B/e Aerospace, Inc.

Advanced Thermal Sciences Corporation

Applied Materials, Inc.

William W Cowans

Kenneth Wesley Cowans

Glenn Zubillaga

Isaac Millan

Daniel John Hoffman

Douglas A Buchberger, Jr

Kallol Bera

Paul Brillhart

Richard Charles Fovell

Douglas H Burns

Hamid Tavassoli

Matthew Antoniou

Glenn W Zubillaga

Versatile temperature control systems adaptable to many different applications employ different states and proportions of a pressurized dual phase medium in direct contact with a thermal load. In one aspect of the invention, thermal energy generated by pressurization of a gaseous medium is stored at a selected temperature level so that it is later readily accessible. In addition, in accordance with the invention temperature control of a two-phase medium can be exercised across selectable dynamic ranges and with different resolutions. In accordance with such features, the control can be exerted by varying the input flow rate of a mixture applied to a thermal load, or by controlling the back pressure of the flow through the thermal load. In accordance with another feature of the invention, substantial energy conservation can be effected by employing an ambient temperature evaporator configuration between the thermal load and the input to the compressor. This variant also utilizes the two-phase characteristics of the medium. Moreover, the system can be configured compactly utilizing a thermal reservoir for retaining thermal energy for special purposes. In a food processing system for providing a frozen product, for example, the thermal reservoir can be accessed to utilize the refrigerant itself in different operating modes, such as rapid heating and system cleansing. In the food processing application, target temperatures can be set and maintained on a platen which is to receive food ingredients using energy flows at two different enthalpies, to enable rapid freezing or temperature elevation.

Temperature control system and method TDSF plus

In a temperature control system using a controlled mix of high temperature pressurized gas and a cooled vapor/liquid flow of the same medium to cool a thermal load to a target temperature in a high energy environment, particular advantages are obtained in precision and efficiency by passing at least a substantial percentage of the cooled vapor/liquid flow through the thermal load directly, and thereafter mixing the output with a portion of the pressurized gas flow. This 'post load mixing' approach increases the thermal transfer coefficient, improves control and facilities target temperature change. Ad added mixing between the cooled expanded flow and a lesser flow of pressurized gas also is used prior to the input to the thermal load. A further feature, termed a remote 'Line Box', enables transport of the separate flows of the two phase medium through a substantial spacing from pressurizing and condensing units without undesired liquefaction in the transport lines.

Method and apparatus for thermal exchange with two-phase media

A temperature control system is disclosed where thermal energy generated by pressurization of a gaseous medium is stored at a selected temperature level so that it is later readily accessible. Temperature control of a two-phase medium is exercised across selectable dynamic ranges and with different resolutions and the control can be exerted by varying the input flow rate of a mixture applied to a thermal load, or by controlling the back pressure of the flow through the thermal load.

A plasma reactor having a reactor chamber and an electrostatic chuck having a surface for holding a workpiece inside the chamber includes inner and outer zone backside gas pressure sources coupled to the electrostatic chuck for applying a thermally conductive gas under respective pressures to respective inner and outer zones of a workpiece-surface interface formed whenever a workpiece is held on the surface, and inner and outer evaporators inside respective inner and outer zones of the electrostatic chuck and a refrigeration loop having respective inner and cuter expansion valves for controlling flow of coolant through the inner and outer evaporators respectively. The reactor further includes inner and outer zone temperature sensors in inner and outer zones of the electrostatic chuck and a thermal model capable of simulating heat transfer through the inner and outer zones, respectively, between the evaporator and the surface based upon measurements from the inner and outer temperature sensors, respectively. Inner and outer zone agile control processors coupled to the thermal model govern the inner and outer zone backside gas pressure sources, respectively, in response to predictions from the model of changes in the respective pressures that would bring the temperatures measured by the inner and outer zone sensors, respectively, closer to a desired temperature.

Plasma reactor with a multiple zone thermal control feed forward control apparatus

A method of transferring heat from or to a workpiece support in an RF coupled plasma reactor includes placing coolant in an internal flow channel that is located inside the workpiece support and transferring heat from or to the coolant by circulating the coolant through a refrigeration loop in which the internal flow channel of the workpiece support constitutes an evaporator of the refrigeration loop. The method further includes maintaining thermal conditions of the coolant inside the evaporator within a range in which heat exchange between the workpiece support and the coolant is primarily or exclusively through the latent heat of vaporization of the coolant.

Method of cooling a wafer support at a uniform temperature in a capacitively coupled plasma reactor

A system for improving the thermal efficiency of a thermal control loop in which refrigerant after compression and condensation is applied to an evaporator employs a subsidiary counter-current heat exchange intercepting refrigerant flow to maintain the quality of the refrigerant by exchanging thermal energy between the input flow and the output flow from the evaporator. The same principle is effective, with particular advantage when small connections have to be made, in systems using mixed phase media and using the concept of direct energy transfer with saturated fluid.

Thermal control system and method

A method of controlling wafer temperature in a plasma reactor by obtaining the next scheduled change in RF heat load on the workpiece, and using thermal modeling to estimate respective changes in wafer backside gas pressure and in coolant flow through a wafer support pedestal that would compensate for the next scheduled change in RF heat load, and making the respective changes in the backside gas pressure or in the coolant flow prior to the time of the next scheduled change.

Method of processing a workpiece in a plasma reactor using multiple zone feed forward thermal control

A system and method for controlling cooling of a thermal load having different cooling requirements in different sections based on direct thermal exchange using a two-phase refrigerant employs the pressure/temperature characteristics of the refrigerant to particular benefit for this multi-level cooling system. The two-phase refrigerant is first adjusted to have temperature/enthalpy characteristics chosen as the starting level for different cooling demands at related temperatures. After appropriate generation of a mixture of two-phase refrigerant initial reference temperature and pressure are established. Thereafter, incremental changes in the comprising hot gas and expanded cooled liquid/vapor, an temperature cooling medium area made by lowering the pressure by predetermined amounts, or alternatively by bypassing the pressure drop and proceeding to the next stage.

System and method for thermal control of different heat loads from a single source of saturated fluids

A plasma reactor for processing a workpiece includes a reactor chamber, an electrostatic chuck within the chamber having a top surface for supporting a workpiece and having indentations in the top surface that form enclosed gas flow channels whenever covered by a workpiece resting on the top surface. The reactor further includes thermal control apparatus thermally coupled to the electrostatic chuck, an RF plasma bias power generator coupled to apply RF power to the electrostatic chuck, a pressurized gas supply of a thermally conductive gas, a controllable gas valve coupling the pressurized gas supply to the indentations to facilitate filling the channels with the thermally conductive gas for heat transfer between a backside of a workpiece and the electrostatic chuck at a heat transfer rate that is a function of the pressure against the backside of the workpiece of the thermally conductive gas. The reactor further includes an agile workpiece temperature control loop including (a) a temperature probe in the electrostatic chuck, and (b) a backside gas pressure controller coupled to an output of the temperature probe and responsive to a specified desired temperature, the controller governing the gas valve in response to a difference between the output of the temperature probe and the desired temperature.

Capacitively coupled plasma reactor having very agile wafer temperature control

A method of processing a workpiece in a plasma reactor having an electrostatic chuck for supporting the workpiece within a reactor chamber, the method including circulating a coolant through a refrigeration loop that includes an evaporator inside the electrostatic chuck, while pressurizing a workpiece-to-chuck interface with a thermally conductive gas, sensing conditions in the chamber including temperature near the workpiece and simulating heat flow through the electrostatic chuck in a thermal model of the chuck based upon the conditions. The method further includes obtaining the next scheduled change in RF heat load on the workpiece and using the model to estimate a change in thermal conditions of the coolant in the evaporator that would hold the temperature nearly constant by compensating for the next scheduled change in RF heat load, and making the change in thermal conditions of the coolant in the evaporator prior to the time of the next scheduled change by a head start related to the thermal propagation delay through the electrostatic chuck.

Method of processing a workpiece in a plasma reactor using feed forward thermal control

In a thermal control system of the type employing a two phase refrigerant that is first compressed and then is divided into a variable mass flow of refrigerant into a hot pressurized gas form and a differential remainder flow of cooled vapor derived from condensation and then thermal expansion, transitions between different temperature levels are enhanced by incremental variations of the mass flow at different control rates.

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Fullerton, CA, United States of America

William W Cowans