Semiconductor wafer evaluation method and manufacturing method, and semiconductor wafer manufacturing process management method
The laser surface inspection device determines LPD before and after the cleaning process, and determines particles, adhered particles and PID based on the detection results, which solves the problem of difficult to distinguish between grinding surface defects/foreign objects in the prior art, and improves the wafer quality and cleaning efficiency .
Patent Information
- Application Number
- CN201980086184.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2018-12-27
- Filing Date
- 2019-11-11
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2039-11-11
AI Technical Summary
It is difficult for the prior art to accurately determine the defects/foreign species of the abrasive surface of the semiconductor wafer, especially when the cleaning force is reduced in the cleaning process, it makes it difficult to distinguish between particle residues and PID residues, affecting the quality of the wafer.
The laser surface inspection device was used to measure Light Point Defect (LPD) separately before and after the cleaning process, and the particles, adhered particles and PID were determined according to the detection size difference, and the defect/foreign species were determined through Table A's discrimination benchmark, and then the cleaning solution was adjusted and the Reprocessing strategy.
Accurate judgment of defects/foreign species of semiconductor wafer grinding surfaces is achieved, the reduction of cleaning force in the cleaning process is sensed, and the cleaning liquid is replaced in time to reduce the need for re-grinding and improve the quality of the wafer.
Smart Images
Figure FDA0005136495400000011 
Figure FDA0005136495400000012 
Figure FDA0005136495400000021
Abstract
Description
[0001] Cross-references of related applications
[0002] This application claims the benefit of priority based on Japanese Patent Application No. 2018-245448, filed on December 27, 2018, the entire contents of which are expressly incorporated herein by reference. Technical Field
[0003] The present invention relates to an evaluation method and a manufacturing method of a semiconductor wafer and a manufacturing process management method of a semiconductor wafer, and in particular, to an evaluation method and a manufacturing method of a semiconductor wafer having a polished surface and a manufacturing process management method of a semiconductor wafer having a polished surface. Background Art
[0004] As an apparatus for evaluating a semiconductor wafer, a laser surface inspection apparatus is widely used (for example, refer to Japanese Patent Application Laid-Open No. 2016-212009 (the entire contents of which are expressly incorporated herein by reference)). Summary of the invention
[0005] Evaluation using a laser surface inspection device allows light to enter the surface of a semiconductor wafer to be evaluated and detects radiated light (scattered light and reflected light) from the surface to evaluate the presence and size of defects and foreign matter in the semiconductor wafer.
[0006] Among semiconductor wafers, a polished wafer is a semiconductor wafer manufactured through various processes including a grinding process, and its surface (outermost surface) is a ground surface. Here, the ground surface refers to a surface that has been mirror-polished (also called mirror-finished). Various defects / foreign matter may exist on the ground surface. The causes of these defects / foreign matter are different, so the countermeasures for reducing them (reprocessing, process management, etc.) are also different. Therefore, if the type of defects / foreign matter present in the ground surface can be identified, a polished wafer with fewer defects or foreign matter can be provided by implementing countermeasures corresponding to the type.
[0007] One embodiment of the present invention provides a new evaluation method capable of identifying the type of defects and foreign matter present on the ground surface of a polished wafer.
[0008] Defects / foreign matter present in the grinding surface of a polished wafer are generally roughly divided into particles (Particle) and PID (Polished Induced Defect). Particles are foreign matter attached to the grinding surface, and PID is a convex defect introduced during the grinding process. Since particles are foreign matter attached to the surface of the grinding surface, it was previously considered that they can be easily removed by the cleaning process usually performed on semiconductor wafers. In contrast, since PID is a defect, it will not be removed by such a cleaning process. Therefore, in order to distinguish between particles and PID, it is considered that defects / foreign matter that are measured as LPD (Light Point Defect) before a certain cleaning process but not measured after the cleaning process will be judged as particles, and defects / foreign matter that are measured as LPD before and after the cleaning process will be judged as PID. However, the inventors of the present invention have newly discovered in repeated discussions that, for example, when the same cleaning solution is repeatedly used and the cleaning solution deteriorates, thereby reducing the cleaning power of a certain cleaning process, the number of particles remaining after the cleaning process increases. In this regard, the inventors of the present invention classified the particles removed by a certain cleaning process (the cleaning process to be discussed) as "normal particles" and classified the particles remaining after a certain cleaning process as "firmly-adherent particles". As long as it is possible to distinguish between normal particles and firmly-adherent particles, it is possible to sense the reduction in the cleaning power of a certain cleaning process by using, for example, the number of firmly-adherent particles as an indicator, for example, it is possible to grasp the period when the cleaning liquid used in the cleaning process should be replaced. However, the defects / foreign matter measured as LPD after a certain cleaning process is not limited to firmly-adherent particles, but may also be PID. Therefore, in order to sense the reduction in the cleaning power of a cleaning process as described above, it is also required to be able to distinguish between firmly-adherent particles and PID.
[0009] In view of the above, the present inventors further repeated intensive studies to distinguish PID, normal particles, and adhered particles, and as a result, completed the following evaluation method.
[0010] That is, one embodiment of the present invention relates to a method for evaluating a semiconductor wafer (hereinafter, also simply described as “evaluation method”), which is a method for evaluating a semiconductor wafer having a polished surface.
[0011] A cleaning step comprising cleaning the semiconductor wafer using one or more cleaning solutions,
[0012] Include:
[0013] The LPD of the polished surface is measured using a laser surface inspection device before and after the cleaning step.
[0014] Based on the measurement results obtained by the above measurement, according to the following judgment criteria:
[0015] Table 1
[0016] Table A
[0017] Measurement results Type of defect or foreign matter LPD where the detected dimension X before the cleaning process and the detected dimension Y after the cleaning process satisfy the relationship X<Y PID LPD detected before the above cleaning process but not detected after the above cleaning process Usually granules LPD where the detected dimension X before the cleaning process and the detected dimension Y after the cleaning process satisfy the relationship X ≥ Y Adhesion particles
[0018] , to determine the type of defect or foreign matter measured as LPD.
[0019] "Normal particles" are foreign matter that can be removed by cleaning in a certain cleaning process (cleaning process of the subject of discussion) as described above. In the above evaluation method, LPD detected before the above cleaning process but not detected after the above cleaning process is identified as "normal particles".
[0020] On the other hand, the defects / foreign matters that were not removed by the above-mentioned cleaning process were "adherent particles" and "PID". Since they were not removed by the above-mentioned cleaning process, they were both measured as LPD.
[0021] However, according to the research of the present inventors, it is clear that the detected size of "adherent particles" before and after the cleaning process remains unchanged, or the detected size becomes smaller after the cleaning process. The reason is presumed to be that the adherent particles may become smaller due to partial dissolution in the cleaning process.
[0022] On the other hand, according to the discussion of the present inventors, it is clear that the detection size of "PID" after the cleaning process is larger than that before the cleaning process, which is different from the adhesion particles. The reason for this is presumably that the PID acts like a mask when etching the polished surface in the cleaning process and selectively remains.
[0023] According to the discrimination criteria shown in the above Table A, which are determined based on the phenomenon newly clarified by the above inventors' discussion, "PID", "normal particles" and "adherent particles" can be discriminated. As a result, for example, it is possible to sense the reduction in the cleaning power of the cleaning process. Thus, it is possible to judge the necessity of replacing the cleaning liquid or to judge whether the semiconductor wafer after the cleaning process should be re-cleaned. Furthermore, for example, by using the number of PIDs measured as LPD as an indicator, it is also possible to judge the necessity of re-grinding or the necessity of process management of the grinding process.
[0024] In one embodiment, the cleaning step may be a cleaning step performed using one or more cleaning solutions containing an inorganic acid.
[0025] In one embodiment, the cleaning step may include HF cleaning and SC-1 cleaning.
[0026] One embodiment of the present invention relates to a method for manufacturing a semiconductor wafer having a polished surface (hereinafter, also simply described as “manufacturing method”), comprising:
[0027] Mirror polishing is performed on a semiconductor wafer to form a polished surface;
[0028] A cleaning step of cleaning the semiconductor wafer having the polished surface formed thereon using one or more cleaning liquids;
[0029] Before and after the cleaning step, the LPD of the polished surface is measured using a laser surface inspection device; and
[0030] Based on the measurement results obtained by the above measurement, the type of defect or foreign matter measured as LPD is determined according to the determination criteria shown in the above Table A.
[0031] The method further includes submitting the semiconductor wafers determined as qualified products based on the above determination results to a preparation process for shipment as products.
[0032] In one embodiment, the manufacturing method may further include: submitting the semiconductor wafer determined as a defective product as a result of the determination to a reprocessing step; and submitting the semiconductor wafer after the reprocessing step to a preparation step for shipment as a product.
[0033] In one embodiment, the reprocessing step may be at least one step selected from the group consisting of a polishing step and a cleaning step.
[0034] One embodiment of the present invention relates to a method for managing a manufacturing process of a semiconductor wafer (hereinafter, also simply referred to as a “management method”).
[0035] The manufacturing processes of the managed objects include:
[0036] performing a polishing step of mirror-polishing the semiconductor wafer to form a polished surface; and
[0037] A cleaning step of cleaning the semiconductor wafer having the polished surface formed thereon using one or more cleaning liquids is performed.
[0038] Include:
[0039] Before and after the cleaning step, the LPD of the polished surface is measured using a laser surface inspection device; and
[0040] Based on the measurement results obtained by the above measurement, the type of defect or foreign matter measured as LPD is determined according to the determination criteria shown in the above Table A.
[0041] The method further includes determining the necessity of one or both of the management of the polishing step and the management of the cleaning step based on a result of the determination.
[0042] In one embodiment, the management of the cleaning step may include replacing one or more cleaning solutions used in the cleaning step.
[0043] According to one embodiment of the present invention, it is possible to identify the types of various defects and foreign matter present on the polished surface of a polished wafer. DETAILED DESCRIPTION
[0044] [Evaluation method for semiconductor wafers]
[0045] One embodiment of the present invention relates to an evaluation method for a semiconductor wafer, which is an evaluation method for a semiconductor wafer having a polished surface, comprising a cleaning step of cleaning the semiconductor wafer using one or more cleaning liquids, and measuring the LPD of the polished surface using a laser surface inspection device before and after the cleaning step, and based on the measurement results obtained by the above measurement, the type of defect or foreign matter measured as LPD is judged according to the judgment criteria shown in the above Table A.
[0046] Hereinafter, the above-mentioned evaluation method will be described in more detail.
[0047] <Evaluation target semiconductor wafer>
[0048] The semiconductor wafer evaluated by the above evaluation method is a semiconductor wafer having a polished surface (a surface subjected to mirror polishing), that is, a polished wafer. The above semiconductor wafer can be various semiconductor wafers such as a silicon wafer. Its diameter can be, for example, 200 mm, 300 mm, or 450 mm, but is not particularly limited.
[0049] <Washing process>
[0050] In the above evaluation method, LPD measurement using a laser surface inspection device is performed on the semiconductor wafer to be evaluated before and after the cleaning process. The cleaning process performed between the two LPD measurements is a cleaning process in which the semiconductor wafer is cleaned using one or more cleaning liquids. In such a cleaning process, as the cleaning liquid, one or more cleaning liquids commonly used for cleaning semiconductor wafers, such as a cleaning liquid containing one or more inorganic acids, can be used. Examples of the cleaning liquid containing inorganic acids include a cleaning liquid containing hydrogen fluoride (HF), H 2 O 2, hydrochloric acid, sulfuric acid, nitric acid and other inorganic acids in aqueous solution. The inorganic acid concentration of the cleaning solution can be the concentration commonly used in the cleaning of semiconductor wafers and is not particularly limited. In one embodiment, the cleaning process performed between two LPD measurements can include HF cleaning and SC-1 cleaning. "HF cleaning" refers to a cleaning treatment using hydrofluoric acid (an aqueous solution of hydrogen fluoride), and the concentration of hydrogen fluoride in the hydrofluoric acid can be, for example, 0.05 to 5% by mass. "SC-1 cleaning (Standard Cleaning-1: Standard Cleaning-1)" refers to a cleaning treatment using a mixture of ammonia water, hydrogen peroxide water and H 2 The ammonia concentration of the ammonia water can be, for example, 25 to 35% by mass, and the H 2 O 2 The concentration can be, for example, 25 to 35% by mass. 2 The mixing ratio of O, for example, can be 0.1 to 1 volume of ammonia water, and 5 to 15 volume of water, based on the volume of hydrogen peroxide water (1). In addition, cleaning can be performed by immersing the wafer in each cleaning solution. The immersion time of the wafer in each cleaning solution can be, for example, 0.5 to 10 minutes, and can be determined according to the required cleaning level without particular limitation.
[0051] <LPD measurement>
[0052] The LPD measurement is performed using a laser surface inspection device. As the laser surface inspection device, a laser surface inspection device of a structure known as a device for inspecting the surface of a semiconductor wafer, which is also called a light scattering type surface inspection device, a surface inspection machine, etc., can be used without any restrictions. The laser surface inspection device usually uses laser light to scan the surface of the semiconductor wafer of the evaluation object, and uses the radiated light (scattered light or reflected light) to detect the defects / abnormalities on the wafer surface as LPD. In addition, by measuring the radiated light from the LPD, the size or position of the defect / abnormality can be identified. As the laser light, ultraviolet light, visible light, etc. can be used, and the wavelength is not particularly limited. Ultraviolet light refers to light in a wavelength range of less than 400nm, and visible light refers to light in a wavelength range of 400 to 600nm. The analysis unit of the laser surface inspection device usually converts the size of the LPD detected by the laser surface inspection device into the size of the defect / abnormality based on the correlation between the size of the standard particle and the size of the LPD caused by the standard particle. The analysis unit that performs such a conversion usually includes a PC (Personal Computer: personal computer) loaded with conversion software, and the structure of the analysis unit is well known. The detection size recorded in Table A can be the size of the LPD or the size of the defect / abnormality converted as described above. Specific examples of commercially available laser surface inspection devices include Surfscan series SP1, SP2, SP3, SP5, etc. manufactured by KLA TENCOR. However, these devices are illustrative only, and other laser surface inspection devices can also be used.
[0053] <Defect / Abnormality Identification>
[0054] In the above evaluation method, based on the results of LPD measurement performed before and after the above cleaning step, the type of defect / foreign matter measured as LPD is determined according to the determination criteria shown in the following Table A. The details of the present inventors' discussion on this point are as described above.
[0055] Table 2
[0056] Table A
[0057] Measurement results Type of defect or foreign matter LPD where the detected dimension X before the cleaning process and the detected dimension Y after the cleaning process satisfy the relationship X<Y PID LPD detected before the cleaning process but not detected after the cleaning process Usually granules LPD where the detected dimension X before the cleaning process and the detected dimension Y after the cleaning process satisfy the relationship X ≥ Y Adhesion particles
[0058] According to the above-described evaluation method, "PID", "normal particles" and "adherent particles" can be distinguished.
[0059] [Method for manufacturing semiconductor wafer]
[0060] One embodiment of the present invention relates to a method for manufacturing a semiconductor wafer having a ground surface, i.e., a polished wafer, which includes: performing mirror polishing on a semiconductor wafer to form a ground surface; performing a cleaning process of cleaning the semiconductor wafer having the ground surface using one or more cleaning liquids; measuring the LPD of the ground surface using a laser surface inspection device before and after the cleaning process; and based on the measurement results obtained by the above-mentioned measurement, judging the type of defect or foreign matter measured as LPD according to the judgment criteria shown in the above-mentioned Table A, and also includes: submitting the semiconductor wafer judged to be a qualified product based on the above-mentioned judgment result to a preparation process for shipping out as a product.
[0061] The polished wafer can be manufactured by a manufacturing process including the following processes: cutting (slicing) of a wafer from a semiconductor ingot such as a silicon single crystal ingot, chamfering, rough grinding (e.g., polishing), etching, mirror polishing (polishing), and a cleaning process performed between or after the above-mentioned processing steps. In the above-mentioned manufacturing method, LPD measurement is performed on the ground surface (the surface subjected to mirror polishing) of the polished wafer before and after the cleaning process. For such a cleaning process, reference can be made to the previous records about the cleaning process in the above-mentioned evaluation method. In addition, in one embodiment, a cleaning process may be further included before the cleaning process performed before the LPD measurement. For the cleaning process that can be further included, reference can also be made to the previous records about the cleaning process in the above-mentioned evaluation method.
[0062] In the above manufacturing method, based on the measurement results of the LPD measurement respectively performed before and after the cleaning process, the type of defects or foreign matter measured as LPD is judged according to the judgment criteria shown in the above Table A. Then, the semiconductor wafer judged as a qualified product based on the judgment results obtained in this way is submitted to the preparation process for shipping out as a product. The judgment criteria for judging qualified products are not particularly limited, and can be arbitrarily set according to the cleaning level required for the cleaning process performed between the above two LPD measurements and the PID reduction level required for the product semiconductor wafer. By performing qualified product judgment in this way, semiconductor wafers with fewer particles or PID can be stably supplied to the market. In addition, in the above manufacturing method, in a series of manufacturing processes performed before the polished wafer is shipped out, qualified product judgment can be performed by performing LPD measurement that can be implemented as a non-destructive inspection. As preparations for shipping out as product semiconductor wafers, for example, subsequent processes such as further cleaning processes, packaging, etc. can be cited.
[0063] On the other hand, semiconductor wafers judged as defective products based on the above-mentioned discrimination results can be submitted to a reprocessing process. For example, for semiconductor wafers judged as defective products because the number of LPDs judged as PIDs exceeds the level allowed for qualified products, a grinding process can be implemented to reduce PID as a reprocessing process. In addition, for semiconductor wafers judged as defective products because the number of LPDs judged as adhered particles exceeds the level allowed for qualified products, a cleaning process can be implemented to reduce adhered particles as a reprocessing process. In this way, semiconductor wafers judged as defective products are submitted to a preparation process for shipping as products after the reprocessing process, thereby making it possible to stably supply semiconductor wafers with fewer particles or PIDs to the market. With regard to the grinding process and cleaning process implemented as a reprocessing process, known techniques related to grinding and cleaning of semiconductor wafers can be applied.
[0064] [Manufacturing process management method for semiconductor wafers]
[0065] One embodiment of the present invention relates to a method for managing the manufacturing process of a semiconductor wafer, which is a method for managing the manufacturing process of a semiconductor wafer, wherein the manufacturing process of the management object includes: a grinding process of performing a grinding treatment on the semiconductor wafer to form a grinding surface; and a cleaning process of using one or more cleaning liquids to clean the semiconductor wafer having the above-mentioned grinding surface, including: using a laser surface inspection device to measure the LPD of the above-mentioned grinding surface before and after the above-mentioned cleaning process; and based on the measurement results obtained by the above-mentioned measurement, according to the judgment criteria shown in the above-mentioned Table A, the type of defects or foreign matter measured as LPD is judged, and also includes: judging the necessity of one or both of the management of the above-mentioned grinding process and the management of the above-mentioned cleaning process based on the above-mentioned judgment results.
[0066] The manufacturing process of the above-mentioned management object can be a manufacturing process that is usually performed as a manufacturing process of a polished wafer. Then, in the above-mentioned management method, the polished wafer manufactured in the manufacturing process of the management object is submitted to LPD measurement before and after the above-mentioned cleaning process. Regarding such a cleaning process, reference can be made to the previous record of the cleaning process in the above-mentioned evaluation method. In addition, in one embodiment, a cleaning process can be further included before the cleaning process performed before the LPD measurement. Regarding the cleaning process that can be further included, reference can also be made to the previous record of the cleaning process in the above-mentioned evaluation method.
[0067] Regarding the cleaning process, reference can be made to the previous description of the cleaning process. In addition, in one embodiment, a further cleaning process may be included before the cleaning process performed before the LPD measurement. Regarding the cleaning process that may be further included, reference can also be made to the previous description of the cleaning process.
[0068] The management of the polishing process includes the change of polishing conditions such as replacement of polishing liquid, change of polishing liquid composition, replacement of polishing pad, change of polishing pad type, change of polishing device operating conditions, etc. The management of the cleaning process includes the change of cleaning liquid, change of cleaning liquid composition, change of cleaning time, change of cleaning times, change of cleaning device operating conditions, etc.
[0069] In the above management method, based on the measurement results of LPD measurements performed before and after the cleaning process, the type of defects or foreign matter measured as LPD is judged according to the judgment criteria shown in the above Table A. Then, based on the judgment results obtained in this way, the necessity of one or both of the management of the above grinding process and the management of the above cleaning process is judged. For example, if the number of LPDs judged as PIDs exceeds the level allowed for qualified products, it is judged that the management of the grinding process is necessary. By implementing the management of the grinding process, polished wafers with less PID can be manufactured after the management of the grinding process. On the other hand, if the number of LPDs judged as adhered particles exceeds the level allowed for qualified products, it is judged that the management of the cleaning process is necessary. By implementing the management of the cleaning process such as replacement of the cleaning liquid, polished wafers with less particles can be manufactured after the management of the cleaning process. Example
[0070] Hereinafter, the present invention will be further described based on examples. However, the present invention is not limited to the embodiments shown in the examples.
[0071] In the following, Surfscan series SP5 manufactured by KLA TENCOR is used as a laser surface inspection device. In Surfscan series SP5 manufactured by KLA TENCOR, there is one incident system, and as an incident system, there is a UV light source that makes the incident light obliquely incident on the surface of the wafer to be evaluated. As a light receiving system, there are three light receiving systems, namely, DNO (Dark-Field Narrow Oblique) channel, DW1O (Dark-Field Wide1 Oblique) channel and DW2O (Dark-Field Wide2 Oblique) channel. The DW1O channel and the DW2O channel are light receiving systems at a low angle relative to the DNO channel. The following LPD measurement is performed using the DW1O channel as the light receiving system, but the DNO channel and the DW2O channel can also be used.
[0072] Next, the incident light is scanned over the entire range of the polished surface of the polished wafer to be evaluated, defects / abnormalities are detected as LPD, and based on the size of the LPD, a size transformation is performed in the analysis unit of the above-mentioned laser surface inspection device to calculate the size of the defect / abnormality (detection size).
[0073] The HF cleaning described below is cleaning with hydrofluoric acid having a hydrogen fluoride concentration of 0.05 to 5 mass %, and the SC-1 cleaning described below is cleaning with ammonia water having an ammonia concentration of 25 to 35 mass %. 2 O 2 Hydrogen peroxide solution with a concentration of 25 to 35% by mass: H 2 Cleaning was performed with SC1 solution of O=0.5:1:10 (volume ratio). Each cleaning was performed by immersing the entire wafer to be cleaned in each cleaning solution for 0.5 to 10 minutes.
[0074] A silicon single crystal wafer (a polished wafer with a diameter of 300 mm) having a polished surface formed by mirror polishing was prepared, and the polished wafer was subjected to a first cleaning step (HF cleaning and SC-1 cleaning were performed in sequence).
[0075] The first LPD measurement was performed on the polished surface of the polished wafer after the first cleaning step using a laser surface inspection device.
[0076] The polished wafer after the first LPD measurement was subjected to a second cleaning step (HF cleaning and SC-1 cleaning were performed in sequence).
[0077] The second LPD measurement was performed on the polished surface of the polished wafer after the second cleaning step using a laser surface inspection device.
[0078] The polished surface of the polished wafer after the second LPD measurement is observed using a SEM (Scanning Electron Microscope), and defects / abnormalities on the polished surface are classified into PID and particles. PID and particles can be distinguished by morphological observation using an SEM.
[0079] Based on the LPD coordinate data, the LPD detected in the first LPD measurement but not in the second LPD measurement, and the LPD detected in both the first LPD measurement and the second LPD measurement are determined respectively, and according to the discrimination criteria shown in Table A, various LPDs are discriminated as any of PIDs, adhered particles and ordinary particles.
[0080] In addition, as a determination of defects / foreign matter based on SEM observation, the determination of PID, adhered particles, and normal particles is performed according to the following determination criteria based on the LPD coordinate data and the positional identification and type determination results of the defects / foreign matter using SEM observation. Defects / foreign matter that are detected as LPD in the first LPD measurement but are not detected in the above-mentioned SEM observation are classified as "normal particles." Defects / foreign matter that are detected as LPD in both the first LPD measurement and the second LPD measurement and are determined to be particles through the above-mentioned SEM observation are classified as "adhered particles." Defects / foreign matter that are detected as LPD in both the first LPD measurement and the second LPD measurement and are determined to be PID through the above-mentioned SEM observation are classified as "PID."
[0081] When comparing the results obtained by LPD measurement with the results obtained by SEM observation, it was confirmed that 86.5% of the defects / abnormalities classified as PID by SEM observation were also classified as PID by LPD measurement, 96.4% of the defects / abnormalities classified as adhered particles by SEM observation were also classified as adhered particles by LPD measurement, and 99.3% of the defects / abnormalities classified as normal particles by SEM observation were also classified as normal particles by LPD measurement.
[0082] From the above results, it can be confirmed that the evaluation method using the discrimination criteria shown in Table A can discriminate PID, adhered particles, and normal particles with high accuracy. It takes a long time to observe the morphology of defects / abnormalities existing in the polished surface by SEM to discriminate their types. In contrast, discrimination based on LPD measurement using a laser surface inspection device can be performed without such a long time.
[0083] The present invention is useful in the field of manufacturing polished wafers.
Claims
1. A method for evaluating a semiconductor wafer, which is a method for evaluating a semiconductor wafer, wherein: The semiconductor wafer to be evaluated is a semiconductor wafer having a polished surface. A cleaning step comprising cleaning the semiconductor wafer using one or more cleaning solutions, Include: The LPD of the polished surface is measured using a laser surface inspection device before and after the cleaning process. Based on the measurement results obtained by the above measurement, according to the following criteria: Table A ， To identify the type of defect or foreign matter detected by LPD, The cleaning process includes HF cleaning and SC-1 cleaning, wherein the HF cleaning refers to a cleaning process performed using an aqueous solution of hydrogen fluoride, wherein the concentration of hydrogen fluoride is 0.05 to 5% by mass, and the SC-1 cleaning refers to a cleaning process performed using an SC1 solution mixed with ammonia water, hydrogen peroxide water, and H2O, wherein the ammonia concentration of the ammonia water is 25 to 35% by mass, and the H2O2 concentration of the hydrogen peroxide water is 25 to 35% by mass. PID is a convex defect introduced during the grinding process.
2. A method for manufacturing a semiconductor wafer having a polished surface, wherein: Include: Mirror polishing is performed on a semiconductor wafer to form a polished surface; A cleaning step of cleaning the semiconductor wafer having the polished surface formed thereon using one or more cleaning liquids; Before and after the cleaning step, the LPD of the polished surface is measured using a laser surface inspection device; and Based on the measurement results obtained by the above measurement, according to the following criteria: Table A ， To identify the type of defect or foreign matter detected by LPD, The method further comprises: submitting the semiconductor wafers judged as qualified products based on the results of the judgment to a preparation process for shipment as products, The cleaning process includes HF cleaning and SC-1 cleaning, wherein the HF cleaning refers to a cleaning process performed using an aqueous solution of hydrogen fluoride, wherein the concentration of hydrogen fluoride is 0.05 to 5% by mass, and the SC-1 cleaning refers to a cleaning process performed using an SC1 solution mixed with ammonia water, hydrogen peroxide water, and H2O, wherein the ammonia concentration of the ammonia water is 25 to 35% by mass, and the H2O2 concentration of the hydrogen peroxide water is 25 to 35% by mass. PID is a convex defect introduced during the grinding process.
3. The method for manufacturing a semiconductor wafer according to claim 2, wherein: Also includes: Submitting the semiconductor wafer determined as a defective product as a result of the determination to a reprocessing step; and The semiconductor wafer after the reprocessing step is submitted to a preparation step for shipment as a product.
4. The method for manufacturing a semiconductor wafer according to claim 3, wherein: The reprocessing step is at least one step selected from the group consisting of a grinding step and a cleaning step.
5. A method for managing the manufacturing process of a semiconductor wafer, which is a method for managing the manufacturing process of a semiconductor wafer, wherein: The manufacturing processes of the managed objects include: performing a polishing step of mirror-polishing the semiconductor wafer to form a polished surface; and performing a cleaning step of cleaning the semiconductor wafer having the polished surface formed thereon using one or more cleaning liquids, Include: Before and after the cleaning step, the LPD of the polished surface is measured using a laser surface inspection device; and Based on the measurement results obtained by the above measurement, according to the following criteria: Table A ， To identify the type of defect or foreign matter detected by LPD, The method further includes: determining the necessity of one or both of the management of the polishing process and the management of the cleaning process based on the result of the determination, The cleaning process includes HF cleaning and SC-1 cleaning, wherein the HF cleaning refers to a cleaning process performed using an aqueous solution of hydrogen fluoride, wherein the concentration of hydrogen fluoride is 0.05 to 5% by mass, and the SC-1 cleaning refers to a cleaning process performed using an SC1 solution mixed with ammonia water, hydrogen peroxide water, and H2O, wherein the ammonia concentration of the ammonia water is 25 to 35% by mass, and the H2O2 concentration of the hydrogen peroxide water is 25 to 35% by mass. PID is a convex defect introduced during the grinding process.
6. The method for managing the manufacturing process of a semiconductor wafer according to claim 5, wherein: The management of the cleaning process includes replacing one or more cleaning solutions used in the cleaning process.