Low-frequency bias power in hdp-cvd processes

Abstract

A substrate processing system has a housing that defines a process chamber. A substrate holder disposed within the process chamber supports a substrate during substrate processing. A gas-delivery system introduces a gas into the process chamber. A pressure-control system maintains a selected pressure within the process chamber. A high-density plasma generating system forms a plasma having a density greater than 10 11 ions/cm 3 within the process chamber. A radio-frequency bias system generates an electrical bias on the substrate at a frequency less than 5 MHz. A controller controls the gas-delivery system, the pressure-control system, the high-density plasma generating system, and the radio-frequency bias system.

1 . A method for depositing a silicon oxide film on a substrate disposed in a substrate processing chamber, the method comprising:
 flowing a process gas into the substrate processing chamber, the process gas comprising a silicon source, an oxygen source, and a fluent gas;   forming a plasma having an ion density greater than 10 11  ions/cm 3  from the process gas;   applying an electrical bias to the substrate at a frequency less than 5 MHz; and   depositing the silicon oxide film over the substrate with the plasma in a process that has simultaneous deposition and sputtering components.   
   
   
       2 . The method recited in  claim 1  wherein the frequency is less than 3 MHz. 
   
   
       3 . The method recited in  claim 1  wherein:
 the substrate has a gap formed between adjacent raised surfaces; and   depositing the film over the substrate with the plasma comprises depositing the film within the gap.   
   
   
       4 . The method recited in  claim 1  further comprising maintaining a pressure within the process chamber less than 2 mtorr. 
   
   
       5 . The method recited in  claim 1  further comprising maintaining a pressure within the process chamber less than 1 mtorr. 
   
   
       6 . The method recited in  claim 1  wherein the electrical bias has a power greater than 5000 W. 
   
   
       7 . The method recited in  claim 1  further comprising electronically sweeping the frequency through a frequency range to determine a frequency that minimizes a power reflected from the substrate processing chamber. 
   
   
       8 . The method recited in  claim 7  wherein electronically sweeping the frequency through the frequency range is performed with a period substantially between 50 and 100 ms. 
   
   
       9 . A method for depositing a silicon oxide film on a substrate disposed in a substrate processing chamber, the method comprising:
 flowing a process gas into the substrate processing chamber, the process gas comprising a silicon source, an oxygen source, and a fluent gas;   forming a plasma having an ion density greater than 10 11  ions/cm 3  from the process gas;   applying an electrical bias to the substrate;   electronically sweeping the electrical bias through a frequency range to determine a frequency that minimizes a power reflected from the substrate processing chamber; and   depositing the silicon oxide film over the substrate with the plasma in a process that has simultaneous deposition and sputtering components.   
   
   
       10 . The method recited in  claim 9  wherein the frequency is less than 5 MHz. 
   
   
       11 . The method recited in  claim 9  wherein the frequency range is approximately 2.7-3.3 MHz. 
   
   
       12 . The method recited in  claim 9  wherein:
 the substrate has a gap formed between adjacent raised surfaces; and   depositing the film over the substrate with the plasma comprises depositing the film within the gap.   
   
   
       13 . The method recited in  claim 9  further comprising maintaining a pressure within the process chamber less than 2 mtorr. 
   
   
       14 . The method recited in  claim 9  further comprising maintaining a pressure within the process chamber less than 1 mtorr. 
   
   
       15 . The method recited in  claim 9  wherein the electrical bias has a power greater than 5000 W. 
   
   
       16 . The method recited in  claim 9  wherein electronically sweeping the frequency through the frequency range is performed with a period substantially between 50 and 100 ms.