DETAILED ACTION
This is the final office action for 18/689/882, filed 3/7/2024, which is a national stage entry of PCT/CN2022/117237, filed 9/6/2022, which claims priority to Chinese application CN202111056381.1, filed 9/9/2021.
Claims 1 and 3-11 are pending; Claims 1 and 3-9 are considered herein.
In light of the claim amendments filed 11/19/2025, the rejections of record are withdrawn, and new grounds of rejection are presented herein.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 reference, which is not currently applied in a rejection.
Lipinski, et al., Phys. Stat. Sol. (c) 4, No. 4, 1566-1569 (2007): This reference teaches PECVD deposition of multilayered SiON layers.
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, 3, and 8-9 are rejected under 35 U.S.C. 103 as being unpatentable over Seiffe, et al. (J. Appl. Phys. 109, 034105 (2011)), in view of Hu, et al. (U.S. Patent Application Publication 2012/0167973 A1) and Brinkmann, et al. (Solar Energy Materials and Solar Cells 108 (2013) 180-188).
In reference to Claim 1, Seiffe teaches a method for manufacturing a backside passivation structure of a battery cell (section III A, columns 1-2, page 4).
The method of Seiffe comprises depositing a passivation layer (corresponding to the SiON layer) directly on a back surface of a silicon wafer (Fig. 1, column 1, page 4).
Seiffe teaches that the rear SiON passivation layer is deposited by a PECVD method in column 1, page 4.
The instant specification recognizes this method as the method of the instant invention (paragraphs [0029]-[0030]). In PECVD methods, the reactant gases are introduced into the plasma reaction chamber to produce the desired films.
Therefore, Seiffe teaches that the rear SiON passivation layer is formed through injecting a first reaction gas (i.e. SiH4, H2, and N2O) into a coating device (i.e. a PECVD coating device).
Seiffe teaches that the method of his invention comprises depositing an internal reflection layer (corresponding to the rear SiNx layer, Fig. 1) directly on a surface of the passivation layer away from the silicon wafer, through injecting a second reaction gas (i.e. SiH4 and NH3) into the coating device (column 1, page 4).
Seiffe does not teach that the passivation layer/SiON layer is doped, or that the method of his invention includes the step of, after depositing the doped passivation layer on the back side of the silicon wafer, depositing a silicon oxynitride layer directly at the surface of the doped passivation layer away from the silicon wafer, through injecting the first reaction gas into the coating device.
To solve the same problem of providing a silicon solar cell (paragraph [0017]) with silicon oxynitride passivation layers, Hu teaches a structure in which a silicon oxide passivation structure comprises a layer of N-doped silicon oxynitride 112a closest to the underlying substrate, followed by an undoped layer of silicon oxynitride 112b (Fig. 1, paragraph [0027]).
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 silicon oxynitride layer of Seiffe to have a double-layered structure including an N-doped layer of silicon oxynitride closest to the silicon wafer and an undoped layer of silicon oxynitride on the N-doped silicon oxynitride layer, based on Hu’s teachings that this is a suitable configuration for a silicon oxynitride passivation layer for use in a silicon solar cell.
Hu is silent regarding the method by which the doped/undoped silicon oxynitride layers of his invention are formed.
Therefore, modified Seiffe does not teach that the doped passivation layer is deposited by injecting a dopant gas and a first reaction gas into a coating device.
To solve the same problem of providing a silicon wafer with SiON layers disposed on either side of it, Brinkmann teaches a method in which PECVD is used to dispose a double-layered stack of undoped SiON and PH3-doped SiON on either side of a silicon wafer (section 3.3, column 2, page 186 through column 1, page 187). Additional details are given in section 2 (column 1, page 181), in which Brinkmann teaches that SiH4, N2O, and H2 are used to form the undoped SiON, and SiH4, N2O, H2, and PH3 are used to form the doped SiON layer.
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 deposition of the N-doped silicon oxynitride layer deposition of modified Seiffe using PECVD with SiON, and SiH4, N2O, H2, and PH3 gases to form the doped silicon oxynitride layer, followed by PECVD using SiH4, N2O, and H2 to form the undoped silicon oxynitride layer, based on Brinkmann’s disclosure that these are suitable reaction conditions to form these types of layers.
This modification teaches the limitations of Claim 1, wherein the method comprises depositing a doped passivation layer directly on a back surface of a silicon wafer, through injecting a dopant gas (PH3) and a first reaction gas (i.e. SiH4, N2O, H2, per Brinkmann) into a coating device.
This modification teaches the limitations of Claim 1, wherein the method comprises, after depositing the doped passivation layer on the back side of the silicon wafer, depositing a silicon oxynitride layer directly at the surface of the doped passivation layer away from the silicon wafer, through injecting the first reaction gas (i.e. SiH4, N2O, H2, per Brinkmann) into the coating device.
This modification teaches the limitations of Claim 1, wherein the method comprises depositing an internal reflection layer (corresponding to the rear SiNx layer of Seiffe, Fig. 1) directly on a surface of the passivation layer away from the silicon wafer, through injecting a second reaction gas (i.e. SiH4 and NH3) into the coating device (Seiffe, column 1, page 4).
In reference to Claim 3, Brinkmann teaches that the first reaction gas comprises SiH4, NH3, and N2O (column 1, page 181) and the doped passivation layer is a doped silicon oxynitride layer.
Seiffe teaches that the second reaction gas comprises SiH4 and NH3 , and the internal reflection layer is a silicon nitride layer (column 1, page 4).
In reference to Claim 8, Brinkmann teaches that the silicon oxynitride layers of his invention have a hydrogen content of 15-30%.
Therefore, this disclosure teaches the limitations of Claim 8, wherein a content of hydrogen in the doped silicon oxynitride layer ranges from 18 to 30 in atomic percentage.
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 18-30% lies within the taught range of 15-30%.
It is the Examiner’s position that, because modified Seiffe teaches the same method and products as recited in Claim 8, there is reasonable basis conclude that the charge density of the doped silicon oxynitride layer of modified Seiffe meets the limitations of Claim 8.
However, if this is not found to be the case, then it is the Examiner’s position that it would have been obvious to one of ordinary skill in the art at the time the instant invention was filed to have arrived at the claimed charge density, based on the teachings of Brinkmann.
Specifically, Brinkmann teaches that the dopant concentration and oxygen concentration of the doped silicon oxynitride film can be controlled to modify the conductivity of the resulting film (Fig. 7 and associated text).
Therefore, it is the Examiner’s position that the routine optimization of the composition of the doped silicon oxynitride film, in order to optimize its conductivity, would have led one of ordinary skill in the art at the time the instant invention was filed to have arrived at a structure having the charge density recited in Claim 8, without undue experimentation.
In reference to Claim 9, Seiffe teaches that, before depositing the doped passivation layer on the back surface of the silicon wafer through injecting the dopant gas and the first reaction gas into the coating device, the method further comprises polishing the silicon wafer by using an acidic solution (section III A, paragraph 1, page 4).
Claims 4-6 are rejected under 35 U.S.C. 103 as being unpatentable over Seiffe, et al. (J. Appl. Phys. 109, 034105 (2011)), in view of Hu, et al. (U.S. Patent Application Publication 2012/0167973 A1) and Brinkmann, et al. (Solar Energy Materials and Solar Cells 108 (2013) 180-188), and further in view of Li, et al. (U.S. Patent 10,991,834)
In reference to Claim 4, modified Seiffe teaches that the dopant gas comprises a gas comprising phosphorus (Brinkmann, column 1, page 181).
Modified Seiffe does not teach that depositing the internal reflection layer on the surface of the silicon oxynitride layer away from the doped passivation layer comprises: depositing a plurality of internal reflection layers sequentially stacked on the surface of the silicon oxynitride layer away from the doped passivation layer.
Instead, Seiffe teaches that the internal reflection layer is a single layer of silicon nitride (Fig. 1).
To solve the same problem of providing a silicon wafer with a rear passivation structure comprising layers of silicon oxynitride and silicon nitride, Li teaches that suitable forms for a rear silicon nitride antireflection layer include a single layered structure (as in Seiffe), or a three-layered structure, in which each layer has a different refractive index, all of which are deposited by PECVD using SiH4 and NH3, as in Seiffe (Li, column 9, lines 20-44).
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 used the PECVD method of Li to form the silicon nitride internal reflection layer of modified Seiffe to have three layers, each with a different refractive index, based on Li’s disclosure that suitable forms for a rear silicon nitride antireflection layer disposed on a silicon oxynitride layer include a single layered structure (as in Seiffe), or a three-layered structure, in which each layer has a different refractive index.
This modification teaches the limitations of Claim 4, wherein depositing the internal reflection layer on the surface of the silicon oxynitride layer away from the doped passivation layer comprises: depositing a plurality of internal reflection layers sequentially stacked on the surface of the silicon oxynitride layer away from the doped passivation layer.
In reference to Claim 5, Li is silent regarding the pattern of the refractive index values in the multi-layered antireflection layer of his invention.
Therefore, he does not teach that a refractive index decreases gradually along a direction pointing away from the silicon wafer among the plurality of internal reflection layers.
However, it is the Examiner’s position that the claimed structure is one of only a finite number of options for the pattern of dielectric constant in the three stacked silicon nitride layers (i.e. the layers can increase in refractive index moving away from the substrate, the layers can decrease in refractive index moving away from the substrate, the layers can increase and decrease in refractive index, with the middle layer having a higher refractive index than the outer layers, or the layers can decrease and increase in refractive index, with the middle layer having a lower refractive index than the outer layers).
Therefore, it is the Examiner’s position that one of ordinary skill in the art would be motivated to choose any of these finite number of options for the relative refractive indices in the silicon nitride layers, including the structure recited in Claim 5, in order to optimize the reflection into the solar cell.
In reference to Claim 6, modified Seiffe teaches that a quantity of internal reflection layers in the plurality of internal reflection layers is three (Li, column 9, lines 20-44).
Claims 5-7 are rejected under 35 U.S.C. 103 as being unpatentable over Seiffe, et al. (J. Appl. Phys. 109, 034105 (2011)), in view of Hu, et al. (U.S. Patent Application Publication 2012/0167973 A1), Brinkmann, et al. (Solar Energy Materials and Solar Cells 108 (2013) 180-188), and Li, et al. (U.S. Patent 10,991,834), and further in view of Qiu, et al. (Applied Physics Letters, 96, 141116 (2010)).
In reference to Claim 5, Li is silent regarding the pattern of the refractive index values in the multi-layered antireflection layer of his invention.
Therefore, he does not teach that a refractive index decreases gradually along a direction pointing away from the silicon wafer among the plurality of internal reflection layers.
To solve the same problem of providing a multilayered antireflection structure comprising silicon nitride and silicon oxynitride for a silicon solar cell, Qiu teaches a pattern in which the refractive index of the stacked/graded layers decreases with increasing distance from the solar cell substrate (Fig. 1, column 2, page 1).
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 structured the refractive indices of the silicon nitride layers of modified Seiffe so that the refractive index decreases gradually along a direction pointing away from the silicon wafer among the plurality of internal reflection layers, because Qiu teaches that this is a suitable form for a stacked silicon nitride multilayered structure.
In reference to Claim 6, modified Seiffe teaches that a quantity of internal reflection layers in the plurality of internal reflection layers is three (Li, column 9, lines 20-44).
In reference to Claim 7, modified Seiffe as applied to Claim 6 teaches that a first internal reflection layer, a second internal reflection layer, and a third internal reflection layer are arranged along the direction pointing away from the silicon oxynitride layer, as described above (Li, column 9, lines 20-44).
Modified Seiffe teaches that the total thicknesses of the internal reflection layers is 60-180 nm, and the refractive index of each layer is within the range of 2.08-2.11 (Li, column 9, lines 45-52).
Therefore, modified Seiffe does not teach that the silicon nitride layer has the structure recited in Claim 7.
To solve the same problem of providing a multilayered antireflection structure comprising silicon nitride and silicon oxynitride for a silicon solar cell, Qiu teaches that the refractive index of a silicon nitride antireflection layer can be controlled by modifying the silane/ammonia ratio during the deposition of the layer, to achieve refractive indices within the range of 1.61-3.0 (Fig. 1, column 2, page 1).
Therefore, it is the Examiner’s position that it would have been within the ambit of one of ordinary skill in the art at the time the instant invention was filed to have optimized the silane:ammonia ratio during the deposition of the silicon nitride layer of modified Seiffe to have arrived at the structure of Claim 7, without undue experimentation.
Response to Arguments
The Applicant’s arguments with respect to the prior art rejections of claims presented in the non-final rejection of 8/19/2025 have been fully considered and are persuasive. Therefore, these rejections have been withdrawn. However, upon further consideration, new grounds of rejection are made in view of modified Seiffe, as described fully above.
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.
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/SADIE WHITE/Primary Examiner, Art Unit 1721