A method for preparing high power thyristor core

Abstract

The invention relates to a manufacture method of large-powered thyristor die, belonging to semiconductor manufacture technical filed. The method firstly puts silicon slice, silicon bonded aluminium foil containing silicon and molybdenum slice into die arrangement according to their widthes, then sending die arrangement into sintering furnace whose pressure is changed to 2x10-2)Pa and temperature remaining for a while, then slowly decreasing to 480 DEG C when heating is stopped and continually decreasing below 400 DEG C, when the temperature decreases to 250 DEG C stop and decreasing the temperature to normal one, acquiring large-powered thyristor die. The invention uses silicon bonded aluminium foil to make silicon and molybdenum joint together, which can decrease melting point of silicon bonded aluminium foil, as well as increases liquidity and of solder, and strengthen capability of diffusion and penetration between solder and silicon slice and molybdenum, decreasing thermal stress of silicon, aluminum and molybdenum, and increasing rate of finished products of thyristor die by more than 10%.

Description

technical field [0001] The invention relates to a method for preparing a high-power thyristor tube core, and belongs to the technical field of semiconductor device manufacturing. Background technique [0002] In the production of high-power thyristors, silicon wafers need to be sintered with molybdenum wafers after a P-type impurity diffusion, oxidation, photolithography, and N-type impurity diffusion for the second time, and then become a thyristor core after grinding and corrosion protection. The final sintering process is the key process to make a good thyristor tube core. [0003] The existing method of producing thyristor tube core is to place a piece of high-purity aluminum foil between the diffused and photoetched silicon wafer and the molybdenum wafer, and then heat it to about 700°C for sintering under vacuum to make the silicon wafer and the molybdenum wafer The sheets are sintered together. The disadvantage of the existing method is that high-purity aluminum has...

AI Technical Summary

Problems solved by technology

The disadvantage of the existing method is that high-purity aluminum has high fluidity at high temperature, and it is easy to combine with silicon to form an aluminum-silicon alloy during the heating process, that is, part of the silicon wafer is "eaten" by the aluminum, so that the silicon in the finally formed tube core There is no aluminum between the molybdenum sheet and the molybdenum sheet, or a cavity is formed in the middle of the finally formed die, which makes the die completely waste, or the thermal resistance of the die becomes larger, reducing the capacity of the device

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