Molecular Caulk: A Pore Sealing Technology for Ultra-low k Dielectrics

Much effort has been undertaken to develop high performance ultra-low k (≤ 2.2) (ULK) dielectrics to improve the interconnect speed of ultra-large scale integrated devices. Metallization issues and their poor mechanical properties have plagued the successful integration of these porous ULK dielectrics. Both of these issues are exasperated by their open pore structure. We have developed a pore sealing technology, which may allow the successful integration of these materials. We have coined the term Molecular Caulking to describe the materials that use the parylene platform for the chemical vapor deposition of these polymers. They are very unique since they can be conformally coated on demanding geometries pin-hole free at a thickness of ~10 A. We have shown that the 1 st generation material, poly(p-xylylene), is selective with respect to copper and can completely seal porous-MSQ (methyl silsesquioxane) after 30 A of deposition. This is roughly the pore diameter of this porous ULK dielectric. These materials exhibit very fast lateral growth rates and the penetration of the sealant into the ULK dielectric can be controlled. An overview will be give with respect to the Molecular Caulking technology.