Alternating asymmetrical plasma generation in a process chamber

Abstract

Embodiments of the invention generally provide etch or CVD plasma processing methods and apparatus used to generate a uniform plasma across the surface of a substrate by modulation pulsing the power delivered to a plurality of plasma controlling devices found in a plasma processing chamber. The plasma generated and/or sustained in the plasma processing chamber is created by the one or more plasma controlling devices that are used to control, generate, enhance, and/or shape the plasma during the plasma processing steps by use of energy delivered from a RF power source. Plasma controlling devices may include, for example, one or more coils (inductively coupled plasma), one or more electrodes (capacitively coupled plasma), and/or any other energy inputting device such as a microwave source.

1 . A method of processing a substrate in a plasma chamber, comprising: 
 amplitude modulating the RF power delivered to a first plasma controlling device at a first modulation pulse frequency and at a first power level;    amplitude modulating the RF power delivered to a second plasma controlling device at a second modulation pulse frequency and at a second power level;    synchronizing the amplitude modulation of the RF power to the first plasma controlling device and the second plasma controlling device; and    controlling the amplitude modulation of the RF power such that the overlap in time and the shape of the amplitude modulated RF power delivered to the first and second plasma controlling devices is controlled to improve the uniformity of the process completed on the substrate.    
   
   
       2 . The method of  claim 1 , wherein the first modulation pulsing frequency and the second modulation pulsing frequency are between about 0.1 Hz and about 100,000 Hz.  
   
   
       3 . The method of  claim 1 , wherein the first RF power level and the second RF power level are between about 0 Watts and about 5000 Watts.  
   
   
       4 . The method of  claim 1 , wherein the ratio of the first RF power level to the second RF power level or the second RF power level to the first RF power level is between about 1:1 and about 100:1.  
   
   
       5 . The method of  claim 1 , wherein the first plasma controlling device is an inductive coil, an electrode, or a torroidal source.  
   
   
       6 . The method of  claim 1 , wherein the second plasma controlling device is an inductive coil, an electrode or a torroidal source.  
   
   
       7 . The method of  claim 1 , wherein the amplitude modulating of the RF power supplied to the second plasma second devices is less than the first plasma controlling device at a first time, and the RF power supplied to the first plasma controlling devices is less than the second plasma controlling device at a second time.  
   
   
       8 . The method of  claim 1 , wherein the shape of the amplitude modulated RF power is rectangular in shape, trapezoidal in shape, triangular in shape or sinusoidal in shape.  
   
   
       9 . The method of  claim 1 , further comprising: 
 amplitude modulating the RF power delivered to a third plasma controlling device at a third modulation pulsing frequency and at a third power level;    synchronizing the amplitude modulating of the RF power to the first, second and third plasma controlling devices; and    controlling the amplitude modulation of the RF power such that the overlap of the amplitude modulated RF power delivered to the first, second and third plasma controlling devices is controlled to improve the uniformity of the process completed on the substrate.    
   
   
       10 . A method of processing a substrate in a plasma chamber, comprising: 
 generating a first torroidal path of plasma that passes near and transverse a surface of the substrate using a first torroidal plasma controlling device;    generating a second torroidal path of plasma that passes near and transverse a surface of the substrate using a second torroidal plasma controlling device, wherein the first torroidal path is not coincident to the second torroidal path; and    varying the plasma density in the vicinity of the substrate by amplitude modulating the first torroidal path of plasma at a first modulation pulsing frequency and a first RF power and modulation pulsing the second torroidal path of plasma at a second modulation pulsing frequency and a second RF power as a function of time.    
   
   
       11 . The method of  claim 10 , wherein the first modulation pulsing frequency and the second modulation pulsing frequency are between about 0.1 Hz and about 100,000 Hz.  
   
   
       12 . The method of  claim 10 , wherein the first RF power level and the second RF power level are between about 0 Watts and about 5000 Watts.  
   
   
       13 . The method of  claim 10 , wherein the ratio of the first RF power to the second RF power level is between about 1:1 and about 100:1.  
   
   
       14 . A method of processing a substrate in a plasma chamber, comprising: 
 generating a plasma over a surface of a substrate using a first plasma controlling device;    generating a plasma over a surface of the substrate using a second plasma controlling device, wherein the first plasma controlling device generates a plasma in a first region near the substrate and the second plasma controlling device generates a plasma in a second region near the substrate and the first and second regions overlap; and    varying the plasma density generated in the first region, in the second region, and a region between the first and second region by amplitude modulating the RF power delivered to the first plasma controlling device and the second plasma controlling device.    
   
   
       15 . The method of  claim 14 , wherein the first modulation pulse frequency and the second modulation pulse frequency are between about 0.1 Hz and about 100,000 Hz.  
   
   
       16 . The method of  claim 14 , wherein the first RF power level and the second RF power level are between about 0 Watts and about 5000 Watts.  
   
   
       17 . The method of  claim 14 , wherein the ratio of the first RF power to the second RF power is between about 1:1 and about 100:1.  
   
   
       18 . The method of  claim 14 , wherein the first plasma controlling device is a first inductive coil and the second plasma controlling device is a second inductive coil.  
   
   
       19 . The method of  claim 14 , wherein the first plasma controlling device is a first electrode and the second plasma controlling device is a second electrode.  
   
   
       20 . The method of  claim 14 , wherein the first plasma controlling device is a first torroidal source and the second plasma controlling device is a second torroidal source.  
   
   
       21 . A method of processing a substrate in a plasma chamber, comprising: 
 amplitude modulating the RF power to a first plasma controlling device at a first modulation pulse frequency and at a first power level;    amplitude modulating the RF power to a second plasma controlling device at a second modulation pulse frequency and at a second power level;    synchronizing the amplitude modulation of the RF power to the first plasma controlling device and the second plasma controlling device; and    varying the first and second modulation pulse frequencies to adjust the plasma density in a plasma chamber to compensate for a non-uniform area on a substrate surface.    
   
   
       22 . A method of processing a substrate in a plasma chamber, comprising: 
 amplitude modulating the RF power to a first plasma controlling device at a first modulation pulse frequency and at a first power level;    amplitude modulating the RF power to a second plasma controlling device at a second modulation pulse frequency and at a second power level;    synchronizing the amplitude modulation of the RF power to the first plasma controlling device and the second plasma controlling device; and    controlling the shape of the amplitude modulated RF power to the first and second plasma controlling devices, wherein the shape of the amplitude modulated RF power is rectangular, trapezoidal, triangular or sinusoidal.    
   
   
       23 . A method of processing a substrate in a plasma chamber, comprising: 
 amplitude modulating the RF power to a first plasma controlling device at a first modulation pulse frequency and at a first power level;    amplitude modulating the RF power to a second plasma controlling device at a second modulation pulse frequency and at a second power level;    synchronizing the amplitude modulation of the RF power to the first plasma controlling device and the second plasma controlling device,    controlling the shape of the amplitude modulated RF power to the first and second plasma controlling devices; and    controlling the overlap and/or gap between the amplitude modulated RF power to the first plasma controlling device and the second plasma controlling device.    
   
   
       24 . A method of processing a substrate in a plasma chamber, comprising: 
 amplitude modulating the RF power to a first plasma controlling device at a first modulation pulse frequency and at a first power level;    amplitude modulating the RF power to a second plasma controlling device at a second modulation pulse frequency and at a second power level;    synchronizing the amplitude modulation of the RF power to the first plasma controlling device and the second plasma controlling device,    controlling the amplitude modulation of the RF power to the first plasma controlling device and amplitude modulation of the RF power to the second plasma controlling device such that the power, modulation pulse frequency, modulation pulse duration, rest time between modulation pulses, and overlap of the modulation pulse to the first and/or second plasma controlling devices can be varied as a function of time.