Integration process for Al pad

摘要

A new method is provided for creating an aluminum pad on the surface of a semiconductor substrate. A passivation layer is deposited over the surface of the substrate; a layer of TaN is deposited over the passivation layer. A masked layer of aluminum is next deposited; this layer of aluminum is patterned such that the surface of the barrier layer that aligns with the alignment marker remains free of aluminum. Under the first embodiment of the invention, the exposed surface of the layer of TaN is etched to reduce the thickness of the layer of TaN to the point where the alignment marker is visible. Under the second embodiment of the invention, the exposed surface of the layer of TaN is oxidized to form a layer of Ta2O5 over this surface; this layer of Ta2O5 is transparent making the alignment marker visible. For both embodiments of the invention the surface area of the deposited aluminum can be roughened in order to enhance connect reliability for applications where the aluminum pad is used for metal interconnects.