratch detection;

[0008] Performing a scratch test on the detection material layer and determining the scratch degree includes:

[0009] Detecting penetrating scratches includes: infiltrating the surface of the detection material layer with a metal etching solution; detecting whether there is a metal corrosion defect, and if there is a metal corrosion defect, determining that the detection material layer has a penetrating scratch at the metal corrosion defect;

[0010] Calculating the proportion of crystal grains affected by the penetrating scratches, and further detecting non-penetrating scratches only when the proportion of crystal grains affected by the penetrating scratches is less than or equal to a first set value;

[0011] The proportion of the grains affected by the penetrating scratches and the non-penetrating scratches is calculated. When the proportion of the grains affected by the penetrating scratches is greater than the first set value, or the proportion of the grains affected by the penetrating scratches and the non-penetrating scratches is greater than the second set value, the scratch degree of the detection material layer reaches a serious level.

[0012] Optionally, the detection wafer further includes a buffer material layer between the substrate and the metal layer.

[0013] Optionally, the metal layer includes one or an alloy of Cu, Ni, Al, Fe, Ti, Ta and Cr.

[0014] Optionally, the thickness of the detection material layer is

[0015] Optionally, the detection material layer is a transparent medium layer.

[0016] Optionally, the first set value is less than or equal to the second set value.

[0017] Optionally, the first set value and the second set value are both 5%.

[0018] Optionally, detecting non-penetrating scratches includes: depositing a heterogeneous material layer on the surface of the detection material layer and performing a flattening process to remove the heterogeneous material layer above the detection material layer; detecting whether there are heterogeneous material residual defects in the area other than the penetrating scratches on the surface of the detection material layer, and if there are heterogeneous material residual defects, determining that the detection material layer has non-penetrating scratches at the heterogeneous material residual defects.

[0019] Optionally, the heterogeneous material layer is made of metal material.

[0020] Optionally, optical scanning is used to detect the metal corrosion defects and foreign material residual defects.

[0021] The method for detecting wafer scratches provided by the present invention has at least the following advantages:

[0022] First, when performing scratch detection on the detection material layer and judging the degree of scratches, first detect penetrating scratches. When the proportion of grains affected by the penetrating scratches is less than or equal to a first set value, further detect non-penetrating scratches. When the proportion of grains affected by the penetrating scratches is greater than the first set value, or the proportion of grains affected by the penetrating scratches and the non-penetrating scratches is greater than a second set value, the scratch degree of the detection material layer reaches a serious level. By using this method, it is possible to accurately obtain information on whether there are scratches on the surface of the detection material layer, the type of scratches, and the degree of scratches, thereby improving the accuracy of scratch detection and facilitating accurate judgment of the degree of scratches. In addition, the information on penetrating scratches is first obtained by detecting metal corrosion defects. Since the cost and speed of penetrating scratch detection are low, non-penetrating scratches are detected only when the proportion of grains affected by the penetrating scratches is less than or equal to a first set value, thereby facilitating shortening the detection time, reducing the detection cost, and improving the detection efficiency.

[0023] Secondly, when detecting penetrating scratches, the metal etching liquid is used to infiltrate the surface of the detection material layer from the penetrating scratches and react with the metal layer. The penetrating scratches are detected by detecting metal corrosion defects. Compared with directly detecting penetrating scratch defects, metal corrosion defects are easier to identify and have high detection sensitivity, which can improve the detection accuracy of hidden scratches or weak scratches. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of a method for detecting wafer scratches according to an embodiment of the present invention.

[0025] Figure 2 The diagram is a partial cross-sectional diagram of a detection wafer formed by a method for detecting wafer scratches according to an embodiment of the present invention.

[0026] Figure 3 It is a schematic diagram of a partial cross section of a detection wafer after being processed by a simulation process using a method for detecting wafer scratches according to an embodiment of the present invention.

[0027] Figure 4 It is a partial cross-sectional schematic diagram of a metal corrosion defect formed by a method for detecting wafer scratches according to an embodiment of the present invention.

[0028] Figure 5 It is a plan view of the test wafer with penetrating defects and non-penetrating defects after the simulation process.

[0029] Figure 6 It is a schematic diagram of a partial cross section of a detection wafer after being processed by a simulation process using a method for detecting wafer scratches according to an embodiment of the present invention.

[0030] Figure 7The diagram is a cross-sectional view of a method for detecting wafer scratches according to an embodiment of the present invention after a heterogeneous material layer is deposited on the surface of the detection wafer.

[0031] Figure 8 It is a cross-sectional schematic diagram after the surface of the heterogeneous material layer is planarized using the method for detecting wafer scratches according to an embodiment of the present invention.

[0032] Description of reference numerals:

[0033] 100 - inspection wafer; 101 - substrate; 110 - metal layer; 120 - inspection material layer; 120a - scratch defect; 111 - metal corrosion defect; 130 - foreign material layer; 131 - foreign material residual defect. DETAILED DESCRIPTION

[0034] The following is a further detailed description of the method for detecting wafer scratches of the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will become clearer. It should be understood that the drawings in the specification are all in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the structure in the figure is inverted or positioned in other different ways (such as rotated), the exemplary term "on..." may also include "under..." and other orientation relationships.

[0035] The embodiment of the present invention relates to a method for detecting wafer scratches. Figures 1 to 8 The method of detecting wafer scratches is described below.

[0036] Reference Figures 1 to 3 A method for detecting wafer scratches according to an embodiment of the present invention includes step S1: obtaining a detection wafer 100, wherein the detection wafer 100 includes a substrate 101 and a metal layer 110 and a detection material layer 120 stacked sequentially on the substrate 101, and subjecting the detection wafer 100 to a simulated process treatment on a machine or a transmission path related to scratch detection.

[0037] The substrate 101 may be a wafer without patterns (ie, a blank wafer) or a wafer with patterns formed thereon. The substrate 101 may be a silicon wafer or other substrates that can be used in semiconductor processes.

[0038] In the detection wafer 100, the metal layer 110 and the detection material layer 120 are stacked in sequence on the substrate 101. Optionally, the detection wafer 100 also includes a buffer material layer 102 between the substrate 101 and the metal layer 110. Specifically, when forming the detection wafer 100, a layer of buffer material layer 102 can be first deposited on the surface of the substrate 101, and then the metal layer 110 is formed on the surface of the buffer material layer 102, and then the detection material layer 120 is formed on the surface of the metal layer 110. The buffer material layer 102 can improve the adhesion of the metal layer 110 and relieve the stress on the surface of the substrate 101. The buffer material layer 102 may include one of silicon oxide, silicon nitride, silicon oxynitride and polysilicon, or a combination thereof. The thickness of the buffer material layer 102 is, for example, greater than or equal to

[0039] The metal layer 110 is used to detect penetrating scratches on the surface of the detection material layer 120. The metal layer 110 may include one of Cu, Ni, Al, Fe, Ti, Ta and Cr or an alloy. As an example, the metal layer 110 is formed by using a copper-aluminum alloy (AlCu). The thickness of the metal layer 110 can be set as needed, for example,

[0040] The detection material layer 120 is formed on the surface of the metal layer 110, and serves as a surface material for detecting whether the wafer 100 will be scratched. The detection material layer 120 can select a suitable material according to the machine related to the scratch detection (i.e., the suspected machine) or the transmission path (i.e., the suspected path). For example, the detection material layer 120 adopts the surface material of the wafer that has passed through the machine related to the scratch detection or the transmission path in the actual process, but is not limited to this. The detection material layer 120 can select a suitable material according to the needs of scratch detection. In order to avoid the scratch marks being unclear due to excessive hardness, a material with a hardness that can form scratch marks can be selected as the detection material layer 120. The thickness of the detection material layer 120 can be selected according to the actual test situation, for example, (i.e. greater than or equal to and less than or equal to ), further preferred

[0041] In order to confirm whether the machine or transmission path related to scratch detection has the problem of scratching the wafer and the extent of the scratch, the detection wafer 100 is subjected to simulated process treatment on the machine or transmission path related to scratch detection. Specifically, when it is found that there is a problem with the yield of the product wafer (Product Wafer) and it is related to scratches, it can be analyzed which machines or transmission paths the product wafer passes through during the process, and the machine or transmission path that may cause scratches is selected as the machine or transmission path to be inspected. As needed, multiple detection wafers 100 can be used to perform simulated process treatment on each machine or each transmission path, and then perform subsequent detection steps.

[0042] After the above simulation process, more than one penetrating scratch 120 a may be formed on the surface of the detection material layer 120 , and more than one non-penetrating scratch may also be formed. Figure 3 FIG. 1 shows a portion of the inspection wafer 100 after being processed by the simulation process. Figure 3 As shown, illustratively, in a detection wafer 100, at least a penetrating scratch 120a is formed on the surface of the detection material layer 120. The scratch of the penetrating scratch 120a forms a crack in the detection material layer 120, and the crack extends from the upper surface to the lower surface of the detection material layer 120. Since the size of the penetrating scratch 120a may be small, such as a dark scratch or a small scratch, and the difference in light reflection performance between the penetrating scratch 120a and the surrounding detection material layer 120 is not obvious, the accuracy of directly detecting the penetrating scratch 120a through optical scanning is poor.

[0043] Reference Figure 1 The method for detecting wafer scratches according to an embodiment of the present invention includes step S2: performing scratch detection on the detection material layer 120 and determining the degree of scratches.

[0044] In step S2, firstly, step S21 is performed to detect the penetrating scratches on the surface of the detection material layer 120. Step S21 specifically includes: infiltrating the surface of the detection material layer 120 with a metal etching solution; detecting whether there is a metal corrosion defect, and if there is a metal corrosion defect, determining that the detection material layer 120 has a penetrating scratch 120a at the metal corrosion defect.

[0045] When the metal etching liquid is used to infiltrate the surface of the detection material layer 120, the detection wafer 100 processed by the above-mentioned simulation process can be placed in the metal etching liquid as a whole, or only the detection material layer 120 and the metal layer 110 of the detection wafer 100 are immersed in the metal etching liquid, or the metal etching liquid can be sprayed on the surface of the detection material layer 120 processed by the above-mentioned simulation process, or other suitable methods can be used. The metal etching liquid does not react chemically with the detection material layer 120, but reacts chemically with the metal layer 110. The metal etching liquid can be HF acid solution, sulfuric acid solution or phosphoric acid solution. In order to ensure that the metal etching liquid can penetrate into the lower surface of the detection material layer 120 through the gap of the penetrating scratch 120a, so as to contact with the metal layer 110 and react chemically more fully, the detection material layer 120 is immersed in the metal etching liquid for a suitable time, for example, 1min to 10min, which can be set according to actual needs.

[0046] When no penetrating scratch is formed on the detection material layer 120 during the simulation process, the metal layer 110 will not form a metal corrosion defect after being immersed in the metal etching solution for a set period of time. However, when a penetrating scratch 120a is formed on the surface of the detection material layer 120 during the simulation process, after being immersed in the metal etching solution for a suitable period of time, the metal etching solution will penetrate into the interface between the detection material layer 120 and the metal layer 110 along the cracks generated by the penetrating scratch 120a, and react with the metal layer 110, causing the metal layer 110 in the corresponding area to undergo a chemical reaction (i.e., be corroded), and forming a metal corrosion defect 111 at the position of the penetrating scratch 120a, such as Figure 4 As shown. It can be understood that the metal corrosion defect 111 is formed by a chemical reaction in the region of the penetrating scratch 120a, and the area of ​​the metal corrosion defect 111 is larger than that of the penetrating scratch 120a caused by mechanical scratches. In addition, the light reflection performance of the metal corrosion defect 111 is significantly different from that of the material in other regions of the inspection wafer 100, and is easier to detect. That is, the metal corrosion defect 111 amplifies the defect signal of the penetrating scratch 120a at the same position, making it easier to detect, thereby improving the detection accuracy of dark scratches or weak scratches and facilitating accurate judgment of the degree of scratches.

[0047] An optical defect scanner may be used to detect whether there is a metal corrosion defect on the surface of the detection material layer 120. When performing optical defect scanning, information about the metal corrosion defect 111 may be obtained by detecting the difference in light reflection performance between the metal corrosion defect 111 and the surrounding detection material layer 120. Through defect scanning, information about whether there is a metal corrosion defect 111 on the surface of the detection wafer 100 and the position distribution of the metal corrosion defect 111 when there is a metal corrosion defect 111 may be obtained.

[0048] In an embodiment of the present invention, metal corrosion defects are used to change the manifestation of penetrating scratches, so that the information of penetrating scratches is easier to detect. Different from directly scanning the surface of the detection material layer 120 to detect scratch defects, since the light reflection performance of the metal corrosion defects and the surrounding areas where no chemical reaction occurs is quite different, it is convenient to detect metal corrosion defects. The detection material layer 120 can be made of opaque material or translucent material. As an example, the detection material layer 120 is a transparent medium layer, so that the morphology and color of the metal layer 110 can be transmitted from the transparent medium layer. When performing optical defect scanning, the metal layer 110 can be directly scanned to determine whether there are metal corrosion defects, which can further reduce the difficulty of detection and improve the detection accuracy. The detection material layer 120 may include silicon oxide or other suitable materials, such as a silicon oxide layer. Here, "transparent medium layer" refers to a medium layer with a transmittance greater than or equal to 70%.

[0049] Considering that if the degree of scratches reflected by penetrating scratches is already serious and the qualified rate of the grains cannot meet the process requirements, it is not necessary to spend time and material testing to see if the simulated process treatment still causes non-penetrating scratches on the surface of the detection material layer 120. Figure 1 As shown, in this embodiment, after completing the detection of penetrating scratches, step S22 is executed to calculate the proportion of grains affected by the penetrating scratches 120a, and only when the proportion of grains affected by the penetrating scratches 120a is less than or equal to the first set value, further detection of non-penetrating scratches is performed. By further detecting non-penetrating scratches, it is convenient to know whether the detection wafer 100 is affected by non-penetrating scratches, so as to obtain accurate information on the scratch condition of the detection material layer 120.

[0050] Figure 5 FIG. 1 shows a plan view of the test wafer 100 having penetrating scratches 120a and non-penetrating scratches 120b after the above-mentioned simulation process. Figure 5 As shown, a plurality of dies are arranged on the inspection wafer 100 (each dies is as shown in FIG. Figure 5 As shown in the small grid in the figure, the actual number of grains on the inspection wafer is much larger than Figure 5 The number of grains shown in the figure), the penetrating scratch 120a and the non-penetrating scratch 120b can pass through at least one grain area, thereby affecting the grains passed through. Figure 5 After obtaining the information of the metal corrosion defect 111, it is possible to obtain whether a penetrating scratch 120a is formed on the surface of the detection material layer 120 and the position distribution information of the penetrating scratch 120a when it is formed.

[0051] The proportion of grains affected by the penetrating scratches 120a is the ratio of the number of grains affected by all penetrating scratches 120a (which may be multiple penetrating scratches 120a) detected in step S21 to the total number of grains on the detection wafer 100. The first set value can be set according to actual needs. When the proportion of grains affected by the penetrating scratches 120a exceeds the first set value, the scratch degree of the detection material layer 120 reaches a serious level. For example, the grain pass rate of the detection wafer 100 reaching the serious level is too low and needs to be scrapped. As an example, the first set value is 5%, that is, when the proportion of grains affected by the penetrating scratches 120a is less than or equal to 5%, it is further detected whether non-penetrating scratches 120a are formed on the surface of the detection material layer 120 and the distribution of non-penetrating scratches 120a when formed. In one embodiment, if the penetrating scratch 120a is not detected in step S21, the proportion of grains affected by the penetrating scratch 120a is 0, which is less than the first set value, and non-penetrating scratches 120b can be further detected.

[0052] Figure 6 FIG. 1 shows a partial cross section of the inspection wafer 100. Referring to FIG. Figure 6 For example, a non-penetrating scratch 120b is formed on the surface of the detection material layer 120 in the detection wafer 100, and the non-penetrating scratch 120b causes a groove to be formed on the surface of the detection material layer 120. As an example, the non-penetrating scratch 120b and the above-mentioned penetrating scratch 120a are located in different areas of the detection wafer 100.

[0053] In this embodiment, detecting the non-penetrating scratch 120b includes, for example, the following process:

[0054] First, if Figure 7 As shown, a heterogeneous material layer 130 is deposited on the surface of the detection material layer 120. The heterogeneous material layer 130 and the detection material layer 120 are made of different materials so that the light reflection properties of the two are different, which is convenient for detecting residual defects of the heterogeneous material;

[0055] Then, if Figure 8 As shown, a planarization process (such as a CMP process) is performed to remove the heterogeneous material layer 130 above the detection material layer 120. The thickness of the heterogeneous material layer 130 removed by the planarization process is substantially equal to the thickness of the heterogeneous material layer 130 deposited on the surface of the detection material layer 100.

[0056] Afterwards, the detection material layer 120 is detected to see whether the area other than the penetrating scratch 120a on the surface has a foreign material residual defect 131. If there is a foreign material residual defect 131, it is determined that the detection material layer 120 has a non-penetrating scratch 120b at the foreign material residual defect 131.

[0057] The heterogeneous material layer 130 is preferably made of a material with good groove filling performance and a light reflection performance that is significantly different from that of the detection material layer 120. As an example, the heterogeneous material layer 130 is made of a metal material, such as tungsten or copper. The thickness of the heterogeneous material layer 130 deposited on the surface of the detection material layer 120 is, for example, The heterogeneous material layer 130 fills the groove formed by the non-penetrating scratch 120b on the surface of the detection material layer 120, and also covers the top surface of the detection material layer 120. When the CMP process is performed to remove the heterogeneous material layer 130 above the detection material layer 120, the top surface of the detection material layer 120 can be used as a grinding stop layer. After the CMP process is completed, the top surface of the detection material layer 120 is exposed, but the heterogeneous material layer 130 filled in the groove of the non-penetrating scratch 120b is retained, forming a heterogeneous material residual defect 131.

[0058] An optical defect scanner can be used to perform defect scanning on the detection material layer 120. During defect scanning, information about the heterogeneous material residual defect 131 is obtained by detecting the difference in light reflection performance between the heterogeneous material residual defect 131 and the surrounding detection material layer 120. Through defect scanning, information about whether the surface of the detection wafer 100 has a heterogeneous material residual defect 131 and the position distribution of the heterogeneous material residual defect 131 when it is formed can be obtained. Since the heterogeneous material residual defect 131 corresponds to the formation of the non-penetrating scratch 120b, through the defect scanning, information about whether the detection wafer 100 forms a non-penetrating scratch 120b after the above-mentioned simulation process and the distribution information of the non-penetrating scratch 120b when it is formed can be obtained.

[0059] In this embodiment, the same test wafer 100 is used to detect whether penetrating scratches 120a and non-penetrating scratches 120b are formed on the surface of the test material layer 120, but it is not limited thereto. In another embodiment, multiple test wafers 100 with the same simulation process can be manufactured, and different test wafers 100 are selected from them to detect penetrating scratches 120a and non-penetrating scratches 120b. Since the penetrating scratch 120a is detected first, when the non-penetrating scratch 120b is detected by the above-mentioned heterogeneous material residual defect 131, the heterogeneous material residual defect formed at the penetrating scratch 120a can be excluded based on the information of the penetrating scratch 120a obtained in advance, so as to accurately obtain the information of the non-penetrating scratch 120b.

[0060] The above method for detecting the non-penetrating scratch 120b is only an example, and other methods may be used to obtain information about the non-penetrating scratch 120b. For example, in one embodiment, when detecting the non-penetrating scratch 120b, a heterogeneous material layer 130 is first deposited on the surface of the detection material layer 120, and then the heterogeneous material layer 130 above the detection material layer 120 is removed by maskless etching, and residual defects of the heterogeneous material are detected. In another embodiment, when detecting non-penetrating scratches 120b, the heterogeneous material layer 130 is not deposited, but dry etching is first performed to reduce the thickness of the detection material layer 120, so that the bottom of the groove at the non-penetrating scratch 120b is penetrated to expose the metal layer 110. In the area without scratches, the metal layer 110 is not exposed. Then, the surface of the detection material layer 120 is infiltrated with a metal etching solution, and whether the area of ​​the detection material layer 120 other than the penetrating scratch position has a metal corrosion defect. If so, it is determined that the detection material layer 120 has a non-penetrating scratch at the metal corrosion defect other than the penetrating scratch.

[0061] like Figure 1 As shown, after completing the detection of the above-mentioned penetrating scratches 120a and non-penetrating scratches 120b, step S23 is then executed to calculate the proportion of grains affected by the penetrating scratches 120a and non-penetrating scratches 120b. When the proportion of grains affected by the penetrating scratches 120a is greater than the first set value, or the proportion of grains affected by the penetrating scratches 120a and non-penetrating scratches 120b is greater than the second set value, the scratch degree of the detection material layer 120 reaches a serious level.

[0062] The percentage of grains affected by penetrating scratches 120a has been obtained in step S22. After obtaining the information of non-penetrating scratches 120b, the number of grains affected by all non-penetrating scratches 120b can be calculated, and the ratio thereof to the total number of grains on the detection wafer 100 can be calculated to obtain the percentage of grains affected by non-penetrating scratches 120b. The percentage of grains affected by penetrating scratches 120a and the percentage of grains affected by non-penetrating scratches 120b can be added together to obtain the percentage of grains affected by penetrating scratches 120a and non-penetrating scratches 120b. However, it is not limited to this. In one embodiment, the number of grains affected by all penetrating scratches 120a and the number of grains affected by all non-penetrating scratches 120b can be added together first, and then divided by the total number of grains on the detection wafer 100, to obtain the percentage of grains affected by penetrating scratches 120a and non-penetrating scratches 120b.

[0063] In this embodiment, in order to accurately obtain information on the degree of scratches, it is determined whether the proportion of grains affected by penetrating scratches 120a and non-penetrating scratches 120b is greater than a second set value. If it is greater than the second set value, it is determined that the degree of scratches on the detection material layer 120 has reached a serious level. The second set value can be set according to actual needs, for example, the first set value is less than or equal to the second set value. The second set value and the first set value are both equal to 5%, for example.

[0064] In the method for detecting wafer scratches described in the above embodiment, the detection wafer 100 includes a metal layer 110 located below the detection material layer 120. After being placed in the machine or transmission path to be inspected for simulation process processing, the detection material layer 120 may be scratched, for example, forming dark scratches or small scratches. In order to make these scratches easier to detect, the penetrating scratch 120a is first used to make the metal layer 110 react with the metal etching solution, and the information of the penetrating scratch 120a is obtained by detecting the metal corrosion defect 111. The detection cost is low and the speed is fast. It also improves the accuracy of scratch detection, especially the detection accuracy of dark scratches or weak scratches. Moreover, since the light reflection performance of the metal corrosion defect 111 and the surrounding area without metal corrosion is quite different, the transparency of the detection material layer 120 does not affect the detection of the metal corrosion defect 111. The detection material layer 120 can select a transparent medium material or other suitable materials, both of which can achieve higher detection accuracy.

[0065] In addition, in the above-mentioned method for detecting wafer scratches, the proportion of grains affected by the penetrating scratch 120a is compared with the first set value based on the information of the penetrating scratch 120a. Only when the proportion of grains affected by the penetrating scratch 120a is less than or equal to the first set value, the non-penetrating scratch 120b is further detected, so that the detection is more comprehensive, and the detection accuracy of hidden scratches or weak scratches is further improved. It is also convenient to shorten the detection time, reduce the cost of the entire detection process, and improve the detection efficiency. In addition, by judging whether the proportion of grains affected by the penetrating scratch 120a is greater than the first set value and judging whether the proportion of grains affected by the penetrating scratch 120a and the non-penetrating scratch 120b is greater than the second set value, it is convenient to accurately judge the degree of scratches.

[0066] The above description is only a description of the preferred embodiment of the present invention, and is not any limitation on the scope of rights of the present invention. Any technical personnel in this field can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for detecting wafer scratches, characterized in that: include: Acquire a test wafer, the test wafer comprising a substrate and a metal layer and a test material layer sequentially stacked on the substrate, and subject the test wafer to a simulated process treatment on a machine or a transmission path related to scratch detection; Performing a scratch test on the detection material layer and determining the scratch degree includes: Detecting penetrating scratches includes: infiltrating the surface of the detection material layer with a metal etching solution; detecting whether there is a metal corrosion defect, and if there is a metal corrosion defect, determining that the detection material layer has a penetrating scratch at the metal corrosion defect; Calculating the proportion of crystal grains affected by the penetrating scratches, and further detecting non-penetrating scratches only when the proportion of crystal grains affected by the penetrating scratches is less than or equal to a first set value; The proportion of the grains affected by the penetrating scratches and the non-penetrating scratches is calculated. When the proportion of the grains affected by the penetrating scratches is greater than the first set value, or the proportion of the grains affected by the penetrating scratches and the non-penetrating scratches is greater than the second set value, the scratch degree of the detection material layer reaches a serious level.

2. The method for detecting wafer scratches according to claim 1, characterized in that: The detection wafer further includes a buffer material layer between the substrate and the metal layer.

3. The method for detecting wafer scratches according to claim 1, characterized in that: The metal layer includes one of Cu, Ni, Al, Fe, Ti, Ta and Cr, or an alloy thereof.

4. The method for detecting wafer scratches according to claim 1, characterized in that: The thickness of the detection material layer is 5. The method for detecting wafer scratches according to claim 1, characterized in that: The detection material layer is a transparent medium layer.

6. The method for detecting wafer scratches according to claim 1, characterized in that: The first setting value is less than or equal to the second setting value.

7. The method for detecting wafer scratches according to claim 6, characterized in that: The first set value and the second set value are both 5%.

8. The method for detecting wafer scratches according to claim 1, characterized in that: Detecting non-penetrating scratches includes: depositing a heterogeneous material layer on the surface of the detection material layer and performing a flattening process to remove the heterogeneous material layer above the detection material layer; detecting whether the area other than the penetrating scratch on the surface of the detection material layer has a heterogeneous material residual defect, and if so, determining that the detection material layer has a non-penetrating scratch at the heterogeneous material residual defect.

9. The method for detecting wafer scratches according to claim 8, characterized in that: The heterogeneous material layer is made of metal material.

10. The method for detecting wafer scratches according to claim 8, characterized in that: Optical scanning is used to detect the metal corrosion defects and foreign material residual defects.

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