Gas Injection System For Chemical Vapor Deposition Using Sequenced Valves

Abstract

A gas injection system for a chemical vapor deposition system includes a gas manifold comprising a plurality of valves where each of the plurality of valves has an input that is coupled to a process gas source and an output for providing process gas. Each of a plurality of gas injectors has an input that is coupled to the output of one of the plurality of valves and an output that is positioned in one of a plurality of zones in a chemical vapor deposition reactor. A controller having a plurality of outputs where each of the plurality of outputs is coupled to a control input of one of the plurality of valves. The controller instructs at least some of the plurality of valves to open at predetermined times to provide a desired gas flow to each of the plurality of zones in the chemical vapor deposition reactor.

1 - 19 . (canceled) 
     
     
         20 . A method of gas injection into a chemical vapor deposition system, the method comprising:
 a) providing a process gas to inputs of a plurality of valves;   b) providing the process gas from outputs of the plurality of valves to a plurality of gas injectors positioned in a plurality of zones in a chemical vapor deposition reactor;   c) determining desired duty cycles for opening each of the plurality of valves that provide a desired amount of process gas to each of the plurality of zones in the chemical vapor deposition reactor; and   d) opening each of the plurality of valves for their desired duty cycle, thereby providing the desired amount of process gas to each of the plurality of zones in the chemical vapor deposition reactor for deposition.   
     
     
         21 . The method of  claim 20  wherein the process gas comprises an alkyl gas. 
     
     
         22 . The method of  claim 20  further comprising measuring at least one of growth rate and deposited film thickness during deposition. 
     
     
         23 . The method of  claim 22  wherein the measurements comprise in-situ reflection measurements. 
     
     
         24 . The method of  claim 20  further comprising measuring at least one of growth rate and deposited film thickness in at least two of the plurality of zones during deposition and adjusting a duty cycle for opening at least one of the plurality of valves in response to the measurements. 
     
     
         25 . The method of  claim 24  wherein the duty cycle is adjusted to improve the uniformity of the deposited film across at least two of the plurality of zones. 
     
     
         26 . The method of  claim 24  wherein at least one of the growth rate and the deposited film thickness is measured across the plurality of zones in a radial direction. 
     
     
         27 . The method of  claim 20  wherein the duty cycle for opening at least one of the plurality of valves is inversely proportional to a radius of the corresponding one of the plurality of zones. 
     
     
         28 . The method of  claim 20  wherein at least one of the plurality of valves is opened sequentially and at least one of the plurality of valves is continuously open during deposition. 
     
     
         29 . The method of  claim 20  wherein all of the plurality of valves are opened sequentially. 
     
     
         30 . The method of  claim 20  further comprising moving at least some of the plurality of gas injectors. 
     
     
         31 . The method of  claim 20  further comprising changing a dimension of an orifice of one of the plurality of gas injectors. 
     
     
         32 . The method of  claim 20  wherein a dimension of the orifice of one of the plurality of gas injectors is changed in response to at least one of a growth rate and a deposited film thickness measurement in at least one of the plurality of zones in the chemical vapor deposition reactor. 
     
     
         33 . A method of improving deposition rate uniformity in a chemical vapor deposition system, the method comprising:
 a) providing an alkyl process gas to inputs of a plurality of valves;   b) providing the alkyl process gas from outputs of the plurality of valves to a plurality of alkyl gas injectors positioned in a plurality of zones in a chemical vapor deposition reactor;   c) determining a duty cycle for opening at least one of the plurality of valves that provides an amount of alkyl process gas to a corresponding one of the plurality of alkyl gas injectors that improves deposition rate uniformity; and   a) opening at least one of the plurality of valves for the determined duty cycle, thereby providing an amount of alkyl process gas to at least one of the plurality of zones in the chemical vapor deposition reactor that improves deposition rate uniformity.   
     
     
         34 . The method of  claim 33  further comprising measuring at least one of growth rate and deposited film thickness in at least two of the plurality of zones during deposition and adjusting a duty cycle for opening at least one of the plurality of valves in response to the measurements to further improve the uniformity of the deposited film across at least two of the plurality of zones. 
     
     
         35 . The method of  claim 34  wherein the at least one of the growth rate and the deposited film thickness is measured across the plurality of zones in the radial direction. 
     
     
         36 . The method of  claim 33  wherein at least one of the plurality of valves is opened sequentially and at least one of the plurality of valves is continuously open during deposition. 
     
     
         37 . The method of  claim 33  wherein all of the plurality of valves are opened sequentially. 
     
     
         38 . The method of  claim 33  further comprising moving at least some of the plurality of gas injectors. 
     
     
         39 . The method of  claim 33  further comprising changing a dimension of an orifice of at least one of the plurality of gas injectors to improve uniformity.