JPS6484732A - Vacuum retention device for semiconductor element - Google Patents

Abstract

PURPOSE:To prevent the jumping of a semiconductor element from a vacuum suction part when a vacuum is discharged, by arranging a delay means to discharge negative pressure gradually in the operations for opening and closing negative pressure toward the vacuum suction part. CONSTITUTION:At a vacuum retention device of a semiconductor element equipped with a vacuum suction part 3 which sticks semiconductor element 4 by vacuum suction as well as opening and closing means 10 to open and close negative pressure toward the vacuum suction part 3, a delay means to discharge negative pressure gradually is arranged in the foregoing means 10 for opening and closing negative pressure. The foregoing delay means, for example, is composed of a plurality of solenoid valves 10a-10c which are arranged in parallel so as to open and close negative pressure toward the vacuum suction part 3 and a control means 11 which controls in sequence the solenoid valves 10a-10c. When a vacuum is discharged, first of all, the control means allows the solenoid valve 10a to be closed and the circuit of the solenoid valve 10a to be opened and then, the amount of air leakage is adjusted by speed controllers 2. Then after a while, the solenoid valve 10b is closed. Finally, the foregoing delay means permits the solenoid valve 10c to be closed and the whole solenoid valves 10a-10c to be opened and thus, the pressure of all the circuits is returned to atmospheric one to discharge vacuum retention.