Gas supply unit, substrate processing apparatus, and supply gas setting method

Abstract

A gas supply unit, for supplying a gas into a processing chamber in which a substrate is processed, includes a plurality of gas supply sources, a mixing line for mixing a plurality of gases supplied from the gas supply sources to make a gaseous mixture, a multiplicity of branch lines for branching the gaseous mixture to be supplied to a multiplicity of places in the processing chamber, and an additional gas supply unit for supplying a specified additional gas to a gaseous mixture flowing in at least one branch line. The gas supply unit also includes pressure gauges and valves for adjusting gas flow rates in the branch lines, respectively, and a pressure ratio controller for controlling that gaseous mixtures branched into the branch lines to have a specified pressure ratio by adjusting opening degrees of the valves based on measurement results obtained by using the pressure gauges.

1 . A gas supply unit for supplying a gas into a processing chamber in which a substrate is processed, the gas supply unit comprising: 
 a plurality of gas supply sources;    a mixing line for mixing a plurality of gases supplied from the gas supply sources to make a gaseous mixture;    a multiplicity of branch lines for branching the gaseous mixture to be supplied to a multiplicity of places in the processing chamber; and    an additional gas supply unit for supplying a specified additional gas to a gaseous mixture flowing in at least one branch line.    
   
   
       2 . The gas supply unit of  claim 1 , further comprising pressure gauges and valves for adjusting gas flow rates in the branch lines, respectively, and a pressure ratio controller for controlling that gaseous mixtures branched into the branch lines to have a specified pressure ratio by adjusting opening degrees of the valves based on measurement results obtained by using the pressure gauges.  
   
   
       3 . The gas supply unit of  claim 2 , wherein the additional gas supply unit includes an additional gas supply line which communicates with said at least one branch line, and the additional gas supply line is connected to a downstream side of the pressure gauges and the valves.  
   
   
       4 . The gas supply unit of  claim 3 , wherein the pressure ratio controller controls that a pressure ratio of the gaseous mixtures branched into the branch lines becomes a specified pressure ratio by adjusting the valves under a condition in which the additional gas is not supplied to said at least one branch line from the additional gas supply unit, and opening degrees of the valves are fixed to values obtained under the condition.  
   
   
       5 . The gas supply unit of  claim 4 , further comprising a controller for supplying the additional gas to said at least one branch line from the additional gas supply unit after the gaseous mixtures branched into the branch lines are controlled to have a specified pressure ratio by the pressure ratio controller.  
   
   
       6 . A substrate processing apparatus, comprising: 
 a processing chamber accommodating therein a substrate;    a plurality of gas supply sources;    a mixing line for mixing a plurality of gases supplied from the gas supply sources to make a gaseous mixture;    a multiplicity of branch lines for branching the gaseous mixture to be supplied to a multiplicity of places in the processing chamber; and    an additional gas supply unit for supplying a specified additional gas to a gaseous mixture flowing in at least one branch line.    
   
   
       7 . The substrate processing apparatus of  claim 6 , further comprising pressure gauges and valves for adjusting gas flow rates in the branch lines, respectively, and a pressure ratio controller for controlling that gaseous mixtures branched into the branch lines to have a specified pressure ratio by adjusting opening degrees of the valves based on measurement results obtained by using the pressure gauges.  
   
   
       8 . The substrate processing apparatus of  claim 7 , wherein the additional gas supply unit includes an additional gas supply line which communicates with said at least one branch line, and the additional gas supply line is connected to a downstream side of the pressure gauges and the valves.  
   
   
       9 . The substrate processing apparatus of  claim 8 , wherein the pressure ratio controller controls that a pressure ratio of the gaseous mixtures branched into the branch lines becomes a specified pressure ratio by adjusting the valves under a condition in which the additional gas is not supplied to said at least one branch line from the additional gas supply unit, and opening degrees of the valves are fixed to values obtained under the condition.  
   
   
       10 . The substrate processing apparatus of  claim 9 , further comprising a controller for supplying the additional gas to said at least one branch line from the additional gas supply unit after the gaseous mixtures branched into the branch lines are controlled to have a specified pressure ratio by the pressure ratio controller.  
   
   
       11 . The substrate processing apparatus of  claim 6 , further comprising a shower head, disposed in the processing chamber, for discharging the gaseous mixture into a processing space in the processing chamber, wherein the branch lines are connected to the shower head.  
   
   
       12 . The substrate processing apparatus of  claim 11 , wherein the number of the branch lines is two and the two branch lines are respectively connected to a first and a second buffer space which are concentrically defined in the shower head.  
   
   
       13 . The substrate processing apparatus of  claim 12 , wherein the first and the second buffer space are respectively disposed at an inner portion and an outer portion in the shower head, and said at least one branch line connected to the additional gas supply unit is connected to the second buffer space.  
   
   
       14 . A supply gas setting method using the gas supply unit which includes: 
 a plurality of gas supply sources;    a mixing line for mixing a plurality of gases supplied from the gas supply sources to make a gaseous mixture;    a multiplicity of branch lines for branching the gaseous mixture to be supplied to a multiplicity of places in the processing chamber;    an additional gas supply unit for supplying a specified additional gas to a gaseous mixture flowing in at least one branch line; and    valves and pressure gauges for adjusting gas flow rates in the branch lines, respectively,    the method comprising the following sequential steps of:    controlling a pressure ratio of the gaseous mixtures branched into the branch lines to be a specified pressure ratio by adjusting the valves under a condition in which the additional gas is not supplied to said at least one branch line from the additional gas supply unit and, then, fixing opening degrees of the valves of the branch lines to values obtained under the condition; and    supplying an additional gas of a specified flow rate to said at least one branch line from the additional gas supply unit.