| 摘要 |
PURPOSE:To etch a film selectively while providing a proper taper to the film by using a mask of a polymethyl isopropynyl ketone (PMIPK) resist, keeping a wafer at a prescribed temp., and carrying out plasma etching by usig a mixed gas of CF4+O2. CONSTITUTION:The relation between the temp. of a wafer and the etching speeds of a plasma CVD (PCVD) Si3N4 film and said PMIPK resist in isotropic plasma etching using a mixed gas of CF4+O2 (4%) is shown by the diagram. Accordingly, when the PCVD-Si3N4 film is plasma etched at 85-150 deg.C temp. of the wafer, e.g., at 100 deg.C, the opening is gently tapered. As a result, when the 2nd layer Al wiring 13 is formed on the PCVD-Si3N4 film 14 having the opening, step coverage at the opening edge has a very favorable shape. In the figure 10 is a wafer substrate, 11 is a diffusion region, and 15 is a PMIPK resist. |
