MANUFACTURE OF SEMICONDUCTOR DEVICE

PURPOSE:To produce mask patterns for forming electrode capable of excellent lifting off by forming an overhang between a first and a second layers by a method wherein the first layer of high etching speed and the second layer of low etching speed are successively laminated on a semiconductor substrate to be isotropically etched. CONSTITUTION:A first layer 2 comprising phosphorus glass (PSG) containing phosphorous in high concentration and a second layer 3 comprising SiO2 are formed on the surface of a silicon semiconductor substrate 1. The second layer 3 is coated with a resist film 4 to form specified patterns. Then the second layer 3 is selectively removed by anisotropic etching process using reactive sputter etching process down to the depth exceeding the depth of the second layer 3. Successively the first layer 2 is removed by isotropic etching process using dilute fluoric acid as an etchant. In these etching processes, an overhang fit for lifting off is formed between the first layer 2 and the second layer 3. Later, an electrode layer 5 is formed by sputtering Al, etc. using the first and the second layers 2, 3 as masks. Finally the electrode layer 5 is formed on the substrate 1 by lifting off an Al layer 5 on the second layer 3.