CN112204712A - Method for cleaning silicon wafer - Google Patents
Method for cleaning silicon wafer Download PDFInfo
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- CN112204712A CN112204712A CN201980036009.9A CN201980036009A CN112204712A CN 112204712 A CN112204712 A CN 112204712A CN 201980036009 A CN201980036009 A CN 201980036009A CN 112204712 A CN112204712 A CN 112204712A
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- 238000004140 cleaning Methods 0.000 title claims abstract description 175
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 118
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 118
- 239000010703 silicon Substances 0.000 title claims abstract description 118
- 238000000034 method Methods 0.000 title claims abstract description 36
- 239000000126 substance Substances 0.000 claims abstract description 83
- 239000007788 liquid Substances 0.000 claims abstract description 31
- 230000001590 oxidative effect Effects 0.000 claims abstract description 21
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 32
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 239000002245 particle Substances 0.000 abstract description 13
- 235000012431 wafers Nutrition 0.000 description 110
- 238000011156 evaluation Methods 0.000 description 40
- 230000000052 comparative effect Effects 0.000 description 24
- 230000007547 defect Effects 0.000 description 13
- 239000000243 solution Substances 0.000 description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 8
- 239000002184 metal Substances 0.000 description 7
- 239000013078 crystal Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 239000010419 fine particle Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 2
- 238000007517 polishing process Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 230000005856 abnormality Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02041—Cleaning
- H01L21/02043—Cleaning before device manufacture, i.e. Begin-Of-Line process
- H01L21/02052—Wet cleaning only
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/02—Elements
- C30B29/06—Silicon
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
- H01L21/02227—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process
- H01L21/0223—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate
- H01L21/02233—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer
- H01L21/02236—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor
- H01L21/02238—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a process other than a deposition process formation by oxidation, e.g. oxidation of the substrate of the semiconductor substrate or a semiconductor layer group IV semiconductor silicon in uncombined form, i.e. pure silicon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
Abstract
The present invention provides a method for cleaning a silicon wafer, which comprises cleaning a silicon wafer with an oxidizing cleaning liquid after SC1 cleaning, characterized in that a chemical oxide film formed on the surface of the silicon wafer by SC1 cleaning is cleaned with the oxidizing cleaning liquid, and the chemical oxide film has a thickness of 1.0nm or more. Thus, a method for cleaning a silicon wafer is provided, which has good particle quality and can form a stable chemical oxide film.
Description
Technical Field
The invention relates to a method for cleaning a silicon wafer.
Background
In the manufacturing process of a single crystal silicon wafer, the main surface of the single crystal silicon wafer is finished in a polishing process. There is further a cleaning process for removing a polishing agent and metal impurities attached to the surface of the silicon wafer in the polishing process. In this cleaning step, a cleaning method called RCA cleaning is used. This RCA Cleaning method is a Cleaning method in which SC1(Standard Cleaning 1), SC2(Standard Cleaning 2), and DHF (Diluted Hydrofluoric Acid) Cleaning are combined according to the purpose. The SC1 cleaning is a cleaning method in which ammonia water and hydrogen peroxide are mixed at an arbitrary ratio, adhered particles are detached (lift off) by etching the surface of a silicon wafer with an alkaline cleaning solution, and the particles are removed while preventing the re-adhesion to the silicon wafer by electrostatic repulsion between the silicon wafer and the particles. The SC2 cleaning is a cleaning method for removing metal impurities on the surface of a silicon wafer by dissolving the metal impurities in a cleaning solution prepared by mixing hydrochloric acid and hydrogen peroxide at an arbitrary ratio. DHF cleaning is a cleaning method for removing a chemical oxide film on the surface of a silicon wafer by dilute hydrofluoric acid. Further, there are cases where removal of organic substances adhering to the surface of the silicon wafer or formation of a chemical oxide film on the surface of the silicon wafer after DHF cleaning is performed by cleaning with ozone water having a strong oxidizing property. These cleaning methods are combined according to the purpose to clean the silicon wafer (patent documents 1 to 3).
Documents of the prior art
Patent document
Patent document 1: japanese laid-open patent publication No. 2002-329691
Patent document 2: japanese laid-open patent publication No. 9-017765
Patent document 3: japanese laid-open patent publication No. 9-260328
Patent document 4: japanese laid-open patent application No. 2006-208314
Disclosure of Invention
Technical problem to be solved by the invention
As an important silicon wafer quality after cleaning, there is a fine particle quality. The degree of difficulty of adhesion of the fine particles to the silicon wafer varies depending on the kind of the cleaning liquid. Since the cleaning liquid used for SC1 cleaning is alkaline, it has a characteristic that particles are less likely to adhere electrostatically. On the other hand, the cleaning liquid used for SC2 cleaning is acidic and therefore has a characteristic of being easily electrostatically attached. Further, since the chemical oxide film on the surface of the silicon wafer is peeled off in the DHF cleaning, the exposed surface is exposed while the surface is acidic, and particles are very likely to adhere to the surface. Therefore, in order to obtain a good quality of fine particles, the surface of the silicon wafer is generally covered with a chemical oxide film after cleaning. Namely, a combination of SC1 cleaning and SC2 cleaning was formed.
On the other hand, there are various methods for evaluating the quality of a silicon wafer after cleaning, but among them, there is DSOD (Direct Surface Oxide Defect) evaluation as a method for evaluating the Surface quality. The quality evaluated by this DSOD evaluation is affected by surface defects of silicon wafers, crystal defects, metal contamination, the quality of a chemical oxide film formed in a cleaning process, and the like. Therefore, when the exact cause is not clear, the DSOD quality may be deteriorated or may vary. Therefore, in order to improve DSOD quality, it is necessary to improve surface defects and crystal defects and stabilize the quality of the chemical oxide film formed in the cleaning process.
In the RCA cleaning, the chemical oxide film formed in the SC1 cleaning step is very thin. The chemical oxide film thickness after SC1 cleaning was measured by XPS (X-ray photoelectron spectroscopy), which was about 0.7 nm. Even if the cleaning time or the cleaning liquid temperature was changed during the actual time of manufacturing silicon wafers, the thickness of the chemical oxide film formed in the SC1 cleaning did not change, and it was found that the thickness of the chemical oxide film could not be controlled under the SC1 cleaning conditions. With such a very thin chemical oxide film, it is difficult to stabilize the quality of the chemical oxide film, hindering the improvement of the DSOD quality.
Therefore, the improvement of the wafer quality has been a technical problem in the formation of a stable chemical oxide film and a good particle quality when cleaning a silicon wafer.
Means for solving the problems
In order to achieve the above object, the present invention provides a method for cleaning a silicon wafer, which comprises subjecting the silicon wafer to SC1 cleaning and then cleaning the silicon wafer with an oxidizing cleaning liquid, wherein a chemical oxide film formed on the surface of the silicon wafer by the SC1 cleaning is cleaned with the oxidizing cleaning liquid, thereby further growing the chemical oxide film to a thickness of 1.0nm or more.
In such a method of cleaning a silicon wafer, the chemical oxide film formed on the surface of the silicon wafer can be formed to be thicker than conventional methods by 1.0nm or more, and the surface quality of the silicon wafer can be improved.
In this case, it is preferable to use ozone water and/or hydrogen peroxide as the cleaning liquid having oxidizing property.
The method of cleaning a silicon wafer of the present invention is particularly effective in such a case.
Further, it is preferable that the SC2 cleaning is performed after the SC1 cleaning and before the cleaning with the oxidizing cleaning liquid.
In such a method of cleaning a silicon wafer, the metal impurities on the surface of the silicon wafer can be dissolved and removed, thereby further improving the surface quality of the silicon wafer.
It is preferable that the silicon wafer subjected to SC1 cleaning is a silicon wafer not subjected to DHF cleaning.
In such a method of cleaning a silicon wafer, since the chemical oxide film is not removed in advance, a sufficient chemical oxide film thickness can be obtained, and the surface quality of the silicon wafer can be more reliably improved.
Effects of the invention
In the method for cleaning a silicon wafer according to the present invention, the chemical oxide film formed on the surface of the silicon wafer can be formed to be 1.0nm or more thicker than conventional ones, and the surface quality of the silicon wafer can be stably improved.
Detailed Description
The present invention will be described in detail below, but the present invention is not limited thereto.
As described above, in order to improve DSOD quality, it is necessary to improve surface defects and crystal defects and stabilize the quality of a chemical oxide film formed in a cleaning process. However, in the RCA cleaning, the thickness of the chemical oxide film formed in the SC1 cleaning is very thin, and it is difficult to stabilize the quality of the chemical oxide film, which hinders the improvement of the DSOD quality. Therefore, the improvement of the wafer quality has been a technical problem in the formation of a stable chemical oxide film and a good particle quality when cleaning a silicon wafer.
As a result of intensive studies to solve the above-described problems, the inventors of the present invention have found that chemical oxidation using an oxidizing cleaning liquid can grow the chemical oxide film thickness to 1.0nm by the chemical oxidation after SC1 cleaning or after a cleaning flow in which SC2 cleaning is performed after SC1 cleaning, and that the surface quality of a silicon wafer can be stably improved, and have completed the present invention.
That is, the present invention provides a method for cleaning a silicon wafer, which comprises subjecting a silicon wafer to SC1 cleaning and then cleaning the silicon wafer with an oxidizing cleaning liquid, wherein a chemical oxide film formed on the surface of the silicon wafer by the SC1 cleaning is cleaned with the oxidizing cleaning liquid, and the chemical oxide film is further grown to a thickness of 1.0nm or more.
In such a method of cleaning a silicon wafer, the chemical oxide film formed on the surface of the silicon wafer can be formed to be thicker than conventional methods by 1.0nm or more, and thus the chemical oxide film can be stabilized, and the surface quality of the silicon wafer can be improved.
The method for cleaning a silicon wafer according to the present invention will be described below.
In the cleaning of the silicon wafer of the present invention, the silicon wafer is first subjected to SC1 cleaning. Thus, the adhered particles are detached by etching of the surface of the silicon wafer with the alkaline cleaning solution, and the particles are removed while suppressing re-adhesion to the silicon wafer by further utilizing electrostatic repulsion between the silicon wafer and the particles. Furthermore, SC1 cleaning forms a thin chemical oxide film on the surface of the silicon wafer.
Then, the silicon wafer cleaned with SC1 is cleaned with an oxidizing cleaning liquid, and chemical oxidation is performed. Thus, after SC1 cleaning, the chemical oxide film is formed to have a thickness of 1.0nm or more (preferably 1.2nm or less) thicker than conventional films by cleaning with an oxidizing cleaning solution.
In this case, it is preferable to use ozone water and/or hydrogen peroxide as the cleaning liquid having the oxidizing property. The present invention is particularly effective when such a cleaning liquid is used.
When ozone water is used as the cleaning liquid having oxidizing property, the concentration of ozone is preferably 10ppm or more. If the ozone water concentration is more than 10ppm, oxidation in the surface of the silicon wafer becomes uniform, which is preferable.
When hydrogen peroxide is used as the oxidizing cleaning liquid, the mixing ratio of hydrogen peroxide (30 wt%) to water is preferably H2O2:H2O is 1:20 to 1:5 and the temperature is 60 ℃ or higher. By using such a cleaning liquid, the silicon wafer can be sufficiently oxidized, and the chemical oxide film can be formed thicker than before more reliably.
Further, SC2 cleaning may be performed after the SC1 cleaning and before the cleaning with the oxidizing cleaning liquid. In such a method of cleaning a silicon wafer, the metal impurities on the surface of the silicon wafer can be dissolved and removed, thereby further improving the surface quality of the silicon wafer.
It is preferable that the silicon wafer subjected to SC1 cleaning is a silicon wafer not subjected to DHF cleaning. In such a method of cleaning a silicon wafer, since the chemical oxide film formed on the surface of the silicon wafer is not removed in advance, a sufficient chemical oxide film thickness can be obtained, and therefore the surface quality of the silicon wafer can be more reliably improved.
Examples
The present invention will be described more specifically with reference to the following examples and comparative examples, but the present invention is not limited to these examples.
Comparative example 1
First, a silicon wafer for evaluation is prepared. A clean 300mm silicon wafer without crystal defects called COP or DSOD after mirror polishing was prepared. COP is a pit (pit) -like defect caused by a crystal detected on the surface of a silicon wafer after the mirror-polished silicon wafer is cleaned with a mixed solution of ammonia water and hydrogen peroxide called SC1 cleaning. The pit-like defect is detected together with the particles by measurement of the surface of the silicon wafer by a particle counter. In addition, COP is a cause of deterioration in TDDB (Time Dependent Dielectric Breakdown) or TZDB (Time Zero Dielectric Breakdown) of GOI (Gate Oxide Integrity) evaluation performed as reliability evaluation of an Oxide film. In addition, DSOD defects were also detected in DSOD evaluation by the Cu deposition method. The silicon wafer was evaluated as three pieces, two of which were used for DSOD evaluation and the remaining one was used for evaluation of the chemical oxide film thickness based on XPS.
< cleaning of silicon wafer >
The prepared silicon wafer was subjected to DHF cleaning, followed by cleaning with ozone water, and further SC1 cleaning. For cleaning with ozone water, ozone (O) is used3) 10ppm and 10min at 25 ℃. For SC1 rinse, ammonia (NH) is added4OH) hydrogen peroxide (H)2O2):H2The mixture of 1:1: 10O was used as a washing solution and the mixture was applied at 80 ℃ for 10 min. In the DHF cleaning, a cleaning solution with 3.0 wt% HF was used. NH concentration of the reagent used for preparing the liquid mixture4OH 28 wt%, H2O2Is 30 wt%.
< chemical oxide film evaluation method (DSOD evaluation) >)
The chemical oxide film of the silicon wafer after cleaning was evaluated by DSOD evaluation by Cu deposition method. The DSOD evaluation by the Cu deposition method is described in patent document 4, and is performed as follows. By the cleaning of the silicon wafer, a chemical oxide film (oxide insulating film) is formed on the surface of the silicon wafer, and the oxide insulating film formed on the defective portion of the surface layer of the silicon wafer is broken. Then, Cu is deposited (deposition) at the damaged oxide film portion, thereby identifying the defect. In a solution containing Cu ions, when a voltage is applied to an oxide film formed on the surface of a silicon wafer, a current flows to a portion where the oxide film is deteriorated, and the Cu ions are precipitated as Cu. The deposited Cu was observed and judged to be DSOD. The DSOD can detect not only crystal defects but also processing abnormalities such as scratches and metal contamination that affect the surface quality of a silicon wafer, such as polishing and cleaning.
< method for evaluating chemical oxide film (evaluation of chemical oxide film thickness) >)
Furthermore, the chemical oxide film thickness of the silicon wafer was measured by XPS. XPS is a technique of irradiating a sample surface with X-rays and measuring kinetic energy of photoelectrons emitted from the sample surface to analyze the composition and chemical bonding state of elements constituting the sample surface.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in comparative example 1 was 0.7nm, and the number of DSODs was 31 and 36 for the two silicon wafers subjected to the DSOD evaluation.
Comparative example 2
Except that the cleaning liquid for SC1 cleaning is NH4OH:H2O2:H2Silicon wafers were cleaned in the same manner as in comparative example 1 except for the mixed liquid of O1: 1: 20.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in comparative example 2 was 0.7nm, and the number of DSODs was 34 and 39 for the two silicon wafers subjected to the DSOD evaluation.
Comparative example 3
Cleaning of silicon wafers was performed in the same manner as in comparative example 1, except that SC2 cleaning was performed after SC1 cleaning. For SC2 washes, hydrochloric acid (HCl): H2O2:H21:1: 100OThe solution was used as a cleaning solution and was applied at 80 ℃ for 10 min.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in comparative example 3 was 0.7nm, and the number of DSODs was 29 and 35 for the two silicon wafers subjected to the DSOD evaluation.
Comparative example 4
Except that the cleaning solution for cleaning SC2 is HCl H2O2:H2Silicon wafers were cleaned in the same manner as in comparative example 3 except for the mixed liquid of 1:1: 50.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in comparative example 4 was 0.7nm, and the number of DSODs was 31 and 33 for the two silicon wafers subjected to the DSOD evaluation.
Comparative example 5
Cleaning of silicon wafers was performed in the same manner as in comparative example 1, except that a cleaning liquid with 1.0 wt% of HF was used in DHF cleaning.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in comparative example 5 was 0.7nm, and the number of DSODs was 35 and 40 for the two silicon wafers subjected to the DSOD evaluation.
[ example 1]
Cleaning of silicon wafers was performed in the same manner as in comparative example 1, except that cleaning of silicon wafers was performed with ozone water after SC1 cleaning.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in example 1 was 1.0nm, and the number of DSODs was 13 and 16 for the two silicon wafers subjected to the DSOD evaluation.
[ example 2]
Except for using ozone (O)3) Cleaning of silicon wafers was performed in the same manner as in example 1 except that 30ppm of the cleaning liquid was used as ozone water.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in example 2 was 1.0nm, and the number of DSODs was 11 and 17 for the two silicon wafers subjected to the DSOD evaluation.
[ example 3]
Cleaning of a silicon wafer was performed in the same manner as in example 2, except that the cleaning time with ozone water was set to 1 min.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in example 3 was 1.0nm, and the number of DSODs was 15 and 17 for the two silicon wafers subjected to the DSOD evaluation.
[ example 4]
Cleaning of silicon wafers was performed in the same manner as in example 1, except that SC2 cleaning was performed after SC1 cleaning and before cleaning with ozone water. SC2 cleaning was performed in the same manner as in comparative example 3.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in example 4 was 1.0nm, and the number of DSODs was 16 and 18 for the two silicon wafers subjected to the DSOD evaluation.
[ example 5]
Cleaning of silicon wafers was performed in the same manner as in example 1, except that cleaning with hydrogen peroxide was performed instead of cleaning with ozone water. For cleaning with hydrogen peroxide, H is added2O2:H2The mixture of 1: 10O was used as a washing solution and the mixture was applied at 80 ℃ for 10 min.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in example 5 was 1.0nm, and the number of DSODs was 17 and 19 for the two silicon wafers subjected to the DSOD evaluation.
[ example 6]
Except that H2O2:H2Silicon wafers were cleaned in the same manner as in example 5 except that the mixed solution of O1: 20 was used as a cleaning liquid for cleaning with hydrogen peroxide.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in example 6 was 1.0nm, and the number of DSODs was 13 and 15 for the two silicon wafers subjected to the DSOD evaluation.
[ example 7]
Cleaning of silicon wafers was performed in the same manner as in example 5, except that SC2 cleaning was performed after SC1 cleaning and before cleaning with ozone water, and cleaning with hydrogen peroxide was performed at 60 ℃. SC2 cleaning was performed in the same manner as in comparative example 3.
As a result of the chemical oxide film evaluation, the chemical oxide film thickness in example 7 was 1.0nm, and the number of DSODs was 12 and 16 for the two silicon wafers subjected to the DSOD evaluation.
[ Table 1]
Evaluation results
Comparative example
Examples
The chemical oxide films of comparative examples 1 to 5 were 0.7nm in thickness, and the chemical oxide films of examples 1 to 7 were 1.0nm in thickness. It is presumed that the chemical oxide film of the example was 1.0nm thicker than that of the comparative example, compared to 0.7nm in thickness of the chemical oxide film of the comparative example, because the chemical oxide film of the comparative example was formed by SC1 cleaning, and SC1 cleaning was an equilibrium reaction between oxidation and etching, and thus the chemical oxide film reached an equilibrium state before saturation. On the other hand, it is presumed that in the examples, the chemical oxide film formed by SC1 cleaning was further oxidized with a cleaning liquid having oxidizing property (ozone water, hydrogen peroxide solution), and therefore the chemical oxide film thickness could be made as thick as 1.0 nm.
In addition, it is difficult to make the chemical oxide film thickness thicker than this within the realistic time of manufacturing silicon wafers.
Further, by using the method for cleaning a silicon wafer according to the present invention, the number of DSODs measured by the DSOD evaluation in the examples can be greatly reduced to about half to less than half of the number of DSODs measured by the DSOD evaluation in the comparative examples, and deterioration in quality of the silicon wafer due to cleaning can be suppressed.
The present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments having substantially the same configuration as the technical idea described in the claims of the present invention and producing the same effects are included in the technical scope of the present invention.
Claims (4)
1. A method for cleaning a silicon wafer, comprising cleaning a silicon wafer with an oxidizing cleaning liquid after SC1 cleaning, characterized in that,
and cleaning the chemical oxide film formed on the surface of the silicon wafer by the SC1 cleaning using the oxidizing cleaning liquid, thereby further growing the chemical oxide film to a thickness of 1.0nm or more.
2. The method for cleaning a silicon wafer according to claim 1, wherein ozone water and/or hydrogen peroxide is used as the cleaning liquid having oxidizing property.
3. The method of claim 1 or 2, wherein the SC2 cleaning is performed after the SC1 cleaning and before the cleaning with the oxidizing cleaning solution.
4. The method for cleaning a silicon wafer according to any one of claims 1 to 3, wherein the silicon wafer subjected to the SC1 cleaning is a silicon wafer not subjected to DHF cleaning.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018101949A JP6729632B2 (en) | 2018-05-29 | 2018-05-29 | Silicon wafer cleaning method |
| JP2018-101949 | 2018-05-29 | ||
| PCT/JP2019/013054 WO2019230164A1 (en) | 2018-05-29 | 2019-03-27 | Silicon wafer washing method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112204712A true CN112204712A (en) | 2021-01-08 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201980036009.9A Pending CN112204712A (en) | 2018-05-29 | 2019-03-27 | Method for cleaning silicon wafer |
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|---|---|
| JP (1) | JP6729632B2 (en) |
| KR (1) | KR20210015762A (en) |
| CN (1) | CN112204712A (en) |
| TW (1) | TWI795547B (en) |
| WO (1) | WO2019230164A1 (en) |
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|---|---|---|---|---|
| TW202137529A (en) | 2019-11-18 | 2021-10-01 | 日商索尼半導體解決方案公司 | Solid-state imaging device and electronic device |
| JP2022162915A (en) | 2021-04-13 | 2022-10-25 | 信越半導体株式会社 | Method for cleaning silicon wafer and method for manufacturing silicon wafer with native oxide film |
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| JP2004356416A (en) * | 2003-05-29 | 2004-12-16 | Shin Etsu Handotai Co Ltd | Manufacturing method of silicon epitaxial wafer |
| JP2007073806A (en) * | 2005-09-08 | 2007-03-22 | Toshiba Ceramics Co Ltd | Silicon wafer cleansing method |
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Also Published As
| Publication number | Publication date |
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| JP6729632B2 (en) | 2020-07-22 |
| JP2019207923A (en) | 2019-12-05 |
| TWI795547B (en) | 2023-03-11 |
| TW202004885A (en) | 2020-01-16 |
| WO2019230164A1 (en) | 2019-12-05 |
| KR20210015762A (en) | 2021-02-10 |
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