Flexible platen and related methods

Abstract

1. A flexible platen comprising: an annular sidewall; a first layer coupled to the annular sidewall, the first layer having an associated first temperature control element; a second layer coupled to the annular sidewall, the second layer being disposed in a parallel spaced apart relationship with the first layer to define a gap between the first layer and the second layer, the second layer having an associated second temperature control element; and a controller coupled to the first and second temperature control elements, the controller configured to operate the first and second temperature control elements to vary temperatures of the first and second layers relative to one another and deflect the platen to more closely conform to an outline of the wafer.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE

[0001] Embodiments of the present disclosure relate generally to the field of semiconductor device manufacturing, and more particularly to a deflectable platen for facilitating effective clamping of a semiconductor wafer. [Background technology]

[0002]

[0002] Semiconductor wafers are typically placed on a flat platen during ion implantation and certain other processes performed during semiconductor device manufacturing. Generally, the semiconductor wafer is secured to the platen via an electrostatic clamp, where a voltage is applied between electrodes embedded within the platen, and the resulting electric field holds the semiconductor wafer to the platen. Electrostatic clamps are preferred over mechanical clamps, which can damage and / or contaminate the semiconductor wafer.

[0003] The ability of a platen to reliably clamp a semiconductor wafer to the platen via electrostatic clamping depends heavily on the proximity of the bottom surface of the semiconductor wafer to the top surface of the platen. Ideally, these surfaces are planar and positioned in close, continuous contact with one another. In some cases, semiconductor wafers may bow (e.g., bow up to 20 thousandths of an inch (20 thou)), resulting in a relatively large gap between the bottom surface of the semiconductor wafer and the top surface of the platen. This can weaken or render the electrostatic clamp ineffective. This problem can be exacerbated when the semiconductor wafer and platen are exposed to high-temperature or cryogenic processes (e.g., in high-temperature or cryogenic ion implantation). In such processes, incoherent bowing of the semiconductor wafer and platen can increase the size of the gap between them.

[0004]

[0004] Therefore, to promote reliable electrostatic clamping of a semiconductor wafer and a platen, it is desirable to minimize the surface-to-surface proximity therebetween. With regard to the above and other considerations, the improvements of the present invention may be useful. Summary of the Invention

[0005] This Summary is provided to introduce selected concepts in a simplified form. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter.

[0006]

[0006] An exemplary embodiment of a flexible platen according to the present disclosure may include an annular sidewall, a first layer coupled to the annular sidewall, the first layer having a first temperature control element associated therewith, and a second layer coupled to the annular sidewall, the second layer being positioned in a parallel spaced apart relationship with the first layer to define a gap between the first layer and the second layer, the second layer having a second temperature control element associated therewith.

[0007]

[0007] Another exemplary embodiment of a flexible platen according to the present disclosure may include an annular sidewall, a first layer coupled to the annular sidewall, the first layer having an associated first temperature control element, a second layer coupled to the annular sidewall, the second layer being positioned in a parallel spaced relationship with the first layer to define a gap therebetween, the second layer having an associated second temperature control element, and a controller coupled to the first and second temperature control elements, the controller configured to operate the first and second temperature control elements to vary the temperatures of the first and second layers relative to each other and deflect the platen to more closely match the contour of the wafer.

[0008]

[0008] One exemplary embodiment of a method for deflecting a platen according to the present disclosure may include providing an annular sidewall; providing a first layer coupled to the annular sidewall, the first layer having an associated first temperature control element; providing a second layer coupled to the annular sidewall, the second layer being positioned in a parallel spaced relationship with the first layer to define a gap between the first layer and the second layer, the second layer having an associated second temperature control element; and varying the temperature of at least one of the first layer and the second layer using the first temperature control element and the second temperature control element.

[0009] Various embodiments of the disclosed apparatus will now be described, by way of example, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0010] [Figure 1A]

[0010] FIG. 1 is a top view illustrating an exemplary embodiment of a flexible platen according to the present disclosure. [Figure 1B]

[0011] FIG. 1B is a cross-sectional side view of the flexible platen of FIG. 1A. [Figure 2A]

[0012] 1C is a cross-sectional side view of the flexible platen of FIGS. 1A and 1B with a convexly bowed semiconductor wafer positioned thereon. FIG. [Figure 2B]

[0013] 2B is a cross-sectional side view of the flexible platen of FIG. 2A in a convexly deflected state. [Figure 2C]

[0014] 1C is a cross-sectional side view of the flexible platen of FIGS. 1A and 1B in a concavely deflected state with a concavely deflected semiconductor wafer placed thereon. FIG. [Figure 3]

[0015] FIG. 1 is a flow diagram illustrating an exemplary embodiment of a method for deflecting a platen according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011]

[0016] Embodiments of the present disclosure will now be described more fully with reference to the accompanying drawings, which show some embodiments. The subject matter of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Such embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the subject matter to those skilled in the art. Like numbers refer to like elements throughout the drawings.

[0012]

[0017] 1A and 1B, there are shown a top view and a cross-sectional side view, respectively, of a flexible platen 10 (hereinafter referred to as "platen 10") according to an exemplary embodiment of the present disclosure. Platen 10 may be elastically deformable (as described in more detail below) to provide a close clearance relationship between the top surface of platen 10 and the bottom surface of a warped or bowed semiconductor wafer disposed thereon to facilitate effective clamping therebetween.

[0013]

[0018] The platen 10 may include a generally planar first layer 12 and a generally planar second layer 14 disposed in a parallel, vertically spaced apart relationship (i.e., spaced apart from each other in a direction parallel to the Y-axis shown in FIG. 1B ) to define a gap 15 between the first layer 12 and the second layer 14. Peripheral edges of the first layer 12 and the second layer 14 may be connected to an annular sidewall 16 that surrounds the first layer 12 and the second layer 14, as described in more detail below. In various examples, the first layer 12 and the second layer 14 may have a thickness of 6.0×10 -6 / ℃ and 8.0 × 10 -6 / °C. In certain embodiments, first layer 12 and second layer 14 may be formed of a ceramic (including, but not limited to, aluminum oxide, zirconia, or aluminum nitride). The present disclosure is not limited in this respect; alternatively, first layer 12 and / or second layer 14 may be formed of other materials having relatively high or low CTEs (including, but not limited to, aluminum, silver, copper, and alloys thereof, or quartz).

[0014]

[0019] The sidewalls 16 of the platen 10 may be formed of a dielectric material having a CTE lower than or similar to the CTE of the materials of the first layer 12 and the second layer 14. In various examples, the sidewalls 16 may be formed of a dielectric material having a CTE of 6.0×10 -6 / °C (e.g., 2.0 × 10 -6 / °C and 4.0 x 10 -6 The sidewalls 16 may be formed of a material having a CTE (between 1 / °C and 2 / °C). In certain embodiments, the sidewalls 16 may be formed of a ceramic (e.g., aluminum nitride or aluminum oxide). The present disclosure is not limited in this respect; alternatively, the sidewalls 16 may be formed of other dielectric materials (including, but not limited to, other ceramics and various composite materials). The sidewalls 16 may be connected to the edges of the first and second layers 12, 14 by brazing, welding, high-temperature adhesives, various mechanical fasteners, glass bonding, and / or other techniques suitable for bonding or fastening the material of the sidewalls 16 to the materials of the first and second layers 12, 14. As described in more detail below, the sidewalls 16 may mechanically transfer the expansion and contraction of the first and second layers 12, 14 to each other.

[0015]

[0020] The first layer 12 and the second layer 14 may each include a first heating element 20 and a second heating element 22 associated therewith. For example, in the platen embodiment shown in FIG. 1B , the first heating element 20 and the second heating element 22 may be embedded within the first layer 12 and the second layer 14. The first heating element 20 and the second heating element 22 may include one or more wires, cables, plates, tapes, etc. connected to one or more power sources (not shown). The first heating element 20 and the second heating element 22 may be independently operable to selectively and independently heat the first layer 20 and the second layer 22. In various examples, the first heating element 20 and the second heating element 22 may heat the first layer 12 and the second layer 14, respectively, to a temperature greater than 800 degrees Celsius (e.g., in the range of 800 degrees Celsius to 1200 degrees Celsius). The present disclosure is not limited in this respect. The gap 15 separating the first layer 12 and the second layer 14 may be held at a vacuum or near a vacuum, thus providing thermal isolation between the first layer 12 and the second layer 14. In particular, the gap 15 may prevent all or a majority of the heat generated by the first heating element 20 from being transferred to the second layer 14, and may prevent all or a majority of the heat generated by the second heating element 22 from being transferred to the first layer 12. In various embodiments, the platen 10 may additionally or alternatively include one or more layers of insulating material disposed between the first layer 12 and the second layer 14.

[0016]

[0021] The second layer 14 of the platen 10 may have a plurality of electrodes 23 associated with it. For example, in the platen embodiment shown in FIG. 1B, the electrodes 23 may be embedded within the second layer 14. In various alternative embodiments of the platen 10, the electrodes 23 may be embedded within a separate layer of dielectric material disposed above the second layer 14. The present disclosure is not limited in this respect. The electrodes 23 may be connected to a power source (not shown) and may be positioned and configured to operate in the manner of a conventional electrostatic clamp known to those skilled in the art. In particular, applying a voltage across the electrodes 23 generates an electric field that may hold the semiconductor wafer to the platen 10 via electrostatic force. The strength of the electrostatic force acting on the wafer depends in part on the proximity of the wafer to the electrodes 23. Ideally, for example, if the bottom surface of the wafer and the top surface of the platen 10 are planar or nearly planar, the contour of the bottom surface of the wafer matches or nearly matches the contour of the top surface of the platen 10, thus establishing the shortest possible distance between the electrode 23 and the wafer to provide a strong electrostatic coupling therebetween. In some cases, a wafer, such as the semiconductor wafer 24 (hereinafter referred to as "wafer 24") shown in FIG. 2A, may be warped or bowed (e.g., bowing up to 20 shou, and in some cases even more), causing its bottom surface to appear concave relative to the substantially planar top surface of the platen 10 (the bowing of the wafer 24 shown in FIG. 2A is exaggerated for illustrative purposes). The resulting gap 25 between the wafer 24 and the platen 10 may attenuate the electrostatic force acting on the wafer 24, thereby weakening the electrostatic clamping between the platen 10 and the wafer 24.

[0017]

[0022] In various alternative embodiments of the platen 10, the electrode 23 may be omitted, and the wafer 24 may be secured to the upper surface of the platen 10 using a variety of mechanical clamps 27 (shown in dashed lines in FIG. 1B ) known to those skilled in the art. As with electrostatic coupling, ideally, the contours of the bottom surface of the wafer 24 and the top surface of the platen 10 will match or nearly match, for example, if the bottom surface of the wafer and the top surface of the platen 10 are planar or nearly planar, to promote optimal contact between these surfaces and a reliable mechanical interlock, as well as optimal thermal coupling between the platen 10 and the wafer 24. Good thermal coupling may be desirable when the platen 10 is configured to heat or cool a wafer placed thereon (e.g., by heat transfer via an inert gas introduced between the platen 10 and the wafer 24). If the wafer 24 warps or bends, the resulting gap 25 between the wafer 24 and the platen 10 can be detrimental to providing a reliable mechanical clamp and / or establishing an effective thermal bond between the wafer 24 and the platen 10.

[0018]

[0023] Referring to FIG. 2B, the platen 10 is shown in a convexly deflected state. Specifically, the second heating element 22 is activated and the first heating element 20 is deactivated or activated at a low power, such that the first layer 12 is unheated or heated to a lower temperature than the second layer 14 while the second layer 14 is heated. When heated, the second layer 14 may exhibit thermal expansion according to its CTE. Because the second layer 14 is connected to the first layer 12 by the sidewalls 16 and the unheated first layer 12 does not expand (or expands at a slower rate and / or to a lesser extent than the heated second layer 14), the radial expansion of the second layer 14 may cause the upper portion of the sidewalls 16 to deflect outward, which in turn may pull or deflect the edges of the first layer 12 and second layer 14 downward, resulting in the convex deflection of the platen 10 shown in FIG. 2B. Thus, the contours of the top surface of the platen 10 and the bottom surface of the wafer 24 may more closely match, reducing the size of the gap 25 between the top surface of the platen 10 and the bottom surface of the wafer 24 compared to the undeflected state of the platen 10 shown in FIG. 2A. In the case of electrostatic clamping, the reduced gap 25 and closer proximity of the electrode 23 to the wafer 24 facilitated by the deflection of the platen 10 enhances the electrostatic force acting on the wafer 24 compared to the electrostatic force applied by the undeflected platen 10 shown in FIG. 2A, thereby resulting in improved electrostatic coupling between the platen 10 and the wafer 24. In the case of mechanical clamping, the reduced gap 25 achieved by the deflection of the platen 10 provides more secure clamping of the wafer 24 to the platen 10 and improves thermal coupling between the platen 10 and the wafer 24 compared to the undeflected platen 10 shown in FIG. 2A.

[0019]

[0024] Platen 10 may also bend in a concave direction to accommodate a semiconductor wafer that has a bow or bow that presents a convex surface relative to the top surface of platen 10. For example, referring to FIG. 2C, platen 10 is shown in a concavely bowed state, with a concavely bowed semiconductor wafer 28 (hereinafter "wafer 28") disposed thereon. Specifically, first heating element 20 is activated and second heating element 22 is not activated (or is activated at a lower power), thereby heating first layer 12 relative to second layer 14. When heated, first layer 12 may exhibit thermal expansion according to its CTE. Because the first layer 12 is connected to the second layer 14 by the sidewalls 16, and the unheated second layer 14 does not expand (or expands at a slower rate and / or to a lesser extent than the heated first layer 12), the radial expansion of the first layer 12 may cause the lower portions of the sidewalls 16 to bow outward, which in turn may pull or bow the edges of the first and second layers 12, 14 upward, resulting in the concave bow of the platen 10 shown in FIG. 2C. Thus, the contours of the top surface of the platen 10 and the bottom surface of the wafer 28 may more closely match, which in turn may improve the electrostatic coupling or mechanical interlock between the platen 10 and the wafer 28, as described above.

[0020]

[0025] In various examples, the first layer 12 and the second layer 14 can be heated to a temperature between 300 degrees Celsius and 800 degrees Celsius to achieve the target deflection. In a specific, non-limiting example, the platen 10 exhibits a convex deflection of 18 thou when the second layer is heated to a temperature of 500 degrees Celsius and a convex deflection of 18 thou when the first layer is heated to a temperature of 500 degrees Celsius. Concave The platen 10 may exhibit a flexural deflection. The present disclosure is not limited in this regard. The degree of deflection of the platen 10 depends on several factors, including, but not limited to, the CTE of the first and second layers 12 and 14, the amount of heat applied to the first and second layers 12 and 14, the diameter of the first and second layers 12 and 14, and the thickness of the first and second layers 12 and 14.

[0021]

[0026] In various embodiments, the deflection stress of either the first layer 12 or the second layer 14 during heating can be less than the yield strength of the material of the first layer 12 or the second layer 14. Thus, when the first layer 12 or the second layer 14 is allowed to cool to room temperature, the platen 10 can return to its original, substantially planar state shown in FIG. 1B. Thus, by varying the amount of heat applied to the first layer 12 or the second layer 14, the platen 10 can be controllably deflected to different degrees (e.g., from 0 to 20 thou) in either direction (i.e., in the concave or convex direction) to conform to or approximate the contours of wafers having various degrees of deflection and provide an effective electrostatic or mechanical clamp between the platen 10 and the wafer. Thus, the deflection of the incoming wafer may be measured (e.g., by contact sensors, image analysis, etc.), and a controller 29 operably coupled to the platen 10, upon receiving data representing the measured wafer deflection, may direct the operation of the first heating element 20 and the second heating element 22 to deflect the platen 10 to conform to or approximate the contour of the incoming wafer.

[0022]

[0027] While the platen 10 has been described above as including embedded first and second heating elements 20, 22 for controllably and selectively heating the first and second layers 12, 14, various alternative embodiments of the platen 10 are contemplated. In such embodiments, the first and second heating elements 20, 22 described and illustrated above may be replaced by cooling elements for controllably and selectively cooling the first and second layers 12, 14. As such, the first and second heating elements 20, 22 may alternatively be referred to herein as “cooling elements 20, 22,” or more generally as “temperature control elements 20, 22.” The cooling elements may be or include various channels, conduits, tubes, pipes, ducts, etc. embedded in, disposed on, or extending through the first and second layers 12, 14 for passing and circulating a cooling fluid (e.g., water, liquid nitrogen, etc.). The cooling elements 20, 22 may be used to cool the first layer 12 and / or the second layer 14, for example, to a temperature within a range between 0 degrees Celsius and −150 degrees Celsius. By cooling one of the first layer 12 and the second layer 14 and not cooling the other of the first layer 12 and the second layer 14, the cooled layer may exhibit thermal contraction according to its CTE. Because the first layer 12 and the second layer 14 are connected to each other by the sidewalls 16 and the uncooled layer does not contract (or contracts at a slower rate and / or to a lesser extent than the cooled layer), the radial contraction of the cooled layer may cause the sidewalls 16 to bow, which in turn may pull or bow the edges of the first layer 12 and the second layer 14 upward or downward depending on the cooled layer, resulting in the concave or convex bowing of the platen 10 shown in FIGS. 2B and 2C . In various other embodiments, the first layer 12 and the second layer 14 may include heating and cooling elements similar to those described above.

[0023]

[0028] 3, a flow diagram illustrating one exemplary method for deflecting a platen according to the present disclosure is shown, which will now be described in light of the illustration of platen 10 shown in FIGS. 1A-2C.

[0024]

[0029] At block 100 of the exemplary method, first and second layers 12, 14 are provided and may be coupled to annular sidewall 16 by, for example, brazing, welding, heat-resistant adhesives, various mechanical fasteners, glass bonding, and / or other techniques suitable for joining or fastening the material of sidewall 16 to the material of first and second layers 12, 14. First and second layers 12, 14 may be disposed in a parallel, spaced-apart relationship defining a gap 15 therebetween, which may be held at a vacuum or near-vacuum to provide thermal insulation between first and second layers 12, 14. First and second layers 12, 14 may each include a first and second temperature control element 20, 22 associated therewith (e.g., embedded therein). In block 110 of the exemplary method, the second layer 14 may be provided with an electrode 23 associated with (e.g., embedded within) the second layer 14 to facilitate electrostatic clamping of the wafer to the platen 10. In various alternative embodiments, the electrode 23 may be omitted and a mechanical clamp 27 may be implemented.

[0025]

[0030] In block 120 of the exemplary method, the deflection of the incoming wafer may be measured (e.g., by contact sensors, imaging, etc.), and a controller 29 operably coupled to the platen 10, upon receiving data representing the measured wafer deflection, may direct operation of the first temperature control element 20 and the second temperature control element 22 to deflect the platen 10 to conform to or approximate the contour of the incoming wafer. In one example where the first temperature control element 20 and the second temperature control element 22 are heating elements, the second temperature control element 22 may be operable in block 130a of the exemplary method to heat the second layer 14 relative to the first layer 12. When heated, the second layer 14 may exhibit thermal expansion according to its CTE. Because the second layer 14 is connected to the first layer 12 by the sidewalls 16, and the unheated first layer 12 does not expand (or expands at a slower rate and / or to a lesser extent than the heated second layer 14), the radial expansion of the second layer 14 may cause the upper portions of the sidewalls 16 to bow outward, which in turn may pull or bow the edges of the first and second layers 12, 14 downward, resulting in the convex bow of the platen 10 shown in FIG. 2B. This may result in a closer match between the contour of the top surface of the platen 10 and the contour of the bottom surface of the incoming wafer.

[0026]

[0031] In another example where the first temperature control element 20 and the second temperature control element 22 are heating elements, the first temperature control element 20 may be activated to heat the first layer 12 relative to the second layer 14 in block 130b of the exemplary method. When heated, the first layer 12 may exhibit thermal expansion according to its CTE. Because the first layer 12 is connected to the second layer 14 by the sidewall 16 and the unheated second layer 14 does not expand (or expands at a slower rate and / or to a lesser extent than the first layer 12), the radial expansion of the first layer 12 may cause the lower portion of the sidewall 16 to bow outward, which in turn may pull or bow the edges of the first layer 12 and second layer 14 upward, resulting in the concave bow of the platen 10 shown in FIG. 2C . This may result in a closer match between the contour of the top surface of the platen 10 and the contour of the incoming wafer.

[0027]

[0032] In another example where the first temperature control element 20 and the second temperature control element 22 are cooling elements, the first temperature control element 20 may be operated to cool the first layer 12 relative to the second layer 14 in block 130c of the exemplary method. Once cooled, the first layer 12 may exhibit thermal contraction according to its CTE. Because the first layer 12 is connected to the second layer 14 by the sidewalls 16 and the uncooled second layer 14 does not contract (or contracts at a slower rate and / or to a lesser extent than the first layer 12), the radial contraction of the first layer 12 may cause the lower portions of the sidewalls 16 to bow inward, which in turn may pull or bow the edges of the first layer 12 and second layer 14 downward, resulting in the convex bow of the platen 10 shown in FIG. 2B . This may result in a closer match between the contour of the top surface of the platen 10 and the contour of the incoming wafer.

[0028]

[0033] In another example where the first temperature control element 20 and the second temperature control element 22 are cooling elements, the second temperature control element 22 may be actuated in block 130d of the exemplary method to cool the second layer 14 relative to the first layer 12. Once cooled, the second layer 14 may exhibit thermal contraction according to its CTE. Because the second layer 14 is connected to the first layer 12 by the sidewalls 16 and the uncooled first layer 12 does not contract (or contracts at a slower rate and / or to a lesser extent than the cooled second layer 14), the radial contraction of the second layer 14 may cause the upper portions of the sidewalls 16 to bow inward, which in turn may pull or bow the edges of the first layer 12 and the second layer 14 upward, resulting in the concave bow of the platen 10 shown in FIG. 2C . Thus, the contour of the top surface of the platen 10 can more closely match the contour of the bottom surface of the incoming wafer.

[0029]

[0034] As will be recognized by those skilled in the art, the above-described flexible platen 10 offers distinct advantages over conventional platens. For example, the platen 10 can be selectively and dynamically deflected through controlled application of heat (or cooling) to the first layer 12 and the second layer 14, thereby quickly and easily facilitating effective clamping with wafers having various degrees of concave or convex deflection. Furthermore, the ability of the platen 10 to conform to the contours of a wafer placed thereon promotes effective heat transfer between the platen 10 and the wafer (e.g., for heating and / or cooling the wafer).

[0030]

[0035] The present disclosure is not limited in scope by the specific embodiments described herein. Indeed, various other embodiments and modifications of the present disclosure, in addition to the embodiments described herein, will be apparent to those skilled in the art from the foregoing description and the accompanying drawings. Accordingly, such other embodiments and modifications are intended to be included within the scope of the present disclosure. Moreover, while the present disclosure has been described herein in terms of particular implementations in particular environments for particular purposes, those skilled in the art will recognize that the usefulness of the present disclosure is not limited in this respect. Embodiments of the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in light of the full scope and nature of the present disclosure as described herein.

Claims

1. a flexible platen, an annular sidewall; a first layer coupled to the annular sidewall, the first layer having a first temperature control element associated therewith; a second layer coupled to the annular sidewall, the second layer being disposed in a parallel spaced apart relationship with the first layer to define a gap therebetween that provides thermal insulation between the first and second layers, the second layer having a second temperature control element associated therewith.

2. The flexible platen of claim 1 further comprising a plurality of electrodes associated with the second layer for facilitating electrostatic clamping of a wafer to the flexible platen.

3. The flexible platen of claim 1 , wherein the first and second temperature control elements are first and second heating elements.

4. The flexible platen of claim 3 , wherein the first heating element and the second heating element comprise one or more of a wire, a cable, a plate, and a tape connected to one or more power sources.

5. 4. The flexible platen of claim 3, wherein the first heating element and the second heating element are independently controllable to independently heat the first layer and the second layer to a temperature above 800 degrees Celsius.

6. The flexible platen of claim 1 , wherein the first and second temperature control elements are first and second cooling elements.

7. The flexible platen of claim 6 , wherein the first cooling element and the second cooling element comprise one or more of channels, conduits, tubes, pipes, and ducts for circulating a cooling fluid.

8. 7. The flexible platen of claim 6, wherein the first cooling element and the second cooling element are independently controllable to independently cool the first layer and the second layer to temperatures within a range of 0 degrees Celsius to -150 degrees Celsius.

9. The first layer and the second layer are 6.0 × 10 －６ / ℃ and 8.0 × 10 －６ 10. The flexible platen of claim 1, wherein the flexible platen is formed of a material having a coefficient of thermal expansion in the range between 1000 and 1000°C.

10. The side wall is 6.0 × 10 －６ 10. The flexible platen of claim 1, wherein the flexible platen is formed of a material having a coefficient of thermal expansion of less than 1 / °C.

11. The flexible platen of claim 1 , wherein the gap is a vacuum.

12. a flexible platen, an annular sidewall; a first layer coupled to the annular sidewall, the first layer having a first temperature control element associated therewith; a second layer coupled to the annular sidewall, the second layer being disposed in parallel spaced relation to the first layer to define a gap therebetween that provides thermal insulation between the first and second layers, the second layer having a second temperature control element associated therewith; a controller coupled to a first temperature control element and the second temperature control element, the controller configured to operate the first temperature control element and the second temperature control element to vary the temperatures of the first layer and the second layer relative to one another and to deflect the flexible platen to more closely conform to the contour of a wafer.

13. 1. A method of deflecting a platen, comprising: providing an annular sidewall; providing a first layer coupled to the annular sidewall, the first layer having a first temperature control element associated therewith; providing a second layer coupled to the annular sidewall, the second layer being disposed in parallel spaced relation to the first layer to define a gap therebetween that provides thermal insulation between the first and second layers, the second layer having a second temperature control element associated therewith; and varying a temperature of at least one of the first layer and the second layer using the first temperature control element and the second temperature control element.

14. 14. The method of claim 13, further comprising providing the second layer with an electrode associated with the second layer to facilitate electrostatic clamping of the wafer to the platen.

15. 14. The method of claim 13, wherein the first and second temperature control elements are first and second heating elements, and the method further comprises activating the second heating element to heat the second layer relative to the first layer, thereby causing thermal expansion of the second layer and convex deflection of the platen.

16. 14. The method of claim 13, wherein the first and second temperature control elements are first and second heating elements, and the method further comprises activating the first heating element to heat the first layer relative to the second layer, thereby causing thermal expansion of the first layer and concave deflection of the platen.

17. 14. The method of claim 13, wherein the first temperature control element and the second temperature control element are a first cooling element and a second cooling element, the method further comprising: activating the second cooling element to cool the second layer relative to the first layer, thereby causing thermal contraction of the second layer and concave deflection of the platen.

18. 14. The method of claim 13, wherein the first and second temperature control elements are first and second cooling elements, and the method further comprises activating the first cooling element to cool the first layer relative to the second layer, thereby causing thermal contraction of the first layer and convex deflection of the platen.

19. measuring the deflection of a wafer to be placed on the platen; communicating data representative of the measured wafer deflection to a controller operatively connected to the first temperature control element and the second temperature control element; 14. The method of claim 13, further comprising: actuating, via the controller, at least one of the first temperature control element and the second temperature control element to vary the temperatures of the first layer and the second layer and to deflect the platen to more closely conform to the contour of the wafer.

20. 20. The method of claim 19, wherein the wafer deflection is measured using one of a contact sensor and image analysis.

Images