THERMAL MANAGEMENT IN 2.5 D SEMICONDUCTOR PACKAGING
Lower semiconductor dies in 2.5 D semiconductor packaging configurations can be cooled by thermally coupling the lower semiconductor dies to a heat sink positioned above the interposer, to an upper semiconductor die, to a heat sink affixed beneath a substrate, or to free-flowing air circulating above the interposer or beneath the substrate. The thermal coupling can be achieved using heat pipes, thermal vias, or other conductive passage ways.
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The present invention relates generally to semiconductor technology, and in some embodiments, to an apparatus and method for thermal management in 2.5 D semiconductor packaging.
BACKGROUND2.5 D packaging and interconnect technology is a promising semiconductor packaging technology that provides costs and reliability savings over 3D packaging technology. 2.5 D packaging technology is a fast growing packaging technology which allows the integration of homogenous and non-homogenous chips on an interposer for enhanced performance and miniaturization. In some implementations, 2.5 D semiconductor packaging mounts one or more semiconductor dies on the undercarriage of the interposer, thereby positioning those semiconductor dies in a relatively tight cavity between the interposer and substrate. While this achieves a more compact semiconductor package configuration, it also raises challenges related to thermal management, as it may be quite difficult to control the operating temperature of semiconductor dies mounted beneath the interposer due to space and/or airflow limitations. Accordingly, mechanisms for controlling the operating temperature of chips mounted beneath an interposer in a 2.5 D packaging configuration are desired.
SUMMARY OF THE INVENTIONTechnical advantages are generally achieved, by embodiments of this disclosure which describe an apparatus and method for thermal management in 2.5 D semiconductor packaging.
In accordance with an embodiment, a semiconductor package is provided. In this example, the semiconductor package includes an interposer, an upper semiconductor die affixed to the interposer, and a lower semiconductor die affixed to the interposer. The interposer is positioned in-between the upper semiconductor die and the lower semiconductor die. The semi-conductor package further includes a heat sink affixed to the upper semiconductor die, and a heat pipe thermally coupling the lower semiconductor die to the heat sink.
In accordance with another embodiment, another semiconductor package is provided. In this example, the semiconductor package includes a substrate comprising one or more thermal vias, an interposer positioned above the substrate, and a lower semiconductor die affixed to the interposer. The one or more thermal vias extend through the substrate, and the lower semiconductor die is positioned in-between the substrate and the interposer. The semiconductor package further includes a heat plug affixably interposed between the lower semiconductor die and the substrate, wherein the heat plug thermally couples the lower semiconductor die to the one or more thermal vias extending through the substrate.
In accordance with yet another embodiment, a method for constructing a semiconductor package is provided. In this example, the method includes affixing a lower semiconductor die to a lower face of an interposer, affixing an upper semiconductor die to an upper face of the interposer, and affixing the interposer to an upper face of a substrate. The lower semiconductor die is positioned in-between the interposer and the substrate. In one embodiment, the method further includes thermally coupling the lower semiconductor die to a heat sink positioned above the upper semiconductor die. In another embodiment, the method further includes thermally coupling the lower semiconductor die to one or more thermal vias extending through the substrate.
For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTSThe making and using of embodiments of this disclosure are discussed in detail below. It should be appreciated, however, that the concepts disclosed herein can be embodied in a wide variety of specific contexts, and that the specific embodiments discussed herein are merely illustrative and do not serve to limit the scope of the claims. Further, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of this disclosure as defined by the appended claims.
As discussed above, space and airflow limitations make it quite difficult to control the operating temperature of semiconductor chips mounted to the lower face of an interposer in a 2.5 D semiconductor package. For purposes of clarity and concision, this disclosure will refer to semiconductor dies mounted to the lower face of an interposer in a 2.5 D semiconductor package (e.g., in the cavity between the interposer and the substrate) as lower semiconductor dies, while referring to semiconductor chips mounted to the upper face of the interposer as upper semiconductor dies. For example, the cavity between the interposer and substrate may be too small to house a heat sink of adequate size to sufficiently dissipate heat from the lower semiconductor die. Further, the cavity may be incapable of channeling a sufficient amount of free-flowing air over the lower semiconductor die (or a heat sink affixed thereto) to maintain the die's temperature within an operable range. Accordingly, mechanisms for controlling the operating temperature of lower semiconductor dies are desired.
Aspects of this disclosure provide thermal management techniques for controlling the operating temperature of lower semiconductor dies in 2.5 D semiconductor packaging configurations. One thermal management technique includes thermally coupling the lower semiconductor die to the upper semiconductor die (or to a heat sink affixed thereto) via a heat pipe. The heat pipe may be composed of any thermally conductive material (e.g., copper (Cu), high k graphite, etc.), and may be routed around the interposer. Another thermal management technique includes thermally coupling the lower semiconductor die to thermal vias extending through the substrate via a heat plug. The thermal vias may dissipate heat directly into free-flowing air that circulates beneath the substrate, or alternatively, to a heat sink positioned beneath the substrate. These techniques may be modified depending on design or functional considerations. By way of example, the heat pipe may be thermally coupled to a heat sink positioned below the substrate or in any location outside the cavity formed between the interposer and the substrate. As another example, the heat pipe may dissipate heat into free-flowing air.
In some implementations, 2.5 D semiconductor packaging may position semiconductor dies on the undercarriage of the interposer.
As shown, the cavity between the lower semiconductor dies 220 and the substrate 210 is relatively compact, and may have space and/or airflow limitations that make it difficult to control the operating temperature of lower semiconductor dies 220 within an acceptable range. For example, the cavity may be too small to house a heat sink of adequate size, or may otherwise be incapable of channeling a sufficient amount of free-flowing air to maintain the semiconductor die's 220 operating temperature within an acceptable range. Thermal management may be particularly difficult for high output dies, such as those dissipating more than 100 watts.
Embodiments of this disclosure deploy heat pipes to dissipate heat from lower semiconductor dies to a heat sink positioned above the interposer.
In some embodiments, an intermediate heat sink may be placed on the lower semiconductor dies to achieve a more efficient transfer of heat to the heat pipes.
Although
Other aspects of this disclosure use thermal vias and/or heat plugs to dissipate heat from lower semiconductor dies to free-flowing air circulating below the substrate.
In some embodiments, the thermal vias may be thermally coupled to a heat sink positioned below the substrate in order to improve heat transfer efficiency to the free-flowing air.
2.5 D packaging technology is a fast growing packaging technology which allows the integration of homogenous and non-homogenous chips on an interposer for enhanced performance and miniaturization. Aspects of this disclosure may provide the following benefits: powerful enabler for the highly popular 2.5 D and 3 D packaging technology; effective thermal management for higher power dissipation; associated 2.5 D advantages of Application-Specific Integrated Circuits (ASICs) and memory integration.
Although the description has been described in detail, it should be understood that various changes, substitutions and alterations can be made without departing from the spirit and scope of this disclosure as defined by the appended claims. Moreover, the scope of the disclosure is not intended to be limited to the particular embodiments described herein, as one of ordinary skill in the art will readily appreciate from this disclosure that processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, may perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
Claims
1. A semiconductor package comprising:
- an interposer having: an undercarriage face couplable to a substrate, and an upper face;
- an upper semiconductor die affixed to the upper face of the interposer;
- a lower semiconductor die affixed to the undercarriage face of the interposer, wherein the interposer is positioned between the upper semiconductor die and the lower semiconductor die, and wherein the lower semiconductor die, when the undercarriage face is coupled to the substrate, is positioned between the interposer and the substrate;
- a heat sink affixed to the upper semiconductor die; and
- a heat pipe thermally coupling the lower semiconductor die to the heat sink.
2. The semiconductor package of claim 1, wherein the heat pipe is configured to dissipate heat from the lower semiconductor die to the heat sink.
3. The semiconductor package of claim 1, wherein the heat pipe extends from the lower semiconductor die to the heat sink, the heat pipe being routed around the interposer.
4. The semiconductor package of claim 1, wherein the heat pipe extends from the lower semiconductor die to the heat sink, the heat pipe extending through the interposer.
5. The semiconductor package of claim 1, wherein the heat pipe is affixed to a corner of the heat sink.
6. The semiconductor package of claim 1, wherein the heat pipe is affixed directly to the lower semiconductor die.
7. The semiconductor package of claim 1, further comprising:
- an intermediate heat sink affixed to the lower semiconductor die and the heat sink, wherein the heat pipe is configured to draw heat from the lower semiconductor die through the intermediate heat sink.
8. The semiconductor package of claim 1, wherein the semiconductor package is configured in accordance with a 2.5 D semiconductor packaging technique.
9. The semiconductor package of claim 1, wherein the heat pipe comprises graphite.
10. The semiconductor package of claim 1, wherein the heat pipe comprises copper.
11-22. (canceled)
23. A semiconductor package comprising:
- an interposer having an undercarriage face couplable to a substrate;
- a lower semiconductor die affixed to the undercarriage face of the interposer, wherein the lower semiconductor die would be positioned between the interposer and the substrate when the interposer is coupled to the substrate; and
- a heat pipe thermally coupling the lower semiconductor die to a heat sink.
24. The semiconductor package of claim 23, wherein the heat pipe is configured to dissipate heat from the lower semiconductor die to the heat sink.
25. The semiconductor package of claim 23, wherein the heat pipe extends from the lower semiconductor die to the heat sink, the heat pipe being routed around the interposer.
26. The semiconductor package of claim 23 further comprising an upper semiconductor die affixed to and positioned between the heat sink and the interposer.
27. The semiconductor package of claim 23, wherein the heat pipe extends from the lower semiconductor die to the heat sink, the heat pipe extending through the interposer.
28. The semiconductor package of claim 23, wherein the heat pipe is affixed to a corner of the heat sink.
29. The semiconductor package of claim 23, wherein the heat pipe is affixed directly to the lower semiconductor die.
30. The semiconductor package of claim 23, further comprising:
- an intermediate heat sink affixed to the lower semiconductor die and the heat sink, wherein the heat pipe is configured to draw heat from the lower semiconductor die through the intermediate heat sink.
31. The semiconductor package of claim 23, wherein the semiconductor package is configured in accordance with a 2.5 D semiconductor packaging technique.
32. The semiconductor package of claim 23, wherein the heat pipe comprises graphite.
33. The semiconductor package of claim 23, wherein the heat pipe comprises copper.
Type: Application
Filed: May 10, 2013
Publication Date: Nov 13, 2014
Applicant: FutureWei Technologies, Inc. (Plano, TX)
Inventors: Anwar A. Mohammed (San Jose, CA), Vadim Gektin (San Jose, CA)
Application Number: 13/891,251
International Classification: H01L 23/34 (20060101); H01L 25/00 (20060101);