A method of manufacturing a thin-film circuit substrate, containing:(a) gouging a surface of a circuit substrate in a depth at least approximately equal to a thickness of a final product of the substrate, to form a section to be formed a penetrating section;(b) providing a protecting adhesive tape to adhere to the gouged surface of the substrate, before a backing surface of the substrate is ground;(c) grinding the backing surface in such a thickness that the gouged section would not penetrate;(d) dry etching entirely the backing surface, while the tape adheres to the substrate, after completion of the grinding for the backing surface; and(e) making the gouged section of the substrate to penetrate, by the dry etching, thereby forming the penetrating structure section; and,a protecting adhesive tape usable in the method.