Multifrequency plasma reactor and method of etching

Abstract

A multifrequency plasma reactor includes first, second and third power generators are operably coupled to at least one of an upper and lower electrode for generating power signals. The plasma reactor further includes a controller for selectively activating the power generators according to an activation profile that results in the formation of a desirable narrow gap via in a semiconductor wafer. A method of generating a plasma in the reactor for etching the semiconductor wafer is also described by way of configuring the power generators according to various activation configurations during various phases of the etching process.

1 . A method of generating a plasma in a plasma reactor, including a vacuum chamber containing a gas and first, second and third electrodes therein operably coupled to respective first, second and third power generators, the method comprising: 
 configuring the first, second and third power generators to a first activation configuration during a first phase of an etch process; and    reconfiguring the first, second and third power generators to at least a second activation configuration during at least a second phase of the etch process.    
   
   
       2 . The method of  claim 1  wherein configuring comprises activating the first and third power generators and deactivating the second power generator during the first phase of the etch process.  
   
   
       3 . The method of  claim 2  wherein reconfiguring comprises activating the second and third power generators and deactivating the first power generator during at least the second phase of the etch process.  
   
   
       4 . The method of  claim 1  further comprising reconfiguring the first, second and third power generators to a third activation configuration during a third phase of the etch process.  
   
   
       5 . A method of etching a semiconductor wafer in a plasma reactor, comprising: 
 generating first, second and third power signals at upper and lower electrodes respectively coupled to first, second and third power generators; and    individually activating the first, second and third power generators to control the etching of the semiconductor wafer.    
   
   
       6 . The method of  claim 5  wherein individually activating comprises activating the second and third power generators and deactivating the first power generator.  
   
   
       7 . The method of  claim 5  wherein individually activating comprises activating the first and third power generators and deactivating the second power generator.  
   
   
       8 . The method of  claim 5  wherein individually activating comprises activating the first and second power generators and deactivating the third power generator.  
   
   
       9 . The method of  claim 5  wherein individually activating comprises activating the first, second and third power generators.  
   
   
       10 . The method of  claim 5  wherein individually activating comprises: 
 configuring the first, second and third power generators to a first activation configuration during a first phase of the etching of the semiconductor wafer; and    reconfiguring the first, second and third power generators to at least a second activation configuration during at least a second phase of the etching of the semiconductor wafer.    
   
   
       11 . The method of  claim 5  wherein individually activating comprises configuring the first, second and third power generators to a plurality of activation configurations during a corresponding plurality of phases of a duty cycle of the etching of the semiconductor wafer.  
   
   
       12 . The method of  claim 5  further comprising independently varying power levels of the first, second and third power generators during the etching of the semiconductor wafer.  
   
   
       13 . The method of  claim 12  wherein independently varying further includes varying the power level of each of the first, second, and third power generators to produce a desired via profile.  
   
   
       14 . A method for etching a semiconductor wafer, comprising: 
 providing a plasma reactor, including: 
 first, second and third power generators coupled to upper and lower electrodes; and  
 a controller for selectively activating the first, second and third power generators; and  
   controlling the first, second and third power generators with the controller to control the etching of the semiconductor wafer.    
   
   
       15 . The method of  claim 14  wherein controlling comprises individually activating in a first configuration at least one of the first, second and third power generators during at least one phase of the etching of the semiconductor wafer.  
   
   
       16 . The method of  claim 15  further comprising individually activating in a second configuration at least one of the first, second and third power generators during at least another phase of the etching of the semiconductor wafer.