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 .
Claims 1 - 20 are pending
Claims 7, 8, 14 - 20 are withdrawn
Species A is withdrawn
Claims 1-6 and 9 - 13 are under consideration
Species B is under consideration
Election/Restrictions
Applicant’s election without traverse of Invention I, directed to a method of fabricating a deposition mask, and Species B, directed to the dummy/additional inorganic film embodiment illustrated in FIG. 16, including claims 1-6 and 9-13, in the reply filed July 28, 2026, is acknowledged.
Claims 14-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to nonelected Invention II. Election was made without traverse in the reply filed July 28, 2026.
Claims 7-8 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to nonelected Species A, there being no allowable generic or linking claim. Election was made without traverse in the reply filed July 28, 2026.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 5 and 6 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
The term “adjusting ” in claim 5 is a relative term which renders the claim indefinite. The term “adjusting” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention.
Specifically, claim 5 recites a KOH wet etching process performed “by adjusting an etch ratio in respect to silicon oxide in the second protective layer and silicon (Si) in the lower silicon substrate.” The term “adjusting” renders the scope of the claim unclear because neither the claim nor the specification appears to identify what parameter is changed to accomplish the adjustment, a reference or target etch ratio, or another objective standard for distinguishing an adjusted etch ratio from the etch-rate relationship present during KOH wet etching of the silicon oxide and silicon. Accordingly, one of ordinary skill in the art would not be reasonably apprised of what constitutes the claimed “adjusting.”
For purposes of examination and advancement of prosecution, claim 5 is interpreted as requiring controlling or setting the etch-rate ratio of the silicon oxide in the second protective layer to the silicon in the lower silicon substrate during the KOH wet etching process.
Claim 6 is rejected as being dependent upon indefinite claim 5. Claim 6 does not cure the indefiniteness discussed above.
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 5 are rejected under 35 U.S.C. 103 as being unpatentable over Hwang et al. (KR-20210083698-A) in view of Koba (US 6,468,701 B1).
Regarding claim 1, Hwang teaches a method of fabricating a deposition mask (manufacturing shadow mask 30 for deposition of material through a mask pattern onto wafer substrate 32; paragraphs [0001], [0032], [0048]). Hwang continues to teach preparing a silicon on insulator (SOI) substrate comprising an upper silicon substrate, a lower silicon substrate, and an insulating layer between the upper silicon substrate and the lower silicon substrate (wafer module 18 comprises top silicon layer 16, insulating
layer 14, and base layer 12; insulating layer 14 separates top silicon layer 16 from base layer 12; when base layer 12 is silicon, the wafer module is an SOI wafer, and the described shadow-mask fabrication method proceeds using the SOI wafer module; paragraphs [0032]-[0037]).
Hwang further teaches forming a mask membrane having a plurality of openings by patterning the upper silicon substrate (top silicon layer 16 is patterned by etching to form thin mask sheet 22 having a fine mask pattern, and deposition particles pass through the mask pattern of shadow mask 30 onto wafer substrate 32; paragraphs [0038]-[0040], [0048]). Hwang teaches forming a cell opening by patterning the lower silicon substrate (silicon base layer 12 is patterned by etching the central portion of base layer 12 to form mask frame 24 supporting mask sheet 22, thereby forming an opening through the central portion of the lower silicon substrate; paragraph [0041]).
Hwang does not expressly teach, after forming the mask membrane having the plurality of openings by patterning the upper silicon substrate, forming a first protective layer on the upper silicon substrate and a second protective layer on the lower silicon substrate, followed by forming the cell opening by patterning the lower silicon substrate and removing the first protective layer and the second protective layer.
Koba teaches forming a first protective layer on the upper silicon substrate and a second protective layer on the lower silicon substrate after forming the mask membrane having the plurality of openings by patterning the upper silicon substrate (after first silicon layer 10 is selectively etched to form mask pattern 3 and the resist is removed, passivation films are formed on the top surface of patterned first silicon layer 10 and on the bottom surface of lower silicon bulk layer 22; the passivation films may comprise silicon nitride; column 13, lines 22-34).
Koba further teaches forming the cell opening by patterning the lower silicon substrate (the passivation film on the bottom surface of lower silicon bulk layer 22 is patterned and used as a mask during selective wet etching using potassium hydroxide of lower silicon layers 22 and 21 until silicon dioxide film 11 is exposed; column 13, lines 34-61). Koba also teaches removing the first protective layer and the second protective layer (after the backside processing, the first and second passivation films are completely removed; column 13, lines 62-65; column 14, lines 1-3).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Hwang to form protective layers on the upper silicon substrate and lower silicon substrate after formation of the mask membrane and before patterning the lower silicon substrate, and to remove the protective layers after the backside processing, because Koba teaches this known process sequence in a similar silicon-mask fabrication method, including forming passivation films on both surfaces after formation of the silicon mask pattern and using the backside passivation film as an etch mask during selective backside etching of the supporting silicon. Applying Koba’s known passivation technique to Hwang’s SOI silicon shadow-mask fabrication method would have predictably provided passivation of the silicon surfaces while permitting selective patterning of the lower silicon substrate to form the supporting mask structure. Use of a known technique to improve similar methods in the same way is obvious. See MPEP § 2141 III(C).
Regarding claim 2, modified Hwang teaches the limitations of claim 1 as discussed above. Modified Hwang further teaches wherein the insulating layer comprises silicon oxide (insulating layer 14 may be formed mainly of a silicon oxide film (SiO₂); paragraph [0034]).
Regarding claim 3, modified Hwang teaches the limitations of claim 1 as discussed above. Modified Hwang further teaches wherein the patterning of the upper silicon substrate comprises forming a first photoresist pattern on the upper silicon substrate (etching resist 20 is formed on top silicon layer 16 by applying a photoresist, placing a photomask having a predetermined pattern, performing exposure, and removing the exposed portion; paragraph [0039]).
Modified Hwang further teaches forming the plurality of openings by using the first photoresist pattern (top silicon layer 16 is etched in regions not covered by etching resist 20 to form mask sheet 22 having the fine mask pattern through which deposition material subsequently passes; paragraphs [0038]-[0039], [0048]). Modified Hwang teaches removing the first photoresist pattern (after completion of the etching process for top silicon layer 16, etching resist 20 is removed; paragraph [0040]).
Regarding claim 5, modified Hwang teaches the limitations of claim 3 as discussed above.
Modified Hwang does not expressly teach wherein the forming of the cell opening comprises KOH wet etching process by adjusting an etch ratio in respect to silicon oxide in the second protective layer and silicon (Si) in the lower silicon substrate.
Koba teaches wherein the forming of the cell opening comprises KOH wet etching process (a passivation film pattern is used as a mask during selective wet etching using a potassium hydroxide solution to etch lower silicon layers 22 and 21; column 13, lines 41-49). Koba further teaches silicon oxide in the second protective layer (first and second passivation inorganic films 114-1 and 114-2 comprising silicon dioxide are formed on opposite surfaces of the combined silicon substrates to provide passivation during subsequent etching; column 1, lines 60-65; column 2, lines 1-12).
Koba also teaches an etch-rate relationship between silicon oxide and silicon during KOH wet etching (when potassium hydroxide solution is used as the etchant, a silicon insulating layer such as silicon oxide has a much lower etching rate than the boron-implanted silicon layer; column 8, lines 1-8).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the method of modified Hwang to use silicon oxide for the second protective layer during the KOH wet etching process and thereby set the etch-rate relationship between the silicon oxide protective layer and the silicon of the lower silicon substrate because Koba teaches silicon dioxide as a known passivation material for protecting silicon during etching and further teaches that silicon oxide has a much lower etching rate than boron-implanted silicon when potassium hydroxide is used as the etchant. Substitution of silicon oxide for Koba’s silicon nitride passivation material would therefore have predictably provided an etch-resistant protective layer during selective KOH etching of the lower silicon substrate. Simple substitution of one known element for another to obtain predictable results is obvious. See MPEP § 2141 III(B).
Claims 4 and 12-13 are rejected under 35 U.S.C. 103 as being unpatentable over Hwang et al. in view of Koba, as applied to claims 1 and 3 above, and further in view of Lee (KR-20210096891-A).
Regarding claim 4, modified Hwang teaches the limitations of claim 3 as discussed above.
Modified Hwang does not expressly teach wherein the forming of the first protective layer and the second protective layer comprises performing thermal oxidation process with respect to the upper silicon substrate and the lower silicon substrate, respectively.
Lee teaches forming an etch-resistant silicon oxide layer on a silicon substrate by performing a thermal oxidation process (opening insulating portion M1 is formed on silicon substrate 40′ to impart etch resistance, wherein opening insulating portion M1 may comprise silicon oxide formed using thermal oxidation; paragraph [0050]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the method of modified Hwang to form the first protective layer and the second protective layer by performing thermal oxidation with respect to the respective silicon surfaces because Lee teaches thermal oxidation as a known technique for forming a silicon oxide protective layer on a silicon substrate to impart etch resistance. Applying Lee’s known thermal-oxidation technique to the silicon protective layers of modified Hwang would have predictably formed silicon oxide protective layers suitable for protecting the silicon surfaces during subsequent etching. Use of a known technique to improve similar methods in the same way is obvious. See MPEP § 2141 III(C).
Regarding claim 12, modified Hwang teaches the limitations of claim 1 as discussed above.
Modified Hwang does not expressly teach wherein the forming of the mask membrane comprises forming a cross-section of the mask membrane into an inverse taper shape.
Lee teaches wherein the forming of the mask membrane comprises forming a cross-section of the mask membrane into an inverse taper shape (silicon layer 20 functions as the mask film and includes a plurality of mask patterns P, wherein the mask patterns may have slanted sides, a tapered shape, or a shape in which the pattern width widens from top to bottom, thereby providing the surrounding silicon mask film with an inverse-tapered cross-sectional shape; paragraph [0039]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the method of modified Hwang to form the mask openings with Lee’s tapered profile, thereby forming the surrounding mask membrane with an inverse-tapered cross-sectional shape, because Lee teaches that forming the mask pattern at an angle or in a tapered shape prevents non-uniform deposition caused by the shadow effect and permits material traveling diagonally along the inclined surface to contribute to more uniform deposition (paragraph [0032]). Applying Lee’s tapered mask-opening configuration to the mask membrane of modified Hwang would therefore have predictably reduced shadow effects and improved deposition uniformity. Use of a known technique to improve similar methods in the same way is obvious. See MPEP § 2141 III(C).
Regarding claim 13, modified Hwang as further modified by Lee teaches the limitations of claim 12 as discussed above.
Lee further teaches wherein the inverse taper shape of the cross-section of the mask membrane has a shape in which its thickness increases from a bottom surface in an upward direction (the mask pattern P formed through silicon mask layer 20 widens from top to bottom; accordingly, the surrounding silicon mask membrane becomes narrower toward the bottom and increases in lateral thickness from the bottom surface in the upward direction; paragraph [0039]).
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Hwang et al. in view of Koba, as applied to claim 5 above, and further in view of Yoshizawa (US 2006/0269850 A1).
Regarding claim 6, modified Hwang teaches the limitations of claim 5 as discussed above.
Koba further teaches that passivation films formed on opposing surfaces of the silicon structure may both comprise silicon oxide (first and second passivation inorganic films 114-1 and 114-2 comprising silicon dioxide are formed on opposite surfaces of the silicon structure; column 1, lines 60-65; column 2, lines 1-12).
Modified Hwang does not expressly teach wherein the removing of the first protective layer and the second protective layer comprises a strip process by using HF or buffered oxide etchant.
Yoshizawa teaches wherein the removing of a protective layer comprises a strip process by using HF (silicon oxide protection layer 8 is removed by wet etching using a BHF solution including hydrofluoric acid and ammonium fluoride; paragraph [0040]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the method of modified Hwang to remove the first and second silicon oxide protective layer using HF because Koba teaches silicon dioxide passivation films formed on opposing surfaces of a silicon mask structure, while Yoshizawa teach a known HF-containing BHF wet etching process for removing a silicon oxide protection layer after silicon-mask processing. Combining Koba’s silicon oxide passivation layers with Yoshizawas’s known silicon oxide removal process would have predictably removed the protective layers after the silicon etching process, with the passivation layers performing their known protective function and the HF-containing etchant performing its known silicon oxide removal function. Combining prior art elements according to known method to yield predictable results is obvious. See MPEP 2141 § III(A)
Claims 9 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Hwang et al. in view of Koba, as applied to claim 1 above, and further in view of Vazan et al. (US 2018/0315925 A1).
Regarding claim 9, modified Hwang teaches the limitations of claim 1 as discussed above.
Modified Hwang does not expressly teach further comprising depositing a dummy inorganic film covering the mask membrane after the removing of the first protective layer and the second protective layer.
Vazan teaches method of claim 1, further comprising depositing an inorganic film covering a previously fabricated shadow-mask membrane (one or more compensation layers are added to a previously fabricated shadow-mask membrane; after membrane 506 is released from handle substrate 302 by forming cavity 310, compensation layer 306 is formed on the inner surface of structural layer 304 such that the layers are physically joined to collectively define membrane 316; in the depicted embodiment, compensation layer 306 comprises stoichiometric silicon dioxide deposited
by LPCVD; paragraphs [0017], [0064]-[0070]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the method of modified Hwang by depositing Vazan’s compensation layer over the previously fabricated mask membrane after removal of the first protective layer and the second protective layer because Vazan teaches that the compensation layer induces a stress-induced bending moment that at least partially counteracts gravity-induced bending and sag of the shadow-mask membrane (paragraphs [0052], [0069]). Applying Vazan’s compensation-layer technique to the shadow-mask membrane of modified Hwang would have predictably reduced membrane sag and the resulting variation in separation between the shadow mask and the deposition substrate, thereby improving the accuracy and uniformity of shadow-mask deposition. Use of a known technique to improve similar methods in the same way is obvious. See MPEP § 2141 III(C).
Regarding claim 10, modified Hwang as further modified by Vazan teaches the limitations of claim 9 as discussed above.
Vazan further teaches wherein the dummy inorganic film comprises silicon nitride (compensation layer 306 may comprise a tensile-stress material including stoichiometric silicon nitride or silicon-rich silicon nitride; paragraph [0072]).
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Hwang et al. in view of Koba and Vazan et al., as applied to claim 10 above, and further in view of Lee and Kim et al. (US 2019/0198590 A1).
Regarding claim 11, modified Hwang as further modified by Vazan teaches the limitations of claim 10 as discussed above.
Vazan further teaches that the deposited dummy inorganic film may extend onto the interior walls of the mask openings and that the thickness of the deposited film affects the dimensions of the openings (compensation layer 306 is formed after apertures 126 and may deposit on the interior walls of each aperture, thereby reducing the aperture size; the thickness of compensation layer 306 is a selected parameter; paragraphs [0069]-[0071]).
Modified Hwang as further modified by Vazan does not expressly teach so that a cross-section of a mask opening in the mask membrane has a taper shape.
Lee teaches forming a mask opening having a tapered shape (the pattern P of the FMM mask may be formed at an angle or in a tapered shape to prevent non-uniform deposition of pixels caused by the shadow effect, thereby permitting organic material traveling diagonally along the inclined surface to contribute to uniform deposition; paragraphs [0032] and [0039]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the method of modified Hwang as further modified by Vazan so that the cross-section of the mask opening has a tapered shape because Lee teaches that a tapered FMM mask opening reduces non-uniform deposition caused by the shadow effect and permits more uniform deposition of material through the masks opening (paragraph [0032]). Applying lee’s tapered mask opening configuration to the shadow mask oof modified Hwang would therefore have predictably reduced shadow effects and improved deposition uniformity. Using a known technique to improve similar methods in the same way is obvious. See MPEP 2141 III(C).
Modified Hwang as further modified by Vazan and Lee does not expressly teach wherein the depositing of the dummy inorganic film comprises adjusting a deposition thickness on a side of a mask shadow of the mask membrane so that a cross-section of a mask opening.
Kim teaches forming a layer formed along sidewalls with a thickness profile that produces a tapered cross-sectional geometry (bank layer 120 covers the sidewalls of protrusions PM, wherein the thickness of bank layer 120 decreases with decreasing distance to the bottom of the protrusions, thereby providing the sidewalls with a reverse-tapered shape; paragraphs [0077], [0079], [0089]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the method of modified Hwang as further modified by Vazan and Lee to adjust the thickness of the deposited compensation layer deposited along the side of the mask opening to provide the tapered mask-opening geometry cause Kim teaches sidewall-layer configuration in which variation in layer thickness along the sidewall produces a tapered geometry. Vazan already teaches depositing the compensation-layer material on the interior walls of the mask apertures such that the deposited layer alters the aperture dimensions (paragraph [0071]), and Lee provides the reason for providing the mask opening with the tapered geometry to reduce the shadow effect and improve deposition uniformity (paragraph 0032). Applying Kim’s known sidewall-layer thickness configuration to Vazan’s deposited compensation layer would therefore have predictably produced Lee’s desired tapered mask opening. Combining known methods to yield predictable result is obvious . See MPEP § 2141 III(A).
Conclusion
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/JONATHAN L CARTER/Examiner, Art Unit 1713
/ERIN F BERGNER/Primary Examiner, Art Unit 1713
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