Silicon wafer judging method and device

Abstract

The application provides a silicon wafer judging method and device, and belongs to the technical field of semiconductor manufacturing. The silicon wafer judging method comprises the following steps: acquiring particle distribution information of a surface of a silicon wafer to be detected, wherein the particle distribution information comprises the number and coordinates of particles on the surface of the silicon wafer; dividing the silicon wafer into a plurality of sub-regions; judging whether the number of particles contained in the plurality of sub-regions satisfies a preset rule according to the particle distribution information; and if yes, judging that the particles on the surface of the silicon wafer have a preset pattern. The technical scheme of the application can identify a silicon wafer with a single aggregated special particle pattern on the surface.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a method and apparatus for determining silicon wafers. Background Technology

[0002] In semiconductor manufacturing, the cleanliness of the silicon wafer surface is one of the most important factors affecting the reliability of semiconductor devices. During the silicon wafer shipping process, a particle inspection process is carried out to detect the particles on the surface of the silicon wafer. Silicon wafers with more than a specified number of particles are judged as unqualified products. In addition, in some cases, it is also necessary to determine whether the particle distribution on the silicon wafer surface has a single aggregated special particle pattern. Currently, this can only be determined manually, which is inefficient and prone to missed detections. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a silicon wafer identification method and apparatus that can identify silicon wafers with a single aggregated special particle pattern on their surface.

[0004] To achieve the above objectives, the technical solution adopted in the embodiments of the present invention is as follows:

[0005] A method for determining silicon wafers, comprising:

[0006] Obtain particle distribution information on the surface of the silicon wafer to be tested, wherein the particle distribution information includes the number and coordinates of particles on the silicon wafer surface;

[0007] The silicon wafer is divided into multiple sub-regions;

[0008] Based on the particle distribution information, it is determined whether the number of particles contained in the multiple sub-regions meets the preset rules. If it does, it is determined that the particles on the silicon wafer surface have a preset pattern.

[0009] In some embodiments, the sub-region is a square region.

[0010] In some embodiments, determining whether the number of particles contained in the plurality of sub-regions meets a preset rule based on the particle distribution information includes:

[0011] The number of particles contained in each sub-region is determined based on the particle distribution information;

[0012] Based on the number of particles contained in each sub-region, the sub-regions are sorted in descending order of the number of particles;

[0013] The preset rules include:

[0014] The number of particles in the first sub-region exceeds a preset first threshold.

[0015] The sum of the number of particles in the first to fourth sub-regions as a percentage of the total number of particles exceeds a preset second threshold.

[0016] The difference in the number of particles between the first sub-region and the fifth sub-region exceeds the preset third threshold.

[0017] In some embodiments, the second threshold is 93-97%.

[0018] In some embodiments, obtaining the particle distribution information on the surface of the silicon wafer to be tested includes:

[0019] A metal thin film is formed on the surface of the silicon wafer to be tested, and a metal thin film shell is formed to surround the particles on the surface of the silicon wafer to be tested.

[0020] The silicon wafer to be tested is tested, and in the test, the particle distribution information on the surface of the silicon wafer to be tested is obtained based on the scattered light signal formed by the scattering of measurement light by the particles on the silicon wafer to be tested.

[0021] After the test is completed, the metal film on the silicon wafer to be tested is removed.

[0022] In some embodiments, the particles include silica particles and nitrogen dioxide particles.

[0023] This invention also provides a silicon wafer determination device, comprising:

[0024] The acquisition module is used to acquire particle distribution information on the surface of the silicon wafer to be detected, wherein the particle distribution information includes the number and coordinates of particles on the silicon wafer surface;

[0025] A partitioning module is used to divide the silicon wafer into multiple sub-regions;

[0026] The determination module is used to determine whether the number of particles contained in the multiple sub-regions meets the preset rules based on the particle distribution information. If the rules are met, the particles on the silicon wafer surface are determined to have a preset pattern.

[0027] In some embodiments, the determination module is specifically used to determine the number of particles contained in each sub-region based on the particle distribution information; and to sort the multiple sub-regions according to the number of particles contained in each sub-region in descending order of particle count.

[0028] The preset rules include:

[0029] The number of particles in the first sub-region exceeds a preset first threshold.

[0030] The sum of the number of particles in the first to fourth sub-regions as a percentage of the total number of particles exceeds a preset second threshold.

[0031] The difference in the number of particles between the first sub-region and the fifth sub-region exceeds the preset third threshold.

[0032] In some embodiments, the acquisition module is specifically used to form a metal thin film on the surface of the silicon wafer to be tested, and simultaneously form a metal thin film shell surrounding the particles on the surface of the silicon wafer to be tested; to test the silicon wafer to be tested, wherein, based on the scattered light signal formed by the scattering of measurement light by the particles on the silicon wafer to be tested, the particle distribution information on the surface of the silicon wafer to be tested is obtained; and after the test is completed, the metal thin film on the silicon wafer to be tested is removed.

[0033] This invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps in the silicon wafer determination method described above.

[0034] The beneficial effects of this invention are:

[0035] In this embodiment, the number of particles contained in multiple sub-regions of the silicon wafer is determined based on the particle distribution information on the silicon wafer surface. If the number of particles meets the preset rules, it is determined that the particles on the silicon wafer surface have a preset pattern. This embodiment can automatically determine whether the particles on the silicon wafer surface have a preset pattern based on the obtained particle distribution information on the silicon wafer surface. By setting the preset rules, silicon wafers with a single aggregated special particle pattern on the surface can be identified. The detection efficiency is high and there will be no missed detection. Attached Figure Description

[0036] Figure 1 A schematic flowchart illustrating the silicon wafer determination method according to an embodiment of the present invention;

[0037] Figures 2-4 This is a schematic diagram illustrating how a silicon wafer is divided into multiple sub-regions according to an embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram showing the structure of the silicon wafer determination device according to an embodiment of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0040] This invention provides a silicon wafer identification method and apparatus that can identify silicon wafers with a special pattern of surface particle distribution.

[0041] This invention provides a method for determining silicon wafers, such as... Figure 1 As shown, it includes:

[0042] Step 101: Obtain particle distribution information on the surface of the silicon wafer to be tested, wherein the particle distribution information includes the number and coordinates of particles on the silicon wafer surface;

[0043] In semiconductor manufacturing, foreign matter particles can form on the surface of silicon wafers. Optical detection methods can be used to obtain information on the particle distribution on the silicon wafer surface. Optical detection methods have advantages such as not damaging the cleanliness of the silicon wafer surface and being able to detect in real time.

[0044] Specifically, a metal thin film can be formed on the surface of the silicon wafer to be tested, and a metal thin film shell surrounding the particles on the surface of the silicon wafer to be tested can be formed simultaneously; the silicon wafer to be tested is tested, and in the test, the particle distribution information on the surface of the silicon wafer to be tested is obtained based on the scattered light signal formed by the scattering of measurement light by the particles on the silicon wafer to be tested; after the test is completed, the metal thin film on the silicon wafer to be tested is removed.

[0045] After metal coating, the surface of the silicon wafer under test is covered by a thin metal film. Simultaneously, if there are particles on the silicon wafer, these particles on the surface will also be covered by the metal film, forming particles with a metal film shell. These particles are typically organic materials, insulating materials, etc., with silicon dioxide and nitrogen dioxide particles being the most common. Silica particles produce the weakest detection signal and are the most difficult to detect. By forming a metal film shell on the particle surface, the scattering of measurement light by the particles is greatly enhanced, forming a stronger scattered light signal, thus increasing detection accuracy. Even if the particles are small, they can still be detected by the detector due to the strong scattered light signal, thus improving the detection limit of particle detection. The metal film shell on the particle surface has high reflectivity, which increases the scattered signal. Furthermore, when measurement light is projected onto particles including the metal film shell, surface plasmon resonance occurs, greatly enhancing the scattering of measurement light and thus strengthening the scattered signal.

[0046] In this embodiment, the metal thin film can be made of gold (Au), silver (Ag), platinum (Pt), titanium (Ti), or aluminum (Al), but the invention is not limited to these. Preferably, the metal thin film material is Ti or Al, because Ti and Al are commonly used metal materials in the mid-to-back-end of semiconductor manufacturing processes, and the processes for Ti and Al deposition, etching, and cleaning are very mature in semiconductor production. In this embodiment, the metal thin film is cleaned by a chemical solution. When selecting a chemical solution, it is necessary to choose a cleaning solution that can react with the metal material without damaging the silicon wafer under test.

[0047] In this embodiment, after using the above-mentioned optical detection method, the number of particles on the silicon wafer surface, as well as the coordinates and particle size of the particles, can be obtained. This information can be stored in a database, and when it is necessary to identify the silicon wafer, this information can be read from the database.

[0048] Step 102: Divide the silicon wafer into multiple sub-regions;

[0049] like Figure 2 As shown, the silicon wafer 01 can be divided into multiple square sub-regions 02 according to the coordinate system where the particle coordinates are located. Of course, in this embodiment, the sub-regions are not limited to square regions; they can also be other shapes, such as parallelograms, sectors, irregular shapes, etc. Generally, the size of the special pattern formed by aggregated particles does not exceed 2cm, so the silicon wafer can be divided into multiple 2cm*2cm sub-regions. Figure 2 As shown, it can be seen that in the central region of silicon wafer 01, sub-region 02 is square, and in the edge region of silicon wafer 01, sub-region 02 is part of a square.

[0050] Step 103: Determine whether the number of particles contained in the multiple sub-regions meets the preset rules based on the particle distribution information. If it does, determine that the particles on the silicon wafer surface have a preset pattern.

[0051] In this embodiment, by setting preset rules, silicon wafers with a single aggregated special particle pattern on their surface can be identified. Specifically, after dividing the silicon wafer 01 into multiple square sub-regions 02, the number of particles contained in each sub-region can be determined based on the coordinates and quantity of the particles; based on the number of particles contained in each sub-region, the multiple sub-regions are sorted from most to least numerous, with the first sub-region containing the most particles; after sorting, it can be determined whether the number of particles contained in the multiple sub-regions satisfies the preset rules, which may include:

[0052] The number of particles in the first sub-region exceeds a preset first threshold.

[0053] The sum of the number of particles in the first to fourth sub-regions as a percentage of the total number of particles exceeds a preset second threshold.

[0054] The difference in the number of particles between the first sub-region and the fifth sub-region exceeds the preset third threshold.

[0055] The first, second, and third thresholds can be set as needed. For example, in some embodiments, the first threshold can be 150-200, specifically, the first threshold can be 150, 160, 170, 180, 190, or 200; the second threshold can be 93-97%, specifically, the second threshold can be 93%, 94%, 95%, 96%, or 97%; and the third threshold can be 100-150, specifically, the third threshold can be 100, 110, 120, 130, 140, or 150.

[0056] It can be seen that when the preset rules are met, most of the particles on the silicon wafer are clustered in the first to fourth sub-regions. At this time, the silicon wafer is determined to be a silicon wafer with a single clustered special particle pattern.

[0057] In a specific example, such as Figure 3 As shown, the particles 03 on the surface of silicon wafer 01 are distributed in multiple (more than 5) sub-regions 02, and the number of particles in multiple sub-regions 02 is relatively close. Most of the particles on the silicon wafer are not clustered in the first to fourth sub-regions. Therefore, the silicon wafer is determined to be a silicon wafer without a single clustered special particle pattern.

[0058] In another specific example, such as Figure 4 As shown, the particles 03 on the surface of silicon wafer 01 are distributed in multiple (more than 5) sub-regions 02, and are concentrated in four of them (the part within the dashed box). That is, most of the particles on silicon wafer 01 are clustered in the first to fourth sub-regions. Therefore, the silicon wafer is determined to be a silicon wafer with a single clustered special particle pattern. In this embodiment, when a preset pattern change needs to be detected, the preset rules can be adjusted according to the characteristics of the preset pattern, so that the technical solution of this embodiment can be applied to the identification of various special patterns.

[0059] In this embodiment, the number of particles contained in multiple sub-regions of the silicon wafer is determined based on the particle distribution information on the silicon wafer surface. If the number of particles meets the preset rules, it is determined that the particles on the silicon wafer surface have a preset pattern. This embodiment can automatically determine whether the particles on the silicon wafer surface have a preset pattern based on the obtained particle distribution information on the silicon wafer surface. By setting the preset rules, silicon wafers with a single aggregated special particle pattern on the surface can be identified. The detection efficiency is high and there will be no missed detection.

[0060] This invention also provides a silicon wafer determination device, such as... Figure 5 As shown, it includes:

[0061] The acquisition module 21 is used to acquire particle distribution information on the surface of the silicon wafer to be detected, wherein the particle distribution information includes the number and coordinates of particles on the silicon wafer surface;

[0062] In semiconductor manufacturing, foreign matter particles can form on the surface of silicon wafers. Optical detection methods can be used to obtain information on the particle distribution on the silicon wafer surface. Optical detection methods have advantages such as not damaging the cleanliness of the silicon wafer surface and being able to detect in real time.

[0063] Specifically, the acquisition module 21 can form a metal thin film on the surface of the silicon wafer to be tested, and at the same time form a metal thin film shell surrounding the particles on the surface of the silicon wafer to be tested; the silicon wafer to be tested is tested, and in the test, the particle distribution information on the surface of the silicon wafer to be tested is obtained based on the scattered light signal formed by the scattering of measurement light by the particles on the silicon wafer to be tested; after the test is completed, the metal thin film on the silicon wafer to be tested is removed.

[0064] After metal coating, the surface of the silicon wafer under test is covered by a thin metal film. Simultaneously, if there are particles on the silicon wafer, these particles on the surface will also be covered by the metal film, forming particles with a metal film shell. These particles are typically organic materials, insulating materials, etc., with silicon dioxide and nitrogen dioxide particles being the most common. Silica particles produce the weakest detection signal and are the most difficult to detect. By forming a metal film shell on the particle surface, the scattering of measurement light by the particles is greatly enhanced, forming a stronger scattered light signal, thus increasing detection accuracy. Even if the particles are small, they can still be detected by the detector due to the strong scattered light signal, thus improving the detection limit of particle detection. The metal film shell on the particle surface has high reflectivity, which increases the scattered signal. Furthermore, when measurement light is projected onto particles including the metal film shell, surface plasmon resonance occurs, greatly enhancing the scattering of measurement light and thus strengthening the scattered signal.

[0065] In this embodiment, the metal thin film can be made of gold (Au), silver (Ag), platinum (Pt), titanium (Ti), or aluminum (Al), but the invention is not limited to these. Preferably, the metal thin film material is Ti or Al, because Ti and Al are commonly used metal materials in the mid-to-back-end of semiconductor manufacturing processes, and the processes for Ti and Al deposition, etching, and cleaning are very mature in semiconductor production. In this embodiment, the metal thin film is cleaned by a chemical solution. When selecting a chemical solution, it is necessary to choose a cleaning solution that can react with the metal material without damaging the silicon wafer under test.

[0066] In this embodiment, after using the above-mentioned optical detection method, the number of particles on the silicon wafer surface, as well as the coordinates and particle size of the particles, can be obtained. This information can be stored in a database, and when it is necessary to identify the silicon wafer, this information can be read from the database.

[0067] The partitioning module 22 is used to divide the silicon wafer into multiple sub-regions;

[0068] like Figure 2 As shown, the partitioning module 22 can divide the silicon wafer 01 into multiple square sub-regions 02 according to the coordinate system where the particle coordinates are located. Of course, in this embodiment, the sub-regions are not limited to square regions; they can also be other shapes, such as parallelograms, sectors, irregular shapes, etc. Generally, the size of the special pattern formed by aggregated particles does not exceed 2cm, so the silicon wafer can be divided into multiple 2cm*2cm sub-regions. Figure 2 As shown, it can be seen that in the central region of silicon wafer 01, sub-region 02 is square, and in the edge region of silicon wafer 01, sub-region 02 is part of a square.

[0069] The determination module 23 is used to determine whether the number of particles contained in the multiple sub-regions meets the preset rules based on the particle distribution information. If the rules are met, the particles on the silicon wafer surface are determined to have a preset pattern.

[0070] Specifically, after dividing the silicon wafer 01 into multiple square sub-regions 02, the determination module 23 can determine the number of particles contained in each sub-region based on the number and coordinates of the particles; based on the number of particles contained in each sub-region, the multiple sub-regions are sorted in descending order of particle count; after sorting, it can be determined whether the number of particles contained in the multiple sub-regions meets a preset rule, which may include:

[0071] The number of particles in the first sub-region exceeds a preset first threshold.

[0072] The sum of the number of particles in the first to fourth sub-regions as a percentage of the total number of particles exceeds a preset second threshold.

[0073] The difference in the number of particles between the first sub-region and the fifth sub-region exceeds the preset third threshold.

[0074] The first, second, and third thresholds can be set as needed. For example, in some embodiments, the first threshold can be 150-200, specifically, the first threshold can be 150, 160, 170, 180, 190, or 200; the second threshold can be 93-97%, specifically, the second threshold can be 93%, 94%, 95%, 96%, or 97%; and the third threshold can be 100-150, specifically, the third threshold can be 100, 110, 120, 130, 140, or 150.

[0075] It can be seen that when the preset rules are met, most of the particles on the silicon wafer are clustered in the first to fourth sub-regions. At this time, the silicon wafer is determined to be a silicon wafer with a single clustered special particle pattern.

[0076] In a specific example, such as Figure 3 As shown, the particles 03 on the surface of silicon wafer 01 are distributed in multiple (more than 5) sub-regions 02, and the number of particles in multiple sub-regions 02 is relatively close. Most of the particles on the silicon wafer are not clustered in the first to fourth sub-regions. Therefore, the silicon wafer is determined to be a silicon wafer without a single clustered special particle pattern.

[0077] In another specific example, such as Figure 4 As shown, the particles 03 on the surface of silicon wafer 01 are distributed in multiple (more than 5) sub-regions 02, and are concentrated in four of them (the part within the dashed box). That is, most of the particles on silicon wafer 01 are gathered in the first to fourth sub-regions. Therefore, the silicon wafer is determined to be a silicon wafer with a single aggregated special particle pattern.

[0078] In this embodiment, when a preset pattern change needs to be detected, the preset rules can be adjusted according to the characteristics of the preset pattern, so that the technical solution of this embodiment can be applied to the recognition of a variety of special patterns.

[0079] In this embodiment, the number of particles contained in multiple sub-regions of the silicon wafer is determined based on the particle distribution information on the silicon wafer surface. If the number of particles meets the preset rules, it is determined that the particles on the silicon wafer surface have a preset pattern. This embodiment can automatically determine whether the particles on the silicon wafer surface have a preset pattern based on the obtained particle distribution information on the silicon wafer surface. By setting the preset rules, silicon wafers with a single aggregated special particle pattern on the surface can be identified. The detection efficiency is high and there will be no missed detection.

[0080] This invention also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps in the silicon wafer determination method described above.

[0081] Computer-readable media, including both permanent and non-permanent, removable and non-removable media, can store information using any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage, or any other non-transferable medium that can be used to store information accessible to the computer-readable terminal device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0082] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining silicon wafers, characterized in that, include: Obtain particle distribution information on the surface of the silicon wafer to be tested, wherein the particle distribution information includes the number and coordinates of particles on the silicon wafer surface; The silicon wafer is divided into multiple sub-regions; Based on the particle distribution information, it is determined whether the number of particles contained in the multiple sub-regions meets the preset rules. If it does, it is determined that the particles on the silicon wafer surface have a preset pattern. The step of determining whether the number of particles contained in the multiple sub-regions meets the preset rules based on the particle distribution information includes: The number of particles contained in each sub-region is determined based on the particle distribution information; Based on the number of particles contained in each sub-region, the sub-regions are sorted in descending order of the number of particles; The preset rules include: The number of particles in the first sub-region exceeds a preset first threshold. The sum of the number of particles in the first to fourth sub-regions as a percentage of the total number of particles exceeds a preset second threshold. The difference in the number of particles between the first sub-region and the fifth sub-region exceeds the preset third threshold.

2. The silicon wafer determination method according to claim 1, characterized in that, The sub-region is a square region.

3. The silicon wafer determination method according to claim 2, characterized in that, The second threshold is 93-97%.

4. The silicon wafer determination method according to claim 1, characterized in that, The process of obtaining particle distribution information on the surface of the silicon wafer to be tested includes: A metal thin film is formed on the surface of the silicon wafer to be tested, and a metal thin film shell is formed to surround the particles on the surface of the silicon wafer to be tested. The silicon wafer to be tested is tested, and in the test, the particle distribution information on the surface of the silicon wafer to be tested is obtained based on the scattered light signal formed by the scattering of measurement light by the particles on the silicon wafer to be tested. After the test is completed, the metal film on the silicon wafer to be tested is removed.

5. The silicon wafer determination method according to claim 1, characterized in that, The particles include silica particles and nitrogen dioxide particles.

6. A silicon wafer judging device, characterized in that, include: The acquisition module is used to acquire particle distribution information on the surface of the silicon wafer to be detected, wherein the particle distribution information includes the number and coordinates of particles on the silicon wafer surface; A partitioning module is used to divide the silicon wafer into multiple sub-regions; The determination module is used to determine whether the number of particles contained in the multiple sub-regions meets the preset rules based on the particle distribution information. If the rules are met, the particles on the silicon wafer surface are determined to have a preset pattern. The determination module is specifically used to determine the number of particles contained in each sub-region based on the particle distribution information; Based on the number of particles contained in each sub-region, the sub-regions are sorted in descending order of the number of particles; The preset rules include: The number of particles in the first sub-region exceeds a preset first threshold. The sum of the number of particles in the first to fourth sub-regions as a percentage of the total number of particles exceeds a preset second threshold. The difference in the number of particles between the first sub-region and the fifth sub-region exceeds the preset third threshold.

7. The silicon wafer determining device according to claim 6, characterized in that, The acquisition module is specifically used to form a metal thin film on the surface of the silicon wafer to be tested, and simultaneously form a metal thin film shell surrounding the particles on the surface of the silicon wafer to be tested; to test the silicon wafer to be tested, and in the test, to obtain particle distribution information on the surface of the silicon wafer to be tested based on the scattered light signal formed by the scattering of measurement light by the particles on the silicon wafer to be tested; and to remove the metal thin film on the silicon wafer to be tested after the test is completed.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the silicon wafer determination method as described in any one of claims 1-5.

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