| 摘要 |
PURPOSE:To compose an ideal T-shaped gate in a semiconductor element by forming an overlay electrode with two types of insulating films having sufficiently different etching rates with an etchant, and then removing the insulating layer of upper layer with the etchant. CONSTITUTION:A nitride film (Si3N4) of 1000Angstrom and an oxide film (SiO2) of 2000Angstrom are, for example, deposited sequentially in this order on the main flat surface of a wafer formed with a gate. Then, with PR as a mask a gate window is opened by dry etching with CF4. After the entire surface is then covered with SWi-Ti-Pt-Au as a gate electrode metal, it is etched in an overlay structure. Then, the oxide film is etched with buffer solution which contains, for example, fluoric acid: ammonium fluoride = 1:6. Since the nitride film is not almost etched with the etchant at this time, a sectional area after etching becomes as shown in (d).
|
