DETAILED ACTION
This is the final office action for 18/703,269, filed 4/19/2024, which is a national stage entry of PCT/CN2021/131384, filed 11/18/2021, which claims priority to Chinese application CN202111219995.7, filed 10/20/2021.
Claims 1-9 and 11-16 are pending, and are considered herein.
In light of the claim amendments, the rejections under 35 U.S.C. 112(b) are withdrawn, and the prior art rejections are withdrawn. New grounds of rejection are presented herein.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Additional Prior Art
The Examiner wishes to apprise the Applicant of the following references, which are not currently applied in a rejection.
Ricci, et al. (ECS Journal of Solid State Science and Technology, 2021, 10, 025004): This reference teaches light-induced plating of aluminum contacts for a solar cell.
Tao, et al. (U.S. Patent Application Publication 2019/0067498 A1): This reference teaches light-induced plating of aluminum contacts for a solar cell.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1 and 7-8 are rejected under 35 U.S.C. 103 as being unpatentable over CN109524480A (provided in the IDS, with reference made to the provided machine translation), in view of Yao, et al. (Solar Energy Materials and Solar Cells, 2012, 96, 257-265) and Baker-O’Neal, et al. (U.S. Patent Application Publication 2015/0325716 A1).
In reference to Claim 1, CN109524480A teaches a method for preparing a solar cell (pages 2-3 of the provided machine translation). The solar cell is shown in Fig. 1.
The method of CN109524480A comprises a step of providing a tunneling layer on the front side of a p-type silicon wafer and an intrinsic polycrystalline silicon layer on top of the tunneling layer (step (2), page 2 of the machine translation).
The method of CN109524480A further comprises a step of locally forming N-doped polysilicon regions by masking and doping local regions of the polysilicon layer, then removing the remaining undoped polysilicon layer on the surface (step (3), page 2 of the machine translation).
This disclosure teaches the limitations of Claim 1, wherein the method comprises a first step of locally forming a tunnel silicon oxide layer and an N-type doped polysilicon layer on a front surface of a P-type silicon substrate, wherein the N-type doped polysilicon layer is stacked on the tunnel silicon oxide layer.
CN109524480A does not teach that the method comprises the second step of Claim 1.
However, CN109524480A teaches that front silver electrodes are prepared, aligned with the tunnel oxide and polysilicon emitter structure on the front side of the device (step (7), page 2 of the machine translation).
To solve the same problem of providing a p-type silicon solar cell with front contacts, Yao teaches a method of forming Ni contacts on the front surface of a solar cell, wherein the method includes light induced plating of Ni front electrodes on an n-type emitter, wherein the front electrodes have the same width as the openings in a surface insulating layer (Figs. 1-2, sections 3.1 and 3.2).
Yao teaches that the method of his invention provides the benefit of decreased costs, relative to solar cells that use silver front electrodes, as in CN109524480A (column 1, page 257).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have formed the front contact structures of CN109524480A via the method of Yao, because Yao teaches that the method of his invention provides the benefit of decreased costs, relative to solar cells that use silver front electrodes, as in CN109524480A (Yao, column 1, page 257).
Forming the front contact structures of CN109524480A via the method of Yao teaches the limitations of Claim 1, wherein the method comprises a second step of immersing the P-type silicon substrate having the tunnel silicon oxide layer and the N-type doped polysilicon layer locally formed on the front surface into an electroplating solution (Yao, Fig. 3, section 3.2), irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a front metal electrode on the front surface of the P-type silicon substrate, and wherein the front metal electrode is grown directly on the N-type doped polysilicon layer without depositing a metal seed layer on the N-type doped polysilicon layer (Yao, Fig. 3, section 3.2).
Forming the front contact structures of CN109524480A via the method of Yao teaches the limitations of Claim 1, wherein the width of the front metal electrode is the same as the width of the N-type doped polysilicon layer (i.e. the width of the opening in the front surface insulating layer, per Fig. 1 of Yao).
Modified CN109524480A does not teach a step of removing, by etching, a metal deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated nickel electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess nickel is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated nickel from the surface of the solar cell of modified CN109524480A by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claim 1, wherein the method comprises a step of removing, by etching, a metal deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
In reference to Claim 7, modified CN109524480A/Yao teaches that the second step comprises immersing the P-type silicon substrate having the tunnel silicon oxide layer and the N-type doped polysilicon layer locally formed on the front surface into an electroplating solution containing copper ions or silver ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal copper electrode or metal silver electrode on the N-type doped polysilicon layer on the front surface of the P-type silicon substrate (i.e. indirectly thereon, Fig. 2, section 3.2).
Modified CN109524480A does not teach a step of removing, by etching, a metal copper or silver deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess metal is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated copper or silver from the surface of the solar cell of modified CN109524480A by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claim 7, wherein the method comprises a step of removing, by etching, a metal copper or silver deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
In reference to Claim 8, modified CN109524480A/Yao teaches that the second step comprises immersing the P-type silicon substrate having the tunnel silicon oxide layer and the N-type doped polysilicon layer locally formed on the front surface into an electroplating solution containing nickel ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal nickel electrode on the N-type doped polysilicon layer on the front surface of the P-type silicon substrate (Fig. 2, section 3.2).
As described in the rejection of Claim 1 above, modified CN109524480A teaches that the second step includes removing, by etching, the metal nickel deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
Modified CN109524480A/Yao teaches that the second step comprises immersing the P-type silicon substrate having the metal nickel electrode into an electroplating solution containing copper ions or silver ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal copper electrode or metal silver electrode on the metal nickel electrode on the front surface of the P-type silicon substrate (Fig. 2, section 3.2).
Modified CN109524480A does not teach a step of removing, by etching, a metal copper or silver deposited on a region of the front surface of the P-type silicon substrate not covered by the metal nickel electrode.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess metal is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated copper or silver from the surface of the solar cell of modified CN109524480A by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claim 8, wherein the method comprises a step of removing, by etching, a metal copper or silver deposited on a region of the front surface of the P-type silicon substrate not covered by the metal nickel electrode.
Claims 2-4 are rejected under 35 U.S.C. 103 as being unpatentable over CN109524480A (provided in the IDS, with reference made to the provided machine translation), in view of Yao, et al. (Solar Energy Materials and Solar Cells, 2012, 96, 257-265) and Baker-O’Neal, et al. (U.S. Patent Application Publication 2015/0325716 A1), and further in view of Ha, et al. (U.S. Patent Application Publication 2019/0148573 A1).
In reference to Claim 2, CN109524480A teaches that the first step comprises: growing an entire tunnel silicon oxide layer on the front surface of the P-type silicon substrate (step (2) page 2 of the machine translation).
CN109524480A does not teach that the method includes the remaining steps of Claim 2.
To solve the same problem of patterning a tunneling layer and a doped silicon layer on a silicon substrate, Ha teaches a method in which a tunneling layer 160 and a doped silicon layer 170 are deposited over the entire surface of a solar cell, then patterned by applying a mask 202, etching away the unwanted regions of the tunnel layer 160 and the doped silicon layer 170 using an alkali solution, then removing the mask 202 by etching (Figs. 13B-F, paragraphs [0251], [0295]-[0322]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have patterned the selective contacts of the device of CN109524480A using the method of Ha, because Ha teaches that the method of his invention is a suitable and conventional method for patterning a contact region of a solar cell comprising a doped silicon layer and an underlying tunnel oxide layer.
Patterning the selective contacts of the device of CN109524480A using the method of Ha teaches the limitations of Claim 2, wherein the method includes forming an entire N-type doped polysilicon layer on the entire tunnel silicon oxide layer grown on the front surface; arranging a patterned mask on the entire N-type doped polysilicon layer; removing the N-type doped polysilicon layer in a region not covered by the mask using an alkali solution (Ha, paragraph [0315]); and removing the tunnel silicon oxide layer in a region not covered by the patterned mask, and then removing the patterned mask using an acid solution (Ha, paragraph [0322]).
Patterning the selective contacts of the device of CN109524480A using the method of Ha teaches the limitations of Claim 3, wherein the patterned mask includes an SiNx film (Ha, paragraph [0310]).
In reference to Claim 4, CN109524480A teaches that the width of the contact region is less than 50 microns (section (7), page 2 of the machine translation).
Therefore, modified CN109524480A teaches that the widths of the tunnel silicon oxide layer and the N-type doped polysilicon layer are each 5-50 μm (i.e. because the front contacts are taught to have the same/nearly the same width as the contact fingers, as described in the rejection of Claim 1 above).
In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See MPEP 2144.05 I. In the instant case, the claimed range of 5-50 μm lies within the taught range of less than 50 μm.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over CN109524480A (provided in the IDS, with reference made to the provided machine translation), in view of Yao, et al. (Solar Energy Materials and Solar Cells, 2012, 96, 257-265) and Baker-O’Neal, et al. (U.S. Patent Application Publication 2015/0325716 A1), and further in view of Mette, et al. (2006 IEEE 4th World Conference on Photovoltaic Energy Conference, Waikoloa, HI, USA, 2006, pp. 1056-1059).
In reference to Claim 9, modified CN109524480A/Yao teaches that the second step comprises immersing the P-type silicon substrate having the tunnel silicon oxide layer and the N-type doped polysilicon layer locally formed on the front surface into an electroplating solution containing nickel ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal nickel electrode on the N-type doped polysilicon layer on the front surface of the P-type silicon substrate (Fig. 2, section 3.2).
As described in the rejection of Claim 1 above, modified CN109524480A teaches that the second step includes removing, by etching, the metal nickel deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
Modified CN109524480A/Yao teaches that the second step comprises immersing the P-type silicon substrate having the metal nickel electrode into an electroplating solution containing copper ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal copper electrode on the metal nickel electrode on the front surface of the P-type silicon substrate (Fig. 2, section 3.2).
Modified CN109524480A does not teach a step of removing, by etching, a metal copper deposited on a region of the front surface of the P-type silicon substrate not covered by the metal nickel electrode.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess metal is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated copper from the surface of the solar cell of modified CN109524480A by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claim 9, wherein the method comprises a step of removing, by etching, a metal copper deposited on a region of the front surface of the P-type silicon substrate not covered by the metal nickel electrode.
Modified CN109524480A does not teach that the method of his invention comprises a step of immersing the P-type silicon substrate having the metal nickel electrode and the metal copper electrode stacked into an electroplating solution containing silver ions, and irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal silver electrode on the metal copper electrode and removing the metal silver remaining on the P-type silicon substrate by etching.
To solve the same problem of performing light-induced plating on the front surface of a p-type silicon solar cell, Mette teaches a method of light-induced plating of a layer of silver on the front contacts of a solar cell (Fig. 1, described in the “principle of light induced plating” section on ages 1056-1057).
Mette further teaches that the method of his invention provides the benefit of improving the aspect ratio (and therefore decrease the resistance) of existing metal contacts (Mette, “Introduction” section, column 1, page 1056).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have performed the electrode deposition process of modified CN109524480A to include sequential light-induced deposition of a layer of silver over the layers of nickel and copper, as taught by Mette, because Mette teaches that using light-induced plating to deposit a layer of silver over an existing front electrode provides the benefit of improving the aspect ratio (and therefore decrease the resistance) of existing metal contacts (Mette, “Introduction” section, column 1, page 1056).
Performing the electrode deposition process of modified CN109524480A to include sequential light-induced deposition of a layer of silver over the layers of nickel and copper, as taught by Mette, teaches the limitations of Claims 9 and 15-16, wherein the method comprises immersing the P-type silicon substrate having the metal nickel electrode and the metal copper electrode stacked into an electroplating solution containing silver ions, and irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal silver electrode on the metal copper electrode.
Modified CN109524480A does not teach a step of removing, by etching, a metal silver deposited on a region of the front surface of the P-type silicon substrate not covered by the metal copper electrode.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess metal is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated silver from the surface of the solar cell of modified CN109524480A by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claim 9, wherein the method comprises a step of removing, by etching, a metal silver deposited on a region of the front surface of the P-type silicon substrate not covered by the metal copper electrode.
Claims 1, 5-8, and 11-14 are rejected under 35 U.S.C. 103 as being unpatentable over Hallam, et al. (U.S. Patent Application Publication 2019/0157494 A1), in view of CN109524480A (provided in the IDS, with reference made to the provided machine translation), Yao, et al. (Solar Energy Materials and Solar Cells, 2012, 96, 257-265), and Baker-O’Neal, et al. (U.S. Patent Application Publication 2015/0325716 A1).
In reference to Claim 1, Hallam teaches a method for preparing a solar cell (Fig. 8, paragraphs [0130]-[0136]).
The method of Hallam comprise a step of forming a tunnel silicon oxide layer 804 (Fig. 8E, paragraph [0135]) and an N-type doped polysilicon layer 810A (Figs. 8F-8I, paragraph [0136]) on a front surface of a p-type (paragraph [0131]) silicon solar cell.
Hallam does not teach that the passivated contacts are “locally formed.”
To solve the same problem of providing a p-type silicon substrate with a front emitter layer and a front tunnel oxide layer, CN109524480A teaches that forming metallized front emitter contacts comprising a stack of tunnel oxide and doped polysilicon to have a localized structure (i.e. in which the passivated emitter is limited to the region of the metal contacts, as shown in Fig. 1 of CN109524480A), provides the benefit of both ensuring Ohmic contact between the metal electrode and the underlying silicon, while simultaneously eliminating front surface recombination (paragraph 1, “summary of the invention” section, page 1 of the machine translation).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have formed the doped polysilicon layer 810A and the underlying front tunneling layer 804 to have a localized structure (i.e. limited to the dimensions of the front electrode), based on CN109524480A’s disclosure of the benefits of such a structure.
This modification teaches the limitations of Claim 1, wherein the passivated contacts are “locally formed.”
Hallam does not teach that the method comprises the second step of Claim 1.
However, he teaches that the front electrodes 812 of his invention are formed by plating (paragraph [0136]), and that the electrodes of his invention may suitably comprise nickel/copper stacks (paragraph [0096])
To solve the same problem of providing a p-type silicon solar cell with front contacts comprising nickel/copper stacks, Yao teaches a method of forming Ni contacts on the front surface of a solar cell, wherein the method includes light induced plating of Ni front electrodes on an n-type emitter, wherein the front electrodes have the same width as the openings in a surface insulating layer (Figs. 1-2, sections 3.1 and 3.2).
Yao teaches that the method of his invention provides the benefit of decreased costs (column 1, page 257).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have formed the front contact structures of Hallam via the method of Yao, because Yao teaches that the method of his invention provides the benefit of decreased costs, and is a suitable method to form a nickel/copper stack electrode, like the electrodes of Hallam (Yao, column 1, page 257).
Forming the front contact structures of Hallam via the method of Yao teaches the limitations of Claim 1, wherein the method comprises a second step of immersing the P-type silicon substrate having the tunnel silicon oxide layer and the N-type doped polysilicon layer locally formed on the front surface into an electroplating solution (Yao, Fig. 3, section 3.2), irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a front metal electrode on the front surface of the P-type silicon substrate, and wherein the front metal electrode is grown directly on the N-type doped polysilicon layer without depositing a metal seed layer on the N-type doped polysilicon layer (Yao, Fig. 3, section 3.2).
Forming the front contact structures of Hallam via the method of Yao teaches the limitations of Claim 1, wherein the width of the front metal electrode is the same as the width of the N-type doped polysilicon layer (i.e. the width of the opening in the front surface insulating layer, per Fig. 1 of Yao).
Modified Hallam does not teach a step of removing, by etching, a metal deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated nickel electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess nickel is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated nickel from the surface of the solar cell of modified Hallam by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claim 1, wherein the method comprises a step of removing, by etching, a metal deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
In reference to Claim 5, Hallam teaches that, before the second step (i.e. before, the step in which the front electrodes are formed in the method of his invention), the method further comprises forming a P+-type doped layer on the back surface of the P-type silicon substrate (steps 8G-8H, paragraph [0186]).
It is the Examiner’s position that, because Claim 5 does not recite a specific concentration for the P+-type layer, Hallam’s disclosure teaches the limitations of Claim 5.
In reference to Claim 6, Hallam teaches that, before the second step (i.e. before, the step in which the front electrodes are formed in the method of his invention), the method further comprises: sequentially forming the/a tunnel silicon oxide layer 804 (Fig. 8E, paragraph [0135]) and a P-type doped polysilicon layer 810B (Figs. 8F-8I, paragraph [0136]) on the back surface of the P-type silicon substrate 800.
In reference to Claims 7 and 11-12, modified Hallam/Yao teaches that the second step comprises immersing the P-type silicon substrate having the tunnel silicon oxide layer and the N-type doped polysilicon layer locally formed on the front surface into an electroplating solution containing copper ions or silver ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal copper electrode or metal silver electrode on the N-type doped polysilicon layer on the front surface of the P-type silicon substrate (i.e. indirectly thereon, Fig. 2, section 3.2).
Modified Hallam does not teach a step of removing, by etching, a metal copper or silver deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess metal is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated copper or silver from the surface of the solar cell of modified Hallam by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claims 7 and 11-12, wherein the method comprises a step of removing, by etching, a metal copper or silver deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
In reference to Claims 8 and 13-14, modified Hallam/Yao teaches that the second step comprises immersing the P-type silicon substrate having the tunnel silicon oxide layer and the N-type doped polysilicon layer locally formed on the front surface into an electroplating solution containing nickel ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal nickel electrode on the N-type doped polysilicon layer on the front surface of the P-type silicon substrate (Fig. 2, section 3.2).
As described in the rejection of Claim 1 above, modified Hallam teaches that the second step includes removing, by etching, the metal nickel deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
Modified Hallam/Yao teaches that the second step comprises immersing the P-type silicon substrate having the metal nickel electrode into an electroplating solution containing copper ions or silver ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal copper electrode or metal silver electrode on the metal nickel electrode on the front surface of the P-type silicon substrate (Fig. 2, section 3.2).
Modified Hallam does not teach a step of removing, by etching, a metal copper or silver deposited on a region of the front surface of the P-type silicon substrate not covered by the metal nickel electrode.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess metal is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated copper or silver from the surface of the solar cell of modified Hallam by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claims 8 and 13-14, wherein the method comprises a step of removing, by etching, a metal copper or silver deposited on a region of the front surface of the P-type silicon substrate not covered by the metal nickel electrode.
Claims 2-4 are rejected under 35 U.S.C. 103 as being unpatentable over Hallam, et al. (U.S. Patent Application Publication 2019/0157494 A1), in view of CN109524480A (provided in the IDS, with reference made to the provided machine translation), Yao, et al. (Solar Energy Materials and Solar Cells, 2012, 96, 257-265), and Baker-O’Neal, et al. (U.S. Patent Application Publication 2015/0325716 A1), and further in view of Ha, et al. (U.S. Patent Application Publication 2019/0148573 A1).
In reference to Claim 2, modified Hallam does not teach the limitations of Claim 2.
To solve the same problem of patterning a tunneling layer and a doped silicon layer on a silicon substrate, Ha teaches a method in which a tunneling layer 160 and a doped silicon layer 170 are deposited over the entire surface of a solar cell, then patterned by applying a mask 202, etching away the unwanted regions of the tunnel layer 160 and the doped silicon layer 170 using an alkali solution, then removing the mask 202 by etching (Figs. 13B-F, paragraphs [0251], [0295]-[0322]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have patterned the selective contacts of the device of modified Hallam using the method of Ha, because Ha teaches that the method of his invention is a suitable and conventional method for patterning a contact region of a solar cell comprising a doped silicon layer and an underlying tunnel oxide layer.
Patterning the selective contacts of the device of modified Hallam using the method of Ha teaches the limitations of Claim 2, wherein the first step includes forming an entire N-type doped polysilicon layer on the entire tunnel silicon oxide layer grown on the front surface; arranging a patterned mask on the entire N-type doped polysilicon layer; removing the N-type doped polysilicon layer in a region not covered by the mask using an alkali solution (Ha, paragraph [0315]); and removing the tunnel silicon oxide layer in a region not covered by the patterned mask, and then removing the patterned mask using an acid solution (Ha, paragraph [0322]).
Patterning the selective contacts of the device of CN109524480A using the method of Ha teaches the limitations of Claim 3, wherein the patterned mask includes an SiNx film (Ha, paragraph [0310]).
In reference to Claim 4, CN109524480A teaches that the width of the contact region is less than 50 microns (section (7), page 2 of the machine translation).
Therefore, modified Hallam teaches that the widths of the tunnel silicon oxide layer and the N-type doped polysilicon layer are each 5-50 μm (i.e. because the front contacts are taught to have the same/nearly the same width as the contact fingers, as described in the rejection of Claim 1 above).
In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See MPEP 2144.05 I. In the instant case, the claimed range of 5-50 μm lies within the taught range of less than 50 μm.
Claims 9 and 15-16 are rejected under 35 U.S.C. 103 as being unpatentable over Hallam, et al. (U.S. Patent Application Publication 2019/0157494 A1), in view of CN109524480A (provided in the IDS, with reference made to the provided machine translation), Yao, et al. (Solar Energy Materials and Solar Cells, 2012, 96, 257-265), and Baker-O’Neal, et al. (U.S. Patent Application Publication 2015/0325716 A1), and further in view of Mette, et al. (2006 IEEE 4th World Conference on Photovoltaic Energy Conference, Waikoloa, HI, USA, 2006, pp. 1056-1059).
In reference to Claims 9 and 15-16, modified Hallam/Yao teaches that the second step comprises immersing the P-type silicon substrate having the tunnel silicon oxide layer and the N-type doped polysilicon layer locally formed on the front surface into an electroplating solution containing nickel ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal nickel electrode on the N-type doped polysilicon layer on the front surface of the P-type silicon substrate (Fig. 2, section 3.2).
As described in the rejection of Claim 1 above, modified Hallam teaches that the second step includes removing, by etching, the metal nickel deposited on a region of the front surface of the P-type silicon substrate not covered by the N-type doped polysilicon layer.
Modified Hallam/Yao teaches that the second step comprises immersing the P-type silicon substrate having the metal nickel electrode into an electroplating solution containing copper ions, irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal copper electrode on the metal nickel electrode on the front surface of the P-type silicon substrate (Fig. 2, section 3.2).
Modified Hallam does not teach a step of removing, by etching, a metal copper deposited on a region of the front surface of the P-type silicon substrate not covered by the metal nickel electrode.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess metal is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated copper from the surface of the solar cell of modified Hallam by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claims 9 and 15-16, wherein the method comprises a step of removing, by etching, a metal copper deposited on a region of the front surface of the P-type silicon substrate not covered by the metal nickel electrode.
Modified Hallam does not teach that the method of his invention comprises a step of immersing the P-type silicon substrate having the metal nickel electrode and the metal copper electrode stacked into an electroplating solution containing silver ions, and irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal silver electrode on the metal copper electrode and removing the metal silver remaining on the P-type silicon substrate by etching.
To solve the same problem of performing light-induced plating on the front surface of a p-type silicon solar cell, Mette teaches a method of light-induced plating of a layer of silver on the front contacts of a solar cell (Fig. 1, described in the “principle of light induced plating” section on ages 1056-1057).
Mette further teaches that the method of his invention provides the benefit of improving the aspect ratio (and therefore decrease the resistance) of existing metal contacts (Mette, “Introduction” section, column 1, page 1056).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have performed the electrode deposition process of modified Hallam to include sequential light-induced deposition of a layer of silver over the layers of nickel and copper, as taught by Mette, because Mette teaches that using light-induced plating to deposit a layer of silver over an existing front electrode provides the benefit of improving the aspect ratio (and therefore decrease the resistance) of existing metal contacts (Mette, “Introduction” section, column 1, page 1056).
Performing the electrode deposition process of modified Hallam to include sequential light-induced deposition of a layer of silver over the layers of nickel and copper, as taught by Mette, teaches the limitations of Claims 9 and 15-16, wherein the method comprises immersing the P-type silicon substrate having the metal nickel electrode and the metal copper electrode stacked into an electroplating solution containing silver ions, and irradiating the front surface of the P-type silicon substrate with light for a set duration so as to grow a metal silver electrode on the metal copper electrode.
Modified Hallam does not teach a step of removing, by etching, a metal silver deposited on a region of the front surface of the P-type silicon substrate not covered by the metal copper electrode.
To solve the same problem of providing a front metal electrode for a p-type silicon solar cell, Baker-O’Neal teaches that removing excess plated electrode material provides the benefit of positively influencing metal-silicon adhesion (paragraph [0028]).
Baker-O’Neal further teaches that this excess metal is removed by etching (paragraphs [0032] and [0037]).
Therefore, absent a showing of persuasive secondary considerations, it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have removed excess plated silver from the surface of the solar cell of modified Hallam by etching, based on the disclosure of Baker-O’Neal that such a removal provides the benefit of improving adhesion between the silicon and the metal electrode.
This modification teaches the limitations of Claims 9 and 15-16, wherein the method comprises a step of removing, by etching, a metal silver deposited on a region of the front surface of the P-type silicon substrate not covered by the metal copper electrode.
Response to Arguments
The Applicant’s arguments with respect to the prior art rejections and rejections under 35 U.S.C. 112(b) have been fully considered and are persuasive. Therefore, these rejections have been withdrawn. However, upon further consideration, new prior art rejections are made herein.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SADIE WHITE whose telephone number is (571)272-3245. The examiner can normally be reached 6am-2:30pm ET.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Allison Bourke, can be reached at 303-297-4684. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/SADIE WHITE/Primary Examiner, Art Unit 1721
Prosecution Insights