Silicon waste-slice surface metal removal and noblemetal silver-platinum-gold recovery method

Abstract

The invention discloses the method of wiping off the exterior metal of the silicon abandoned piece and reclaiming the noble metal platinum. The semiconductor parts of an apparatus and the semiconductor integrate circuit abandoned silicon piece are dipped in the hydrochloric acid or the dilute vitriol to wipe off the metal alive than the hydrogen, the nitric acid is used to melt the cooper or the silver on the silicon piece, the combination of thick hydrochloric acid and the thick nitric acid is used to melt the gold and the platinum on the surface of the silicon piece, then the combination of the hydrofluoric acid and the nitric acid is used to melt the metal silicon material on the surface of the silicon piece, the material silicon piece is gained with the cleaning, the drying or the setting off. The metal alive than the hydrogen is added in the said silver nitrate solution to gain the silver by the permutation, the aqua regia containing the gold and the platinum is heated or is added the alkali to get rid of the excessive hydrochloric acid and the nitric acid, the copper is added in the residual solution to gain the gold or the platinum by the permutation. The invention can wipe off the metal impurity and the metal silicon material on the surface of the abandoned silicon piece effectively, the disposed silicon piece can be used for the material of the sun energy silicon single crystal, the solar cell silicon piece can be gained by the more process, the noble metal is reclaimed, so it is useful for circle utilize of the resource.

Description

technical field

[0001] The invention relates to a method for removing metal on the surface of silicon waste sheets and recovering precious metal silver and platinum Background technique

[0002] In the semiconductor discrete device (referred to as semiconductor device) and semiconductor integrated circuit industries, there will be various waste silicon wafers caused by device failure due to various reasons, and some of the silicon wafers have been deposited on the surface of metal aluminum, copper, silver, Platinum, gold, etc. When recycling these waste silicon wafers, the metal on the surface of these silicon wafers must be removed first, otherwise, these silicon wafers will be contaminated by metal in the subsequent processing process, which will seriously affect quality of silicon wafers. On the other hand, the precious metal silver, platinum, and gold resources on the surface of silicon wafers are very precious and must be recycled. Contents of the invention

[0003] ...