High-Power Pulsed Magnetron Sputtering

Abstract

Magnetically enhanced sputtering methods and apparatus are described. A magnetically enhanced sputtering source according to the present invention includes an anode and a cathode assembly having a target that is positioned adjacent to the anode. An ionization source generates a weakly-ionized plasma proximate to the anode and the cathode assembly. A magnet is positioned to generate a magnetic field proximate to the weakly-ionized plasma. The magnetic field substantially traps electrons in the weakly-ionized plasma proximate to the sputtering target. A power supply produces an electric field in a gap between the anode and the cathode assembly. The electric field generates excited atoms in the weakly ionized plasma and generates secondary electrons from the sputtering target. The secondary electrons ionize the excited atoms, thereby creating a strongly-ionized plasma having ions that impact a surface of the sputtering target to generate sputtering flux.

1 - 40 . (canceled)  
   
   
       41 . A magnetically enhanced sputtering source comprising: 
 a) an anode;    b) a cathode assembly that is positioned adjacent to the anode, the cathode assembly including a sputtering target;    c) an ionization source that generates a weakly-ionized plasma proximate to the anode and the cathode assembly;    d) a magnet that is positioned to generate a magnetic field proximate to the weakly-ionized plasma, the magnetic field substantially trapping electrons in the weakly-ionized plasma proximate to the sputtering target; and    e) a power supply generating a voltage pulse that produces an electric field between the cathode assembly and the anode, the voltage pulse having at least one of an amplitude and a rise time that increases an excitation rate of ground state atoms that are present in the weakly-ionized plasma to create a multi-step ionization process that generates a strongly-ionized plasma without forming an arc discharge.    
   
   
       42 . The sputtering source of  claim 41  wherein the power supply generates a constant power.  
   
   
       43 . The sputtering source of  claim 41  wherein the power supply generates a constant voltage.  
   
   
       44 . The sputtering source of  claim 41  wherein the electric field comprises a quasi-static electric field.  
   
   
       45 . The sputtering source of  claim 41  wherein the electric field comprises a pulsed electric field.  
   
   
       46 . The sputtering source of  claim 41  wherein the at least one of the amplitude and the rise time of the voltage pulse is chosen to causes substantially uniform erosion of the sputtering target.  
   
   
       47 . The sputtering source of  claim 41  further comprising a substrate support that is positioned in a path of the sputtering flux.  
   
   
       48 . The sputtering source of  claim 47  further comprising a temperature controller that controls the temperature of the substrate support.  
   
   
       49 . The sputtering source of  claim 47  further comprising a bias voltage power supply that applies a bias voltage to a substrate that is positioned on the substrate support.  
   
   
       50 . The sputtering source of  claim 41  wherein the ionization source is chosen from the group comprising a UV source, an X-ray source, an electron beam source, and an ion beam source.  
   
   
       51 . The sputtering source of  claim 41  wherein the sputtering target is formed of a material chosen from the group comprising a metallic material, a polymer material, a superconductive material, a magnetic material, a non-magnetic material, a conductive material, a non-conductive material, a composite material, a reactive material, and a refractory material.  
   
   
       52 . A method of generating sputtering flux, the method comprising: 
 a) ionizing a feed gas to generate a weakly-ionized plasma proximate to a sputtering target;    b) generating a magnetic field proximate to the weakly-ionized plasma, the magnetic field substantially trapping electrons in the weakly-ionized plasma proximate to the sputtering target;    c) generating a voltage pulse having at least one of an amplitude and a rise time that increases an excitation rate of ground state atoms present in the weakly-ionized plasma to create a multi-step ionization process; and    d) applying the voltage pulse to the weakly-ionized plasma to generate a strongly-ionized plasma without forming an arc discharge.    
   
   
       53 . The method of  claim 52  wherein the voltage pulse generates a quasi-static electric field.  
   
   
       54 . The method of  claim 52  further comprising selecting at least one of the amplitude and the rise time of the voltage pulse to increase an ionization rate of the strongly-ionized plasma.  
   
   
       55 . The method of  claim 52  further comprising selecting at least one of the amplitude and a pulse width of the voltage pulse to increase an ionization rate of the strongly-ionized plasma.  
   
   
       56 . The method of  claim 52  further comprising selecting at least one of the amplitude and a pulse width of the voltage pulse to cause the strongly-ionized plasma to be substantially uniform in an area adjacent to a surface of the sputtering target.  
   
   
       57 . The method of  claim 52  further comprising controlling a temperature of the film.  
   
   
       58 . The method of  claim 52  further comprising applying a bias voltage to the film.  
   
   
       59 . The method of  claim 52  wherein the ionizing the feed gas comprises exposing the feed gas to at least one of a UV source, an X-ray source, an electron beam source, and an ion beam source.  
   
   
       60 . A magnetically enhanced sputtering source comprising: 
 a) means for ionizing a feed gas to generate a weakly-ionized plasma proximate to a sputtering target;    b) means for generating a magnetic field proximate to the weakly-ionized plasma, the magnetic field substantially trapping electrons in the weakly-ionized plasma proximate to the sputtering target; and    c) means for generating a voltage pulse with at least one of an amplitude and a rise time chosen for generating a multi-step ionization process; and    d) applying the voltage pulse to the weakly-ionized plasma to generate a strongly ionized plasma.