A simple method for fabricating lines of 0.15-μ width using optical lithography

A ’’shadow deposition’’ technique using only optical lithography and conventional thin-film technology has been used to fabricate titanium lines with nominal widths of 0.15–0.30 μ on glass substrates. Each of these lines was produced by evaporating metal at an angle to a photoresist edge and utilizing the region ’’shadowed’’ from the evaporating atoms by the edge to form an in situ mask of submicron dimensions with highly correlated edges. Uniformly wide lines having tapered edges and widths less than 0.1 μ appear to be reliably attainable with this technique. It is expected that the method will be useful for making Josephson junctions and other devices employing titanium, niobium, or any other material that can be vapor deposited.