DETAILED ACTION
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, 3, 4, 6, 10, 18-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over “Thermo-optic tunable silicon grating coupler” by Liu et al. (2015) in view of CN 109698154 B patent publication.
Regarding claim 1, Liu teaches a method of manufacturing a semiconductor photonic device (Figs. 1, 2), comprising: providing a first substrate (SOI substrate) comprising a base layer (silicon), an insulator layer (silicon dioxide) overlying the base layer, and a surface layer (silicon layer used to form a silicon waveguide) overlying the insulator layer; forming an optical component (grating coupler on the right end of the waveguide, Fig. 1) in a first region of the surface layer of the first substrate; forming a temperature control member (titanium micro-heater) partially encircling the optical component.
Liu does not further teach using a thermal preservation layer. The ‘154 publication discloses an integrated circuit manufacturing method of a carrier layer 306 with heat reservation function, comprising removing a base layer of a first substrate (first carrier 302 of a higher thermal conductivity, Figs. 3C-3D); and depositing a thermal preservation layer (306) on the insulator layer of the first substrate (adhesive layer 305), wherein the base layer of the first substrate has a first thermal conductivity (silicon), and the thermal preservation layer has a second thermal conductivity less than the first thermal conductivity (306 may be a sapphire substrate which has a lower thermal conductivity than silicon). Adopt the carrier (306) whose thermal conductivity is lower than the bare silicon to maintain heat preservation to prevent fast heat loss. Since Liu’s invention is drawn to using a heater to thermally tune the silicon grating coupler, it would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Liu’s invention, by using a heat preservation carrier or substrate, instead of the silicon, to lower heat loss during thermal tuning, and subsequently the power requirement for the photonic IC.
Regarding claims 3, 4, Liu further teaches the optical component is disposed at a different level below that of the temperature control member (as shown in Figs. 1, 2, the silicon waveguide is formed in the silicon layer of the SOI substrate whereas the heater is formed on top of the silicon layer).
Regarding claim 6, Liu further teaches forming a heat transfer member (gold/Au pad) in the surface layer and connected to the optical component, wherein the temperature control member partially overlaps the heat transfer member (Ti acts as an adhesive layer for Au contact pad).
Regarding claim 10, Liu further teaches that the thermal preservation layer has a thickness less than a thickness of the base layer of the first substrate (a thin layer of silicon dioxide of several microns can alternately act as the thermal preservation layer, as layer 3062 in Fig. 3E).
Regarding claim 18, Liu teaches a semiconductor photonic device, comprising: an optical component (grating coupler) disposed on an insulator layer (silicon dioxide); and a temperature control member (Ti heater and isolation trenches) partially encircling the optical component from a top-view perspective. Liu teaches using an SOI substrate with a silicon base layer below the silicon dioxide insulator layer, rather than a thermal preservation layer as claimed.
The ‘154 publication discloses an integrated circuit with a carrier layer 306 with heat reservation function, comprising removing a base layer of a first substrate (first carrier 302 of a higher thermal conductivity, Figs. 3C-3D); and depositing a thermal preservation layer (306) on the insulator layer of the first substrate (adhesive layer 305), wherein the base layer of the first substrate has a first thermal conductivity (silicon), and the thermal preservation layer has a second thermal conductivity less than the first thermal conductivity (306 may be a sapphire substrate which has a lower thermal conductivity than silicon). Adopt the carrier (306) whose thermal conductivity is lower than the bare silicon to maintain heat preservation to prevent fast heat loss. Since Liu’s invention is drawn to using a heater to thermally tune the silicon grating coupler, it would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Liu’s invention, by using a heat preservation carrier or substrate and below the insulating silicon dioxide layer, instead of the silicon base layer, to lower heat loss during thermal tuning, and subsequently the power requirement for the photonic IC.
Regarding claim 19, Liu further teaches the temperature control member (the isolation trenches) and the optical component are disposed at a same vertical level.
Regarding claim 20, Liu further teaches the temperature control member (the titanium heater) is disposed over the optical component.
Claim(s) 2, 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu and the ‘154 publication as applied to claim 1 above, and further in view of U.S. PGPub 2013/0209026 A1 by Doany et al.
Regarding claim 2, Liu teaches thermally tuning the optical waveguide but uses a metal (Ti) as the heater rather than doped regions as claimed. Watts also teaches a method of using electric heater to tune waveguide (Figs. 2A, 2B), wherein electrical power can be supplied to a heater (34) through a pair of connecting members (22) located inside of an optical waveguide (14), and wherein the connecting members can be formed from monocrystalline silicon (i.e. a part of the monocrystalline silicon layer of an SOI substrate) via impurity doping, and wherein the connecting members (22) are doped with a higher level of impurity doping than the electrical heater (34), so as to provide a much lower resistivity so that the heat generation occurs primarily in the electrical heater (34) and not in the connecting members (22). This design illustrates one of the advantages of doping semiconductors to improve its conductivity, where its electrical properties can be precisely controlled, and it would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Liu’s invention, by using doping silicon surface layer (of the SOI substrate in Liu) in a second region corresponding to the location of the Ti heater to form the heater, as suggested by Watts for the same advantage.
Regarding claim 7, the heat transfer member (doped silicon) and the optical component (silicon waveguide) are formed of the same silicon surface layer.
Claim(s) 11-13, 15-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu and the ‘154 publication, and further in view of U.S. Patent 7,941,014 to Watts et al.
Regarding claim 11, Liu teaches a method of manufacturing a semiconductor photonic device, comprising: providing a silicon-on-insulator (SOI) substrate comprising a base layer (silicon substrate), an insulator layer (silicon dioxide or BOX layer) overlying the base layer, and a silicon layer (for forming the silicon waveguide) overlying the insulator layer; forming an optical coupler (grating coupler) in a first portion (right portion) of the silicon layer of the SOI substrate; forming a temperature control member (titanium heater) partially encircling the optical coupler.
Liu teaches coupling the grating coupler to an optical fiber (Fig. 2) but not forming a lens at least partially overlapping the optical coupler from a top-view perspective. Doany also teaches a method of coupling a grating coupler (130) to an external optical fiber (114), including forming a lens (132) on a surface of a substrate (110) to optically couple to the external fiber (114). See at least Figs. 1, 2 and description. The lens focusses the light from the waveguide and grating coupler to the external optical fiber, which improves coupling efficiency. It would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Liu’s invention, by etching or bonding a lens to the substrate as suggested by Doany, in a position that couples light between the external fiber and the grating coupler, for the same reason.
Liu further does not teach using a thermal preservation layer. The ‘154 publication discloses an integrated circuit manufacturing method of a carrier layer 306 with heat reservation function, comprising removing a base layer of a first substrate (first carrier 302 of a higher thermal conductivity, Figs. 3C-3D); and depositing a thermal preservation layer (306) on the insulator layer of the first substrate (adhesive layer 305), wherein the base layer of the first substrate has a first thermal conductivity (silicon), and the thermal preservation layer has a second thermal conductivity less than the first thermal conductivity (306 may be a sapphire substrate which has a lower thermal conductivity than silicon). Adopt the carrier (306) whose thermal conductivity is lower than the bare silicon to maintain heat preservation to prevent fast heat loss. Since Liu’s invention is drawn to using a heater to thermally tune the silicon grating coupler, it would have been obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to modify Liu’s invention, by using a heat preservation carrier or substrate, instead of the silicon, to lower heat loss during thermal tuning, and subsequently the power requirement for the photonic IC.
Regarding claims 12, 13, Liu further teaches forming a spacer (isolation trenches) to isolate the optical coupler from the temperature control member, wherein the spacer (the trenches) has a uniform width (Fig. 1).
Regarding claim 15, Liu further teaches the temperature control member (the isolation trenches) and the optical component are disposed at a same vertical level.
Regarding claim 16, Liu further teaches the temperature control member is, from a top-view perspective, separated from the optical coupler by a non-uniform distance (lateral separation is different due to the presence of the isolation trenches).
Regarding claim 17, Liu further teaches the temperature control member (titanium heater) is arranged along a contour around a perimeter of the optical coupler (follows the contour or shape of the grating coupler).
Allowable Subject Matter
Claims 5, 8, 9 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. Liu is the closest relevant prior art that disclose encircling the optical component or grating coupler with the temperature control member but does not further teach or fairly suggest additional layers or structure upon the tunable grating coupler device such as an isolation layer or bonding structures as well as a second substrate with a lens, when considered in view of the rest of the limitations of the claimed invention.
Claim 14 is 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. Liu is the closest relevant prior art that disclose encircling the optical component or grating coupler with the temperature control member including the spacer or isolation trenches but does not further teach or fairly suggest isolation trench may be made of or filled with the same material as the coupler and temperature controller, when considered in view of the rest of the limitations of the claimed invention.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. JP2008230573 discloses a semiconductor device having a thermal conductive insulator 131 is embedded in a removal region 130 of a substrate.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHARLIE PENG whose telephone number is (571)272-2177. The examiner can normally be reached 9AM - 6PM.
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/CHARLIE Y PENG/Primary Examiner, Art Unit 2874
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