We have designed and developed an aqueous base soluble polymer system with a silsequioxane (SSQ) backbone for 157nm bilayer resist applications. These base resins have absorbances as low as 0.6micrometers -1 at 157nm. The imagable polymers which contain acid-labile ester functionalities have absorbances between 2.0 and 3.0micrometers -1. The silicon content of these polymers is around 15% by weight. Therefore, our polymers can be utilized in 157nm positive bilayer resist applications with a film thickness of around 150nm. We have evaluated several resist formulations based on these polymers. These resist formulations have shown high contrast and excellent resolution.