Chemical vapor deposition system with a plasma chamber having separate process gas and cleaning gas injection ports

Abstract

A method and arrangement for the insitu cleaning of a chamber in which process gas is injected into the chamber through gas injection ports. Separate gas injection ports through which process gas and the cleaning gas are injected into the chamber are provided. The process gas is injected into the chamber, such as a plasma chamber, through a first gas injection port while the cleaning gas, which cleans the residue left by the process gas during the deposition process, is injected into the chamber through the second gas injection port that is separate from the first gas injection port through which the process gas is injected. The separation of the gas injection ports provides an equalized pressure within the jet screw ports for the process gas and the interior of the chamber. This allows the jet screw ports to be maximally cleaned and reduces the frequency of replacement of the jet screw ports in the chamber.

What is claimed is:  
     
       1. A method of unclogging a first port in a vacuum chamber for processing workpieces, the first port injecting gas into the chamber, the method comprising the steps of: 
       terminating injection of the process gas into the chamber, then, while injection of the process gas into the chamber is terminated and the chamber remains in vacuo and the port is clogged, applying r.f. plasma excitation power to a structure including the first port while injecting cleaning gas into the chamber through a second opening separate from the first port to equalize pressure of the cleaning gas within the first port with pressure of the cleaning gas within the chamber. , the cleaning gas being converted to a plasma by r.f. plasma excitation power applied to it via the structure.  
     
     
       2. The method of  claim 1 , further comprising supplying energy into the chamber in the presence of the cleaning gas to generate ion bombardment, with the cleaning gas providing a cleaning agent that etches depositions in the chamber and the first port when the ion bombardment is generated. 
     
     
       3. The method of claim  2   1 , wherein the chamber has a chuck onto which wafers are placed, the method further comprising placing a cover wafer on the chuck prior to injecting the cleaning gas. 
     
     
       4. The method of  claim 3 , further comprising performing a deposition after the cleaning agent etches the deposits to getter the cleaning agent, followed by removing the cover wafer from the chamber. 
     
     
       5. The method of  claim 1  wherein the first port comprises a jet screw port. 
     
     
       6. A method of processing workpieces in a vacuum plasma processing chamber and cleaning the chamber while the workpieces are not being processed comprising 
       processing the workpieces in the chamber while the chamber is in vacuo by introducing a processing gas into the chamber through a first port and applying electric energy to the processing gas to establish a plasma that processes the workpiece, the processing gas having a tendency to form a residue that clogs the first port, the first port while clogged and while gas is applied to it establishing a high pressure region which resists the flow of gas through the first port into the chamber, and  
       while the workpieces are not being processed and the chamber remains in vacuo, applying, r.f. plasma excitation power to a structure including the first port while applying a cleaning gas to the chamber through a second port separate from the first port in such a manner that pressure is equalized at the first port and the cleaning gas unclogs the first port of the residue and cleans the remainder of the chamber.  
     
     
       7. The method of  claim 6  further comprising introducing a second processing gas into the chamber through the second port during vacuum plasma processing of the workpieces, the second processing gas being of a type that (a) does not have a tendency to form a residue in the second port and (b) reacts chemically with the first reaction gas. 
     
     
       8. The method of  claim 7  wherein the second processing gas includes argon and oxygen. 
     
     
       9. The method of  claim 8  wherein the first processing gas includes SiH 4  and the residue comprises SiO 2 . 
     
     
       10. The method of  claim 6  wherein gas is not introduced into the chamber through the second port during workpiece processing and further comprising introducing another reaction gas into the chamber via a third port during workpiece processing, the reaction gases introduced into the chamber via the first and third ports chemically reacting during workpiece processing. 
     
     
       11. The method of  claim 6  wherein no gas flows through the first port while the cleaning gas is applied to the chamber through the second port. 
     
     
       12. The method of  claim 6  wherein the first port comprises a jack screw. 
     
     
       13. The method of  claim 6  wherein the chamber includes a workpiece holder, and covering the workpiece holder while the cleaning gas is applied to the chamber via the cleaning port. 
     
     
       14. The method of  claim 6  wherein the cleaning gas is NF 3 . 
     
     
       15. The method of  claim 6  further including applying electric energy to the cleaning gas to establish a plasma that cleans the first port of the residue and the chamber. 
     
     
       16. The method of  claim 6  further comprising applying a getter to the chamber after the cleaning gas has been applied and before workpiece processing begins, the getter removing residual atoms of the cleaning gas from the chamber. 
     
     
       17. A method of cleaning a vacuum processing chamber between workpiece processing operations wherein the workpiece processing is performed by supplying processing gas to the chamber via a first port while the chamber is in vacuo, the processing gas having a tendency to leave a clogging residue in the first port, the chamber including a second port separate from the first port, the method comprising applying r.f. plasma excitation power to a structure including the first port while introducing a cleaning gas into the chamber via the second port while the chamber remains in vacuo and the processing gas is not supplied to the chamber so pressure is equalized at the first port and the cleaning gas cleans the first port of the clogging residue as well as the remainder of the chamber. , the cleaning gas being converted to a plasma by r.f. plasma excitation power applied to it via the structure.  
     
     
       18. The method of  claim 17  wherein the cleaning gas is NF 3 . 
     
     
       19. The method of  claim 18  further including applying electric energy to the cleaning gas to establish a plasma that cleans the first port of the residue and the chamber. 
     
     
       20. The method of  claim 17  further including applying electric energy to the cleaning gas to establish a plasma that cleans the first port of the residue and the chamber.