| 摘要 |
PURPOSE:To control the thickness of a silicon diaphragm accurately and to carry out stable mass production, by forming an ion implanted layer of oxygen or nitrogen in a silicon substrate, and stopping etching. CONSTITUTION:Ions of oxygen or nitrogen are implanted in a silicon substrate 21, and a silicon dioxide layer or a silicon nitride layer 22 is formed. A single crystal silicon thin film 23 is epitaxially grown. A resistor region 24 is formed by diffusion or ion implantation. A protecting film 25 of silicon nitride and the like is formed. The silicon substrate is etched by etchant (EDP liquid) comprising ethylene diamine, pyrocatechol and water. When the EDP liquid is used, the etching speed of the silicon dioxide or the silicon nitride is very slow. The etching is stopped when the layer 22 is reached. The protecting film 25 and the layer 22 are removed, and an insulating film 26 and an electrode 27 are formed. The thickness of a silicon diaphragm is equal to the thickness of the single crystal silicon thin film. The control can be carried out accurately. |
