Patent ID: 7413965

Claim:
A method of manufacturing a thin-film circuit substrate, comprising the steps of: (a) gouging a surface of a circuit substrate in advance in a depth which is at least approximately equal to or slightly larger than a finally finished thickness of the circuit substrate, without penetrating the substrate, to form a section to be formed therein a penetrating section; (b) providing a protecting adhesive tape to adhere to the surface of the circuit substrate subject to the gouging step, before a backing surface of the circuit substrate is ground; (c) grinding the backing surface of the circuit substrate in such a thickness that the section subjected to the gouging step in advanced would not penetrate through the substrate; (d) dry etching entirely the backing surface of the circuit substrate, while the protecting adhesive tape adheres to the circuit substrate, after completion of the grinding step for the backing surface of the circuit substrate; and (e) making the section subjected to the gouging step on the surface of the circuit substrate to penetrate, by the dry etching, thereby forming the penetrating structure section, wherein the protecting adhesive tape is constituted of a radiolucent film-like support and has such heat resistance that the withstands can withstand at least increase in substrate temperature in the dry etching, wherein, in the step of gouging the surface of the circuit substrate, the gouging is performed by a laser beam or plasma irradiation, and wherein, in the step of adhering the protecting adhesive tape to the surface of the circuit substrate, the adhering is performed in an atmosphere having at least a reduced pressure lower than the atmospheric pressure in the air or in an atmosphere of a reduced-pressure state at least approximately the same as an atmosphere in the dry etching.