Hard mask deposition using direct current superimposed radio frequency plasma

Abstract

A plasma processing apparatus includes a plasma processing chamber, a substrate holder disposed in the chamber, and a radio frequency (RF) electrode disposed within the chamber, an RF power source configured to supply continuous wave RF power having frequency in the very high frequency range to the RF electrode, and a direct current (DC) power source configured to supply continuous wave DC power to the chamber through an RF choke. The DC power is supplied concurrently with the RF power. The RF power source is electrically coupled to the RF electrode through an impedance matching circuit and is separate from the DC power source. The RF electrode may be an upper electrode or a lower electrode, such as the substrate holder. The DC power may be supplied to an upper or lower electrode, or through a wall of the chamber.

What is claimed is: 
     
         1 . A plasma processing apparatus comprising:
 a plasma processing chamber;   a radio frequency (RF) electrode disposed within the plasma processing chamber,   an RF power source electrically coupled to the RF electrode through an impedance matching circuit, the RF power source being configured to supply continuous wave RF power to the RF electrode, the continuous wave RF power comprising a frequency in the very high frequency (VHF) range;   a direct current (DC) power source separate from the RF power source, the DC power source being configured to supply continuous wave DC power to the plasma processing chamber through an RF choke, the continuous wave DC power being supplied concurrently with the continuous wave RF power; and   a substrate holder disposed in the plasma processing chamber.   
     
     
         2 . The plasma processing apparatus of  claim 1 , wherein the DC power source is electrically coupled to the RF electrode through the RF choke and further configured to supply the continuous wave DC power to the plasma processing chamber by supplying the continuous wave DC power to the RF electrode. 
     
     
         3 . The plasma processing apparatus of  claim 2 , wherein:
 the RF electrode is an upper electrode disposed over the substrate holder; and   the DC power applies a positive DC voltage to the upper electrode.   
     
     
         4 . The plasma processing apparatus of  claim 2 , wherein:
 the RF electrode is the substrate holder; and   the DC power applies a negative DC voltage to the substrate holder.   
     
     
         5 . The plasma processing apparatus of  claim 1 , wherein:
 the RF electrode is an upper electrode disposed over the substrate holder;   the DC power source is electrically coupled to the substrate holder through the RF choke and further configured to supply the continuous wave DC power to the plasma processing chamber by supplying the continuous wave DC power to the substrate holder; and   the DC power applies a negative DC voltage to the substrate holder.   
     
     
         6 . The plasma processing apparatus of  claim 1 , wherein the DC power source is further configured to supply the continuous wave DC power to the plasma processing chamber through a wall of the plasma processing chamber using a DC power vacuum feedthrough. 
     
     
         7 . The plasma processing apparatus of  claim 1 , further comprising a temperature controller thermally coupled to the substrate holder and configured to cool a substrate supported by the substrate holder during plasma processing. 
     
     
         8 . The plasma processing apparatus of  claim 1 , wherein:
 the RF electrode is an upper electrode disposed over the substrate holder; and   the RF electrode is a direct carbon source.   
     
     
         9 . The plasma processing apparatus of  claim 1 , further comprising:
 an upper electrode disposed over the substrate holder, the upper electrode being a direct carbon source, wherein the RF electrode is the substrate holder.   
     
     
         10 . A plasma processing apparatus comprising:
 a plasma processing chamber;   a substrate holder disposed in the plasma processing chamber, the substrate holder being a lower electrode of the plasma processing chamber;   a radio frequency (RF) electrode disposed above the substrate holder within the plasma processing chamber, the RF electrode being an upper electrode of the plasma processing chamber;   an RF power source electrically coupled to the RF electrode through an impedance matching circuit, the RF power source being configured to supply continuous wave RF power to the RF electrode, the continuous wave RF power comprising a frequency greater than 60 MHz; and   a direct current (DC) power source separate from the RF power source and electrically coupled to the RF electrode through an RF choke, the DC power source being configured to supply continuous wave DC power to the RF electrode, the continuous wave DC power being supplied concurrently with the continuous wave RF power.   
     
     
         11 . The plasma processing apparatus of  claim 10 , wherein the DC power applies a positive voltage to the RF electrode. 
     
     
         12 . The plasma processing apparatus of  claim 11 , wherein the positive voltage is between 0 V and about 200 V. 
     
     
         13 . The plasma processing apparatus of  claim 10 , further comprising a temperature controller thermally coupled to the substrate holder and configured to cool a substrate supported by the substrate holder during plasma processing. 
     
     
         14 . The plasma processing apparatus of  claim 10 , wherein the RF electrode is a direct carbon source. 
     
     
         15 . A plasma processing apparatus comprising:
 a plasma processing chamber;   a substrate holder disposed in the plasma processing chamber, the substrate holder being a lower electrode of the plasma processing chamber;   a radio frequency (RF) electrode disposed above the substrate holder within the plasma processing chamber, the RF electrode being an upper electrode of the plasma processing chamber;   an RF power source electrically coupled to the RF electrode through an impedance matching circuit, the RF power source being configured to supply continuous wave RF power to the RF electrode, the continuous wave RF power comprising a frequency in the very high frequency (VHF) range; and   a direct current (DC) power source separate from the RF power source, the DC power source being configured to supply continuous wave DC power to the plasma processing chamber through an RF choke, the continuous wave DC power being supplied concurrently with the continuous wave RF power.   
     
     
         16 . The plasma processing apparatus of  claim 15 , wherein the DC power source is electrically coupled to the RF electrode through the RF choke and further configured to supply the continuous wave DC power to the plasma processing chamber by supplying the continuous wave DC power to the RF electrode. 
     
     
         17 . The plasma processing apparatus of  claim 15 , wherein:
 the DC power source is electrically coupled to the substrate holder through the RF choke and further configured to supply the continuous wave DC power to the plasma processing chamber by supplying the continuous wave DC power to the substrate holder; and   the DC power applies a negative DC voltage to the substrate holder.   
     
     
         18 . The plasma processing apparatus of  claim 15 , wherein the DC power source is further configured to supply the continuous wave DC power to the plasma processing chamber through a wall of the plasma processing chamber using a DC power vacuum feedthrough. 
     
     
         19 . The plasma processing apparatus of  claim 15 , further comprising a temperature controller thermally coupled to the substrate holder and configured to cool a substrate supported by the substrate holder during plasma processing. 
     
     
         20 . The plasma processing apparatus of  claim 15 , wherein the RF electrode is a direct carbon source.