CN116825625A - Method for improving annealed silicon sheet iron - Google Patents
Method for improving annealed silicon sheet iron Download PDFInfo
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- CN116825625A CN116825625A CN202310938914.1A CN202310938914A CN116825625A CN 116825625 A CN116825625 A CN 116825625A CN 202310938914 A CN202310938914 A CN 202310938914A CN 116825625 A CN116825625 A CN 116825625A
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- polishing
- silicon wafer
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- edge
- improving
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 49
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 49
- 239000010703 silicon Substances 0.000 title claims abstract description 49
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 43
- 238000000034 method Methods 0.000 title claims abstract description 31
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 22
- 238000005498 polishing Methods 0.000 claims abstract description 37
- 238000000227 grinding Methods 0.000 claims abstract description 28
- 239000002184 metal Substances 0.000 claims abstract description 19
- 229910052751 metal Inorganic materials 0.000 claims abstract description 19
- 239000003513 alkali Substances 0.000 claims abstract description 14
- 238000004140 cleaning Methods 0.000 claims abstract description 14
- 239000002253 acid Substances 0.000 claims abstract description 11
- 239000007788 liquid Substances 0.000 claims abstract description 11
- 239000013078 crystal Substances 0.000 claims abstract description 10
- 230000009471 action Effects 0.000 claims abstract description 7
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 4
- 239000010432 diamond Substances 0.000 claims abstract description 4
- 229910003460 diamond Inorganic materials 0.000 claims abstract description 4
- 239000004744 fabric Substances 0.000 claims abstract description 4
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 24
- 229910052786 argon Inorganic materials 0.000 claims description 12
- 230000008569 process Effects 0.000 claims description 10
- 230000007797 corrosion Effects 0.000 claims description 9
- 238000005260 corrosion Methods 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 9
- 238000000137 annealing Methods 0.000 claims description 8
- WGTYBPLFGIVFAS-UHFFFAOYSA-M tetramethylammonium hydroxide Chemical compound [OH-].C[N+](C)(C)C WGTYBPLFGIVFAS-UHFFFAOYSA-M 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 4
- 238000005530 etching Methods 0.000 claims description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 125000000896 monocarboxylic acid group Chemical group 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 6
- 230000007547 defect Effects 0.000 description 5
- 239000010453 quartz Substances 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 230000004913 activation Effects 0.000 description 3
- 239000000969 carrier Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 2
- 238000005108 dry cleaning Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The invention relates to a method for improving annealed silicon sheet iron, which belongs to the technical field of silicon sheet processing and comprises the following operation steps: the first step: slicing the crystal bar along a certain crystal direction after drawing, wherein slicing adopts grinding wheel slicing or diamond wire slicing. And a second step of: and (3) adding grinding liquid to grind through a grinding disc machine, and grinding the damaged layer of the slice through the grinding disc. And a third step of: and chamfering the slices to form round, trapezoid symmetrical or asymmetrical chamfering contours. Fourth step: the slices are etched by acid or alkali or a combination of the two. Fifth step, the method comprises the following steps; and polishing the slice edge by using an edge polishing machine, and polishing the edge by using an edge polishing grinding agent EP4000C under the action of polishing cloth, wherein the pH value of polishing liquid is between 10.5 and 12. Sixth step; and cleaning the silicon wafer. The excellent metal removing effect is realized, the bulk metal level of the silicon wafer is reduced from 2E11 to 2E10, and the edge ring pollution of the bulk metal iron is improved.
Description
Technical Field
The invention relates to the technical field of silicon wafer processing, in particular to a method for improving annealed silicon wafer body iron.
Background
With the increasing shrinking of the size of semiconductor integrated circuits, the requirements for surface defects in device manufacturing are more and more stringent, particularly, the existence of crystal originated particles COP (Crystal originated particle) seriously affects the integrity of GOI, causes defects such as breakdown voltage reduction or electric leakage of devices, and in order to eliminate the defects, the defects such as COP and the like are eliminated by adopting a vertical furnace or a horizontal furnace at 1100-1200 ℃ in the prior art, and a surface clean area is formed by high-temperature annealing, so that a high-quality activation layer is provided for device manufacturing, but the high-quality activation layer is provided with the high-quality activation layer, and the silicon wafer is reversely polluted by bulk metal, particularly boat (quartz, si, siC material) from a silicon wafer bearing part, quartz tubes and the like, so that the bulk metal Fe, cu and Ni are deteriorated. The deterioration of bulk iron can cause the content of metal in the silicon chip to be too high, the quantity of effective carriers is influenced by forming Fe-B pairs, meanwhile, the Fe-B pairs serve as a recombination center of deep energy levels, the carriers are recombined, the mobility of the carriers is reduced, and the device deterioration such as Vt shift of MOS devices is caused.
In the traditional Ar annealing process, for reducing the pollution of bulk metal, the current common means is to carry out dry cleaning at the high temperature of 1100-1250 ℃ on HCl or DCE after a few furnaces or tens of furnaces are produced, or to detach a boat and a quartz tube for wet cleaning, such as HF/HNO3 cleaning, or the combination of the dry cleaning and the wet cleaning, the whole process has long time, and the production efficiency is affected. However, when the silicon wafer is cleaned at high temperature, HCl gas and the like have a relatively strong etching effect on the boat and the quartz tube, and can cause exudation of harmful elements along with time accumulation, so that the service life of the component is reduced, and the silicon wafer is reversely polluted, so that the cleaning effect is poor. The wet cleaning method has the advantages of large dosage of single liquid medicine, long time consumption and serious environmental pollution.
Disclosure of Invention
The invention mainly solves the defects existing in the prior art, provides a method for improving the annealed silicon sheet body iron, realizes excellent metal removal effect, reduces the body metal level of the silicon sheet from 2E11 to 2E10, and improves the edge ring-shaped pollution of the body metal iron.
The technical problems of the invention are mainly solved by the following technical proposal:
a method of improving annealed silicon wafer bulk iron comprising the steps of:
the first step: slicing the crystal bar along a certain crystal direction after drawing, wherein slicing adopts grinding wheel slicing or diamond wire slicing.
And a second step of: and (3) adding grinding liquid to grind through a grinding disc machine, and grinding the damaged layer of the slice through the grinding disc.
And a third step of: and chamfering the slices to form round, trapezoid symmetrical or asymmetrical chamfering contours.
Fourth step: the slices are etched by acid or alkali or a combination of the two.
Fifth step, the method comprises the following steps; and polishing the slice edge by using an edge polishing machine, and polishing the edge by using an edge polishing grinding agent EP4000C under the action of polishing cloth, wherein the pH value of polishing liquid is between 10.5 and 12.
Sixth step; and cleaning the silicon wafer.
Seventh step; and (5) the cleaned silicon wafer enters an Ar furnace tube for annealing.
Preferably, the acid etch is HF/HNO 3 /CH 3 And (3) corroding the damage layer caused by the grinding sheet by using the mixed acid solution such as COOH and the like, and forming a certain back surface shape at the same time, wherein the corrosion time is 20S-5 min.
Preferably, the alkali solution for alkali corrosion is NAOH or KOH solution or TMAH organic alkali solution, and the corrosion is carried out at 45-90 ℃.
Preferably, the polishing machine carries out rough-medium-fine polishing under the action of a rough polishing solution NP6504 and polishing cloths sub-ba 600-sub-ba 800 to obtain a polished silicon wafer with high flatness and good appearance.
Preferably, when the silicon wafer is cleaned, a clean surface is obtained by using a cleaning process of SC1-SC2-O3-HF or a repeated cleaning process of O3+HF of a single-chip cleaner, so that the surface metal reaches the level of 5E8atoms/cm 2.
Preferably, after the silicon wafer enters an Ar furnace tube, argon is introduced, the argon flow is 10-40 slm, the rising speed of a silicon boat is not more than 150mm/min, the furnace inlet temperature is 700 ℃, the heating speed is not more than 5 ℃/min, the temperature is raised to 1000 ℃, 1000-1200 ℃, pure argon is raised at the speed of 1-3 ℃/min, the temperature is kept at 1200 ℃ for 1-4 hours, then the temperature is reduced, the temperature reduction speed is reduced to 700 ℃ at the speed of not more than 5 ℃/min, then the falling speed of the silicon boat is 50-150 mm/min, the furnace is discharged, the water is cooled for more than 25min after the furnace is discharged, and then the silicon wafer is unloaded by a manipulator, so that annealing is completed.
Preferably, a small amount of HCl gas is added at 700-1000 ℃, wherein the flow rate of HCl gas is 0.1-2% of argon gas.
The invention can achieve the following effects:
compared with the prior art, the method for improving the annealed silicon wafer body iron realizes excellent metal removal effect, reduces the body metal level of the silicon wafer from 2E11 to 2E10, and improves the edge ring-shaped pollution of the body metal iron.
Detailed Description
The technical scheme of the invention is further specifically described by the following examples.
Examples: a method of improving annealed silicon wafer bulk iron comprising the steps of:
the first step: slicing the crystal bar along a certain crystal direction after drawing, wherein slicing adopts grinding wheel slicing or diamond wire slicing.
And a second step of: and (3) adding grinding liquid to grind through a grinding disc machine, and grinding the damaged layer of the slice through the grinding disc.
And a third step of: chamfering is carried out on the slices, and a chamfering contour with round, trapezoid symmetry or asymmetry is formed by using rubstones with the same mesh number as 800 1200 3000 in the chamfering process.
The two processes of grinding and chamfering can be interchanged.
Fourth step: the slices are etched by acid or alkali or a combination of the two. Acid etching with HF/HNO 3 /CH 3 And (3) corroding the damage layer caused by the grinding sheet by using the mixed acid solution such as COOH and the like, and forming a certain back surface shape at the same time, wherein the corrosion time is 20S-5 min. The alkali solution for alkali corrosion is NAOH or KOH solution or TMAH organic alkali solution, and the corrosion is carried out at 45-90 ℃.
Fifth step, the method comprises the following steps; and polishing the slice edge by using an edge polishing machine, and polishing the edge by using an edge polishing grinding agent EP4000C under the action of polishing cloth, wherein the pH value of polishing liquid is between 10.5 and 12.
The polishing machine carries out coarse-medium-fine polishing under the action of the coarse polishing liquid NP6504 and polishing cloths suba 600-suba 800 to obtain the polished silicon wafer with high flatness and good appearance.
Sixth step; when the silicon wafer is cleaned, a clean surface is obtained by utilizing the cleaning process of SC1-SC2-O3-HF or the repeated cleaning process of O3+HF of a single-chip cleaner, so that the surface metal reaches the level of 5E8atoms/cm < 2 >.
Seventh step; and (5) the cleaned silicon wafer enters an Ar furnace tube for annealing. After entering an Ar furnace tube, argon is introduced, the argon flow is 10-40 slm, the rising rate of a silicon boat is not more than 150mm/min, the furnace inlet temperature is 700 ℃, the heating rate is increased to 1000 ℃ at a rate not more than 5 ℃/min, a small amount of HCl gas is added at 700-1000 ℃, the gas flow of the HCl gas is 0.1-2% of the argon, 1000-1200 ℃, pure argon is heated at a rate of 1-3 ℃/min, the temperature is kept for 1-4 hours at 1200 ℃, then cooling is carried out, the cooling rate is reduced to 700 ℃ at a rate not more than 5 ℃/min, then the falling rate of the silicon boat is 50-150 mm/min, the furnace outlet is carried out, the water cooling is carried out for more than 25min after the furnace outlet, and then the silicon wafer is unloaded by a manipulator, so that annealing is completed.
In summary, the method for improving the annealed wafer bulk iron achieves excellent metal removal, the wafer bulk metal level is reduced from 2E11 to 2E10, and the edge ring contamination of the bulk metal iron is improved.
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 (7)
1. A method of improving annealed silicon wafer bulk iron comprising the steps of:
the first step: slicing the crystal bar along a certain crystal direction after drawing, wherein slicing is performed by adopting a grinding wheel slice or a diamond wire slice;
and a second step of: grinding by adding grinding liquid through a grinding disc machine, wherein the grinding disc grinds away the damaged layer of the slice;
and a third step of: chamfering the slices to form round, trapezoid symmetrical or asymmetrical chamfering contours;
fourth step: etching the slice by acid or alkali or the combination of the acid and the alkali;
fifth step, the method comprises the following steps; polishing the slice edge, namely polishing the slice edge by using an edge polishing machine and using an edge polishing grinding agent EP4000C, and polishing the edge under the action of polishing cloth, wherein the pH value of polishing liquid is between 10.5 and 12;
sixth step; cleaning the silicon wafer;
seventh step; and (5) the cleaned silicon wafer enters an Ar furnace tube for annealing.
2. A method of improving annealed silicon wafer bulk iron as set forth in claim 1 wherein: acid etching with HF/HNO 3 /CH 3 And (3) corroding the damage layer caused by the grinding sheet by using the mixed acid solution such as COOH and the like, and forming a certain back surface shape at the same time, wherein the corrosion time is 20S-5 min.
3. A method of improving annealed silicon sheet iron according to claim 1 or 2, characterized in that: the alkali solution for alkali corrosion is NAOH or KOH solution or TMAH organic alkali solution, and the corrosion is carried out at 45-90 ℃.
4. A method of improving annealed silicon wafer bulk iron as set forth in claim 1 wherein: the polishing machine carries out coarse-medium-fine polishing under the action of the coarse polishing liquid NP6504 and polishing cloths suba 600-suba 800 to obtain the polished silicon wafer with high flatness and good appearance.
5. A method of improving annealed silicon wafer bulk iron as set forth in claim 1 wherein: when the silicon wafer is cleaned, a clean surface is obtained by utilizing a cleaning process of SC1-SC2-O3-HF or a repeated cleaning process of O3+HF of a single-chip cleaner, so that the surface metal reaches the level of 5E8atoms/cm < 2 >.
6. A method of improving annealed silicon wafer bulk iron as set forth in claim 1 wherein: and after the silicon chip enters an Ar furnace tube, argon is introduced, the argon flow is 10-40 slm, the rising rate of a silicon boat is not more than 150mm/min, the furnace inlet temperature is 700 ℃, the heating rate is increased to 1000 ℃ at a rate not more than 5 ℃/min, 1000-1200 ℃, pure argon is increased at a rate of 1-3 ℃/min, the temperature is kept at 1200 ℃ for 1-4 hours, then the temperature is reduced, the cooling rate is reduced to 700 ℃ at a rate not more than 5 ℃/min, then the falling rate of the silicon boat is 50-150 mm/min, the silicon boat is discharged, the water is cooled for more than 25min after the furnace discharge, and then the silicon chip is unloaded by a manipulator, so that annealing is completed.
7. A method of improving annealed silicon wafer bulk iron as set forth in claim 6 wherein: adding a small amount of HCl gas at 700-1000 ℃, wherein the flow rate of the HCl gas is 0.1-2% of that of argon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310938914.1A CN116825625A (en) | 2023-07-28 | 2023-07-28 | Method for improving annealed silicon sheet iron |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310938914.1A CN116825625A (en) | 2023-07-28 | 2023-07-28 | Method for improving annealed silicon sheet iron |
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| Publication Number | Publication Date |
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| CN116825625A true CN116825625A (en) | 2023-09-29 |
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| CN202310938914.1A Pending CN116825625A (en) | 2023-07-28 | 2023-07-28 | Method for improving annealed silicon sheet iron |
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| CN (1) | CN116825625A (en) |
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- 2023-07-28 CN CN202310938914.1A patent/CN116825625A/en active Pending
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