| 摘要 |
1445659 Etching RCA CORPORATION 15 Aug 1974 [20 Aug 1973] 35976/74 Heading B6J [Also in Division H1] A selected portion of a layer 18 of silicon dioxide on a substrate 12 of silicon having a doped area 14 is etched away so as to delineate the area 14 by (a) applying a layer 20 of photoresist to the layer 18, (b) exposing and developing the layer 20 and removing it from the delineated area, (c) etching with a liquid comprising an etchant such as hydrofluoric acid and ammonium fluoride and an agent for raising the layer 20 at its interface with the layer 18 such as sulphuric acid, nitric acid, phosphoric acid or acetic acid, (d) stripping away the remaining resist. The effect is to produce a tapered formation 28. |
