Positive Displacement Pumping Chamber

Abstract

A substrate processing system as illustrated at ( 1 ). A substrate ( 2 ) lies upon a piston ( 3 ) shown in both the loading position ( 3 a ) and in a processing position ( 3 b ). The substrate is loaded via a port ( 4 ) through a door ( 5 ). The loading area ( 7 a ), and/or the hole chamber ( 7 ) may be pumped out via a vacuum exhaust pipe ( 6 ) connected to a pump (not shown). A linear drive mechanism shown diagrammatically at ( 8 ) lifts the piston and the substrate in the chamber such that a process volume ( 7 b ) of the chamber is defined with poor gas conduction between the piston and the walls of the chamber.

1 . Apparatus for processing a substrate in a process cycle comprising: a chamber for receiving a substrate in a process volume and a movable wall displaceable to vary the process volume in accordance with the process cycle. 
   
   
       2 . Apparatus as claimed in  claim 1  including an exhaust outlet and wherein the movable wall can be moved to reduce the process volume to purge gas from the process volume through the exhaust outlet during a purge part of the process cycle. 
   
   
       3 . Apparatus as claimed in  claim 2  wherein there are a plurality of exhaust valves operable in respective purge parts of the process cycle. 
   
   
       4 . Apparatus as claimed in  claim 1  including an inlet for process gas and wherein the movable wall is movable to draw process gas through the inlet during a process part of the process cycle. 
   
   
       5 . Apparatus as claimed in  claim 4  wherein there are a plurality of inlet valves for respective process gases. 
   
   
       6 . Apparatus as claimed in  claim 1  including an inlet for purge gas. 
   
   
       7 . Apparatus as claimed in  claim 6  wherein the purge gas inlet is a process gas inlet. 
   
   
       8 . Apparatus as claimed in  claim 1  wherein the ratio of the largest and smallest process volumes defined by the movable wall is between about 5:1 and about 100:1. 
   
   
       9 . Apparatus as claimed in  claim 8  wherein the volume ratio is about 10:1. 
   
   
       10 . Apparatus as claimed in  claim 1  wherein the compression ratio in the process volume resulting from movement of the wall is between about 5:1 and about 100:1. 
   
   
       11 . Apparatus as claimed in  claim 10  wherein the compression ratio is about 10:1. 
   
   
       12 . Apparatus as claimed in  claim 1  wherein the movable wall acts as or carries a substrate support. 
   
   
       13 . Apparatus as claimed in  claim 12  wherein the movable wall is additionally movable between a substrate load/unload position and a process chamber defining position. 
   
   
       14 . Apparatus as claimed in any  claim 1  wherein the movable wall is located in an extension of the process chamber. 
   
   
       15 . Apparatus as claimed in  claim 14  wherein the chamber and the extension have a common housing. 
   
   
       16 . Apparatus as claimed in  claim 14  or  claim 15  wherein the extension is adjacent the chamber. 
   
   
       17 . Apparatus as claimed in  claim 1  including a substrate support and wherein the movable wall is generally opposite to the substrate support. 
   
   
       18 . Apparatus as claimed in  claim 17  further including a fixed housing extending around the substrate support to define a process chamber together with the removable wall and substrate support. 
   
   
       19 . Apparatus as claimed in  claim 17  or  claim 18  wherein the moveable wall and/or housing includes a plurality of parts at least two of which are relatively moveable to allow loading of a substrate onto the substrate support. 
   
   
       20 . Apparatus as claimed in any one of the preceding claims wherein the wall is a piston. 
   
   
       21 . A method of processing a substrate comprising: placing the substrate in a process volume and introducing a process gas or vapour into the process volume and/or subsequently removing gas or vapour from the volume wherein the step of introducing and/or removing the gas is at least partially performed by moving a movable wall to change the process volume in an appropriate sense. 
   
   
       22 . A method as claimed in  claim 21  wherein the steps of introducing and removing are sequentially repeated. 
   
   
       23 . A method as claimed in  claim 21  or  claim 22  wherein the process is chemical vapour deposition. 
   
   
       24 . A method as claimed in  claim 23  wherein the process is atomic layer deposition. 
   
   
       25 . A method as claimed in  claim 21  or  claim 22  wherein the process is dry etching. 
   
   
       26 . Apparatus as claimed in  claim 1  including a controller for operating the apparatus in accordance with the method of  claim 25 .