Pattern Collapse and Particle Removal Forces of Interest toSemiconductor Fabrication Process

摘要

The removal of particles from silicon wafers without pattern damage during fabrication process isextremely important for increasing the yield. Various physically assisted cleaning techniques such asmegasonic cleaning, jet spray cleaning, and laser shock wave cleaning (LSC) have been introduced.However, most of tools show pattern damage [1]. One of the main challenges in next generationcleaning process is the particle removal without the pattern damage. As the feature size continues todecrease, the patterns are so fragile that it is hard to remove particles less than 50 nm without patterndamages. To accomplish the effective cleaning performance without the damage, the collapse force ofpattern and removal force of particle should be known quantitatively. In this paper, pattern collapseforces were measured for different gate stack patterns by lateral force microscope (LFM) [2]. Theparticle removal mechanism of LSC was studied to find the relationship between measured collapseforces and particle removal force by LSC which has a known applied force. Finally, particlecontaminated pattern wafers were cleaned by LSC with optimized process parameters to verify therelationship and to achieve the best particle removal performance without the pattern damage.