Positive Dry Film Photoresist for Fine Line Circuitry

Positive Dry Film Photoresist for Fine Line Circuitry

Summer 1986

The printed circuit (rigid and flexible), hybrid microcircuits, and photochemical machining industries in the past few years have been pushed harder and harder for fine line and space geometries. The means of achieving these have been limited to liquid negative or positive resists or negative dry films.

Liquid resists can be applied by means of spin coating, roller coating, dip coating, or spray coating. Loss of material or solvent loss can make this an expensive, as well as a difficult, process to control. Also required for this process is some form of a dryer to remove solvents and cure the resist prior to exposure.

Leo Croucher, 3M Company