| 摘要 |
PURPOSE:To protect a wiring layer and a PSG film while the rear of a semiconductor substrate is ground by a method wherein a film if formed on the wiring layer and the SPG film and a protective film is applied to the surface of the film. CONSTITUTION:A film, for instance an SW film 5 with a thickness of 4mum formed by applying SW composed of polymer as polyvinyl acetate by spin- coating, is formed on the surface of the wiring layer 3 and the PSG film 4 of a semiconductor substrate 1 and baked and then a protective film 6 is applied to the surface of the SW film 5. After the rear of the semiconductor substrate 1 on which a semiconductor element is not formed is ground, a light etching treatment is carried out with etchant prepared by mixing fluoric acid and nitric acid to remove a thermal oxide film formed on the rear in the grinding process. Then, if the protective film 6 is removed, as the adhesion strength of the SW film 5 to the protective film 6 is far stronger than that to the wiring layer 3 and the PSG film 4, the protective film 6 can be removed from the wiring layer 3 and the PSG film 4 solidly with the protective film 6, so that a chemical treatment after that can be eliminated.
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