Mesa etching process of high voltage diode silicon blocks

Abstract

The invention relates to a mesa etching process of high voltage diode silicon blocks. The mesa etching process sequentially comprises performing mixed acid preparation; placing the silicon blocks to be treated into a BE plastic film and arranging the BE film with the silicon blocks on a plastic supporting frame; performing mixed acid treatment; performing etching quantity measurement; performing first time washing; performing nitric acid etching cleaning; performing second time washing; performing third time washing; performing dewatering and drying; drying the dry air; performing assembly sintering on the silicon blocks and electrode leads. According to the mesa etching process of the high voltage diode silicon blocks, a novel mixed acid is developed and accordingly the etching speed of cutting surfaces of the silicon blocks is consistent, the difference of the etching quantity is small, and damage layers caused by cut-off are completely removed; hydrofluoric acid cleaning treatment is performed after the mixed acid treatment is performed and accordingly a few oxidation layers on the surface of chip solder are removed and the good sintering soldering of the electrode leads can be convenient; the etching treatment rate is uniform and accordingly the good mesa shapes of the silicon blocks are formed and the difference of the etching quantity is small; the reverse electric leakage of a device is small, the breakdown characteristic is hard, the surge tolerance is large, and the rate of finished products is significantly improved.

Description

technical field [0001] The invention relates to a high-voltage diode silicon block mesa corrosion process, in particular to a process method for high-voltage diode chip mesa corrosion cleaning and mesa formation. Background technique [0002] The silicon stack is cut into a silicon block by stainless steel wire supplemented with emery cutting fluid, that is, a high-voltage diode die. The surface of the silicon block has damaged layers, oxide layers, and other impurities caused by cutting. Before the silicon block and electrode leads are sintered, the mesa must be cleaned. The electrical properties of the device. Otherwise, the electrical performance of the device will be deteriorated, and the yield of the electrical test of the product will be greatly reduced. [0003] The traditional silicon block treatment process is a mixed acid etching composed of four components: nitric acid, hydrofluoric acid, sulfuric acid, and glacial acetic acid. During the silicon block etching p...

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Problems solved by technology

[0003] The traditional silicon block treatment process is a mixed acid etching composed of four components: nitric acid, hydrofluoric acid, sulfuric acid, and glacial acetic acid. During the silicon block etching process, the corrosion rate of the P surface and the N surface is unbalanced. After the treatment, the surface of the silicon block is uneven. Easy to produce gaps and inclined junctions