| 摘要 |
PURPOSE:To reduce the quantity of slush production at the time of disposal of waste liquid by a method wherein a substance whose ratio of mixture of hydrofluoric acid, nitric acid, phosphoric acid, and water has been set at a vol% in a specific range is used as the etchant for the titled device of Si having an Mo electrode. CONSTITUTION:The range of composition of an etchant which can well keep the characteristic of inhibition of a semiconductor device such as a high-tension diode treated by etching with a solution made of hydrofluoric acid (HF), nitric acid (HNO3), and water and thereafter molded with glass is in a range shown by hatching, a range satisfying the conditios: 1) the rate of water composition is 20.5% (straight line L1) or more and 40% (straight lines L1, L2) or less at volume ratio; 2) the rate of composition of hydrofluoric acid is 1% (straight line L3) or more at volume ratio; further, 3) the rate of composition of nitric acid is larger than that of hydrofluoric acid (a straight line L4 compbines points for the equal rate of composition of both). |
