Abstract: A positive photoresist adhesion promoter which is provided as a thin layer between a resist such as polymethylmethacrylate for use on gallium arsenide is described. The positive photoresist adhesion promoter includes a mixture of a positive photoresist with an organic solvent. The use of the positive adhesion promoter increases the resistance of the resist such as PMMA to chemical stress during subsequent processing steps for the circuit. An alternative arrangement is to use a composition of the photoresist to be deposited as the masking layer as adhesion promoter layer and processing the adhesion promoter layer to induce cross linking in the resin component of the photoresist material to thus provide a tenacious bond between the adhesion promoter layer and the material of the substrate, such as gallium arsenide.