Heat tuner for heating substrates in a processing tool

Abstract

One example provides a heat tuner for transferring heat to a substrate in a processing tool. The heat tuner comprises a body comprising a substrate side and a substrate holder side. The substrate side is configured to support the substrate. The substrate holder side is configured to receive heat from a heater of a substrate holder. The heat tuner further comprises one or more contact features configured to support the body above the substrate holder to form a gap between the body and the substrate holder. The body comprises a thermally conductive material configured to distribute the heat received at the substrate holder side at least partially across the substrate side.

Description

HEAT TUNER FOR HEATING SUBSTRATES IN A PROCESSING TOOLBACKGROUND

[0001] Semiconductor device fabrication processes involve many steps of material deposition, patterning, and removal to form integrated circuits on substrates. Example deposition processes include chemical vapor deposition (CVD) and atomic layer deposition (ALD). CVD forms a film on a substrate by exposing a substrate in a processing chamber to a continuous flow of one or more reactants under conditions that cause the reactants to form a desired film on the substrate. ALD forms a film in a layer by layer manner. Each film layer is formed in an ALD cycle. Each ALD cycle includes adsorbing a film precursor to a surface of a substrate in a processing chamber, purging excess film precursor from the processing chamber, and then exposing the adsorbed precursor to a reactant to form the film layer.

[0002] Thermal energy can be used to help drive the reactions that form films in CVD and ALD processes. Thermal energy can be provided to a substrate by a substrate heater integrated with a substrate holder of a processing tool.SUMMARY

[0003] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.

[0004] One example provides a heat tuner for transferring heat to a substrate in a processing tool. The heat tuner comprises a body comprising a substrate side and a substrate holder side. The substrate side is configured to support the substrate. The substrate holder side is configured to receive heat from a heater of a substrate holder. The heat tuner further comprises one or more contact features configured to support the body above the substrate holder to form a gap between the body and the substrate holder. The body further comprises a thermally conductive material configured to distribute the heat received at the substrate holder side at least partially across the substrate side.

[0005] In some such examples, each contact feature of the one or more contact features alternatively or additionally is located at a radial distance closer to an outer edge of the substrate holder side than a center of the substrate holder side.

[0006] In some such examples, each contact feature alternatively or additionally is located at a radial location greater than a radius of a substrate contact area of the substrate side.

[0007] In some such examples, the substrate holder side alternatively or additionally comprises a planar surface.

[0008] In some such examples, the substrate holder side alternatively or additionally comprises a non-planar surface configured to vary a distance of the gap as a function of location.

[0009] In some such examples, the heat tuner alternatively or additionally comprises an optical layer on at least a portion of the substrate holder side. The optical layer has one or more optical properties with respect to infrared (IR) radiation that are different than the thermally conductive material. The one or more optical properties comprise one or more of absorbance, reflectivity, or transmittance.

[0010] In some such examples, the thermally conductive material alternatively or additionally comprises aluminum.

[0011] Another example provides a processing tool comprising a processing chamber and a substrate holder located within the processing chamber. The substrate holder comprises a heater. The processing tool further comprises a heat tuner comprising a body. The body of the heat tuner comprises a substrate side and a substrate holder side. The substrate holder side is configured to receive heat from the heater. The body further comprises a thermally conductive material configured to distribute the heat received at the substrate holder side at least partially across the substrate side.

[0012] In some such examples, the heat tuner alternatively or additionally comprises one or more contact features that support the body above the substrate holder to form a gap between the body and the substrate holder.

[0013] In some such examples, each contact feature alternatively or additionally is located at a radial location greater than a radius of a substrate contact area of the substrate side.

[0014] In some such examples, the substrate holder side alternatively or additionally comprises a non-planar surface configured to vary a distance of the gap as a function of location.

[0015] In some such examples, the substrate holder side alternatively or additionally comprises a planar surface.

[0016] In some such examples, the heat tuner alternatively or additionally comprises an optical layer on at least a portion of the substrate holder side. The optical layer has one or more optical properties with respect to infrared (IR) radiation that are different than the thermally conductive material. The one or more optical properties comprise one or more of absorbance, reflectivity, or transmittance.

[0017] In some such examples, the thermally conductive material alternatively or additionally comprises aluminum.

[0018] In some such examples, the processing tool alternatively or additionally comprises a gas delivery system configured to control a pressure of the processing chamber in a range of 30 torr to 120 torr.

[0019] Another example provides a method for using a heat tuner in a processing chamber of a processing tool. The heat tuner comprises a body with a substrate side, a substrate holder side, and contact features that support the body above a heater of a substrate holder to form a gap between the substrate holder and the body. The method comprises placing a substrate on the heat tuner in the processing chamber, providing power to the heater of the substrate holder to heat the substrate holder, and transferring at least some of the heat from the heater to the substrate holder side of the heat tuner by using one or more of radiation or gas gap conduction through the gap to thereby heat the substrate.

[0020] In some such examples, heating the substrate alternatively or additionally comprises distributing at least some of the heat from the substrate holder side of the heat tuner at least partially across the substrate side by thermally conducting the heat through the body of the heat tuner.

[0021] In some such examples, the method alternatively or additionally comprises reflecting some of the radiation with an optical layer on at least a portion of the substrate holder side of the heat tuner.

[0022] In some such examples, transferring the at least some of the heat from the heater to the substrate holder side of the heat tuner using the gas gap conduction alternatively or additionally comprises transferring the heat using gas in the gap.

[0023] In some such examples, the method alternatively or additionally comprises replacing the heat tuner when the heat tuner meets a replacement threshold condition.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 schematically illustrates an example processing tool in the form of a thermal CVD processing tool.

[0025] FIG. 2 schematically depicts an example heat tuner within a processing chamber.

[0026] FIG. 3 shows measured temperature variation on a substrate for a two- zone substrate heater as a function of heater power ratios obtained with and without an example heat tuner.

[0027] FIG. 4 schematically depicts an example heat tuner comprising an optical layer.

[0028] FIG. 5 schematically depicts an example heat tuner utilizing a non- planar surface to vary a gap.

[0029] FIG. 6 schematically depicts an example heat tuner with a body that comprises a plurality of materials with different thermal conductivities.

[0030] FIG. 7 illustrates an example method for using a heat tuner to transfer heat to a substrate in a processing tool.DETAILED DESCRIPTION

[0031] The term “atomic layer deposition” (ALD) generally represents a process in which a film (e.g., an oxide film) is formed on a substrate in one or more individual layers by sequentially adsorbing a precursor conformally to the substrate and reacting the adsorbed precursor to form a film layer. Thermal ALD (TALD) utilizes heat to facilitate a chemical conversion of the precursor adsorbed to the substrate. The terms “growth” and “deposition”, and variants thereof, also may be used to refer to film formation.

[0032] The term “body” generally represents a physical mass of a heat tuner.

[0033] The term “chemical vapor deposition” (CVD) generally represents a process in which a film is formed on a substrate by exposing the substrate to a continuous flow of one or more vapor phase precursors under conditions configured to convert the one or more precursors to the film on the substrate.

[0034] The term “contact feature” generally represents a physical structure configured to support a body of a heat tuner over a substrate holder.

[0035] The term “etch” and variants thereof generally represent removal of material from a substrate.

[0036] The term “gap” generally represents a volume of space formed between a body of a heat tuner and a substrate holder. Gas particles in the gap can perform gas gap conduction of heat. More particularly, the gas particles collide with top and bottom surfaces of the volume of space, along with each other, to transfer thermal energy.

[0037] The term “heat” generally represents thermal energy.

[0038] The term “heat tuner” generally represents a device that supports a substrate over a substrate holder and that transfers heat produced by a heater of the substrate holder to the substrate to achieve a different substrate temperature profile compared to a temperature profile of the substrate resting directly on the substrate holder.

[0039] The term "substrate holder side” generally represents a surface of a heat tuner configured to face a substrate holder.

[0040] The term “optical layer” generally represents a coating on a heat tuner having different optical properties with respect to infrared (IR) radiation than a material of a body of the heat tuner. Example optical properties include absorbance, reflectivity, and transmittance.

[0041] The term “processing chamber” generally represents an enclosure in which processing is performed on substrates. The pressure, temperature, atmospheric composition, and other conditions within a processing chamber are controllable during substrate processing.

[0042] The term “processing tool” generally represents a machine including a processing chamber and other hardware configured to enable processes to be carried out in the processing chamber.

[0043] The term “substrate” generally represents any object that can be processed in a processing tool.

[0044] The term “substrate contact area” generally represents a region on a substrate side of a heat tuner that is configured to be positioned beneath a substrate during processing.

[0045] The term "substrate temperature profile” generally represents temperature of a substrate as a function of location on the substrate. Uniformity of the substrate temperature profile can be measured as a range of temperatures in the substrate temperature profile.

[0046] The term “substrate holder” generally represents any structure configured to support a substrate in a processing chamber during processing.

[0047] The term "substrate side” generally represents a surface of a heat tuner that faces a substrate during substrate processing.

[0048] As mentioned above, chemical vapor deposition (CVD) forms a film by exposing a substrate to a continuous flow of one or more film precursors under conditions configured to cause the one or more precursors to chemically react and form the film on the substrate. Various types of energy can drive the reaction(s) that form the film. For example, plasma enhanced CVD (PECVD) uses a plasma to provide energy to drive the reaction(s) that form the film. Thermal CVD uses thermal energy in the absence of a plasma to drive the reaction(s) that form the film.

[0049] The rate of film formation in a CVD process can be dependent upon substrate temperature. For example, a temperature of the substrate can affect the adsorption of reactants to the substrate surface during film formation. As such, a film may have different deposition rates at different temperatures.

[0050] A thermal CVD processing tool can use a heater integrated into a substrate holder to heat a substrate. However, such a heater can have nonuniformities in thermal output as a function of location that can result in nonuniform substrate temperature profiles at the substrate surface. Such nonuniformities can result, for example, from geometries of the heater (e.g., heater coil spacing), and / or the substrate holder, (e.g., heater connection hardware). Nonuniform substrate temperature profiles can lead to nonuniform film growth on the substrate. This can potentially impact manufacturing yields. Further, developing, producing and installing new substrate holders to adjust substrate temperature profiles can be time-consuming and expensive.

[0051] Accordingly, examples are disclosed that relate to heat tuners for transferring and redistributing heat from a substrate holder heater to a substrate in a processing tool. Briefly, a heat tuner comprises a body and contact features. The contact features are configured to support the body above a substrate holder to form a gap between the body and the substrate holder. The gap helps to at least partially isolate the heat tuner from a heater geometry integrated in the substrate holder. Heat is transferred to the heat tuner body from the substrate heater primarily by infrared (IR) radiation and gas gap conduction. The body of the heat tuner comprises a substrate side configured to support a substrate. The body also comprises a substrate holder side configured to receive heat from a heater of the substrate holder. The body further comprises a thermally conductive material configured to distribute the heat received at the substrate holder side at least partially across the substrate side. As discussed in more detail below,the heat tuner can help to provide a more uniform substrate temperature profile than another substrate temperature profile at a substrate disposed on the substrate holder without the heat tuner. Further, in some examples a heat tuner also can be designed to achieve a desired non-uniform temperature profile. The disclosed heat tuners are less expensive to design and manufacture than a substrate holder with an integrated heater. This allows different heat tuners to be switched out to achieve different substrate temperature profiles in a same processing tool.

[0052] Before discussing an example heat tuner in more detail, FIG. 1 schematically shows an example processing tool 100 in the form of a thermal CVD processing tool. Processing tool 100 comprises a heat tuner 102 disposed on a substrate holder 104 within a processing chamber 106. Heat tuner 102 is configured to support and heat a substrate 108 disposed within processing chamber 106. Therefore, heat tuner 102 comprises a body and contact features configured to support the body above substrate holder 104 to form a gap 110. Heat tuner 102 receives at least some heat from a heater 112 integrated in substrate holder 104 using radiation and / or gas gap conduction through gap 110. Further, heat tuner 102 distributes the heat received to thereby heat substrate 108 by using thermal conduction through the body. An example heat tuner and corresponding heat transfer are discussed in more detail with reference to FIG. 2. In such a manner, heat tuner 102 can help to provide a specified substrate temperature profile at substrate 108. As one example, heat tuner 102 can help to provide a more uniform substrate temperature profile than a substrate temperature profile at a substrate arranged on substrate holder 104 without heat tuner 102. This may help to at least partially mitigate an unsuitably nonuniform heat profile of heater 112. As another example, heat tuner 102 can help to provide temperatures at substrate 108 lower than a lowest controllable temperature that heater 112 can provide. In such examples, heat tuner 102 can act as a thermal resistor.

[0053] Processing tool 100 further comprises flow control hardware 114 connecting one or more processing chemical source(s) 116 to processing chamber 106. Flow control hardware 114 can include any suitable components, such as mass flow controllers, valves, and / or conduits, for example. Further, processing tool 100 comprises a processing chemical inlet 118 configured to introduce processing chemicals into processing chamber 106. While processing chemical inlet 118 is depicted as a showerhead, in other examples, a processing tool can comprise a nozzleor other suitable inlet hardware as opposed to or in addition to processing chemical inlet 118.

[0054] Processing tool 100 further comprises an exhaust system 120. Exhaust system 120 is configured to exhaust gases from processing chamber 106. Exhaust system 120 can comprise any suitable hardware, including one or more low vacuum pumps, one or more high vacuum pumps, and one or more valves for controlling an exhaust flow. Flow control hardware 114 and exhaust system 120 operate together as a gas delivery system configured to control a pressure of processing chamber 106 during processing of substrate 108. Example pressures include pressures in a range of 10 Torr to 120 Torr.

[0055] Processing tool 100 further comprises a controller 122 configured to control various operations of processing tool 100. Here, controller 122 is operatively coupled to heater 112, flow control hardware 114, and exhaust system 120. For example, controller 122 is configured to control processing tool 100 to operate heater 112 to generate heat for a process. Controller 122 also is configured to operate flow control hardware 114 to flow a selected processing chemical or mixture of processing chemicals at a selected rate into processing chamber 106. Controller 122 is further configured to operate exhaust system 120 to remove gases from processing chamber 106. Controller 122 can comprise any suitable computing system. While discussed herein with reference to a thermal CVD processing tool, heat tuner 102 can be used in any other suitable non-plasma processing tool. Examples include ALD tools and etching tools.

[0056] FIG. 2 schematically depicts an example heat tuner 200 in a processing chamber 202. Processing chamber 202 can be used in any suitable processing tool, such as processing tool 100, for example. As depicted, heat tuner 200 is arranged on a substrate holder 204 located within processing chamber 202. Substrate holder 204 comprises a heater 206.

[0057] Heat tuner 200 comprises a body 208 comprising a substrate side 208a. Substrate side 208a is configured to support a substrate 212 in a substrate contact area 214. Body 208 also comprises a substrate holder side 208b configured to receive heat from heater 206. Body 208 is at least partially formed from a thermally conductive material configured to distribute heat received at substrate holder side 208b at least partially across substrate side 208a by thermal conduction. The thermally conductive material can be selected based on process requirements, such as resistance to processingchemicals (including materials used for plasma cleaning processes, such as fluorine- containing materials) and intended process temperature ranges. In some examples, the thermally conductive material can comprise aluminum, anodized aluminum, an aluminum alloy, aluminum oxide, aluminum nitride, yttrium oxide, combinations thereof, and / or one or more other suitable ceramic or metallic materials. In some examples, the heat tuner can be coated with a protective coating. For example, an aluminum heat tuner can be coated with one or more layers of aluminum oxide and / or yttrium oxide. In various examples, the thermally conductive material can be electrically conductive or dielectric.

[0058] Heat tuner 200 further comprises a plurality of contact features 218 configured to support body 208 above substrate holder 204 to form a gap 220 between body 208 and substrate holder 204. Gap 220 helps to at least partially isolate heat tuner 200 from a geometry of heater 206. In various examples, one or more sides of gap 220 can be enclosed, partially enclosed, open, or any suitable combination thereof.

[0059] Some heat from heater 206 is transferred to substrate holder side 208b using gas gap conduction through gap 220. Other heat is transferred radiatively across gap 220. The amount of heat transferred to heat tuner 200 by gas gap conduction is based at least in part on a distance across gap 220, a type or types of gas(es) within gap 220, and density of the gas within gap 220. For example, the gas gap conduction is proportional to a collision rate of the gas molecules with each other and with the walls around them (e.g., top, bottom, and / or side walls), such as collisions with substrate holder 204 and heat tuner 200, for example. In some examples, the gas within gap 220 are process gases within processing chamber 202. In other examples, a substrate holder can comprise gas outlets configured to introduce a tuning gas into gap 220. Example tuning gases include helium gas, hydrogen gas, argon gas, and mixtures therefrom. A more specific example comprises a mixture of 10% helium and 90% nitrogen. In such a manner, the distance across gap 220 and the gas in gap 220 can help to provide specified heat transferred using gas gap conduction between substrate holder 204 and substrate holder side 208b. Furter, depending on the gas in gap 220, some heat can transfer to substrate holder side 208b using convective heat transfer. More particularly, gases having a sufficient temperature, flow rate, and thermal properties can flow between heat tuner 200 and substrate holder 204. In some examples, the convective heat transfer may be larger at higher pressures than lower pressures (e.g., more heat may be transferred at 50 Torr than at 2 Torr).

[0060] The amount of heat transferred radiatively is a function of the inverse of the square of the distance of gap 220. Radiative heat transfer also is based on optical properties of heat tuner 200 at substrate holder side 208b, such as IR absorbance, reflectivity, and transmittance. In some examples, a heat tuner can comprise an optical layer on a substrate holder side to help achieve desired IR absorption, reflection, and / or transmission properties, as discussed with reference to FIG. 4.

[0061] Depending upon a configuration of a heat tuner, some heat from a heater can be transferred to a body of a heat tuner by thermal conduction through a contact area between contact features and a substrate holder. This thermal conduction can result in thermal hotspots in a substrate temperature profile at a substrate. As such, in the depicted example each contact feature of the plurality of contact features 218 is located at a radial location greater than a radius of substrate contact area 214 of substrate side 208a. This can help to reduce an amount of heat transferred to the substrate by undesired thermal conduction through the contact features. Further, a heat tuner can be configured to have a small total area of contact with a substrate holder compared to a total area of the heat tuner. This can help to support the heat tuner above the substrate holder while also minimizing thermal conduction. In some examples, the plurality of contact features 218 can comprise three pins arranged in a triangle formation. In other examples, a plurality of contact features can have another configuration to modulate the heat transfer in a different manner. In some such examples, the plurality of contact features can include more than three contact points, and / or a non-planar contact surface that is in partial contact with the substrate holder. In further examples, plurality of contact features 218 can be omitted and thus, substrate holder side 208b may be in substantially continuous contact with substrate holder 204 over a total surface area of holder side 208b.

[0062] In the depicted example, substrate holder side 208b comprises a planar surface to form a substantially uniform distance across gap 220. The term “substantially” refers to variations in the distance of the gap 220 due to surface roughness that deviates from the average plane of substrate holder side 208b. Such a configuration helps to enable uniform gas gap conduction across substrate holder side 208b. In other examples, a substrate holder side 208b can comprise a non-planar surface, as discussed with reference to FIG. 5.

[0063] As mentioned above, heat tuner 200 can be easily removed from a processing chamber and replaced with a different heat tuner. This enables heat tuner200 to be easily replaced with a heat tuner of a same design at an end of life, and / or to be exchanged with a heat tuner of a different design. Substrate holder 204 can be lowered to accommodate heat tuner 200. This allows a desired spacing of substrate 212 from a showerhead to be maintained. This also places substrate side 208a at a transfer plane of the existing processing chamber. While not depicted, heat tuner 200 can include openings to accommodate lift pins of substrate holder 204.

[0064] Heat tuner 200 can be manufactured using any suitable method. For example, a metal heat tuner 200 (e.g., aluminum) can be machined or cast. A ceramic heat tuner 200 (e.g., aluminum nitride) can be formed using additive manufacturing, molding / sintering / annealing, or other ceramic manufacturing methods. Body 208 and the plurality of contact features 218 can be formed as a single component or separate components and then affixed to each other in various examples.

[0065] FIG. 3 shows measured temperature variation as a function of heater ratios for substrates in a processing chamber with and without an example heat tuner. Here, the heat tuner comprises an aluminum construction with three contact features. Each contact feature of the three contact features is located at a radial location outside of a radius of a substrate contact area. The heater ratios control a power of an outer heating zone to a power of an inner heating zone for a dual-zone heater. The inner heating zone power is controlled to a setpoint (SP), and the outer heating zone power is set based upon the inner heating zone power. In the testbench processing chamber, the dual-zone heater was integrated into a ceramic substrate holder. The temperature variation is measured in a temperature range between a maximum temperature and a minimum temperature. This temperature range is used to indicate uniformity of a corresponding substrate temperature profile.

[0066] The measured temperature variation was obtained using a substrate comprising integrated thermocouples (“thermocouple substrate”). The thermocouple substrate was placed on the ceramic substrate holder without the heat tuner to obtain data for a first temperature variation plot 300. The setpoint of the dual-zone heater was 405°C for a specified temperature at the thermocouple substrate. Next, the heat tuner was placed on the substrate holder, and the thermocouple substrate was placed on the heat tuner to obtain data for a second temperature variation plot 302. For the second temperature variation plot 302, the setpoint was 455°C to enable the specified temperature at the thermocouple substrate. The higher setpoint was used to compensate for a loss of heat due to the gap between the substrate holder and the heat tuner. As canbe seen, the heat tuner provides 33% to 50% more uniformity in the second temperature variation plot 302 compared to the first temperature variation plot 300 (e.g., without the heat tuner).

[0067] In the example of FIG. 2, heat tuner 200 comprises a solid construction in which the body and contact areas are formed from a same material. In other examples, a heat tuner can utilize additional components and / or materials to provide a different heat profile on a substrate compared to that achieved by heat tuner 200. For example, a heat tuner can comprise an optical layer to vary an IR optical property of the heat tuner compared to a heat tuner lacking the optical layer. FIG. 4 schematically shows an example heat tuner 400 comprising an optical layer 402. Heat tuner 400 can be used in any suitable processing chamber, such as processing chamber 202, for example.

[0068] Similar to heat tuner 200, heat tuner 400 comprises a body 404 and a plurality of contact features 406 configured to support body 404 above a substrate holder 408. Body 404 comprises a substrate side 404a and a substrate holder side 404b, and is made from a thermally conductive material. Optical layer 402 is located on substrate holder side 404b. As shown, optical layer 402 is coated directly on body 404. In other examples, one or more intervening layers can be disposed between an optical layer and a body of a heat tuner. Optical layer 402 has one or more optical properties with respect to IR radiation that are different than the thermally conductive material of body 404. The one or more optical properties comprise one or more of absorbance, reflectivity, or transmittance. As one example, optical layer 402 can comprise a multilayer dielectric mirror having a higher IR reflectivity than the thermally conductive material. In this example, less IR radiation would be received at substrate holder side 404b than without optical layer 402. In the depicted example, optical layer 402 covers all of substrate holder side 404b. In other examples, optical layer 402 can cover a portion of substrate holder side 404b. Such a configuration can help to vary the IR radiation received at substrate holder side 404b as a function of location. FIG. 4 is illustrative. An optical layer can have another configuration in other examples.

[0069] Alternatively or additionally, a heat tuner can utilize a non-planar substrate holder side to help control gas gap conduction and / or radiation received at the heat tuner. Such a heat tuner has a varying thickness across the body of the heat tuner, with reference to a distance between a substrate holder side and substrate side of the heat tuner. FIG. 5 schematically depicts such an example heat tuner 500. Heat tuner500 can be used in any suitable processing chamber, such as processing chamber 202. Similar to heat tuner 200, heat tuner 500 comprises a body 502 and a plurality of contact features 504 configured to support body 502 above a substrate holder 506 to form a gap 508. Body 502 comprises a thermally conductive material, a substrate side 502a, and a substrate holder side 502b. However, substrate holder side 502b comprises a non-planar surface configured to vary a distance of gap 508 as a function of location. In the depicted example, the distance of gap 508 is the distance from substrate holder 506 to substrate holder side 502b. Such variation in the distance of gap 508 may change heat received from gas gap conduction and IR radiation as a function of location on substrate holder side 502b.

[0070] In the depicted example, gap 508 has a relatively longer distance in an outer region 514 and a relatively shorter distance in an inner region 516. As such, substrate holder side 502b will receive less heat from a heater of substrate holder 506 in outer region 514 than in inner region 516. In such a manner, the non-planar surface of substrate holder side 502b can help to lower heat transferred in outer region 514. This can help to counter nonuniformities in a heater and / or a substrate holder where temperature gradients are relatively hotter in outer region 514 than inner region 516. As such, the non-planar surface can help heat tuner 500 to provide a more uniform substrate temperature profile at a substrate 518 than a substrate holder without heat tuner 500. In other examples, a substrate holder side can comprise a non-planar surface configured to provide specified first and second heat zones having different temperatures at a substrate. In further examples, a substrate holder side can comprise a non-planar surface having a sloped configuration and / or more than two regions. FIG. 5 is illustrative. In other examples, a substrate holder side can comprise a non-planar surface having another suitable configuration.

[0071] In the above examples, a heat tuner comprises a body having a single material. In other examples, a body can have more than one material. FIG. 6 schematically depicts an example heat tuner 600 utilizing different materials in a body 602. Heat tuner 600 can be used in any suitable processing chamber, such as processing chamber 202, for example. Similar to heat tuner 200, heat tuner 600 comprises a plurality of contact features 604 configured to support body 602 above a substrate holder 606 to form a gap 608. Body 602 comprises a substrate holder side 602a and a substrate side 602b.

[0072] Body 602 also comprises a first thermally conductive material 610 and a second thermally conductive material 620 having different thermal properties. Examples of thermal properties include thermal conductivity and heat capacity. In some examples, first thermally conductive material 610 and second thermally conductive material 620 can also have different optical properties with respect to IR radiation, such as reflectivity or absorptivity, for example. As depicted, first thermally conductive material 610 is located within a first region 622 of a substrate contact area 624. Additionally, a portion of second thermally conductive material 620 is located within a second region 626 of substrate contact area 624. Thus, second thermally conductive material 620 and first thermally conductive material 610 can help to control distribution of the heat received at substrate holder side 602a across corresponding regions of substrate side 602b.

[0073] As a more particular example, first thermally conductive material 610 can comprise aluminum and second thermally conductive material 620 can comprise aluminum oxide. In such an example, the lower thermal conductivity of aluminum oxide can distribute less of the heat received at substrate holder side 602a across second region 626 through conduction in second thermally conductive material 620 than through first thermally conductive material 610. In such a configuration, heat tuner 600 can help to provide a cooler temperature zone in the substrate temperature profile corresponding to second region 626. Correspondingly, first thermally conductive material 610 can help to provide a hotter temperature zone in the substrate temperature profile corresponding to first region 622. In other examples, a body of a heat tuner can comprise more than two thermally conductive materials. In further examples, thermally conductive materials can have another configuration.

[0074] In various examples, a heat tuner can have any suitable combination of structures and / or materials disclosed herein. As one example, a heat tuner can include an optical layer and utilize a non-planar surface to vary a gap. As another example, a heat tuner can include an optical layer and a body with two or more materials. In some such examples, the heat tuner can also utilize a non-planar surface to vary a gap. In further examples, other combinations of configurations are also envisioned.

[0075] FIG. 7 illustrates a flow diagram of an example method 700 for using a heat tuner disposed on a substrate holder in a processing chamber. Method 700 can be implemented using any suitable processing tool, such as processing tool 100, for example. The heat tuner comprises a body with a substrate side, a substrate holder side,and contact features that support the body above a heater of a substrate holder to form a gap between the substrate holder and the body.

[0076] Method 700 comprises, at 702, placing a substrate on the heat tuner in the processing chamber. Method 700 further comprises, at 704, providing power to the heater of the substrate holder to heat the substrate holder. Method 700 additionally comprises, at 706, transferring at least some of the heat from the heater to the substrate holder side of the heat tuner by using one or more of IR radiation or gas gap conduction through the gap to thereby heat the substrate. More particularly, transferring at least some of the heat from the heater to the substrate holder side of the heat tuner using the gas gap conduction comprises transferring the heat using gas in the gap, as indicated at 708. In other examples, 708 may be omitted.

[0077] In some examples, the heat tuner comprises an optical layer on at least a portion of the substrate holder side. The optical layer comprises one or more optical properties with respect to IR radiation that are different than thermally conductive material of the body of the heat tuner, such as different absorbance, reflectivity, and / or transmittance. In such examples, method 700 can comprises, at 710, reflecting some of the IR radiation with an optical layer on at least a portion of the substrate holder side of the heat tuner. In other examples a heat tuner omits such an optical layer.

[0078] Continuing, heating the substrate comprises distributing, at 712, at least some of the heat from the substrate holder side of the heat tuner at least partially across the substrate side by thermally conducting the heat through the body of the heat tuner. Method 700 can optionally comprise replacing the heat tuner, for example, when the heat tuner meets a replacement threshold condition as indicated at 714. Examples of a replacement threshold condition include a specified number of process cycles, visual inspection, film growth outside of process specification, and / or another suitable condition. Further, the heat tuner can be exchanged for another heat tuner having a different temperature profile in some examples.

[0079] The use of a heat tuner as disclosed herein can help to provide a more uniform substrate temperature profile at a substrate arranged on the heat tuner than a substrate temperature profile at a substrate arranged on a substrate holder without the heat tuner. Further, designing, manufacturing, and installing the heat tuner in a processing chamber can be faster and less expensive than designing and manufacturing a new substrate holder to achieve a desired substrate temperature profile.

[0080] It will be understood that the configurations and / or approaches described herein are presented for example, and that these specific examples or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. As such, various acts illustrated and / or described may be performed in the sequence illustrated and / or described, in other sequences, in parallel, or omitted. Likewise, the order of the above-described processes may be changed.

[0081] The subject matter of the present disclosure includes all novel and non- obvious combinations and sub-combinations of the various processes, systems and configurations, and other features, functions, acts, and / or properties disclosed herein, as well as any and all equivalents thereof.

Claims

CLAIMS:

1. A heat tuner for transferring heat to a substrate in a processing tool, the heat tuner comprising: a body comprising a substrate side and a substrate holder side, the substrate side configured to support the substrate, and the substrate holder side configured to receive heat from a heater of a substrate holder; and one or more contact features configured to support the body above the substrate holder to form a gap between the body and the substrate holder, wherein the body comprises a thermally conductive material configured to distribute the heat received at the substrate holder side at least partially across the substrate side.

2. The heat tuner of claim 1, wherein each contact feature of the one or more contact features is located at a radial distance closer to an outer edge of the substrate holder side than a center of the substrate holder side.

3. The heat tuner of claim 2, wherein each contact feature is located at a radial location greater than a radius of a substrate contact area of the substrate side.

4. The heat tuner of claim 1, wherein the substrate holder side comprises a planar surface.

5. The heat tuner of claim 1, wherein the substrate holder side comprises a non- planar surface configured to vary a distance of the gap as a function of location.

6. The heat tuner of claim 1, further comprising an optical layer on at least a portion of the substrate holder side, the optical layer having one or more optical properties with respect to infrared (IR) radiation that are different than the thermally conductive material, the one or more optical properties comprising one or more of absorbance, reflectivity, or transmittance.

7. The heat tuner of claim 1, wherein the thermally conductive material comprises aluminum.

8. A processing tool comprising: a processing chamber; a substrate holder located within the processing chamber, the substrate holder comprising a heater; and a heat tuner comprising a body comprising a substrate side and a substrate holder side, the substrate holder side configured to receive heat from the heater, wherein the body comprises a thermally conductive material configured to distribute the heat received at the substrate holder side at least partially across the substrate side.

9. The processing tool of claim 8, wherein the heat tuner further comprises one or more contact features that supports the body above the substrate holder to form a gap between the body and the substrate holder.

10. The processing tool of claim 9, wherein each contact feature is located at a radial location greater than a radius of a substrate contact area of the substrate side.

11. The processing tool of claim 10, wherein the substrate holder side comprises a non-planar surface configured to vary a distance of the gap as a function of location.

12. The processing tool of claim 8, wherein the substrate holder side comprises a planar surface.

13. The processing tool of claim 8, wherein the heat tuner further comprises an optical layer on at least a portion of the substrate holder side, the optical layer having one or more optical properties with respect to infrared (IR) radiation that are different than the thermally conductive material, the one or more optical properties comprising one or more of absorbance, reflectivity, or transmittance.

14. The processing tool of claim 8, wherein the thermally conductive material comprises aluminum.

15. The processing tool of claim 8, further comprising a gas delivery system configured to control a pressure of the processing chamber in a range of 30 torr to 120 torr.

16. A method for using a heat tuner in a processing chamber of a processing tool, the heat tuner comprising a body with a substrate side, a substrate holder side, and contact features that support the body above a heater of a substrate holder to form a gap between the substrate holder and the body, the method comprising: placing a substrate on the heat tuner in the processing chamber; providing power to the heater of the substrate holder to heat the substrate holder; and transferring at least some of the heat from the heater to the substrate holder side of the heat tuner by using one or more of radiation or gas gap conduction through the gap to thereby heat the substrate.

17. The method of claim 16, wherein heating the substrate comprises distributing at least some of the heat from the substrate holder side of the heat tuner at least partially across the substrate side by thermally conducting the heat through the body of the heat tuner.

18. The method of claim 16, further comprising reflecting some of the radiation with an optical layer on at least a portion of the substrate holder side of the heat tuner.

19. The method of claim 16, wherein transferring the at least some of the heat from the heater to the substrate holder side of the heat tuner using the gas gap conduction comprises transferring the heat using gas in the gap.

20. The method of claim 16, further comprising replacing the heat tuner when the heat tuner meets a replacement threshold condition.

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