摘要 |
A layer of photoresist 16 having a generally flat surface is formed on a layer of PSG 15 having a projection thereon. A non-selective dry etching process using a reaction gas is effected in which a layer 16 and 15 are etched at equal rates. The etching process may be plasma etching using a mixture of a flouride compound gas and oxygen gas. Reactive sputter etching or reactive ion etching can also be used. The photoresist of layer 16 could be replaced by polyimide or liquid glass. PSG layer 15 could alternatively be a layer of polycrystal line silicon or wiring conductor. In each case, the use of a reaction gas mixture which ensures equal etching rates provides a flat surface at the finish of etching. |