Process for the provision of metallized holes in dielectric substrates comprising interconnected thin film conductive and/or resistive paths

摘要

There is described a process for the provision of metallized holes in dielectric substrates comprising conductive (2) and/or resistive paths (3) belonging to hybrid circuits in thin film for microwave applications. The process comprises the steps of deposition of overlying layers of TaN (5), Ti (6) and Pd (7) on the front side, photomasking and deposition of gold (9) along predetermined paths, removal of TaN (5), Ti (6) and Pd (7) outside said paths (2,3), photoengraving of gold (9), Pd (7) and Ti (6) in correspondence of resistors (3), drilling in metal-free areas, vacuum sputtering of Ti (6') and Pd (7') on the front & back sides, deposition of negative photoresist (10) on the front side, photomasking of circular areas overlying the holes and overlying in part the conductive paths, development and galvanic growth of gold (11), elimination of the residual photoresist (10), selective chemical etching to eliminate the Pd (7') and Ti (6') in excess.