Electrochemical anodization fixture for semiconductor wafers

A fixture for holding a semiconductor wafer during anodization. The fixture has a major surface with a plurality of concentric ridges on the surface for supporting a semiconductor wafer, with adjacent ridges defining concentric channels therebetween. The fixture includes electrical contact means for contacting the inward surface of the wafer. At least one channel surrounds the contact and an insulating fluid is circulated in the channel to prevent the anodizing solution from electrically shorting to the contact. Means are also supplied for maintaining a vacuum in another channel to secure the wafer against the ridges of the fixture.