Temperature control of individual tools in a cluster tool system

A system for separately controlling the temperature of a number of controlled units using heat transfer fluid and comprising:

• a supply reservoir providing pressurized heat transfer fluid;
• a single refrigeration unit providing high pressure refrigerant;
• a number of conduit loops receiving refrigerant from the refrigeration unit and heat transfer fluid from the reservoir and each coupled to circulate heat transfer fluid through a different associated controlled unit, each of the conduit loops also including an evaporator receiving the refrigerant from the refrigeration unit and a heat exchanger for interchanging thermal energy between the heat transfer fluid and the refrigerant;
• servo control means for each of the conduit loops, each servo control means storing temperature values desired for the controlled units and including means for sensing the actual controlled unit temperature and providing a control signal to indicate a needed correction;
• and
• a number of proportional control valves, each disposed in a different conduit loop between the refrigeration unit and the evaporator for controlling refrigerant flow thereto in response to the control signals, to maintain the temperatures of the heat transfer fluid and the controlled units at desired levels.

A system occupying a low volume, but providing adequate refrigeration capacity and temperature control for individual tools having varying temperature maintenance requirements, while permitting convenient coupling and servicing, comprising the combination of:

• a rectangular open-sided frame;
• a single refrigeration unit mounted within the frame and having a refrigeration capacity substantially equal at a minimum to the maximum refrigeration demand of the tools, the refrigeration unit providing a refrigeration fluid output;
• a plurality of pump/motor combinations arrayed within the frame along adjacent horizontal axes, the pumps being collinear with the motors;
• a plurality of heat exchanger units disposed adjacent the pump/motor combinations within the frame, the heat exchanger units being coupled in temperature control loops to different ones of the pump/motor combinations and including heater means in at least some of the loops, the heat exchanger units comprising both a first type having means for cooling the heat transfer fluid only with an unchilled liquid, and a second type for cooling the heat transfer fluid with refrigeration fluid from the refrigeration unit, wherein the lowest temperature attainable is substantially below ambient;
• the heat exchanger units of the second type receiving refrigeration fluid in separate and parallel temperature control loops, each in thermal intercommunication with heat transfer fluid to be supplied to a different tool;
• a plurality of control means within the frame, each associated with a separate temperature control loop for controlling the temperature of the heat transfer fluid to a different tool, and providing the heat exchangers of the first type with an on/off binary-controlled flow of unchilled liquid, and providing heat exchangers of the second type with a proportional flow of expanded refrigeration fluid;
• and
• wherein the system further comprises a pressurized reservoir for heat transfer fluid and a pressurized reservoir for refrigeration fluid feeding the parallel temperature control loops.

In a system that provides heat transfer fluid to a number of tools in separate loops, to provide temperature control of the loops, a subsystem for enabling individual tools to be cleared of heat transfer fluid comprising:

• a single pressurized reservoir for the heat transfer fluid;
• a number of control loops for individual control systems for the different tools, the control loops including return ports and outlet ports, each having an associated flow control valve;
• a number of tool conduit systems, each for a different tool, and each including return and input lines for heat transfer fluid connectable to the return ports and outlet ports respectively of the control loops for the different tools, each tool conduit system including a low point below the tool;
• a number of purge gas inputs, each coupled to a different tool conduit system adjacent at least the low point therein;
• a source of pressurized gas available to be coupled to the purge inputs to the tool conduit systems;
• and
• at least one heat transfer fluid line, adapted to be coupled between the reservoir for pressurized heat transfer fluid and a chosen one of the tool conduit system, at the low point, whereby by coupling the source of purge gas to a purge gas input in a tool conduit system, heat transfer fluid is driven out of the tool conduit system toward the pressurized reservoir.

A temperature control unit for coupling to a cluster of semiconductor fabrication tools to control the temperature of each tool separately in accordance with an individual program for that tool, comprising:

• a number of temperature control channels, each including operative elements physically intermingled with elements from other channels, and each having a heat exchange loop coupled to a different fabrication tool, the channels each including a common coolant and a separate pressurizing pump for the coolant;
• a refrigeration system having a plurality of operative elements disposed in distributed relation among the temperature control channels, and including a refrigerant distribution and return system;
• a heat exchange system coupling the refrigerant distribution and return system to at least one of the heat exchange loops, the heat exchange system also being distributed among the elements of the temperature control channels;
• and
• the unit having all the operative elements thereof disposed within a volume of less than about two cubic feet per channel.