Welding preparation method for semiconductor rectifier bridge

Abstract

The invention discloses a welding preparation method for a semiconductor rectifier bridge. A solder paste screen printing technique is adopted. Solder paste penetrates through mesh openings in a screen printing plate matched with a chip in dimension. The solder paste is horizontally and uniformly printed to the positions of frame convex points and a platform through a scraper. Due to the fact that the mesh openings in the screen printing plate are identical in size, the uniformity of the solder paste amount is guaranteed through screen printing to the maximum extent. A vacuum chuck mode is adopted by the chip so that crystal particles can be sucked and positioned, due to the facts that a vacuum chuck does not make contact with the surface of the chip directly, and the chip is sucked up through vacuum, the risk that a chip is stressed and cracked is avoided, and meanwhile accurate positioning of the chip is effectively guaranteed.

Description

technical field [0001] The invention relates to a welding preparation method for a semiconductor rectifier bridge. Background technique [0002] At present, the welding preparation method of the semiconductor rectifier bridge is mainly to place the upper and lower frames on the positioning board for positioning, use the probe on the glue machine to dip the solder paste, apply the solder paste to the solder joint position of the frame, and then use the remaining solder paste on the probe to The chip dipped in solder paste is positioned at the solder joints of the frame, and finally the frame is moved to the soldering boat, and the soldering boat after clamping the mold is put into the soldering furnace, so that the rectifier chip and the frame form an ohmic contact. [0003] At present, most of the above-mentioned production processes are used in China. The disadvantage of this method is that the uniformity of solder paste on the probe is not easy to control, and in the proc...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the uniformity of solder paste on the probe is not easy to control, and in the process of dipping the chip with the remaining solder paste on the probe, it is easy for some chips to be picked up by the probe from the solder joints of the frame. At the same time, because the probe will actually press on the chip surface, if the chip is under too much force, it will cause cracks on the chip surface, which will affect the soldering yield and the reliability after packaging is average, which cannot meet the high reliability requirements of customers.