Manufacture of ultra-clean surfaces by selective

Abstract

A method and apparatus for removing surface impurities from a surface of a material, particularly silicon wafers, includes identifying the location of at least one impurity particle on a surface of the material and applying a liquid to the surface in the vicinity of the at least one impurity particle. The liquid is explosively evaporated to remove the surface particle as part of the evaporation of the liquid. The apparatus can include a source of humidified gas for the liquid and a laser apparatus to provide the heat for liquid evaporation.

1 . A method of reducing defect occurrence in processing of silicon wafers comprising: 
 inspecting a plurality of wafers for the presence of surface particles on a given wafer surface;    selecting from said plurality of wafers one or more wafers that have one or more surface particles that do not meet a pre-set inspection parameter and identifying a location of each of said surface particles; and    subjecting the selected wafers to a cleaning step, wherein the cleaning step includes providing a liquid in a vicinity of each detected surface particle and explosively evaporating the liquid, each detected surface particle being removed as part of the evaporation of the liquid, the selected wafers then subjected to a further manufacturing step, with or without non-selected wafers.    
   
   
       2 . The method of  claim 1 , wherein laser heat is used for the explosive evaporation.  
   
   
       3 . The method of  claim 1 , wherein a suction is applied in the vicinity of the detected surface particle during the evaporating step to help remove the detected surface particle.  
   
   
       4 . The method of  claim 1 , wherein the explosive evaporation is monitored to ensure that the detected particle is removed.  
   
   
       5 . The method of  claim 1 , wherein the liquid is provided by condensation from a gas.  
   
   
       6 . The method of  claim 1 , wherein the liquid is water or a water-based composition, or alcohol, or an alcohol containing composition.  
   
   
       7 . A method of removing surface impurities from a surface comprising the steps of: 
 a) providing a material having at least one impurity particle on a surface thereof,    b) applying a liquid to the surface of the material in the vicinity of the at least one impurity particle;    c) explosively evaporating the liquid, the impurity surface particle being removed as part of the evaporation of the water.    
   
   
       8 . The method of  claim 7 , wherein laser heat is used for the explosive evaporation.  
   
   
       9 . The method of  claim 7 , wherein the liquid is applied by condensation from a gas.  
   
   
       10 . The method of  claim 7 , wherein suction is applied during the explosive evaporation step to assist in impurity particle removal.  
   
   
       11 . The method of  claim 7 , further comprising monitoring the explosive evaporation step for particle removal.  
   
   
       12 . The method of  claim 7 , wherein the liquid is water or a water-based composition, or alcohol, or an alcohol containing composition.  
   
   
       13 . An apparatus for removing surface impurities from a surface of a material comprising: 
 a) means for identifying the location of at least one impurity particle on a surface of the material,    b) means for applying a liquid to the surface in the vicinity of the at least one impurity particle;    c) means for explosively evaporating the liquid, the impurity surface particle being removed as part of the evaporation of the liquid.    
   
   
       14 . The apparatus of  claim 13 , wherein the applying means further comprises means for applying a gas in the vicinity of the at least one impurity particle, wherein the gas and particle are at temperatures such that the liquid condenses from the gas in the vicinity of the at least one impurity particle.  
   
   
       15 . The apparatus of  claim 13 , wherein the means for explosively evaporating the liquid is a laser apparatus.  
   
   
       16 . The apparatus of  claim 13 , further comprising means for applying a suction to the vicinity of the at least one impurity particle to assist in particle removal upon evaporation.  
   
   
       17 . The apparatus of  claim 13 , further comprising means for monitoring the explosive evaporation for particle removal.  
   
   
       18 . The apparatus of  claim 13 , wherein the liquid applying means includes a source of water or a water-containing composition, or alcohol, or an alcohol-containing composition.  
   
   
       19 . The apparatus of  claim 13 , wherein the material is a silicon wafer, and means for handling the silicon wafer are provided to interface with the liquid applying means.  
   
   
       20 . The method of  claim 11 , wherein steps (b) and (c) are repeated one or more times if the monitoring step indicates that the particle has not been removed.