Patent ID: 7419769
Filing Date: 2008-09-02
Classification: G03F,Y10S

Abstract:
1. A method of forming bumps, the method comprising the steps of: applying a negative photoresist composition on a substrate of an electronic part to thereby form a resist film as a coating; irradiating the resist film with active light or radiant ray through a mask having a predetermined pattern; developing the exposed resist film; and plating portions from which the resist film has been removed; wherein the negative photoresist composition for the formation of thick films having a thickness of from about 5 μm to about 40 μm, comprising relative to the total 100 parts by weight of the following components (A) through (D) combined: (A) a novolak resin in the range of about 50 to about 95 parts by weight; (B) a plasticizer in the range of about 5 to about 30 parts by weight selected from the group consisting of: (C) a crosslinking agent in the range of about 1 to 30 parts by weight; and (D) an acid generator in the range of about 0.01 to about 5 parts by weight.