CN111872780A - Method for improving edge warping of silicon wafer - Google Patents
Method for improving edge warping of silicon wafer Download PDFInfo
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- CN111872780A CN111872780A CN202010698929.1A CN202010698929A CN111872780A CN 111872780 A CN111872780 A CN 111872780A CN 202010698929 A CN202010698929 A CN 202010698929A CN 111872780 A CN111872780 A CN 111872780A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
- B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
- B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
- B24B9/065—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of thin, brittle parts, e.g. semiconductors, wafers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
- B24B37/07—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool
- B24B37/08—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool for double side lapping
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- Mechanical Treatment Of Semiconductor (AREA)
Abstract
The present invention relates to the field of semiconductors. A method for improving the edge warping of a silicon wafer is characterized in that the following grinding steps are sequentially carried out on the sliced silicon wafer: grinding the edge of a silicon wafer by using a chamfering grinding wheel, and grinding the diameter of a primary chamfer, wherein the grinding amount of the diameter of the primary chamfer is A, and A is 230-270 mu m; step two, carrying out primary double-sided grinding through a wide grinding wheel, wherein the removal amount of the width of the primary double-sided grinding is B, and the B is 28-32 mu m; grinding the edge of the silicon wafer by using a chamfering grinding wheel, and grinding the diameter of the secondary chamfer, wherein the grinding amount of the diameter of the secondary chamfer is C, and C is 730-770 μm; step four, carrying out secondary double-sided grinding through a wide grinding wheel, wherein the removal amount of the width of the secondary double-sided grinding is D, and D is 33-37 mu m; a + C1000 μm, B + D65 μm. After the grinding step is adopted, the problem of width caused by warping of the edge of the silicon wafer is effectively solved.
Description
Technical Field
The invention relates to the field of semiconductors, in particular to a silicon wafer grinding method.
Background
The positions of the slices with larger warping are mainly concentrated at the steel wire entry point and near the steel wire exit point. According to past experience and the current level of wire cutting, edge warping is difficult to further effectively improve.
The traditional silicon wafer chamfering processing mode is that a metal grinding wheel directly grinds the diameter, the removal amount is about 1000um, and the diameter is ground to meet the standard requirement. Chamfering is performed according to the traditional processing mode, the defect rate of edge warping is high, and the difference of the width of a warping point is large when chamfering is performed due to edge warping. The width is an extremely important parameter index and hard requirement for customer requirements, the width of the same side of a customer generally cannot exceed 40um, the width of the front side and the back side of the same position cannot exceed 100um, however, the width of the front side and the back side of the same position of the traditional chamfering processing mode exceeds more than 150um, especially the warping of an entry point and an exit point, the width exceeds more than 200um, and the customer is scrapped.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a method for improving the edge warping of a silicon wafer, so as to solve at least one technical problem.
The technical scheme of the invention is as follows: a method for improving the edge warping of a silicon wafer is characterized in that the following grinding steps are sequentially carried out on the sliced silicon wafer:
grinding the edge of a silicon wafer by using a chamfering grinding wheel, and grinding the diameter of a primary chamfer, wherein the grinding amount of the diameter of the primary chamfer is A, and A is 230-270 mu m;
step two, carrying out primary double-sided grinding through a wide grinding wheel, wherein the removal amount of the width of the primary double-sided grinding is B, and the B is 28-32 mu m;
grinding the edge of the silicon wafer by using a chamfering grinding wheel, and grinding the diameter of the secondary chamfer, wherein the grinding amount of the diameter of the secondary chamfer is C, and C is 730-770 μm;
step four, carrying out secondary double-sided grinding through a wide grinding wheel, wherein the removal amount of the width of the secondary double-sided grinding is D, and D is 33-37 mu m;
A+C＝1000μm,B+D＝65μm。
after the grinding step is adopted, the problem of width caused by warping of the edge of the silicon wafer is effectively solved. The width is confirmed by adopting different grinding modes, the improvement effect of the range on the edge warping is most obvious, and the width difference of the positions of the cut-in point and the cut-out point can be within 100 um.
Preferably, A is 250 μm, B is 30 μm, C is 750 μm and D is 25 μm.
By adopting the group of data, the wide difference value of the positions of the cut-in point and the cut-out point can be within 80 um.
Preferably, A is 230 μm, B is 28 μm, C is 770 μm and D is 27 μm.
By adopting the group of data, the wide difference value of the positions of the cut-in point and the cut-out point can be within 95 um.
A is 270 μm, B is 32 μm, C is 730 μm, and D is 22 μm.
By adopting the group of data, the wide difference value of the positions of the cut-in point and the cut-out point can be within 95 um.
Further preferably, after grinding, a chamfer profilometer is used for measuring the size parameters of the silicon wafer, wherein the size parameters of the silicon wafer comprise the width of a chamfer on the silicon wafer, the width of a lower chamfer on the silicon wafer, the chamfer angle under the silicon wafer and the thickness of the silicon wafer.
The warping condition of the edge of the ground silicon wafer can be known conveniently, and the selective inspection of the silicon wafer can be realized.
Further preferably, the wide grinding wheel is a ceramic disc. The main component of the alloy is Al2O3And the purity is more than 99%. The problem of heavy metal Fe pollution caused by the traditional cast iron disc is avoided. The heavy metal impurity Fe can cause the most serious heavy metal pollution to the silicon wafer, the potential barrier formed by dislocation of oxidation induced stacking fault is reduced, the device failure can be seriously influenced, and the yield of the chip is greatly reduced.
Further preferably, the cutting fluid used in the first step is pure water.
The grinding liquid used in the second step comprises 40Kg of grinding powder, 4.2L of P-37 and 70L of water, the granularity of the grinding powder is 7.5um, more than 99 percent of the grinding powder is Al2O3. The grind powder may be selected as FO # 1000.
And the cutting fluid used in the third step is pure water.
The grinding liquid used in the fourth step comprises 40Kg of grinding powder, 4.2L of P-37 and 70L of water, the granularity of the grinding powder is 7.5um, more than 99 percent of the grinding powder is Al2O3. The grind powder may be selected as FO # 1000.
Further preferably, the outer edge of the silicon wafer comprises an arc-shaped outer peripheral area and a linear flat edge area which are sequentially connected;
in the first step, when the arc-shaped peripheral area is ground, the autorotation speed of the silicon wafer is 19mm/s, when the linear flat edge area is ground, the translation speed of the silicon wafer is 9mm/s, and the autorotation speed of the grinding head is 4000 rpm/min. (ii) a
In the second step, the rotating speed of the upper grinding fixed disc is 11rpm/min, the rotating speed of the lower fixed disc is 33rpm/min, and the time is 4-4.3 min;
in the third step, when the arc-shaped peripheral area is ground, the rotation speed of the silicon wafer is 20mm/s, when the linear flat edge area is ground, the translation speed of the silicon wafer is 10mm/s, and the rotation speed of the grinding head is 4500 rpm/min;
in the fourth step, the rotating speed of the upper grinding fixed disc is 11rpm/min, the rotating speed of the lower fixed disc is 33rpm/min, and the time is 4.5-5 min.
Drawings
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a cross-sectional view of the outer edge of a silicon wafer according to the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings.
In specific embodiment 1, referring to fig. 1 to 2, a method for improving edge warpage of a silicon wafer is characterized in that the following grinding steps are sequentially performed on a sliced silicon wafer:
grinding the edge of a silicon wafer by using a chamfering grinding wheel, and grinding the diameter of a primary chamfer, wherein the grinding amount of the diameter of the primary chamfer is A, and A is 230-270 mu m;
step two, carrying out primary double-sided grinding through a wide grinding wheel, wherein the removal amount of the width of the primary double-sided grinding is B, and the B is 28-32 mu m;
grinding the edge of the silicon wafer by using a chamfering grinding wheel, and grinding the diameter of the secondary chamfer, wherein the grinding amount of the diameter of the secondary chamfer is C, and C is 730-770 μm;
step four, carrying out secondary double-sided grinding through a wide grinding wheel, wherein the removal amount of the width of the secondary double-sided grinding is D, and D is 33-37 mu m;
A+C＝1000μm,B+D＝65μm。
after the grinding step is adopted, the problem of width caused by warping of the edge of the silicon wafer is effectively solved. The width is confirmed by adopting different grinding modes, the improvement effect of the range on the edge warping is most obvious, and the width difference of the positions of the cut-in point and the cut-out point can be within 100 um.
Preferably, A is 250 μm, B is 30 μm, C is 750 μm and D is 25 μm.
A was 230 μm, B was 28 μm, C was 770 μm, and D was 27 μm.
A is 270 μm, B is 32 μm, C is 730 μm, and D is 22 μm.
The cutting fluid used in the first step is pure water.
The grinding liquid used in the second step comprises 40Kg of grinding powder, 4.2L of P-37 and 70L of water, the granularity of the grinding powder is 7.5um, more than 99 percent of the grinding powder is Al2O3. The grind powder may be selected as FO # 1000.
And the cutting fluid used in the third step is pure water.
The grinding liquid used in the fourth step comprises 40Kg of grinding powder, 4.2L of P-37 and 70L of water, the granularity of the grinding powder is 7.5um, more than 99 percent of the grinding powder is Al2O3. The grind powder may be selected as FO # 1000.
Further preferably, the outer edge of the silicon wafer comprises an arc-shaped outer peripheral area and a linear flat edge area which are sequentially connected;
in the first step, when the arc-shaped peripheral area is ground, the autorotation speed of the silicon wafer is 19mm/s, and when the linear flat edge area is ground, the translation speed of the silicon wafer is 9 mm/s. The rotation speed of the grinding head is 4000 rpm/min.
In the second step, the rotating speed of the upper grinding fixed disc is 11rpm/min, the rotating speed of the lower fixed disc is 33rpm/min, and the time is 4-4.3 min;
in the third step, when the arc-shaped peripheral area is ground, the autorotation speed of the silicon wafer is 20mm/s, and when the linear flat edge area is ground, the translation speed of the silicon wafer is 10 mm/s. The rotation speed of the polishing head was 4500 rpm/min.
In the fourth step, the rotating speed of the upper grinding fixed disc is 11rpm/min, the rotating speed of the lower fixed disc is 33rpm/min, and the time is 4.5-5 min.
The following table is a table of the results of the difference in width of the edge warp points after different grinding parameters were used.
Further preferably, after grinding, a chamfer profilometer is used for measuring the size parameters of the silicon wafer, wherein the size parameters of the silicon wafer comprise the width of a chamfer on the silicon wafer, the width of a lower chamfer on the silicon wafer, the chamfer angle under the silicon wafer and the thickness of the silicon wafer.
X1 is the width of the upper chamfer of the silicon wafer, X2 is the width of the lower chamfer of the silicon wafer, theta 1 is the angle of the upper chamfer of the silicon wafer, theta 2 is the angle of the lower chamfer of the silicon wafer, and T1 is the thickness of the silicon wafer. And R is the radius of the front end of the silicon wafer.
| θ1 | θ2 | X1 | X2 | R | Y1 | Y2 | T | |
| Grinding amount of primary chamfer diameter | 10.9 | 11.6 | 551 | 541 | 170 | 263 | 261 | 524 |
| Amount of removal by primary grinding | 10.9 | 11.6 | 505 | 495 | 170 | 248 | 246 | 494 |
| Secondary chamfer diameter grinding amount | 10.9 | 11.6 | 505 | 495 | 170 | 248 | 246 | 494 |
| Amount of secondary grinding removal | 10.9 | 11.6 | 448 | 430 | 170 | 230 | 228 | 458 |
The warping condition of the edge of the ground silicon wafer can be known conveniently, and the selective inspection of the silicon wafer can be realized.
Further preferably, the wide grinding wheel is a ceramic disc. The main component of the alloy is Al2O3And the purity is more than 99%. The problem of heavy metal Fe pollution caused by the traditional cast iron disc is avoided. The heavy metal impurity Fe can cause the most serious heavy metal pollution to the silicon wafer, the potential barrier formed by dislocation of oxidation induced stacking fault is reduced, the device failure can be seriously influenced, and the yield of the chip is greatly reduced.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.
Claims (10)
1. A method for improving the edge warping of a silicon wafer is characterized in that the following grinding steps are sequentially carried out on the sliced silicon wafer:
grinding the edge of a silicon wafer by using a chamfering grinding wheel, and grinding the diameter of a primary chamfer, wherein the grinding amount of the diameter of the primary chamfer is A, and A is 230-270 mu m;
step two, carrying out primary double-sided grinding through a wide grinding wheel, wherein the removal amount of the width of the primary double-sided grinding is B, and the B is 28-32 mu m;
grinding the edge of the silicon wafer by using a chamfering grinding wheel, and grinding the diameter of the secondary chamfer, wherein the grinding amount of the diameter of the secondary chamfer is C, and C is 730-770 μm;
step four, carrying out secondary double-sided grinding through a wide grinding wheel, wherein the removal amount of the width of the secondary double-sided grinding is D, and D is 33-37 mu m;
A+C＝1000μm,B+D＝65μm。
2. the method for improving the edge warping of the silicon wafer as claimed in claim 1, wherein: a was 250 μm, B was 30 μm, C was 750 μm, and D was 25 μm.
3. The method for improving the edge warping of the silicon wafer as claimed in claim 1, wherein: a was 230 μm, B was 28 μm, C was 770 μm, and D was 27 μm.
4. The method for improving the edge warping of the silicon wafer as claimed in claim 1, wherein: a is 270 μm, B is 32 μm, C is 730 μm, and D is 22 μm.
5. The method for improving the edge warping of the silicon wafer as claimed in claim 1, wherein: after grinding, a chamfer profilometer is adopted to measure the size parameters of the silicon wafer, wherein the size parameters of the silicon wafer comprise the width of a chamfer on the silicon wafer, the width of a lower chamfer on the silicon wafer, the chamfer angle on the silicon wafer, the lower chamfer angle on the silicon wafer and the thickness of the silicon wafer.
6. The method for improving the edge warping of the silicon wafer as claimed in claim 1, wherein: the cutting fluid used in the first step is pure water.
7. The method for improving the edge warping of the silicon wafer as claimed in claim 1, wherein: the grinding liquid used in the second step comprises 40Kg of grinding powder, 4.2L of P-37 and 70L of water, the granularity of the grinding powder is 7.5um, more than 99 percent of the grinding powder is Al2O3。
8. The method for improving the edge warping of the silicon wafer as claimed in claim 1, wherein: and the cutting fluid used in the third step is pure water.
9. The method for improving the edge warping of the silicon wafer as claimed in claim 1, wherein: the grinding liquid used in the fourth step comprises 40Kg of grinding powder, 4.2L of P-37 and 70L of water, the granularity of the grinding powder is 7.5um, more than 99 percent of the grinding powder is Al2O3。
10. The method for improving the edge warping of the silicon wafer as claimed in claim 1, wherein: the outer edge of the silicon wafer comprises an arc-shaped peripheral area and a linear flat edge area which are sequentially connected;
in the first step, when the arc-shaped peripheral area is ground, the autorotation speed of the silicon wafer is 19mm/s, when the linear flat edge area is ground, the translation speed of the silicon wafer is 9mm/s, and the autorotation speed of the grinding head is 4000 rpm/min. (ii) a
In the second step, the rotating speed of the upper grinding fixed disc is 11rpm/min, the rotating speed of the lower fixed disc is 33rpm/min, and the time is 4-4.3 min;
in the third step, when the arc-shaped peripheral area is ground, the rotation speed of the silicon wafer is 20mm/s, when the linear flat edge area is ground, the translation speed of the silicon wafer is 10mm/s, and the rotation speed of the grinding head is 4500 rpm/min;
in the fourth step, the rotating speed of the upper grinding fixed disc is 11rpm/min, the rotating speed of the lower fixed disc is 33rpm/min, and the time is 4.5-5 min.
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| US5914053A (en) * | 1995-11-27 | 1999-06-22 | Shin-Etsu Handotai Co., Ltd. | Apparatus and method for double-sided polishing semiconductor wafers |
| CN102468135A (en) * | 2010-11-18 | 2012-05-23 | 北大方正集团有限公司 | Chip planarization process |
| CN105856074A (en) * | 2016-05-30 | 2016-08-17 | 深圳汇准科技有限公司 | Intelligent grinding fluid feeding system |
| CN106914802A (en) * | 2015-12-25 | 2017-07-04 | 有研半导体材料有限公司 | A kind of method for improving back of the body envelope silicon chip edge quality |
| CN107851569A (en) * | 2015-08-07 | 2018-03-27 | 信越半导体株式会社 | The manufacture method of semiconductor crystal wafer |
| CN109141324A (en) * | 2018-08-30 | 2019-01-04 | 杭州中芯晶圆半导体股份有限公司 | A kind of method of precise measurement silicon wafer top and bottom removal amount |
| CN109285762A (en) * | 2018-09-29 | 2019-01-29 | 中国电子科技集团公司第四十六研究所 | A kind of epitaxy of gallium nitride silicon chip edge processing technology |
| CN109509701A (en) * | 2018-11-02 | 2019-03-22 | 武汉电信器件有限公司 | A kind of abrasive polishing method and corresponding wafer of wafer |
| CN110625835A (en) * | 2019-09-12 | 2019-12-31 | 西安奕斯伟硅片技术有限公司 | Silicon wafer forming processing method |
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2020
- 2020-07-20 CN CN202010698929.1A patent/CN111872780B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5914053A (en) * | 1995-11-27 | 1999-06-22 | Shin-Etsu Handotai Co., Ltd. | Apparatus and method for double-sided polishing semiconductor wafers |
| CN102468135A (en) * | 2010-11-18 | 2012-05-23 | 北大方正集团有限公司 | Chip planarization process |
| CN107851569A (en) * | 2015-08-07 | 2018-03-27 | 信越半导体株式会社 | The manufacture method of semiconductor crystal wafer |
| CN106914802A (en) * | 2015-12-25 | 2017-07-04 | 有研半导体材料有限公司 | A kind of method for improving back of the body envelope silicon chip edge quality |
| CN105856074A (en) * | 2016-05-30 | 2016-08-17 | 深圳汇准科技有限公司 | Intelligent grinding fluid feeding system |
| CN109141324A (en) * | 2018-08-30 | 2019-01-04 | 杭州中芯晶圆半导体股份有限公司 | A kind of method of precise measurement silicon wafer top and bottom removal amount |
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| CN110625835A (en) * | 2019-09-12 | 2019-12-31 | 西安奕斯伟硅片技术有限公司 | Silicon wafer forming processing method |
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