Delivery of dissolved ozone

Abstract

An apparatus and method for delivering ozone to a workpiece. In one embodiment, fluid is sprayed onto a workpiece placed in an ozone-rich environment. Alternatively, ozone is mixed with the fluid prior to spraying the fluid onto the workpiece. When spraying the fluid, the invention pulses the fluid at desired rates to create a substantially uniform layer of ozone-rich fluid on the workpiece. In another embodiment, the workpiece is also slowly rotated during at least a portion of the time the layer of ozone-rich fluid is applied to the workpiece.

What is claimed is:  
     
         1 . An apparatus comprising: 
 at least one wafer processing chamber wherein an ozone rich environment exists within the wafer-processing chamber;    a rotator that creates a gap between a wafer and a wafer cassette, wherein the rotator rotates the wafer while allowing the cassette to remain substantially stationary;    a sprayer; and    a pulsating fluid source, the pulsating fluid source configured to periodically pulse a solution through the sprayer into the ozone rich environment.    
     
     
         2 . The apparatus of  claim 1 , wherein the pulsating fluid source is configured to periodically pulse the solution at approximately two pulses per minute.  
     
     
         3 . The apparatus of  claim 1 , wherein the pulsating fluid source is configured to periodically pulse the solution at approximately one pulse every two seconds.  
     
     
         4 . The apparatus of  claim 1 , wherein the pulsating fluid source is configured to periodically pulse at a range from approximately one pulse every two seconds to approximately five pulses every minute.  
     
     
         5 . The apparatus of  claim 1 , wherein the pulsating fluid source has an 8% duty cycle.  
     
     
         6 . The apparatus of  claim 1 , wherein the pulsating fluid source has a 50% duty cycle.  
     
     
         7 . The apparatus of  claim 1 , wherein the pulsating fluid source has a duty cycle that varies from 3% to 97%.  
     
     
         8 . The apparatus of  claim 1 , wherein the wafer cassette is configured to hold a plurality of wafers.  
     
     
         9 . The apparatus of  claim 1 , wherein the solution is ozone rich.  
     
     
         10 . The apparatus of  claim 1 , wherein the solution combines with the ozone in the ozone rich environment.  
     
     
         11 . The apparatus of  claim 1 , wherein a temperature of the solution is less than approximately 20° C.  
     
     
         12 . The apparatus of  claim 1 , wherein a temperature of the solution is greater than approximately 95° C.  
     
     
         13 . The apparatus of  claim 1 , wherein the sprayer comprises a plurality of spray nozzles.  
     
     
         14 . The apparatus of  claim 1 , wherein the sprayer comprises a nozzle that directs the periodically pulsating fluid into the wafer-processing chamber.  
     
     
         15 . The apparatus of  claim 1 , wherein the rotator rotates the wafer at a speed not exceeding approximately 100 revolutions per minute (RPM).  
     
     
         16 . The apparatus of  claim 15 , wherein the rotator rotates the wafer at approximately 3 revolutions per minute (RPM).  
     
     
         17 . An apparatus comprising: 
 at least one semiconductor-processing chamber;    a rotator that creates a gap between a wafer and a wafer cassette, wherein the rotator rotates the wafer; and    a pulsating fluid source, the pulsating fluid source configured to periodically pulse an ozone-rich solution into the semiconductor-processing chamber.    
     
     
         18 . The apparatus of  claim 17 , wherein the pulsating fluid source is configured to periodically pulse at approximately two pulses per minute.  
     
     
         19 . The apparatus of  claim 17 , wherein the pulsating fluid source is configured to periodically pulse at approximately one pulse every two seconds.  
     
     
         20 . The apparatus of  claim 17 , wherein the pulsating fluid source is configured to periodically pulse the solution at a range from approximately one pulse every two seconds to approximately five pulses every minute.  
     
     
         21 . The apparatus of  claim 17 , wherein the pulsating fluid source has an 8% duty cycle.  
     
     
         22 . The apparatus of  claim 17 , wherein the pulsating fluid source has a 50% duty cycle.  
     
     
         23 . The apparatus of  claim 17 , wherein the pulsating fluid source has a duty cycle that varies from 3% to 97%.  
     
     
         24 . The apparatus of  claim 17 , wherein the wafer cassette is configured to hold a plurality of wafers.  
     
     
         25 . The apparatus of  claim 17 , wherein a temperature of the ozone-rich solution is less than approximately 20° C.  
     
     
         26 . The apparatus of  claim 17 , wherein a temperature of the ozone-rich solution is greater than approximately 95° C.  
     
     
         27 . The apparatus of  claim 17 , wherein the wafer cassette is configured to rotate.  
     
     
         28 . The apparatus of  claim 17 , wherein the rotator rotates the wafer at a speed not exceeding approximately 100 revolutions per minute (RPM).  
     
     
         29 . The apparatus of  claim 28 , wherein the rotator rotates the wafer at approximately 3 revolutions per minute (RPM).  
     
     
         30 . An apparatus for removing a portion of a semiconductor workpiece, the apparatus comprising: 
 a fluid source configured to periodically vary a fluid from a greater flow to a lesser flow, wherein a duty cycle of the periodically varying fluid comprises an amount of time the fluid flows at the greater flow versus an amount of time the fluid flows at the lesser flow plus the amount of time the fluid flows at the greater flow;    one or more nozzles capable of spraying the varying fluid over a semiconductor workpiece; and    at least one rotator configured to at least partially separate the semiconductor workpiece from a carrier, the rotator further configured to rotate the semiconductor workpiece at one or more speeds to, in conjunction with one or more duty cycles of the varying fluid, control a thickness of a boundary layer of the varying fluid on the workpiece,    wherein varying the thickness of the boundary layer varies an amount of ozone that is transferred to the workpiece and wherein the ozone and the varying fluid enhance the removal of a portion of the workpiece.    
     
     
         31 . The apparatus of  claim 30 , wherein the periodically varying fluid varies from the lesser flow to the greater flow at approximately two times per minute.  
     
     
         32 . The apparatus of  claim 30 , wherein the periodically varying fluid varies from the lesser flow to the greater flow at approximately one time every two seconds.  
     
     
         33 . The apparatus of  claim 30 , wherein the periodically varying fluid varies from the lesser flow to the greater flow at a range from approximately one time every two seconds to approximately five times every minute.  
     
     
         34 . The apparatus of  claim 30 , wherein the one or more duty cycles include an 8% duty cycle.  
     
     
         35 . The apparatus of  claim 30 , wherein the one or more duty cycles include a 50% duty cycle.  
     
     
         36 . The apparatus of  claim 30 , wherein the one or more duty cycles include a duty cycle that varies from 3% to 97%.  
     
     
         37 . The apparatus of  claim 30 , wherein the carrier is configured to hold a plurality of semiconductor workpieces.  
     
     
         38 . The apparatus of  claim 30 , wherein the fluid is ozone rich.  
     
     
         39 . The apparatus of  claim 30 , wherein a temperature of the periodically varying fluid is less than approximately 20° C.  
     
     
         40 . The apparatus of  claim 30 , wherein a temperature of the periodically varying fluid is greater than approximately 95° C.  
     
     
         41 . The apparatus of  claim 30 , wherein a temperature of the periodically varying fluid ranges from approximately 20° C. to approximately 95° C.  
     
     
         42 . The apparatus of  claim 30 , wherein a temperature of the periodically varying fluid ranges from approximately 60° C. to approximately 95° C.  
     
     
         43 . The apparatus of  claim 30 , wherein the one or more speeds include a range of speeds not exceeding approximately 100 revolutions per minute (RPM).  
     
     
         44 . The apparatus of  claim 30 , wherein the one or more speeds are below approximately 100 RPM.  
     
     
         45 . The apparatus of  claim 30 , wherein the one or more speeds include 3 revolutions per minute (RPM).  
     
     
         46 . The apparatus of  claim 30 , wherein the workpiece is a semiconductor wafer.  
     
     
         47 . The apparatus of  claim 30 , wherein the lesser flow comprises substantially no flow, thereby creating a pulse of fluid during the greater flow.  
     
     
         48 . An apparatus comprising: 
 a semiconductor-processing chamber;    a means for rotating a wafer, wherein said means creates a gap between the wafer and a wafer cassette; and    a means for periodically pulsating an ozone-rich solution into the semiconductor-processing chamber.    
     
     
         49 . The apparatus of  claim 48 , wherein the means for pulsating is configured to periodically pulse at approximately two pulses per minute.  
     
     
         50 . The apparatus of  claim 48 , wherein the means for pulsating is configured to periodically pulse at approximately one pulse every two seconds.  
     
     
         51 . The apparatus of  claim 48 , wherein the means for pulsating is configured to pulse the ozone-rich solution at a range from approximately one pulse every two seconds to approximately five pulses every minute.  
     
     
         52 . The apparatus of  claim 48 , wherein the means for pulsating has an 8% duty cycle.  
     
     
         53 . The apparatus of  claim 48 , wherein the means for pulsating has a 50% duty cycle.  
     
     
         54 . The apparatus of  claim 48 , wherein the means for pulsating has a duty cycle that varies from 3% to 97%.  
     
     
         55 . The apparatus of  claim 48 , wherein the wafer cassette is configured to hold a plurality of wafers.  
     
     
         56 . The apparatus of  claim 48 , wherein a temperature of the ozone-rich solution is less than approximately 20° C.  
     
     
         57 . The apparatus of  claim 48 , wherein a temperature of the ozone-rich solution is greater than approximately 95° C.  
     
     
         58 . The apparatus of  claim 48 , wherein the wafer cassette is configured to rotate.  
     
     
         59 . The apparatus of  claim 48 , wherein the means for rotating rotates the wafer at a speed not exceeding approximately 100 revolutions per minute (RPM).  
     
     
         60 . The apparatus of  claim 48 , wherein the means for rotating rotates the wafer at approximately 3 revolutions per minute (RPM).