Electrical termination for ceramic pedestal with embedded electrical components

Abstract

An electrical termination assembly includes a ceramic insert defining a plurality of bores and a plurality of liners disposed within each of the plurality of bores. Each liner has a blind bore and a distal end face, the distal end face being exposed through the respective bore of the ceramic insert. A plurality of termination pins are secured within each of the blind bores of the plurality of liners, and the plurality of liners are made of a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert and a CTE of the termination pins.

Description

ELECTRICAL TERMINATION FOR CERAMIC PEDESTAL WITH EMBEDDEDELECTRICAL COMPONENTSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. provisional application number 63 / 622,275 filed January 18, 2024. The disclosure of the above application is incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure relates to electrical terminations, and more specifically to electrical terminations to components embedded within ceramic substrates, such as by way of example a radio frequency (RF) antenna embedded within a ceramic pedestal for semiconductor processing.BACKGROUND

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

[0004] Ceramic pedestals for use in semiconductor processing typically include a number of embedded electrical components, such as by way of example, a clamping electrode, an RF antenna, and heater circuits, among others. Because ceramic materials are inherently brittle and have relatively low coefficients of thermal expansion, embedding electrically conductive terminations having higher coefficients of thermal expansion is challenging and can lead to cracking of the ceramic materials. More specifically, it is difficult to connect metal electrodes to the embedded electrical components because the electrical components are made from refractory metals or conductive ceramics which have very low coefficients of thermal expansion.

[0005] The electrical components are generally formed in layers and are typically thin and are surrounded by the ceramic material. Bonding metal electrodes, which are typically nickel or nickel alloys, directly to the thin electrical component, usually by brazing, may result in stress and damage to the ceramic in that area and / or an adjacent electrically conductive layer if coefficients of thermal expansion of the different materials are not accounted for. Additionally, any embedded electrical component must be sealed from the atmosphere surrounding the ceramic pedestal, i.e., within the semiconductor processing chamber. However, embedded electricalcomponents suffer from poor oxidation resistance at elevated temperatures, which limits their life and / or reduces reliability.

[0006] The present disclosure addresses these issues, among other integration issues, related to electrical terminations within ceramic substrates / pedestals.SUMMARY

[0007] This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.

[0008] In one form of the present disclosure, an electrical termination assembly comprises a ceramic insert defining a plurality of bores, a plurality of liners disposed within each of the plurality of bores, each liner comprising a blind bore and a distal end face, the distal end face being exposed through the respective bore of the ceramic insert, and a plurality of termination pins secured within each of the blind bores of the plurality of liners. The plurality of liners comprise a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert and a CTE of the termination pins.

[0009] In variations of this electrical termination assembly, which may be implemented individually or in any combination: the ceramic insert is an aluminum nitride (AIN) material, and the plurality of liners comprise a composite material having Molybdenum (Mo) and Tungsten (W); the ceramic insert comprises a lower flanged portion; the ceramic insert comprises an upper flanged portion; a plurality of bond layers are disposed between the plurality of termination pins and the plurality of liners; the bond layer is selected from the group consisting of a braze layer, a solid state bond layer, and a transient liquid phase bond layer; and a sheath is disposed around a proximal end portion of the termination pins.

[0010] In another form, a ceramic assembly comprises a ceramic body comprising at least one recess, at least one electrical component embedded within the ceramic body, and an electrical termination assembly disposed within the recess. The electrical termination assembly comprises a ceramic insert disposed within the ceramic body, the ceramic insert defining a plurality of bores, a plurality of liners disposed within each of the plurality of bores, each liner comprising a blind bore and a distal end face, the distal end face being exposed through the respective bore of the ceramic insert, and a plurality of termination pins secured within each of the blind boresof the plurality of liners. The plurality of liners comprise a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert and a CTE of the termination pins.

[0011] In variations of this ceramic assembly, which may be implemented individually or in any combination: the electrical termination assembly is bonded to the ceramic body; a bond layer is disposed between the distal end face of the plurality of liners and the electrical component; the bond layer is selected from the group consisting of a braze layer, a solid state bond layer, and a transient liquid phase bond layer; a sealing layer is disposed between an exterior surface of the ceramic insert and the ceramic body; the ceramic insert comprises a lower flanged portion; the sealing layer is disposed between the exterior surface of the ceramic insert and an upper surface of the lower flanged portion; the sealing layer comprises a glass material; the ceramic insert comprises an upper flanged portion; and a sheath is disposed around a proximal end portion of the termination pins.

[0012] In yet another form of the present disclosure, a ceramic pedestal assembly comprises a ceramic pedestal comprising at least one recess, a radio frequency (RF) antenna embedded within the ceramic pedestal, and an electrical termination assembly disposed within the recess. The electrical termination assembly comprises a ceramic insert disposed within the ceramic pedestal, the ceramic insert defining a plurality of bores, a plurality of liners disposed within each of the plurality of bores, each liner comprising a blind bore and a distal end face, the distal end face being exposed through the respective bore of the ceramic insert, and a plurality of termination pins secured within each of the blind bores of the plurality of liners. The plurality of liners comprise a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert and a CTE of the termination pins, and a bond layer is disposed between the distal end face of the plurality of liners and the RF antenna.

[0013] In variations of this ceramic pedestal assembly, which may be implemented individually or in any combination: a resistive heater is embedded within the ceramic pedestal; and a sheath is disposed around a proximal end portion of the termination pins.

[0014] In still another form of the present disclosure, an electrical termination assembly comprises a ceramic insert defining a plurality of bores, a plurality of liners disposed within each of the plurality of bores, each liner comprisinga blind bore and a distal end face, the distal end face being exposed through the respective bore of the ceramic insert, a plurality of termination pins secured within each of the blind bores of the plurality of liners, an intermediate conductive layer in electrical contact with the plurality of liners, and at least one conductive via in electrical contact with the intermediate conductive layer and extending through an upper surface of the ceramic insert The plurality of liners comprise a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert and a CTE of the termination pins.

[0015] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.DRAWINGS

[0016] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0017] FIG. 1 is a side schematic view of a ceramic assembly having embedded electrical components and terminations according to the teachings of the present disclosure;

[0018] FIG. 2 is a side cross-sectional view within detail 2-2 of FIG. 1 , of an electrical termination assembly according to the teachings of the present disclosure;

[0019] FIG. 3A is a perspective view of the electrical termination assembly of FIG. 2;

[0020] FIG. 3B is an exploded view of the electrical termination assembly of FIG. 2;

[0021] FIG. 4A is a perspective view of one form of an electrical termination assembly constructed according to the teachings of the present disclosure;

[0022] FIG. 4B is another perspective view of the electrical termination assembly of FIG. 4A;

[0023] FIG. 4C is a bottom view of the electrical termination assembly of FIG. 4A;

[0024] FIG. 5 is another perspective view of the electrical termination assembly of FIG. 4A;

[0025] FIG. 6A is a side view of an electrical termination assembly having a protective sheath secured around termination pins and constructed according to the teachings of the present disclosure;

[0026] FIG. 6B is a bottom perspective view of the electrical termination assembly of FIG. 6A;

[0027] FIG. 7 is a perspective view of a ceramic assembly constructed according to the teachings of the present disclosure;

[0028] FIG. 8 is a side cross-sectional view of another electrical termination assembly constructed according to the teachings of the present disclosure; and

[0029] FIG. 9 is a side cross-sectional view of another electrical termination assembly constructed according to the teachings of the present disclosure.

[0030] 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

[0031] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0032] Referring to FIGS. 1 - 2, a ceramic pedestal assembly according to the teachings of the present disclosure is illustrated and generally indicated by reference numeral 20. The ceramic pedestal assembly 20 in this form comprises a ceramic pedestal 22 that includes a ceramic body, which in this form is a plate member 24, and a shaft 26 secured to the plate member 24. The plate member 24 comprises a ceramic material, such as by way of example, aluminum nitride (AIN) or beryllium oxide (BeO), among others. Similarly, the shaft 26 also comprises a ceramic material in one form of the present disclosure. Further details of the materials and constructionof exemplary ceramic pedestals are disclosed in pending U.S. applications 63 / 341 ,163 titled "HYBRID SHAFT ASSEMBLY FOR THERMAL CONTROL IN HEATED SEMICONDUCTOR PEDESTALS" and 63 / 310,448 titled " SOLID-STATE BONDING METHOD FOR THE MANUFACTURE OF SEMICONDUCTOR CHUCKS AND HEATERS," which are commonly owned with the present application and the contents of which are incorporated herein by reference in their entirety.

[0033] As further shown, a radio frequency (RF) antenna 28 is embedded within the ceramic pedestal 22, and more specifically within the plate member 24. In this form, a resistive heater 30 is also embedded within the ceramic pedestal 22 (and more specifically the plate member 24). It should be understood that a variety of electrical components other than the RF antenna 28 and / or the resistive heater 30 may be embedded within or operatively engaged with the ceramic pedestal assembly 20 while remaining within the scope of the present disclosure. The ceramic pedestal assembly 20 further comprises at least one recess 32 (FIG. 2), and an innovative electrical termination assembly 40 disposed within the recess 32, which is now described in greater detail.

[0034] Referring to FIGS. 3A and 3B, along with FIG. 2, the electrical termination assembly 40 comprises a ceramic insert 42 generally disposed within, or at least partially embedded within the plate member 24 of the ceramic pedestal 22. More specifically, the ceramic insert 42 is disposed within the recess 32 as shown. The ceramic insert 42 includes a plurality of bores 44 extending through an entire length of the ceramic insert 42 as shown. A plurality of corresponding liners 46 are disposed within each of the bores 44, and each liner 46 has a blind bore 48. A distal end face 49 of each liner 46 is exposed through the respective bore 44 of the ceramic insert 42, and the distal end face 49 is configured to be in electrical communication with the RF antenna 28, or other electrical component (e.g., resistive heater 30) embedded within the plate member 24.

[0035] A corresponding plurality of termination pins 50 are secured within each of the blind bores 48 of the liners 46, which is described in greater detail below. In order to reduce the deleterious effects (i.e., cracking of the plate member 42) of thermal expansion during manufacture and operation, the liners 46 comprise a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert 42 and a CTE of the termination pins 50. In one form, the ceramic insert 42 is an aluminum nitride (AIN) material, and the liners 46 are a compositematerial having Molybdenum (Mo) and Tungsten (W). In one form, the ratio, by volume fraction, of Mo to W is between about 20% to about 95%. In this variation, the termination pins 50 comprise a nickel-cobalt ferrous alloy, such as the Kovar® brand alloy. It should be understood that a variety of different materials for each of the liners 46, ceramic insert 42, and termination pins 50 may be employed as long as the CTE of the ceramic insert 42 is between that of the liners 46 and the termination pins 50, while remaining within the scope of the present disclosure. For example, the liners 46 may include other materials such as, by way of example, TiN (titanium nitride), TiC (titanium carbine), WC (tungsten carbide), B4C (boron carbide), or tantalum, among others, while remaining within the scope of the present disclosure.

[0036] The termination pins 50 are secured within the liners 46 via a bond layer 52, which surrounds the termination pin 50 as shown. The bond layer 52 may be a braze layer (brazing), a solid state bond layer (solid-state / diffusion bonding), or a transient liquid phase (TLP) bond layer (TLP bonding). Further, the bond layer 52 may be any of a variety of materials, such as by way of example, a titanium rich braze alloy such as BTi-5, among others. It should be understood that a variety of materials can be used for the bond layer 52, provided the material has a CTE close to that of the termination pin 50 and the liner 46. And while a plurality of termination pins 50 and corresponding blind bores 48 are illustrated and described, it should be understood that the teachings of the present disclosure may be applied to an electrical termination assembly 40 that includes only a single termination pin 50 within a single blind bore 48 while remaining within the scope of the present disclosure. (See FIGS. 8 and 9 for an exemplary single termination pin variation, which is not limited to the specific design of the ceramic insert as shown).

[0037] As further shown, another bond layer 60 is disposed between the distal end face 49 of each liner 46 and the RF antenna 28, as well as between an upper end 43 of the ceramic insert 42 and the RF antenna 28. This bond layer 60 may be any of a variety of materials that has a CTE substantially equal to or between that of the liner 46 and the plate member 24. The bond layer 60 is generally a material such as the materials set forth above relative to the bond layer 52, such as titanium rich braze alloys. Further the distal end face 49 of the liner 46 and the upper end 43 of the ceramic insert 42 may be secured to the RF antenna 28, via the bond layer 60, with brazing, solid-state / diffusion bonding, or transient liquid phase (TLP) bonding.

[0038] The ceramic insert 42 in this form comprises a lower flanged portion 70. The lower flanged portion 70 includes an upper face 72 and a lower face 74. The upper face 72 is configured to abut an exterior surface 25 of the plate member 24 and thus locate the ceramic insert 42 within the recess 32. In certain applications, such as by way of example the ceramic pedestal assembly 20 for semiconductor processing, the interface between the ceramic insert 42 and the plate member 24 is hermetically sealed. As such, in this form, a sealing layer 76 is disposed between the upper face 72 of the ceramic insert 42 and the exterior surface 25 of the plate member 24. The sealing layer 76 in one form is a glass material. It should be understood, however, that a variety of materials for the sealing layer 76 may be used while remaining within the scope of the present disclosure.

[0039] Referring now to FIGS. 4A - 4C and 5, an exemplary electrical termination 40 assembly is illustrated in greater detail. In this form, a total of five (5) liners 46 and termination pins 50 are secured within the ceramic insert 42. The flanged portion 70 is illustrated with the upper face 72 and the lower face 74, along with the distal end face 49 of the liner 46.

[0040] Turning to FIGS. 6A and 6B, the electrical termination assembly 40 in one form includes a sheath 80 disposed around a proximal end portion 51 of the termination pins 50. The sheath 80 in one form is brazed to the termination pins 50, however, other forms of securing or bonding may be employed while remaining within the scope of the present disclosure. The sheath 80 further includes an electrical connection portion 82, which is adapted to receive power leads 84 to supply power to the electrical termination assembly 40. Although not shown, both the termination pins 50 and the sheath 80 extend through the shaft 26 (FIG. 1 ) when the application for the electrical termination assembly 40 is a ceramic pedestal assembly 20.

[0041] Referring to FIG. 7, an exemplary ceramic assembly is illustrated and generally indicated by reference numeral 90. The ceramic assembly 90 includes at least one ceramic body 92 comprising at least one recess 94 (three (3) recesses 94 are used in this assembly). The ceramic assembly 90 includes at least one electrical component (e.g., RF antenna 28, resistive heater 30) embedded therein (not shown), as previously illustrated and described. The electrical termination assembly 40 set forth above is disposed within each of the recesses 94 as shown, and more specifically is bonded to the ceramic body 92 as described herein. Two electrical termination assemblies 40 on the outer periphery of the ceramic body 92 include the ceramic insert42 with the flanged portion 70 as previously set forth, and the center electrical termination assembly 40' includes a ceramic insert 42' without the flanged portion. The ceramic insert 42' in this form is generally in the shape of a cylindrical plug and is recessed inside the ceramic body 92 as shown. Accordingly, a variety of shapes, sizes, and installation configurations for the electrical termination assemblies 40 / 40' are contemplated by the teachings of the present disclosure.

[0042] Referring now to FIG. 8, another form of an electrical termination assembly is illustrated and generally indicated by reference numeral 100. Similar elements and features, and their variations and materials as set forth above are not repeated here for purposes of clarity. As shown, a ceramic insert 102 in this form comprises an upper flanged portion 104 (versus the lower flanged portion 70 illustrated and described above). A bond layer 110 is disposed between an upper surface of the upper flanged portion and the electrical component, such as the RF antenna 28, and also between the distal end face 49 of the liner 48 and the RF antenna 28. The bond layer 110 is similar to the bond layer 60 as set forth above. A sealing layer 112 (similar to the sealing layer 76 as set forth above) is disposed between the upper flanged portion 104 of the ceramic insert 102 and a surface of the plate member 24. The sealing layer 112 in one form is a glass material. It should be understood, however, that a variety of materials for the sealing layer 112 may be used while remaining within the scope of the present disclosure. And although only one termination pin 50 is shown, it should be understood that any number of termination pins 50 can be employed within a single ceramic insert 102 while remaining within the scope of the present disclosure.

[0043] Referring to FIG. 9, yet another form of an electrical termination assembly is illustrated and generally indicated by reference numeral 200. In this form, the electrical termination assembly 200 includes a ceramic insert 202 with two sets of termination pins 50, liners 46, and bond layers 52. However, it should be understood that only one set, or more than two sets may be employed while remaining within the scope of the present disclosure. Rather than the liners 46 directly contacting the RF antenna 28 as previously illustrated and described, the electrical termination assembly 200 in this form includes an intermediate conductive layer 204 and conductive vias 206 to provide an electrical path from the termination pins 50 to the RF antenna 28. The conductive vias 206 extend through an upper surface 208 of the ceramic insert 202 and are thus exposed to the RF antenna 28 for electrical contact. Accordingly, thethermal stresses between the RF antenna 28 and the electrical termination assembly 200 are further separated through the use of the intermediate conductive layer 204 and conductive vias 206. The intermediate conductive layer 204 may be a material such as W, Mo, a Mo-AIN composite, or a W-AIN composite, among others. The conductive vias 206 may be a material such as a Mo-AIN composite or a W-AIN composite, among others. Further, although two conductive vias 206 are shown, it should be understood that only one, or more than two conductive vias 206 may be employed while remaining within the scope of the present disclosure. Similar elements and features of the previously illustrated and described electrical termination assemblies, and their variations and materials as set forth above are not repeated with this form of the present disclosure for purposes of clarity.

[0044] Unless otherwise expressly indicated herein, all numerical values indicating mechanical / thermal properties, compositional percentages, dimensions and / or tolerances, or other characteristics are to be understood as modified by the word “about” or "approximately" in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.

[0045] As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

[0046] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

Claims

CLAIMSWhat is claimed is:1 . An electrical termination assembly comprising: a ceramic insert defining a plurality of bores; a plurality of liners disposed within each of the plurality of bores, each liner comprising a blind bore and a distal end face, the distal end face being exposed through the respective bore of the ceramic insert; and a plurality of termination pins secured within each of the blind bores of the plurality of liners, wherein the plurality of liners comprise a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert and a CTE of the termination pins.

2. The electrical termination assembly according to Claim 1 , wherein the ceramic insert is an aluminum nitride (AIN) material, and the plurality of liners comprise a composite material having Molybdenum (Mo) and Tungsten (W).

3. The electrical termination assembly according to Claim 1 , wherein the ceramic insert comprises a lower flanged portion.

4. The electrical termination assembly according to Claim 1 , wherein the ceramic insert comprises an upper flanged portion.

5. The electrical termination assembly according to Claim 1 , further comprising a plurality of bond layers disposed between the plurality of termination pins and the plurality of liners.

6. The electrical termination assembly according to Claim 5, wherein the bond layer is selected from the group consisting of a braze layer, a solid state bond layer, and a transient liquid phase bond layer.

7. The electrical termination assembly according to Claim 1 , further comprising a sheath disposed around a proximal end portion of the termination pins.

8. A ceramic assembly comprising: a ceramic body comprising at least one recess; at least one electrical component embedded within the ceramic body; and an electrical termination assembly disposed within the recess, the electrical termination assembly comprising: a ceramic insert disposed within the ceramic body, the ceramic insert defining a plurality of bores; a plurality of liners disposed within each of the plurality of bores, each liner comprising a blind bore and a distal end face, the distal end face being exposed through the respective bore of the ceramic insert; and a plurality of termination pins secured within each of the blind bores of the plurality of liners, wherein the plurality of liners comprise a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert and a CTE of the termination pins.

9. The ceramic assembly according to Claim 8, wherein the electrical termination assembly is bonded to the ceramic body.

10. The ceramic assembly according to Claim 8, further comprising a bond layer disposed between the distal end face of the plurality of liners and the electrical component.11 . The ceramic assembly according to Claim 10, wherein the bond layer is selected from the group consisting of a braze layer, a solid state bond layer, and a transient liquid phase bond layer.

12. The ceramic assembly according to Claim 8, further comprising a sealing layer disposed between an exterior surface of the ceramic insert and the ceramic body.

13. The ceramic assembly according to Claim 12, wherein the ceramic insert comprises a lower flanged portion.

14. The ceramic assembly according to Claim 13, wherein the sealing layer is disposed between the exterior surface of the ceramic insert and an upper surface of the lower flanged portion.

15. The ceramic assembly according to Claim 12, wherein the sealing layer comprises a glass material.

16. The ceramic assembly according to Claim 8, wherein the ceramic insert comprises an upper flanged portion.

17. The ceramic assembly according to Claim 8, further comprising a sheath disposed around a proximal end portion of the termination pins.

18. A ceramic pedestal assembly comprising: a ceramic pedestal comprising at least one recess; a radio frequency (RF) antenna embedded within the ceramic pedestal; an electrical termination assembly disposed within the recess, the electrical termination assembly comprising: a ceramic insert disposed within the ceramic pedestal, the ceramic insert defining a plurality of bores; a plurality of liners disposed within each of the plurality of bores, each liner comprising a blind bore and a distal end face, the distal end face being exposed through the respective bore of the ceramic insert; and a plurality of termination pins secured within each of the blind bores of the plurality of liners, wherein the plurality of liners comprise a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert and a CTE of the termination pins; and a bond layer disposed between the distal end face of the plurality of liners and the RF antenna.

19. The ceramic pedestal assembly according to Claim 18, further comprising a resistive heater embedded within the ceramic pedestal.

20. The ceramic pedestal assembly according to Claim 18, further comprising a sheath disposed around a proximal end portion of the termination pins.21 . An electrical termination assembly comprising: a ceramic insert defining a plurality of bores; a plurality of liners disposed within each of the plurality of bores, each liner comprising a blind bore and a distal end face, the distal end face being exposed through the respective bore of the ceramic insert; a plurality of termination pins secured within each of the blind bores of the plurality of liners; an intermediate conductive layer in electrical contact with the plurality of liners; and at least one conductive via in electrical contact with the intermediate conductive layer and extending through an upper surface of the ceramic insert, wherein the plurality of liners comprise a ceramic material having a coefficient of thermal expansion (CTE) between a CTE of the ceramic insert and a CTE of the termination pins.

Images