PHOTOCURABLE POLYMERS APPLIED AS ENCAPSULATING MATERIALS FOR ISFET PRODUCTION

Promising materials for semiconductor-based chemical sensors are photo curable polymers that can be applied utilizing conventional photolitho graphic processes compatible with microelectronic technology. In this work different acrylate-based polymers curable under UV irradiation ha ve been tested for their applicability as packaging materials. A mixtu re consisting of acrylate oligomer (epoxy, urethane, siloxane, polyest er), reactive monomers and suitable photoinitiator is applied to a wir e-bonded sensor chip to form a thick (100-1000 mu m) polymer layer. Af ter exposure and development, a window is opened over the gate region. Results on polymer-layer adhesion, electrical resistivity, chemical r esistance and lifetime of the encapsulated microsensors in various aqu eous solutions are presented.