Package wrap-around heat spreader

Embodiments disclosed herein include electronic packages and thermal solutions for such electronic packages. In an embodiment, an electronic package comprises, a package substrate with a first surface, a second surface opposite from the first surface, and a sidewall surface connecting the first surface to the second surface. In an embodiment, the electronic package further comprises a heat spreader, where a first portion of the heat spreader is attached to the first surface of the package substrate and a second portion of the heat spreader is attached to the second surface of the package substrate. In an embodiment, a third portion of the heat spreader adjacent to the sidewall surface of the package substrate connects the first portion of the heat spreader to the second portion of the heat spreader.

TECHNICAL FIELD

Embodiments of the present disclosure relate to semiconductor devices, and more particularly to wrap-around heat spreaders to provide improved thermal control of multi-die packages.

BACKGROUND

Higher performance, lower cost, and greater packaging density of integrated circuits are ongoing goals of the microelectronic industry. To achieve these goals, microelectronic devices are continuously miniaturized and/or stacked in 3D architectures. While 3D architectures allow for improved density, thermal management becomes a significant challenge for such devices due to the high power density of the components, the compounding impact of hot spots from multiple dies, and the high thermal resistance usually experienced by the bottom dies. Thermal management is a critical concern for 3D packages, because the integrated circuits in those devices may be damaged or destroyed if the temperature of the microelectronic device raises too high.

However, existing thermal solutions, such as an integrated heat spreader (IHS) that interfaces with only the top dies, do not provided the needed cooling for the bottom dies in a stack. For example, the primary thermal path from the bottom die in a multi-die stack to the IHS passes through low thermal conductivity layers such as underfill or mold compound. Similarly, in double sided systems (i.e., with a die module both above and below the package substrate), the primary thermal path from the bottom die module to the IHS passes through the package substrate.

Underfills, mold compounds, and package substrates are predominantly made of organic materials, and improvements to thermal conductivity of organic materials are severely limited by material properties. Additionally, attempts to reduce thermal resistance by improving the performance of the thermal interface material (TIM) or underfills only provides incremental improvements. Such incremental improvements do not scale with future generations as the power dissipated by the dies continues to increase. In the case of a double sided system, a second thermal solution (e.g., a second IHS) for the bottom die is not always possible due to cost and size limitations.

EMBODIMENTS OF THE PRESENT DISCLOSURE

As noted above, thermal management of 3D packaging architectures is limited by layers or components such as underfills, mold compounds, or package substrates that have a low thermal conductivity. Accordingly, heat is not easily propagated from the bottom dies to the integrated heat spreader (IHS). Therefore, embodiments disclosed herein include thermal solutions that provide high thermal conductivity paths from the bottom dies to the IHS.

In a particular embodiment, the high thermal conductivity path includes a flexible heat spreader that wraps around the package substrate. Such a heat spreader may be referred to as a wrap-around heat spreader (WAHS). A first portion of the WAHS may be secured to the top surface of the package substrate and a second portion of the WAHS may be secured to the bottom surface of the package substrate. A third portion of the WAHS wraps along the sidewall of the package substrate to connect the first portion of the WAHS to the second portion of the WAHS. In an embodiment, supports of the IHS are secured to the first portion of the WAHS.

In an embodiment, the WAHS has high in-plane thermal conductivity. For example, the WAHS may comprise graphene or high conductivity graphite sheets, a heat pipe, a vapor chamber, or the like. In some embodiments, thermal features (e.g., vias, thermal slugs, etc.) that pass through a thickness of the package substrate may thermally couple the bottom dies to the WAHS. Accordingly, a high thermal conductivity path from the bottom dies to the IHS is provided.

In some embodiments, the electronic package comprises a first die module on a top surface of the package substrate and a second die module on the bottom surface of the package substrate. In such embodiments, the WAHS provides a high thermal conductivity path from the bottom die module to the IHS. As such, there is no need for a second thermal solution dedicated to the bottom die module.

Referring now toFIG.1A, a cross-sectional illustration of an electronic package100is shown, in accordance with an embodiment. InFIG.1A, a die module140and an integrated heat spreader (IHS)150are illustrated with dashed lines to indicate that any suitable die module140or IHS150may be integrated with the electronic package100. More detailed descriptions of the die module140and the IHS150are provided below.

In an embodiment, the electronic package100comprises a package substrate110. The package substrate may be an organic package substrate. The package substrate110may comprise a plurality of layers laminated over each other. For example, the package substrate110may comprise a plurality of layers of buildup film (BF), or the like. In an embodiment, the package substrate110may comprise conductive features (e.g., traces, vias, etc.) for routing electrical paths from a first surface111of the package substrate110to a second surface112of the package substrate110. The conductive features for electrical routing are not shown for simplicity.

However, thermal routing is shown in the package substrate110. For example, one or more thermal vias115may pass from the first surface111to the second surface112of the package substrate. Accordingly, heat generated from the die module140may rapidly pass from the first surface111to the second surface112of the package substrate110, despite the low thermal conductivity of the organic material of the package substrate110. In an embodiment, the thermal vias115are dedicated for thermal purposes. That is, in some embodiments, the thermal vias115are not held at any particular voltage. In other embodiments, the thermal vias115may be part of a ground plane and, therefore, may be held at a certain voltage. In the illustrated embodiment, the thermal vias115are shown as having substantially vertical sidewalls. In other embodiments, the thermal vias115may have tapered sidewalls, typical of laser drilling in package manufacturing. Additionally, the thermal vias115may include alternating vias and pads through a thickness of the package substrate110.

In an embodiment, the electronic package100may further comprise a WAHS120. In an embodiment, the WAHS may comprise a first portion121secured to the first surface111, a second portion122secured to the second surface112, and a third portion123that wraps along a sidewall surface113of the package substrate110. In an embodiment, the first portion121may be secured to the first surface111with a sealant132or other adhesive material. In an embodiment, the second portion122is secured to the second surface112with a thermal interface material (TIM)131. The use of a TIM allows for thermal energy to pass from the thermal vias115to the WAHS120with minimal thermal resistance. In an embodiment, TIMs disclosed herein may be any suitable TIM materials, such as solder or polymer TIMs, or adhesives with high thermal conductivities (e.g., metal filled epoxies).

In an embodiment, the WAHS120has a high in-plane thermal conductivity. The high in-plane thermal conductivity allows for thermal energy to easily propagate between the second portion122and the first portion121. In a particular embodiment, the WAHS120comprises a flexible material. The use of a flexible material allows for a monolithic WAHS120to wrap over the sidewall113between the first portion121and the second portion122. In an embodiment, the WAHS120may comprise graphene or high conductivity graphite sheets, a heat pipe, a vapor chamber, or any combination thereof.

In an embodiment, the first portion121of the WAHS120may be thermally coupled to the IHS150. Particularly, supports152extending down from a main body151are coupled to the first portion121of the WAHS120. For example, a TIM133may be between the supports152and the first portion121of the WAHS120. Accordingly, a low thermal resistance path from the die module140to the IHS150is provided. In an embodiment, the primary low thermal resistance path may include the thermal vias115, the TIM131, the WAHS120, the TIM133, and the supports152of the IHS150. Such a low thermal resistance path allows for improved thermal control of the die module140since the primary thermal path no longer needs to pass through organic materials such as mold or underfill layers (not shown) in the stack comprising the die module.

In an embodiment, a pair of WAHSs120are provided along opposing sidewalls113of the package substrate110. In some embodiments, a single WAHS120is provided. In other embodiments, more than two WAHSs120may be included, as will be described in greater detail below.

In an embodiment, the WAHS120may have any suitable dimensions to accommodate the architecture of the electronic package100. For example, the WAHS120may be routed around interconnects or other components on the surfaces111or112of the package substrate110. In a particular embodiment, a first length L1of the first portion121may be smaller than a second length L2of the second portion122. For example, the first length L1may be such that the first portion121remains outside of a footprint of the die module140, and the second length L2may be such that the second portion122at least partially extends under the footprint of the die module140. Extending the second portion122under the footprint of the die module140allows for the primary thermal path to be substantially vertical through a thickness of the package substrate110. That is, horizontal propagation of the thermal energy may be implemented by the WAHS120that has superior in-plane thermal conductivity.

Referring now toFIG.1B, a cross-sectional illustration of an electronic package100is shown, in accordance with an additional embodiment. In an embodiment, the electronic package100inFIG.1Bmay be substantially similar to the electronic package100inFIG.1A, with the exception that a second die module141is attached to the second surface112of the package substrate110. The second die module141may be thermally coupled to the WAHS120. As such, heat generated by the second die module141may be propagated to the IHS150over the first surface111without needing to pass through a thickness of the package substrate110. Therefore, a second thermal solution (e.g., a second IHS) dedicated to the second die module141is not needed. This provides a cost and size savings for the electronic package100.

Referring now toFIG.1C, a cross-sectional illustration of an electronic package100is shown, in accordance with an embodiment. In an embodiment, the electronic package100is substantially similar to the electronic package100inFIG.1A, with the exception that the thermal vias115are augmented by thermal slugs116. In an embodiment, one or more thermal slugs116may be embedded into the package substrate110. The thermal slugs116comprise a high thermal conductivity material. In a particular embodiment, the thermal slugs116comprise copper or other metallic material. The thermal slugs116provide additional thermal mass along the primary thermal path from the die module140to the IHS150. In an embodiment, the thermal slugs116may be thermally coupled to one or more thermal vias115. For example, a thermal trace117may connect the thermal slug116to the thermal via115. In an embodiment, the thermal slugs116may directly interface with the TIM131. The thermal slugs116may also increase a surface area of thermally conductive material that interfaces with the TIM131and the WAHS120. Accordingly, the WAHS120is able to extract more thermal energy from the die module140.

Referring now toFIG.1D, a cross-sectional illustration of an electronic package100is shown, in accordance with an additional embodiment. The electronic package100inFIG.1Dmay be substantially similar to the electronic package100inFIG.1C, with the exception that the thermal slugs116are thermally coupled to one or more components161or162embedded in the substrate110.

In one embodiment, component161may be a thermoelectric cooler (TEC). The TEC161may be positioned below the die module140. A TEC161may provide active cooling to the die module140. That is, a first surface (facing the die module140) of the TEC161may be a cooling surface and a second surface (facing away from the die module140) may be a heating surface. The heating surface may be thermally coupled to the WAHS120by a thermal slug116or the like. Accordingly, heat generated by the TEC161is rapidly removed from the package substrate110and propagated to the IHS150by the WAHS120.

In another embodiment, additional components162may also be thermally controlled by being thermally coupled to a WAHS120. Components162may include any discrete component suitable for electronic packaging. For example, the components162may be passive components, such as capacitors, voltage regulators, passive bridges, or the like. In an embodiment, the additional components162may also comprise active components, such as a die, an active bridge, or the like.

Referring now toFIG.2A, a cross-sectional illustration that more clearly depicts a structure of a WAHS220is shown, in accordance with an embodiment. As shown, the WAHS220may have a first portion221that is secured to a first surface211of a package substrate210by a sealant232or the like, and a second portion222that is secured to a second surface212of the package substrate210by a TIM231. In an embodiment, a third portion223of the WAHS220attaches the first portion221to the second portion222.

In an embodiment, the WAHS220is a monolithic structure. That is, the first portion221, the second portion222, and the third portion223are part of a single monolithic component. For example, the WAHS220may be a flexible body that is able to be wrapped around the sidewall213of the package substrate210. As shown, the WAHS220may have curved corners227indicative of the WAHS220bending.

In some embodiments, the WAHS220is not secured to the sidewall surface213of the package substrate210. For example, as shown inFIG.2A, the third portion223is spaced away from the sidewall213by a gap G. In other embodiments, the WAHS220may be in direct contact with the sidewall213. That is, there may not be a gap G between the third portion223and the sidewall213.

Referring now toFIG.2B, a cross-sectional illustration that more clearly depicts an alternative structure of a WAHS220is shown, in accordance with an additional embodiment. In an embodiment, the third portion223of the WAHS220may be secured to the sidewall213of the package substrate210. For example, a portion of the TIM231may wrap around the corner and extend along the sidewall213. As such, additional portions of the package substrate210may be thermally coupled to the WAHS220in order to further improve thermal performance. In other embodiments, the TIM231on the sidewall213may be replaced with any suitable adhesive.

Referring now toFIG.3A, a top view illustration of the package substrate310is shown, in accordance with an embodiment. In the illustrated view, the first surface311of the package substrate310is shown. In an embodiment, a pair of WAHSs320extend over the first surface311. For example, a first WAHS320A wraps around the left edge of the package substrate310and a second WAHS320B wraps around the right edge of the package substrate310. As shown, the first portions321of the WAHSs320extend towards the center of the package substrate310. The area of the first portions321may be suitable for accepting supports of an IHS (not shown). In the illustrated embodiment, the first WAHS320A and the second WAHS320B are shown as being on opposite edges of the package substrate310. However, it is to be appreciated that WAHSs320may be on any of the edges of the package substrate310, depending on the routing and thermal requirements of the electronic package.

Referring now toFIG.3B, a top view illustration of the package substrate310is shown, in accordance with an additional embodiment. As shown, the package substrate310comprises a plurality of WAHSs320A-D. For example, a WAHS320is located over each of the four edges of the package substrate. In the illustrated embodiment, each edge of the package substrate310comprises a single WAHS320. However, in additional embodiments, one or more edges of the package substrate310may comprise a plurality of WAHSs320, depending on the routing and thermal requirements.

Referring now toFIG.4A, a cross-sectional illustration of an electronic package400is shown, in accordance with an embodiment. In an embodiment, the electronic package400may comprise a package substrate410and a die module440over the package substrate410. An IHS450may be thermally coupled to a top surface of the die module440. For example, a main body451of the IHS450may be thermally coupled to the top surface of the die module440by a TIM448. In an embodiment, the IHS450may also comprise one or more supports452that extend down towards the package substrate410.

In an embodiment, the die module440may comprise a plurality of dies and have a 3D architecture. For example, the illustrated die module440may comprise a first die442, and a plurality of second dies443that are attached to the backside surface of the first die442by interconnects445. In an embodiment, the second dies443may be electrically coupled to the first die442by vias (not shown) through the first die442. In an embodiment, the second dies443may be embedded in a mold layer446, such as epoxy.

In the illustrated embodiment, a single first die442is shown. Alternative embodiments may include a plurality of first dies442. For example, a plurality of first dies442may be electrically coupled together by a bridge embedded in the package substrate410. In an embodiment, the first die442is electrically coupled to the package substrate410by interconnects444. In an embodiment, the interconnects444may be surrounded by an underfill447. In an embodiment, the underfill447may be optimized for thermal performance. For example, the underfill447may be an epoxy with high thermal conductivity fillers or the like.

3D architectures, such as the one illustrated inFIG.4Aprovide significant thermal challenges. While the backside surfaces of the second dies443are directly connected to the main body451of the IHS450by the TIM448, there is no direct thermal path to the IHS450for the bottom first die442. Accordingly, embodiments disclosed herein include a primary thermal path that passes through the package substrate410and wraps around the sidewall413outside of the package substrate410, and back to the supports452of the IHS450over the first surface411of the package substrate410.

In an embodiment, the primary thermal path through the package substrate410may include thermal vias415. The thermal vias415may be below a footprint of the first die442. In some embodiments, the thermal vias415pass through an entire thickness of the package substrate410. For example, the pair of thermal vias415on the right side of the package substrate410pass through the entire thickness of the package substrate410. In other embodiments, thermal vias415may optionally be used in conjunction with other thermal features. For example, thermal vias415may be thermally coupled to traces417and/or thermal slugs416embedded in the package substrate410.

In an embodiment, the primary thermal path for heat transferred from the bottom die442to the IHS450outside of the package substrate410is provided along the WAHS420. The WAHS420may comprise a first portion421secured to the first surface411of the package substrate410, and a second portion422secured to the second surface412of the package substrate410. A third portion423passes over the sidewall413of the package substrate410and connects the first portion421to the second portion422. In an embodiment, the WAHS420is a monolithic structure that is flexible to allow for the attachment to both the first surface411and the second surface412of the package substrate410. The WAHS420is a structure with a high in-plane thermal conductivity. For example, the WAHS420may comprise high conductivity graphite or graphene sheets, a heat pipe, or a vapor chamber.

In an embodiment, the first portion421of the WAHS420is secured to the first surface411of the package substrate410by a sealant432or other adhesive. In an embodiment, the second portion422of the WAHS420is secured to the second surface412of the package substrate410by a TIM431. The use of a TIM431allows for improved thermal propagation from the bottom of the thermal features in the package substrate410(e.g., thermal vias415, thermal slugs416, etc.) to the WAHS420. In an embodiment, the TIM431is over an entire interface between the WAHS420and the second surface412of the package substrate410. This allows for thermal energy to be pulled from the package substrate410even outside of the thermal features (e.g., thermal vias415, thermal slugs416, etc.).

In an embodiment, the second portion422of the WAHS420extends below a footprint of the first die442. Accordingly, the primary thermal path through the package substrate410may be a substantially vertical path in some embodiments. For example, on the right side of the package substrate410, thermal vias415drop vertically from below the first die442and are thermally coupled to the second portion422of the WAHS420by the TIM431.

In an embodiment, the second portion422of the WAHS420is routed to avoid the interconnects463. As shown, the second level interconnects (SLIs)463are positioned between the pair of second portions422. In an embodiment, a thickness of the WAHSs420is also smaller than the standoff height of the SLIs463. Accordingly, standard mounting processes may be used to secure the electronic package400to a board or the like.

In an embodiment, the thermal features may also route thermal energy from locations below the first die442to the periphery of the package substrate410. For example, one or more hot spots at various locations of the first die442may be thermally coupled to the WAHS420. An example of such routing is provided on the left side of the package substrate410. As shown, a via415may be located below a hot spot of the first die442and route the thermal energy towards the periphery by using thermal traces417or the like. In the illustrated embodiment, the thermal trace417is connected to a thermal slug416. The thermal slug416is thermally coupled to the second portion of the WAHS420by the TIM431.

In an embodiment, the WAHSs420are thermally coupled to the supports452of the IHS450. As shown, each of the supports452may land on a first portion421of a WAHS420. Thermal coupling between the bottom surface of the supports452and the top surface of the first portion421of the WAHS420may be improved by utilizing a TIM433at the interface.

Referring now toFIG.4B, a cross-sectional illustration of an electronic package400is shown, in accordance with an additional embodiment. The electronic package400inFIG.4Bmay be substantially similar to the electronic package400inFIG.4A, with the exception that one or more components461are embedded in the package substrate410. In a particular embodiment, the component461is a TEC. In such embodiments, the cooling surface of the TEC461faces the first die442and the heating surface of the TEC461faces the bottom surface of the package substrate410. The bottom surface of the TEC461may be thermally coupled to the second portion422of the WAHS420. Accordingly, active cooling may also be used in conjunction with the WAHS420to provide even greater thermal control of the electronic package400.

Referring now toFIG.4C, a cross-sectional illustration of an electronic package400is shown, in accordance with an additional embodiment. In an embodiment, the electronic package400comprises a first die module440and a second die module441. In an embodiment, the first die module440is attached to the first surface411of the package substrate410, and the second die module441is attached to the second surface412of the package substrate410.

In an embodiment, the first die module440comprises a first die442. The first die442is thermally coupled to the main body451of the IHS450by a TIM448. The second die module441comprises a second die455. Since the second die455is on the opposite side of the package substrate410, there is no direct connection to the IHS450. Accordingly, embodiments include using the WAHSs420to route thermal energy from the second die455to the supports452of the IHS450.

In an embodiment, the second die455is attached to the second surface412of the package substrate410by interconnects457. The interconnects457may be surrounded by an underfill456. In an embodiment, the underfill456is a high thermal conductivity underfill456. For example, the underfill456may comprise epoxy with high thermal conductivity fillers or the like. The underfill456may be in direct contact with the second portions422of the WAHSs420. Accordingly, thermal energy from the second die455is propagated through the underfill456to the WAHS420, and up to the support452of the IHS450. Accordingly, the thermal energy does not need to pass through the organic package substrate410that has a low thermal conductivity.

Referring now toFIG.4D, a plan view illustration of the second surface412of the electronic package400inFIG.4Cis shown, in accordance with an embodiment. As shown, the second portions422extend along the second surface412and are in contact with the underfill456. In some embodiments, the second portions422extend below the underfill456. The plan view illustration also depicts the clearance for the SLIs463. As shown, the SLIs463are in rows that are out of the plane illustrated inFIG.4C.

Referring now toFIG.5, a cross-sectional illustration of an electronic system590is shown, in accordance with an embodiment. In an embodiment, the electronic system590comprises an electronic package500that is secured to a board591. The board591may be a motherboard or the like. In an embodiment, the electronic package500is attached to the board591with interconnects563. In the illustrated embodiment, the interconnects563are shown as solder balls, but it is to be appreciated that any suitable interconnect architecture may be used so long as there is clearance for the WAHS520. For example, a standoff height T1of the interconnects563will be larger than a combined thickness T2of the second portion522of the WAHS520and any adhesive (or TIM) used to secure the second portion522to the second surface512.

In an embodiment, the electronic package500comprises a package substrate510, a WAHS520, a die module540, and an IHS550. In an embodiment, the die module540may comprise one or more dies. For example, a 3D die architecture is shown inFIG.5. While an electronic package500with a single die module540over a first surface511of the package substrate510is shown, it is to be appreciated that electronic packages500with any number of die modules540over one or both surfaces511and512may be included in the electronic package500.

In an embodiment, the WAHS520comprises a first portion521on the first surface511of the package substrate510, a second portion522on the second surface512of the package substrate510, and a third portion523that wraps along a sidewall surface513of the package substrate510. The WAHS520may be thermally coupled to thermal features515and/or516in the package substrate510and to the IHS550by a TIM or the like.

FIG.6illustrates a computing device600in accordance with one implementation of the invention. The computing device600houses a board602. The board602may include a number of components, including but not limited to a processor604and at least one communication chip606. The processor604is physically and electrically coupled to the board602. In some implementations the at least one communication chip606is also physically and electrically coupled to the board602. In further implementations, the communication chip606is part of the processor604.

The processor604of the computing device600includes an integrated circuit die packaged within the processor604. In some implementations of the invention, the integrated circuit die of the processor604may be part of an electronic package that comprises a WAHS that wraps from a first surface to a second surface of the package substrate, in accordance with embodiments described herein. The term “processor” may refer to any device or portion of a device that processes electronic data from registers and/or memory to transform that electronic data into other electronic data that may be stored in registers and/or memory.

The communication chip606also includes an integrated circuit die packaged within the communication chip606. In accordance with another implementation of the invention, the integrated circuit die of the communication chip606may be part of an electronic package that comprises a WAHS that wraps from a first surface to a second surface of the package substrate, in accordance with embodiments described herein.

Example 1: an electronic package, comprising: a package substrate with a first surface, a second surface opposite from the first surface, and a sidewall surface connecting the first surface to the second surface; and a heat spreader, wherein a first portion of the heat spreader is attached to the first surface of the package substrate and a second portion of the heat spreader is attached to the second surface of the package substrate, and wherein a third portion of the heat spreader adjacent to the sidewall surface of the package substrate connects the first portion of the heat spreader to the second portion of the heat spreader.

Example 2: the electronic package of Example 1, wherein the third portion of the heat spreader is spaced away from the sidewall surface of the package substrate.

Example 3: the electronic package of Example 1, wherein the third portion of the heat spreader is secured to the sidewall surface of the package substrate.

Example 4: the electronic package of Examples 1-4, further comprising: a via through the package substrate from the first surface to the second surface, wherein the via is thermally coupled to the second portion of the heat spreader.

Example 5: the electronic package of Examples 1-4, further comprising: a thermally conductive slug embedded in the package substrate, wherein the thermally conductive slug is thermally coupled to the second portion of the heat spreader.

Example 6: the electronic package of Example 5, wherein the thermally conductive slug is thermally coupled to a component embedded in the package substrate.

Example 7: the electronic package of Example 6, wherein the component is a thermoelectric cooler, a capacitor, or a voltage regulator.

Example 8: the electronic package of Examples 1-7, wherein a first length of the first portion is smaller than a second length of the second portion.

Example 9: the electronic package of Examples 1-8, further comprising: a plurality of heat spreaders.

Example 10: the electronic package of Examples 1-9, wherein the heat spreader is flexible and wraps around the sidewall surface of the package substrate.

Example 11: the electronic package of Examples 1-10, wherein the heat spreader comprises, high thermal conductivity graphite, graphene sheets, a heat pipe, or a vapor chamber.

Example 12: an electronic package, comprising: a package substrate with a first surface and a second surface; a heat spreader that is attached to the first surface and the second surface of the package substrate; a first die module attached to the first surface of the package substrate; and an integrated heat spreader (IHS) that is thermally coupled to the heat spreader and the first die module.

Example 13: the electronic package of Example 12, wherein the first die module comprises: a first die that is attached to the first surface of the package substrate; and a plurality of second dies stacked over the first die.

Example 14: the electronic package of Example 12, further comprising: a second die module attached to the second surface of the package substrate.

Example 15: the electronic package of Examples 12-14, wherein the IHS comprises: a main body; and one or more supports extending down from the main body, wherein the main body is thermally coupled to the first die module, and wherein one or more of the supports are thermally coupled to the heat spreader.

Example 16: the electronic package of Examples 12-15, further comprising: one or more thermally conductive paths through the package substrate, wherein the one or more thermally conductive paths thermally couple the first die module to the heat spreader.

Example 17: the electronic package of Example 16, wherein the one or more thermally conductive paths comprise vias through a thickness of the package substrate.

Example 18: the electronic package of Example 16, wherein the one or more thermally conductive paths comprise metal traces or thermal slugs embedded in the package substrate.

Example 19: the electronic package of Examples 12-18, further comprising: a thermoelectric cooler with a cooling surface and a heating surface embedded in the package substrate within a footprint of the first die module, wherein the cooling surface faces the first die module, and wherein the heating surface is thermally coupled to the heat spreader by a thermally conductive path.

Example 20: the electronic package of Examples 12-19, further comprising: one or more passive devices embedded in the package substrate or on a surface of the package substrate, wherein the one or more passive devices are thermally coupled to the heat spreader by a thermally conductive path.

Example 21: the electronic package of Examples 12-20, further comprising: second level interconnects attached to the second surface of the package substrate, wherein the second level interconnects have a first thickness, and wherein the heat spreader has a second thickness that is less than the first thickness.

Example 22: the electronic package of Examples 12-21, wherein a first portion of the heat spreader attached to the first surface of the package substrate is outside of a footprint of the first die module, and wherein a second portion of the heat spreader attached to the second surface of the package substrate is at least partially within the footprint of the first die module.

Example 23: electronic system, comprising: a die module; an electronic package electrically coupled to the die module by first interconnects, wherein the electronic package comprises a first surface and a second surface opposite from the first surface; a heat spreader attached to the first surface and the second surface of the electronic package; an integrated heat spreader (IHS) thermally coupled to the die module and the heat spreader; and a board electrically coupled to the electronic package by second interconnects.

Example 24: the electronic system of Example 23, wherein the heat spreader is flexible and wraps around a sidewall surface of the electronic package.

Example 25: the electronic system of Example 23 or Example 24, wherein the heat spreader comprises, high thermal conductivity graphite, graphene sheets, a heat pipe, or a vapor chamber.