In producing an electret element having piezoelectric properties by subjecting a vinylidene cyanide copolymer to a polarization treatment, the copolymer is heat-treated at a temperature below the glass transition temperature thereof prior to or simultaneously with the polarization treatment to thereby increase the longitudinal piezoelectric effect (Kt).

A gas is introduced into a vacuum chamber after the vacuum chamber is evacuated, and a plasma is generated within at least part of the vacuum chamber. The specimen surface is exposed to the plasma so that the surface is treated. A plurality of different gases, such as SF6, N2, and the like, are used as the gas being introduced. The quantity of the gas is changed during the surface treatment. A con...

PURPOSE:To improve the uniformity of treating a wafer by supplying gases of equal speeds and equal amounts to the surface of the wafer placed on a table from opposed electrodes. CONSTITUTION:Gas from a gas supply unit is supplied to a gas passage 11, sequentially passeed through the first vacant chamber 42 and the second vacant chamber 43 to a discharge space 40, i.e., the surface of a wafer 50. I...

PURPOSE:To obtain a high positioning accuracy and the stability by a method wherein the friction coefficient on a guide surface of a theta table is made variable at the time of fixing and pivoting by utilizing the levitation of the table due to compressed air and vacuum chuck. CONSTITUTION:When the compressed air is introduced 13, an air film is produced between the theta table 12 and a base 11 an...

In a LOCOS process, depressions are formed in a semiconductor body, and are filled by means of oxidation. The bottom and side walls of the depressions are coated with a double layer including an oxide and an oxidation-resistant material. This double layer is removed from the bottom of the depression and under-etching below the sidewalls under the oxidation-resistant layer is carried out to form ca...