SEMICONDUCTOR DEVICE ASSEMBLING METHOD Russian patent published in 2001 - IPC

FIELD: manufacture of semiconductor devices. SUBSTANCE: proposed method is designed for manufacturing semiconductor devices by flux-free soldering in the open dispensing with shielding media and may be used in assembling Schottky-barrier diodes and bipolar transistors for soldering semiconductor chips to cases by means of lead base solders. Filtering and doping element is placed on case base, then weighed amount of solder and chip are placed on top; magazine with assembled devices is mounted in hydrogen-fired traveling oven where soldering temperature of 370 C is maintained. Novelty in proposed method is that semiconductor chips with solder on collector side are locked in turned-over position within vacuum suction cup cells and aligned with contact pads of device cases; they are heated to soldering temperature in the open by pulse current passed through V-shaped electrodes which are rigidly fixed in bracket, electrically interconnected in series, and differentially arranged above each chip; as soon as solder starts melting, vacuum suction cup with chips is exposed to ultrasonic vibrations in direction parallel to soldered joint; in the process, each chip is held at pressure exerted by mass of case and bracket with electrodes. Soldering of chip surface to structures is conducted at reduced temperature, ample amount of solder is applied to surfaces being joined, and a number of chips are soldered to case simultaneously. EFFECT: enhanced reliability of semiconductor devices and productivity of assembly operations. 2 dwg