Patent ID: 8901000
Filing Date: 2014-12-02
Classification: C09K,H01L,Y02E,Y10T

Abstract:
1. An aqueous acidic solution comprising: 2-50% hydrofluoric acid; nitric acid; and at least one polymeric surface active anionic polyether selected from the group consisting of linear and branched surface active anionic polyether copolymers, wherein said solution provides pits, more than 50% of said pits having a depth in the range of from 0.1 to 15 μm and a diameter in the range of from 0.1 to 15 μm, on a surface of both single crystal and polycrystal silicon substrates when said solution is contacted with said surface for 1 to 10 minutes at a temperature of from 0 to 50° C.