The invention discloses an InP
single crystal wafer twin
polishing method. The InP
single crystal wafer twin
polishing method comprises the steps that an InP
single crystal wafer sequentially conducts rough
polishing, moderate polishing and fine polishing on a twin polishing
machine; rough polishing liquid comprises basoid
silicon dioxide suspension liquid, deionized water and
sodium dichloro cyanurate, volume ratio of the basoid
silicon dioxide suspension liquid: the deionized:
sodium dichloro cyanurate is 1:10:(1.0-1.8), and pondus hydrogenii (PH) value of the rough polishing liquid is 10-11; moderate polishing liquid comprises basoid
silicon dioxide suspension liquid, deionized water and
sodium hypochlorite, volume ratio of the basoid
silicon dioxide suspension liquid: the deionized: the
sodium hypochlorite is 1:15:(0.1-0.5), and PH value of the moderate polishing liquid is 8-9; and fine polishing liquid comprises basoid
silicon dioxide suspension liquid and deionized water, volume ratio of the basoid
silicon dioxide suspension liquid: the deionized is 1: ( 40-60), and PH value of the fine polishing liquid is 7-8. Surface quality of the InP single
crystal wafer which is obtained after polishing by adopting of the method is consistent, and the InP single
crystal wafer is
crocodile-
skin-free,
scratching-free and mist-free.