Method of coating high aspect ratio features

Abstract

A sputtering apparatus includes a chamber for containing a feed gas. An anode is positioned inside the chamber. A cathode assembly comprising target material is positioned adjacent to an anode inside the chamber. A magnet is positioned adjacent to cathode assembly. A platen that supports a substrate is positioned adjacent to the cathode assembly. An output of the power supply is electrically connected to the cathode assembly. The power supply generates a plurality of voltage pulse trains comprising at least a first and a second voltage pulse train. The first voltage pulse train generates a first discharge from the feed gas that causes sputtering of a first layer of target material having properties that are determined by at least one of a peak amplitude, a rise time, and a duration of pulses in the first voltage pulse train. The second voltage pulse train generates a second discharge from the feed gas that causes sputtering of a second layer of target material having properties that are determined by at least one of a peak amplitude, a rise time, and a duration of pulses in the second voltage pulse train.

1 - 35 . (canceled) 
     
     
         36 . A method of forming a thin film on a substrate comprising at least one of trenches and vias, the method comprising:
 a) supplying a feed gas proximate to an anode and a cathode assembly comprising target material;   b) applying a DC electrical current to an electromagnet coil, the electromagnet coil generating a magnetic field proximate to the cathode assembly that focuses an existing plasma;   c) generating voltage pulses with a pulsed power supply;   d) applying the voltage pulses generated by the pulsed power supply between the anode and the cathode assembly to generate a high density plasma from the weakly ionized plasma proximate to the target material, a rise time of the voltage pulses, a duration of the voltage pulses, an amplitude of the voltage pulses, and the feed gas pressure being chosen to control a density of excited feed gas atoms corresponding to a rate of collisions between excited feed gas atoms and sputtered target material atoms, so as to result in a desired rate of ionization of sputtered material atoms proximate to the substrate; and   e) applying a RF bias voltage to the substrate to control an energy of ions from sputtered material atoms impacting the substrate comprising at least one of trenches and vias, thereby forming a thin film from sputtered target atoms and ions.   
     
     
         37 . The method as defined in  claim 36 , including positioning a ring-shaped pre-ionizing electrode proximate to a magnetron assembly that is connected with a RF power supply, the pre-ionizing electrode generating weakly ionized plasma. 
     
     
         38 . A sputtering apparatus comprising: a) a chamber for containing a feed gas; b) an anode that is positioned inside the chamber; c) a cathode assembly comprising target material that is positioned adjacent to the anode inside the chamber; d) a magnet positioned adjacent to cathode assembly; e) a platen that supports a substrate positioned adjacent to the cathode assembly; f) a power supply having an output that is electrically connected to the cathode assembly, the power supply generating a plurality of voltage pulse trains comprising at least a first and a second voltage pulse train, the first voltage pulse train generating a first discharge from the feed gas that causes sputtering of a first layer of target material having properties that are determined by at least one of a peak amplitude, a rise time, and a duration of pulses in the first voltage pulse train, the second voltage pulse train generating a second discharge from the feed gas that causes sputtering of a second layer of target material having properties that are determined by at least one of a peak amplitude, a rise time, and a duration of pulses in the second voltage pulse train. 
     
     
         39 . The plasma source of  claim 38  wherein the cathode assembly comprises a segmented cathode assembly comprising at least a first and a second isolated cathode segment. 
     
     
         40 . The plasma source of  claim 39  wherein the power supply applies the first voltage pulse train to the first isolated cathode segment and applies the second voltage pulse train to the second isolated segment. 
     
     
         41 . The plasma source of  claim 38  wherein the cathode assembly comprises a first and a second separate cathode assembly. 
     
     
         42 . The plasma source of  claim 41  wherein the power supply applies the first voltage pulse train to the first separate cathode assembly and applies the second voltage pulse train to the second separate cathode assembly.