CN117732770A - Processing method for improving metal pollution of edge of silicon polishing sheet - Google Patents
Processing method for improving metal pollution of edge of silicon polishing sheet Download PDFInfo
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- CN117732770A CN117732770A CN202311634287.9A CN202311634287A CN117732770A CN 117732770 A CN117732770 A CN 117732770A CN 202311634287 A CN202311634287 A CN 202311634287A CN 117732770 A CN117732770 A CN 117732770A
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- polishing sheet
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 64
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 64
- 239000010703 silicon Substances 0.000 title claims abstract description 64
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 62
- 239000002184 metal Substances 0.000 title claims abstract description 56
- 238000005498 polishing Methods 0.000 title claims abstract description 40
- 238000003672 processing method Methods 0.000 title claims abstract description 11
- 238000004140 cleaning Methods 0.000 claims abstract description 23
- 238000012545 processing Methods 0.000 claims abstract description 22
- 239000012535 impurity Substances 0.000 claims abstract description 18
- 239000003513 alkali Substances 0.000 claims abstract description 16
- 238000005260 corrosion Methods 0.000 claims abstract description 14
- 230000007797 corrosion Effects 0.000 claims abstract description 14
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 8
- 239000003814 drug Substances 0.000 claims abstract description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims abstract description 5
- 238000012360 testing method Methods 0.000 claims abstract description 5
- 238000001035 drying Methods 0.000 claims abstract description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 57
- 238000004458 analytical method Methods 0.000 claims description 15
- 239000000126 substance Substances 0.000 claims description 15
- 238000011109 contamination Methods 0.000 claims description 14
- 239000002344 surface layer Substances 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- 150000002500 ions Chemical class 0.000 claims description 7
- 238000000295 emission spectrum Methods 0.000 claims description 6
- 238000003384 imaging method Methods 0.000 claims description 6
- 238000001228 spectrum Methods 0.000 claims description 6
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 5
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 5
- 238000005516 engineering process Methods 0.000 claims description 5
- 229910052729 chemical element Inorganic materials 0.000 claims description 3
- 238000009826 distribution Methods 0.000 claims description 3
- 238000010894 electron beam technology Methods 0.000 claims description 3
- 238000000921 elemental analysis Methods 0.000 claims description 3
- 238000002189 fluorescence spectrum Methods 0.000 claims description 3
- 239000012212 insulator Substances 0.000 claims description 3
- 238000010884 ion-beam technique Methods 0.000 claims description 3
- 238000005211 surface analysis Methods 0.000 claims description 3
- 238000010183 spectrum analysis Methods 0.000 claims description 2
- 238000010998 test method Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 5
- 238000005507 spraying Methods 0.000 abstract description 3
- 235000012431 wafers Nutrition 0.000 description 22
- 239000000243 solution Substances 0.000 description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000012670 alkaline solution Substances 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Abstract
The invention relates to a processing method for improving metal pollution at the edge of a silicon polishing sheet, which belongs to the technical field of silicon wafer processing and comprises the following operation steps: the first step: and (3) performing alkali corrosion processing on the silicon polished wafer subjected to chamfering processing. And a second step of: and cleaning the silicon polished wafer after alkali corrosion, and performing edge polishing. And a third step of: after front polishing, single-sided cleaning is carried out, the cleaning liquid medicine is SC1 solution and HF solution, and the silicon polishing sheet is respectively cleaned in an SC1 cleaning tank and an HF cleaning tank. Fourth step: and (5) spraying pure water on the silicon polished wafer after single-sided cleaning, and completing a nitrogen heating and drying process. Fifth step: surface metal testing was performed. Has the characteristics of convenient operation, good effect, time and labor saving and good quality stability. Solves the problem that the edge of the silicon polished wafer is easy to be polluted by metal impurities. The condition that the product is unqualified due to the fact that the metal content of the surface of the silicon polishing sheet exceeds the standard is avoided.
Description
Technical Field
The invention relates to the technical field of silicon wafer processing, in particular to a processing method for improving metal pollution at the edge of a silicon polishing wafer.
Background
Silicon material is the main substrate material for manufacturing very large scale integrated circuits, and along with the rapid development of the semiconductor industry, the precision requirement on the substrate material is higher and higher, and particularly the edge state requirement on a silicon polished wafer is stricter and stricter. For silicon polished sheets with diameters of more than 6 inches, especially 8 inches and 12 inches, the edges of the silicon sheets are generally required to be polished during substrate processing, so that defects such as slip lines, epitaxial faults and the like are not generated at the edges of the silicon sheets during epitaxy, and the yield of epitaxial sheets or devices is improved.
Metal impurity contamination is one of the main elements affecting semiconductor wafers, while iron is the most common metal impurity. Sources of iron contamination mainly include iron impurities contained in raw materials, diffusion during crystal pulling, and introduction of a polishing sheet processing process (cutting, etching, polishing, cleaning, heat treatment, etc.).
In the processing process of polishing sheets, metal impurity pollution is easily introduced due to imperfect processing technology and unavoidable contact between wafers and equipment, particularly the edges of the wafers, so that the metal content on the surfaces exceeds the standard, and the products are unqualified. The normal use requirement cannot be met, and the electronic components cannot be further processed, so that waste is caused.
Disclosure of Invention
The invention mainly solves the defects existing in the prior art, and provides the processing method for improving the metal pollution at the edge of the silicon polishing sheet, which has the characteristics of convenient operation, good effect, time and labor saving and good quality stability. Solves the problem that the edge of the silicon polished wafer is easy to be polluted by metal impurities. The condition that the product is unqualified due to the fact that the metal content of the surface of the silicon polishing sheet exceeds the standard is avoided.
The technical problems of the invention are mainly solved by the following technical proposal:
a processing method for improving metal pollution at the edge of a silicon polished wafer comprises the following operation steps:
the first step: and (3) performing alkali corrosion processing on the silicon polished wafer subjected to chamfering processing.
And a second step of: and (3) after the silicon polishing sheet subjected to alkali corrosion is cleaned, performing edge polishing for 3-4 min, so that the edge of the silicon polishing sheet is sufficiently polished, and the possibly introduced metal impurity pollution is completely removed.
And a third step of: after polishing the front surface for 2-4 min, cleaning the front surface for 1-3 min, wherein the cleaned liquid medicine is SC1 solution and HF solution, and the silicon polishing sheet is cleaned in an SC1 cleaning tank and an HF cleaning tank respectively.
Fourth step: and (5) spraying pure water on the silicon polished wafer after single-sided cleaning, and completing a nitrogen heating and drying process.
Fifth step: surface metal test is carried out to ensure that metal impurities of the silicon polishing sheet are effectively controlled.
Preferably, the liquid medicine used for alkali corrosion processing is KOH solution, the mass concentration is 40-50%, and the processing time is 40-80 min.
Preferably, the alkali etching process achieves an increase in the removal of the silicon polished wafer surface to about 60 to 80 a um a, ensuring effective removal of metallic impurities from the previous process.
Preferably, NH4OH: H2O2: h2o=1 in SC1 solution: 2: (10-30); the concentration of the HF solution is 1-3%.
Since SC1 is an alkaline solution of H2O2 and NH4OH, organic contamination becomes a water-soluble compound by the strong oxidation of H2O2 and dissolution of NH4OH, which is eliminated with the rinse of deionized water. Meanwhile, the SC1 solution has strong oxidizing property and complexing property, can oxidize Cr, cu, zn, ag, ni, co, ca, fe, mg and the like to make the SC become high-valence ions, and then further reacts with alkali to generate soluble complex compounds which are removed along with the flushing of deionized water. Therefore, the SC-1 liquid is used for cleaning the polished wafer, so that not only can organic contamination be removed, but also certain metal contamination can be removed. Better cleaning results are obtained when using the SC1 solution in combination with megasonic cleaning.
As preferable methods for testing the surface metal of the silicon polished wafer, there are ICP method, XPS method, SIMS method, AES method or SEM/EDS combined analysis method.
Preferably, the ICP method uses high-frequency plasma excitation to analyze atomic emission spectra in a sample, and measures 20 or more metal elements, and is suitable for analyzing metal elements in a variety of materials.
Preferably, the XPS method is a surface analysis method for determining the content and chemical state of an element by fluorescence spectrum of the surface element, determining the content and chemical state of the element by detecting the electron spectrum change of the surface layer of the sample, and detecting the contents of a plurality of elements; the XPS method can accurately detect the metal content of the surface of the silicon wafer, especially the condition of low element content of the surface layer.
Preferably, the SIMS method is a high-sensitivity elemental analysis method that detects a small elemental content and a light elemental content; bombarding the surface of the sample by an ion beam to enable surface atoms to leave the surface and form ion emission, and then detecting an ion emission spectrum to determine the content and the position of elements; the SIMS method is suitable for detecting samples with low concentration of metal and insulator surface.
Preferably, the AES method is a surface element analysis technique capable of detecting light elements, medium and heavy elements, and inert elements, and obtaining chemical state and surface morphology information of the elements; the AES method uses a laser beam or an electron beam to excite the surface of a sample, generates high-energy electrons, and performs analysis.
Preferably, SEM/EDS combined analysis is a high resolution imaging and spectroscopy technique; the SEM provides microscopic images, the EDS can provide element spectrograms, and structural information and chemical component information are given through the combination of the SEM imaging and the EDS energy spectrum and are used for detecting chemical components on the surface of the material; SEM/EDS combined analysis is suitable for detecting surface layers with extremely low element content and gives the distribution of chemical elements.
The invention can achieve the following effects:
compared with the prior art, the processing method for improving the metal pollution at the edge of the silicon polishing sheet has the characteristics of convenience in operation, good effect, time and labor saving and good quality stability. Solves the problem that the edge of the silicon polished wafer is easy to be polluted by metal impurities. The condition that the product is unqualified due to the fact that the metal content of the surface of the silicon polishing sheet exceeds the standard is avoided.
Detailed Description
The technical scheme of the invention is further specifically described by the following examples.
Examples: a processing method for improving metal pollution at the edge of a silicon polished wafer comprises the following operation steps:
the first step: and (3) performing alkali corrosion processing on the silicon polished wafer subjected to chamfering processing. The liquid medicine used in the alkali corrosion processing is KOH solution with the mass concentration of 40-50% and the processing time of 40-80 min. The alkali corrosion processing reaches the surface removal amount of the silicon polished wafer to be increased to about 60-80 and um, so that the metal impurities left by the previous working procedure can be effectively removed.
And a second step of: and (3) after the silicon polishing sheet subjected to alkali corrosion is cleaned, performing edge polishing for 3-4 min, so that the edge of the silicon polishing sheet is sufficiently polished, and the possibly introduced metal impurity pollution is completely removed.
And a third step of: after polishing the front surface for 2-4 min, cleaning the front surface for 1-3 min, wherein the cleaned liquid medicine is SC1 solution and HF solution, and the silicon polishing sheet is cleaned in an SC1 cleaning tank and an HF cleaning tank respectively. NH4OH: H2O2: h2o=1 in SC1 solution: 2: (10-30); the concentration of the HF solution is 1-3%.
Fourth step: and (5) spraying pure water on the silicon polished wafer after single-sided cleaning, and completing a nitrogen heating and drying process.
Fifth step: surface metal test is carried out to ensure that metal impurities of the silicon polishing sheet are effectively controlled.
The surface metal test method of the silicon polished wafer comprises an ICP method, an XPS method, a SIMS method, an AES method or an SEM/EDS combined analysis method. The ICP method utilizes the atomic emission spectrum in the high-frequency plasma excited sample to analyze, and determines more than 20 metal elements, and is suitable for analyzing the metal elements in various materials.
The XPS method is a surface analysis method for determining the content and chemical state of elements through fluorescence spectrum of surface elements, and is used for determining the content and chemical state of the elements by detecting the electron spectrum change of the surface layer of a sample, and detecting the content of a plurality of elements; the XPS method can accurately detect the metal content of the surface of the silicon wafer, especially the condition of low element content of the surface layer.
The SIMS method is a high-sensitivity elemental analysis method, which detects very small element content and light element content; bombarding the surface of the sample by an ion beam to enable surface atoms to leave the surface and form ion emission, and then detecting an ion emission spectrum to determine the content and the position of elements; the SIMS method is suitable for detecting samples with low concentration of metal and insulator surface.
The AES method is a surface element analysis technology, can detect light elements, medium and heavy elements and inert elements, and can obtain the chemical state and surface morphology information of the elements; the AES method uses a laser beam or an electron beam to excite the surface of a sample, generates high-energy electrons, and performs analysis.
SEM/EDS combined analysis is a high resolution imaging and energy spectrum analysis technology; the SEM provides microscopic images, the EDS can provide element spectrograms, and structural information and chemical component information are given through the combination of the SEM imaging and the EDS energy spectrum and are used for detecting chemical components on the surface of the material; SEM/EDS combined analysis is suitable for detecting surface layers with extremely low element content and gives the distribution of chemical elements.
The surface metal impurity pollution introduced by the previous process is fully removed by increasing the alkali corrosion time; and then the edge metal content is improved by prolonging the edge polishing time. The surface metal level of the finally obtained polishing sheet is within 1E9 atoms/cm 2, and particularly the edge area is greatly improved.
In conclusion, the processing method for improving the metal pollution at the edge of the silicon polishing sheet has the characteristics of convenience in operation, good effect, time and labor saving and good quality stability. Solves the problem that the edge of the silicon polished wafer is easy to be polluted by metal impurities. The condition that the product is unqualified due to the fact that the metal content of the surface of the silicon polishing sheet exceeds the standard is avoided.
The above embodiments are merely examples of the present invention, but the present invention is not limited thereto, and any changes or modifications made by those skilled in the art are included in the scope of the present invention.
Claims (10)
1. A processing method for improving metal pollution at the edge of a silicon polished wafer is characterized by comprising the following operation steps:
the first step: performing alkali corrosion processing on the silicon polished wafer subjected to chamfering processing;
and a second step of: after the silicon polishing sheet subjected to alkali corrosion is cleaned, edge polishing is carried out for 3-4 min, so that the edge polishing of the silicon polishing sheet is complete, and metal impurity pollution possibly introduced is completely removed;
and a third step of: after front polishing for 2-4 min, single-sided cleaning is carried out for 1-3 min, the cleaning liquid medicine is SC1 solution and HF solution, and the silicon polishing sheet is respectively cleaned in an SC1 cleaning tank and an HF cleaning tank;
fourth step: after single-sided cleaning, the silicon polishing sheet is sprayed with pure water and the nitrogen heating and drying process is completed;
fifth step: surface metal test is carried out to ensure that metal impurities of the silicon polishing sheet are effectively controlled.
2. The method for improving metal contamination of the edge of a silicon wafer according to claim 1, wherein: the liquid medicine used in the alkali corrosion processing is KOH solution with the mass concentration of 40-50% and the processing time of 40-80 min.
3. The processing method for improving metal contamination of the edge of a silicon polishing sheet according to claim 2, wherein: the alkali corrosion processing reaches the surface removal amount of the silicon polished wafer to be increased to about 60-80 and um, so that the metal impurities left by the previous working procedure can be effectively removed.
4. The method for improving metal contamination of the edge of a silicon wafer according to claim 1, wherein: NH4OH: H2O2: h2o=1 in SC1 solution: 2: (10-30); the concentration of the HF solution is 1-3%.
5. The method for improving metal contamination of the edge of a silicon wafer according to claim 1, wherein: the surface metal test method of the silicon polished wafer comprises an ICP method, an XPS method, a SIMS method, an AES method or an SEM/EDS combined analysis method.
6. The method for improving edge metal contamination of a silicon wafer according to claim 5, wherein: the ICP method utilizes the atomic emission spectrum in the high-frequency plasma excited sample to analyze, and determines more than 20 metal elements, and is suitable for analyzing the metal elements in various materials.
7. The method for improving edge metal contamination of a silicon wafer according to claim 5, wherein: the XPS method is a surface analysis method for determining the content and chemical state of elements through fluorescence spectrum of surface elements, and is used for determining the content and chemical state of the elements by detecting the electron spectrum change of the surface layer of a sample, and detecting the content of a plurality of elements; the XPS method can accurately detect the metal content of the surface of the silicon wafer, especially the condition of low element content of the surface layer.
8. The method for improving edge metal contamination of a silicon wafer according to claim 5, wherein: the SIMS method is a high-sensitivity elemental analysis method, which detects very small element content and light element content; bombarding the surface of the sample by an ion beam to enable surface atoms to leave the surface and form ion emission, and then detecting an ion emission spectrum to determine the content and the position of elements; the SIMS method is suitable for detecting samples with low concentration of metal and insulator surface.
9. The method for improving edge metal contamination of a silicon wafer according to claim 5, wherein: the AES method is a surface element analysis technology, can detect light elements, medium and heavy elements and inert elements, and can obtain the chemical state and surface morphology information of the elements; the AES method uses a laser beam or an electron beam to excite the surface of a sample, generates high-energy electrons, and performs analysis.
10. The method for improving edge metal contamination of a silicon wafer according to claim 5, wherein: SEM/EDS combined analysis is a high resolution imaging and energy spectrum analysis technology; the SEM provides microscopic images, the EDS can provide element spectrograms, and structural information and chemical component information are given through the combination of the SEM imaging and the EDS energy spectrum and are used for detecting chemical components on the surface of the material; SEM/EDS combined analysis is suitable for detecting surface layers with extremely low element content and gives the distribution of chemical elements.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311634287.9A CN117732770A (en) | 2023-12-01 | 2023-12-01 | Processing method for improving metal pollution of edge of silicon polishing sheet |
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| CN202311634287.9A CN117732770A (en) | 2023-12-01 | 2023-12-01 | Processing method for improving metal pollution of edge of silicon polishing sheet |
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| CN117732770A true CN117732770A (en) | 2024-03-22 |
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| CN202311634287.9A Pending CN117732770A (en) | 2023-12-01 | 2023-12-01 | Processing method for improving metal pollution of edge of silicon polishing sheet |
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- 2023-12-01 CN CN202311634287.9A patent/CN117732770A/en active Pending
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