Radiation Cooling Substrate Holder

Abstract

A method of cooling a substrate being processed is to process a substrate supported by a substrate holder, wherein the substrate is heated by the processing, and to cool the substrate during processing by radiating heat from the substrate holder, and to maintain the substrate at a steady temperature within tolerance during processing. The substrate is maintained at a steady temperature by heating the substrate holder such that the heat transferred from the substrate by radiating heat from the substrate holder substantially balances the heat transferred to the substrate by processing the substrate and by heating the substrate holder.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Non - Provisional Patent Application No. 17 / 846,867, filed on Jun. 22, 2022, which is hereby incorporated by reference in its entirety.

[0002] The present invention generally relates to substrate processing, and in certain embodiments, to methods, apparatuses, and systems for substrate processing using radiative cooling.

Background Art

[0003] Device formation within a microelectronics workpiece generally requires a series of manufacturing techniques including the formation, patterning, and removal of multiple material layers on a substrate. Since processing the substrate can also involve heating the substrate, cooling the substrate can be important during device formation. High wafer temperatures and temperature non - uniformities can lead to device defects, variations, and failures.

[0004] Some processing techniques process selected portions of the substrate rather than the entire substrate simultaneously. For example, the surface of the substrate can be exposed to a focused beam such that the beam is localized within a spot much smaller than the surface of the substrate and the beam is scanned laterally across the substrate surface. Such local scanning techniques can be even more likely to cause non - uniform heating across the substrate surface.

Summary of the Invention

[0005] According to one embodiment, a method of cooling a substrate during processing is to process a substrate supported by a substrate holder, wherein the substrate is heated by the processing, the processing, and cooling the substrate while processing the substrate by radiating heat from the substrate holder, and maintaining the substrate at a steady temperature within tolerance while processing the substrate. The substrate is maintained at a steady temperature by heating the substrate holder such that the heat transferred from the substrate by radiating heat from the substrate holder substantially balances the heat transferred to the substrate by processing the substrate and by heating the substrate holder.

[0006] According to another embodiment, the substrate holder is a chuck, including a chuck configured to fix the substrate to a first side of the chuck including a first material, a heater disposed on or within the chuck and configured to heat the substrate, and a second material disposed on a second side of the chuck opposite to the first side. The second material includes an exposed surface configured to cool the substrate by emitting heat radiation. The emissivity of the first material is lower than the emissivity of the second material.

[0007] According to yet another embodiment, a substrate processing apparatus includes a vacuum chamber, an electrostatic chuck disposed within the vacuum chamber, a heater integrated with the electrostatic chuck, and a mechanical arm attached to the electrostatic chuck. The electrostatic chuck does not have a liquid cooling mechanism. The electrostatic chuck is configured to clamp the substrate to an upper surface of the electrostatic chuck facing a local processing source. The heater is configured to heat the substrate while processing the substrate. The mechanical arm is configured to move the substrate laterally relative to the local processing source for processing the substrate.

Brief Description of the Drawings

[0008] For a more detailed understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings.

[0009]

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DETAILED DESCRIPTION OF THE INVENTION

[0010] Corresponding numerals and symbols in different drawings generally refer to corresponding parts unless otherwise indicated. The drawings are drawn to clearly show relevant aspects of the embodiments and are not necessarily drawn to scale. The edges of features depicted in the drawings do not necessarily indicate the end of the scope of the features.

[0011] The creation and use of various embodiments are described in detail below. However, it should be understood that the various embodiments described herein are applicable in a variety of specific contexts. The specific embodiments described are merely illustrative of the specific ways of creating and using the various embodiments and should not be construed as limiting to a narrow range.

[0012] Substrate processing often causes heating of the substrate being processed. For example, a plasma process can impart significant thermal energy to a substrate (e.g., a wafer). When left unaddressed, the heating of the substrate can cause various undesirable processing defects and variations due to global and local temperature extremes and non-uniformities. A common type of substrate in the microelectronics industry is a wafer (e.g., a semiconductor wafer). The term "wafer" is used herein under the understanding that, to enhance understanding, various concepts are described, and these concepts are also well applicable to a general category of substrates.

[0013] If the temperature within a region of the wafer deviates from a specific process-dependent temperature range, the process may not be able to produce the desired processing results within that region (and in some cases, may also affect the surrounding regions). Additionally, both process uniformity across the surface of an individual wafer (intra-wafer uniformity) and process uniformity between the wafers being processed (inter-wafer uniformity) are desired.

[0014] Processing techniques that process only a portion of the wafer at a given time, such as scanning techniques, can present even greater challenges than techniques that process the entire surface of the wafer simultaneously because the heating of the wafer is also localized. An example of such a local processing technique is a partial plasma etch process that utilizes a focused plasma beam on the wafer to process the wafer according to a desired pattern (e.g., a raster pattern).

[0015] Partial plasma etching can impart significant thermal energy to the wafer and locally heat the substrate in areas where the wafer is not supported (and thus not cooled) by a substrate holder (e.g., a chuck) that can conduct heat away from the substrate. This can cause temperature non-uniformities both within and between wafers during processing, which can result in etch non-uniformities.

[0016] In many applications, the substrate holder that supports the substrate serves as the primary mechanism for controlling the temperature of the substrate. As a result, the design of the substrate holder can affect the temperature profile of the substrate supported by the substrate holder. Using FIGS. 1, 2A, 2B, and 2C, several effects that the characteristics of a particular substrate holder can have on within-wafer uniformity and between-wafer uniformity are illustrated by way of example. FIGS. 2A, 2B, and 2C show the lateral substrate temperature variations for three types of substrate holders over five consecutively processed substrates, where FIG. 2A shows a partial-diameter substrate holder, FIG. 2B shows a full-diameter substrate holder, and FIG. 2C shows a heated full-diameter substrate holder.

[0017] FIG. 1 shows a support assembly 100 that includes a partial-diameter substrate holder 12 having an overscan shield 15. The partial-diameter substrate holder 12 is configured to support a substrate (e.g., wafer 11). The support assembly 100 can be a particular implementation of the support assembly 100 that can be used in a partial plasma etch process of the wafer 11.

[0018] In this particular example, the partial-diameter substrate holder 12 is an electrostatic chuck (ESC), and the wafer 11 is held in place by an electrostatic force generated by applying a high voltage (positive and negative) to electrodes within the electrostatic chuck. The partial plasma etch process can move the wafer 11 relative to a fixed local plasma source. The electrostatic force (i.e., the clamp force) can be important to prevent the wafer 11 from slipping on the chuck when the chuck is rapidly accelerated and decelerated laterally during scanning under the plasma.

[0019] An overscan shield 15 is provided that extends the horizontal plane created by the wafer 11 beyond the wafer perimeter. When the wafer 11 is scanned under the plasma, the scan can intentionally go beyond the edge of the wafer 11 and ride onto the overscan shield 15 before reversing direction, incrementing in a direction perpendicular to the scan, and scanning across the wafer again in the opposite direction.

[0020] The diameter of the partial-diameter substrate holder 12 is significantly smaller than the diameter of the wafer 11. As a result, in this particular example, the wafer 11 extends beyond the outer periphery from the chuck. When the wafer 11 is processed by scanning under a plasma source, the interaction with the plasma locally imparts thermal energy to the area of the wafer directly beneath the plasma nozzle, heating the wafer surface. In addition, the etching reaction occurring on the wafer surface can also be exothermic, generating additional heat, a portion of which is conducted into the wafer 11.

[0021] In the area where the wafer 11 extends beyond the edge of the partial-diameter substrate holder 12, the thermal energy can be more difficult to dissipate, and the wafer 11 can rapidly increase in temperature. For example, within the area where the chuck supports the wafer, the thermal energy can be more easily dissipated through conduction into the chuck.

[0022] This can result in temperature non-uniformity, as shown in the qualitative graph 201 of FIG. 2A, where the outer periphery of the wafer 11 is much hotter than the central area of the wafer 11 (i.e., the temperature of the wafer surface increases more rapidly with increasing distance from the chuck contact area). The etch rate of the plasma on the wafer surface can be affected by the temperature of the substrate surface (e.g., a strictly monotonically increasing function of the surface temperature). Therefore, in the case of the illustrated temperature profile, the outer periphery can etch faster than the cooler central area, unnecessarily. This can result in unacceptably high in-wafer non-uniformity of the etch.

[0023] When the processing chamber in which the partial plasma etching is performed is not used for some time, the wafer chuck can cool slowly to the ambient temperature. This cooling can occur through slow heat conduction through the mechanical arm supporting the chuck or through slow thermal radiation to the cooler ambient chamber walls.

[0024] As shown in FIG. 2A, when the first wafer W1 is processed, the chuck surface is relatively cold. Heat from the wafer readily conducts into it, locally cooling the wafer within the contact area. The heat conducted into the chuck warms the chuck itself, such that when the second wafer W2 is processed, it is placed on the chuck at a temperature substantially warmer than the first wafer W1. That is, the chuck absorbs heat energy faster than it dissipates it, so the chuck temperature increases between wafers. Therefore, heat conducts from the chuck into the wafer before and during processing.

[0025] The third wafer W3, similarly, experiences a higher temperature, and a similar effect can be experienced for the fourth wafer W4 and the fifth wafer W5, with it becoming somewhat smaller with the increase in the initial chuck temperature. Since the chuck is at a higher temperature, the thermal energy generated from the plasma conducts less readily into the chuck, such that as the wafers are processed one after another, the chuck temperature gradually rises until it reaches a quasi-steady state or the processing is paused and it begins to cool down gradually again. This variability in chuck temperature can cause unacceptably high non-uniformity between wafers in the etch.

[0026] One potential disadvantage of a lower wafer temperature is the adsorption of compounds on the wafer surface that may exist later during processing. For example, the wafer may leave the processing chamber with sulfur compounds adsorbed on the wafer surface after a partial plasma etch process. These compounds can become undesirable for various reasons, including toxicity. In the case of sulfur, the adsorbed compounds can cause an offensive odor that can be detected after the wafer is removed from the processing chamber, such as when the wafer is in a front opening unified pod (FOUP).

[0027] Next, referring to FIG. 2B, the qualitative graph 202 illustrates the difference in the in-wafer temperature profile when the full-diameter substrate holder 13 is used. The full-diameter substrate holder 13 has a diameter at least as large as the wafer 11 and, as shown, may be the same size. The temperature curve of graph 202 indicates that this configuration may have significantly improved in-wafer temperature uniformity over the partial-diameter substrate holder 12 of FIG. 2A due to the continuous contact of all parts of the wafer 11 with the full-diameter substrate holder 13. Additionally, the thermal mass of the full-diameter substrate holder 13 is higher and, advantageously, results in a reduction in the temperature rise between wafers.

[0028] While the full-diameter substrate holder 13 improves in-wafer temperature uniformity, it may still be vulnerable to asymmetries in other parts of the support assembly. For example, the lower temperature of the wafer on the left side of graph 202 may be the result of a mechanical arm attached to the full-diameter substrate holder 13 and extending leftward from the central region of the full-diameter substrate holder 13. Heat can be transferred through the mechanical arm, resulting in a lower temperature where the arm is closer. The lower temperature can also increase undesirable adsorption compounds such as sulfur compared to the partial-diameter substrate holder 12, which results in a higher average wafer temperature.

[0029] Temperature variations across the wafer from one side to the other can also occur due to a rastering process that starts on one side of the wafer and ends on the other. Since some heat conducts laterally through the substrate holder during processing, the side of the wafer that is processed last may experience a somewhat higher temperature than the side that was processed first.

[0030] Note that increasing the time between wafers being processed may also be used to reduce or eliminate non-uniformity between wafers. However, this is typically unrealistic due to the long time scales required to allow the processing heat to fully dissipate from the substrate holder. Such a loss of throughput would be an unacceptable solution in many applications.

[0031] In qualitative graph 203 of FIG. 2C showing the heated full-diameter substrate holder 14 including heater 16, one method of reducing within-wafer non-uniformity is illustrated. In contrast, the substrate holders of FIGS. 2A and 2B are not heated. Heater 16 can raise the wafer 11 to a quasi-steady state by transferring additional thermal energy into the wafer 11, without relying on heat being slowly added over the course of wafer processing iterations.

[0032] Advantageously, the first wafer W1 has a substantially same temperature profile as the fifth wafer W5 and the like. Additionally, since the heated full-diameter substrate holder 14 can be rapidly heated to a quasi-steady state before processing the first wafer, the within-wafer uniformity is also improved.

[0033] However, the specific value of the quasi-steady state temperature for a given implementation depends on the ability of the support assembly to passively or actively cool the supported wafer. If the cooling is insufficient, the value will be higher than the upper boundary of the allowable temperature range for a given process. Some, or even most, of the wafer cooling options may be rendered unavailable due to implementation considerations, process details, cost, complexity, and other design considerations.

[0034] One common technique for cooling a wafer on a wafer chuck (i.e., substrate support) is to circulate a liquid within the chuck to transport and dissipate heat from the wafer. The liquid cooling mechanism conducts thermal energy from the wafer to the liquid circulated within a closed system. The liquid is then transferred from the chuck to dissipate heat elsewhere via forced liquid convection.

[0035] However, liquid cooling requires the inclusion of complex and leak-prone piping within the chuck. One particular application where liquid cooling can be especially unrealistic is for processes using non-fixed wafer chucks such as scanning techniques like the partial plasma etch process referenced above. To scan the surface of the wafer, the chuck can move laterally at very high speeds and with large accelerations and decelerations, and / or rotate.

[0036] Liquid cooling solutions in such systems adapted for lateral wafer movement would require flexible piping within a mechanical arm that has the ability to reliably withstand extreme movement. For compatibility with a rotating substrate, indirect contact (e.g., using gas contact such as He) would need to be used to provide heat conduction between the rotating and fixed parts of the wafer chuck. Enclosing gas within the wafer chuck (e.g., an ESC) creates greater complexity and an additional potential for leakage. Also, as is evident from recent global shortages, helium can be expensive.

[0037] Convective cooling using a background gas is another technique that can be used to cool the wafer during processing. However, this also cannot be an option because the background gas increases the pressure within the processing chamber, which can negatively impact process performance (e.g., etch spot size, shape, or etch rate) and can create additional chemical effects that can affect the process.

[0038] Another form of wafer cooling that uses a third heat transfer method is radiative cooling. In contrast to liquid cooling, which uses a combination of heat conduction and heat advection, radiative cooling relies on the surface radiating heat into the surrounding environment. The ability of the support assembly to dissipate heat through radiative heat transfer depends on the surface area, temperature, and emissivity of the exposed surface (and the influence of the surrounding environment, e.g., the chamber. This will be assumed to be negligibly small for the following first-order calculations but could be a design consideration for a particular implementation of the processing environment).

[0039] For example, a simplified form of the radiation transfer equation for radiative heat flux can be written as q = εσT 4 where q is the radiative heat flux in W / m 2 units, ε is the emissivity of the surface of the object, σ is the Stefan-Boltzmann constant, and T is the absolute temperature of the object. Therefore, the total thermal energy in watts radiated by the object is Q = qA, where A is the total surface area of the object.

[0040] These equations demonstrate that the ability of the substrate holder (e.g., chuck) to transfer heat via radiation can be increased by increasing the temperature, surface emissivity, and surface area of the substrate holder. In particular, the total radiative heat energy is proportional to T 4 and allows for a large increase in Q in response to a much smaller increase in T. This characteristic of radiative heat transfer can be advantageously utilized to cool the substrate during processing.

[0041] (e.g., as qualitatively shown above for the partial diameter substrate holder 12 in FIG. 2A) The temperature rise near the unsupported wafer edge indicates that for a partial plasma etch process, the thermal process energy absorbed by the wafer per second (in this case, imparted to the wafer by a focused plasma beam) is on the order of tens of watts (e.g., about 10 W to about 100 W) and can be considered 63 W for the purposes of this example.

[0042] The above equation can be used to estimate the amount of heat that the substrate holder can dissipate via radiative cooling. For conceptual purposes, the surface area of the substrate holder can be assumed to be about 0.15 m 2 (corresponding to a 300 mm diameter chuck that is 10 mm thick and not considering the effect of the wafer itself which can increase or decrease actual cooling). A typical material for the wafer chuck is polished aluminum which has an emissivity in the range of about 0.039 to about 0.057.

[0043] At 473 K (about 200 °C), taking ε = 0.057 and σ to be approximately 5.67×10 -8 W / m 2 / K 4 If it is recognized that this is the case, a simple calculation using the above equation shows that the thermal energy radiated per second by the substrate holder is approximately 24 W, which indicates that radiative heat transfer can be a significant fraction of the heat dissipated at 200 °C, but without other cooling mechanisms, it would be insufficient to prevent further heating of the substrate.

[0044] In comparison, hard anodized aluminum has a much higher emissivity of 0.9. The same calculation assuming a hard anodized surface with ε = 0.9 results in radiative heat of approximately 380 W at 200 °C, much higher than that of polished aluminum and an order of magnitude higher than the heat transferred to the wafer through the process. Increasing the substrate temperature to about 350 °C results in dissipated heat of over 1000 W. In various embodiments, the substrate holder can be configured to provide sufficient radiative heat dissipation to operate the substrate holder at a temperature lower than 350 °C. However, considering the above calculations, it may be advantageously practicable to operate a substrate holder with a moderate to high emissivity at a relatively low temperature (200 °C or less) while providing sufficient radiative heat dissipation to achieve a good balance and good temperature control.

[0045] Accordingly, the inventors have discovered that a substantially steady substrate temperature can be achieved by heating the substrate holder to a temperature high enough to cause higher radiative heat dissipation than the absorption of thermal energy from a processing source (e.g., plasma) (e.g., using a heater integrated within a wafer chuck in thermal contact with the wafer). When the processing source begins to transfer heat to the substrate (e.g., the processing source is activated and impinges on the surface of the wafer), the temperature control system can reduce the heating (e.g., by reducing the current to the heater) such that the heat transfer to and from the support assembly is balanced and the temperature is maintained (i.e., a steady temperature).

[0046] By adjusting various design parameters such as the surface area and emissivity of the surface material, the steady-state temperature can advantageously be within the allowable temperature range for the selected process. This cooling method can also advantageously improve the in-wafer temperature uniformity and the inter-wafer temperature uniformity. A further advantage of this flexibility can be to allow the omission of other cooling mechanisms from the support assembly, whether by preference or because other cooling methods are unrealistic for a given application.

[0047] For example, the solution described herein may be suitable for applications where it may be difficult or impossible to achieve a controlled and uniform wafer temperature using other cooling methods, such as liquid cooling technology or gas cooling technology. One such application can be a raster process (i.e., a process that utilizes a scanning pattern to expose portions of a substrate as opposed to exposing large areas of the substrate at once). The raster process can move the substrate relative to a fixed exposure area (e.g., a fixed local plasma source) (e.g., using a mechanical arm), which can make the implementation of liquid cooling difficult.

[0048] In addition, since the substrate is heated during processing, the rate of many processes (e.g., etching) increases with temperature, so the radiative cooling method can have the further advantage of increasing throughput. This can also have the concomitant advantage of preventing the gas emission of adsorbed compounds from the substrate, such as sulfur vapor gas emission, and reducing or eliminating the need for post-treatment heat treatments that are sometimes used.

[0049] The embodiments provided herein describe various methods, apparatuses, and systems for substrate processing, and in particular, methods, apparatuses, and systems using radiative cooling. An exemplary method for cooling a substrate during processing is described with reference to FIG. 3. An exemplary support assembly utilizing radiative cooling is described with reference to FIG. 4. Five additional exemplary support assemblies are described with reference to FIGS. 5-9, while an exemplary support assembly including a mechanical arm is described with reference to FIGS. 10A and 10B. Next, an exemplary processing system is described with reference to FIG. 11, and another processing system using a local processing source is described with reference to FIG. 12.

[0050] FIG. 3 shows a method for cooling a substrate during processing by heating the substrate, according to an embodiment of the present invention. The method of FIG. 3 may be performed using the systems and apparatuses described herein in combination with other methods. The configuration and numbering of each step in FIG. 3 are illustrated in a logical order but are not intended to be limiting. The method steps of FIG. 3 may be performed in any suitable order or concurrently with each other, as would be apparent to one of ordinary skill in the art.

[0051] Referring to FIG. 3, a method 300 for cooling a substrate during processing includes a step 301 of processing a substrate supported by a substrate holder. The substrate is heated by the processing. For example, the process may be an etching process, and in some embodiments, a plasma process. The process may be a global process that processes all desired regions of the substrate simultaneously, or a local process that processes only a portion of the substrate at any given time (e.g., a scanning process using a focused beam such as a plasma beam, an ion beam, an electron beam, a laser beam, and the like).

[0052] Simultaneously with processing the substrate in step 301, the substrate is cooled by radiating heat from the substrate holder in step 302. Also, during the processing of the substrate in step 301, in step 303, first, heat is conducted into the first substrate holder, then through the holder to the surface of the holder, and then the heat transferred from the substrate by radiating heat from the substrate holder is substantially balanced with the heat transferred to the substrate by processing the substrate and heating the substrate holder by heating the substrate holder so as to maintain the steady temperature of the substrate.

[0053] Since steps 301, 302, and 303 are all performed simultaneously while the substrate is being processed, these steps can be considered as processing stage 304 of method 300. During processing stage 304, in order to cool the substrate and maintain the steady temperature, the substrate holder is intentionally heated to a temperature higher than the temperature that could otherwise be achieved during processing.

[0054] Optionally, before processing the substrate (i.e., while the substrate is supported by the substrate holder, but before step 301 of processing the substrate), in step 305, the substrate can be maintained at a steady temperature by heating the substrate holder such that the heat transferred from the substrate through the heat radiation of the substrate holder is substantially balanced with the heat transferred to the substrate by heating the substrate holder.

[0055] Since there is no heat added to the substrate through the process, step 305 may require transferring more heat to the substrate than during step 303 to maintain the steady temperature. For example, before processing the substrate, during step 305, the substrate holder can be heated to transfer heat energy at a first rate to maintain the substrate at a steady temperature, and during the processing of the substrate, in step 303, the heating of the substrate holder can be reduced to transfer heat energy at a second rate, which is less than the first rate, to compensate for the heat transferred to the substrate by processing the substrate.

[0056] Therefore, even when the heater is stopped, it may be useful to first operate the substrate holder at a temperature higher than the heat addition from the thermal energy of the substrate processing (e.g., plasma etching) so that the substrate holder temperature does not continue to rise. Also, it may be useful to operate at an even higher temperature so that the heat dissipation when the heater is stopped is of the same magnitude as the heat addition when the heater is operating.

[0057] After processing step 304, in step 306, the substrate can be removed from the substrate holder. Depending on the value of the steady-state temperature and the post-process requirements for the substrate, an additional optional step of cooling the substrate may be utilized after processing the substrate and removing it from the substrate holder.

[0058] An optional step 307 of maintaining the substrate holder at a steady-state temperature by heating the substrate holder can be performed after removing the substrate. For example, step 307 can be incorporated when the process is to be repeated for subsequent wafers (shown as step 308). Subsequent substrates can be placed within the system or otherwise provided such that they are supported by the substrate holder (step 309). Next, steps 301, 302, and 303 can be performed on subsequent and future substrates as desired. Since the steady-state temperature is maintained at all times before, during, and after processing, wafer-to-wafer temperature uniformity is advantageously maintained.

[0059] When the substrate is first introduced into the system (e.g., when placed on the substrate holder), the substrate does not have to be at the same temperature as the substrate holder (e.g., it can be at a temperature lower than the steady-state temperature or even warmer). In this case, bringing the substrate to the steady-state temperature also includes heating the substrate using a heater or cooling the substrate through radiative cooling of the substrate holder.

[0060] The steady temperature can be maintained within tolerances. The tolerances can include various measurements of uniformity, such as temperature variations within the wafer, process temperature variations (the amount by which the average temperature of the substrate changes during processing), temperature variations between wafers, and others. In some embodiments, the tolerance for temperature variations within the wafer is less than about 4 °C, and in one embodiment, less than about 2 °C. In one embodiment, the tolerance for process temperature variations is less than about 1 °C. The tolerance for temperature variations between wafers can be less than about 2 °C, and in one embodiment, less than about 1 °C.

[0061] Various features can be employed and can facilitate the implementation of a radiative cooling method using a substrate holder. In one embodiment, the substrate holder is in complete contact with the supported substrate (e.g., the back surface of the substrate) from the center to the edge. As described above with reference to FIG. 2B, this can advantageously improve the temperature uniformity within the wafer.

[0062] As described above, even a substrate holder with a low emissivity can achieve significant radiative cooling. However, incorporating a material with a higher emissivity on the surface of the substrate holder can advantageously improve the efficiency of radiative cooling and can sometimes be necessary to bring the steady temperature within the desired range suitable for a given type of process. For example, so-called high emissivity (HE) materials can be used, but medium emissivity materials can also offer advantages over the bare machined or polished metal surfaces conventionally used in processing systems.

[0063] In some embodiments, the substrate is heated using an electrical heater, and in one embodiment, a resistive heater is used. The heater can be integrated within or disposed on the substrate holder. In one embodiment, the heater is a flexible resistive heater. In other embodiments, the heater is another type of resistive heater, such as a cartridge heater or a ceramic heater. The resistive heating element can be directly embedded within the ceramic holder material by forming ceramic around it. Additionally, or alternatively, the heater can be an external heat source, such as a radiant heat source.

[0064] In some embodiments, the substrate can be monitored by measuring its temperature during processing. At this time, the heating of the substrate holder can be dynamically adjusted according to the change in the measured temperature detected during monitoring the measured temperature. This can advantageously enable the steady temperature to be continuously maintained even when the conditions during processing vary. The substrate (e.g., a silicon wafer) can also have a variable emissivity depending on factors such as thin films and devices on and embedded in its surface. The dynamic adjustment of the heat supplied by the heater can also advantageously compensate for these changes in the heat dissipation of the substrate itself.

[0065] Achieving temperature control requires the ability to add heat to increase the temperature and the ability to dissipate heat when the temperature is too high. Therefore, the control of the temperature (i.e., the steady temperature) is achieved when the heat addition and heat dissipation mechanisms are relatively balanced. In this case, the heat dissipation can mainly be through radiative heat transfer from the outward-facing surface of the support assembly (e.g., dissipation onto the walls of the processing chamber through the surrounding vacuum).

[0066] To achieve this purpose, the steady temperature can be controlled using a feedback control system coupled to a heater (e.g., using a temperature monitoring device) to maintain the chuck, and thus the wafer sitting on it, at a constant temperature. For example, one or more resistance temperature detectors (RTDs), or other temperature monitoring devices such as thermocouples or thermistors, can be used to monitor the temperature at various points on the substrate holder and heater, and anywhere else within the processing system that may be useful for maintaining the steady temperature. In some implementations, separate heaters for different regions of the wafer can also be utilized, which can advantageously extend the fine control of the temperature uniformity within the wafer.

[0067] In various embodiments, the heat transferred to the substrate by the heater and the heat transferred to the substrate by processing the substrate are primarily dissipated (e.g., balanced thereby) by radiative heat transfer to the surrounding chamber. For example, substrate processing can be performed under vacuum (e.g., under high vacuum, ultra-high vacuum, although other higher or lower vacuum regions are also possible), removing the convective heat path into the processing chamber.

[0068] In addition, as described above, the contribution of cooling from other mechanisms of heat transfer, such as liquid cooling of the substrate holder, heat conduction through the substrate holder, and cooling of the substrate through the background gas, may be absent or minimal. In some embodiments, during substrate processing, heat is not transferred from the substrate using a liquid. In one embodiment, during substrate processing, heat is not substantially transferred from the substrate via convection. That is, the substrate is not cooled using a fluid (liquid or gas phase), and any incidental cooling by the process gas or the like is negligible compared to radiative cooling from the substrate holder (e.g., less than 10% of the total cooling).

[0069] The radiative cooling method described herein can be advantageous for both fixed support assemblies and non-fixed holding assemblies for various reasons. However, a fixed support assembly (e.g., a chuck used for processing that is fixedly seated within the processing chamber) can be more easily cooled using a fluid (e.g., water, gas, heat transfer fluid) or by heat conduction to the outside of the processing chamber (in which case it is more easily dissipated to the environment).

[0070] In various embodiments, substrate processing can be a local processing technique such as a scanning (e.g., raster) technique. In one embodiment, processing the substrate includes moving the substrate laterally relative to a fixed local processing source. For example, the lateral movement can be achieved using an arm attached to the substrate holder. While the substrate is being moved (quite rapidly in some cases), the substrate is both heated and cooled to maintain the substrate at a constant temperature.

[0071] Figure 4 shows an exemplary support assembly including a substrate holder and a heating element configured to radiatively cool a substrate, according to an embodiment of the present invention. The support assembly of FIG. 4 can be used to perform any of the methods described herein, such as the method of FIG. 3 for example.

[0072] Referring to FIG. 4, support assembly 400 includes a substrate 10 (e.g., a wafer) supported (e.g., immobilized) by a substrate holder 420. In various embodiments, substrate holder 420 is a chuck. In one embodiment, substrate holder 420 is an ESC. Substrate holder 420 is configured to effect heat conduction from the contact surface of substrate 10 with substrate holder 420 to an exposed surface (e.g., a back surface, a high emissivity surface of substrate holder 420 such as a back surface) of substrate holder 420 to radiate and lose excess heat acquired by substrate 10 by processing substrate 10.

[0073] Substrate holder 420 includes a heater 430 that can be disposed within or on substrate holder 420. Heater 430 is configured to transfer heat to substrate holder 420 (conceptually shown by a positive change in temperature +ΔT H Note, however, that heat transfer is more specifically the transfer of thermal energy Q that results in an increase in temperature that depends on properties of the material that absorbs thermal energy such as specific heat capacity). Substrate 10 is in thermal contact with substrate holder 420, thereby facilitating further transfer of heat supplied to substrate 10 by heater 430.

[0074] An emissive material 422 (e.g., including a metal such as aluminum, a ceramic material, or other materials) is included within substrate holder 420. As described above, emissive material 422 can have any emissivity ε, and its exact value can depend on design considerations for a given application. For example, substrate holder 420 during processing (+ΔT P ), and heat transferred to substrate 10 by heater 430 is radiatively cooled (-ΔT R) is configured to cool the substrate 10 so as to balance the heat transferred from and lost to the substrate 10. This is shown in FIG. 4 (and elsewhere) using arrows directed toward the substrate 10 and arrows directed away from the substrate 10. Thus, the substrate 10 can be maintained at a steady temperature during processing.

[0075] There are no specific requirements regarding the emissivity ε of the radiation material 422, but it may be advantageous for the substrate holder 420 to be formed of or include a material having a higher emissivity than bare machined or polished metals and / or light-colored surfaces that may conventionally be employed. For example, the radiation material 422 may, in some embodiments, have a rough surface. In some embodiments, the radiation material 422 is a dark-colored material such as silicon carbide or hard anodized aluminum (which may have a dark slate gray surface). For example, a black or dark-colored surface can have more than 10 times the radiative heat dissipation of a shiny silver surface.

[0076] The substrate holder 420 is shown as including the radiation material 422 throughout, but the radiation material 422 can also be implemented as a coating on all or part of the surface of the substrate holder 420. More than one type of radiation material may be included, and the substrate holder 420 can even include an emissivity gradient to further adjust the temperature profile of the substrate 10. The radiation material 422 can also be implemented as a material separate from the primary material of the substrate holder 420 and suitably attached to the substrate holder 420.

[0077] In various embodiments, only the heat generated by the processing of the substrate 10, the heat generated by the heater 430, and the radiative cooling by the substrate holder 420 are significant sources of heat transfer to and from the substrate 10. However, in other embodiments, there may be additional forms of heating and cooling. The heater 430 can further be used to appropriately balance the total heat transfer to and from the substrate 10 during processing.

[0078] The substrate holder 420 can be of any desired size and shape, and the details thereof can depend on the substrate 10 being processed. In some embodiments, the substrate holder 420 is circular. The major dimension of the substrate holder 420 (e.g., substrate holder diameter 17) can be of any size relative to the major dimension of the substrate 10 (e.g., substrate diameter 18). In some embodiments, the substrate holder diameter 17 is selected such that it is at least as large as the substrate diameter 18. That is, the side of the substrate holder 420 (e.g., chuck) facing the substrate 10 fully overlaps the back surface of the substrate 10 (which is the major surface of the substrate 10). As described above, this can provide an additional advantage in wafer temperature uniformity.

[0079] Of course, the substrate holder diameter 17 can also be larger than the substrate diameter 18. In one embodiment, the substrate holder diameter 17 is approximately equal to the substrate diameter 18. The substrate holder diameter 17 can also be slightly smaller than the substrate diameter 18 while achieving the same or similar advantages, and the beneficial effect of having substrates and substrate holders of similar sizes gradually decreases as the substrate holder diameter 17 is decreased relative to the substrate diameter 18. This can advantageously prevent wafer temperature non-uniformity that can occur due to additional cooling of the substrate holder 420 extending beyond the extent of the substrate 10.

[0080] FIG. 5 shows an exemplary support assembly according to an embodiment of the present invention that includes a substrate holder that supports a substrate and includes a material having a higher emissivity than the emissivity of the material facing the substrate. The support assembly of FIG. 5 can be a particular implementation of other support assemblies described herein, such as, for example, the support assembly of FIG. 4. Similarly labeled elements may be as described above.

[0081] Referring to FIG. 5, the support assembly 500 includes a substrate 10 supported by a substrate holder 520. Here and hereinafter, for the sake of brevity and clarity, it should be noted that elements according to the pattern [x10] adopt rules that can be related implementation forms of the substrate holder in various embodiments. For example, the substrate holder 520 may be the same as the substrate holder 420 unless otherwise specified. Similar (but not necessarily identical) rules are also adopted for other elements as revealed by the use of similar terms in combination with the above-mentioned numbering system.

[0082] The support assembly 500 may be similar to the support assembly 400 of FIG. 4, except for the difference between the emissivity of the material on the exposed surface of the substrate holder 520 and the emissivity of the material of the substrate holder 520. That is, the substrate holder 520 includes a radiation material 522 having an emissivity ε, which has a higher emissivity than other materials of the substrate holder 520. For example, the material of the substrate holder 520 on the upper side facing the substrate 10 may have a lower emissivity than the emissivity ε of the radiation material 522 on the exposed lower side of the substrate holder 520.

[0083] This can be advantageous for various reasons. For example, the temperature profile of the substrate 10 can be advantageously adjusted by the radiation characteristics of the surface of the substrate holder 520. The materials of the substrate holder 520 other than the radiation material 522 can also be selected for reasons other than emissivity. Including the radiation material 522 having a higher emissivity can advantageously enable the selection of other materials of the substrate holder 520 without prioritizing their radiation characteristics.

[0084] The radioactive material 522 can be a separate material attached to the substrate holder 520. In some cases, the radioactive material 522 can be a coating or film that is sprayed, applied, or otherwise applied to an existing surface of the substrate holder 520. In various embodiments, the radioactive material 522 is formed by treating an existing surface of the substrate holder 520. In one embodiment, the radioactive material 522 is formed by hard anodizing the material of the substrate holder 520. For example, the substrate holder 520 can be formed from aluminum (e.g., including a polished aluminum surface), and the radioactive material 522 can be hard anodized aluminum.

[0085] Other surface coatings, such as Nedox® coatings by General Magnaplate, can have a very dark to black surface with high emissivity. These (and other coatings) can provide additional advantages in addition to emissivity characteristics such as improved resistance to corrosion by various chemical species.

[0086] An optional overscan shield 540 for extending the surface of the substrate 10 can be included. For example, the overscan shield 540 can be attached to the outer periphery of the substrate holder 520. Alternatively, the overscan shield 540 can be integrated with the substrate holder 520 or extend partially or completely under the substrate holder 520. The overscan shield 540 is different from the overscan shield 15 shown in FIG. 1 in that it does not overlap the lower surface of the substrate holder 520 that is vertically aligned with the substrate 10.

[0087] The overscan shield 540 can also provide the advantage of increasing heat dissipation by increasing the surface area available for radiative heat transfer. However, depending on the implementation, it may preferentially dissipate heat from around the outer periphery of the chuck and thus, by cooling the outer periphery more than the center, may worsen the temperature non-uniformity within the wafer. Therefore, it may be advantageous to provide a thermal insulation material or gap between the overscan shield 540 and the rest of the substrate holder, select a non-conductive material for the overscan shield itself, or mount the chuck assembly in a manner such that heat is not preferentially removed from the chuck outer periphery. For example, a thermal insulation material may be included to reduce the effect of the lateral heat conduction path at the edge of the substrate 10.

[0088] FIG. 6 shows an exemplary support assembly according to an embodiment of the present invention, including a substrate holder and a heating element disposed between the substrate holder and the bottom cover. The support assembly of FIG. 6 can be a particular implementation of other support assemblies described herein, such as, for example, the support assembly of FIG. 4. Similarly labeled elements may be as described above.

[0089] Referring to FIG. 6, the support assembly 600 includes a substrate 10 supported by a substrate holder 620. The support assembly 600 can be similar to the support assembly 500 of FIG. 5, except that it includes a radiation material 622 or a plate 625 formed from the radiation material 622. The plate 625 is attached to the substrate holder 620. For example, the plate 625 can be attached to the lower surface of the substrate holder 620. This can have the advantage of promoting temperature uniformity and conducting heat to the surface of the support assembly 600 for radiation of that heat to the surrounding wall of the processing chamber through the vacuum.

[0090] As shown, a heater 630 can be disposed between a substrate holder 620 and a plate 625. The plate 625 can be used to clamp the heater 630 in place. Additionally, the plate 625 can assist in lateral heat dissipation. In one embodiment, the heater 630 can be a flexible resistive heater made by sandwiching an electrical conductor trace between two insulating layers, such as polyimide. However, other types of resistive electrical heaters, such as cartridge heaters or ceramic heaters, can also be used.

[0091] FIG. 7 shows an exemplary support assembly according to an embodiment of the present invention, including a substrate holder and an overscan shield that at least partially lies beneath the full-diameter substrate holder. The support assembly of FIG. 7 can be a particular implementation of other support assemblies described herein, such as the support assembly of FIG. 4. Similarly labeled elements may be as described above.

[0092] Referring to FIG. 7, the support assembly 700 includes a substrate 10 supported by a substrate holder 720 that includes a heater 730. The support assembly 700 can be similar to the support assembly 600 of FIG. 6, except that it includes an overscan shield 740 that extends partially covering the lower surface of a plate 725 attached to the substrate holder 720. The overlap can be included, for example, as a way to attach the overscan shield 740 to the substrate holder 720. The extension advantageously does not have to overlap the plate 725 at all points along the edge of the plate 725. Instead, a relatively thin extension may overlap the plate 725 to avoid substantially interfering with the radiative cooling effect of the radiative material 722 at the edge of the plate 725.

[0093] FIG. 8 shows an exemplary support assembly according to an embodiment of the present invention, including a substrate holder having an integrated overscan shield. The support assembly of FIG. 8 can be a particular implementation of other support assemblies described herein, such as the support assembly of FIG. 4. Similarly labeled elements may be as described above.

[0094] Referring to FIG. 8, the support assembly 800 includes a substrate 10 supported by a substrate holder 820 that includes a heater 830. The support assembly 800 may be similar to the support assembly 500 of FIG. 5, except that an overscan shield 840 integrated with the substrate holder 820 may be included. In this particular example, a radiation material 822 may be included on some or all of the lower surface of the substrate holder 820 (including the lower surface of the overscan shield 840).

[0095] FIG. 9 shows another exemplary support assembly including a substrate holder having an integrated overscan shield according to an embodiment of the present invention. The support assembly of FIG. 9 may be a particular implementation of other support assemblies described herein, such as, for example, the support assembly of FIG. 4. Similarly labeled elements may be as described above.

[0096] Referring to FIG. 9, the support assembly 900 includes a substrate 10 supported by a substrate holder 920 that includes a heater 930. The support assembly 900 may be similar to the support assembly 800 of FIG. 8, except that a radiation material 922 is also included on the upper surface of an overscan shield 940 integrated with the substrate holder 920. That is, the overscan shield 940 may include an exposed upper surface that extends laterally from the outer edge of the substrate 10 that includes the same radiation material 922 included on the lower surfaces of the overscan shield 940 and the substrate holder 920.

[0097] FIGS. 10A and 10B show an exemplary support assembly including a substrate holder attached to a mechanical arm configured to move a substrate laterally relative to a processing source during processing, where FIG. 10A is a side view of the support assembly and FIG. 10B shows a bottom view of the support assembly. The support assemblies of FIGS. 10A and 10B may be particular implementations of other support assemblies described herein, such as, for example, the support assembly of FIG. 4. Similarly labeled elements may be as described above.

[0098] Referring to FIGS. 10A and 10B, the support assembly 1000 includes a substrate 10 supported by a substrate holder 1020 that includes a heater 1030. In one embodiment (as shown), the substrate holder 1020 is an ESC that receives a clamp voltage V ESC to hold the substrate 10 fixed on the substrate holder 1020. The ESC can advantageously prevent the substrate 10 from moving even during rapid acceleration and deceleration (e.g., 5 g of lateral acceleration without detectable slippage).

[0099] An overscan shield 1040 is attached to the substrate holder 1020. A radiation material 1022 is included at least within a plate 1025 attached to the substrate holder 1020. A mechanical arm 42 is attached to the substrate holder 1020. The mechanical arm 42 is configured to move the substrate 10 during processing. For example, the mechanical arm 42 can be configured to cause a lateral movement 47 of the substrate 10 relative to a fixed local processing source. Additionally or alternatively, the mechanical arm 42 can be configured to cause a rotational movement 45, for example, using a rotary drive 44.

[0100] Since the motors, gearboxes, drives, and control electronics of the mechanical arm 42 can be present in implementations that do not have radiating cooling capabilities, the mass of the support assembly 1000, including the substrate holder 1020, heater 1030, plate 1025, and overscan shield 1040, can be advantageously minimized while still providing the desired radiating cooling capabilities to avoid their complex and costly modifications.

[0101] The substrate holder 1020 may also include one or more lift pin holes 24 that penetrate the substrate holder 1020 (and potentially, as shown, penetrate the heater 1030 and / or the plate 1025). The lift pin holes 24 are configured to allow the passage of substrate lift pins that are actuated to lift the substrate 10 from the surface of the substrate holder 1020 so that the substrate 10 can be picked up by a transfer robot end effector accessing the back side of the substrate 10 for handling. Similarly, the lift pins can be actuated downward to lower the next substrate 10 onto the surface of the substrate holder 1020.

[0102] FIG. 11 shows a substrate processing apparatus including a substrate holder configured to radiatively cool a substrate while the substrate is being processed by heating the substrate holder during processing, according to an embodiment of the present invention. The substrate processing apparatus can be used to perform any of the methods described herein, such as, for example, the method of FIG. 3. Similarly labeled elements may be as described above.

[0103] Referring to FIG. 11, the substrate processing apparatus 1100 includes a support assembly disposed within a processing chamber 50 and including a substrate holder 420, which can be as described above. The processing chamber 50 is the processing chamber 50 in various embodiments. When the substrate holder 420 operates in a vacuum, the heat added by the heater 430 and the heat conducted from the substrate 10 to the substrate holder 420 from the processing source 1152 can be advantageously dissipated from the substrate holder 420 primarily through radiative heat transfer to the surrounding walls of the processing chamber 50.

[0104] In an implementation where the ESC is utilized as the substrate holder 420, an ESC controller 54 may be included to control the clamping of the substrate 10 (e.g., a wafer) to the surface of the ESC.

[0105] A heater controller 56 for maintaining the substrate 10 at a constant temperature is included within the substrate processing apparatus 1100. The heater controller 56 can be configured to control the application of power to the heater 430, such as 1 - phase 208VAC power.

[0106] The substrate temperature detector 57 may be included near or in contact with the substrate 10. The substrate temperature detector 57 may be configured to monitor the temperature in the substrate 10. In the heater 430, a heater temperature detector 58 may be included. The heater temperature detector 58 may be configured to monitor the temperature in the heating element. One or both of the substrate temperature detector 57 and the heater temperature detector 58 may also be used for over-temperature monitoring for safety purposes. The substrate temperature detector 57 and the heater temperature detector 58 may be implemented using any suitable temperature detector, such as an RTD, for example. Other potentially suitable temperature detectors include, among others, thermocouples and thermistors.

[0107] Additional temperature detectors may also be included. For example, when the heater 430 and the heater controller 56 are configured for control of an area of the substrate 10, additional temperature detectors may be included to facilitate in-area temperature control. Further, additional temperature detectors may be included to increase the accuracy of the measured temperature in the substrate 10 and / or the heater 430.

[0108] FIG. 12 shows another exemplary substrate processing apparatus configured to radiatively cool a substrate while the substrate is being processed, according to an embodiment of the present invention, where the processing moves the substrate laterally relative to a processing source using a mechanical arm. The substrate processing apparatus may be a particular implementation example of the upper substrate support apparatus described herein, such as the substrate support apparatus of FIG. 11, for example. Similarly labeled elements may be as described above.

[0109] Referring to FIG. 12, the substrate processing apparatus 1200 may be as described above, and includes a support assembly disposed in the processing chamber 50 and including a substrate holder 420. The substrate processing apparatus 1200 may be similar to the substrate processing apparatus 1100 of FIG. 11, except that the processing source 1152 is, in particular, a local processing source 1252, and the support assembly includes appropriate additional equipment (such as a mechanical arm 42, a rotational drive device 44, and a lateral movement rotational drive device 46) to enable the substrate 10 to be moved relative to the processing source 1152.

[0110] In addition, the substrate processing apparatus 1200 includes a vacuum pump 51, and the processing chamber 50 is, in particular, a vacuum processing chamber. A scanning controller 59 is also included to control the rotational drive device 44 and the lateral movement rotational drive device 46 to move the substrate 10 relative to the processing source 1152.

[0111] Here, exemplary embodiments of the present invention are summarized. Other embodiments can also be understood throughout this specification and from the claims appended hereto.

[0112] Example 1. A method of cooling a substrate during processing, the method comprising processing a substrate supported by a substrate holder, wherein the substrate is heated by the processing; cooling the substrate during processing by radiating heat from the substrate holder; and maintaining the substrate at a steady temperature within tolerance during processing by heating the substrate holder such that heat transferred from the substrate by radiating heat from the substrate holder is substantially balanced with heat transferred to the substrate by processing the substrate and by heating the substrate holder.

[0113] Example 2. The method according to Example 1, further comprising maintaining the substrate at a steady temperature by heating the substrate holder such that heat transferred from the substrate via heat radiation of the substrate holder is substantially balanced with heat transferred to the substrate by heating the substrate holder before processing the substrate.

[0114] Example 3. Maintaining the substrate holder at a steady temperature after removal of the substrate by heating the substrate holder, and processing a subsequent substrate supported by the substrate holder, wherein the subsequent substrate is heated by processing the subsequent substrate, processing the subsequent substrate, cooling the subsequent substrate by radiating heat from the substrate holder while processing the subsequent substrate, and maintaining the subsequent substrate at a steady temperature while processing the subsequent substrate by heating the substrate holder, further comprising the method according to any one of Examples 1 and 2.

[0115] Example 4. Maintaining the substrate holder at a steady temperature before processing the substrate includes heating the substrate holder to transfer thermal energy at a first rate, and maintaining the substrate at a steady temperature within tolerance during processing includes reducing the heating of the substrate holder to transfer thermal energy at a second rate less than the first rate to compensate for the heat transferred to the substrate by processing the substrate, the method according to Example 2.

[0116] Example 5. The method according to any one of Examples 1 to 4, including a wafer internal temperature change with a tolerance of less than about 4°C.

[0117] Example 6. The method according to any one of Examples 1 to 5, including a process temperature change with a tolerance of less than about 1°C.

[0118] Example 7. Monitoring the substrate by measuring the temperature during processing of the substrate, and dynamically adjusting the heating of the substrate holder to continue to maintain the substrate at a steady temperature in response to detecting a change in the measured temperature, further comprising the method according to any one of Examples 1 to 6.

[0119] Example 8. The method according to any one of Examples 1 to 7, wherein heat is not transferred from the substrate using a liquid during processing of the substrate.

[0120] Example 9. The method according to Example 8, wherein heat is not substantially transferred from the substrate via convection during processing of the substrate.

[0121] Example 10. The method according to any one of Examples 1 to 9, wherein processing the substrate includes moving the substrate laterally relative to a fixed local processing source using an arm attached to the substrate holder both while cooling the substrate and while heating the substrate holder to maintain the substrate at a constant temperature.

[0122] Example 11. A substrate holder, comprising: a chuck configured to immobilize a substrate on a first side of the chuck including a first material; a heater disposed on or within the chuck and configured to heat the substrate; and a second material disposed on a second side of the chuck opposite the first side, the second material including an exposed surface configured to cool the substrate by emitting thermal radiation, wherein the emissivity of the first material is lower than the emissivity of the second material.

[0123] Example 12. The substrate holder according to Example 11, wherein the substrate includes a main surface, and the first side of the entire chuck overlaps with the main surface of the substrate.

[0124] Example 13. The substrate holder according to any one of Examples 11 and 12, wherein the second material forms a plate attached to the second side of the chuck.

[0125] Example 14. The substrate holder according to any one of Examples 11 to 13, wherein the second material is a coating or film covering the second side of the chuck.

[0126] Example 15. The substrate holder according to Example 14, wherein the coating or film is a hard anodized coating.

[0127] Example 16. The substrate holder according to any one of Examples 14 and 15, wherein the coating or film is a high emissivity coating configured to provide chemical resistance.

[0128] Example 17. The substrate holder according to any one of Examples 11 to 16, wherein the second material is a high-emissivity ceramic.

[0129] Example 18. A substrate processing apparatus, comprising: a vacuum chamber; an electrostatic chuck (ESC) disposed in the vacuum chamber and having no liquid cooling mechanism, the ESC being configured to clamp a substrate on an upper surface of the ESC facing a local processing source; a heater integrated with the ESC and configured to heat the substrate during processing of the substrate; and a mechanical arm attached to the ESC and configured to move the substrate laterally with respect to the local processing source for processing the substrate.

[0130] Example 19. The substrate processing apparatus according to Example 18, further comprising: a first material including the upper surface of the ESC; and a second material including the lower surface of the ESC, the lower surface being an exposed surface configured to cool the substrate by emitting thermal radiation, and the emissivity of the first material being lower than the emissivity of the second material.

[0131] Example 20. The substrate processing apparatus according to Example 19, further comprising an overscan shield including an exposed upper surface extending laterally from an outer edge portion of the substrate, the exposed upper surface also including the second material.

[0132] Although the present invention has been described with reference to exemplary embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the exemplary embodiments, as well as other embodiments of the present invention, should be apparent to those skilled in the art upon reading the above description. Accordingly, the appended claims are intended to cover any such modifications or embodiments.

Claims

1. A method for cooling a substrate during processing, the method comprising: processing a substrate supported by a substrate holder, the substrate being heated by the processing; cooling the substrate during processing by radiating heat from the substrate holder; maintaining the substrate at a steady temperature within tolerance during processing by heating the substrate holder such that heat transferred from the substrate by radiating heat from the substrate holder substantially balances heat transferred to the substrate by processing the substrate and by heating the substrate holder; A method comprising the above steps.

2. The method according to claim 1, further comprising maintaining the substrate at the steady temperature by heating the substrate holder such that heat transferred from the substrate via heat radiation of the substrate holder substantially balances heat transferred to the substrate by heating the substrate holder, prior to processing the substrate.

3. maintaining the substrate holder at the steady temperature by heating the substrate holder after removal of the substrate; processing a subsequent substrate supported by the substrate holder, the subsequent substrate being heated by processing the subsequent substrate; cooling the subsequent substrate during processing by radiating heat from the substrate holder; maintaining the subsequent substrate at the steady temperature during processing the subsequent substrate by heating the substrate holder; The method according to claim 2, further comprising the above steps.

4. Maintaining the substrate holder at the steady temperature before processing the substrate includes heating the substrate holder to transfer thermal energy at a first rate. Maintaining the substrate within the tolerance at the steady temperature during processing includes reducing the heating of the substrate holder to transfer thermal energy at a second rate less than the first rate to compensate for the heat transferred to the substrate by processing the substrate. The method according to claim 2.

5. The method according to claim 1, wherein the tolerance includes a change in temperature within the wafer of less than about 4°C.

6. The method according to claim 1, wherein the tolerance includes a change in process temperature of less than about 1°C.

7. Monitoring the substrate by measuring the temperature during processing of the substrate; Dynamically adjusting the heating of the substrate holder to continue maintaining the substrate at the steady temperature in response to detecting a change in the measured temperature; The method according to claim 1, further comprising.

8. The method according to claim 1, wherein heat is not transferred from the substrate using a liquid during processing of the substrate.

9. The method according to claim 8, wherein heat is not substantially transferred from the substrate via convection during processing of the substrate.

10. Processing the substrate includes moving the substrate laterally relative to a fixed local processing source using an arm attached to the substrate holder both during cooling of the substrate and during heating of the substrate holder to maintain the substrate at the steady temperature. The method according to claim 1.

11. A substrate holder, A chuck configured to immobilize a substrate on a first side of the chuck including a first material; A heater disposed on or within the chuck and configured to heat the substrate; A second material disposed on a second side of the chuck opposite the first side, the second material including an exposed surface configured to cool the substrate by emitting thermal radiation, and the emissivity of the first material being lower than the emissivity of the second material. A second material; A substrate holder comprising.

12. The substrate holder according to claim 11, wherein the substrate includes a main surface and the entire first side of the chuck overlaps the main surface of the substrate.

13. The substrate holder according to claim 11, wherein the second material forms a plate attached to the second side of the chuck.

14. The substrate holder according to claim 11, wherein the second material is a coating or film covering the second side of the chuck.

15. The substrate holder according to claim 14, wherein the coating or film is a hard anodized coating.

16. The substrate holder according to claim 14, wherein the coating or film is a high emissivity coating configured to provide chemical resistance.

17. The substrate holder according to claim 11, wherein the second material is a high emissivity ceramic.

18. A substrate processing apparatus, A vacuum chamber, An electrostatic chuck (ESC) disposed in the vacuum chamber and having no liquid cooling mechanism, wherein the ESC is configured to clamp a substrate on an upper surface of the ESC facing a local processing source. A heater integrated with the ESC and configured to heat the substrate during processing of the substrate. A mechanical arm attached to the ESC and configured to move the substrate laterally with respect to the local processing source for processing the substrate. A substrate processing apparatus comprising the above.

19. A first material including the upper surface of the ESC. A second material including the lower surface of the ESC, wherein the lower surface is an exposed surface configured to cool the substrate by emitting thermal radiation, and the emissivity of the first material is lower than the emissivity of the second material. The substrate processing apparatus according to claim 18, comprising the above.

20. An overscan shield including an exposed upper surface extending laterally from an outer edge portion of the substrate, wherein the exposed upper surface also includes the second material. The substrate processing apparatus according to claim 19 further comprises the overscan shield.

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