Design of a passive micro-mechanism chuck to minimize the effect of backside particles on semiconductor wafer planarity

摘要

There are a number of factors affecting semiconductor wafer planarity, namely intrinsic factors such as warp, bow and non-linear thickness variation; and extrinsic factors such as backside particles and chuck flatness. Of these non-planarity causing factors, backside particles are the most detrimental as they affect a large portion of the wafer real estate by causing out-of-plane distortion when they get lodged between the wafer and the wafer chuck. Conventional pin type and groove type chucks correct for the non-planarity causing intrinsic factors sufficiently well but do not adequately address the extrinsic factors, especially that of backside particles. Previously, we introduced a chuck called the compliant pin chuck that can minimize the effect of backside particles. This chuck has micro-mechanism pins that react to the presence of particles in ways that eliminate the non-planarity introduced otherwise. In this paper, we discuss some key features related to the design of the compliant pin chuck.