Page 1 of 11
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`(cid:44)(cid:49)(cid:55)(cid:40)(cid:47) EXHIBIT 10(cid:24)(cid:26)
`
`

`

`US. Patent
`
`Sep. 4, 2001
`
`Sheet 1 0f 5
`
`US 6,284,110 B1
`
`I Electrically Charged I
`I Components
`
`24
`
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`
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`Conduit
`
`22
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`Liquid Supply
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`24
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`Page 2 of 11
`Page 2 of11
`
`

`

`US. Patent
`
`Sep. 4, 2001
`
`Sheet 2 0f 5
`
`US 6,284,110 B1
`
`
`
`FIG. 4
`
`FREQUENCY (MHz)
`
`Page 3 of 11
`Page 3 of11
`
`

`

`US. Patent
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`Page 5 of 11
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`US. Patent
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`Sep.4,2001
`
`Sheet4 0f5
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`US 6,284,110 B1
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`US. Patent
`
`Sep. 4, 2001
`
`Sheet 5 0f 5
`
`US 6,284,110 B1
`
`RF POWER
`IN
`
`i] 105
`
`)5”
`
`+ WATER
`
`
`Page 6 of 11
`Page 6 of11
`
`

`

`US 6,284,110 B1
`
`1
`METHOD AND APPARATUS FOR RADIO
`FREQUENCY ISOLATION OF LIQUID HEAT
`TRANSFER MEDIUM SUPPLY AND
`DISCHARGE LINES
`
`FIELD OF THE INVENTION
`
`The present invention pertains to radio frequency isola-
`tion to heat transfer supply and discharge lines through
`which electrically conductive heat transfer medium flows.
`More particularly, the present invention pertains to high-
`impedance heat transfer supply and discharge lines for use
`in sputtering and etching equipment used in the semicon—
`ductor industry.
`BACKGROUND OF THE INVENTION
`
`10
`
`15
`
`involves the
`Splitter coating is a coating process that
`transport of almost any material from a source, called the
`target, to a substrate of almost any material. The process
`takes place in a reduced pressure chamber containing argon
`or other process gas. The reduced pressure, or vacuum, is
`needed to increase the distance that the sputtered atoms can
`travel without undergoing collision with each other or with
`other particles. The argon gas is ionized which results in a
`bluish—purple glow of a plasma. Ejection of target source
`material
`is accomplished by bombardment of the target
`surface with gas ions that have been accelerated toward the
`target by a high voltage. As a result of momentum transfer
`between incident ion and target, particles of atomic dimen-
`sion are ejected from the target.
`'l‘hese ejected particles
`traverse the vacuum chamber and are subsequently depos-
`ited on a substrate as a thin film. A similar process is
`generally used in sputter etching, however,
`the target is
`replaced by the object to be etched.
`Radio frequency (RF) power, introduced into a process
`chamber via an inductive coil encircling the chamber, is
`often advantageously used in sputter coating and etching to
`enhance the development of the plasma. RI" sputter coating
`and etching allows the deposition of insulating as well as
`conductive materials and the etching of substrates, utilizing
`lower voltages, such as 500 to 2,500 V,
`to accelerate the
`argon gas ions to the target or substrate being etched. The
`lower voltage at the same power provides higher deposition
`and etching rates with reduced substrate damage.
`In
`addition, RF power may be used to bias the substrate to
`change the characteristics of film deposition, especially for
`insulating films. Such RI" power biasing of the substrate can
`improve adhesion and the added heat due to the bias power
`can provide higher mobility of source material on the
`substrate surface which can improve step coverage. Lower
`resistivity and changes in film stress can be obtained with RF
`voltage bias, as well. Gas incorporation into the film is
`usually increased. Oxide films such as silicon dioxide will
`have improved optical qualities and higher density when RF
`bias is used during deposition.
`Electronically isolating certain system components with
`respect to RF energization is desirable when using RF power
`in sputtering and etching. Otherwise,
`the plasma may be
`altered, adversely affecting the sputtering 0r etching process.
`In the case of RF biasing of the substrate,
`lack of RF
`isolation can result
`in undesired RF power dissipation.
`Consequently, it is desirable to RF isolate certain compo-
`nents within a sputtering or etching system. This RF isola—
`tion provides an interruption of a potential RF path to ground
`from the RF energized component.
`Another aspect of sputtering and etching systems is the
`requirement to thermally condition (heat or cool) certain
`
`30
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`45
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`60
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`Page 7 of 11
`Page 7 of11
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`
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`2
`system components or the substrate. This is usually accom—
`plished by circulating a liquid heat transfer medium in heat
`transfer relationship to the system component, or substrate
`support, as the case may be. As previously mentioned, the
`substrate may be biased by RF power for improved depo—
`sition or etching characteristics. Under such conditions, the
`heat transfer components must be electrically isolated from
`the RF applied to the substrate support. For example,
`in
`sputter coating target cooling is often desirable, whereas in
`sputter etching wafer cooling may be needed.
`In such
`situation, a liquid coolant is circulated through the susceptor
`or wafer support, as the case may be. In wafer processing
`configurations wherein an RF coil
`is placed around the
`sputtering or etching chamber to create and/or enhance the
`alasma,
`the RF coil has resistance that generates heat,
`requiring the RF coil to be cooled by circulating a liquid heat
`ransfer coolant medium through the RF coil. The heat
`ransfer component must be isolated from the RF applied to
`he RF coil.
`
`A problem arises when cooling an RI" coil and/or heating
`or cooling a substrate support or target holder as a result of
`he fact that the heat transfer media, usually water, in the
`ines used for circulating the heat transfer media through the
`coil or substrate support or target interferes with RF isolation
`of components such as the RF coil, substrate support, target
`iolder, etc. Maintaining the desired RF isolation while
`circulating a liquid heat
`transfer medium is required to
`3revent degradation of the sputtering 0r etching process.
`Water is typically used as the heat transfer liquid medium
`due to the safety, low cost, and ready availability of water.
`For example,
`in a simple open cooling system, cool tap
`water is supplied through a supply line to the sputtering or
`etching system component to be cooled at which place the
`water is circulated and thereafter discharged to a drain via a
`discharge line. Tap water typically contains dissolved min-
`erals that cause the water to be less chemically reactive to
`many materials. However, the dissolved minerals also create
`ions in the water that make the water electrically conductive,
`which can be disadvantageous when heating or cooling
`sputtering or etching system components energized with RF.
`Consequently, in many applications, the electrically conduc—
`tive tap water is first purified to remove the minerals, making
`it resistive. Resistive water is corrosive to many materials
`such as metals. As a consequence, a balance is sought in the
`level of water purification to achieve an acceptable level of
`conductivity versus corrosiveness.
`In addition, chemical
`additives are generally added to the water to mitigate the
`corrosive effects, incurring additional expense and inconve-
`nience in preparation and disposal of the liquid. These
`additives in some instances introduce detrimental effects
`such as reducing the resistivity of the water or decreasing the
`environmental safety of the liquid. Moreover, systems uti—
`lizing this type of component cooling or heating have to be
`designed to accommodate a certain amount of electrical
`power loss through the liquid heat transfer medium.
`Achieving the requisite balance in water purity involves
`the expense of buying or processing the water to the appro-
`priate purity level. Filtering and monitoring of the water is
`then required to maintain the purity within the acceptable
`range. Even with these additional requirements, there is still
`some degradation of performance and reliability of the
`components heated or cooled by the resistive water.
`Other relatively abundant and environmentally safe heat
`transfer liquids are also available; however, many of these
`are also electrically conductive, but by their nature cannot be
`processed to a more resistive condition and are thus inap-
`propriate for use.
`
`

`

`US 6,284,110 B1
`
`3
`Relying on the resistivity of the water to provide the RF
`isolation dictates that the water supply and discharge lines be
`increased in length, since the electrical resistance afforded
`by the water is a function of water path length to ground,
`assuming the resistivity of the water and diameter of the
`water lines are fixed. For example, typical resistive water
`cooling systems employ 12 to 13 feet of polypropylene
`tubing of about a quarter inch in outer diameter in each of
`the water supply and discharge lines to generate 1 M9 of
`resistance.
`
`Consequently, what is needed are high impedance liquid
`heat transfer medium supply and discharge lines that are not
`dependent principally upon the resistivity of the heat transfer
`liquid in isolating radio frequency energized components.
`SUMMARY OF THE INVENTION
`
`These and other needs are satisfied in accordance with
`certain principles of the present invention by a) coiling at
`least a portion of the liquid heat transfer medium supply
`and/or discharge lines such that
`the lines have a high
`inherent inductance and b) connecting a capacitive element
`in parallel with the coiled lines, with the capacitance being
`chosen such that the resonant frequency, and thus the highest
`impedance, of the coiled line /capacitor combination occurs
`at the RF frequency in use.
`The present invention, by virtue of being a passive device,
`requires no power source, and is less sensitive to variations
`in the electrical conductivity of the liquid, thus eliminating
`expensive liquid processing and filtering. Other advantages
`include reducing the length of liquid heat transfer medium
`supply and discharge lines normally employed.
`These and other objectives and advantages of the present
`invention will be more readily apparent from the following
`detailed description of the embodiments.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`10
`
`15
`
`30
`
`FIG. 1 is a block diagram of liquid cooled or heated
`system component having high impedance liquid heat trans-
`fer medium supply and discharge lines.
`FIG. 2 is an electrical schematic of the liquid cooled or
`heated system component of FIG. 1 wherein the high
`impedance liquid heat transfer medium lines are shown in
`both a fixed capacitance and variable capacitance embodi-
`ment.
`
`40
`
`45
`
`FIG. 3 is a diagrammatic perspective View of a fixed
`capacitance embodiment of a high impedance line of FIGS,
`1 and 2.
`
`FIG. 4 is a plot of impedance as a function of frequency
`for an illustrative embodiment.
`
`FIG. 5 is an equivalent electrical schematic of a high
`impedance line wherein the electrical resistance of the
`components is shown.
`FIG. 6 is a plot of the impedance and bandwidth of the
`high impedance line of FIG. 5 shown as a function of the
`resistance of the coil, illustrating that as DC resistance of the
`coil increases and/or resistance of an additional resistor in
`parallel to the coil increases, the peak impedance decreases
`and the bandwidth widens.
`
`FIG. 7 is a cross sectional depiction of a soft etching
`system utilizing liquid cooling of an RF coil and a wafer
`support, with the cooling supply and discharge lines appro—
`priate candidates for the high impedance lilies of this inven-
`tion.
`
`FIG. 8 is a depiction of the cooling line to the RF coil
`incorporating a high impedance conduit on the supply side.
`
`60
`
`65
`
`4
`FIG. 9 is a depiction of the cooling line to the wafer
`support, incorporating a high impedance conduit to both the
`supply and discharge sides.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`IVIG. I diagrammatically illustrates a thermally condi-
`tioned system 10 having a closed heat transfer system 12 for
`heating or cooling one or more electrically charged compo-
`nents 14. Aheat exchanger 16 brings a liquid heat exchange
`medium, such as water, into thermal and electrical contact
`with the electrically charged components 14. The heat
`exchanger 16, for example, may be metal tubing (not shown)
`placed in physical contact with the components 14 or in
`contact with a thermally conducting material (not shown)
`located between, and in heat transfer contact with, the tubing
`and the components 14. The closed heat transfer system 12
`has a liquid supply line 18, and a liquid return heat line 20,
`generally referred to as water lines. The liquid is processed
`and pressurized by a liquid supply 22. Interposed in the lines
`18, 20 are high impedance liquid conduits 24, 26 constructed
`in accordance with the principles of the invention.
`FIG. 2 shows an electrical schematic for the system 10 of
`FIG. 1. The electrically charged components 14 are shown
`as being electrified by a sinusoidal power supply 28 having
`an output v(f), where the frequency f is generally in the radio
`frequency (RF) band. The supply heat transfer medium line
`18 is shown having a known resistivity R1 and the return
`supply line 20 is shown having a known resistance R2, these
`values being a function of the resistivity of the liquid in the
`lines 18 and 20, the length and diameter of the lines 18, 20,
`and the resistivity of the material from which the lines 18
`and 20 are made
`
`The high impedance conduit 24 is shown as having an
`inductor Ll electrically in parallel with the parallel combi-
`nation of a fixed capacitor C1 and a trim capacitor Cr.
`Parallel capacitances are additive. Therefore, a small trim
`capacitor can adjust
`the equivalent capacitance for the
`overall capacitive element. Capacitors are electrical circuit
`elements used to store electrical charge temporarily, typi-
`cally comprising conductors separated by a dielectric.
`Consequently, capacitors C1 and C, contribute to electrical
`characteristics but not to fluid [low characteristics of the
`high impedance conduit 26.
`The return high impedance conduit 26 is shown as having
`an inductor I2 in parallel with a fixed capacitor C2. Both
`conduits 24, 26 are referenced to ground. The embodiments
`shown in FIG. 2 are exemplary and other embodiments are
`contemplated. For instance, a single variable capacitor could
`be used, or a plurality of fixed capacitors in parallel could be
`used, to achieve the desired equivalent capacitance.
`The resistance values of R1 and R2 would dictate the
`electrical power loss through the lilies 18, 20 but for the
`introduction of the high impedance conduits 24, 26.
`However, the contribution of the resistance values of R1 and
`R2 can be discounted as negligible as compared to the
`conduits 24, 26, which would have the equivalent imped-
`ance of:
`
`
`_ (2L *ZC)
`7
`WV _ 12!. +25)
`
`Where ZL is the impedance of an inductor (i.e., j2a'rfl ) and
`ZC is the impedance of the capacitor (i.e., 1/j23'rfC). This
`equivalent impedance quv is maximized at the reso-
`
`Page 8 of 11
`Page 8 of11
`
`

`

`US 6,284,110 B1
`
`5
`nant frequency fR the inductor%apacitor combination,
`which can be calculated as:
`
`fa =
`
`
`l
`r—
`27r\/ LC
`
`the
`In the illustrative embodiment shown in FIG. 3,
`adjustable high impedance conduit 26 is designed for the
`resonant frequency of 13.56 MHz, one of the standard
`frequency used in the industry exciting the argon gas in
`etching and sputter deposition systems. Lower frequencies,
`such as 450 kHz, are often used when exciting inductively
`couple plasmas The water line 20 may be of an electric
`insulative material tubing of about a quarter inch in outer
`diameter. The water line 20 is coiled into a five-turn coil L2
`of two inch outer diameter, resulting in an inductance value
`of about 1.0 mH. More turns for the coil 29 could be chosen
`to increase the impedance but this would trade off higher
`impedance for a narrower bandwidth of a high impedance
`region and would also increase the overall length of the coil
`29. An enclosure 44 surrounds the coil 29, providing pro—
`tection from physical damage to the coil 29. Preferably, the
`enclosure 44 would be a grounded Faraday RF shield, a
`conductive enclosure that protects internal components from
`external electromagnetic radiation and reduces emission of
`electromagnetic radiation from the coil 29 to the external
`environment. A capacitor C2 of 332 pF is operatively placed
`across the coil 29. Electrical connection between the liquid
`and the capacitor C2 could be achieved in numerous ways.
`For instance, an electrical conductor could be inserted
`through the water line 20. Also, the coil could have metal
`connectors at each end to aid in assembly and capacitor C2
`could contact these connectors. Preferably, the capacitor (32
`and connections to the coil 29 would be insulated. These
`inductance and capacitance values result in an impedance
`for the high-impedance conduit of over 30 M9, as shown in
`FIG. 4. This value compares to a requirement of 900 feet of
`water line 20 to achieve a comparable impedance if merely
`coiling the water line 20 without the capacitor C2.
`Referring to FIG. 5, an equivalent electrical schematic is
`shown for a high impedance conduit 30 wherein the elec-
`trical resistance of the components is considered. A first
`resistor R1, shown in series with coil 32, models the resis-
`tance of the coil 32 and liquid therein. For example, the coil
`32 may be of conductive material resulting in a low value for
`first resistor R1. Alternatively, the coil 32 may be of insu—
`lative material such that R1 results from the characteristics
`of the liquid, and thus R1 has a higher resistance value. A
`second resistor R2, in parallel to the series combination of
`the coil 32 and first resistor R1, represents an additional
`resistor added to a high impedance conduit 30 to control the
`peak impedance and bandwidth. The trimmable capacitor 34
`is shown in parallel with the series combination of the coil
`32 and first resistor R]. A second resistor R2 is shown in
`parallel to the series combination of the coil 32 and first
`resistor R1 and also in parallel to the trimmable capacitor 34.
`Second resistor R2 represents an additional resistor added to
`a high impedance conduit 30 to control the peak impedance
`and bandwidth, or accounts for resistance characteristics of
`trimmable capacitor 34.
`Consideration of the resistance of the coil 32 may be
`required, for example, in selecting an appropriate RF power
`supply (not shown) to a component in a sputtering or etching
`system, for instance, when the specific amount of electrical
`power dissipated by the heat transfer system 12 is critical. As
`another example, the frequency of the RF power supply may
`not be constant, thus dictating a wider operable bandwidth
`
`10
`
`15
`
`,
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`30
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`40
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`45
`
`60
`
`65
`
`6
`of the high impedance conduit 30. Consequently, the full
`electrical response of the heat transfer system 12 considering
`resistance provides a more accurate prediction. Design
`choice, such as choice of capacitive element 34 with appro-
`priate resistive characteristics, may be made for the desired
`peak impedance and width of band reject characteristics.
`Referring to FIG. 6, a plot of the impedance and band-
`width of the high impedance conduit 30 of FIG. 5, illustrat—
`ing that as DC resistance R1 of the coil 32 increases or the
`additional resistance of a second resistor R2, in parallel to
`coil 30, decreases, the peak impedance decreases and the
`bandwidth increases of the high impedance conduit 30.
`Referring to FIG. 7, a cross sectional depiction is shown
`of a soft etching system 50 utilizing water coolant heat
`transfer lines 52, 54 for a housing seal 56, and for a wafer
`support 58, respectively. An RF coil 60a for enhancing the
`plasma, shown encircling the bell jar vacuum process cham—
`ber 62, is water-cooled copper tubing, the copper providing
`an electrical conductor for the RF power, with the frequency
`of the RF power being 450 kHz. The RF coil 60a is a portion
`of a heat transfer line 60b shown and discussed below for
`HO. 8.
`A high vacuum is maintained within the enclosure 61
`formed by a bell jar vacuum process chamber 62 and
`aluminum housing 64, in part by an o-ring seal 66 between
`an aluminum support 68 and a stainless steel flange 70 of the
`aluminum housing 64, High vacuum is maintained at the
`contact between the bell jar 62 and the aluminum support 68
`by a high temperature VITON o-ring (not shown). To
`prevent thermal damage to the o-ring seal 66, cooling water
`is delivered to the support 68 by heat transfer line 52. Heat
`transfer line 52, however, is not an appropriate candidate for
`high impedance circuits since the line 52 is at ground
`potential.
`Heat transfer line 54 is an appropriate candidate for high
`impedance conduits since line 54 is near RF energized
`components.
`The wafer support 58 has an internal volume 72 open to
`atmospheric pressure through its downward opening 74. A
`silicon wafer 76 sets upon an RF energized table 78, the RF
`energy biasing the wafer 76, with the RF power supplied
`laving a frequency of 13.56 MHz.
`Wafer hold-down components 80 are similarly RF ener-
`gized and provide physical support to the quartz clamp 82
`aolding down the silicon wafer 76. The quartz clamp 82 is
`ield in position by support 84 beside the wafer receptacle
`58. The upper portion of wafer receptacale 58, the susceptor
`85, is raised to contact the clamp 82 and lowered to allow
`alacement of a wafer 76 on the table 78 by actuating the
`Jellows like lower portion 86 of the wafer receptacle 58.
`The table 78 has a downwardly extending thin flange 87,
`made thin to minimize heat loss from the top of the heated
`able 78 to the base 88 of the heated table 78, which provides
`whysical contact and support to the wafer hold-down com-
`aonents 80. The base 88 in turn is supported by a receptacle
`support 90, generally made of stainless steel, which for ease
`of manufacturing is shown composed of a plurality of
`components. Internal seals 92 are thus provided to prevent
`atmospheric pressure in the internal volume 72 from escap-
`ing to the enclosure 61. RF isolation between the RF
`energized base 88 and the receptacle support 90 is provided
`by ceramic flange 94. Seals 96 prevent atmospheric pressure
`from escaping past the ceramic flange 94. The bottom of the
`flange 87 of the heated table 78 is positioned near the
`ceramic flange 94 and its seals 96. The flange 87 is suscep-
`tible to damage due to heat as are the seals 96. Consequently,
`the cooling water line 54 is provided at this point.
`
`
`
`Page 9 of 11
`Page 9 of11
`
`

`

`US 6,284,110 B1
`
`7
`The importance of isolating RF power in the soft etching
`system 50 is shown by the addition of RF insulating ring 98,
`a portion of the receptacle support 90 in close non-touching
`proximity to the wafer hold-down components 80. The space
`between the RF insulating ring 98 and the wafer hold—down
`components 80 is so small as to form a dark space shield, a
`space too small
`to allow the formation of a plasma.
`Similarly,
`isolating heat
`transfer lines 52, 54, and 62 is
`necessary to prevent RF power from generating plasma, or
`otherwise conducting power to ground, at other locations.
`The soft etching system 50 is exemplary, with other
`sputter coating and sputter etching systems having heat
`transfer lines and RF powered components similarly being
`candidates for high impedance conduits.
`Referring to FIG. 8, the cooling line 60b to the RF coil
`60a is shown incorporating a high impedance conduit 100
`on the supply side 102. The cooling line 60b is energized by
`RF power as represented by capacitive coupling 103.
`Referring to FIG. 9, the cooling line 54 to the heated table
`78 is shown incorporating high impedance conduits 104,
`106 to both the supply side 108 and discharge side 110,
`respectively. The cooling line 54 is energized by RF power
`as represented by capacitive coupling 112.
`Although the embodiments described utilize passive
`capacitive elements to create a first-order notch filter,
`it
`would be further consistent with the invention to utilize
`active elements such as operational amplifiers. In addition,
`it would be further consistent with the invention to create
`higher—order notch filters or other filtering characteristics.
`For example,
`the sputtering or etching system may have
`components energized by an RF power source capable of
`varying the frequency of the RF power. Active components
`within a high impedance conduit can be employed to tune
`the impedance to correspond to the frequency of the RF
`power. In addition, the RF power present in the sputtering or
`etching system could have more than one frequency, such as
`the RF coil enhancing the plasma being at one frequency
`whereas RF bias to the substrate being at another frequency.
`Thus, a high impedance conduit could be provided with a
`broader bandwidth or with several notch filters tuned to
`these frequencies of interest such as with a higher order
`filter. Alternatively, a plurality of high impedance conduits,
`each blocking an RF frequency, could be placed in series to
`achieve a multiple notch or broader bandwidth high imped-
`ance.
`
`Moreover, although the capacitive element is shown as
`physically placed down the longitudinal axis of the coil,
`many orientations would be acceptable so long as the
`capacitive element is electrically in parallel with the coil.
`In addition, although the preferred embodiments as shown
`are used in cooling or heating components of sputtering
`systems, the invention is useful in chemical vapor deposition
`systems and ionized physical vapor deposition systems
`incorporating sources of RF energy.
`As described herein, open and closed system heat transfer
`systems 12 are appropriate for high impedance conduits. An
`open system includes having one liquid path, either the input
`to or the output from the device being cooled or heated,
`electrically isolated between the electrical power source and
`the device being cooled. As such,
`the high impedance
`conduit is omitted on that isolated liquid path. For example,
`tap water is pumped into a heat exchanger, requiring the high
`impedance conduit, whereas the output from the heat
`exchanger has such a long drain path through an insulating
`conduit that the resistivity of the cooling water is sufficient
`for electrical isolation. Alternatively, the output is discretely
`discharged in a fashion where no continuous short to ground
`exists.
`
`10
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`40
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`45
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`65
`
`8
`Those skilled in the art will appreciate that the imple—
`mentation of the present invention herein can be varied, and
`that the invention is described in preferred embodiments.
`For example, although a cooling system is described in
`detail, a high impedance conduit would be similarly
`employed for heating. Accordingly, additions and modifica-
`tions can be made, and details of various embodiments can
`be interchanged, without departing from the principles and
`intentions of the invention.
`What is claimed is:
`1. A high impedance liquid heat transfer medium conduit
`configured for a heat transfer system using heat exchange
`medium in thermal and electrical contact with a component
`to be thermally conditioned which is energized by radio
`frequency power of a predetermined frequency, the conduit
`comprising:
`a coiled liquid heat transfer medium line; and
`a capacitive element operatively connected in parallel
`with the coiled liquid heat transfer medium line, the
`coiled line and capacitive element collectively consti-
`tuting a parallel LC circuit resonant at a frequency
`approximating the predetermined frequency.
`2. The high impedance concuit of claim 1, wherein the
`heat exchange medium is water.
`3. The high impedance concuit of claim 1, wherein the
`capacitive element further comprises a variable capacitor
`such that the capacitance can be varied to tune the LC circuit
`to resonate at the predetermined frequency.
`4. The high impedance concuit of claim 3, wherein the
`variable capacitor includes a fixed capacitor in parallel with
`a trim capacitor.
`5. The high impedance concuit of claim 1, wherein the
`resonant frequency is approximately 13.56 MHz.
`6. The high impedance concuit of claim 1, wherein the
`resonant frequency is approximately 450 kllz.
`7. The high impedance conduit of claim 1, further com-
`prising a protective enclosure surrounding the coiled liquid
`heat transfer medium line and he capacitive element.
`8. The high impedance concuit of claim 1, wherein the
`capacitive element and the coiled liquid heat
`transfer
`medium line have a resonant frequency of approximately the
`predetermined frequency,
`9. The high impedance concuit of claim 1, wherein the
`components are incorporated in a semiconductor manufac-
`turing system.
`transfer medium
`10. The high impedance liquid heat
`conduit of claim 1, wherein the coiled liquid heat transfer
`medium line comprises an electrically insulating material.
`11. Ahigh impedance liquid heat transfer medium conduit
`configured for a heat transfer system using heat exchange
`medium in thermal and electrical contact with a component
`to be thermally conditioned which is energized by radio
`frequency power of a predetermined frequency, the conduit
`comprising:
`a coiled liquid heat transfer medium line, and
`a capacitive element operatively connected in parallel
`with the coiled liquid heat transfer medium line, the
`coiled line and capacitive element collectively consti-
`tuting a parallel LC circuit resonant at a frequency
`approximating the predetermined frequency; wherein
`the coiled line comprises a first coiled line configured
`to supply heat transfer liquid medium from a liquid
`supply to the component to be thermally-conditioned,
`the conduit further comprising:
`a second coiled liquid heat transfer medium line having
`an inherent inductance L when filled with a conduc-
`tive fluid used as a liquid heat transfer medium;
`
`
`
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`US 6,284,110 B1
`
`9
`a second capacitive element operatively connected in
`parallel with the second coiled liquid heat transfer
`medium line, the second capacitive element having a
`capacitance such that a resonant frequency of the
`second coiled liquid heat transfer medium line and
`the second capacitive element is approximately the
`predetermined frequency so that the conduit has a
`high impedance with respect
`to the components
`being thermally conditioned, minimizing electrical
`power loss,
`the second coiled liquid heat transfer
`medium line configured to be used to return liquid
`heat transfer medium to the liquid supply.
`12. The high impedance liquid heat
`transfer medium
`conduit of claim 11, wherein the first and second coiled
`liquid heat transfer medium lines comprise an electrically
`insulating material.
`13. A semiconductor wafer processing system compris-
`ing:
`a vacuum processing chamber;
`a thermally conditioned component selected from the
`group consisting of a wafer support, a sputter target
`support, a seal, a coil and a process gas distribution
`element;
`an RF supply operating at a predetermined frequency
`connected to energize said thermally conditioned com-
`ponent with RF energy;
`a high impedance liquid heat transfer medium conduit
`configured for a heat
`transfer system using heat
`exchange medium in thermal and electrical contact
`with said component to be thermally conditioned which
`is energized by radio frequency power of the predeter-
`mined frequency, the conduit comprising:
`a first coiled liquid heat transfer medium line connected
`between said component and a supply of liquid heat
`transfer medium, and
`a first capacitive element operatively connected in parallel
`with the coiled liquid heat transfer medium line, the
`coiled line and capacitive element collectively consti-
`tuting a parallel LC circuit resonant at a frequency
`approximating the predetermined frequency.
`14. The semiconductor wafer processing system of claim
`13, wherein the first coiled liquid heat transfer medium line
`comprises an electrically insulating material.
`15. A semiconductor wafer processing system compris—
`ing:
`a vacuum processing chamber;
`a thermally conditioned component selected from the
`group consisting of a wafer support, a splitter target
`support, a seal, a coil and a process gas distribution
`element;
`
`10
`an RF supply operating at a predetermined frequency
`connected to energize said thermally conditioned com-
`ponent with RF energy;
`a high impedance liquid heat transfer medium conduit
`configured for a heat
`transfer system using heat
`exchange medium in thermal and electrical contact
`with said component to be thermally conditioned which
`is energized by radio frequency power of the predeter-
`mined frequency, the conduit comprising:
`a first coiled liquid he at transfer medium line connected
`between