WO2019191457A1

WO2019191457A1 - Substrate with embedded copper molybdenum or copper tungsten heat slug

Info

Publication number: WO2019191457A1
Application number: PCT/US2019/024621
Authority: WO
Inventors: Helen LEUNG; Paul E. Hogan; Paul Panaccione
Original assignee: Macom Technology Solutions Holdings, Inc.
Priority date: 2018-03-29
Filing date: 2019-03-28
Publication date: 2019-10-03

Abstract

Disclosed are various embodiments of a substrate with an embedded copper molybdenum slug or an embedded copper tungsten slug. In one embodiment, among others, a substrate can include a top copper layer and a bottom copper layer. A copper molybdenum slug or a copper tungsten slug is embedded between the top copper layer and the bottom copper layer.

Description

SUBSTRATE WITH EMBEDDED COPPER MOLYBDENUM OR COPPER

TUNGSTEN HEAT SLUG

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application Serial No. 62/650,065, filed March 29, 2018, the entire contents of which are hereby incorporated herein by reference.

BACKGROUND

[0002] In electronic systems, some components have strict placement constraints on a circuit board because of their circuit functions. Optical components, as an example, have tight placement constraints on the circuit board because various parameters of the circuit board can affect the performance of the optical signal. Oftentimes, optical components are placed on reinforced plates to help maintain signal alignment accuracy over temperature.

SUMMARY OF INVENTION

[0003] The present disclosure provides various embodiments of an embedded heat slug substrate. In one example, a substrate includes a top copper layer, a bottom copper layer, and a copper molybdenum slug embedded between the top copper layer and the bottom copper layer. The copper molybdenum slug is positioned within a cavity of the substrate. The copper molybdenum slug is secured within the cavity using a non- conductive adhesive filler material. The copper molybdenum slug comprises a range of

15-30% copper and a range of 70%-85% molybdenum in one example, although other compositions can be relied upon. One or more electrical and/or optical components can be electrically secured on the top copper layer of the substrate.

[0004] In another example, a substrate includes a cavity that extends through the substrate, a top copper layer that covers a first side of the cavity, a bottom copper layer that covers a second side of the cavity, and an embedded heat distributor between the top copper layer and the bottom copper layer. The top copper layer is electrically grounded to the bottom copper layer by way of the embedded heat distributor in one example.

[0005] The embedded heat distributor comprises at least one of a copper molybdenum slug or a copper tungsten slug positioned between the top copper layer and the bottom copper layer. The embedded heat distributor includes a top embedded copper layer and a bottom embedded copper layer in one example. The substrate also includes a non-conductive adhesive filler material placed along at least one side of the cavity of the substrate, and the non-conductive adhesive filler material secures the embedded heat distributor within the cavity.

[0006] The copper tungsten slug comprises a range of 85-89% tungsten and a range of 11 -15% copper in one example, although other compositions can be relied upon. The copper molybdenum slug comprises a range of 15-30% copper and a range of 70%-85% molybdenum in one example, although other compositions can be relied upon. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, with emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0008] FIG. 1A illustrates a top view of an embedded heat distributor substrate, according to various embodiments described herein.

[0009] FIG. 1 B illustrates a cross-sectional view of the embedded heat distributor substrate of FIG. 1A, according to various embodiments described herein.

[0010] FIG. 1 C illustrates a bottom view of the embedded heat distributor substrate of FIG. 1A, according to various embodiments described herein.

[0011] FIG. 2 illustrates a cross-sectional view of another exemplary embodiment of an embedded heat distributor substrate, according to various embodiments described herein.

[0012] FIG. 3 is table of different material compositions and their property values when used as an embedded heat distributor in a substrate, according to various embodiments described herein.

[0013] FIG. 4 illustrates an array circuit board 400 with multiple embedded heat distributor substrates from FIG. 1A, according to various embodiments described herein. [0014] FIGS. 5A-5C illustrate cross-sectional views of different substrates with embedded heat distributors that have different material compositions, according to various embodiments described herein.

DETAILED DESCRIPTION

[0015] Electronic components may have tight placement constraints on circuit boards because of the nature of their circuit functions. Particularly, electronic components can require a substrate on which the electronic components are placed to have certain thermal expansion, electrical conductivity, and mechanical rigidity properties. For example, optical components can require certain substrate constraints because an optical signal can be affected by the substrate thermal expansion properties. If the substrate expands too much over a temperature range, then the substrate expansion can interfere with an alignment of an optical signal for the optical component. Oftentimes, substrates are embedded with a heat slug for the dissipation of heat.

[0016] The embodiments of the present disclosure relate to an improved embedded heat slug substrate. The embodiments provide improved substrate properties, such as good thermal dissipation, higher mechanical rigidity, and better electrical conductive paths compared to existing designs. These improve substrate properties are achieved by using material compositions, such as copper molybdenum or copper tungsten, in the disclosed arrangements. The embodiments can be used for optical sub-assembly boards, light emitting diode (LED) circuit boards, laser circuit boards, or other suitable circuit boards where energy efficiency and/or thermal dissipation are important.

[0017] Referring between FIG. 1A and FIG. 1 B, an embedded heat distributor substrate 103 (or“substrate 103”) is shown. FIG. 1A identifies the cross-sectional“A-A” reference for the view shown in FIG. 1 B. The substrate 103 comprises a top copper layer 106 on one side of the substrate 103, a bottom copper layer 115 on an opposite side of the substrate 103, and an embedded heat distributor 109 between the top copper layer 106 and the bottom copper layer 115. In various embodiments described herein, the embedded heat distributor 109 can be embodied as a heat slug embedded within the substrate 103. As described herein, the low thermal expansion properties of the substrate 103 can help facilitate optical signals with greater stability.

[0018] The top copper layer 106 can be used for the placement of components with tight constraints. In that context, the top copper layer 106 can include a layer of one or more copper traces for electrically connecting one or more electrical and optical components to each other. One or more components can be placed on and, in some cases, electrically coupled to the top copper layer 106. The bottom copper layer 115 can, in some cases, also be used for the placement of components. The bottom copper layer 115 can also include a layer of one or more copper traces. The top copper layer 106 and the bottom copper layer 115 can vary in thickness, such as a thickness from 15-25 urn, although other thicknesses can be relied upon.

[0019] Referring to FIG. 1 B, shown is a cross-sectional view of the substrate 103 shown in FIG. 1A. The embedded heat distributor substrate 103 comprises a cavity 112 in which the embedded heat distributor 109 is positioned. In the illustrated embodiment, the cavity 112 is an aperture or opening that extends through the embedded heat distributor substrate 103 from the top copper layer 106 to the bottom copper layer 115.

[0020] The embedded heat distributor 109 can be used to dissipate heat, provide mechanical stability, and provide an electrical path for a ground from the top copper layer 106 to the bottom copper layer 115. The embedded heat distributor 109 may be comprised of a composition of copper molybdenum, a copper tungsten, or other suitable material composition. For example, in one embodiment, the embedded heat distributor 109 may be comprised of a range of 15-30% copper and 70-85% molybdenum. In another embodiment, the embedded heat distributor 109 may be comprised of a range of 85-89% tungsten and a range of 11 -15% copper. One skilled in the art can appreciate that these percentages of material composition can vary. These material compositions are an improvement over existing material compositions used for substrates with embedded heat distributors. For example, copper alone has a relatively high coefficient of thermal expansion (CTE). If formed from copper alone, the embedded heat distributor 109 and/or the substrate 103 could expand to such a degree to effect the performance of the components placed on the top copper layer 106. Aluminum nitride may have relatively lower thermal expansion properties as compared to copper, but it is also an electrical insulator. Thus, aluminum nitride cannot be relied upon to improve on the ability to dissipate heat.

[0021] The embedded heat distributor 109 can be positioned within the cavity

112. The embedded heat distributor substrate 103 can comprise adhesive filler materials 121a, 121 b (collectively“adhesive filler material 121”). The adhesive filler material 121 can be comprised of a non-electrically conductive material. The adhesive filler material 121 can be used to secure the embedded heat distributor 109 within the cavity 112 of the substrate 103. In some embodiments, the adhesive filler material 121 can be an epoxy material, other suitable non-conductive adhesive material, or a combination of non-conductive adhesive materials.

[0022] The embodiments provide improved grounding performance over existing designs for multiple reasons. The disclosed material compositions of the embedded heat distributor 109 have lower electrical resistivity properties than existing designs of embedded heat distributors used in substrates. As a result, the lower electrical resistivity enables the embodiments to provide improved grounding performance.

[0023] Particularly, in some embodiments, the top copper layer 106 is electrically grounded to the bottom copper layer 115 through a center of the embedded heat distributor substrate 103. In previous designs, the substrate would have a cavity that extends through a only portion of the layers of the substrate 103. For example, in previous designs, an embedded heat distributor or an embedded heat slug may be embedded into layers 1 -6 of a 10-layer substrate, where the remaining layers 7-10 are comprised of typical substrate materials. These typical substrate materials are prone to thermal expansion and high electric resistivity.

[0024] Additionally, the disclosed material compositions of the embodiments provide improved mechanical rigidity properties. This is useful in exemplary embodiments with long, thin substrates. Also, the material compositions of these embodiments have improved performance with respect to lower coefficient thermal expansion properties for a substrate. Thus, over a range of temperatures, the embedded heat distributor substrate 103 will expand less than previous designs. This factor is significant in designs that have electronic components with strict placement and alignment parameters.

[0025] The embedded heat distributor substrate 103 can be used in optical assemblies, such as in the design of transceiver optical sub-assemblies. The embedded heat distributor substrate 103 can also be useful in light emitting diode (LED) assemblies, laser assemblies, portable assemblies, and other suitable electronic assemblies.

[0026] With reference to FIG. 1 C, shown is a bottom view of the embedded heat distributor substrate 103. FIG. 1 C illustrates the bottom copper layer 115 from FIG. 1 B. The bottom copper layer 115 can serve as a ground plane.

[0027] Moving to FIG. 2, shown is an enlarged cross-sectional view of another embedded heat distributor substrate 203 (or“substrate 203”). Similar to the substrate 103, the substrate 103 comprises a top copper layer 106 on one side of the substrate 203 and a bottom copper layer 215 on an opposite side of the substrate 203. The substrate 203 also comprises a cavity 212, wherein the 212 reference arrows indicate a length of the cavity 212. The“FI1” reference indicator refers to a height of the cavity 212, which corresponds with a height of all of the layers of the substrate 203. In the illustrated embodiment, the cavity 212 is an aperture that extends through the embedded heat distributor substrate 203 from the top copper layer 206 to the bottom copper layer 215. . The top copper layer 206 and the bottom copper layer 215 can have a length“L1 ,” which is larger than a length of the cavity 212. In some embodiments, the top copper layer 206 and the bottom copper layer 215 can have a minimum thickness of 15 urn. In some preferred embodiments, a thickness of 25 urn is desirable. [0028] The embedded heat distributor 209 can serve to dissipate heat, provide mechanical stability, and provide improved electrical grounding performance through the center of the substrate. In some embodiments, the embedded heat distributor 209 can also be referred to as a heat slug. In this embodiment, the embedded heat distributor 209 comprises a top embedded copper layer 216a, a bottom embedded copper layer 216b, and an interior heat distributor 218. The top embedded copper layer 216a and the bottom embedded copper layer 216b can be cladded coverings for the interior heat distributor 218.

[0029] The embedded heat distributor 209 can have a length“L2,” which is less than the length of the cavity 212. The interior heat distributor 218 may be comprised of a composition of copper molybdenum, a copper tungsten, or other suitable material composition. In one embodiment, the interior heat distributor 118 may be comprised of a range of 15-30% copper and 70-85% molybdenum. In another embodiment, the interior heat distributor 218 may be comprised of a range of 85-89% tungsten and a range of 11 -15% copper. One skilled in the art can appreciate that these percentages of material composition can vary. These material compositions are an improvement over existing material compositions used for heat distributors. For example, copper alone has a high CTE. If formed from copper alone, the embedded heat distributor 209 and/or the substrate 203 could expand to such a degree to effect the performance of the components placed on the top copper layer 206. Aluminum nitride may have relatively lower thermal expansion properties as compared to copper, but it is also an electrical insulator. Thus, aluminum nitride cannot be relied upon to improve on the ability to dissipate heat. [0030] The embedded heat distributor 209 can be positioned within the cavity 212. The embedded heat distributor substrate 203 can comprise an adhesive filler material 221 a, 221 b (collectively“adhesive filler material 221”). The adhesive filler material 221 can be comprised of a non-electrically conductive material. The adhesive filler material 221 can be used to secure the embedded heat distributor 209 within the cavity 212 of the substrate 203. In some embodiments, the adhesive filler material 221 can be an epoxy material, other suitable non-conductive adhesive material, or a combination of non-conductive adhesive materials.

[0031] The embodiments provide improved grounding performance over existing designs for multiple reasons. The material compositions of the interior heat distributor 218 have lower electrical resistivity properties than existing designs of heat distributors, which enables the embodiments to provide improved grounding performance.

[0032] In some embodiments, the top copper layer 206 is electrically grounded to the bottom copper layer 215 through a center of the embedded heat distributor substrate 203. In previous designs, the substrate would have a cavity that extends through only a portion of the layers of the substrate 203. For example, in previous designs, an embedded heat distributor or an embedded heat slug may be embedded into layers 1 -6 of a 10-layer substrate, where the remaining layers 7-10 are comprised of typical substrate materials. In the embodiment shown, the cavity 212 can extend through all layers of the substrate 203 between the top copper layer 206 and the bottom copper layer 215. In addition, the top copper layer 206 is electrically coupled to the top embedded copper layer 216a. The top embedded copper layer 216a and the bottom embedded copper layer 216b can be cladded coverings for the interior heat distributor 218. Then, the bottom embedded copper layer 216b is electrically coupled to the bottom copper layer 215. Thus, this arrangement of low electrical resistivity materials from the top copper layer 206 through the embedded heat distributor 209 to the bottom copper layer 215 provides for an improved grounding performance through the center of the embedded heat distributor substrate 203.

[0033] In addition to the low electric resistivity, the material compositions of the embedded heat distributor substrate 203 provide improved thermal dissipation properties as well. Additionally, the disclosed material compositions of the embodiments provide improved mechanical rigidity properties. This is particularly useful for long, thin substrates. Also, the material compositions of these embodiments have improved performance with respect to lower coefficient thermal expansion properties for a substrate. Thus, over a range of temperatures, the embedded heat distributor substrate 203 will expand less than previous designs. This factor is significant in designs that have electronic components with strict placement and alignment parameters.

[0034] The embedded heat distributor substrate 203 can be used in optical assemblies, such as in the design of transceiver optical sub-assemblies. The embedded heat distributor substrate 203 can also be useful in light emitting diode (LED) assemblies, laser assemblies, portable assemblies, and other suitable electronic assemblies.

[0035] Moving to FIG. 3, shown is a table 300 of different material composition properties for different embedded heat distributors. The table 300 includes property values related to CTE, thermal conductivity, and electric resistivity for different material compositions. Reference number 303 represents existing solutions comprised of copper or aluminum nitride. The embodiments of the present disclosure can include one of several different compositions of copper molybdenum. Specifically, the table 300 includes property values for a 30% copper and 70% molybdenum material composition and a 15% copper and 85% molybdenum material composition, which are referred to by reference number 306. The embodiments of the present disclosure can also include one of several different compositions of copper tungsten. Particularly, the table 300 includes property values for a 89% tungsten and 11 % copper material composition and a 85% tungsten and 15% copper material composition, which are referred to by reference number 309. As illustrated in the table 300, the material compositions referenced by 306, 309 have superior performance values compared to existing design with respect to the CTE, thermal conductivity, and electric resistivity properties.

[0036] As illustrated in table 300, copper has a high CTE, which indicates that it is not structurally stable over temperature and could cause a substrate to expand or warp. Aluminum nitride is a good thermal conductor, but it is an electrical insulator. Aluminum nitride has a low CTE value, but it is also an electrical insulator. Based on the need for low CTE, high thermal conductivity, and electrical conductivity, copper molybdenum and copper tungsten were considered as a good option for heat distributor materials according to the embodiments described herein. Additionally, some of the embedded heat distributors described herein include copper plating or cladding on top and bottom surfaces, such as 15 urn or more copper plating or cladding. The heat distributor material may also need to have tight thickness tolerance within +/- 25um for the substrate fabrication process. [0037] FIG. 4 illustrates an array circuit board 400 with a first embedded heat distributor substrate 103a and a second embedded heat distributor substrate 103b, among others. Although only two embedded heat distributor substrates are populated, the array circuit board 400 can populate a varying number of embedded heat distributor substrates 103.

[0038] FIGS. 5A-5C illustrate different cross-sectional views of exemplary substrates with embedded heat distributors having different material compositions. FIG. 5A illustrates a substrate with a copper tungsten heat distributor plate mounted in a cavity. In FIG. 5A, the cavity extends through some of the layers of the substrate. Flowever, in FIG 5A, the cavity does not extend all the way through from the top layer to the bottom layer.

[0039] FIG. 5B illustrates a cross-sectional view of an exemplary substrate with an embedded copper molybdenum heat distributor. FIG. 5B illustrates one example of the embodiments discussed herein. FIG. 5C illustrates a cross-sectional view of an exemplary substrate with an embedded aluminum nitride heat distributor.

[0040] In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the entire disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.

[0041] Disjunctive language such as the phrase“at least one of X, Y, or Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof ( e.g ., X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y, or at least one of Z to each be present.

[0042] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

[0043] In addition to the forgoing, the various embodiments of the present disclosure include, but are not limited to, the embodiments set forth in the following clauses.

[0044] Clause 1. A substrate, comprising: a top copper layer; a bottom copper layer; and a copper molybdenum slug embedded between the top copper layer and the bottom copper layer.

[0045] Clause 2. The substrate of clause 1 , wherein the copper molybdenum slug is positioned within a cavity of the substrate.

[0046] Clause 3. The substrate of any one of clauses 1 or 2, wherein the copper molybdenum slug is secured within the cavity using a non-conductive adhesive filler material. [0047] Clause 4. The substrate of any one of clauses 1 -3, wherein the copper molybdenum slug comprises a range of 15-30% copper and a range of 70%-85% molybdenum.

[0048] Clause 5. The substrate of any one of clauses 1 -4, wherein an optical component is electrically secured on the top copper layer of the substrate.

[0049] Clause 6. The substrate of any one of clauses 1-5, wherein the substrate comprises a cavity that extends from a top side of the substrate to a bottom side of the substrate.

[0050] Clause 7. A substrate, comprising: a cavity that extends through the substrate; a top copper layer that covers a first side of the cavity; a bottom copper layer that covers a second side of the cavity; and an embedded heat distributor between the top copper layer and the bottom copper layer, the embedded heat distributor comprising at least one of a copper molybdenum slug or a copper tungsten slug.

[0051] Clause 8. The substrate of clause 7, further comprising a non-conductive adhesive filler material placed along at least one side of the cavity of the substrate, wherein the non-conductive adhesive filler material secures the embedded heat distributor within the cavity.

[0052] Clause 9. The substrate of any one of clauses 7 or 8, wherein the copper tungsten slug comprises a range of 85-89% tungsten and a range of 11 -15% copper.

[0053] Clause 10. The substrate of any one of clauses 7-9, wherein the top copper layer has a first length that is larger than a second length of the cavity. [0054] Clause 1 1 . The substrate of any one of clauses 7-10, wherein the embedded heat distributor comprises a top embedded copper layer and a bottom embedded copper layer.

[0055] Clause 12. The substrate of any one of clauses 7-1 1 , The substrate of any one of claims 7-1 1 , wherein an optical component is electrically secured on the top copper layer of the substrate.

[0056] Clause 13. The substrate of any one of clauses 7-12, wherein the copper molybdenum slug comprises a range of 15-30% copper and a range of 70%-85% molybdenum.

[0057] Clause 14. The substrate of any one of clauses 7-13, wherein the embedded heat distributor has a first lengthen that is smaller than a second length the cavity.

[0058] Clause 15. The substrate of any one of clauses 7-14, wherein the top copper layer is electrically grounded to the bottom copper layer by way of the embedded heat distributor.

[0059] Clause 16. The substrate of any one of clauses 7-15, wherein the embedded heat distributor comprises a top embedded copper layer and a bottom embedded copper layer in between an interior heat distributor comprising the at least one of the copper molybdenum slug or the copper tungsten slug.

[0060] Clause 17. The substrate of any one of clauses 7-16, wherein at least one of the top copper layer or the bottom copper layer comprises a thickness in a range between 15 urn and 25 urn. [0061] Clause 18. The substrate of any one of clauses 7-17, wherein the top copper layer is electrically grounded to the bottom copper layer by way of an interior heat distributor between the top copper layer and the bottom copper layer.

[0062] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. In addition, all optional and preferred features and modifications of the described embodiments and dependent claims are usable in all aspects of the disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another

Claims

CLAIMS Therefore, the following is claimed:

1. A substrate, comprising:

a top copper layer;

a bottom copper layer; and

a copper molybdenum slug embedded between the top copper layer and the bottom copper layer.

2. The substrate of claim 1 , wherein the copper molybdenum slug is positioned within a cavity of the substrate.

3. The substrate of any one of claims 1 or 2, wherein the copper molybdenum slug is secured within the cavity using a non-conductive adhesive filler material.

4. The substrate of any one of claims 1-3, wherein the copper molybdenum slug comprises a range of 15-30% copper and a range of 70%-85% molybdenum.

5. The substrate of any one of claims 1 -4, wherein an optical component is electrically secured on the top copper layer of the substrate.

6. The substrate of any one of claims 1 -5, wherein the substrate comprises a cavity that extends from the top copper layer to the bottom layer of the substrate.

7. A substrate, comprising:

a cavity that extends through the substrate;

a top copper layer that covers a first side of the cavity;

a bottom copper layer that covers a second side of the cavity; and an embedded heat distributor between the top copper layer and the bottom copper layer, the embedded heat distributor comprising at least one of a copper molybdenum slug or a copper tungsten slug.

8. The substrate of claim 7, further comprising a non-conductive adhesive filler material placed along at least one side of the cavity of the substrate, wherein the non-conductive adhesive filler material secures the embedded heat distributor within the cavity.

9. The substrate of any one of claims 7 or 8, wherein the copper tungsten slug comprises a range of 85-89% tungsten and a range of 11 -15% copper.

10. The substrate of any one of claims 7-9, wherein the top copper layer has a first length that is larger than a second length of the cavity.

11. The substrate of any one of claims 7-10, wherein the embedded heat distributor comprises a top embedded copper layer and a bottom embedded copper layer.

12. The substrate of any one of claims 7-1 1 , wherein an optical component is electrically secured on the top copper layer of the substrate.

13. The substrate of any one of claims 7-12, wherein the copper molybdenum slug comprises a range of 15-30% copper and a range of 70%-85% molybdenum.

14. The substrate of any one of claims 7-13, wherein the embedded heat distributor has a first length that is smaller than a second length the cavity.

15. The substrate of any one of claims 7-14, wherein the top copper layer is electrically grounded to the bottom copper layer by way of the embedded heat distributor.

16. The substrate of any one of claims 7-15, wherein the embedded heat distributor comprises a top embedded copper layer and a bottom embedded copper layer between an interior heat distributor comprising the at least one of the copper molybdenum slug or the copper tungsten slug.

17. The substrate of any one of claims 7-16, wherein at least one of the top copper layer or the bottom copper layer comprises a thickness in a range between 15 urn and 25 urn.

18. The substrate of any one of claims 7-17, wherein the top copper layer is electrically grounded to the bottom copper layer by way of an interior heat distributor between the top copper layer and the bottom copper layer.