| 摘要 |
PURPOSE:To prevent the disconnection of conductive wiring by forming the opening section of the insulating film with a tapered shape with no stepped difference to a PSG film section. CONSTITUTION:An SiO2 film 5 with 6,000Angstrom thickness and a PSG film 6 with 2,000Angstrom thickness are formed onto a substrate in succession, and the PSG film 6 is selectively removed at first while using a resist pattern 7 as a mask. The SiO2 film 5 is removed by using an aqueous solution containing 6% fluoric acid and 30% ammonium fluoride. The etching rate of the SiO2 film 5 is experimentally measured previously and etching time is calculated beforehand at that time, and the siO2 film 5 is left only by approximately 500Angstrom . A resist is exfoliated, and the PSG film remaining on the surface except a window section and the SiO2 film 5 left thinly are removed by using an etching liquid of the PSG film 6 again. The PSG film 6 is also removed completely from the upper section of the SiO2 film 5 except the window section if etching is completed at a point of time when the SiO2 film 5 left thinly is precisely removed completely because the etching rate of the PSG film 6 is several times as fast as the SiO2 film 5. The tapered shape of a gentle section up to an upper edge from a lower edge of the opening window section is formed through above-mentioned processes. |
