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.