| 摘要 |
PURPOSE:To reduce bird beak, by a method wherein SiO2 mask is applied and Si substrate is etched, Si3N4 and PSG are overlaid, Si3N4 is applied directly to side of element region by reactive etching, and PSG is removed and selective oxidation is perfomed. CONSTITUTION:SiO2 film 2 is selectively produced on Si substrate 1 and anisotropy etching of KOH is performed, thereby a cone-shaped element forming region 6 and a recessed insulation film forming region 7 are formed. Whole surface is coated by Si3N4 3 and PSG 9 is overlaid using CVD method thereby a region 7 is grown thicker than a region 6. If reactive ion etching is performed, the region 6 is etched a little more than the region 7 and the PSG 9 remains on the region 6 and a side portion 8. PSG is removed by HF liquid and high-temperature treating forms an isolation region 2. In this constitution, the element forming region can be formed according to design value, and isolation region with sufficient thickness and spreading can be formed between the element forming regions, thereby high density assembly can be realized. |
