CN115763240A - Alkali corrosion process for eliminating surface stress of silicon wafer - Google Patents
Alkali corrosion process for eliminating surface stress of silicon wafer Download PDFInfo
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- CN115763240A CN115763240A CN202211403424.3A CN202211403424A CN115763240A CN 115763240 A CN115763240 A CN 115763240A CN 202211403424 A CN202211403424 A CN 202211403424A CN 115763240 A CN115763240 A CN 115763240A
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- alkali
- silicon wafer
- alkali liquor
- heat treatment
- treatment
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- 239000003513 alkali Substances 0.000 title claims abstract description 91
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 67
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 66
- 239000010703 silicon Substances 0.000 title claims abstract description 66
- 238000000034 method Methods 0.000 title claims abstract description 37
- 230000007797 corrosion Effects 0.000 title claims abstract description 8
- 238000005260 corrosion Methods 0.000 title claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 40
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical group [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims abstract description 21
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 13
- 239000008367 deionised water Substances 0.000 claims description 10
- 229910021641 deionized water Inorganic materials 0.000 claims description 10
- 239000007787 solid Substances 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 238000002360 preparation method Methods 0.000 claims description 2
- 238000005530 etching Methods 0.000 claims 3
- 239000002585 base Substances 0.000 claims 1
- 235000012431 wafers Nutrition 0.000 description 47
- 239000007788 liquid Substances 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 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
- 238000005498 polishing Methods 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Mechanical Treatment Of Semiconductor (AREA)
- Weting (AREA)
Abstract
The invention discloses an alkali corrosion process for eliminating surface stress of a silicon wafer. The silicon wafer processing process sequentially comprises slicing, primary alkali liquor heat treatment, chamfering, secondary alkali liquor heat treatment and grinding; wherein, in the first alkali liquor heat treatment, the silicon slice obtained after slicing is immersed into alkali liquor A for treatment, the mass percentage concentration of the alkali liquor A is 15-40%, the temperature is 90-120 ℃, and the treatment time is 8-30s; in the second alkali liquor heat treatment, the chamfered silicon wafer is immersed into alkali liquor B for treatment, the mass percentage concentration of the alkali liquor B is 20-40%, the temperature is 90-120 ℃, and the treatment time is 5-25s. The alkali used in the alkali liquor A and the alkali liquor B is sodium hydroxide or potassium hydroxide. The process of the invention can effectively eliminate the surface stress of the silicon wafer and reduce the loss rate of the silicon wafer in the subsequent chamfering and grinding processes by adding the alkali liquor heat treatment process before and after chamfering the silicon wafer.
Description
Technical Field
The invention relates to an alkali corrosion process for eliminating surface stress of a silicon wafer, belonging to the technical field of semiconductor silicon wafer processing.
Background
Semiconductor silicon chips are widely applied to modern super-large-scale integrated circuits, and the main processing processes include slicing, chamfering, grinding, corroding, polishing and the like. During the slicing process, a mechanical stress damage layer with the depth of about 25-55 μm is generated on the surface of the silicon chip, wherein the edge part is most easily damaged, and the surface stress is mainly concentrated on the edge part of the silicon chip. In the subsequent processing processes of chamfering, lapping and the like, the damage such as edge chipping, cracking and the like of the silicon wafer is easy to occur due to the large residual stress of the surface damage layer, so that the processing yield of the silicon wafer is reduced. During epitaxy or high-temperature oxidation, defects such as slip lines and dislocations may also be caused. The impurity metal ions are also easy to deposit at the stress concentration position, so that the leakage current is large, and the silicon wafer is possibly scrapped.
Therefore, it is necessary to eliminate the surface stress of the silicon wafer after dicing.
Disclosure of Invention
The invention aims to provide an alkali corrosion process for eliminating the surface stress of a silicon wafer, which improves the yield of the silicon wafer in the subsequent chamfering and grinding processes.
In order to achieve the purpose, the invention adopts the following technical scheme:
an alkali corrosion process for eliminating surface stress of a silicon wafer, wherein the processing process of the silicon wafer sequentially comprises slicing, primary alkali liquor heat treatment, chamfering, secondary alkali liquor heat treatment and grinding; wherein, in the first alkali liquor heat treatment, the silicon slice obtained after slicing is immersed into an alkali liquor A for treatment, the mass percentage concentration of the alkali liquor A is 15-40%, the temperature is 90-120 ℃, and the treatment time is 8-30s; in the second alkali liquor heat treatment, the chamfered silicon wafer is immersed into alkali liquor B for treatment, the mass percentage concentration of the alkali liquor B is 20-40%, the temperature is 90-120 ℃, and the treatment time is 5-25s.
In the method of the invention, the alkali selected for the alkali liquor A and the alkali liquor B can be strong alkali such as sodium hydroxide, potassium hydroxide and the like. The preparation method of the alkali liquor comprises the following steps: dissolving solid alkali in deionized water at 20-30 deg.c and heating as required.
In the method, the silicon wafer is respectively subjected to heat treatment by adopting alkali liquor before and after chamfering, and the surface stress of the silicon wafer can be eliminated by controlling the concentration, the temperature and the treatment time of the alkali liquor, so that the yield of the silicon wafer in the chamfering and grinding processes is improved. When the concentration of the alkali liquor is low, the time for alkali liquor treatment is long, which is not beneficial to actual production; when the temperature is constant, the alkali liquor treatment time is too long, the yield is not obviously improved, and the processing efficiency is also influenced. When the temperature of the alkali liquor is lower, the aim of eliminating the surface stress of the silicon wafer cannot be achieved.
Preferably, in the first lye heat treatment, the concentration of the lye A is higher than 20%, preferably between 20% and 40%, the temperature is higher than 90 ℃, preferably between 100 and 120 ℃, and the treatment time is longer than 8s, preferably between 10 and 30s. In the second alkali liquor heat treatment, the concentration of the alkali liquor B is higher than 20%, preferably 20% -35%, the temperature is higher than 90 ℃, preferably 100-120 ℃, and the treatment time is longer than 5s, preferably 10-20s.
The invention has the beneficial effects that:
the process of the invention can effectively eliminate the surface stress of the silicon wafer and reduce the loss rate of the silicon wafer in the subsequent chamfering and grinding processes by adding the alkali liquor heat treatment process before and after chamfering the silicon wafer.
The process is suitable for the processing of 5-inch, 6-inch, 8-inch and 12-inch silicon wafers, is easy to operate and has low required cost.
Drawings
FIG. 1 is a schematic diagram of a conventional silicon wafer slicing, chamfering and grinding process.
FIG. 2 is a schematic view of the processing flow of slicing, chamfering and grinding a silicon wafer according to an embodiment of the present invention.
Detailed Description
The present invention is further described in detail below with reference to the drawings and examples, but the scope of the present invention is not limited thereto.
As shown in fig. 1, slicing, chamfering, and grinding are sequentially performed in a conventional silicon wafer processing flow. As shown in FIG. 2, the silicon wafer processing flow involved in the practice of the present invention introduces the alkali treatment steps before and after chamfering, respectively.
Example 1
Processing a 5-inch silicon wafer by using a concentrated alkali heat treatment process before and after chamfering the silicon wafer, adding industrial solid alkali (KOH) into deionized water at 25 ℃ to prepare 20% alkali liquor A1, and heating to 100 ℃; immersing the sliced silicon wafer into hot alkali liquor A1, carrying out heat treatment for 10s, and taking out; chamfering according to the requirements of technical specifications; adding industrial solid alkali into deionized water at 25 deg.C to obtain 25% alkali solution B1, and heating to 100 deg.C; and immersing the chamfered silicon wafer into hot alkali liquid B1, carrying out heat treatment for 5s, and taking out the silicon wafer. Specific parameters are shown in table 1.
Example 2
Processing a 6-inch silicon wafer by using a concentrated alkali heat treatment process before and after chamfering the silicon wafer, adding industrial solid alkali (KOH) into deionized water at 25 ℃ to prepare 25% alkali liquor A2, and heating to 105 ℃; immersing the sliced silicon wafer into hot alkali liquor A2, carrying out heat treatment for 15s, and taking out; chamfering according to the requirements of technical specifications; adding industrial solid alkali into deionized water at 25 deg.C to obtain 30% alkali solution B2, and heating to 105 deg.C; and immersing the chamfered silicon wafer into hot alkali liquid B2, carrying out heat treatment for 10s, and taking out the silicon wafer. Specific parameters are shown in table 1.
Example 3
Processing an 8-inch silicon wafer by using a concentrated alkali heat treatment process before and after chamfering the silicon wafer, adding industrial solid alkali (KOH) into deionized water at 25 ℃ to prepare 30% alkali liquor A3, and heating to 110 ℃; immersing the sliced silicon wafer into hot alkali liquor A3, carrying out heat treatment for 20s, and taking out; chamfering according to the requirements of technical specifications; adding industrial solid alkali into deionized water at 25 deg.C to obtain 35% alkali solution B3, and heating to 110 deg.C; and immersing the chamfered silicon wafer into hot alkali liquid B3, carrying out heat treatment for 15s, and taking out the silicon wafer. Specific parameters are shown in table 1.
Example 4
Processing a 12-inch silicon wafer by using a concentrated alkali heat treatment process before and after chamfering the silicon wafer, adding industrial solid alkali (KOH) into deionized water at 25 ℃ to prepare 35% alkali liquor A4, and heating to 120 ℃; immersing the sliced silicon wafer into hot alkali liquor, carrying out heat treatment for 30s, and taking out; chamfering according to the requirements of technical specifications; adding industrial solid alkali into deionized water at 25 deg.C to obtain 40% alkali solution B4, and heating to 120 deg.C; and immersing the chamfered silicon wafer into hot alkali liquid B4, carrying out heat treatment for 20s, and taking out the silicon wafer. Specific parameters are shown in table 1.
Table 1 examples of the invention are compared to conventional processing.
Table 2 example of the present invention is compared to conventional process yields.
| Type of process | Number of working operations | Yield of chamfer | Grinding yield |
| Conventional process | 5000 | 98.62％ | 99.03％ |
| Example 1 | 5000 | 99.31％ | 99.53％ |
| Example 2 | 5000 | 99.25％ | 99.48％ |
| Example 3 | 5000 | 99.39％ | 99.57％ |
| Example 4 | 5000 | 99.23％ | 99.37％ |
As shown in Table 2, the silicon wafers processed by the above embodiments have significantly higher average processing yield than the unprocessed silicon wafers in the subsequent chamfering and grinding processes, and effectively improve the utilization rate of the silicon wafers.
The embodiments of the present invention are preferred embodiments of the present invention, and do not limit the scope of the claims. All such variations and modifications are intended to be included within the scope of the invention as defined in the appended claims.
Claims (5)
1. An alkali corrosion process for eliminating the surface stress of a silicon wafer is characterized in that the silicon wafer processing process sequentially comprises slicing, primary alkali liquor heat treatment, chamfering, secondary alkali liquor heat treatment and grinding; wherein, in the first alkali liquor heat treatment, the silicon slice obtained after slicing is immersed into an alkali liquor A for treatment, the mass percentage concentration of the alkali liquor A is 15-40%, the temperature is 90-120 ℃, and the treatment time is 8-30s; in the second alkali liquor heat treatment, the chamfered silicon wafer is immersed into alkali liquor B for treatment, the mass percentage concentration of the alkali liquor B is 20-40%, the temperature is 90-120 ℃, and the treatment time is 5-25s.
2. The alkali etching process for eliminating the surface stress of the silicon wafer as claimed in claim 1, wherein the alkali selected from the alkali solution A and the alkali solution B is sodium hydroxide or potassium hydroxide.
3. The alkali corrosion process for eliminating the surface stress of the silicon wafer according to claim 2, wherein the preparation method of the alkali solution comprises the following steps: the solid base is dissolved in deionized water at 20-30 deg.C and heated to the desired temperature.
4. The alkali etching process for eliminating the surface stress of the silicon wafer according to claim 1, wherein in the first alkali solution heat treatment, the concentration of the alkali solution A is 20% -40%, the temperature is 100-120 ℃, and the treatment time is 10-30s.
5. The alkali etching process for eliminating the surface stress of the silicon wafer according to claim 1, wherein in the second alkali solution heat treatment, the concentration of the alkali solution B is 20% -35%, the temperature is 100-120 ℃, and the treatment time is 10-20s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211403424.3A CN115763240A (en) | 2022-11-10 | 2022-11-10 | Alkali corrosion process for eliminating surface stress of silicon wafer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211403424.3A CN115763240A (en) | 2022-11-10 | 2022-11-10 | Alkali corrosion process for eliminating surface stress of silicon wafer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115763240A true CN115763240A (en) | 2023-03-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211403424.3A Pending CN115763240A (en) | 2022-11-10 | 2022-11-10 | Alkali corrosion process for eliminating surface stress of silicon wafer |
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| CN (1) | CN115763240A (en) |
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- 2022-11-10 CN CN202211403424.3A patent/CN115763240A/en active Pending
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