Patent ID: 7084098

Claim:
A method for improving adhesion of a polyimide surface by applying the brown oxide pretreatment composition to a brown oxide process, comprising the steps of: a) treating a printed circuit board with a brown oxide pretreatment composition for cleaning a copper surface and improving adhesion of a polyimide surface; b) water-washing the printed circuit board of a); c) pre-dipping the printed circuit board of b); d) forming a conversion coating on the printed circuit board of c); e) water-washing the printed circuit board of d); and f) drying the printed circuit board of e); wherein the brown oxide pretreatment composition for cleaning a copper surface and improving adhesion of a polyimide surface used in step a) comprises: 5–15 g/L of a hydroxylamine: 190–210 g/L of a hydroxide compound: at least one additive selected from 3–6 g/L of a cleaner adjuvant, 0.1–5 g/L of an antifoaming agent and 1–10 g/L of a precipitation inhibitor; and the balance of water.