New Aqueous-­‐Processable “KPR-­‐Type” Photoresist for High Definition Etching and Electroforming

June 2005

Diethard Kapp-Schwoerer, Dr. Kurt Meier, and Charles Gantner,
HTP HiTech Photopolymere AG, Basel, Switzerland

Liquid resists continue to play an important role in the production of chemically-milled parts. In PCM production, the use of liquid photoresist calls for the capability to resolve openings cleanly down to 25 µm after the image transfer process using non-collimated exposure equip­ment. As discussed in the article “Liquid Resists for PCM” (The PCMI Journal, Issue No. 92), liquid resist, unlike dry film, can meet this requirement in a standard production environment. A growing number of electroforming applica­tions, especially parts produced with the overgrowth method, require the resist to resolve developed openings down to 5 µm. In the past, this requirement could be achieved only by rather costly photoresists used in microelec­tronics, where most of these resist have to be developed with organic solvents. At the 2004 PCM! Fall Conference, HTP HiTech Photopolymere AG introduced a new type of fully-aqueous processable resist for high­-definition etching and electroforming.