Prevent passivation from keyhole damage and resist extrusion by a crosslinking mechanism

Abstract

A new method of preventing passivation keyhole damage and resist extrusion by a resist crosslinking mechanism is described. Semiconductor device structures are formed in and on a semiconductor substrate and covered by an insulating layer. Metal lines are formed overlying the insulating layer wherein there is a gap between two of the metal lines. A passivation layer is deposited overlying the metal lines. A negative tone photoresist material is coated over the passivation layer. The photoresist is exposed to light through a mask wherein the mask is clear overlying the metal lines in an active area and wherein the mask is opaque overlying a metal line in a bonding pad area where a bonding pad is to be formed. The portion of the negative tone photoresist underlying the clear mask is exposed to light whereby crosslinks are formed within the exposed photoresist and wherein the portion of the photoresist underlying the opaque mask is unexposed. The photoresist is developed wherein the unexposed photoresist is removed leaving the exposed photoresist as an etching mask. The passivation layer is etched away where it is not covered by the etching mask where the bonding pad is to be formed wherein the crosslinked photoresist protects the underlying passivation layer from etching damage.