PURPOSE: To economically form a uniform fine circuit having high dimensional accuracy by adding glycerol to an aq. soln. contg. I2 and an iodide to prepare a soln. having a specified viscosity and by chemically etching a thin Au film coated with a photoresist with the prepd. soln.
CONSTITUTION: A thin Au film formed on a substrate is coated with a photoresist and chemically etched to form a fine circuit. The chemical etching is carried out with an aq. soln. contg. I2, an iodide such as KI or NH4I and alcohol after the viscosity is adjusted to 2.0W15.0P by adding glycerol. The etching soln. has low flowability and reduces the etching rate in the gap between the resist and substrate, so side etching is controlled and unevenness of side etching in the substrate is reduced. Thus, the thin Au film is uniformly and finely patterned with high dimensional accuracy with an inexpensive device and low-cost chemicals.
TSUCHIYA MASATOSHI
HANAZONO MASANOBU
