Substrate processing apparatus and substrate processing method

Abstract

A substrate processing apparatus flows a propagation liquid for propagating ultrasonic vibrations, and controls the flow rate thereof. The ultrasonic vibrations are scattered by the flow of the propagation liquid, so that a concentrated impact of the ultrasonic vibrations given on a substrate is relieved. The substrate processing apparatus can increase the output power of ultrasonic vibrations by controlling the flow rate of the propagation liquid while preventing a fine pattern formed on the substrate from stripping or falling down.

1 . A substrate processing apparatus for immersing a substrate in a processing liquid to process said substrate, said substrate processing apparatus comprising: 
 a processing bath retaining said processing liquid;    a holder holding said substrate in said processing bath;    an ultrasonic vibration generator generating ultrasonic vibrations;    a propagation bath retaining a propagation liquid for propagating said ultrasonic vibrations generated by said ultrasonic vibration generator to said processing bath;    a liquid flow generator generating a flow of said propagation liquid in said propagation bath; and    a flow rate controller controlling a flow rate of said propagation liquid generated by said liquid flow generator.    
   
   
       2 . The substrate processing apparatus according to  claim 1 , wherein 
 the flow of said propagation liquid is generated in a direction that crosses travel of said ultrasonic vibrations in said propagation bath.    
   
   
       3 . The substrate processing apparatus according to  claim 2 , wherein 
 said ultrasonic vibration generator is capable of controlling an output power of said ultrasonic vibrations,    said substrate processing apparatus further comprising    a controller controlling said ultrasonic vibration generator and said flow rate controller in synchronization with each other.    
   
   
       4 . The substrate processing apparatus according to  claim 3 , wherein 
 said liquid flow generator includes a supplier supplying said propagation liquid into said propagation bath and a discharger discharging said propagation liquid from said propagation bath.    
   
   
       5 . The substrate processing apparatus according to  claim 4 , further comprising 
 a flow meter measuring the amount of supply of said propagation liquid by said supplier, wherein    said flow rate controller controls the flow rate of said propagation liquid on the basis of measurement by said flow meter.    
   
   
       6 . The substrate processing apparatus according to  claim 5 , wherein 
 said processing bath has its bottom immersed in said propagation liquid retained in said propagation bath, and    said ultrasonic vibration generator generates said ultrasonic vibrations from the bottom of said propagation bath toward the bottom of said processing bath.    
   
   
       7 . The substrate processing apparatus according to  claim 6 , wherein 
 said supplier and said discharger are provided in opposite sides to each other with said processing bath interposed therebetween.    
   
   
       8 . The substrate processing apparatus according to  claim 7 , wherein 
 said controller controls said ultrasonic vibration generator and said flow rate controller in synchronization with each other on the basis of a predetermined correlation.    
   
   
       9 . The substrate processing apparatus according to  claim 8 , wherein 
 said propagation liquid is deionized water.    
   
   
       10 . A substrate processing method of processing a substrate, comprising the steps of: 
 (a) immersing a substrate in a processing liquid retained in a processing bath;    (b) generating ultrasonic vibrations;    (c) propagating said ultrasonic vibrations to said processing bath through a propagation liquid;    (d) generating a flow of said propagation liquid; and    (e) controlling a flow rate of said propagation liquid.    
   
   
       11 . The substrate processing method according to  claim 10 , wherein 
 in said step (d), the flow of said propagation liquid is generated in a direction that crosses travel of said ultrasonic vibrations.    
   
   
       12 . The substrate processing method according to  claim 11 , further comprising the step of (f) controlling an output power of said ultrasonic vibrations.  
   
   
       13 . The substrate processing method according to  claim 12 , wherein 
 in said step (e), the flow rate of said propagation liquid is controlled on the basis of the output power of ultrasonic vibrations controlled in said step (f).    
   
   
       14 . The substrate processing method according to  claim 13 , wherein said propagation liquid is retained in a propagation bath, and 
 in said step (d), the flow of said propagation liquid is generated by supply of said propagation liquid into said propagation bath and discharge of said propagation liquid from said propagation bath.