| 摘要 |
PURPOSE:To permit etching for forming an Si groove which is minute and favorable for flattening, by providing inclinations in the upper part of the groove without making the width of the groove larger than the dimension of a mask formed on a semiconductor substrate. CONSTITUTION:After an etching mask 12 made of SiO2, Si3N4 or the like is formed on an Si substrate 11, a wet etching employing a hydrazine solution or a plasma etching employing CCl4 gas is carried out to form an etching groove having surfaces 13 left unetched and inclined from the mask ends toward the inside of the groove. Then, an SiO2 film 14 is deposited on the whole surface and etched as much as the film thickness part by employing a sputter etching method. Consequently, the thickness of the film 14 is reduced correspondingly to the film thickness in the depthwise direction. Thereby, unetched parts 15 are left having a thickness in the depthwise direction almost 0.74 time as much as the former film thickness. When an Si reactive sputter etching is carried out with the films 15 used as a mask, only the exposed bottom of a groove 16 is etched, thereby allowing a Y-shaped groove 17 to be formed. |
