Patent ID: 7960097

Claim:
A method of etching a substrate to form one or more metallization features on the substrate, comprising: forming a bottom layer of resist on the substrate, said bottom layer of resist being sensitive to energy in a first selected range; forming a top layer of resist on said bottom layer, said top layer of resist being of a thickness greater than said bottom layer and being sensitive to energy in a second selected range; exposing a selected portion of the top layer of resist to the second selected range of energy and removing the exposed portion in the top layer to expose a portion of the bottom layer; removing the exposed portion of the bottom layer of resist to expose a portion of the substrate; etching the exposed portion of the substrate to a desired depth; forming resist undercuts in said bottom layer of resist subsequent to said etching of the exposed portion of the substrate; depositing metal on the exposed portion of the substrate and top layer of resist; and removing the top and bottom layers of resist and lifting off the metal formed on the top layer of resist to form one or more metallization features on the substrate.