# US 12,007,604 B2 · Optical dielectric planar waveguide process > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,604 B2 - Document ID: US12007604B2 - Status: Granted - Kind: B2 - Application number: 18/092,492 - Filed: 2023-01-03 - Published: 2023-05-18 - Granted: 2024-06-11 - Earliest claimed: 2018-01-25 - Assignees: POET Technologies, Inc. - Applicants: POET Technologies, Inc. - Inventors: William Ring; Miroslaw Florjanczyk; Suresh Venkatesan - Web page: https://patentgrep.com/patent/US12007604B2 ## CPC - C23C 16/308: {Oxynitrides} - G02B 6/132: by deposition of thin films - C23C 16/345: {Silicon nitride} - C23C 16/401: {containing silicon} - G02B 6/12019: {characterised by the optical interconnection to or from the AWG devices, e.g. integration or coupling with lasers or photodiodes (coupling integrated waveguide to fibre G02B6/30, to optoelectronic element G02B6/42; monolithic integration of integrated waveguides with other optical elements G02B6/12004)} - G02B 6/122: Basic optical elements, e.g. light-guiding paths - G02B 6/136: by etching - G02B 6/4272: {with mounting substrates of high thermal conductivity} - G02B 6/43: Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections - C23C 16/34: Nitrides {(C23C16/303 takes precedence)} - C23C 16/50: using electric discharges {(generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34)} - C23C 16/56: After-treatment - H01J 37/32091: {the radio frequency energy being capacitively coupled to the plasma} - H01J 2237/3321: CVD [Chemical Vapor Deposition] - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract A method for depositing silicon oxynitride film structures is provided that is used to form planar waveguides. These film structures are deposited on substrates and the combination of the substrate and the planar waveguide is used in the formation of optical interposers and subassemblies. The silicon oxynitride film structures are deposited using low thermal budget processes and hydrogen-free oxygen and hydrogen-free nitrogen precursors to produce planar waveguides that exhibit low losses for optical signals transmitted through the waveguide of 1 dB/cm or less. The silicon oxynitride film structures and substrate exhibit low stress levels of less than 20 MPa. ## Claims ### Claim 1 A method comprising depositing multiple layers of films on a substrate, wherein the multiple layers of films comprises a stack of silicon oxynitride films; and patterning the multiple layers of films to form a waveguide with a core of the waveguide comprising silicon oxynitride, wherein at least a silicon oxynitride film in the stack of silicon oxynitride films is deposited using a plasma enhanced chemical vapor deposition (PECVD) process, wherein process gases in the PECVD process comprise a silicon-containing precursor not containing hydrogen and one or more precursors for oxygen and nitrogen, and wherein the one or more precursors of oxygen and nitrogen comprise an amount of hydrogen less than 10% of the process gases. ### Claim 2 (depends on 1) A method as in claim 1, wherein the amount of hydrogen is less than 5% of the process gases. ### Claim 3 (depends on 1) A method as in claim 1, wherein the process gases comprise a hydrogen-free chemistry. ### Claim 4 (depends on 1) A method as in claim 1, wherein the process gases comprises less than 10% ammonia. ### Claim 5 (depends on 1) A method as in claim 1, wherein the one or more precursors for oxygen and nitrogen comprise at least one of a precursor for oxygen and a precursor for nitrogen, a precursor for oxygen, and a precursor for nitrogen and oxygen, or a precursor for nitrogen, and a precursor for nitrogen and oxygen. ### Claim 6 (depends on 1) A method as in claim 1, wherein ratios of process gases are configured to achieve a stoichiometry for the silicon oxynitride films that exhibits an index of refraction between 1.55 and 2.05, and wherein ratios of process gases are configured to achieve a stress level less than 25 MPa in magnitude. ### Claim 7 (depends on 1) A method as in claim 1, wherein the at least a silicon oxynitride film comprises a stress level less than 25 MPa in magnitude, or wherein the stack of silicon oxynitride films comprises a stress level less than 25 MPa in magnitude, or wherein individual silicon oxynitride films in the stack of silicon oxynitride films have a stress level less than 25 MPa in magnitude. ### Claim 8 (depends on 1) A method as in claim 1, wherein the at least a silicon oxynitride film is formed using process temperatures less than 500 C to prevent damages to the substrate. ### Claim 9 (depends on 1) A method as in claim 1, wherein the substrate comprises an interconnection layer comprising an electrical interconnection line. ### Claim 10 (depends on 1) A method as in claim 1, wherein the substrate comprises an interconnection layer formed on an electrical device, and wherein the interconnection layer comprises an electrical interconnection line electrically connected to a terminal of the electrical device. ### Claim 11 A method comprising depositing multiple layers of films on a substrate, wherein the multiple layers of films comprises a stack of silicon oxynitride films; and patterning the multiple layers of films to form a waveguide with a core of the waveguide comprising silicon oxynitride, wherein at least a silicon oxynitride film in the stack of silicon oxynitride films is deposited using a plasma enhanced chemical vapor deposition (PECVD) process, and wherein process gases in the PECVD process comprise an amount of hydrogen configured to form the at least a silicon oxynitride film having a stress level less than 25 MPa in magnitude or configured to form the at least a silicon oxynitride film using process temperatures less than 500 C to prevent damages to the substrate. ### Claim 12 (depends on 11) A method as in claim 11, wherein the amount of hydrogen is less than 10% of the process gases. ### Claim 13 (depends on 11) A method as in claim 11, wherein the process gases comprises a precursor for silicon, a precursor for nitrogen, and a precursor for oxygen, and wherein at least one of the precursor for silicon, the oxygen precursor, or the nitrogen precursor comprises a hydrogen-free chemistry. ### Claim 14 (depends on 11) A method as in claim 11, wherein the at least a silicon oxynitride film is formed using process temperatures less than 400 C to prevent damages to the substrate. ### Claim 15 (depends on 11) A method as in claim 11, wherein the substrate comprises an interconnection layer comprising an electrical interconnection line. ### Claim 16 A method comprising depositing multiple layers of films on a substrate, wherein the multiple layers of films comprises a stack of silicon oxynitride films; and patterning the multiple layers of films to form a waveguide with a core of the waveguide comprising silicon oxynitride, wherein at least a silicon oxynitride film in the stack of silicon oxynitride films is deposited using a plasma enhanced chemical vapor deposition (PECVD) process, and wherein process gases in the PECVD process comprise an amount of hydrogen configured to form the at least a silicon oxynitride film, as-deposited, having a level of optical loss of less than 1 dB/cm. ### Claim 17 (depends on 16) A method as in claim 16, wherein the amount of hydrogen is less than 10% of the process gases. ### Claim 18 (depends on 16) A method as in claim 16, wherein process gases comprise a silicon-containing precursor not containing hydrogen. ### Claim 19 (depends on 16) A method as in claim 16, wherein the waveguide is formed using process temperatures less than 500 C to prevent damages to the substrate, and wherein ratios of process gases are configured to achieve a stress level less than 25 MPa in magnitude. ### Claim 20 (depends on 16) A method as in claim 16, wherein the substrate comprises an interconnection layer formed on an electrical device, and wherein the interconnection layer comprises an electrical interconnection line electrically connected to a terminal of the electrical device.