Methods And Apparatus For MEMS Structure Release

Abstract

An apparatus may include a vessel adapted to contain an organic solvent and a dehydration apparatus coupled with the vessel. The dehydration apparatus may be adapted to remove water from the organic solvent. The apparatus may further include a water content monitor coupled to the dehydration apparatus and the vessel, in which the water content monitor is adapted to determine a water content of the organic solvent. The apparatus may further include a wafer handler adapted to transfer at least one semiconductor wafer including a MEMS device into the vessel.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a vessel adapted to contain an organic solvent;   a dehydration apparatus coupled with the vessel, the dehydration apparatus adapted to remove water from the organic solvent;   a water content monitor coupled to the dehydration apparatus and the vessel, the water content monitor adapted to determine a water content of the organic solvent; and   a wafer handler adapted to transfer at least one semiconductor wafer including a MEMS device into the vessel.   
     
     
         2 . The apparatus of  claim 1 , wherein the vessel, the dehydration apparatus, and the water content monitor are in a recirculation path of the organic solvent. 
     
     
         3 . The apparatus of  claim 1 , wherein the organic solvent is one selected from the group consisting essentially of isopropyl alcohol and methyl alcohol. 
     
     
         4 . The apparatus of  claim 1 , wherein the organic solvent is isopropyl alcohol. 
     
     
         5 . The apparatus of  claim 1 , wherein the dehydration apparatus comprises a molecular sieve. 
     
     
         6 . The apparatus of  claim 5 , wherein the molecular sieve is adapted to remove water until the water content of the organic solvent is less than about 300 parts per million. 
     
     
         7 . The apparatus of  claim 5 , wherein the molecular sieve comprises a zeolite compound. 
     
     
         8 . The apparatus of  claim 1 , wherein the dehydration apparatus comprises a dehydrator adapted to apply a chemical drying agent to the organic solvent. 
     
     
         9 . The apparatus of  claim 1 , wherein the water content monitor comprises an infrared detector adapted to measure an absorbance of infrared energy by the organic solvent. 
     
     
         10 . An apparatus, comprising:
 a reactant vessel adapted to contain a solvent, the reactant vessel comprising an outflow portion and an inflow portion;   a dehydration apparatus comprising an outflow portion and an inflow portion, wherein the outflow portion of the reactant vessel is coupled to the inflow portion of the dehydration apparatus, the dehydration apparatus adapted to remove water from the solvent; and   a water content monitor comprising an outflow portion and an inflow portion, the water content monitor adapted to determine a water content of the solvent, wherein the outflow portion and the inflow portion of the water content monitor are coupled to the inflow portion of the reactant vessel and the outflow portion of the dehydration apparatus, respectively, and wherein the reactant vessel, the dehydration apparatus, and the water content monitor form a recirculation path of the solvent.   
     
     
         11 . The apparatus of  claim 10 , further comprising a wafer cassette adapted to hold at least one semiconductor wafer including a MEMS device, and an arm adapted to move the wafer cassette into and out of the reactant vessel. 
     
     
         12 . The apparatus of  claim 10 , wherein the water content monitor is further adapted to compare the water content of the solvent to a threshold. 
     
     
         13 . The apparatus of  claim 10 , wherein the water content monitor comprises an infrared detector adapted to measure an absorbance of infrared energy by the solvent. 
     
     
         14 . The apparatus of  claim 10 , wherein the water content monitor determines the water content of the solvent periodically. 
     
     
         15 . The apparatus of  claim 10 , wherein the water content monitor determines the water content of the solvent continuously. 
     
     
         16 . The apparatus of  claim 10 , wherein the dehydration apparatus comprises a molecular sieve. 
     
     
         17 . An apparatus, comprising:
 a vessel containing a solvent;   a wafer cassette holding at least one semiconductor wafer including a MEMS device, the at least one semiconductor wafer immersed in the solvent;   a dehydration apparatus coupled with the vessel, the dehydration apparatus adapted to remove water from the solvent; and   a water content monitor coupled to the dehydration apparatus and the vessel, the water content monitor adapted to determine a water content of the solvent, wherein the vessel, the dehydration apparatus, and the water content monitor are in a recirculation path of the solvent.   
     
     
         18 . The apparatus of  claim 17 , wherein the solvent is one selected from the group consisting essentially of isopropyl alcohol and methyl alcohol. 
     
     
         19 . The apparatus of  claim 17 , wherein a recirculation of the solvent is stopped when the water content of the solvent is below a threshold. 
     
     
         20 . The apparatus of  claim 19 , wherein the threshold is about 300 parts per million.