Photopatternable insulating materials

Present direct photopatternable insulating materials are only available as negative working systems. In connection with the increasing requirements for resolution capability, higher processing performance and for environmental reasons, positive working systems offer significant advantages for the future. One of the most promising systems is a formulation composed of a polybenzoxazole (PBO) precursor and a diazoquinone sensitizer. Compared with the well known novolac-based positive resists which are used for fine patterning in IC manufacturing, the annealed PBO resist incorporates both resist and dielectric properties. The present paper discusses general aspects of positive and negative mode patterning with the emphasis on positive working PBO precursors which fulfill the most important future requirements.