Apparatus and method for controlling workpiece temperature

Abstract

An atmospheric controlled chamber includes a support assembly capable of holding a workpiece over a specific surface of the support assembly, a heat-transfer assembly located close to the support assembly and capable of transferring heat to and from the exterior of the chamber, and at least one thermopile device disposed in the support assembly. The thermopile device(s) is configured to transfer heat between the specific surface (or viewed as the held workpiece) and the heat-transfer assembly. A gas assembly is optionally surrounded by the chamber wall and capable of ensuring the existence and controlling the pressure of an essentially static gas between the held workpiece and the specific surface, wherein the gas is used as a thermal medium for conducting heat. The thermopile device acts as an efficient heat pump, so as to provide extra lower/higher workpiece temperature, a greater cooling/heating rates, and more flexible rate control.

1 . An atmospheric controlled chamber capable of controlling workpiece temperature, comprising:
 a chamber wall surrounding a space;   a support assembly located in the space and capable of holding a workpiece over a specific surface of the support assembly;   a heat-transfer assembly located close to the support assembly and capable of transferring heat to and from the exterior of the space; and   at least one thermopile device disposed in the support assembly, wherein the thermopile device is configured to transfer heat between the specific surface and the heat-transfer assembly.   
     
     
         2 . The atmospheric controlled chamber as set forth in  claim 1 , wherein the thermopile device is in series between the specific surface and the heat-transfer assembly. 
     
     
         3 . The atmospheric controlled chamber as set forth in  claim 1 , wherein the thermopile device almost contacts directly with the heat-transfer assembly. 
     
     
         4 . The atmospheric controlled chamber as set forth in  claim 1 , wherein a cold side of the thermopile device faces the specific surface and a hot side of the thermopile device faces the heat-transfer assembly, whereby the workpiece held by the support assembly can be cooled. 
     
     
         5 . The atmospheric controlled chamber as set forth in  claim 1 , wherein a hot side of the thermopile device faces the specific surface and a cold side of the thermopile device faces the heat-transfer assembly, whereby the workpiece held by the support assembly can be heated. 
     
     
         6 . The atmospheric controlled chamber as set forth in  claim 1 , wherein the thermopile device is a Peltier device including at least one p-type semiconductor element and at least one n-type semiconductor element connected in series and driven by a power supply. 
     
     
         7 . The atmospheric controlled chamber as set forth in  claim 6 , wherein the Peltier device is configured according to one or more of the following:
 the Peltier device being constructed so that heat can be pumped in both directions; and   two or more of the Peltier devices being installed in opposite direction pairs to pump heat in both directions.   
     
     
         8 . The atmospheric controlled chamber as set forth in  claim 1 , wherein the heat-transfer assembly is coupled with a chiller located outside the atmospheric controlled chamber, wherein the thermal mass of the thermopile device is significantly smaller than the thermal mass of a heat sink as a combination of at least the heat-transfer assembly and the chiller. 
     
     
         9 . The atmospheric controlled chamber as set forth in  claim 1 , further comprising a gas assembly at least partially surrounded by the chamber wall and capable of ensuring the existence of a gas below the held workpiece and above the specific surface, whereby the gas is used as a thermal medium between the held workpiece and the support assembly. 
     
     
         10 . The atmospheric controlled chamber as set forth in  claim 9 , the gas assembly being capable of controlling the pressure of the gas existing below the held workpiece and above the specific surface, whereby the heat transfer between the held workpiece and the specific surface is controllable. 
     
     
         11 . The atmospheric controlled chamber as set forth in  claim 9 , wherein the gas assembly is constructed according to at least one of the following:
 the gas assembly is connected to an external gas source outside the atmospheric controlled chamber; and   a portion of the gas assembly is embedded in the support assembly so that the gas is delivered through the support assembly onto the specific surface.   
     
     
         12 . The atmospheric controlled chamber as set forth in  claim 9 , wherein the support assembly is capable of clamping the workpiece tightly. 
     
     
         13 . The atmospheric controlled chamber as set forth in  claim 1 , further comprising a first pump configured to carry gas from a position away from the support assembly and to keep the space at a higher pressure and a second pump configured to carry gas from a position close to the specific surface and to keep a partial space between the support assembly and the held workpiece at a lower pressure, so that a pressure differential is distributed across the workpiece when the workpiece is held by the support assembly. 
     
     
         14 . The atmospheric controlled chamber as set forth in  claim 1 , wherein the support assembly has one or more electrodes located under the specific surface, and wherein the one or more electrodes is in series between the specific surface and the thermopile device. 
     
     
         15 . A method of controlling workpiece temperature, comprising:
 moving a workpiece from a first environment into a chamber, wherein the workpiece has a first workpiece temperature;   locating the workpiece over a top surface of a support assembly positioned inside the chamber, wherein a heat-transfer assembly is located close to the support assembly and capable of transferring heat to and from the exterior of the chamber, and wherein at least one thermopile device is disposed in the support assembly and is configured to transfer heat between the workpiece located on the top surface and the heat-transfer assembly;   adjusting the temperature of the workpiece in the chamber by using the thermopile device and the heat-transfer assembly simultaneously; and   moving the workpiece away from the chamber and into a second environment following the workpiece being adjusted to have a second workpiece temperature.   
     
     
         16 . The method as set forth in  claim 15 , wherein each of the first environment and second environment is chosen from one or more of the following:
 an atmospheric space;   a cassette;   a load lock chamber;   a main chamber configured to connect at least one load lock chamber and at least one process chamber where the workpiece is processed;   a chamber connected to the main chamber; and   a process chamber.   
     
     
         17 . The method as set forth in  claim 15 , further comprising temporarily turning off the thermopile device following the workpiece temperature being essentially equal to the second workpiece temperature and then turning on again the thermopile device following the workpiece temperature being different significantly than the second workpiece temperature. 
     
     
         18 . The method as set forth in  claim 15 , further comprising operating the thermopile device(s) with a maximum voltage to adjust the workpiece temperature as quickly as possibly until a desired workpiece temperature is about achieved, and then operating the thermopile device(s) with a continuous varied voltage in a conventional servo system type operation to maintain that workpiece temperature. 
     
     
         19 . The method as set forth in  claim 15 , further comprising moving the workpiece away from the thermopile device(s) when the workpiece reaches the desired temperature, so that the shortest temperature adjusting time is accomplished by setting both the heat-transfer assembly and the thermopile device(s) at their maximum lowest temperature, placing the workpiece on the support assembly for a prescribed time or until it reaches the desired temperature, then lifting the workpiece off the support assembly, the heat-transfer assembly and the thermopile device(s). 
     
     
         20 . The method as set forth in  claim 15 , further comprising providing the at least one thermopile device by using one or more Peltier device including at least one p-type semiconductor element and at least one n-type semiconductor element connected in series and driven by a power supply, and wherein two or more Peltier devices can be pumped in both directions and/or is installed in opposite direction pairs to enable pumping heat in both directions.