THICK-FILM POSITIVE PHOTORESIST - DEVELOPMENT AND RESOLUTION ENHANCEMENT TECHNIQUE

The development of a positive, thick film photoresist consisting of a diazonaphthoquinone sensitizer and a novolac resin is described which has the capability of meeting a wide range of thick film requirements necessary for magnetic recording head fabrication. This photoresist sy stem can coat 4-15-mu m-thick films over various types of topography o n a variety of different metal and dielectric surfaces (copper, Permal loy, and alumina). Moreover, this resist is compatible with copper? pe rmally, and gold plating baths as well as different metal etchants. Th e photoresist can be used to produce images with wall profiles greater than 80 degrees with a resolution capability approaching 2 mu m lines and spaces in a 7.5-mu m-thick film. Process latitude is demonstrated over a wide range of exposure doses and focus positions. Enhancement of thick film photoresist resolution has been achieved using a method which involves the treatment of photoresist films with dilute surfacta nt solutions. A number of factors have been found to effect the outcom e of this method including the surfactant structure send concentration , the method and period of application, and the order of processing st eps. Under proper conditions significant enhancement of photoresist co ntrast is observed which is accompanied by improvement of photoresist image profile and resolution. The method is particularly useful in ele ctroplating applications. (C) 1995 American Vacuum Society.