Semiconductor device fabricating system and semiconductor device fabricating method

Abstract

Shutoff valves are placed in parts of the process gas supply lines at positions near the processing vessel. A main purge gas supply line branches into branch purge gas supply lines, each of which is provided with an orifice called sonic nozzle. The branch purge gas supply lines are connected to parts of the process gas supply lines extending between the shutoff valves and the processing vessel. The ratio P1/P2, where P1 is primary pressure on the primary side of the orifice and P2 is secondary pressure on the secondary side of the orifice, is controlled to be not less than a predetermined value, for example, two, thereby, the purge gas can always be supplied at equal flow rates into the process gas supply lines. The total flow rate of the purge gas is controlled by a mass flow controller placed in the main purge gas supply line.

1 . A semiconductor device fabricating system comprising: 
 a processing vessel;    process gas supply lines each connected to the processing vessel to supply a process gas into the processing vessel;    shutoff valves each placed in each of the process gas supply lines at a position adjacent to the processing vessel;    a main purge gas supply line for carrying a purge gas;    branch purge gas supply lines branched from the main purge gas supply line, each of the branch purge gas supply lines being connected to a part of each of the process gas supply lines extending between the shutoff valve and the processing vessel;    a flow controller placed in the main purge gas supply line to control a sum of flow rates at which the purge gas flows through the branch purge gas supply lines; and    orifices each placed in each of the branch purge gas supply lines, each of the orifices being configured so that a flow rate of the purge gas flowing through the orifice is determined according to a primary pressure on a primary side of the orifice when pressure ratio P1/P2, where P1 is a primary pressure on the primary side of the orifice, and P2 is a secondary pressure on a secondary side of the orifice, is not smaller than a predetermined value.    
   
   
       2 . The semiconductor device fabricating system according to  claim 1 , wherein the flow controller comprises a mass flow controller.  
   
   
       3 . The semiconductor device fabricating system according to  claim 1 , wherein the flow controller includes a flow measuring device, and a pressure regulating device for regulating the primary pressure P1 on the primary side of the orifices based on a measured flow rate measured by the flow measuring device.  
   
   
       4 . The semiconductor device fabricating system according to  claim 1 , wherein the predetermined value is not less than two.  
   
   
       5 . A semiconductor device fabricating system comprising: 
 a processing vessel;    process gas supply lines each connected to the processing vessel to supply a process gas into the processing vessel;    shutoff valves each placed in each of the process gas supply lines at a position adjacent to the processing vessel;    a main purge gas supply line for carrying a purge gas;    branch purge gas supply lines branched from the main purge gas supply line, each of the branch purge gas supply lines being connected to a part of each of the process gas supply lines extending between the shutoff valve and the processing vessel; and    flow controllers each placed in the each of the branch purge gas supply lines to control a flow rate at which the purge gas flows through each of the branch purge gas lines.    
   
   
       6 . A semiconductor device fabricating method of processing a substrate by a predetermined process in a processing vessel to fabricate semiconductor devices on the substrate by using process gases supplied through process gas supply lines connected to the processing vessel, said semiconductor device fabricating method comprising: 
 supplying a purge gas through a main purge gas supply line and controlling the flow of the purge gas flowing through the main purge gas supply line;    distributing the purge gas flowing through the main purge gas supply line to a plurality of branch purge gas supply lines;    passing the purge gas distributed to the branch purge gas supply lines through orifices capable of determining, when pressure ratio P1/P2, where P1 is primary pressure on a primary side of the orifice and P2 is secondary pressure on a secondary side of the orifice, is not smaller than a predetermined value, a flow rate according to the primary pressure P1;    supplying the purge gas passed through the orifices to parts of the process gas supply lines extending between the processing vessel and shutoff valves placed in the process gas supply lines at positions adjacent to the processing vessel;    regulating pressure so that the pressure ratio P1/P2 is not smaller than a predetermined value; and    closing at least one of the shutoff valves placed in the process gas supply lines to purge the process gas remaining in a part of the process gas supply line provided with the closed shutoff valve extending below the closed shutoff valve by the purge gas passed through the orifice.    
   
   
       7 . A semiconductor device fabricating method of processing a substrate by a predetermined process in a processing vessel to fabricate semiconductor devices on the substrate by using process gases supplied through process gas supply lines connected to the processing vessel, said semiconductor device fabricating method comprising: 
 supplying a purge gas through a main purge gas supply line;    distributing the purge gas flowing through the main purge gas supply line to a plurality of branch purge gas supply lines;    controlling flow rates of the purge gas flowing through the branch purge gas supply lines by flow control means respectively placed in the branch purge gas supply lines;    supplying the purge gas distributed to the branch purge gas supply lines to parts of the process gas supply lines extending between the processing vessel and shutoff valves placed in the process gas supply lines at positions adjacent to the processing vessel, respectively; and    closing at least one of the shutoff valves placed in the process gas supply lines to purge the process gas remaining in a part of the process gas supply line provided with the closed shutoff valve extending below the closed shutoff valve by the purge gas passed through the branch purge gas supply line.