Method and apparatus for controlled transient cavitation

Abstract

The invention relates to a method for creating transient cavitation comprising the steps of creating gas bubbles having a range of bubble sizes in a liquid, creating an acoustic field and subjecting the liquid to the acoustic field, characterized in that the range of bubble sizes and/or the characteristics of the acoustic field are selected to tune them to each other, thereby controlling transient cavitation in the selected range of bubble sizes. It also relates to an apparatus suitable for performing the method according to the invention.

1 . A method for creating transient cavitation comprising the steps of: 
 creating gas bubbles having a range of bubble sizes in a liquid;    creating an acoustic field; and    subjecting the liquid to the acoustic field,    characterized in that the range of bubble sizes and/or the characteristics of the acoustic field are selected to tune them to each other, thereby controlling transient cavitation in the selected range of bubble sizes.    
   
   
       2 . A method according to  claim 1  characterized in that the range of bubble sizes is selected subsequent to and depending on the selection of the characteristics of the acoustic field.  
   
   
       3 . A method according to  claim 1  characterized in that the characteristics of the acoustic field are selected subsequent to and depending on the selected range of bubble sizes.  
   
   
       4 . A method according to  claim 1  characterized in that the step of creating gas bubbles having a selected range of bubble sizes comprises dissolving gas in the liquid by means of a gasification unit or any means to dissolve gas in the liquid.  
   
   
       5 . A method according to  claim 1  characterized in that the step of creating gas bubbles having a selected range of bubble sizes comprises injection of gas in the liquid by means of a bubbler system, a capillary, a nozzle, a membrane contactor or any means to inject gas bubbles into the liquid.  
   
   
       6 . A method according to  claim 1  characterized in that the step of creating gas bubbles having a selected range of bubble sizes comprises a pressure drop or comprises one or multiple compression/decompression cycles.  
   
   
       7 . A method according to  claim 1  characterized in that the step of creating gas bubbles having a selected range of bubble sizes comprises a raise in temperature or comprises one or multiple cycles of heating/cooling the liquid.  
   
   
       8 . A method according to  claim 1  characterized in that the step of creating gas bubbles having a selected range of bubble sizes comprises a step of subjecting the liquid to a an additional acoustic field.  
   
   
       9 . A method according to  claim 1  characterized in that the step of creating gas bubbles having a selected range of bubble sizes comprises dissolving or injecting two or more different gasses into the liquid.  
   
   
       10 . A method according to  claim 1  characterized in that the step of creating gas bubbles having a selected range of bubble sizes comprises adding a surfactant to the liquid.  
   
   
       11 . A method according to  claim 1  characterized in that the range of bubble sizes is varied over time.  
   
   
       12 . A method according to  claim 1  characterized in that the acoustic field comprises one or more frequencies.  
   
   
       13 . A method according to  claim 1 , further comprising the step of measuring the range of bubble sizes.  
   
   
       14 . A method according to  claim 13 , further comprising the step of controlling the characteristics of the acoustic field subsequently to and dependent on the measurement.  
   
   
       15 . A method according to  claim 13 , further comprising the step of controlling the range of bubble sizes subsequently and dependent on the measurement.  
   
   
       16 . A method according to  claim 1 , characterized in that it is used for cleaning semiconductor substrates.  
   
   
       17 . An apparatus comprising: 
 means for creating gas bubbles having a range of bubble sizes in a liquid,    means for creating an acoustic field and    means for subjecting the liquid to the acoustic field,    characterized in that the means for creating the gas bubbles having a range of bubble sizes and/or the means for creating the acoustic field are designed to tune the range of bubble sizes and the characteristics of the acoustic field to each other, thereby controlling transient cavitation in the selected range of bubble sizes.    
   
   
       18 . An apparatus according to  claim 17  characterized in that the means for creating gas bubbles having a range of bubble sizes comprise a gasification unit or any means to dissolve gas in the liquid.  
   
   
       19 . An apparatus according to  claim 17  characterized in that the means for creating gas bubbles having a range of bubble sizes comprise a valve, a nozzle, a membrane contactor or any means to inject gas bubbles into the liquid.  
   
   
       20 . An apparatus according to  claim 17  characterized in that the means for creating gas bubbles having a range of bubble sizes comprise a heat exchanging system or any means for heating/cooling the liquid.