Method of preventing aluminum sputtering during oxide via etching
OwnerGuy Blalock, David S. Beckerinventors
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Abstract
In a double metal process for forming conductive contacts to integrated circuit structures, a method for preventing the sputtering of non-conductive aluminum compounds onto via sidewalls during the anisotropic oxide etch. A layer of nitride is deposited atop aluminum buried first metal pads before deposited of the silicon dioxide layer. A selective anisotropic oxide etch which selectively stops on the nitride is used to form the via through the oxide layer. Then an isotropic low-powered dry nitride etch extends the via through the nitride to the aluminum pad without producing unwanted sputtering.
Claims12
In a double metal process for forming an electrically conductive contact to a conductive structure in a semiconductor integrated circuit, an improvement which comprises:
- forming a first metal pad;
- forming a silicon nitride (nitride) region atop said pad;
- depositing a silicon dioxide (oxide) layer atop said nitride region;
- generating a via through said oxide layer to said nitride region, said via terminating at an end situated above an interface between said nitride region and said first metal pad;
- extending said via beyond said end through said nitride region to said first metal pad;
- and
- depositing a second metal region into said via contacting said first metal pad.
Dependencies are inferred from the claim text.