Application of two-fluid nozzles for advanced photomask cleaning process cleaning process

摘要

Damage to minute features of 45nm-node device masks occurred during megasonic cleaning. Since we were obliged to weaken the mechanical effect of megasonics in order to prevent the collapse of minute features, we could not obtain acceptable cleaning results.In order to manage the minute features, there is a need to develop a new mechanical cleaning method that causes less damage, but does not compromise the ability to remove particles. Cleaning using a two-fluid nozzle is a promising candidate.We investigated the two-fluid nozzle and compared it with megasonic cleaning, and we confirmed that the two-fluid nozzle achieved acceptable cleaning results without damaging 45nm-node device masks. Furthermore, for 32nm-node device masks, we have improved the two-fluid nozzle in terms of the cleaning energy distribution.