Advantages of BARC and photoresist matching for 193-nm photosensitive BARC applications

As the semiconductor industry approaches smaller and smaller features, applications that previously used top antireflective coatings have now begun using developer-soluble bottom anti-reflective coatings (BARCs). However, there are several drawbacks to a wholly developer-soluble system, mainly because many of these systems exhibit isotropic development, which makes through-pitch and topography performance unsatisfactory. To solve this problem, we have developed several photosensitive BARC (PS BARC) systems that achieve anisotropic development. One issue with the PS BARC, as with traditional dry BARCs, is resist compatibility. This effect is compounded with the photosensitive nature of our materials. The acid diffusion and quenching nature of the resists has been shown to have a significant effect on the performance of the acid-sensitive PS BARC. Some resists contain a highly diffusive acid that travels to the PS BARC during the post-exposure bake and aids in clearance. Others show the opposite effect, and the same PS BARC formulation is not able to clear completely. To address the lack of compatibility and to further improve the PS BARC, we have developed a solution that properly matches PS BARC and photoresist performance.