DETAILED ACTION
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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 4/7/2026 has been entered.
Response to Arguments
Applicant's arguments filed 4/7/2026 have been fully considered but they are not persuasive.
Regarding the argument against the rejection of claim 1, Applicant states that Borthakur and Komuro do not disclose “a micro-topography region, comprising a surface portion of the substrate adjacent to the trench and above the floating diffusion region, wherein the surface portion of the substrate has a height, relative to the plurality of photodiodes, in a range from approximately 0.01 micrometers (µm) to approximately 0.2 µm” (though remarks do not have the entirety of the claim language), Examiner respectfully disagrees.
Examiner will provide a more annotated Fig. 6 of Borthakur in the rejection to follow, though further explanation will be provided here. Examiner is still unsure on Applicant’s “micro-topography region” as it again does not appear to be a physical element to the structure, as was also mentioned in the interview of 3/11/2026. As such, the “self-denoted microtopography region” is sufficient to encompass a surface portion of the substrate adjacent to the trench, particularly at the top of the micro-topography region, as will be labeled in the rejection to follow. The surface region is pointed toward as such as above it is the photodiode region. While the photodiode is a part of the substrate (similar to Fig. 3B of the present application), one of ordinary skill in the art could reasonably denote the area below the micro-topography region to be the substrate, and above the micro-topography region to be the photodiode, as it appears to have been done in the present application.
Applicant argues the denoted micro-topography region does not correspond to “a surface portion of the substrate adjacent to the trench and above the floating diffusion region”, but to a variation in the depth of the isolation structure. However, Examiner is of the opinion Applicant has not sufficiently defined the “surface portion of the substrate”, and the rejection to follow will indicate what Examiner assumes is the surface portion of the substrate.
Regarding the argument of “amended claim 1 explicitly requires "the micro-topography region comprising a surface portion of the substrate," which necessarily corresponds to a physical surface feature of the substrate itself” on page 10 of the Remarks, Examiner does not find this sufficient. There does not appear to be indication of this physical attribution of the micro-topography region to a surface feature of the substrate in any of the figures or the specification to the Examiner’s knowledge.
Regarding the argument on page 10 of the Remarks of the combination of references failing to teach the microtopography region in relation to the floating diffusion region, a new annotated Fig. 6 will be included in the rejection to follow.
Status of the Claims
Claims 1-21 are pending in the application and are currently being examined. Claim 1 has been amended. New claim 21 has been added.
Drawings
The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the surface portion of the substrate adjacent to the trench and above the floating diffusion region must be shown or the feature(s) canceled from the claim(s). No new matter should be entered.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
The drawings are objected to because the unlabeled rectangular boxes in Figs. 1 and 6 should be provided with descriptive labels (much like in Fig. 7). Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-5 and 21 rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Regarding claims 1 and 21, both recite the feature “surface portion of the substrate”. This is considered to be new matter as neither the drawings nor the written specification describe such a location for one of ordinary skill in the art to determine this feature’s location. For the purposes of examination, the surface portion will be the area noted in the annotated Fig. 4C.
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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.
Claim(s) 1 and 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Borthakur et al. (US 2023/0215960 A1, hereafter Borthakur) in view of Komuro et al. (US 2022/0293658 A1, hereafter Komuro).
Regarding claim 1, Borthakur teaches a semiconductor structure, comprising:
a plurality of photodiodes (single-photon avalanche diode (SPAD), 204, [0021]);
a deep trench isolation (DTI) structure (isolation structure, 252, [0045]) electrically isolating the plurality of photodiodes (240).
Borthakur is silent on a floating diffusion region associated with the plurality of photodiodes. However, Komuro teaches a device similar to Borthakur in which there are floating diffusion regions (FD1 and FD2, [0092]) associated with the photodiodes (PD, [0084]). One skilled in the art would have found it obvious to include floating diffusion regions at a layer lower than the deep trench isolation regions in order to act as charge accumulation portions, as taught by Komuro [0092]. Thus, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the device of Borthakur to include floating diffusion regions as taught by Komuro.
Borthakur in view of Komuro is silent on the DTI structure is formed in a trench of a substrate; and a micro-topography region comprising a surface portion of the substrate adjacent to the trench and above the floating diffusion region, wherein the surface portion of the substrate has a height, relative to the plurality of photodiodes, in a range from approximately 0.01 micrometers (µm) to approximately 0.2 µm.
However, Borthakur teaches the DTI structure (252) has a micro-topography region (see annotated Fig. 6. As the micro-topography does not appear to be a physical structure, a self-denoted micro-topography region is suitable under BRI) that comprises a surface portion of the substrate (see annotated Fig. 6) adjacent to the trench and above the floating diffusion region (F1 and F2 from Komuro in annotated Fig. 6) a varying depth of the DTI structure (the depth of the isolation structure 252 can be between 20% (Borthakur) and 100% (seen in Fig. 4 of Komuro) of the substrate thickness [0054]). While Borthakur does not explicitly teach the surface portion of the substrate has a height, relative to the plurality of photodiodes, in a range from approximately 0.01 µm to approximately 0.2 µm, one of ordinary skill would know to adjust the DTI structure depth through routine experimentation (see MPEP 2144.05). One of ordinary skill in the art would reach a depth allowing for the relative height of the surface portion of the substrate in a range from approximately 0.01 µm to approximately 0.2 µm in order to confine light to its own pixel and prevent leakage of incident light from adjacent pixels as Komuro teaches in [0110].
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Regarding claim 21, Borthakur in view of Komuro teach the semiconductor structure of claim 1. Borthakur in view of Komuro further teach the surface portion of the substrate has a non-planar surface profile. See annotated Fig. 6 in which the profile comes up to “points”.
Claim(s) 2-5 is/are rejected under 35 U.S.C. 103 as being unpatentable over Borthakur in view of Komuro as applied to claim 1 above, and further in view of Bai et al. (US 2024/0071846 A1, hereafter Bai).
Regarding claim 2, Borthakur in view of Komuro teach the DTI structure having a first depth in a range from approximately 2.0 µm to approximately 3.0 µm. While Borthakur does not explicitly teach this depth, Borthakur discloses a substrate thickness in the range of 5 to 20 microns [0051]. Pairing this with the fact that the depth of the isolation structure can be between 20% and 100% (as noted in the above rejection of claim 1) of the substrate thickness, one of ordinary skill in the art can set the depth of the isolation structure and thickness of the substrate such that it extends beyond the photodiodes and reach a depth between 2 and 3 microns.
Borthakur in view of Komuro is silent on the DTI structure having a first width in a range from approximately 0.1 µm to approximately 0.2 µm. However, one of ordinary skill in the art would find it obvious to look elsewhere for widths utilized in these devices. Bai discloses a device similar to Borthakur in view of Komuro in which the DTI can have a width on 0.15 microns [0044]. Thus, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the invention of Borthakur in view of Komuro to include a width as taught by Bai to get the expected result of a functional device.
Regarding claim 3, Borthakur in view of Komuro in further view of Bai teach the semiconductor structure of claim 2, wherein the DTI structure has the first width and the first depth at a location of the DTI structure that is between two adjacent photodiodes of the plurality of photodiodes. As seen in Fig. 6 of Borthakur, the DTI are located between adjacent photodiodes.
Regarding claim 4, Borthakur in view of Komuro in further view of Bai teach the semiconductor structure of claim 2, wherein the DTI structure has a second width in a range from approximately 0.12 µm to approximately 0.4 µm and has a second depth in a range from approximately 2.0 µm to approximately 3.5 µm. While Borthakur does not explicitly teach this depth, Borthakur discloses a substrate thickness in the range of 5 to 20 microns [0051]. Pairing this with the fact that the depth of the isolation structure can be between 20% and 100% (as noted above in the rejection of claim 1) of the substrate thickness, one of ordinary skill in the art can set the depth of the isolation structure and thickness of the substrate such that it extends beyond the photodiodes and reach a depth between 2 and 3 microns.
Borthakur in view of Komuro is silent on the DTI structure having a second width in a range from approximately 0.12 µm to approximately 0.4 µm. However, one of ordinary skill in the art would find it obvious to look elsewhere for widths utilized in these devices. Bai discloses a device similar to Borthakur in view of Komuro in which the DTI can have a width on 0.15 microns [0044]. Thus, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the invention of Borthakur in view of Komuro to include a width as taught by Bai to get the expected result of a functional device.
Regarding claim 5, Borthakur in view of Komuro in further view of Bai teach the semiconductor structure of claim 4, wherein the DTI structure has the first width and the first depth at a location of the DTI structure that is between two adjacent photodiodes of the plurality of photodiodes. While Borthakur is silent on the depth being between four of the plurality of photodiodes, the trenches are continuous [0045]. Thus, one of ordinary skill in the art would find it obvious that the trench of a second depth and a width of 0.15 microns would exist between four of the plurality of photodiodes.
Allowable Subject Matter
Claims 6-20 are allowed.
The following is an examiner’s statement of reasons for allowance:
Claims 6-20 are allowed primarily because the prior art of record cannot anticipate or render obvious the following limitations, in combination as recited in independent claim(s) 6: “wherein a remainder of the plug is only at an intersection between the at least four photodiodes”;
and independent claim 18: “wherein a remainder of the plug is only in the portion of the trench that is located between four corners of a subset of the plurality of photodiodes”.
The closest prior art of record, Borthakur and Zhang et al. (US 2017/0294336 A1) teaches a deep trench structure with a plug but fails to teach “a remainder of the plug is only at an intersection between the at least four photodiodes/in the portion of the trench that is located between four corners of a subset of the plurality of photodiodes”, nor could Examiner find any reason for this limitation.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SAMMANTHA K SALAZ whose telephone number is (571)272-2484. The examiner can normally be reached Monday - Friday 8:00am-5:00pm.
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, N. Drew Richards can be reached at 571-272-1736. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/SAMMANTHA K SALAZ/Examiner, Art Unit 2892
/ERIC W JONES/Primary Examiner, Art Unit 2892
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