Patent ID: 9673037
Date: 2017-06-06
CPC Classifications: H01L

Claim:
1. A method for freeze drying a drying chemistry liquid filling high aspect ratio features on a wet substrate, comprising: displacing liquid in the high aspect ratio features with a liquid form of a drying chemistry by flowing the liquid form of the drying chemistry over the substrate, such that the liquid form of the drying chemistry fills at least a portion of the high aspect ratio features, wherein the drying chemistry comprises at least one of tert-butanol, dimethyl sulfoxide (DSMO), cyclohexane, acetic acid, carbon tetrachloride, isopropanol, and dimethyl carbonate, wherein the high aspect ratio features have a critical dimension (CD) of less than 40 nm and a pitch of less than 80 nm; transferring the wet substrate into a drying chamber; sealing the drying chamber; placing the wet substrate on an electrostatic chuck in the chamber; chucking the substrate to the electrostatic chuck; using the electrostatic chuck to back side cool the substrate below the freezing point of the drying chemistry to freeze the drying chemistry; reducing the pressure in the chamber to remove the frozen drying chemistry; and heating the substrate in a temperature-controlled manner to vaporize the drying chemistry without melting the drying chemistry.