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 .
Election/Restrictions
Claim7 is withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected species, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 04 August 2025.
Specification
The lengthy specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification.
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, 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.
Claim(s) 1-6 and 8-12 are is/are rejected under 35 U.S.C. 103 as being unpatentable over US 20200144320 (Seo et al), NPL "Optical properties of Al, Fe, Ti, Ta, W, and Mo at submillimeter wavelengths" (Ordal et al), and NPL "Aluminum Oxide Revisited" (Tropf et al) .
As to Claim 1, Seo teaches an image sensor (Seo Fig 17), comprising:
a substrate including a first surface and a second surface, the first surface and the second surface being opposite to each other (1+15 with surfaces 1a and 1b opposite to each other);
unit pixels in the substrate, the unit pixels including photoelectric conversion regions (pixels shown to right of 29c, photoelectric conversion regions 3 ¶0022);
first pixel separation patterns in the substrate (structure comprising 29c, 21, 23, 25, and 27), the first pixel separation patterns defining the unit pixels (PR separates pixel region AP from adjacent regions), and each of the first pixel separation patterns including a first conductive film and a second conductive film (25 and 29p+29c, respectively); and
microlenses on the second surface of the substrate (41f on top of 1),
wherein the first conductive film extends along sidewalls of the second conductive film, the first conductive film separating the second conductive film from the substrate (25 separates 29c from 1),
wherein the second conductive film has a greater step coverage than the first conductive film (lateral thickness of 29p greater than that of 25).
Seo fails to explicitly teach wherein the first conductive film has a greater reflectance than the second conductive film for a same predetermined wavelength range. While Seo teaches first conductive film 25 may be aluminum oxide (¶0029) and second conductive film may be tungsten (29p may be tungsten ¶0033; 29c may be same material ¶0070), it is silent as to the relative reflectances of those materials at a predetermined wavelength range.
Prior art references Ordal and Tropf provide reference indices of refraction for tungsten and aluminum oxide, respectively. Specifically, Tropf teaches that, at a wavelength ranging between 1.9601 to 2.32542 µm, the refractive index of aluminum oxide ranges 1.73833 to 1.73057 (Tropf Table I, pg 676). Ordal teaches that, at a wavenumber ranging between 4750 and 4500 cm-1 (which corresponds to wavelengths 2.10 and 2.22 µm, respectively), the refractive index of tungsten ranges 1.195 to 1.221 (Ordal Table V, pg 1208).
For light aligned with the normal of a surface, the reflectivity of that material for incident light coming from air relates to its refractive index according to the equation:
R
=
1
-
n
1
+
n
2
where R is reflectivity and n is the refractive index. For all n > 1, reflectivity increases monotonically with n, i.e., a higher n corresponds to a higher reflectivity. Since Ordal and Tropf teach that in the above wavelength range the refractive index of aluminum oxide is greater than that of tungsten, it is then true that the reflectivity of aluminum oxide is greater than that of tungsten, i.e., the first conductive film taught by Seo has a greater reflectance than the second conductive film of Seo for a same predetermined wavelength range.
As to Claim 2, the combination of Seo, Ordal, and Tropf teaches the image sensor of claim 1. For typical values n=1.738 for Al2O3 and 1.438 for SiO2, reflectance for s-polarization light between these two media is greater than 0.7 for angles of
PNG
media_image1.png
560
984
media_image1.png
Greyscale
incidence greater than 0.972 radians (see attached Desmos screenshot), and
the second conductive film has a step coverage of 0.8 or greater (Step coverage of 29p thicker than that of other films as seen in Fig 17, i.e. is greater than 0.8 of the total multilayer thickness)
As to Claim 3, the combination of Seo, Ordal, and Tropf teaches the image sensor as claimed in claim 2. Seo further teaches wherein the first conductive film includes at least one of aluminum, copper, and gold (25 may be aluminum oxide ¶0029)
As to Claim 4, the combination of Seo, Ordal, and Tropf teaches the image sensor as claimed in claim 1, wherein the second conductive film includes at least one of tungsten, polysilicon, and silicide (29p+29c may be tungsten ¶0033).
As to Claim 5, the combination of Seo, Ordal, and Tropf teaches the image sensor as claimed in claim 1. Seo further teaches wherein each of the first pixel separation patterns further includes:
an insulating film extending along sidewalls of the first conductive film, the insulating film separating the first conductive film from the substrate (Seo Fig 17, 21 separates structure from substrate, 21 may be a “fixed charge layer” ¶0029), and
a barrier film between the insulating film and the first conductive film (23 between 21 and 25, 23 a filling insulation layer ¶0029).
As to Claim 6, the combination of Seo, Ordal, and Tropf teaches the image sensor as claimed in claim 1. Seo further teaches wherein each of the first pixel separation patterns further includes a third conductive film between the first conductive film and the second conductive film (Seo 27 between 25 and 29c. 27 may be a silicon nitride layer ¶0035, which is considered to be thermally conductive).
As to Claim 8, the combination of Seo, Ordal, and Tropf teaches the image sensor as claimed in claim 1. Seo further teaches wherein the first pixel separation patterns extend from the second surface of the substrate to only partially penetrate the substrate (Seo first pixel separation pattern does not fully penetrate portion 15 of the substrate).
As to Claim 9, the combination of Seo, Ordal, and Tropf teaches the image sensor as claimed in claim 1. Seo further teaches wherein the second conductive film extends along a bottom surface of the first conductive film (horizontal surface of 29p extends along a bottom surface of horizontal portion of 25).
As to Claim 10, the combination of Seo, Ordal, and Tropf teaches the image sensor as claimed in claim 1. Seo teaches the sensor further comprising second pixel separation patterns extending from the second surface of the substrate, the first pixel separation patterns extending from the first surface of the substrate toward the second pixel separation patterns (pattern in trenches 1to extend from top to bottom surfaces, while first pixel separation pattern extends from first surface upwards towards second pixel separation patterns).
As to Claim 11, the combination of Seo, Ordal, and Tropf teaches the image sensor as claimed in claim 10. Seo further teaches wherein:
each of the second pixel separation patterns includes a fourth conductive film and a fifth conductive film on the fourth conductive film (fourth film 21 and fifth film 23 respectively, where these each may reasonably constitute a thermally conductive film), and
the fourth conductive film extends along sidewalls of the fifth conductive film (21 along sidewalls of 23).
As to Claim 12, the combination of Seo, Ordal, and Tropf teaches the image sensor as claimed in claim 1. Seo further teaches wherein the second pixel separation patterns include an insulating material (second pixel separation patterns comprise 23 which is a filling insulation layer ¶0029).
Claim(s) 13-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 20200227452 (Ishii et al), Seo, Ordal, and Tropf.
As to Claim 13, Ishii teaches an image sensor, comprising:
a substrate including a first surface and a second surface, the first surface and the second surface being opposite to each other (Ishii Fig 1, 110 with surfaces 110F1 and 110F2 respectively);
unit pixels in the substrate, the unit pixels including photoelectric conversion regions (“PX” with conversion regions 120 ¶0044);
first pixel separation patterns defining the unit pixels in the substrate, the first pixel separation patterns filling respective first pixel separation trenches (130 which fill trenches 130T ¶0024);
well regions and floating diffusion regions in the substrate (124 and FD respectively);
transistors on the first surface of the substrate (TG on 110F1);
a wiring structure including an inter-wiring insulating layer, which covers the transistors, and wires in the inter-wiring insulating layer (insulating layer 154 and wires 152); and
microlenses on the second surface of the substrate (186),
wherein each of the first pixel separation patterns includes a first insulating film extending along sidewalls of each of the first pixel separation trenches (132), a first conductive film on the first insulating film (134), and filling each of the first pixel separation trenches (132+134 fill those trenches)
Ishii fails to explicitly teach a second conductive film on the first conductive film or structural details and properties thereof.
Seo teaches a sensor similar to that of Ishii, and explicitly teaches pixel separation patterns which include a first insulating film extending along sidewalls of each of the first pixel separation trenches (21), a first conductive film on the first insulating film (25), and a second conductive film on the first conductive film and filling each of the first pixel separation trenches (29p+29c). Seo further teaches wherein the second conductive film has a greater step coverage than the first conductive film (lateral thickness of 29p greater than that of 25).
The claim would have been obvious because the substitution substituting the pixel separation trench structure of Seo into the device of Ishii would have yielded predictable results to one of ordinary skill in the art.
The combination of Ishii and Seo still fails to teach wherein the first conductive film has a greater reflectance than the second conductive film for a same predetermined wavelength range.
Prior art references Ordal and Tropf, as applied to claim 1 and for the same reasons as those stated above, then teach wherein the first conductive film has a greater reflectance than the second conductive film for a same predetermined wavelength range (see claim 1 rejection & rationale).
As to Claim 14, the combination of Ishii, Seo, Ordal, and Tropf teach the image sensor of claim 13. Ishii further teaches wherein at least some of the well regions extend along sidewalls of respective first pixel separation patterns (124 along direction of sidewall of 130)
As to Claim 15, the combination of Ishii, Seo, Ordal, and Tropf teach the image sensor of claim 13. Ishii further teaches device isolation pattern formed in first surface of substrate, i.e., penetrating part of the substrate (buried insulation layer 140) and first pixel separation pattern penetrating the device isolation pattern (132 penetrates 140)
As to Claim 16, the combination of Ishii, Seo, Ordal, and Tropf teach the image sensor of claim 13. Ishii further teaches wherein at least parts of the transistor are in the substrate (top portion of TG within 110)
As to Claim 17, Ishii teaches an image sensor, comprising:
a substrate including a first surface and a second surface, the first surface and the second surface being opposite to each other (Ishii Fig 1, 110 with surfaces 110F1 and 110F2 respectively);
first pixel separation patterns extending from the first surface toward the second surface of the substrate and filling first pixel separation trenches (130 extend between 110F1/F2 and fill trenches 130T);
unit pixels including photoelectric conversion regions in the substrate, the unit pixels being defined by the first pixel separation patterns (PX include 120, separated by 130); and
microlenses on the second surface of the substrate (186 on top),
wherein each of the first pixel separation patterns includes a first insulating film on sidewalls of each of the first pixel separation trenches (132), a first conductive film on the first insulating film (134), and filling each of the first pixel separation trenches (132+134 fill those trenches)
Ishii fails to explicitly teach a second conductive film on the first conductive film or structural details and properties thereof.
Seo teaches a sensor similar to that of Ishii, and explicitly teaches pixel separation patterns which include a first insulating film extending along sidewalls of each of the first pixel separation trenches (21), a first conductive film on the first insulating film (25), and a second conductive film on the first conductive film and filling each of the first pixel separation trenches (29p+29c). Seo further teaches wherein the second conductive film has a greater step coverage than the first conductive film (lateral thickness of 29p greater than that of 25).
The claim would have been obvious because the substitution substituting the pixel separation trench structure of Seo into the device of Ishii would have yielded predictable results to one of ordinary skill in the art.
The combination of Ishii and Seo still fails to teach wherein the first conductive film has a greater reflectance than the second conductive film for a same predetermined wavelength range.
Prior art references Ordal and Tropf, as applied to claim 1 and for the same reasons as those stated above, then teach wherein the first conductive film has a greater reflectance than the second conductive film for a same predetermined wavelength range (see claim 1 rejection & rationale).
As to Claim 18, the combination of Ishii, Seo, Ordal, and Tropf teaches the image sensor of claim 17. Seo, as applied to claim 17, further teaches the first pixel separation patterns including a third conductive film between the first and second conductive films (27 between 25 and 29c. 27 may be a silicon nitride layer ¶0035 which is considered to be a thermally conductive material).
As to Claim 19, the combination of Ishii, Seo, Ordal, and Tropf teaches the image sensor of claim 17. Seo, as applied to claim 17, further teaches wherein each of the first pixel separation patterns further includes a barrier film between the first insulating film and the first conductive film (Seo Fig 17, 23 between 21 and 25).
As to Claim 20, the combination of Ishii, Seo, Ordal, and Tropf teaches the image sensor of claim 17. Seo, as applied to claim 17, further teaches wherein the second conductive film has a greater step coverage than the first conductive film (lateral thickness of 29p greater than that of 25 in Seo Fig 17).
Conclusion
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/Corbyn D Mellinger/Examiner, Art Unit 2899
/ZANDRA V SMITH/Supervisory Patent Examiner, Art Unit 2899
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