| 摘要 |
PURPOSE:To make openings in Si3N4 minutely and with high density by the use of an SiO2 mask formed by forming a pattern of poly-Si on an Si3N4 film and oxidizing the same to reduce the interval of patterns. CONSTITUTION:Si3N412 and poly-Si13 are laminated on a P type Si substrate 11 and openings are made selectively in the poly-Si13. When the layer 13 is wholly converted into SiO214, the volume thereof is nearly doubled, while the width of openings is reduced. With the presence of a mask 14, Si3N4 is etched with gas plasma, whereby openings of minute width are prepared. When the mask 14 is removed by HF aqueous solution and the substrate 11 is oxidized selectively to form SiO215 in thickness nearly equal to that of Si13, the layer 15 exactly consistent with the width of the pattern of the layer 13 is obtained and thus the SiO2 film having dimensions near to the limit dimensions of patterns by photographic etching is formed, which enables attainment of high density. |
