# US 9,040,396 B2 · Manufacturing method of semiconductor device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,040,396 B2 - Document ID: US9040396B2 - Status: Granted - Kind: B2 - Application number: 14/169,837 - Filed: 2014-01-31 - Published: 2014-05-29 - Granted: 2015-05-26 - Earliest claimed: 2010-09-13 - Assignees: Semiconductor Energy Laboratory Co., Ltd. - Applicants: Semiconductor Energy Laboratory Co., Ltd. - Inventors: Masami Jintyou; Yamato Aihara; Katsuaki Tochibayashi; Toru Arakawa - Web page: https://patentgrep.com/patent/US9040396B2 ## CPC - H10D 99/00: Subject matter not provided for in other groups of this subclass - H10D 30/031: {of thin-film transistors [TFT]} - H10D 30/6704: {having supplementary regions or layers in the thin films or in the insulated bulk substrates for controlling properties of the device} - H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate} - H10D 62/405: {Orientations of crystalline planes} - H10D 62/80: characterised by the materials - H10D 64/011: {of electrodes ohmically coupled to a semiconductor} - H10D 64/62: Electrodes ohmically coupled to a semiconductor - H10P 14/22: using physical deposition, e.g. vacuum deposition or sputtering - H10P 14/2901: {Materials} - H10P 14/3426: {Oxides} - H10P 14/3434: {being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424)} - H10P 50/282: {of inorganic materials} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract An object is to provide a technique by which a semiconductor device including a high-performance and high-reliable transistor is manufactured. A protective conductive film which protects an oxide semiconductor layer when a wiring layer is formed from a conductive layer is formed between the oxide semiconductor layer and the conductive layer, and an etching process having two steps is performed. In a first etching step, an etching is performed under conditions that the protective conductive film is less etched than the conductive layer and the etching selectivity of the conductive layer to the protective conductive film is high. In a second etching step, etching is performed under conditions that the protective conductive film is more easily etched than the oxide semiconductor layer and the etching selectivity of the protective conductive film to the oxide semiconductor layer is high. ## Claims ### Claim 1 A manufacturing method of a semiconductor device comprising: forming an oxide semiconductor layer wherein the oxide semiconductor layer comprises an oxide including crystals having c-axis alignment; forming a protective conductive film over the oxide semiconductor layer; forming a conductive film over the protective conductive film; selectively etching the conductive film under a condition that a first etching selectivity of the conductive film to the protective conductive film is greater than 1, so that the protective conductive film is exposed; selectively etching the protective conductive film under a condition that a second etching selectivity of the protective conductive film to the oxide semiconductor layer is greater than 1, so that the oxide semiconductor layer is exposed; forming a gate insulating layer over the oxide semiconductor layer; and forming a gate electrode layer over the gate insulating layer to overlap with the oxide semiconductor layer. ### Claim 2 (depends on 1) The manufacturing method of a semiconductor device according to claim 1, wherein a thickness of the protective conductive film is equal to or less than a thickness of the oxide semiconductor layer. ### Claim 3 (depends on 1) The manufacturing method of a semiconductor device according to claim 1, wherein the first etching selectivity of the conductive film to the protective conductive film is greater than or equal to 4, and wherein the second etching selectivity of the protective conductive film to the oxide semiconductor layer is greater than or equal to 30. ### Claim 4 (depends on 1) The manufacturing method of a semiconductor device according to claim 1, wherein the conductive film has a stacked-layer structure including a film including aluminum as a material. ### Claim 5 (depends on 1) The manufacturing method of a semiconductor device according to claim 1, wherein the protective conductive film comprises a tungsten film. ### Claim 6 (depends on 1) The manufacturing method of a semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises a film containing indium, gallium, and zinc. ### Claim 7 A manufacturing method of a semiconductor device comprising: forming an oxide semiconductor layer wherein the oxide semiconductor layer comprises an oxide including crystals having c-axis alignment; forming a protective conductive film over the oxide semiconductor layer; forming a conductive film over the protective conductive film; selectively etching the conductive film under a condition that a first etching selectivity of the conductive film to the protective conductive film is greater than 1, so that the protective conductive film is exposed; selectively etching the protective conductive film under a condition that a second etching selectivity of the protective conductive film to the oxide semiconductor layer is greater than 1, so that the oxide semiconductor layer is exposed; and forming a gate electrode layer over the oxide semiconductor layer. ### Claim 8 (depends on 7) The manufacturing method of a semiconductor device according to claim 7, wherein a thickness of the protective conductive film is equal to or less than a thickness of the oxide semiconductor layer. ### Claim 9 (depends on 7) The manufacturing method of a semiconductor device according to claim 7, wherein the first etching selectivity of the conductive film to the protective conductive film is greater than or equal to 4, and wherein the second etching selectivity of the protective conductive film to the oxide semiconductor layer is greater than or equal to 30. ### Claim 10 (depends on 7) The manufacturing method of a semiconductor device according to claim 7, wherein the conductive film has a stacked-layer structure including a film including aluminum as a material. ### Claim 11 (depends on 7) The manufacturing method of a semiconductor device according to claim 7, wherein the protective conductive film comprises a tungsten film. ### Claim 12 (depends on 7) The manufacturing method of a semiconductor device according to claim 7, wherein the oxide semiconductor layer comprises a film containing indium, gallium, and zinc. ### Claim 13 A manufacturing method of a semiconductor device comprising: forming an oxide semiconductor layer wherein the oxide semiconductor layer comprises an oxide including crystals having c-axis alignment; forming a first conductive film over the oxide semiconductor layer; forming a second conductive film over the first conductive film; selectively etching the second conductive film under a condition that a first etching selectivity of the second conductive film to the first conductive film is greater than 1,so that the first conductive film is exposed; selectively etching the first conductive film under a condition that a second etching selectivity of the first conductive film to the oxide semiconductor layer is greater than 1, so that the oxide semiconductor layer is exposed; and forming an insulating layer and an electrode layer over the oxide semiconductor layer so that the insulating layer is interposed between the oxide semiconductor layer and the electrode layer. ### Claim 14 (depends on 13) The manufacturing method of a semiconductor device according to claim 13, wherein a thickness of the first conductive film is equal to or less than a thickness of the oxide semiconductor layer. ### Claim 15 (depends on 13) The manufacturing method of a semiconductor device according to claim 13, wherein the first etching selectivity of the second conductive film to the first conductive film is greater than or equal to 4, and wherein the second etching selectivity of the first conductive film to the oxide semiconductor layer is greater than or equal to 30. ### Claim 16 (depends on 13) The manufacturing method of a semiconductor device according to claim 13, wherein the second conductive film has a stacked-layer structure including a film including aluminum as a material. ### Claim 17 (depends on 13) The manufacturing method of a semiconductor device according to claim 13, wherein the first conductive film comprises a tungsten film. ### Claim 18 (depends on 13) The manufacturing method of a semiconductor device according to claim 13, wherein the oxide semiconductor layer comprises a film containing indium, gallium, and zinc.