Wafer drying system

Abstract

The present disclosure is directed to a wafer drying system and method that detects airborne molecular contaminants in a drying gas as a feedback parameter for a single wafer or multi-wafer drying process. For example, the system comprises a wafer drying station configured to dispense a drying gas over one or more wafers to dry the one or more wafers, a valve configured to divert the drying gas to a first portion and a second portion, and an exhaust line configured to exhaust the first portion of the drying gas. The system further comprises a detector configured to receive the second portion of the drying gas and to determine a real time property of the second portion of the drying gas, and a control unit configured to control a feedback operation of the wafer drying station based on the real time property of the second portion of the drying gas.

What is claimed is: 
     
         1 . A method of drying wafers, comprising:
 dispensing, in a wafer drying station, a drying gas over one or more wafers;   diverting a first portion of the drying gas to an exhaust line and a second portion of the drying gas to a detector;   exhausting, via the exhaust line, the first portion of the drying gas from the wafer drying station;   collecting the second portion of the drying gas to determine a real time property of the second portion of the drying gas; and   controlling a feedback operation of the wafer drying station based on the real time property of the second portion of the drying gas.   
     
     
         2 . The method of  claim 1 , further comprising measuring a concentration of a contaminant in the second portion of the drying gas based on the real time property of the second portion of the drying gas received from the detector. 
     
     
         3 . The method of  claim 2 , further comprising comparing the concentration of the contamination to a baseline value. 
     
     
         4 . The method of  claim 3 , further comprising:
 in response to the concentration being equal to or less than the baseline value, removing the one or more wafers from the wafer drying station; and   in response to the concentration being greater than the baseline value, rinsing the one or more wafers with deionized water and drying the one or more wafers.   
     
     
         5 . The method of  claim 2 , wherein measuring the concentration of the contaminant comprises measuring volatile organic compounds, amines, inorganic acids, acetone, sulfur dioxide, isopropyl alcohol, water vapors, or combinations thereof. 
     
     
         6 . The method of  claim 1 , wherein dispensing the drying gas comprises dispensing an inert gas or clean dry air. 
     
     
         7 . The method of  claim 6 , wherein dispensing the inert gas comprises dispensing nitrogen, argon, or helium. 
     
     
         8 . The method of  claim 1 , further comprising dispensing deionized water over the one or more wafers. 
     
     
         9 . A method, comprising:
 dispensing a drying gas over a wafer;   analyzing the drying gas to determine a concentration of a contaminant in the drying gas;   performing a removal operation on the wafer in response to the concentration of the contaminant being equal to or less than a baseline; and   performing a rework operation on the wafer in response to the concentration of the contaminant being greater than the baseline.   
     
     
         10 . The method of  claim 9 , wherein performing the rework operation comprises rinsing the wafer with deionized water. 
     
     
         11 . The method of  claim 10 , wherein performing the rework operation further comprises dispensing an inert gas over the wafer after rinsing the wafer. 
     
     
         12 . The method of  claim 9 , wherein analyzing the drying gas comprises sampling the drying gas while dispensing the drying gas over the wafer. 
     
     
         13 . The method of  claim 9 , further comprising analyzing the drying gas to determine a humidity level of the drying gas. 
     
     
         14 . The method of  claim 13 , further comprising performing a dry operation on the wafer in response to the humidity level being greater than a baseline humidity level. 
     
     
         15 . A method, comprising:
 dispensing a drying gas over a wafer;   collecting a portion of the drying gas;   analyzing the portion of the drying gas to determine a property of the drying gas;   performing a comparison between the property of the drying gas and a baseline reference; and   performing a feedback operation on the wafer based on the comparison.   
     
     
         16 . The method of  claim 15 , wherein dispensing the drying gas over the wafer comprises dispensing the drying gas while spinning the wafer. 
     
     
         17 . The method of  claim 15 , wherein collecting the portion of the drying gas comprises collecting a predetermined volume of the drying gas. 
     
     
         18 . The method of  claim 15 , wherein analyzing the portion of the drying gas comprises chemically identifying the portion of the drying gas. 
     
     
         19 . The method of  claim 15 , wherein analyzing the portion of the drying gas comprises measuring, in the portion of the drying gas, a concentration of volatile organic compounds, amines, inorganic acids, acetone, sulfur dioxide, isopropyl alcohol, water vapors, or combinations thereof. 
     
     
         20 . The method of  claim 15 , wherein performing the comparison between the property of the drying gas and the baseline reference comprises comparing a contamination level of the drying gas and a baseline contamination level.