Slurry supply apparatus and method

Abstract

A slurry supply apparatus includes a slurry supply tank, CMP unit, ultrasonic dispersion unit, and filter. In the slurry supply tank, a slurry obtained by dispersing abrasive grains with a predetermined grain size in a chemical solution is agitated and stored. The slurry is supplied from the slurry supply tank to the CMP unit through a slurry supply line. The ultrasonic dispersion unit pulverizes the abrasive grains formed by cohesion and supplied from the slurry supply tank through the slurry supply tank. The filter removes an abrasive grain with the predetermined grain size or less, which is supplied from the ultrasonic dispersion unit and supplies the resultant slurry to the CMP unit. A slurry supply method is also disclosed.

What is claimed is:  
     
         1 . A slurry supply apparatus comprising: 
 a slurry supply tank in which a slurry obtained by dispersing abrasive grains with a predetermined grain size in a chemical solution is agitated and stored;    a polishing unit to which the slurry is supplied from said slurry supply tank through a slurry supply line;    ultrasonic dispersion means for pulverizing the abrasive grains formed by cohesion and supplied from said slurry supply tank through said slurry supply tank; and    filter means for removing an abrasive grain with not less than the predetermined grain size, which is supplied from said ultrasonic dispersion means and supplying the resultant slurry to said polishing unit.    
     
     
         2 . An apparatus according to  claim 1 , wherein said ultrasonic dispersion means is clamped on a pipe of the slurry supply line, and adapted to apply ultrasonic vibration to the slurry through the pipe.  
     
     
         3 . An apparatus according to  claim 1 , wherein said polishing unit is a chemical mechanical polishing (CMP) unit.  
     
     
         4 . An apparatus according to  claim 1 , wherein said filter means is formed by connecting in a subordinate manner a plurality of filters that remove the abrasive grains from those with a large grain size to those with a small grain size gradually.  
     
     
         5 . An apparatus according to  claim 1 , wherein said ultrasonic dispersion means has an ultrasonic oscillator which generates ultrasonic waves in a range of 0.1 W/cm 2  to several 100 W/cm 2  at a frequency of 10 kHz to several GHz.  
     
     
         6 . A slurry supply method of supplying a slurry, obtained by dispersing abrasive grains with a predetermined grain size in a chemical solution and agitated and stored in a slurry supply tank, to a polishing unit through a slurry supply line, comprising the steps of: 
 pulverizing the abrasive grains formed by cohesion and supplied from the slurry supply tank by using ultrasonic vibration; and    removing an abrasive grain with not less than the predetermined grain size from the pulverized abrasive grains by using a filter, and thereafter supplying the slurry containing abrasive grains with less than the predetermined grain size to the polishing unit.    
     
     
         7 . A method according to  claim 6 , wherein the step of pulverizing comprises the steps of 
 clamping an ultrasonic dispersion unit for applying ultrasonic vibration on a pipe of the slurry supply line, and    applying ultrasonic vibration from the ultrasonic dispersion unit to the slurry through the pipe.    
     
     
         8 . A method according to  claim 6 , wherein the polishing unit is a chemical mechanical polishing (CMP) unit.  
     
     
         9 . A method according to  claim 6 , wherein the step of pulverizing has the step of generating ultrasonic vibration of ultrasonic waves in a range of 0.1 W/cm 2  to several 100 W/cm 2  at a frequency of 10 kHz to several GHz.