Contact surrounded by passivation and polymide and method therefor
View Patent ↗A semiconductor device has contact between the last interconnect layer and the bond pad that includes a barrier metal between the bond pad and the last interconnect layer. Both a passivation layer and a polyimide layer separate the last interconnect layer and the bond pad. The passivation layer is patterned to form a first opening to contact the last interconnect layer. The polyimide layer is also patterned to leave a second opening that is inside and thus smaller than the first opening through the passivation. The barrier layer is then deposited in contact with the last interconnect layer and bounded by the polyimide layer. The bond pad is then formed in contact with the barrier, and a wire bond is then made to the bond pad.
1. A semiconductor device, comprising:
an active circuitry region;
a contact region exclusive of the active circuitry region;
a last interconnect layer comprising aluminum over the active circuitry and the contact region;
a passivation layer over the last interconnect layer having a first opening bounded by a sidewall of the passivation layer and over the contact region;
a polyimide layer over the passivation layer having a second opening that is within the first opening so that the polyimide layer separates the second opening from the sidewall of the passivation layer;
a barrier metal layer comprising titanium tungsten over the polyimide layer and contacting the last interconnect layer in the second opening;
a bond pad metal comprising gold over the barrier metal having a contact portion outside the contact region and over the active circuitry region; and
a wire bond on the contact portion; wherein:
the barrier metal layer, the bond pad metal, and the last interconnect layer form an electrical contact; and
the polyimide layer improves durability of the contact by separating the second opening from the sidewall of the passivation layer.
2. The semiconductor device of claim 1 , wherein the polyimide layer comprises photo-imageable polyimide.
3. The semiconductor device of claim 2 , wherein polyimide layer is substantially free of polyamic acid.
4. The semiconductor device of claim 3 , wherein the passivation layer comprises nitride.
5. The semiconductor device of claim 4 , wherein the sidewall of the passivation layer is separated from the bond metal by at least one micron of polyimide.