Heat spreader for semiconductor wafer holder

Abstract

The electrostatic chuck is formed by forming a diffusion layer on an electrostatic puck and removing regions of the diffusion layer to form discrete diffusion segments separated by gaps. The discrete diffusion segments can consist of continuous concentric circles, discontinuous concentric circles, or a combination of continuous and discontinuous concentric circles. The discrete diffusion segments are separated from one another by forming at least one groove in the diffusion layer. The groove can extend partially through the diffusion layer, extend completely through the diffusion layer to the electrostatic puck, or have a first portion that extends partially through the diffusion layer and a second portion that extends completely through the diffusion layer. The groove can have a constant width or a variable width.

Description

Detailed Description of the Invention

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. Application No. 16 / 552,790, "Heat Spreader for Semiconductor Wafer Holder," filed August 27, 2019, the contents of which are incorporated by reference in their entirety herein. [Technical field]

[0002] FIELD OF THE DISCLOSURE This disclosure relates to electrostatic chucks, and more generally to ceramic chucks having multiple heating zones. [Background technology]

[0003] The statements in this section are merely intended to provide background information related to the present disclosure and may not constitute prior art.

[0004] Wafer support assemblies, such as electrostatic chucks (also referred to herein as "E-chucks"), may be used in semiconductor processing to support and hold a wafer thereon. For example, an E-chuck may include an electrostatic puck (also referred to herein as "E-puck") that applies an electrostatic clamping force to the wafer. The E-chuck is typically exposed to high heat in plasma processing chambers that perform various wafer processing / treatment steps, such as chemical vapor deposition (CVD), etching, sputtering, and ion implantation. The E-chuck may be heated by a heater built into the E-chuck. A cooling device is typically located below the E-chuck to regulate or reduce the temperature of the E-chuck during wafer processing or after wafer processing is completed. During wafer processing, the E-chuck is exposed to wide and rapid temperature changes, while the wafer temperature must be controlled to very tight tolerances, such as less than about 0.5° C. during etching processes (e.g., processing temperatures up to about 120° C.) and less than about 5° C. during deposition (deposition) processes (e.g., processing temperatures ranging from about 400 to 700° C.).

[0005] These problems of controlling the temperature of a wafer during semiconductor processing, among other problems related to semiconductor processing, are addressed by the present disclosure. Summary of the Invention

[0006] This section provides a general overview of the disclosure and is not a comprehensive disclosure of its entire scope or all of its features.

[0007] In one aspect of the disclosure, the E-chuck is formed by forming a diffusion layer on the E-pack, removing regions of the diffusion layer to form discrete diffusion segments separated by gaps, bonding the E-pack to a heater such that the diffusion layer is disposed between the electrostatic pack and the heater, and bonding the heater to a cold plate. In one variation, the discrete diffusion segments form continuous concentric circles, and in another variation, the discrete diffusion segments form discontinuous concentric circles. In yet another variation, the discrete diffusion segments are defined by a combination of continuous and discontinuous concentric circles. In at least one aspect of the disclosure, the discrete diffusion segments are separated by forming at least one groove in the diffusion layer. In one variation, the at least one groove extends partially through the diffusion layer, and in another variation, the at least one groove extends completely through the diffusion layer to the E-pack. In yet another variation, the at least one groove defines a variable depth, having a first portion that extends partially through the diffusion layer and a second portion that extends completely through the diffusion layer. Also, in some variations, at least one groove defines a constant width, while in other variations, at least one groove defines a variable width.

[0008] In at least one embodiment of the present disclosure, the at least one groove is formed by one of acid etching, laser cutting, machining, and the like, among others.

[0009] In at least one embodiment, the electrostatic puck is a ceramic material.

[0010] In accordance with an embodiment of the present disclosure, the heater includes at least two heating zones, and the diffusion ring is axially aligned with the at least two heating zones such that the at least two heating zones are thermally decoupled from one another.

[0011] In another aspect of the disclosure, the heater includes an outer heating zone and an inner heating zone, and the diffusion ring is axially aligned with the outer heating zone and the inner heating zone to thermally decouple the outer heating zone from the inner heating zone, thereby maintaining a desired thermal gradient between the outer heating zone and the inner heating zone during heating of a target on the electrostatic puck.

[0012] The diffusion layer is formed from a highly thermally conductive material, such as one of the following materials: aluminum, molybdenum, tungsten, nickel, zinc, silicon, and alloys thereof. For example, in one version, the diffusion layer is formed from aluminum and has a thickness of less than 0.040 inches (1.02 mm).

[0013] In one aspect of the present disclosure, the diffusion layer is formed by cold spraying aluminum directly onto an electrostatic puck, and the heating layer is a foil heater, a layered heater, or a damascene heater. For example, in one form the heater is a polyimide heater and the E-pack is bonded to the polyimide heater with an elastomer.

[0014] In one aspect of the present disclosure, the E-chuck includes a base plate, and the polyimide heater is bonded to the base plate with an elastomer.

[0015] In another aspect of the disclosure, an E-chuck is formed by a process that includes forming a diffusion layer on an E-pack, cutting at least one groove in the diffusion layer, and forming at least two concentric diffusion rings on the E-pack, radially spaced apart to define a predetermined spacing. The E-pack is bonded to a polyimide heater having at least two heating zones, and the at least two diffusion rings are disposed between the E-pack and the polyimide heater. The polyimide heater is bonded to a cooling plate, and the at least two diffusion rings are axially aligned with the at least two heating zones such that the at least two heating zones are thermally decoupled from one another during heating of a target on the electrostatic pack.

[0016] In at least one variation, the at least two heating zones include an outer heating zone and an inner heating zone, and a desired thermal gradient is maintained between the outer heating zone and the inner heating zone during heating of the target on the electrostatic ceramic puck.

[0017] In one variation, the E-pack is bonded to the polyimide heater with a first elastomer layer, and the polyimide heater is bonded to the base plate with a second elastomer layer, and a diffusion layer is formed on the E-pack by cold spraying aluminum directly onto the electrostatic pack, the diffusion layer having a thickness of less than 0.040 inches (11.0 mm).

[0018] In another aspect of the disclosure, a method for providing heat to a target portion includes mounting the target portion to a chuck using an E-pack bonded to a heater having at least two heating zones. At least two diffusion rings are formed from a diffusion layer bonded to the E-pack, the at least two diffusion rings being disposed between the E-pack and the heater. The at least two diffusion rings are concentrically disposed on the E-pack and radially spaced apart to define a predetermined spacing. The heater is energized to transfer heat from the at least two heating zones to the target portion, the at least two diffusion rings thermally decoupling the at least two heating zones. A desired thermal gradient is thereby maintained between the at least two heating zones during heating of the target portion.

[0019] In one variation, the heater is a polyimide heater, the at least two diffuser rings are bonded to the polyimide heater with a first elastomer layer, and the polyimide heater is bonded to the base plate with a second elastomer layer.

[0020] In another variation, the polyimide heater includes a heating layer, a dielectric layer, and a routing layer, a first elastomer layer disposed between the at least two diffusion rings and the dielectric layer, and a second elastomer layer disposed between the routing layer and the base plate.

[0021] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. [Brief description of the drawings]

[0022] In order that the present disclosure may be better understood, various forms thereof will now be described, given by way of example only, with reference to the accompanying drawings, in which:

[0023] [Figure 1A] FIG. 1A is a cross-sectional view of an E-chuck constructed in accordance with one embodiment of the present disclosure.

[0024] [Figure 1B] FIG. 1B is a cross-sectional view of an E-chuck constructed in accordance with another embodiment of the present disclosure.

[0025] FIG. 2 depicts a sequence of steps for a method of manufacturing an E-chuck according to the present disclosure. [Figure 2A] FIG. 2A is a cross-sectional view of an E-pack. [Figure 2B] FIG. 2B is a cross-sectional view of the E-pack of FIG. 2A with a diffusion layer (diffusion layer) formed thereon. [Figure 2C] FIG. 2C is a cross-sectional view of the E-pack of FIG. 2B, with a trench formed in the diffusion layer. [Figure 2D] FIG. 2D is a cross-sectional view of the E-pack of FIG. 2C, in which discrete diffusion segments are formed in the diffusion layer. [Figure 2E] FIG. 2E is a cross-sectional view of the E-pack of FIG. 2D having a diffusion layer that has been machined to a reduced thickness. [Figure 2F] FIG. 2F is a top view of the E-pack of FIG. 2E having discrete diffusion segments formed in the diffusion layer. [Figure 2G] FIG. 2G is a cross-sectional view of an assembly of the E-pack of FIG. 2F with a heater and cooling plate.

[0026] FIG. 3 depicts a series of diffusion layers with trenches that form discrete diffusion segments. [Figure 3A] FIG. 3A is a cross-sectional view of a rectangular groove extending into and through the diffusion layer. [Figure 3B] FIG. 3B is a cross-sectional view of a rectangular groove extending into the diffusion layer. [Figure 3C] FIG. 3C is a cross-sectional view of a hemispherical groove extending into the diffusion layer. [Figure 3D] FIG. 3D is a cross-sectional view of a V-shaped groove extending into the diffusion layer.

[0027] [Figure 4] FIG. 4 is a plan view of a diffusion layer having discrete diffusion segments according to one embodiment of the present disclosure.

[0028] [Diagram 5] FIG. 5 is a plan view of a diffusion layer having discrete diffusion segments according to another embodiment of the present disclosure.

[0029] [Figure 6] FIG. 6 is a plan view of a diffusion layer having discrete diffusion segments according to yet another embodiment of the present disclosure.

[0030] [Figure 7] FIG. 7 is a graph illustrating E-pack ceramic surface temperature and E-pack ceramic surface temperature range as a function of diffusion layer thickness in accordance with the teachings of the present disclosure.

[0031] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] The following description is merely illustrative and is not intended to limit the disclosure, application, or uses. It is understood that throughout the drawings, corresponding reference characters indicate similar or corresponding parts and features. Examples are provided to fully convey the scope of the disclosure to those skilled in the art. Numerous specific details are described, such as specific components, types of devices, and methods, to provide a thorough understanding of the variations of the disclosure. It will be apparent to those skilled in the art that specific details need not be employed, and the examples provided herein may include alternative embodiments, and are not intended to limit the scope of the disclosure. In some examples, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0033] FIG. 1A shows an E-chuck 2 constructed according to one aspect of the present disclosure. The E-chuck 2 includes an E-pack 10, a diffusion layer 20, an upper bonding layer 30, a heater 40, a lower bonding layer 42, and a cooling plate 60. In this embodiment, the heater 40 is an etched foil heater including a polyimide layer 35 (or "interlayer dielectric") and an etched foil heater circuit 44 on the polyimide layer 35. However, it should be understood that other heater structures may be employed while remaining within the scope of the present disclosure. Furthermore, both the upper and lower bonding layers 30 / 42 may be optional, provided that a suitable dielectric is provided around the heater circuit 44, which is directly secured to the diffusion layer 20 and the cooling plate 60.

[0034] Typically, the E-chuck 2 is used as part of a support member in a semiconductor processing pedestal assembly, however, it should be understood that the teachings of the present disclosure may be employed in other applications besides semiconductor processing equipment, such as, by way of example, industrial manufacturing equipment, countertops, and medical equipment, while remaining within the scope of the present disclosure.

[0035] E-chuck 10 includes a substrate 12 and an electrode 4 embedded within substrate 12. Substrate 12 is defined with a first surface 6 and a second surface 8, the latter of which is for heating a target (i.e., a wafer) thereon. In at least one aspect of the present disclosure, substrate 12 is formed from a ceramic material, such as aluminum oxide (Al2O3) or aluminum nitride (AlN). However, it should be understood that other ceramic or non-ceramic materials may be employed while remaining within the scope of the present disclosure.

[0036] The diffusion layer 20 is disposed between the E-pack 10 and the heater 40. The diffusion layer 20 defines a first surface 22 and a second surface 24. The first surface 22 is disposed directly on the first surface 6 of the E-pack 10. The second surface 24 is disposed on the heater 40. In one variation, the second surface 24 of the diffusion layer 20 may be disposed directly on the interlayer dielectric 35 of the heater 40 such that the heater 40 is secured directly to the diffusion layer 20. In another variation, a bonding layer 30 may be disposed between the diffusion layer 20 and the heater 40 such that the heater 40 is secured to the diffusion layer 20.

[0037] As further shown, the diffusion layer 20 includes at least one trench or gap 26. The trench 26 defines discrete diffusion segments 28 within the diffusion layer 20, as will be described in more detail below. In general, the diffusion layer 20 enhances temperature uniformity at the second surface 8 of the E-pack 10. Meanwhile, the discrete diffusion segments 28 allow for a desired temperature gradient to be maintained between segments during heating of a target on the E-pack 10, as will be described in more detail below.

[0038] 1B shows an E-chuck 10 constructed in accordance with another embodiment of the present disclosure, which generally includes a routing layer. The E-chuck 10 generally includes an E-pack 100, a diffusion layer 120, a dielectric layer 135, a heater 140, a routing layer 146, and a cooling plate 160.

[0039] The E-pack 100 includes a substrate 102 and an electrode 104 embedded within the substrate 102. The substrate 102 defines a first surface 106 and a second surface 108 for heating a target thereon. In at least one embodiment of the present disclosure, the substrate 102 is formed from a ceramic material, such as aluminum oxide (Al2O3) or aluminum nitride (AlN).

[0040] The diffusion layer 120 is disposed between the E-pack 100 and the dielectric layer 135. The diffusion layer 120 defines a first surface 122 and a second surface 124. The first surface 122 is disposed directly on the E-pack 100 and the second surface 124 is disposed on the dielectric layer 135.

[0041] As further shown, the diffusion layer 120 includes at least one trench or gap 126. The trench 126 is provided to form discrete diffusion segments 128 in the diffusion layer 120, which are shown in more detail in FIGS. 3-6. As will be described in more detail below, the diffusion layer 120 enhances temperature uniformity at the second surface 108 of the E-pack 100. Meanwhile, the discrete diffusion segments 128 allow a desired thermal gradient to be maintained between segments during heating of a target on the E-pack 100.

[0042] The dielectric layer 135 is disposed between the diffusion layer 120 and the heater 140. In at least one variation of the present disclosure, the bonding layer 130 is disposed between the diffusion layer 120 and the dielectric layer 135. It should be understood that the bonding layer 130 bonds or adheres the E-pack 100 having the diffusion layer 120 to the dielectric layer 135. However, it should be understood that the diffusion layer 120 may be disposed directly on the E-pack 100 without the bonding layer 130 while remaining within the scope of the present disclosure. In such a configuration, the diffusion layer 120 may be thermally sprayed directly onto the E-pack 100, by way of example.

[0043] The heater 140 is disposed between the dielectric layer 135 and the cold plate 160. In at least one embodiment of the present disclosure, the heater 140 includes a heating layer 142, an interlayer dielectric 145, and a routing layer 146. The interlayer dielectric 145 is disposed between the heating layer 142 and the routing layer 146. The heating layer 142 includes a heating layer substrate 143, which in one embodiment of the present disclosure is a thin layer (approximately 0.001 inches to 0.002 inches) of elastomer. The heating layer substrate 143 functions to affix the at least one heating element 144 to the dielectric layer 135. The routing layer 146 includes a routing layer substrate 147, which is a material that has the dual function of adding dielectric strength while adhering the routing layer 146 to the cold plate 160. As shown, the routing layer 146 includes at least one routing element 148. At least one via interconnect 149 is disposed between the heating layer 142 and the routing layer 146. Thus, at least one heating element 144 is electrically connected to at least one routing element 148. This allows for the presence of multiple heating zones, as illustrated. More details are provided below. FIG. 1B illustrates the heater 140 having an upper (+z direction) heating layer 142 and a lower (-z direction) routing layer 146. However, the heating layer 142 and the routing layer 146 may be in any order, provided that the diffuser layer 120 is disposed directly on the E-pack 100. For example, the heating layer 142 may be disposed below the interlayer dielectric 145 (-z direction) and the wiring layer 146 may be disposed above the interlayer dielectric 145 (+z direction). Other functional layers, such as sensor layers, may also be provided in addition to those shown and described.

[0044] In one form, the cooling plate 160 includes cooling channels 162 through which a cooling fluid flows to allow heat from the heater 140 and other components or targets associated with the E-chuck 10 to be conducted away from the E-pack 100 during semiconductor processing of one or more wafers.

[0045] 1B shows only one bonding layer, namely bonding layer 130, it is understood that one or more bonding layers can be included and disposed between various layers of E-pack 10. For example, a bonding layer (not shown) can be disposed between heater 140 and cold plate 160.

[0046] 2A-2G illustrate a method of manufacturing an E-chuck 10 according to the teachings of the present disclosure. The method includes manufacturing an E-pack 100 having at least one electrode 104 embedded in a substrate 102, as shown in FIG. 2A. The method includes forming a diffusion layer 120 on a first surface 106, as shown in FIG. 2B. The diffusion layer 120 includes a first surface 122, a second surface 124, and a thickness (z-direction, not shown) between the first surface 122 and the second surface 124. In at least one variation of the present disclosure, the first surface 122 of the diffusion layer 120 is disposed directly on the first surface 106 of the E-pack 100. In other variations, the first surface 122 of the diffusion layer 120 is not disposed directly on the first surface 106 of the E-pack 100. For example, one or more additional layers (not shown) are disposed between the first surface 122 of the diffusion layer 120 and the first surface 106 of the E-pack 100. The diffusion layer 120 can be deposited using any known or yet to be developed material layer deposition technique(s). Non-limiting examples of material layer deposition techniques include cathodic arc discharge, cold spray, chemical vapor deposition (CVD) techniques, physical vapor deposition (PVD) techniques, sol-gel techniques, sputtering, and vacuum plasma spray. In one aspect of the present disclosure, a cold spray apparatus "S" is used to deposit aluminum on the first surface 106 of the E-pack 100.

[0047] The diffusion layer 120 is formed from a material having a high thermal conductivity. As used herein, "high thermal conductivity" means a thermal conductivity of greater than 10 W / mK, such as greater than 50 W / mK, or greater than 100 W / mK. Non-limiting examples of materials used to form the diffusion layer 120 include aluminum, copper, silver, gold, nickel, and alloys thereof. Other non-limiting examples of materials used to form the diffusion layer 120 include diamond-like carbon (DLC) and AlN, among others. Additionally, the diffusion layer 120 has a thickness between about 0.005 inches (0.13 mm) and about 0.100 inches (2.54 mm). For example, in one variation, the diffusion layer 120 has a thickness between about 0.010 inches (0.25 mm) and about 0.020 inches (0.51 mm). In another variation, the diffusion layer 120 has a thickness between about 0.020 inches (0.51 mm) and about 0.030 inches (0.76 mm). In yet another variation, the diffusion layer 120 has a thickness between about 0.030 inches (0.76 mm) and about 0.040 inches (1.02 mm).

[0048] The diffusion layer 120 may have a monolithic composition along its thickness (z-direction) or may have a graded composition (or coefficient of thermal expansion (CTE) variation) across its thickness (z-direction) to reduce the thermal expansion mismatch between the first surface 122 of the diffusion layer 120 and the first surface 106 of the E-pack 100. In one variation, the diffusion layer 120 has a first thickness (unlabeled) adjacent the first surface 106 of the substrate 102 and a second thickness (unlabeled) distal (further away) from the first surface 106 compared to the first thickness. The first thickness has a first composition and the second thickness has a second composition that is different from the first composition. Also, the first composition has a first coefficient of thermal expansion (CTE) and the second composition has a second CTE that is different from the first CTE. One non-limiting example includes a substrate 102 formed from alumina and a diffusion layer 120 having a first thickness (unlabeled) having a first composition extending from the first surface 106 to the second surface 108, and a second thickness (unlabeled) having a second composition extending from the first thickness to the second surface 108. The first thickness is about 10-15 μm, and the first composition has a CTE of about 1.1 times that of alumina. The second thickness is about 25-50 μm, and the second composition has a CTE of about 1.2 times that of alumina. Additional thicknesses having different compositions (and different CTEs) can be included in the diffusion layer 120 such that the diffusion layer has a gradient of CTE values. Alternatively, the entire diffusion layer 120 can have a composition that varies continuously from the first surface 122 to the second surface 124. This results in the diffusion layer 120 having a gradient CTE from the first surface 122 to the second surface 124.

[0049] 2C, at least one groove 126 (also referred to herein as a "gap") is formed in the diffusion layer 120. The groove 126 extends from the second surface 124 of the diffusion layer 120 toward the first surface 106 of the E-pack 100. In some variations of the present disclosure, the one or more grooves 126 extend completely through the diffusion layer 120, i.e., from the second surface 126 of the diffusion layer 120 to the first surface 106 of the E-pack 100. In other variations, the one or more grooves 126 extend only partially through the diffusion layer 120. In still other variations, the one or more grooves 126 have at least one portion (not shown) where the groove 126 extends completely through the diffusion layer 120 and at least one other portion where the groove 126 extends only partially through the diffusion layer 120. In one aspect of the present disclosure, the at least one groove is formed using a laser "L", e.g., by laser machining.

[0050] It should be understood that the at least one groove 126, and other grooves disclosed herein, can be formed using any known or yet to be developed material removal technique. Non-limiting examples of material removal techniques include grinding, laser cutting, etching, machining, photolithography, and sand or grit blasting, among others. Also, Figures 2B and 2C show a diffusion layer having at least one groove 126 by depositing the diffusion layer 120 and then removing material to form the groove 126. However, other techniques or methods can be used to form the diffusion layer 120 and the groove 126. For example, in one variation, the first surface 106 is masked (not shown) to cover the location or location of the groove 126, the diffusion layer 120 is deposited on the first surface 106, and then the mask is removed to expose the groove 126 in the diffusion layer 120. Alternatively, or in addition, the diffusion layer 120 having the grooves 126 is formed using additive manufacturing techniques (eg, 3D printing) without a masking or subsequent removal step as described herein.

[0051] 2D and 2E, the method includes forming a plurality of grooves 126 such that discrete diffusion segments 128 are formed and separated by the grooves 126, and machining the diffusion layer 120 (FIG. 2E) to provide a generally flat second surface 124 that is generally parallel to the second surface 108 of the E-pack 100. That is, the second surface 126 is machined to provide a flat diffusion layer 120 at the interface where the heater 140 is to be secured. Non-limiting examples of machining techniques or processes for machining the diffusion layer include lapping, polishing, and chemical mechanical polishing (CMP), among others. FIG. 2E illustrates machining of the diffusion layer 120 after at least one groove 126 is formed. However, the diffusion layer 120 may be machined before the at least one groove 126 is formed or during the same process as the formation of the grooves.

[0052] 2F shows the completed diffusion layer 120, which has a central or first discrete diffusion segment 128a separated from a second discrete diffusion segment 128b by grooves 126a, a third discrete diffusion segment 128c separated from the second discrete diffusion segment 128b by grooves 126b, and a fourth discrete diffusion segment 128d separated from the third discrete diffusion segment 128c by grooves 126c.

[0053] 2G, the method includes assembling an E-pack 100 with a diffusion layer 120, a dielectric layer 135, a heater 140, and a cooling plate 160 to obtain the E-chuck 10 shown in FIG. 1B. In particular, the E-pack 100 with the diffusion layer 120 is bonded to the dielectric layer 135, which is bonded to the heater 140, which is bonded to the cooling plate 160. In at least one variation of the present disclosure, a bonding layer 130 is disposed between the diffusion layer 120 and the heater 140. Additional bonding layers may also be disposed between various layers of the E-chuck 10. At least one groove 126 may be filled with air, an elastomeric material, a dielectric material, and / or a bonding material, which provides a low thermal conductivity gap between adjacent discrete diffusion segments 128.

[0054] The dielectric layer 135 electrically insulates the heater 140 from the diffusion layer 120. Non-limiting examples of materials used to form the dielectric layer 135 include elastomers, polyimides, thermally sprayed dielectrics (e.g., Al2O3, yttria), thick film dielectrics, liquid polyimides, and other dielectric polymers. The heater 140 can be any heater known or yet to be developed for use with an E-chuck to provide heat to the E-chuck. Non-limiting examples of the heater 140 include a polyimide foil heater, a layered heater, or a damascene heater, among others. In at least one embodiment of the present disclosure, the heater 140 includes an interlayer dielectric 145 disposed between an elastomeric heating layer substrate 143 and an elastomeric wiring layer substrate 147.

[0055] 3A-3D show non-limiting examples of grooves 126 formed in the diffusion layer 120. For example, FIG. 3A shows a rectangular groove 126 extending from the second surface 124 of the diffusion layer 120 to the first surface 106 of the E-pack 100. That is, the rectangular groove 126 of FIG. 3A extends completely through the diffusion layer 120. This results in discrete diffusion segments 128L and 128R being separated by the groove. Alternatively, FIG. 3B shows a rectangular groove 126 extending from the second surface 124 of the diffusion layer 120 toward, but not completely through, the first surface 106 of the E-pack 100. That is, FIG. 3B shows the rectangular groove 126 of FIG. 3A extending only partially through the diffusion layer 120. This results in discrete diffusion segments 128L and 128R being separated by the groove. 3C shows a hemispherical shaped groove 126 extending into the diffusion layer 120, and FIG. 3D shows a V shaped groove 126 extending into the diffusion layer 120, such that discrete diffusion segments 128L and 128R are separated by the groove. The groove 126 may have other shapes, which extend completely or partially through the diffusion layer 120, such that discrete diffusion segments are separated by the groove.

[0056] FIG. 2E illustrates the diffusion layer 120 having radially arranged discrete diffusion segments 128a-128d. However, the diffusion layer 120 may also include azimuthally arranged discrete diffusion segments. For example, referring to FIG. 4, the diffusion layer 120 includes a central discrete diffusion segment 128a separated from a first radially arranged discrete diffusion segment 128b by a groove 126a, and a plurality of second radially arranged discrete diffusion segments 128c separated from the first radially arranged discrete diffusion segment 128b by a groove 126b and azimuthally separated from each other by a groove 127a. As shown in FIG. 4, in one variation, the plurality of second radially arranged discrete diffusion segments 128c includes four second radially arranged discrete diffusion segments 128c. However, the number of second radially arranged discrete diffusion segments 128c may be less than four or more than four. Additionally, the plurality of third radial discrete diffusion segments 128d are separated from the second radial discrete diffusion segments 128c by grooves 126c and azimuthally separated from each other by grooves 127b. As shown in FIG. 4, in one variation, the plurality of third radial discrete diffusion segments 128d includes four third radial discrete diffusion segments 128d. However, the number of third radial discrete diffusion segments 128d may be less than four or more than four. In addition, the diffusion layer 120 may include any number of radial discrete diffusion segments and any number of azimuth discrete diffusion segments. For example, the diffusion layer 120 shown in FIG. 5 includes a central discrete diffusion segment 128, nine radial discrete diffusion segments 128 separated by grooves 126, and up to 24 azimuth discrete diffusion segments 128 within a given radial discrete diffusion segment separated by grooves 127. Furthermore, adjacent radially discrete diffusion segments can be aligned, as shown in FIG. 4, or offset from one another, as shown in FIG.

[0057] 2E, 4, and 5 show the diffusion layer 120 having regularly shaped discrete diffusion segments 128 having a generally constant radial width and / or azimuthal length. However, in some variations of the present disclosure, the diffusion layer 120 may include irregularly shaped discrete diffusion segments. For example, FIG. 6 shows a diffusion layer 120 having a plurality of irregularly shaped discrete diffusion segments 128' separated by grooves or channels 126'.

[0058] 7, there is shown the results of a Finite Element Analysis (FEA) of the temperature at the outer surface (e.g., second surface 108) of the substrate and the temperature range at the outer surface as a function of the thickness of the diffusion layer (+z direction in FIG. 1). In particular, an FEA of an alumina substrate heated to an average temperature of about 79° C. was performed with no diffusion layer, a 0.010 inch thick diffusion layer, a 0.020 inch thick diffusion layer, and a 0.030 inch thick diffusion layer. The maximum temperature, minimum temperature, and temperature range (i.e., maximum temperature minus minimum temperature) were determined from the FEA and are plotted in FIG. 7. As shown in FIG. 7, with a 0.030 inch thick diffusion layer, the temperature range at the outer surface is reduced from about 7.6° C. to about 4.8° C., or approximately 40%.

[0059] Thus, each discrete diffusion segment enhances temperature uniformity in a particular region or area of ​​the E-pack outer surface. Meanwhile, the grooves at least partially thermally decouple the discrete diffusion segments from one another. This allows a desired thermal gradient (e.g., 20° C. from the center to the edge of the discrete diffusion segment 128) to be maintained between the segments during heating of a target on the E-pack. The term "at least partially thermally decoupled" (and variations thereof) should be interpreted to mean that the thermal conductivity of the grooves / gaps 26 / 126 between the diffusion segments 28 / 128 is less than or independent of the thermal conductivity of the adjacent diffusion segments 128. For example, the grooves / gaps 26 / 126 may have a thermal conductivity of about 50% or less of the diffusion segments 28 / 128 while remaining within the scope of the present disclosure.

[0060] Additionally, while the diffusion segments 28 / 128 are illustrated herein as having an arcuate geometry, they may be any shape or combination of shapes, whether the same or different, in a given diffusion layer 20 / 120 while remaining within the scope of the present disclosure in order to provide a desired thermal gradient across the E-pack 10 / 100.

[0061] As shown and discussed above, an E-chuck with a diffusion layer can enhance temperature uniformity across the surface of the E-pack, thereby enhancing temperature uniformity of a target on the E-pack. The diffusion layer also has discrete diffusion segments that are thermally decoupled from one another, for example, by grooves or gaps provided between the discrete diffusion segments. This maintains a desired thermal gradient between the segments during heating of a target on the E-pack. The combination of enhanced E-pack surface temperature uniformity and thermal gradient control between regions or across portions of the E-pack surface enhances process control during semiconductor wafer processing.

[0062] When an element or layer is referred to as being "on," "engaged to," or "disposed on" another element or layer, it may be directly engaged, connected, or disposed on the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly disposed on" another element or layer, there may not be intervening elements or layers. Other words used to describe relationships between elements should be interpreted similarly (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0063] Terms such as first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may only be used to distinguish one element, component, region, layer, and / or section from another element, component, region, layer, and / or section. As used herein, terms such as "first", "second", and other numerical terms do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer, or section can be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments. Furthermore, an element, component, region, layer, or section can be referred to as a "second" element, component, region, layer, or section without the element, component, region, layer, or section being referred to as a "first" element, component, region, layer, or section.

[0064] Spatially relative terms such as "inner," "outer," "beneath," "below," "lower," "above," "upper," and the like may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) as shown in the figures. The spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, an element described as "below" or "beneath" the other element or feature would then be oriented "above" the other element or feature. Thus, the exemplary term "below" can encompass both an above or below orientation. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein would be interpreted accordingly.

[0065] As used herein, the phrase at least one of A, B, and C should be construed to mean a non-exclusive logical OR (A OR B OR C), and not to mean "at least one of A, at least one of B, and at least one of C."

[0066] Unless expressly indicated otherwise, all numerical values ​​expressing mechanical / thermal properties, compositional percentages, dimensions and / or tolerances, or other characteristics are to be understood as being modified by the word "about" or "approximately" in describing the scope of this disclosure. This modification may be desirable for a variety of reasons, including industrial practices, manufacturing techniques, and testing capabilities.

[0067] The terms used herein are for the purpose of describing particular exemplary embodiments only and are not intended to be limiting. The singular forms "a," "an," and "the" may be intended to include the plural unless the context clearly indicates otherwise. The terms "including" and "having" are inclusive and thus specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring their execution in the particular order discussed or illustrated, unless specifically identified as an order of execution. It is also understood that additional or alternative steps may be employed.

[0068] The description of the present disclosure is merely exemplary in nature, and therefore examples that do not depart from the essence of the present disclosure are intended to be within the scope of the present disclosure. Such examples should not be considered as departing from the spirit and scope of the present disclosure. The broad teachings of the present disclosure can be implemented in various forms. Thus, although the present disclosure includes specific embodiments, other modifications will become apparent upon review of the drawings, specification, and claims that follow, and therefore the true scope of the present disclosure should not be so limited.

[0069] The invention as originally claimed in the present application is set forth below. (1) Depositing a diffusion layer on the electrostatic pack; removing regions of the diffusion layer to form discrete diffusion segments separated by gaps; coupling the electrostatic pack to a heater, and disposing the diffusion layer between the electrostatic pack and the heater; An electrostatic chuck is formed by adhering the heater to a cooling plate. (2) 2. The electrostatic chuck of claim 1, wherein the discrete diffusion segments are at least one of continuous concentric circles, discontinuous concentric circles, and a combination of continuous and discontinuous concentric circles. (3) 2. The electrostatic chuck of claim 1, wherein the discrete diffusion segments are separated by forming at least one groove in the diffusion layer. (4) 4. The electrostatic chuck of claim 3, wherein the at least one groove extends partially through the diffusion layer, completely through the diffusion layer to the electrostatic puck, or partially through the diffusion layer and completely through the diffusion layer to the electrostatic puck to define a variable depth. (5) 4. The electrostatic chuck of claim 3, wherein the at least one groove defines a variable width. (6) 4. The electrostatic chuck of claim 3, wherein the at least one groove is formed by one of acid etching, laser cutting, and machining. (7) 2. The electrostatic chuck of claim 1, wherein the electrostatic puck is a ceramic material. (8) the heater has at least two heating zones; 10. The electrostatic chuck of claim 1, wherein the discrete diffusion segments are axially aligned with the at least two heating zones, thereby thermally decoupling the at least two heating zones from one another. (9) the heater having an outer heating zone and an inner heating zone; 2. The electrostatic chuck of claim 1, wherein the discrete diffusion segments are axially aligned with the outer heating zone and the inner heating zone to thermally decouple the outer heating zone from the inner heating zone, thereby maintaining a desired thermal gradient between the outer heating zone and the inner heating zone during heating of a target on the electrostatic puck. (10) The electrostatic chuck of (1), wherein the diffusion layer is formed from one of the following materials: aluminum, molybdenum, tungsten, nickel, zinc, silicon, and alloys thereof. (11) 13. The electrostatic chuck of claim 1, wherein the diffusion layer is at least one of: cold spraying aluminum directly onto the electrostatic puck; and an aluminum diffusion layer having a thickness of less than 0.040 inches (1.02 mm). (12) 2. The electrostatic chuck of claim 1, wherein the heater is one of a foil heater, a layered heater, or a damascene heater. (13) The electrostatic chuck according to (1), wherein the heater is a polyimide heater. (14) 14. The electrostatic chuck of claim 13, wherein the electrostatic puck is bonded to the polyimide heater with an elastomer. (15) 14. The electrostatic chuck of claim 13, further comprising a base plate, the polyimide heater being bonded to the base plate with an elastomer.

Claims

1. Electrostatic pack, a diffusion layer deposited on the electrostatic pack; the diffusion layer defining discrete diffusion segments; a heater provided on the diffusion layer; a cooling plate bonded to the heater; Equipped with the diffusion layer is disposed between the electrostatic pack and the heater; the discrete diffusion segments being formed of the same material and configured to maintain a desired thermal gradient between the discrete diffusion segments during heating of a target on the electrostatic puck; the discrete diffusion segments are formed by a diffusion layer formed from material formed directly on the electrostatic puck and at least one groove formed by removing a portion of the diffusion layer; the portions of the diffusion layer that are not removed form the discrete diffusion segments separated by the at least one groove.

2. 2. The electrostatic chuck of claim 1, wherein the discrete diffusion segments are at least one of continuous concentric circles, discontinuous concentric circles, and a combination of continuous and discontinuous concentric circles.

3. 2. The electrostatic chuck of claim 1, wherein the at least one groove extends partially through the diffusion layer, completely through the diffusion layer to the electrostatic puck, or partially through the diffusion layer and completely through the diffusion layer to the electrostatic puck to define a variable depth.

4. The electrostatic chuck of claim 1 , wherein the at least one groove defines a variable width.

5. 10. The electrostatic chuck of claim 1, wherein the at least one groove is formed by one of acid etching, laser cutting, and machining.

6. 10. The electrostatic chuck of claim 1, wherein the electrostatic puck is a ceramic material.

7. The heater has at least two heating zones; 2. The electrostatic chuck of claim 1, wherein the discrete diffusion segments are axially aligned with the at least two heating zones, thereby thermally decoupling the at least two heating zones from one another.

8. the heater having an outer heating zone and an inner heating zone; 2. The electrostatic chuck of claim 1, wherein the discrete diffusion segments are axially aligned with the outer heating zone and the inner heating zone to thermally decouple the outer heating zone from the inner heating zone, thereby maintaining the desired thermal gradient between the outer heating zone and the inner heating zone during the heating of the target on the electrostatic puck.

9. 10. The electrostatic chuck of claim 1, wherein the diffusion layer is formed from one of the following materials: aluminum, molybdenum, tungsten, nickel, zinc, silicon, and alloys thereof.

10. 10. The electrostatic chuck of claim 1, wherein the diffusion layer is at least one of: cold sprayed aluminum directly onto the electrostatic puck; and an aluminum diffusion layer less than 0.040 inches (1.02 mm) thick.

11. 10. The electrostatic chuck of claim 1, wherein the heater is one of a foil heater, a layered heater, or a damascene heater.

12. 10. The electrostatic chuck of claim 1, wherein the heater is a polyimide heater.

13. 13. The electrostatic chuck of claim 12, wherein the electrostatic puck is elastomerically bonded to the polyimide heater.

14. 13. The electrostatic chuck of claim 12, further comprising a base plate, said polyimide heater being elastomerically bonded to said base plate.

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