DETAILED ACTION
Allowable Subject Matter
Claims 2-8 and 12-13 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter.
Most of the limitations recited in claim 2 are known in prior art. For example, see US-2013/0321680 by Kumano, FIG. 3E, which teaches the connection structure (explained below) includes a front side conductive feature (310) disposed on the front side and a back side through substrate via (TSV) (6812) extending into the back side within the peripheral region (see FIG. 3E)”.
This means, Examiner would have to argue for above combination of references (Kim/Li and Kumano) teaching all the limitations in combination. However, Examiner is not ready to argue for obviousness of such a combination, since he would have to argue that 6811 metal structure is analogous to “connection structure of metals” taught by Kim and it does not appear to be a fair argument. Hence, indication of allowable subject matter.
Claim 12 recites in part “a pad structure extending into a dielectric layer on the front side; wherein the contact pad is directly below the pad structure but electrically isolated from the pad structure”. The prior art of Kim and Li does not disclose such pad/contact pad when taken together with limitations of claims 9 & 10.
Claim 13 recites same key limitations as claim 2 (the TSV being part of “connection structure”) and is indicated as allowable for similar reasons.
Claims 21-25 are allowed.
The following is an examiner’s statement of reasons for allowance.
Claim 21 requires in part “a back side metal grid in the pixel region, wherein the back side metal grid is over the back side and is grounded to the semiconductor; a contact pad in the peripheral region; and a direct electrical connection between the in-substrate metal grid and the contact pad, wherein the in-substrate metal grid, the contact pad, and the direct electrical connection are electrically isolated from the semiconductor substrate so that a voltage on the in-substrate metal grid is continuously variable with a voltage on the contact pad”.
The above limitations basically require that certain objects (back side metal grid and semiconductor) are to be grounded and certain other objects (see list above) are to be electrically isolated from the first set of objects and are NOT to be grounded. This combination of teachings is not found in the prior art.
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.”
Claim Rejections - 35 USC § 103
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 of this title, 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.
Claims 1, 9-11 & 14-15 are rejected under 35 U.S.C. 103 as being unpatentable over (US-2021/0168336) by Kim et al (“Kim”) in view of (CN-10-9786397) by Li et al (“Li” (English Translation is included with this Action).
Regarding claim 1, Kim discloses in FIGs. 9-10C and related text, e.g., an image sensor comprising:
a semiconductor substrate (FIG. 10A, 100) including a front side (100a), a back side (100b), a pixel region (FIG. 9, all the “PX”), and a peripheral region (outside of all the “PX”);
photodetector pixels (110) in an array (array is seen in FIG. 9) within the pixel region;
a back side isolation structure (101/105) extending into the back side between the photodetector pixels, the back side isolation structure including an in-substrate metal grid (105) and a dielectric liner (101) separating the in-substrate metal grid from the semiconductor substrate;
a contact pad (FIG. 9/10C, PAD) in the peripheral region; and
a connection structure of metals (FIG. 10C, GRc/TCP) extending from the in-substrate metal grid to the contact pad.
Kim does not disclose “connection structure of metals … forming an electrical connection between the in-substrate metal grid and the contact pad”.
Li discloses in FIG.1 and related text, e.g., “connection structure of metals (143)… forming an electrical connection (see Abstract) between the in-substrate metal grid (113/115) and the contact pad (142)”.
It would have been obvious to one of ordinary skill in the art at the time of the invention to modify the device of Kim with “connection structure of metals … forming an electrical connection between the in-substrate metal grid and the contact pad” as taught by Li, in order to “so as to reduce dark current and hot noise point of the photodiode so as to improve the imaging quality” (Li, Abstract).
Regarding claim 9, the combined device of Kim and Li disclose in cited figures and related text, e.g., further comprising: a back side metal grid (FIG. 10C, Gra) in the pixel region;
wherein the back side metal grid is outside the semiconductor substrate (see FIG. 10C).
Regarding claim 10, the combined device of Kim and Li disclose in cited figures and related text, e.g., wherein connection structure coupling the in-substrate metal grid directly to the contact pad comprises a conductive bridge (FIG. 10C, directly above TCP; also, the GRc also qualifies as “conductive bridge”) extending laterally from the contact pad on the back side.
Regarding claim 11, the combined device of Kim and Li disclose in cited figures and related text, e.g., wherein the conductive bridge and the contact pad are a unitary structure (by definition; both the portion directly above TCP, and GRc are both fused together with the PAD; hence, “unitary”; also, keep in mind that “making separate” or “making integral” are valid obviousness rationales per MPEP; hence, if Applicant wishes to argue, such limitations are at the very least obvious in light of MPEP, and would not be patentable in claim drawn to device, anyway, since they are referring to the method of making limitations, however indirectly).
Regarding claim 14, the combined device of Kim and Li disclose in cited figures and related text, e.g., an image sensor comprising:
a semiconductor substrate including a front side, a back side, a pixel region, and a peripheral region (see claim 1);
photodetector pixels in an array within the pixel region (see claim 1);
a back side isolation structure extending into the back side and between adjacent pairs of the photodetector pixels (see claim 1); and
a contact pad ( see claim 1);
wherein the back side isolation structure comprises an in-substrate metal grid and a dielectric liner separating the in-substrate metal grid from the semiconductor substrate (see claim 1); and
the in-substrate metal grid is coupled to the contact pad by a continuous (there is no physical discontinuity; the different pieces were manufactured at separate steps, but the result is a “continuous” object) metal structure so that a voltage on the in-substrate metal grid is continuously variable with a voltage on the contact pad (see claim 1, Abstract of Li, and related portions of description; the voltage is controlled by the contact pad; hence, if/when voltage on contact pad changes, the voltage on “metal grid” will also change; as far as whether it is operated in “continuously variable” regime is not a patentable concept in a claim drawn to device, since this is not a structure, but a method of operating limitation; structure is capable of being operated in such way, since Li shows direct connection between pad and grid; hence, whatever voltage is set on pad (such as “continuously variable”), this is the voltage that grid will have; thus meeting limitations).
Regarding claim 15, the combined device of Kim and Li disclose in cited figures and related text, e.g., wherein the continuous metal structure coupling between the in-substrate metal grid and the contact pad bypasses the front side (see FIG. 1 of Li).
Conclusion
Additional references (if any) are cited on the PTO-892 as disclosing similar features to those of the instant invention.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Alexander Belousov whose telephone number is (571)-272-3167. The examiner can normally be reached on 10 am-4 pm. If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, Jeff Natalini can be reached on 571-272-2266. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/Alexander Belousov/Patent Examiner, Art Unit 2894
09/11/26
/JEFF W NATALINI/Supervisory Patent Examiner, Art Unit 2818
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