| 摘要 |
1311509 Etching PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 19 May 1970 [22 May 1969] 24222/70 Heading B6J A method of etching a surface comprises providing on the surface an etch resistant mask and then, either immediately, or after a period of etching, coating the exposed areas of surface and the mask with a positive photoresist, exposing and developing the resist and etching the exposed areas of the surface. The coating of photoresist fills dry gaps between the mask and the surface and may also fill any cavities formed by underetching of the mask during a first period of etching. Upon exposure and development only those areas of photoresist fitting these gaps and cavities remain. In an embodiment, Figs. 4 and 5, the mask 12 is of nickel (which has been formed by selectively etching a nickel layer with nitric acid through a photoresist 13) and the surface 11 is aluminium. An overall coating of positive photoresist 14 fills the cavities 15 and 16 formed by underetching during a first period of etching. On exposure and development of the resist only those areas in the cavities, Fig. 5, remain to protect the surface from further etching (with phosphonic acid). In a further embodiment, Figs. 8 and 9, the mask 27 and 28 is of nickel and the surface 22 is of SiO 2 . Initial etching of the nickel with nitric acid enlarges gaps 29 between the mask and the surface. These gaps are filled by the overall positive photoresist coating 30, which, when exposed and developed, remains to protect the gaps from the NH 4 F/HF etchant used to attack the SiO 2 surface. |
