Advanced Wafer Drying Technology for 1x Node and Beyond Using Surface Modification Method

摘要

The liquid IPA dry method has until recently been used as a method to prevent pattern collapse instead of the spin dry since it is easy to use on the single wafer tools. However, it is reaching the limit of process margin since IPA surface tension is only one third that of water. We focused on the other parameter that decides the Laplace force: contact angle. When the contact angle is close to 90 degrees, the force approaches zero, which enables larger process margins for next generation structures. We call this concept of drying 'Surface Modification Method (SMM)'. Then we compared the performance of SMM to the liquid IPA dry. No collapse was found with SMM using 1x node pattern sample.