Title of Invention	AN ACID CORROSION SOLUTION FOR PREPARING POLYSILICON TEXTURE,
Abstract	An acid corrosion solution for preparing polysilicon suede is obtained by mixing an oxidant and a hydrogen fluoride. The oxidant is a nitrate or nitrite. The method applied of the solution includes putting the polysilicon cut pieces into the acid corrosion solution to carry out the corrosion reaction. The reaction time is about 30 seconds to 20 minutes and the temperature of acid corrosion solution is -10°C to 25°C.

Title of Invention

AN ACID CORROSION SOLUTION FOR PREPARING POLYSILICON TEXTURE,

Abstract

An acid corrosion solution for preparing polysilicon suede is obtained by mixing an oxidant and a hydrogen fluoride. The oxidant is a nitrate or nitrite. The method applied of the solution includes putting the polysilicon cut pieces into the acid corrosion solution to carry out the corrosion reaction. The reaction time is about 30 seconds to 20 minutes and the temperature of acid corrosion solution is -10°C to 25°C.

Full Text	FORM 2 THE PATENTS ACT 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See section 10 and rule 13) 1. ' AN ACID CORROSION SOLUTON FOR PREPARING POLYSILICON SUEDE AND THE APPLIED METHOD OF IT. * 2. 1. (A) WUXI SUNTECH POWER CO., LTD. (B) A Company incorporate under the laws of China (C) 17-6 Chang Jiang South Road, New District, Wuxi, Jiangsu 214028, China. 1 The following specification particularly describes the invention and the manner in which it is to be performed. The present invention relates to an acid corrosion solution for preparing polysilicon suede (texture) for solar cell and a method for preparing polysilicon texture for solar cell using the acid corrosion solution. Background of the invention The Chinese patent application with the application No, 200410064831.1 disclosed a method for preparing polysilicon texture, wherein the initial surface morphology of the polysilicon could be maintained by using acid corrosion solution instead of conventional NaOH and KOH corrosion solutions meanwhile the damage layer on the polysUicon surface produced during the cutting process was removed. Therefore, the required texture could be obtained On the polysilicon surface after removing the damage layer. Although this method can satisfy the requirement for mass-preparation of the polysilicon texture, its disadvantages are obvious such as high cost for dealing with The waste acid produced during th^ process, especially the severe pollution of the heavy metal in waste acid to the environment, since the oxidant in acid corrosion solution is Cr03) K2Cr207 or the mixture thereof. Summary of Invention It is therefore an aspect of the present invention is to provide an acid corrosion solution with the advantages of lower cost of dealing with the waste acid produced during the process and avoid the pollution of the heavy metal. Another aspect of the present invention is to provide a method for preparing the polysilicon texture by using the acid corrosion solution. That is, the present invention provides an acid corrosion solution for preparing the polysilicon texture by mixing oxidant and hydrofluoric acid solution, wherein the oxidant is nitrate or nitrite. Preferably, the nitrate is sodium nitrate, potassium nitrate or ammonium nitrate, the nitrite is sodium nitrite, potassium nitrite or ammonium nitrite. Preferably, the oxidant has a concentration of 0,1 to 10 mol/L and the hydrofluoric acid solution has a concentration of 10 to 25 mol/L. Preferably, the oxidant has a concentration of 0.3 to 5 mol/L and the hydrofluoric acid solution has a concentration of 15 to 22 mol/L. A method for preparing the polysilicon texture by using the acid corrosion % solution specially includes immerging the chipping polysilicon into the acid corrosion solution to perform the corrosion reaction for 30 sec to 20 min, the temperature of the acid corrosion solution is -10 °C to 25 'C, Preferably, the reaction temperature is 0°C to 15"C. Preferably, the reaction time is 1 min to 10 min. During the process of producing polysilicon texture by using the acid corrosion solution, the waste acid produced can be disposed via common neutralization reaction and the pollution of the heavy metal in the waste liquid can be avoided. The method for preparing the polysilicon texture by using the acid corrosion solution in the present invention is suitable for both intermittent and continuous mass processes. Brief Description of the Drawings FIG. 1 is SEM photograph of the corroded polysilicon texture in Example 1. FIG. 2 is SEM photograph of the corroded polysilicon texture in Example 2. FIG. 3 is SEM photograph of the corroded polysilicon texture in Example 3. Detail description of the Invention Example 1 5mol KN03 is added into hydrofluoric acid solution having a concentration of 20 mol/L and uniformly mixed and maintained at 20 °C, after that the polysilicon sheet with 125125 chipped by Linear-Cut is immerged in the solution and corroded for 10 min. Then the obtained polysilicon sheet is made into a solar cell. The solar cell has a conversion efficiency of 14.49%, fill factor of 0.765, open-circuit voltage of 598mV and short-circuit current of 4.95A. The surface morphology of the corroded polysilicon is illuminated in FIG. 1. Example 2 2.34moI NH4N02 is added into 1L hydrofluoric acid solution having a concentration of 20mol/L and uniformly mixed and maintained at -10"C, after that the polysilicon sheet with 125125 is immerged in the solution and corroded for 20 min. Then the obtained polysilicon sheet is made into a solar cell. The solar cell has a conversion efficiency of 15.38%S fill factor of 0,768, open-circuit voltage of 611mV and short-circuit current of 5.12A. The surface morphology of the corroded polysilicon is illuminated in FIG. 2, Example 3 1.17mol NaN03 is added into IL hydrofluoric acid solution having a concentration of 20mol/L and uniformly mixed and maintained at 10"C, and then adding 0,15mol !SfaN02, after that the polysilicon sheet with 125"' 125 is immerged in 1 the solution and corroded for 20 min. Then the obtained polysilicon sheet is made into a solar cell The solar cell has a conversion efficiency of 15.03%, fill factor of 0.771, open-circuit voltage of 608mV and short-circuit current of 5.01A. The surface morphology of the corroded polysilicon is illuminated inFIG. 3. The concentrations of oxidant and hydrofluoric acid of the acid corrosion solution in the present invention, the temperature of the solution and corrosion time during the preparing process of the polysilicon texture are not merely limited to the scope disclosed in the above examples. The parameters such as concentration, temperature, time etc. can be properly adjusted according to the present invention and the requirement for the performance of the polysilicon. For example, the corrosion time can be prolonged or shortened and the corrosion temperature can be increased or decreased according to the concentrations of the hydrofluoric acid solution and oxidant, in order to obtain the polysilicon having the required texture. As for the concentrations of the oxidant and hydrofluoric acid, the solution temperature and corrosion time, the concentration of hydrofluoric acid is 10 to 25 mol/L, especially 15 to 22 mol/L, the concentration of oxidant is 0.1 to 10 mol/L, especially 03 to 5 mol/L, the temperature of the solution is -10V to 25°C, especially 0°C to 15"C, corrosion time is 30 sec to 20 min, especially 1 min to 10 min. Under these conditions, the required corrosion efficiency and satisfied production efficiency can be achieved. ^ We Claim: 1. An acid corrosion solution for preparing polysilicon texture, comprising the mixed oxidant and hydrofluoric acid solution, wherein the oxidant is nitrate or nitrite. 2. The acid corrosion solution for preparing polysilicon texture according to claim 1, wherein the nitrate is sodium nitrate, potassium nitrate or ammonium nitrate, the nitrite is sodium nitrite, potassium nitrite or ammonium nitrite. 3. The acid corrosion solution for preparing polysilicon texture according to claim ls wherein the oxidant has a concentration of 0.1 to 10 mol/L and the hydrofluoric acid solution has a concentration of 10 to 25 mol/L. 4. The acid corrosion solution for preparing polysilicon texture according to claim 1, wherein the oxidant has a concentration of 0.3 to 5 mol/L and the hydrofluoric acid solution has a concentration of 15 to 22 mol/L. 5. A method for preparing polysilicon texture using the acid corrosion solution in any one of claim 1. 2 or 3, comprising: adjusting the temperature of the acid corrosion solution is -10 'C to 25 'C; and immerging the chipping polysilicon into the acid corrosion solution to perform the corrosion reaction for 30 sec to 20 min.. 6. The method for preparing polysilicon texture according to claim 4, wherein the reaction temperature is 0 °C to 15 °C. 7. The method for preparing polysilicon texture according to claim 4, wherein the reaction time is 1 min to 10 min. 8. An acid corrosion soluton for preparing polysilicon suede and the applied method of it as claimed substantially as herein described with forgoing description & drawings. Dated this 20th day of September 2008. Dr. Rajeshkumar H. Acharya Advocate & Patent Agent For and on Behalf of Applicant

Full Text

FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. ' AN ACID CORROSION SOLUTON FOR PREPARING POLYSILICON SUEDE AND THE APPLIED METHOD OF IT. *
2.
1. (A) WUXI SUNTECH POWER CO., LTD.
(B) A Company incorporate under the laws of China
(C) 17-6 Chang Jiang South Road, New District, Wuxi, Jiangsu 214028, China.
1
The following specification particularly describes the invention and the manner in which it is to be performed.

The present invention relates to an acid corrosion solution for preparing polysilicon suede (texture) for solar cell and a method for preparing polysilicon texture for solar cell using the acid corrosion solution.
Background of the invention
The Chinese patent application with the application No, 200410064831.1 disclosed a method for preparing polysilicon texture, wherein the initial surface morphology of the polysilicon could be maintained by using acid corrosion solution instead of conventional NaOH and KOH corrosion solutions meanwhile the damage layer on the polysUicon surface produced during the cutting process was removed. Therefore, the required texture could be obtained On the polysilicon surface after removing the damage layer. Although this method can satisfy the requirement for mass-preparation of the polysilicon texture, its disadvantages are obvious such as high cost for dealing with The waste acid produced during th^ process, especially the severe pollution of the heavy metal in waste acid to the environment, since the oxidant in acid corrosion solution is Cr03) K2Cr207 or the mixture thereof.
Summary of Invention
It is therefore an aspect of the present invention is to provide an acid corrosion solution with the advantages of lower cost of dealing with the waste acid produced during the process and avoid the pollution of the heavy metal. Another aspect of the present invention is to provide a method for preparing the polysilicon texture by using the acid corrosion solution.
That is, the present invention provides an acid corrosion solution for preparing the polysilicon texture by mixing oxidant and hydrofluoric acid solution, wherein the oxidant is nitrate or nitrite.
Preferably, the nitrate is sodium nitrate, potassium nitrate or ammonium nitrate, the nitrite is sodium nitrite, potassium nitrite or ammonium nitrite.
Preferably, the oxidant has a concentration of 0,1 to 10 mol/L and the hydrofluoric acid solution has a concentration of 10 to 25 mol/L.
Preferably, the oxidant has a concentration of 0.3 to 5 mol/L and the hydrofluoric acid solution has a concentration of 15 to 22 mol/L.
A method for preparing the polysilicon texture by using the acid corrosion
%

solution specially includes immerging the chipping polysilicon into the acid corrosion solution to perform the corrosion reaction for 30 sec to 20 min, the temperature of the acid corrosion solution is -10 °C to 25 'C,
Preferably, the reaction temperature is 0°C to 15"C.
Preferably, the reaction time is 1 min to 10 min.
During the process of producing polysilicon texture by using the acid corrosion solution, the waste acid produced can be disposed via common neutralization reaction and the pollution of the heavy metal in the waste liquid can be avoided. The method for preparing the polysilicon texture by using the acid corrosion solution in the present invention is suitable for both intermittent and continuous mass processes.
Brief Description of the Drawings
FIG. 1 is SEM photograph of the corroded polysilicon texture in Example 1. FIG. 2 is SEM photograph of the corroded polysilicon texture in Example 2. FIG. 3 is SEM photograph of the corroded polysilicon texture in Example 3.
Detail description of the Invention
Example 1
5mol KN03 is added into hydrofluoric acid solution having a concentration of 20 mol/L and uniformly mixed and maintained at 20 °C, after that the polysilicon sheet with 125*125 chipped by Linear-Cut is immerged in the solution and corroded for 10 min. Then the obtained polysilicon sheet is made into a solar cell. The solar cell has a conversion efficiency of 14.49%, fill factor of 0.765, open-circuit voltage of 598mV and short-circuit current of 4.95A. The surface morphology of the corroded polysilicon is illuminated in FIG. 1.
Example 2
2.34moI NH4N02 is added into 1L hydrofluoric acid solution having a concentration of 20mol/L and uniformly mixed and maintained at -10"C, after that the polysilicon sheet with 125*125 is immerged in the solution and corroded for 20 min. Then the obtained polysilicon sheet is made into a solar cell. The solar cell has a conversion efficiency of 15.38%S fill factor of 0,768, open-circuit voltage of 611mV and short-circuit current of 5.12A. The surface morphology of the corroded polysilicon is illuminated in FIG. 2,
Example 3
1.17mol NaN03 is added into IL hydrofluoric acid solution having a concentration of 20mol/L and uniformly mixed and maintained at 10"C, and then adding 0,15mol !SfaN02, after that the polysilicon sheet with 125"' 125 is immerged in
1

the solution and corroded for 20 min. Then the obtained polysilicon sheet is made into a solar cell The solar cell has a conversion efficiency of 15.03%, fill factor of 0.771, open-circuit voltage of 608mV and short-circuit current of 5.01A. The surface morphology of the corroded polysilicon is illuminated inFIG. 3.
The concentrations of oxidant and hydrofluoric acid of the acid corrosion solution in the present invention, the temperature of the solution and corrosion time during the preparing process of the polysilicon texture are not merely limited to the scope disclosed in the above examples. The parameters such as concentration, temperature, time etc. can be properly adjusted according to the present invention and the requirement for the performance of the polysilicon. For example, the corrosion time can be prolonged or shortened and the corrosion temperature can be increased or decreased according to the concentrations of the hydrofluoric acid solution and oxidant, in order to obtain the polysilicon having the required texture.
As for the concentrations of the oxidant and hydrofluoric acid, the solution temperature and corrosion time, the concentration of hydrofluoric acid is 10 to 25 mol/L, especially 15 to 22 mol/L, the concentration of oxidant is 0.1 to 10 mol/L, especially 03 to 5 mol/L, the temperature of the solution is -10V to 25°C, especially 0°C to 15"C, corrosion time is 30 sec to 20 min, especially 1 min to 10 min. Under these conditions, the required corrosion efficiency and satisfied production efficiency can be achieved.
^

We Claim:
1. An acid corrosion solution for preparing polysilicon texture, comprising the mixed oxidant and hydrofluoric acid solution, wherein the oxidant is nitrate or nitrite.
2. The acid corrosion solution for preparing polysilicon texture according to claim 1, wherein the nitrate is sodium nitrate, potassium nitrate or ammonium nitrate, the nitrite is sodium nitrite, potassium nitrite or ammonium nitrite.
3. The acid corrosion solution for preparing polysilicon texture according to claim ls wherein the oxidant has a concentration of 0.1 to 10 mol/L and the hydrofluoric acid solution has a concentration of 10 to 25 mol/L.
4. The acid corrosion solution for preparing polysilicon texture according to claim 1, wherein the oxidant has a concentration of 0.3 to 5 mol/L and the hydrofluoric acid solution has a concentration of 15 to 22 mol/L.
5. A method for preparing polysilicon texture using the acid corrosion solution in any one of claim 1. 2 or 3, comprising:
adjusting the temperature of the acid corrosion solution is -10 'C to 25 'C; and
immerging the chipping polysilicon into the acid corrosion solution to perform the corrosion reaction for 30 sec to 20 min..
6. The method for preparing polysilicon texture according to claim 4, wherein the reaction temperature is 0 °C to 15 °C.
7. The method for preparing polysilicon texture according to claim 4, wherein the reaction time is 1 min to 10 min.
8. An acid corrosion soluton for preparing polysilicon suede and the
applied method of it as claimed substantially as herein described with forgoing
description & drawings.
Dated this 20th day of September 2008.
Dr. Rajeshkumar H. Acharya
Advocate & Patent Agent
For and on Behalf of Applicant

Documents:

2032-MUMNP-2008-ABSTRACT(GRANTED)-(12-4-2012).pdf

2032-mumnp-2008-abstract.doc

2032-mumnp-2008-abstract.pdf

2032-MUMNP-2008-CANCELLED PAGES(12-12-2011).pdf

2032-MUMNP-2008-CLAIMS(AMENDED)-(12-12-2011).pdf

2032-MUMNP-2008-CLAIMS(AMENDED)-(8-8-2011).pdf

2032-MUMNP-2008-CLAIMS(GRANTED)-(12-4-2012).pdf

2032-MUMNP-2008-CLAIMS(MARKED COPY)-(12-12-2011).pdf

2032-mumnp-2008-claims.doc

2032-mumnp-2008-claims.pdf

2032-MUMNP-2008-CORRESPONDENCE(8-12-2008).pdf

2032-MUMNP-2008-CORRESPONDENCE(IPO)-(12-4-2012).pdf

2032-mumnp-2008-correspondence.pdf

2032-MUMNP-2008-DECLARATION(8-12-2008).pdf

2032-mumnp-2008-description(complete).doc

2032-mumnp-2008-description(complete).pdf

2032-MUMNP-2008-DESCRIPTION(GRANTED)-(12-4-2012).pdf

2032-MUMNP-2008-DRAWING(GRANTED)-(12-4-2012).pdf

2032-mumnp-2008-drawing.pdf

2032-MUMNP-2008-ENGLISH TRANSLATION(12-12-2011).pdf

2032-MUMNP-2008-ENGLISH TRANSLATION(8-8-2011).pdf

2032-MUMNP-2008-FORM 1(8-12-2008).pdf

2032-mumnp-2008-form 1.pdf

2032-mumnp-2008-form 18.pdf

2032-MUMNP-2008-FORM 2(GRANTED)-(12-4-2012).pdf

2032-MUMNP-2008-FORM 2(TITLE PAGE)-(GRANTED)-(12-4-2012).pdf

2032-mumnp-2008-form 2(title page).pdf

2032-mumnp-2008-form 2.doc

2032-mumnp-2008-form 2.pdf

2032-MUMNP-2008-FORM 26(8-12-2008).pdf

2032-MUMNP-2008-FORM 3(8-12-2008).pdf

2032-MUMNP-2008-FORM 3(8-8-2011).pdf

2032-mumnp-2008-form 3.pdf

2032-MUMNP-2008-FORM 5(8-12-2008).pdf

2032-mumnp-2008-form 5.pdf

2032-MUMNP-2008-OTHER DOCUMENT(8-8-2011).pdf

2032-mumnp-2008-pct-isa-210.pdf

2032-MUMNP-2008-REPLY TO EXAMINATION REPORT(12-12-2011).pdf

2032-MUMNP-2008-REPLY TO EXAMINATION REPORT(8-8-2011).pdf

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Patent Number

251871

Indian Patent Application Number

2032/MUMNP/2008

PG Journal Number

16/2012

Publication Date

20-Apr-2012

Grant Date

12-Apr-2012

Date of Filing

23-Sep-2008

Name of Patentee

WUXI SUNTECH POWER CO LTD

Applicant Address

17-6 CHANG JIANG SOUTH ROAD, NEW DISTRICT, WUXI, JIANGSU 214028,

Inventors:

#	Inventor's Name	Inventor's Address
1	JI JINGJIA	17-6 CHANG JIANG SOUTH ROAD, NEW DISTRICT, WUXI, JIANGSU 214028
2	QIN YUSEN	17-6 CHANGJIANG SOUTH ROAD, NEW DISTRICT, WUXI, JIANGSU 214028
3	SHI ZHENGRONG	17-6 CHANGJIANG SOUTH ROAD, NEW DISTRICT, WUXI, JIANGSU 214028

PCT International Classification Number

H01L21/306

PCT International Application Number

PCT/CN2006/001078

PCT International Filing date

2006-05-24

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	200610065676.4	2006-03-21	China