Apparatus for forming an aluminum interconnect structure on an integrated circuit chip

Claim 1

Apparatus for forming an aluminum interconnect structure on a substrate which structure is formed of an aluminum layer having a hard barrier aluminum oxide layer on the surface thereof, and a resist pattern to define the interconnect structure, said apparatus comprising: a chamber having a pedestal to receive and hold said substrate in an etchant-electrolyte solution; an anode in said chamber to make electrical contact with said substrate; a cathode in said chamber above said pedestal; said chamber being provided with an etchant-electrolyte solution supply port to supply said chamber with said solution to etch said aluminum oxide layer so as to expose portions of said aluminum layer; supply means coupled to said supply port to continuously supply said solution thereto; voltage means coupled to said cathode and anode to supply voltages thereto at a finite time after such substrate has resided in said solution so as to anodize said exposed portions while said solution is being continuously supplied thereto; said cathode having a planar surface to reside in parallel with said substrate and said anode extending through said cathode to make contact with said substrate; a shield around said anode; and nitrogen means coupled to said shield to supply nitrogen under pressure between said shield and said anode.