TWI866505B - Electronic package - Google Patents

Abstract

An electronic package comprising a carrier structure with a carrier surface, an electronic component being connected and set onto the carrier surface, a heat dissipation structure, a heat conduction object set on the electronic component and connected to the heat dissipation structure, and a Intermetallic Compound (IMC) layer formed between the heat dissipation structure and the heat conduction object. By the implementation of the present invention, the connection between the heat dissipation structure and the heat conduction object can be reinforced by the formation of a IMC layer between them, then to improve the efficiency of the heat conduction and the heat dissipation effect of the electronic package, and to ensure the reliability and the lifetime of the same.

Description

Electronic packaging

The present invention relates to an electronic package, in particular to an electronic package with a heat dissipation structure.

With the rise and rapid development of various applications and technologies that require high-speed computing, such as e-sports games, high-resolution multimedia and autonomous driving, as well as the demand for miniaturization of related equipment, the number of components contained in semiconductor chips (ICs) using packaging structures such as flip chip ball grid array (FCBGA) is not only increasing, but the processing and computing speeds are also getting faster and faster, making the heat generated more and more considerable, and the requirements for heat dissipation structures are also getting higher and higher.

FIG1 is a cross-sectional schematic diagram of a conventional semiconductor package 1. As shown in FIG1, the semiconductor package 1 includes a package substrate 10, a semiconductor chip 11 mounted on the upper side of the package substrate 10 in a flip-chip manner, and a heat sink 12. The heat sink 12 is disposed on the upper surface of the semiconductor chip 11 through a thermal interface material (TIM) 13, and the support legs 121 of the heat sink 12 are mounted on the package substrate 10 through an adhesive layer 14. In order to transfer the heat generated by the semiconductor chip 11 to the heat sink 12 more quickly and effectively, in recent years, liquid metal (Liquid Metal) is often used as the thermal interface material 13, so as to improve the conduction efficiency on the path from the semiconductor chip 11 to the heat sink 12 by virtue of its high thermal conductivity of 80-128W/mK. However, on the other hand, since the heat sink 12 is mostly made of metal (mainly copper), in order to prevent oxidation of its surface, the surface of the heat sink 12 is usually coated with a metal anti-oxidation layer 122, but the nickel (Ni) component and the main component gallium (Ga) in the liquid metal thermal interface material (TIM) 13 need a long time to react, that is, the nickel must be dissolved into the gallium before the two will gradually combine. This results in poor bonding between the heat sink 12 and the liquid metal thermal interface material (TIM) 13, and even generates a gap g, which results in a loss of heat conduction and dissipation performance. Therefore, how to overcome the above-mentioned problems of the known technology has become a problem that needs to be solved urgently.

In view of the various deficiencies of the above-mentioned prior art, the present invention provides an electronic package, which includes: a supporting structure; an electronic component disposed on the supporting surface; a heat conductor disposed on the electronic component; a heat dissipation structure disposed on the electronic component, and the heat conductor is sandwiched between the electronic component and the heat dissipation structure; and an intermetallic compound layer formed between the heat dissipation structure and the heat conductor.

In the aforementioned electronic package, the heat dissipation structure is a binary compound material, and the intermetallic compound layer is formed by the binary compound material and the heat conductor.

In the aforementioned electronic package, the heat conductor is a thermal interface material (TIM) layer.

In the aforementioned electronic package, the thermally conductive interface material layer is composed of a liquid metal.

In the aforementioned electronic package, the binary compound material is a copper/nickel alloy, and the liquid metal contains gallium (Ga).

In the aforementioned electronic package, the intermetallic compound layer is copper gallium (CuGa ₂ ).

In the aforementioned electronic package, the content ratio of copper to nickel in the binary compound material is 3:1.

In the aforementioned electronic package, the copper content of the binary compound material is at least 60%~90%.

In the aforementioned electronic package, the nickel content in the binary compound material is at least 10%~30%.

In the aforementioned electronic package, the thickness of the intermetallic compound layer is less than or equal to 10μm.

By implementing the present invention, a metal compound layer can be formed between the heat dissipation structure and the heat conductor in the electronic package to strengthen the bonding effect between the heat dissipation structure and the heat conductor, thereby improving the heat conduction efficiency and heat dissipation effect inside the electronic package, and ensuring the reliability and life of the electronic package.

1:Semiconductor packages

10:Packaging substrate

11: Semiconductor chip

12: Heat sink

121: Support your feet

122: Metal anti-oxidation layer

13: Thermal conductive interface material

14: Adhesive layer

2: Electronic packaging

21: Load-bearing structure

211: Loading surface

22: Electronic components

23: Heat dissipation structure

231: Top piece

232: Support your feet

24: Heat conductor

241: Boundary metal compound layer

g: gap

d:Thickness

Figure 1 is a schematic cross-sectional view of a conventional semiconductor package.

Figure 2 is a schematic cross-sectional view of the electronic package of the present invention.

The following is a specific and concrete example to illustrate the implementation of the present invention. People familiar with this technology can easily understand other advantages and effects of the present invention from the content disclosed in this manual.

It should be noted that the structures, proportions, sizes, etc. depicted in the drawings attached to this specification are only used to match the contents disclosed in the specification for understanding and reading by people familiar with this technology, and are not used to limit the restrictive conditions for the implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "above", "first", "second" and "one" used in this specification are only used to facilitate the clarity of the description, and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be regarded as the scope of implementation of the present invention.

FIG2 is a schematic cross-sectional view of the electronic package of the present invention. As shown in FIG2 , the electronic package 2 of the present embodiment includes: a supporting structure 21 having a supporting surface 211; an electronic component 22 disposed on the supporting surface 211; a heat dissipation structure 23; a heat conductor 24 disposed on the electronic component 22 and combined with the heat dissipation structure 23; and an intermetallic compound layer 241 formed between the heat dissipation structure 23 and the heat conductor 24.

The supporting structure 21 is, for example, a package substrate with a circuit layer, a silicon interposer (TSI) with conductive through-silicon vias (TSV), or other board types, and has a supporting surface 211. The circuit layer is, for example, a fan-out redistribution layer (RDL).

It should be understood that the supporting structure 21 can also be a substrate, component or structure of other supporting components, such as a lead frame, a wafer, or other plates with metal routing, etc., and is not limited to the above.

The electronic component 22 is mounted on the support surface 211 of the support structure 21 and is electrically connected to the circuit layer (not shown) in the support structure 21. The electronic component 22 can be an active component, a passive component, a package structure or a combination thereof. The active component can be, for example, an application processor (AP) or other computing chip for mobile devices such as mobile phones, and the passive component can be, for example, a resistor, a capacitor, and an inductor.

The heat dissipation structure 23 is, for example, a heat sink, a heat dissipation cover (Lid) or other components or structures with equivalent functions. In this embodiment, a heat dissipation cover is used as an example. The heat dissipation structure 23 has a top plate 231 and a supporting foot 232. The supporting foot 232 is fixedly coupled to the supporting surface 211 around the electronic component 22, and the bottom surface of the top plate 231 is opposite to the top surface of the electronic component 22.

In order to protect the heat dissipation structure 23 from oxidation even if it is in contact with air for a long time, the present embodiment adopts the method of making the heat dissipation structure 23 entirely made of binary compound material to avoid the problem of poor bonding between the anti-oxidation surface layer formed on the outer surface of the heat dissipation structure and the thermal conductive interface material of the liquid metal material. At the same time, eliminating the plating process can also simplify the overall manufacturing process and reduce costs.

The binary compound material used in this embodiment is a copper/nickel alloy, such as cupronickel. Cupronickel has high oxidation resistance and a thermal conductivity of up to 40W/m.K. Therefore, the heat dissipation structure 23 made of it can have fast heat conduction and accelerate heat dissipation, and will not cause oxidation problems during long-term use.

A heat conductor 24 is further provided between the top surface of the electronic component 22 and the bottom surface of the top sheet 231 of the heat dissipation structure 23 to more efficiently transfer the heat generated by the electronic component 22 to the heat dissipation structure 23 and then dissipate it into the environment. Preferably, the heat conductor 24 is a thermal interface material (TIM) layer. More preferably, the thermal interface material layer of this embodiment is made of a liquid metal, and the liquid metal contains gallium (Ga).

As mentioned above, the heat dissipation structure 23 in this embodiment is made of a binary compound of copper/nickel alloy material, wherein nickel (Ni) can be dissolved in the liquid metal, and the excess copper (Cu) will combine with gallium in the liquid metal to form an intermetallic compound (IMC) layer 241 of copper gallium (CuGa ₂ ) material. That is, the intermetallic compound layer 241 is formed by the binary compound material and the heat conductor 24.

By combining copper and gallium in the binary compound material constituting the heat sink structure 23 and the liquid metal constituting the heat conductor 24, an intermetallic compound layer 241 is formed between the heat sink structure 23 and the heat conductor 24, so that the intermetallic compound layer 241 can form a stable bond with both the heat sink structure 23 above and the heat conductor 24 below, thereby achieving the effect of strengthening the bond between the heat sink structure 23 and the heat conductor 24.

In some embodiments, in order to achieve the best balance among bonding effect, thermal conductivity and anti-oxidation properties, the content ratio of copper to nickel in the copper/nickel alloy as the above binary compound can be set to 3:1.

In other embodiments, the copper content in the binary compound material may be set to at least 60% to 90% based on different considerations, such as the desire to achieve better thermal conductivity, or to have more copper react with gallium in the liquid metal to accelerate the formation of the intermetallic compound.

In other embodiments, based on other different considerations, for example, the anti-oxidation effect may be improved to the best without excessively compromising the thermal conductivity and the formation rate of the intermetallic compound, and the nickel content in the binary compound material may be set at 10% to 30%.

In addition, since the function of the intermetallic compound layer 241 is to improve the bonding effect between the heat dissipation structure 23 and the heat conductor 24 and provide a better heat conduction efficiency between the two, the thickness d of the intermetallic compound layer 241 does not need to be too thick. In some cases, an overly thick intermetallic compound layer 241 may even be prone to fracture. Therefore, in some embodiments, the thickness d of the intermetallic compound layer 241 may be set to be less than or equal to 10μm.

In summary, the electronic package of the present invention is a heat dissipation structure in the electronic package that is a composite material with better oxidation resistance (copper/nickel alloy) and can form an intermetallic compound layer (copper gallium) between the heat conductor (liquid metal containing gallium) to strengthen the bonding effect between the heat dissipation structure and the heat conductor, thereby improving the heat conduction efficiency and heat dissipation effect inside the electronic package to meet the heat dissipation requirements for high-speed processing and computing. At the same time, the reliability and life of the electronic package can be ensured.

The above embodiments are used to illustrate the principles and effects of the present invention, but are not used to limit the present invention. Anyone familiar with this technology can modify the above embodiments without violating the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be as listed in the scope of the patent application described below.

2: Electronic packaging

21: Load-bearing structure

211: Loading surface

22: Electronic components

23: Heat dissipation structure

231: Top piece

232: Support your feet

24: Heat conductor

241: Boundary metal compound layer

d:Thickness

Claims (8)

An electronic package includes: a supporting structure; an electronic component disposed on the supporting structure; a heat conductor disposed on the electronic component; a heat dissipation structure disposed on the electronic component and sandwiching the heat conductor between the electronic component and the heat dissipation structure; and an intermetallic compound (IMC) layer formed between the heat dissipation structure and the heat conductor, wherein the heat dissipation structure is a binary compound material, and the intermetallic compound layer is formed by the binary compound material and the heat conductor, and the thickness of the intermetallic compound layer is less than or equal to 10 μm. An electronic package as described in claim 1, wherein the heat conductor is a thermal interface material (TIM) layer. An electronic package as described in claim 2, wherein the thermally conductive interface material layer is composed of a liquid metal. An electronic package as described in claim 3, wherein the binary compound material is a copper/nickel alloy and the liquid metal contains gallium (Ga). The electronic package as claimed in claim 4, wherein the intermetallic compound layer is copper gallium (CuGa ₂ ). An electronic package as described in claim 4, wherein the content ratio of copper to nickel in the binary compound material is 3:1. An electronic package as described in claim 4, wherein the copper content in the binary compound material is at least 60% to 90%. An electronic package as described in claim 4, wherein the nickel content in the binary compound material is at least 10% to 30%.

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