DISSOLUTION RATE PROPERTIES OF 3-COMPONENT DEEP-ULTRAVIOLET POSITIVE PHOTORESISTS

This article describes the optical and dissolution properties of Shipley three-component positive deep-ultraviolet (DUV) resists. These properties are optimized to provide higher resolution resists. These resists have higher B values than diazonaphthoquinone-novolak (DQN) resists, but because of chemical amplification, their C values are 200 times smaller. Due to the higher B values of these resists, resolution can only be improved through increased dissolution selectivity. Through increased blocking, the dissolution selectivity can be as high 16 000, a value that is 10 times that of DQN resists. However, these high selectivities have practical limitations, due to increased tendency to cap, and slower photospeed. A simple equation is derived for the dissolution rate as a function of extent conversion. The catalytic chain length can be extracted from these simulations, and, under the processing conditions described in this study, is shown to be in the range of 56-78 for all the resists studied. Using experimentally derived optical and dissolution parameters, the lithographic imaging of these resists can be modeled using PROLITH/2 (a product of Finle Technologies, Inc.) lithographic modeling software. With some assumptions, reasonable agreement between the modeled and real images are seen. Finally, a high-resolution DUV positive resist, Megaposit(R) XP-3036, is described that has linearity to 0.275 mum and an E(s) of 86 mJ/cm2.