| 摘要 |
PURPOSE:To prevent unnecessary erosion of molybdenum and to obtain a fine electrode patter, by etching molybdenum by adding a prescribed amount of water to an etching liquid which is a mixture of nitric acid and phosphoric acid. CONSTITUTION:For example, 5-10% in volume of water is added to a molybdenum etching liquid containing 5-15% in volume of nitric acid and 85-95% in volume of phosphoric acid. By setting this etching liquid to a temperature between 20 and 30 deg.C, a molybdenum layer attached onto a semiconductor wafer is etched. The relation-ship between volume of the water added to this etching liquid and amount of etching is to become as depicted in the chart. As it is noticeable in the chart, amount of etching is large when 5-10% in volume of water is added to the molybdenum etching liquid, and the amount of etching becomes rapidly decreased when more water is added. And therefore, if the semiconductor wafer is washed at the time when the etching is required to be stopped, it is possible to stop the etching of molybdenum with simplicity and, besides, it can be easily controlled. |
