High peak power plasma pulsed supply with arc handling

Abstract

A magnetron sputtering system is provided comprising a pulsed DC power supply capable of delivering peak powers of 0.1 megawatts to several megawatts with a peak power density greater than 1 kW/cm 2 . A sputtering plasma in a highly ionized state is created without first adopting an arc discharge state. The power supply has a pulsing circuit comprising an energy storage capacitor and serially connected inductor with a switching means for disconnecting the pulsing circuit from the plasma and recycling the inductor energy back to the energy storage capacitor at the detection of an arc condition. The energy storage capacitor and the serially connected inductor provide an impedance match to the plasma, limits the current rate of rise and peak magnitude in the event of an arc, and shapes the voltage pulses to the plasma.

I claim:  
     
         1 . A method of sputter deposition, comprising: 
 a) providing a plasma chamber with a sputtering gas disposed therein;    b) providing a material target disposed in the plasma chamber;    c) providing a pulsed DC power supply that periodically applies a voltage pulse to the material target, the voltage pulse ionizing the sputtering gas to create a plasma, the plasma adopting a highly ionized state without first adopting an arc discharge state; and    d) sputtering atoms from the target by bombarding the material target with ions from the plasma, the atoms being then deposited on the surface of a substrate in proximity to the plasma.    
     
     
         2 . The method of  claim 1 , wherein the pulsed DC power supply delivers power greater than 0.1 MW with a peak power density greater than 1 kW/cm 2 .  
     
     
         3 . The method of  claim 1 , wherein the plasma adopts the highly ionized state without first adopting an arc discharge state by controlling the voltage rate of rise of the voltage pulse applied to the material target.  
     
     
         4 . The method of  claim 3 , wherein the voltage rate of rise of the voltage pulse is controlled using a circuit comprising a resistor in series with a capacitor.  
     
     
         5 . The method of  claim 1 , wherein the plasma adopts the highly ionized state without first adopting an arc discharge state by limiting the magnitude of the voltage pulse to a maximum level.  
     
     
         6 . The method of  claim 5 , wherein the magnitude of the voltage pulse is limited using a circuit comprising a resistor in series with a capacitor.  
     
     
         7 . The method of  claim 5 , wherein the magnitude of the voltage pulse is limited using a circuit comprising a reverse biased diode, a capacitor, and a clamp voltage supply.  
     
     
         8 . A sputter deposition system, comprising: 
 a) a plasma chamber with a sputtering gas disposed therein;    b) a material target disposed in the plasma chamber;    c) a pulsed DC power supply that periodically applies a voltage pulse to the material target, the voltage pulse ionizing the sputtering gas to create a highly ionized plasma; and    d) pulse shaping circuitry that shapes the voltage pulse so as to allow the plasma to adopt a highly ionized state without first adopting an arc discharge state.    
     
     
         9 . The sputter deposition system of  claim 8 , wherein the pulse shaping circuitry controls the voltage rate of rise of the voltage pulse.  
     
     
         10 . The sputter deposition system of  claim 9 , wherein the pulse shaping circuitry comprises a resistor in series with a capacitor.  
     
     
         11 . The sputter deposition system of  claim 8 , wherein the pulse shaping circuitry limits the magnitude of the voltage pulse to a maximum level.  
     
     
         12 . The sputter deposition system of  claim 11 , wherein the pulse shaping circuitry comprises a reverse biased diode, a capacitor, and a clamp voltage supply.