| 摘要 |
PURPOSE:To prevent the generation of distortion stress, to prevent the lateral intrusion of an oxide film, and to enhance yield rate, by providing a film such as an oxide film or a mixture of the oxide film and a nitride film which does not completely block O2 by self-alignment at the edge of an Si3N4 film and performing oxidation. CONSTITUTION:SiO2 2' and Si3N4 3' having a width W are provided on an Si substrate 1, and a hole 4 is vertically provided by reactive sputter etching. When SiO2 5 is deposited on all the surface and a film thickness dox is removed by the reactive sputter etching, SiO2 5' having a height (h) and a width de is remained by the self-alignment at the edge of the film 3'. Then thermal oxidation is performed, and the substrate 1 is oxidized to a depth dB, and SiO2 6 is formed beneath SiO2 5' so that dA<dB. SiO2 having a width xe intrudes in the edge of Si3N4 3', but its amount it very small. Therefore, the difference between the size W' of the active layer and the width W' of the Si3N4 mask 3' can be reduced, the defects in the selective oxidation can be removed, and the highly precised devices can be obtained. |
