Patent Description:
Electronic components such as chip assemblies or integrated circuit (IC) dies are often used in electronic devices, such as tablets, computers, copiers, digital cameras, smart phones, control systems, and automated teller machines, among others. The demand for highperformance electronic devices has led to developments in electronic component designs. For instance, to increase the performance of an electronic component, the size of the electronic component is often decreased, while the number of integrated components (e.g., transistors) within the electronic component is increased. However, the decrease in size and increase in the number of components in the electronic components can lead to thermal management issues, such as overheating. Such overheating may result in device failure or electrical performance deterioration.

<CIT> discloses a column suction-holding head.

<CIT> discloses a method of manufacturing a heat transfer device, particularly a heat transfer device for cooling electronic components, having a metal plate and a plurality of cylindrical metal pins which are packed relatively densely on the plate and extend perpendicularly therefrom.

<CIT> discloses a vacuum controlled fixture for positioning columns arrayed on a principal face thereof, on sites of an electronic substrate.

<CIT> discloses a cooling apparatus and method of fabrication for facilitating removal of heat from a heat generating electronic device.

The claimed subject-matter is defined in the independent claims.

According to aspects of the disclosure, methods and structures for providing thermal dissipating elements on integrated circuit ("IC") dies are disclosed. According to an aspect, thermal dissipating element placement assembly, such as a pin fin placement assembly, along with a vacuum pickup assembly, can be used to assist with simultaneous placement of multiple pin fins with desired profiles on desired locations of the IC die. The pin fin placement assembly may be comprised of one or more plates with a plurality of apertures therein for receiving the pin fins. The pin fin placement assembly can be further incorporated into a thermal cooling structure, which can include a manifold configured to encase the IC die and attached pin fins.

According to an aspect of the disclosure, an assembly for positioning a plurality of thermal dissipating elements on an integrated circuit ("IC") die comprises a thermal dissipating element placement assembly and a vacuum pickup assembly. The thermal dissipating element further comprises a plate body having a first plate and a second plate. The first plate has a first plurality of apertures extending through top and bottom surfaces of the first plate. The second plate may also have a second plurality of apertures extending through top and bottom surfaces of the second plate. Each of the second plurality of apertures may have a diameter that is different than a diameter of each of the first plurality of apertures. The second plurality of apertures may be aligned with the first plurality of apertures. The vacuum pickup assembly may be removably coupled to the thermal dissipating element placement assembly. The vacuum pickup assembly may provide a suction force that holds the plurality of thermal dissipating elements within the first or second plurality of apertures in the plate body and against a surface of the plate body.

According to another aspect of the disclosure, an assembly for positioning thermal dissipating elements on an integrated circuit ("IC") die comprises a thermal dissipating element placement assembly and a vacuum pickup assembly. The thermal dissipating element placement assembly may comprise a top plate, a middle plate, and a lower plate vertically assembled to form a plate body. The middle plate may be movable relative to the top plate and/or the lower plate. A first plurality of apertures may be formed in the top plate; and a second plurality of apertures may be formed in the lower plate. The first and the second plurality of apertures are vertically aligned. The first and the second plurality of apertures may be configured to receive the thermal dissipating elements therein. The thermal dissipating elements may be configured to be disposed on an IC die. The vacuum pickup assembly may be removably coupled to the thermal dissipating element placement assembly. The vacuum pickup assembly may be configured to hold the thermal dissipating elements against at least a portion of the plate body.

According to another aspect of the disclosure, an assembly comprises an integrated circuit ("IC"), a thermal dissipating element placement assembly, a plurality of thermal dissipating elements and a manifold. The IC die may be electrically connected to a printed circuit board ("PCB"). The thermal dissipating element placement assembly may be coupled to the PCB. The thermal dissipating element placement assembly may comprise a plate body having a top surface, a bottom surface, and a plurality of apertures extending through the top and bottom surfaces. The plurality of thermal dissipating elements may be disposed within the plurality of apertures and coupled to a surface of the IC die. The manifold may be coupled to the plate body and the IC die, the manifold configured to provide thermal dissipating of the IC die.

According to another aspect of the disclosure, a method for providing thermal dissipating elements on an integrated circuit ("IC") die comprises providing a thermal dissipating element placement assembly comprising at least one plate and a plurality of apertures extending through a top surface and a bottom surface of the at least one plate; using vacuum suction created by a vacuum pickup assembly to position and removably secure the thermal dissipating elements within the plurality of apertures; and joining the thermal dissipating elements positioned within the plurality of apertures with an IC die. While the thermal dissipating elements are positioned within the thermal dissipating element placement assembly, a bonding material disposed between the thermal dissipating elements and the IC die may be reflowed to bond the thermal dissipating elements to the IC die.

According to an aspect of the disclosure, a method for providing thermal dissipating elements on an integrated circuit ("IC") die comprises providing a pin fin placement assembly with a vacuum pickup assembly coupled thereto; using vacuum suction created by a vacuum pickup assembly to pull a plurality of pin fins into apertures of a first plate of the pin fin placement assembly; and laterally moving the second plate relative to the first and third plates to allow the plurality of pin fins in the apertures of the first plate to be positioned within apertures of the third plate. The pin fin placement assembly includes a first plate, a second plate, and a third plate. The plurality of pin fins may be supported within apertures of the first plate of the pin fin placement assembly by the second plate, which underlies the first plate. While the pin fins remain within apertures of the third plate, the pin fins may be positioned adjacent a rear surface of the IC die. A material disposed between the pin fins and the IC die may be reflowed to bond the pin fins to the IC die, thereby forming a plurality of thermal dissipating elements at the surface of the IC die.

A more complete appreciation of the subject matter of the present technology and the various advantages thereof may be realized by reference to the following detailed description which refers to the accompanying drawings, in which:.

The present disclosure relates to methods and structures for enhancing thermal dissipation of IC die assemblies. A thermal dissipation element placement assembly, such as a pin fin placement assembly, along with a vacuum pickup assembly, can be used to position a plurality of thermal dissipating elements on an IC die. In some examples, the pin placement assembly can further be incorporated into a thermal cooling structure, which can include a manifold sufficiently sized to encase the IC die and attached pin fins. The pin fin placement assembly may assist with placement of multiple pin fins with desired profiles on desired locations of the IC die. A vacuum pickup assembly can be concurrently used with the pin fin placement assembly to help with accurate alignment of the pin fins with connections on the IC die. The vacuum pickup assembly may provide a force that can secure the pin fins within plates of the pin fin placement assembly, which can aid in alignment of the pins prior to coupling of the pin fins with the IC die.

The thermal dissipation element placement assembly can include at least one plate with a plurality of apertures designed to secure a plurality of thermal dissipation elements or pin fins therein. A vacuum pickup assembly can include at least a vacuum pickup pump and a vacuum chamber. A suction force generated by the vacuum pickup pump can draw the plurality of pin fins into corresponding apertures in the at least one plate.

In an example where the placement assembly is comprised of a single plate, the plurality of apertures can have an upper portion and a lower portion with differing diameters. The suction force can draw the pin fins into each of the apertures, and in some examples, due to the differing diameters, the pin fins will be held in place within the apertures. While the pin fins remain in place within the pin fin assembly, the pin fins can be aligned with solder connections or the like on an IC die and then bonded to the IC die during a thermal process, such as reflow. In some examples, it may be desired to provide an additional thermal cooling structure to aid with dissipation of heat from the IC die and the surrounding environment. For example, a manifold may be provided to the rear surface of the plate and the plate of the pin fin assembly can be incorporated into the thermal cooling structure. Alternatively, the plate can be removed altogether, and a manifold may otherwise be used to encase the IC die.

In some examples, the placement assembly comprises two plates, an upper plate and a lower plate. The upper plate may include first apertures that are aligned with second apertures in the lower plate. The first apertures may have a diameter that is smaller than the diameter of the second apertures such that at least a portion of the bottom surface of the upper plate overlies the second apertures. Suction force from the vacuum pickup assembly can draw the pin fins into each of the plurality of second apertures, where they will be held against the bottom surface of the upper plate. While the pin fins remain in place within the pin fin assembly, the pin fins can be aligned with solder connections or the like on an IC die and then bonded to the IC die during a thermal process, such as reflow. An additional thermal cooling structure can also be provided to further aid with dissipation of heat from the IC die, as previously discussed.

In still other examples, the placement assembly may comprise three plates: an upper plate, a bottom plate, and a middle plate that is movable relative to the upper plate and the bottom plate. The upper plate can include a first plurality of apertures having a first diameter; the bottom plate can include a second plurality of apertures having a second diameter; and the middle plate can include a third plurality of apertures that have a third diameter. The first, second and third apertures may be aligned with one another, where the first and third diameters are sized to receive the size of pin fins, and the second diameter is smaller than the first and third diameters and need only be large enough to allow for air from the vacuum pickup pump to pass through the second plate. In this regard, the third diameter is smaller than the first diameter, which renders the third apertures incapable of receiving the pin fins therethrough. In this example, force from the vacuum pickup pump can draw pin fins into the first plurality of apertures. The pin fins will be held in place against the middle plate due to the differing diameters. When it is desired to position the pin fins on an IC die, the vacuum pickup assembly may be removed and the pin fins aligned with solder connections on the IC die. Movement of the middle plate in a lateral direction can cause the pin fins to drop down into the third plurality of apertures in the third plate and also the surface of the IC die. While the pins remain in the pin fin assembly, the IC die and pin fins may be reflowed to secure the pin fins to the IC die. An additional thermal cooling structure can also be provided to further aid with dissipation of heat from the IC die, as previously discussed. The pin fin assembly can remain a part of the additional thermal cooling structure or the pin fin assembly can be removed and a manifold positioned to overlie the IC die and attached pin fins. In another example, instead of three plates, a two plate structure may include the first and third plates as a single unitary plate, and the middle plate is movable relative to the single unitary plate.

<FIG> depicts a cross sectional-view of an IC package <NUM>, including an IC die <NUM> formed on a printed circuit board (PCB) <NUM>. Although the example depicted in <FIG> only illustrates one IC die <NUM> and one PCB <NUM>, in other examples, an IC package may include any number of IC dies, and any number of PCBs. Further, in other examples, in lieu of a PCB, any other substrates, including a removably and temporarily attached carrier substrate may be used in place of a PCB. Any number of IC dies, devices, or chip assemblies disposed within the IC package <NUM> may be utilized. In one example, the IC die <NUM> may be a graphics processing unit (GPU), custom application-specific integrated circuit (ASIC), memory devices, high-bandwidth memory (HBM) components, or any other type of device or stack. In one example, the IC die <NUM> is disposed on the PCB <NUM> through a plurality of solder balls <NUM> arranged in a ball grid array (BGA). Other arrangements and connectors may include contacts arranged in a land grid array (LGA), connector pins arranged in a pin grid array (PGA), etc. In other examples, the IC die <NUM> may be connected to the PCB through other conductive features capable of forming a conductive connection between the IC die <NUM> and the PCB <NUM>, such as conductive posts, conductive material, and the like.

In one example, thermal cooling of an IC die or other microelectronic elements or devices can be accomplished using thermal dissipating elements, such as pin fins <NUM>. Pin fins <NUM> may be coupled to an IC die, such as the rear surface of the IC die, alone or in combination with a surrounding manifold <NUM> utilized to encase the IC die <NUM>.

A plurality of thermal dissipating elements <NUM> may be disposed at a first surface <NUM> of the IC die <NUM> that may assist in dissipating thermal energy from the IC die <NUM> when IC die <NUM> is in operation. In one example, the plurality of thermal dissipating elements <NUM> may be disposed at the rear surface <NUM> of the IC die <NUM> by soldering, or any other suitable process of coupling the thermal dissipating elements <NUM> to the IC die <NUM>. A second surface <NUM> is formed substantially in parallel and opposite to the first surface <NUM> where a plurality of bond pads or device structures <NUM> may be disposed. A metallization layer <NUM> may be formed at the rear surface <NUM> of the IC die <NUM> to facilitate soldering the plurality of thermal dissipating elements <NUM> thereon. In one example, the metallization layer <NUM> may be manufactured from a conductive material, such as copper, aluminum, tungsten, nickel, silver, iron, combinations thereof, alloys thereof, or the like.

In one example, each of the thermal dissipating elements <NUM> may include a plurality of pin fins <NUM> coupled to the IC die <NUM>. The pin fin <NUM> may be disposed at the IC die <NUM> using a conductive material, such as a solder connection <NUM>, which can include solder paste, solder foil, solder bumps, or the like. Other thermally conductive materials can also be utilized. The solder connections <NUM> may secure the pin fins <NUM> to the first surface <NUM> of the IC die <NUM> once soldered. In one example, the pin fin <NUM> may be manufactured from a metallic material possessing thermal dissipation or thermal transmission efficiency. Examples of metallic materials that may be selected to manufacture the pin fin <NUM> include copper, aluminum, tungsten, gold, silver, combinations thereof, alloys thereof, or the like. In one example, the pin fin <NUM> may have an aspect ratio, such as a height to diameter ratio, between about <NUM>:<NUM> and <NUM>:<NUM>, such as about <NUM>:<NUM> or <NUM>:<NUM>.

The thermal dissipating elements <NUM> can take on different forms and be arranged on the IC die in various configurations. The thermal dissipating features <NUM> may include, for example, pin fins <NUM> disposed at the rear surface <NUM> of the IC die <NUM> in one or more arrays or matrices. In one example, the plurality of pin fins <NUM> may have a pitch between about <NUM> and about <NUM>, such as between about <NUM> and about <NUM>, such as about <NUM>. In other examples, the pitch may be less than <NUM> or greater than <NUM>. In still other examples, the pitch may be greater than <NUM> or less than <NUM>.

An optional manifold <NUM> may also be coupled to the IC die to further enhance thermal cooling of the IC die. In this example, manifold <NUM> may be coupled to IC die and PCB using known materials or structures. In one example, manifold <NUM> is attached to IC die using an adhesive material <NUM>. The adhesive material <NUM> provides a sealing interface between the manifold <NUM> and the PCB <NUM>. The manifold <NUM> may include a first sidewall <NUM> and a second sidewall <NUM> connected by a ceiling <NUM>, forming a substantially U-shaped body <NUM> that defines a central cavity <NUM> on a bottom side of the manifold <NUM>. The central cavity <NUM> encases IC die <NUM> when the manifold <NUM> is placed or mounted on the PCB <NUM>. A sealing member <NUM> may be utilized to seal the interface where the manifold <NUM> is in contact with the IC die <NUM>. In one example, the sealing member <NUM> may be an adhesive material, an O ring, or suitable mechanical attachments that facilitate positioning and securement of the manifold <NUM> to the IC die <NUM>. A plenum <NUM> may be defined in the ceiling <NUM> of the manifold <NUM>. The plenum <NUM> may allow a cooling medium, including a fluid, air, liquid, or other such cooling material to be introduced therein for temperature control purposes to the IC die <NUM>. The manifold may be comprised of various materials, and in some examples, thermally conductive materials. Aluminum, carbon steel, stainless steel, brass, alloys, and/or plastic compounds are examples of materials that may comprise a manifold.

When in operation, fluid may be supplied from an inlet <NUM> to circulate throughout the plenum <NUM> to an outlet <NUM>. In one example, the number and configuration of inlets and outlets can vary, such as an inlet disposed between two outlets, two inlets and two outlets, etc. The fluid as supplied may include liquid, air, or other suitable cooling mediums that may efficiently reduce the temperature of the IC die <NUM> with which the cooling medium is in direct contact. The thermal dissipating elements <NUM>, such as the pin fins <NUM>, may increase contact surface area when the fluid is in circulation in the plenum <NUM>. The increased contact surface area provided may enhance the cooling performance.

<FIG> depict cross-sectional views of an IC package assembly during different stages of coupling the pin fins <NUM> to the IC die <NUM> of <FIG>, as well as the optional addition of a manifold for use with the IC die <NUM> during liquid cooling. In <FIG>, the IC die <NUM> is attached to the PCB <NUM> using an array of solder ball connections <NUM>. After the IC die <NUM> is soldered, a metallization layer <NUM> may be disposed or otherwise disposed at the rear surface <NUM> of the IC die <NUM>, as shown in <FIG>. In some examples, the metallization layer <NUM> may be disposed or otherwise formed at the rear surface <NUM> of the IC die <NUM> prior to the soldering of the IC die <NUM> to the PCB <NUM>. For example, the metallization layer <NUM> may be deposited or formed on the IC die <NUM> as part of the manufacturing steps fulfilled by the IC manufacturing facilities prior to shipping to the IC packaging facility to be soldered on the PCB <NUM>.

A plurality of the solder connections <NUM> may be deposited on the rear surface <NUM> of the IC die <NUM>, such as shown in <FIG>. Various processes for depositing solder connections <NUM> onto the surface of the IC die means may be utilized, such as printing, sputtering, or other deposition methods. Solder connections <NUM> may facilitate attachment of the pin fins <NUM> to the surface <NUM> of the IC die <NUM> for temperature control when in operation. In other examples, different materials may be used to attach the pin fins to the <NUM> IC die, such as gold, copper, electrically conductive adhesives, silver-infused high-temperature epoxy, or other means or materials for attaching the pin fins <NUM> to the IC die <NUM>.

A thermal dissipating element placement assembly may be used to position and secure thermal dissipating elements to the IC die <NUM>. In one example, as shown in <FIG> an example pin fin placement assembly <NUM> may be utilized to arrange the pin fins <NUM> onto the IC die <NUM>, and in this example directly onto solder connections <NUM> (<FIG>). In one example, the pin fin placement assembly <NUM> includes a top plate <NUM>, a middle plate <NUM>, and a bottom plate <NUM> vertically assembled to collectively form a plate body <NUM>. The middle plate <NUM> may be laterally moveable relative to the top plate <NUM> and the bottom plate <NUM>. The plates may be comprised of various materials, including, but not limited to, stainless steel, copper, and plastic. Apertures <NUM> in the top plate <NUM> align with apertures <NUM> on the bottom plate <NUM>, as well as apertures <NUM> on the middle plate <NUM>. The apertures <NUM>, <NUM>, and <NUM> are configured to allow for the passage of the pin fins <NUM> and air therethrough, as discussed in further detail herein.

The plate body <NUM> may be disposed on one or more supporting posts <NUM>. The supporting posts <NUM> may serve as tooling or alignment pins that will later be placed into alignment holes (not visible in <FIG>) formed in the PCB <NUM>, when the pin fin placement assembly <NUM> is aligned with PCB <NUM>. During this early stage of the manufacturing process, the supporting posts <NUM> may be free-standing and capable of being operational on any available surface. In other examples, the posts <NUM> may be removably attached or interconnected with a temporary carrier, such as a platform, another printed circuit board, or the like.

The pin fins <NUM> that will later be coupled with the IC die <NUM> may be pre-manufactured metallic structures with desired profiles and configurations. For example, the pin fins <NUM> may be pre-manufactured metallic structures with desired aspect ratios, such as a particular diameter to height ratio. The profile may be adjusted such that the pin fins <NUM>, when attached to the IC die <NUM>, adequately dispatch heat generated by the IC die to the cooling material.

The dimensions, distributions, and the numbers of the apertures <NUM> formed in the top plate <NUM> may be configured to accommodate the dimensions of the pin fins <NUM>. In one example, the dimensions, distributions, and the numbers of the pin fins <NUM> may be determined based on the amount of thermal energy needed to be dispatched from the IC die <NUM> where the pin fins <NUM> are mounted. For example, when a higher thermal flux of thermal energy is desired to be dispatched from the IC die <NUM>, higher numbers or higher placement density of the pin fins <NUM> may be configured to be formed on the IC die <NUM>. In other examples, the dimensions, distributions, profiles, and the numbers of the pin fins <NUM> may be configured in any manner.

A vacuum pick up assembly may be attached to the pin fin placement assembly <NUM> to assist with positioning the pin fins <NUM> within the apertures <NUM>. An example vacuum pickup assembly <NUM> is schematically illustrated in <FIG> and can include at least a vacuum pickup pump <NUM>, a vacuum chamber <NUM>, and an optional vacuum pressure gauge <NUM>. In some examples, the components may be coupled to the bottom surface <NUM> of the bottom plate <NUM>, but in other examples, one or more of the components may be positioned elsewhere relative to the pin fin placement assembly <NUM>. In operation, the vacuum pickup pump <NUM> creates a suction force F that can help to draw the pin fins <NUM> into the apertures <NUM>.

To position a pin fin <NUM> within the apertures <NUM> in top plate <NUM>, the vacuum pickup pump <NUM> creates a suction force F that can help to draw the pin fins <NUM> into the apertures <NUM>. For example, a plurality of pin fins <NUM> may be poured in a direction toward the apertures <NUM> of the top plate <NUM>. Apertures <NUM> in the bottom plate <NUM> also serve as vent apertures that will allow the vacuum pickup pump <NUM> to draw air. Suction force F from the vacuum pickup assembly <NUM> can help to draw or pull fin pins <NUM> into each of the apertures <NUM>. In some examples, additional mechanisms or procedures can be utilized in connection with the vacuum pickup pump assembly <NUM> to help drive the pin fins <NUM> into the apertures <NUM> of the top plate <NUM>. Ultrasonic vibrations, mechanical movements, mechanical vibrations, or a brush are nonlimiting examples of such additional mechanisms or procedures. Once the pin fins <NUM> are placed and filled in the apertures <NUM> of the top plate <NUM>, redundant pin fins <NUM> may be removed from the top plate <NUM>.

At least a portion of the middle plate <NUM> may extend into the apertures <NUM> to temporarily hold or secure the pin fins <NUM> in place within the apertures <NUM>. For example, the size of the apertures <NUM> in the middle plate <NUM> may be smaller than the size of the apertures <NUM> in the top plate <NUM> so as to form a supporting edge or lip <NUM> that supports at least a portion of the bottom surface <NUM> of the pin fins <NUM> and prevents the pin fins <NUM> from prematurely moving into the apertures <NUM> of the bottom plate <NUM>.

A vacuum pickup gauge and/or pressure sensor can be implemented within the system to help determine when each of the apertures <NUM> within the top plate <NUM> are filled with pin fins <NUM>, as shown in <FIG>. For example, the vacuum pressure when all of the apertures <NUM> are filled with pin fins <NUM> can be pre-determined. A vacuum pickup gauge <NUM> can be used to monitor the vacuum pickup pressure during positioning of the pin fins <NUM> within the apertures. Once the pre-determined vacuum pickup pressure of the vacuum chamber <NUM> has been achieved, this signifies that each of the apertures <NUM> in the top plate <NUM> retain a pin fin <NUM> therein. This can notify the operator of the system that this stage of the manufacturing process is complete. In some examples, sensors can additionally be used to determine when all of the pin fins <NUM> are positioned within the top plate <NUM> and automatically turn off the vacuum pickup assembly <NUM>.

The vacuum pickup assembly <NUM> can be detached or removed from the pin fin placement assembly <NUM>, as shown in <FIG>. The pin fin placement assembly <NUM> will be coupled to the PCB <NUM> and IC die <NUM> (<FIG>) to position and secure the pin fins <NUM> to the IC die <NUM>. In this example, the apertures <NUM> of the top plate <NUM>, the apertures <NUM> of the middle plate <NUM>, and the apertures <NUM> of the bottom plate <NUM> are aligned with one another, as well as the solder connections <NUM> disposed at the IC die <NUM>.

As shown in <FIG>, the middle plate <NUM> is laterally movable relative to the top and bottom plates <NUM>, <NUM>, and in this example can be pulled out in a lateral direction, such as the direction shown by arrow A1. Once the middle plate <NUM> is pulled, the pin fins <NUM> in the top plate <NUM> without the support from the middle plate <NUM> drop down into the apertures <NUM> formed in the bottom plate <NUM>. The vertical alignment of the apertures <NUM> in the bottom plate <NUM> with the apertures <NUM> formed in the top plate <NUM> allow the pin fins <NUM> to be dropped down to a desired position on the IC die <NUM>. In one example, the pin fins <NUM> are configured to be dropped down to the corresponding solder connection <NUM> on the IC die <NUM>. Thus, when the middle plate <NUM> is laterally pulled, the pin fins <NUM> may be dropped down directly onto the corresponding solder connection <NUM>.

The top plate <NUM> and middle plate <NUM> may be dissembled and removed from the pin fin placement assembly <NUM>. As shown in <FIG>, the remaining portions of the pin fin placement assembly <NUM>, including the bottom plate <NUM> and supporting pins <NUM>, along with IC die <NUM> form an in-process thermal assembly <NUM> that will undergo thermal treatment processing. In one example, the in-process thermal assembly <NUM> is placed into a reflow oven, along with PCB <NUM>. Removal of the top plate <NUM> and/or the middle plate <NUM> removed from the pin fin placement assembly <NUM> may reduce the thermal mass during the subsequent thermal treatment process. In other examples, the top plate <NUM> and the middle plate <NUM> may remain during the subsequent thermal treatment process. Similarly, in an example where the top plate <NUM> and bottom plate <NUM> are formed as a single plate, such plate may remain during reflow.

The thermal treatment process may provide thermal energy to adhere the pin fins <NUM> onto the solder connection <NUM> with sufficient and desired adhesion. As illustrated in <FIG>, the bottom plate <NUM> can remain in place during the thermal treatment process to hold the pin fins <NUM> in place and at desired locations over the rear of the IC die <NUM> during the reflow process. The holding and support from the bottom plate <NUM> during the thermal treatment process may assist with joinder of pin fins <NUM> to the solder connections <NUM> or on the metallization layer <NUM> with desired integrity and profile without undesired collapse and deterioration. Additionally, bottom plate <NUM> can also maintain the pins in place while the solder connections <NUM> are cured. It is to be appreciated that although not shown in the figures and as known in the art, due to the inherent properties of the reflowed solder connections <NUM>, solder may also be positioned adjacent the edges <NUM> of pin fins <NUM> to help further secure the pin fins <NUM> to IC die <NUM>.

The pin fin placement assembly <NUM> may be removed from the PCB <NUM>, as shown in <FIG>. At this stage, the IC die <NUM> with thermal dissipating elements <NUM> can be considered complete. If desired, additional or optional processing may take place. In one example, additional thermally conductive features are provided to enhance thermal cooling of the IC die, as discussed below.

In <FIG>, a thermal cooling structure <NUM>, which in this example comprises manifold <NUM>, may be disposed on the PCB <NUM> and IC die <NUM>. Manifold <NUM> may be attached to a surface of the PCB <NUM> using an adhesive material <NUM>. A sealing interface <NUM> may be used to join manifold <NUM> to IC die <NUM>, as previously discussed herein. The manifold <NUM> may be positioned in a manner that allows the central cavity <NUM> of the manifold <NUM> to encase the IC die <NUM> therein while allowing the plurality of thermal dissipating elements <NUM> to be encased in the plenum <NUM>. The height of the thermal dissipating elements <NUM> may be controlled in a manner so that a top <NUM> of the thermal dissipating elements <NUM> may be maintained spaced apart from a bottom surface <NUM> of the center portion <NUM> of the ceiling <NUM>. In other examples, different configurations of the thermal dissipating elements <NUM> may be utilized to enhance thermal energy circulation and thermal dissipation efficiency. Once the manifold <NUM> is coupled with the PCB <NUM> and IC die <NUM>, the installation of the manifold <NUM>, is then considered completed.

In <FIG>, once the manifold <NUM> is in place, cooling material may be supplied to the plenum <NUM> to facilitate temperature control of the IC die <NUM>. As shown, cooling material, as previously discussed herein, may flow through inlet <NUM>, into plenum <NUM> and through the plurality of thermal dissipating elements <NUM> disposed on the IC die <NUM>, and finally out of the manifold <NUM> through the outlet <NUM>.

As the numbers, profiles, and distributions of the pin fins <NUM> formed on the IC die <NUM> may include different configurations and requirements, a pre-manufactured pattern provided from the pin fin placement assembly <NUM> may assist in placing the pin fins <NUM> on the IC die efficiently and precisely. For example, in conventional manners, individually placing the pin fins <NUM> on the IC die often results in inaccurate alignment, time consuming, and positional errors during the process of the placement. By utilizing the pin fin placement assembly <NUM>, the desired patterns, distributions, profiles and configurations of the pin fins <NUM> may be pre-molded and formed in the top and bottom plates of the pin fin placement assembly <NUM>. Thus, once the pin fins are driven and placed into the apertures formed in the pin fin placement assembly <NUM>, the pin fins are ready to be positioned and bonded to the IC die with the desired distribution and patterns, thus providing a time-efficient and precise placement of the pin fins on the IC die with minimum errors. Thus, the pin fin placement assembly enables large amounts of pin fins, such as tens of thousands or more, to be simultaneously placed on the IC die, instead of being individually placed, positioned, and coupled to the IC die.

Although <FIG> are shown as being one continuous process, it is to be appreciated that different vendors can perform different parts of the assembly process, or different aspects of the assembly process can take place at difference times, such that not all of the processes disclosed in <FIG> needs to take place at the same time. For example, <FIG> disclose preparation of a chip assembly <NUM> and one or more of <FIG> may be prepared by one manufacturer. The placement of pin fins <NUM> onto the IC die, such as disclosed in <FIG> may be performed by the same or another manufacturer. And further thermal processing to add the manifold can be performed by a same or different manufacturer.

<FIG> depict enlarged cross-sectional views of another example pin fin placement assembly <NUM> with an attached vacuum pickup assembly <NUM> that can be used to position pin fins <NUM> on an IC die (<FIG>). As shown in <FIG>, pin fin placement assembly <NUM> includes a top plate <NUM>, a middle plate <NUM>, a bottom plate <NUM>, and supports, such as tooling pins <NUM>. The combination of the top plate <NUM>, middle plate <NUM>, and the bottom plate <NUM> form a plate body <NUM>. The pin fin placement assembly <NUM> is similar to the prior version and differs due to the configuration of the middle plate <NUM>, and particularly the addition of vent apertures 354A in the middle plate <NUM>, along with the apertures <NUM> that are sized to receive the pin fins <NUM> therethrough. Middle plate <NUM> may be movable relative to the top plate <NUM> and/or the bottom plate <NUM>, and in this example is laterally movable relative to the top plate <NUM> and bottom plate <NUM>.

During the initial stages of assembly, middle plate <NUM> will be used to support pin fins <NUM>, while pin fins <NUM> are positioned within the apertures <NUM> of top plate <NUM>. As shown in <FIG>, vent apertures 354A are initially aligned with the apertures <NUM> of the top plate <NUM> and the apertures <NUM> of the bottom plate <NUM>. The vent apertures 354A of middle plate <NUM> are significantly smaller than the pin fins <NUM>, which allows for the pin fins <NUM> to be supported by the middle plate <NUM> when the vent apertures 354A are aligned with the apertures <NUM> in top plate <NUM>. The vent apertures 354A provide an air passageway that allows for suction from the vacuum pickup assembly <NUM> to draw the pin fins <NUM> into the apertures <NUM> of the top plate <NUM>. When the vent apertures 354A are aligned with the apertures <NUM> of the top plate <NUM> and apertures <NUM> of the bottom plate <NUM>, the larger apertures <NUM> in the middle plate <NUM> will be offset from the apertures <NUM>, <NUM> in the top and bottom plates <NUM>,<NUM>. (See <FIG>.

As shown in <FIG>, the vacuum pickup assembly <NUM> can help to draw or pull the pin fins <NUM> into the pin fin assembly <NUM>. The vacuum pickup assembly <NUM> can include similar components as described herein, including a vacuum pickup pump <NUM> which can create a suction force, vacuum chamber <NUM>, and vacuum pressure gauge <NUM>. Each of the pin fins <NUM> can be pulled into the apertures <NUM> by vacuum suction created by the vacuum pickup assembly <NUM>, and in this example vacuum pickup pump <NUM>. As in the previous example, once the pin fins <NUM> are positioned within the apertures <NUM> of the top plate <NUM>, the vacuum pickup assembly <NUM> can be removed.

The pin fin placement assembly may overlie IC die <NUM> with solder connections <NUM>. Apertures <NUM> in bottom plate <NUM> may be aligned with solder connections <NUM>, as shown in <FIG>. Middle plate <NUM> may be moved laterally relative to the top plate <NUM> and bottom plate <NUM>. In the example shown in <FIG>, the middle plate <NUM> only needs to be slightly moved or shifted to allow for the pin fins <NUM> to drop therethrough. In this example, the middle plate <NUM> is slightly moved to the right in the direction of arrow A2, so that the apertures <NUM> within middle plate <NUM> are aligned with apertures <NUM> of the top plate <NUM> and apertures <NUM> of the bottom plate <NUM>. In other examples, the middle plate <NUM> may be moved in a direction opposite to the arrow A2 in order to align apertures <NUM> in the middle plate <NUM> with apertures <NUM> and <NUM>. Lateral movement of middle plate <NUM> causes the vent apertures 354A to be offset from the apertures <NUM> of the top plate <NUM> and apertures <NUM> of the bottom plate <NUM>. Larger apertures <NUM> in middle plate <NUM> will then be aligned with apertures <NUM> of the top plate and apertures <NUM> of the bottom plate, such that the middle plate <NUM> no longer supports the pin fins <NUM>. Pin fins <NUM> within the top plate <NUM> may then drop down into apertures <NUM> of the bottom plate <NUM> and contact the solder connection <NUM> formed on the IC die <NUM>, while still being held in place within the pin fin assembly <NUM>, and in this example, the apertures <NUM> of bottom plate <NUM>.

Once the pin fins <NUM> are aligned with solder connections <NUM>, the top plate <NUM> and middle plate <NUM> can be removed from the pin-fin placement assembly <NUM>. As shown in <FIG>, the remaining portions of the pin fin assembly, which in this example includes bottom plate <NUM> and supports <NUM>, along with IC die <NUM> with overlying pin fins <NUM>, solder connections <NUM>, solder balls <NUM> and PCB <NUM> form an in-process thermal unit <NUM>, that can undergo further thermal processing. For example, the in-process thermal assembly <NUM>, may be placed into a reflow oven to undergo the reflow process, as previously described herein. During the reflow process, the pin fins <NUM> will be retained in place within apertures <NUM> of bottom plate <NUM>. Upon completion of thermal processing, pin fins <NUM> will be secured to IC die <NUM>, and in this example, soldered and disposed on a rear surface <NUM> of IC die <NUM>. This configuration therefore allows for slight lateral movement of the middle plate <NUM>, instead of requiring that an end of the middle plate <NUM> is pulled out relative to the top and bottom plates <NUM>, <NUM>, as depicted in the examples of <FIG>. By such configuration, a relatively small apparatus footprint and small operational space are required.

With reference to <NUM>, at the conclusion of thermal processing, the pin fin assembly <NUM> may be removed, so as to leave behind an IC die package <NUM>. As shown, the IC die package <NUM> includes IC die <NUM>, thermal dissipating elements <NUM> bonded to the IC die <NUM>, a printed circuit board <NUM>. The IC Die package may be further processed. For example, as shown in <FIG>, additional thermal processing may take place. A thermal cooling structure <NUM>, which in this example comprises manifold <NUM>, as previously described herein, may be coupled to the IC die <NUM> so as to encase the IC die <NUM>, as shown in <FIG> and described herein. In other examples, instead of the thermal processing shown in in <FIG>, the chip package <NUM> can be provided for distribution to a third party who may implement additional thermal or other processes specific to or compatible with systems of the third party.

<FIG> depict cross-sectional view of another example of the pin fin placement assembly <NUM> with a vacuum pickup assembly. This configuration differs from the previous examples of <FIG> and <FIG>, to the extent that vacuum pickup suction is used to pull the pin fins <NUM> upwards into the pin fin placement assembly <NUM>, instead of vacuum suction pulling the pin fins <NUM> downward into the pin fin placement assembly <NUM>. As shown in <FIG>, pin fin placement assembly <NUM> includes a top plate <NUM>, a bottom plate <NUM>, and pin fin assembly frame supports <NUM>. The top plate <NUM> includes a top surface <NUM>, a bottom surface <NUM> and a plurality of apertures <NUM> extending through the top and bottom surfaces <NUM>, <NUM>. Similarly, bottom plate <NUM> includes a top surface <NUM>, a bottom surface <NUM> and plurality of apertures <NUM> extending through top and bottom surfaces <NUM>, <NUM>. The plates of the pin fin placement assembly (including top plate <NUM> and bottom plate <NUM>) may be comprised of various materials, including, without limitation, stainless steel, Cu, plastic, and the like.

The attached vacuum pickup assembly <NUM> may include a vacuum pickup pump <NUM>, a vacuum chamber <NUM>, and a vacuum pressure gauge <NUM>. Additionally, a pin fin receptacle <NUM> may be attached to the pin fin placement assembly <NUM>. Cooling chamber supports <NUM> may be coupled to a bottom surface <NUM> of the bottom plate <NUM>. As will be discussed in more detail herein, cooling chamber supports <NUM> can be used to provide sidewalls that create a plenum between the IC die and the bottom plate <NUM>. In some examples, cooling chamber supports <NUM> can be comprised of a thermally conductive material, and in some examples may be the same material that will comprise the manifold <NUM>. (See <FIG>. ) In other examples, the cooling chamber supports <NUM> may be separately formed and coupled to the bottom plate at a later stage. Alternatively, the cooling chamber supports <NUM> can be provided at the IC die and later coupled to the pin fin placement assembly <NUM>. In another example, the cooling chamber supports <NUM> can be comprised of one or more sealing elements, such as, but not limited to, an O-ring.

The top plate <NUM> and the bottom plate <NUM> may collectively form the plate body <NUM>. As shown, apertures <NUM> in the top plate <NUM> align with apertures <NUM> in the bottom plate <NUM>. At least some of the apertures <NUM> in the top plate <NUM> may have a diameter or length L1 that is smaller or less than the diameter or length L2 of the aperture <NUM> in the bottom plate <NUM>. In this example, all of the apertures <NUM> may have a diameter or length L1 that is smaller than the diameter of the aperture <NUM> on the bottom plate <NUM>. As shown, bottom surfaces <NUM> of top plate <NUM> will extend partially across apertures <NUM> in bottom plate <NUM>. The arrangement of the smaller apertures <NUM> in the top plate <NUM> allows the vacuum pickup assembly <NUM> to draw air, while securing pin fins <NUM> within the apertures <NUM> of bottom plate <NUM>.

In some pin fin placement assembly <NUM> configurations, the plate body <NUM> may further include a liquid cooling inlet <NUM>, as well as a liquid cooling outlet <NUM> that will allow for cooling liquid to pass therethrough, as discussed in more detail below. The liquid cooling inlet <NUM> may be formed by alignment of at least one aperture <NUM> in top plate <NUM> and one aperture <NUM> in bottom plate <NUM>, and the liquid cooling outlet <NUM> may be formed by alignment of an aperture <NUM> in top plate <NUM> and an aperture <NUM> in bottom plate <NUM>. The liquid cooling inlet <NUM> and liquid cooling outlet <NUM> may be positioned in an area that is outside of the vacuum pickup chamber <NUM>. In this example, the liquid cooling inlet <NUM> and liquid cooling outlet <NUM> are positioned outside of the vacuum chamber <NUM> and pin fin receptacle <NUM>, such that the liquid cooling inlet <NUM> and liquid cooling outlet <NUM> will not be used to retain any pin fins <NUM> therein. It is to be appreciated that in other examples where the pin fin placement assembly will not be incorporated into a final thermal cooling structure, such as thermal cooling structures subsequently discussed with regard to <FIG> and <FIG>, a liquid cooling inlet <NUM> and liquid cooling outlet <NUM> can be omitted from the plate body <NUM> of the pin fin assembly <NUM>, if desired.

A plurality of pin fins can be provided or available for use with pin fin placement assembly. For example, a pin fin receptacle <NUM> that houses multiple pin fins <NUM> may be attached to the pin fin placement assembly <NUM>. In some examples, the pin fins <NUM> are not arranged in any specific configurations and are loosely held within the pin fin receptacle <NUM>. In other examples, the pin fins may be pre-aligned with apertures <NUM> and placed into an upright position. The pin fins <NUM> can be comprised of any material that can thermally conduct heat away from the IC die <NUM>. Examples of materials forming the plurality of pin fins <NUM> include copper, aluminum, tungsten, gold, silver, combinations thereof, or alloys thereof. A vacuum pickup chamber <NUM> can overlie top plate <NUM>.

As shown in <FIG>, when the vacuum chamber assembly is operating, vacuum pickup suction will cause the pin fins <NUM> to move upwards into the apertures <NUM> of bottom plate <NUM>. As shown, pin fins <NUM> will be releasably secured within apertures <NUM> of bottom plate <NUM> due to the force F of the vacuum pickup suction. The top surfaces <NUM> of the pin fins <NUM> within apertures <NUM> will be held against the bottom surface <NUM> of top plate <NUM>. The portions of the bottom surface <NUM> of top plate <NUM> that overlies apertures <NUM> of the bottom plate <NUM> will prevent pin fins <NUM> from being pulled into aperture <NUM> of top plate <NUM> and into vacuum pickup chamber <NUM>.

While the pin fins <NUM> are secured within the plate body <NUM>, the pin fin receptacle <NUM> may be removed, as shown in <FIG>. Vacuum suction from the vacuum pickup assembly <NUM> will continue to hold the pin fins <NUM> within apertures <NUM> of bottom plate <NUM>, while further processing takes place. The pin fins <NUM> may then be joined to another microelectronic device or assembly. In one example, pin fins <NUM> may be coupled to IC die <NUM> and PCB <NUM>, as shown for example in <FIG> and discussed with regard to <FIG>. Pin fins <NUM> may be aligned with solder connections <NUM>, as the IC die <NUM> and PCB <NUM> are joined to bottom plate <NUM>. While the solder connections <NUM> are in the process of being aligned with the pin fins <NUM>, the vacuum pickup assembly <NUM> will remain active and secure the pin fins <NUM> within the plate body <NUM>, and in this example, apertures <NUM> of bottom plate <NUM>. Cooling chamber supports <NUM> may also be coupled to IC die <NUM>, and in this example, chamber supports <NUM> are attached to the rear surface <NUM> of IC die. This creates an enclosed interior cavity <NUM> between the bottom surface <NUM> of bottom plate <NUM> and the rear surface <NUM> of IC die <NUM>. As will be discussed below, cooling chamber supports <NUM> can additionally create a plenum through which cooling material may pass through.

The vacuum pickup assembly <NUM> may be removed, along with the top plate <NUM>, once pin fins <NUM> are aligned with solder connections <NUM>. As shown in <FIG>, the remaining portions of pin fin placement assembly <NUM>, which in this example includes the bottom plate <NUM> and supports <NUM>, along with the IC die <NUM> and PCB <NUM>, form an in-process thermal assembly <NUM>, as shown in <FIG>. The in-process thermal assembly <NUM> may be subjected to further thermal processing. In this example, in-process thermal assembly <NUM> may be reflowed to secure pin fins <NUM> to IC die <NUM> through solder connections <NUM>. Since the pin fins <NUM> remain in place within the remaining structure of the pin fin placement assembly <NUM>, and in this example, within the apertures <NUM> of bottom plate <NUM>, proper alignment of each of the pin fins <NUM> to the solder connections <NUM> can be maintained throughout the reflow and curing process. IC die <NUM> can be further secured to the PCB <NUM> through reflow of solder balls <NUM>.

After reflow, further processing to enhance thermal dissipation of IC die <NUM> may be implemented. For example, as shown in <FIG>, a manifold <NUM> may be joined to the rear surface <NUM> of bottom plate <NUM>. An adhesive material or other mechanism (e.g., screws) or material for securing manifold <NUM> to the bottom plate <NUM> can be utilized. Manifold <NUM> further overlies the top surfaces <NUM> of the plurality of thermal dissipating elements <NUM>, such as pins <NUM>, so that the top portions <NUM> of the plurality of thermal dissipating elements <NUM> will be encased and only a lower portion <NUM> of each of the plurality of thermal dissipating elements <NUM> will be exposed. In other examples, different configurations of the thermal dissipating elements <NUM> may be utilized to enhance thermal energy circulation and thermal dissipation efficiency.

Once the manifold <NUM> is coupled to the PCB <NUM> and IC die <NUM>, the installation of the manifold <NUM>, bottom plate <NUM>, and the thermal dissipating elements <NUM> is then considered completed. As shown, a plenum <NUM> is created within the space or cavity <NUM> formed between bottom plate <NUM> and bottom surface <NUM> of IC die <NUM> such that fluid may travel through a manifold inlet <NUM>, through the plenum <NUM> and pin fins <NUM>, and through manifold outlet <NUM>, so as to facilitate temperature control and cooling of the IC die <NUM>. In this example, the manifold <NUM>, bottom plate <NUM>, and cooling chamber supports <NUM> collectively form a thermal cooling structure <NUM> that can maintain the pin fins <NUM> in place and prevent liquid coolant pressure from breaking the solder joints. The cooling structure <NUM> may remain in place during liquid cooling and throughout the life of the IC die <NUM>.

<FIG> depict cross-sectional views of another example of the pin fin placement assembly <NUM> with an example vacuum pickup assembly. This configuration differs from the previous example described in <FIG> to the extent that not all of the openings in the top plate <NUM> are aligned with openings in the bottom plate <NUM>, which in some examples, allows for a different distribution of liquid coolant across and around pin fins <NUM>. Referring to <FIG>, in this example, pin fin placement assembly <NUM> includes a top plate <NUM>, a bottom plate <NUM>, and pin fin assembly frame supports <NUM>. The top plate <NUM> includes a top surface <NUM>, a bottom surface <NUM> and a plurality of apertures 550A, 550B, 550C, 550D, 550E, 550F (collectively "top plate apertures <NUM>") extending through the top and bottom surfaces <NUM>, <NUM>. Similarly, bottom plate <NUM> includes a top surface <NUM>, a bottom surface <NUM> and plurality of apertures 552A, 552B, 552C, 552D, 552E, 552F, <NUM>, <NUM> (collectively "bottom plate apertures <NUM>") extending through top and bottom surfaces <NUM>,<NUM>. A pin fin receptacle <NUM> may be attached to the bottom plate <NUM> and a vacuum pump assembly <NUM> may be attached to the top plate <NUM>. The top plate <NUM> and the bottom plate <NUM> may collectively form the plate body <NUM>. Additionally, cooling chamber supports <NUM> may be coupled to a bottom surface <NUM> of bottom plate <NUM>. The vacuum pickup assembly <NUM> may include a vacuum pickup pump <NUM>, a vacuum chamber <NUM>, and a vacuum pressure gauge <NUM>, but additional components or alternative components may also be included.

While in some examples all of the top plate apertures <NUM> may be aligned with bottom plate aperture <NUM>, in other examples fewer than all of the top plate apertures <NUM> may be aligned with the bottom plate apertures <NUM>. Apertures 550A, 550B, 550C, 550D, 550E, 550F in the top plate align with respective apertures 552A, 552B, 552D, 552F, <NUM>, <NUM>. None of the top plate apertures <NUM> correspond to apertures 552C, 552E in the bottom plate. Rather, a bottom surface <NUM> of top plate <NUM> completely covers or overlies apertures 552C and 552E in bottom plate <NUM>, such that vacuum suction will be unable to draw pin fins <NUM> up into the apertures 552C and 552E. Aperture 550A in the top plate <NUM> and aperture 552A in the bottom plate <NUM> collectively form a liquid cooling inlet <NUM>, and apertures 550F in the top plate and <NUM> in the bottom plate collectively form a liquid cooling outlet <NUM>.

All of the top plate apertures <NUM> may be smaller than the bottom plate <NUM> apertures <NUM>. For example, apertures that are positioned within the vacuum chamber <NUM>, such as apertures 550B, 550C, 550D, 550E, may have a length L3 that is smaller than the length L4 of corresponding apertures 552B, 552D, 552F and <NUM> in the bottom plate <NUM>. As shown, bottom surfaces <NUM> of the top plate adjacent apertures 550B, 550C, 550D, and 550E in top plate <NUM> will extend partially across apertures 552B, 552D, 552F and <NUM> in bottom plate <NUM>. The arrangement of the smaller apertures 550B, 550C, 550D, and 550E in the top plate <NUM> allows the vacuum pickup assembly <NUM> to draw air and secure pin fins <NUM> within the apertures 552B, 552D, 552F, and <NUM> of the bottom plate <NUM>. In some examples, all of the top plate apertures <NUM> may be smaller than the bottom plate apertures <NUM>.

A plurality of pin fins <NUM> can be provided within the pin fin receptacle <NUM>. The pin fins <NUM> can be comprised of any material that can thermally conduct heat away from the IC die <NUM>. Examples of materials forming the plurality of pin fins <NUM> include copper, aluminum, tungsten, gold, silver, combinations thereof, or alloys thereof. A pin fin vacuum chamber <NUM> can overlie top plate <NUM>. As shown in <FIG>, vacuum pickup suction generated by the vacuum pump <NUM> of vacuum pickup assembly <NUM> will draw or pull the pin fins <NUM> up into the apertures 552B, 552D, 552F, <NUM> of bottom plate <NUM>. The portions of the bottom surface <NUM> of the top plate <NUM> that overlie apertures 552B, 552D, 552F, <NUM> in bottom plate <NUM> will prevent pin fins <NUM> from being pulled into the top plate apertures <NUM> and into vacuum chamber <NUM>. As shown, pin fins <NUM> will be secured within apertures 552B, 552D, 552F, <NUM> of bottom plate <NUM> due to vacuum suction securing the top portions <NUM> of the pin fins <NUM> against the bottom surface <NUM> of top plate <NUM>.

Once the pin fins <NUM> are secured in place within plate body <NUM>, and in this example, within apertures 552B, 552D, 552F, and <NUM> of bottom plate <NUM>, the pin fin receptacle <NUM> may be removed, as shown in <FIG>. Vacuum suction from the vacuum pickup assembly <NUM> may continue to secure the pin fins <NUM> within apertures 552B, 552D, 552F, <NUM> of bottom plate <NUM>, while further processing takes place.

With the pin fin receptacle <NUM> removed, the pin fins <NUM> may be joined to another microelectronic device or assembly. In one example, pin fins <NUM> may be coupled to IC die <NUM> and PCB <NUM>. As shown in <FIG>, pin fins <NUM> may be aligned with solder connections <NUM>, as the IC die <NUM> and PCB <NUM> are joined to bottom plate <NUM>. While solder connections <NUM> are in the process of being aligned with pin fins <NUM>, the vacuum pickup assembly <NUM> will remain active and secure pin fins <NUM> within the apertures 552B, 552D, 552F, <NUM> of bottom plate <NUM>. The cooling chamber supports <NUM> may also be coupled to the rear surface <NUM> of the IC die <NUM>. This creates an enclosed interior cavity <NUM> between the bottom surface <NUM> of the bottom plate <NUM> and the rear surface <NUM> of the IC die <NUM>.

Once pin fins <NUM> are aligned with solder connections <NUM>, vacuum pickup assembly <NUM> may be removed, along with top plate <NUM>. As shown in <FIG>, the remaining portions of pin fin placement assembly <NUM>, which in this example includes the bottom plate <NUM> and supports <NUM>, in addition to IC die <NUM> and PCB <NUM>, form an in-process thermal assembly <NUM>. The in-process assembly <NUM> may undergo thermal processing and in some examples, may be reflowed to secure pin fins <NUM> to IC die <NUM>. With the remaining portions of the pin fin placement assembly <NUM> remaining in place during further thermal processing, proper alignment of each of the pin fins <NUM> to the solder connections <NUM> can be accomplished. Solder balls <NUM> may also be reflowed in this step, although may have already been reflowed at an earlier stage.

After reflow, further thermal processing may take place. In one example, as shown in <FIG>, a manifold <NUM> may be joined to the rear surface <NUM> of bottom plate <NUM>. An adhesive material or other mechanism (e.g., screws) or material for securing manifold <NUM> to the bottom plate <NUM> can be utilized. Manifold <NUM> overlies all of the top surfaces <NUM> of the plurality of thermal dissipating elements <NUM>, which include pin fins <NUM>. In this example, part of bottom surface <NUM> of manifold <NUM> is shown spaced apart from pin fins <NUM> in apertures 552A, 552B, 552C, 552D, and 552E, so as to create channels or passageways for liquid coolant within the pin fin assembly to be disposed around exposed surfaces of pin fins <NUM>. As shown, bottom surface <NUM> of manifold <NUM> overlying pin fins <NUM> within apertures 525F and <NUM> of bottom plate <NUM> is directly connected to and covers top surfaces <NUM> of the plurality of pin fins <NUM>, such that only a lower portion <NUM> of each of the plurality of thermal dissipating elements <NUM> will be exposed. As in the previous example, the combination of the manifold <NUM>, bottom plate <NUM>, and cooling chamber supports <NUM> may collectively form a thermal cooling structure <NUM>.

The different configurations of the thermal dissipating elements <NUM> may be utilized to enhance thermal energy circulation and thermal dissipation efficiency. Once the manifold <NUM> is secured to the PCB <NUM> and IC die <NUM>, the installation of the cooling structure <NUM> is then considered completed. With the manifold <NUM> in place, a cooling medium may be supplied to the plenum <NUM> to facilitate temperature control and cooling of the IC die <NUM> through the plurality of thermal dissipating elements <NUM> disposed on the IC die <NUM>. For example, fluid, air, liquid, or other such cooling material to be introduced therein to the IC die <NUM> and thermal cooling elements <NUM>. Variation of the pin apertures allows for a different flow of cooling liquid prevents liquid coolant pressure from breaking the soldering joints, so as to provide long term reliability. In contrast to the prior example, cooling liquid may now flow over the top surfaces <NUM> of thermal dissipating elements <NUM>, including pin fins <NUM> secured within apertures 552B and 552D of bottom plate <NUM>, as well as travel through apertures 552A, 552C, 552E in bottom plate <NUM>. In this example, the cooling structure <NUM>, including manifold <NUM> and remaining portions of pin fin assembly <NUM>, can remain in place during liquid cooling. This allows for the pin fins <NUM> to remain accurately positioned and secured to IC die <NUM> during liquid cooling, thereby preventing liquid coolant pressure from breaking the solder joints. This cooling structure <NUM> may remain in place and be utilized throughout liquid cooling. It is to be appreciated that the interior cavity formed by the combination of the manifold <NUM> and bottom plate <NUM> can vary widely and according to desired specifications.

The prior examples described with regard to <FIG> and <FIG> discuss incorporating the remaining components of the respective pin fin placement assemblies <NUM>, <NUM>, namely respective bottom plates <NUM>, <NUM>, along with the respective manifolds <NUM>, <NUM>, and cooling chamber supports <NUM>, <NUM> into the respective final thermal conductive structures <NUM>, <NUM>. In alternative examples, it may be desired to instead remove the remaining components of the pin fin placement assembly altogether so that the pin fin placement assembly does not structurally remain as a part of the thermal conductive structure, and only the manifold forms a thermal conductive structure. For example, after reflow of the in-process thermal assembly <NUM> described in <FIG>, instead of proceeding with the manufacturing process shown in <FIG>, the remaining components of the pin fin placement assembly <NUM> can alternatively be removed altogether. For example, as shown in <FIG>, this leaves behind the IC die <NUM>, PCB element <NUM>, and the thermally conductive structures <NUM>, including pin fins <NUM>, that are joined to IC die <NUM> by a solder connection <NUM>.

As shown in <FIG>, a manifold, such as manifold <NUM>, maybe joined to the IC die <NUM> and PC board <NUM>, as previously described herein. The manifold <NUM> can provide a structure to help thermally dissipate heat from the IC die <NUM> and the surrounding environment during use. In this example, manifold <NUM> is utilized to encase the IC die <NUM>, along with the thermal dissipating elements <NUM>, such as pin fins <NUM>. Manifold <NUM> includes a first sidewall <NUM> and a second sidewall <NUM> connected together by a ceiling <NUM>. This configuration forms a substantially U-shaped body that defines a central cavity <NUM> within the manifold <NUM> and encases IC die <NUM> when the manifold <NUM> is placed or mounted to the PCB <NUM>. The manifold <NUM> may be joined to the PCB <NUM> using various means, and in this example, an adhesive <NUM> joins a top surface of PCB <NUM> to and the first and second sidewalls <NUM>, <NUM>. The adhesive material <NUM> provides a sealing interface between the manifold <NUM> and the PCB <NUM>.

A sealing member may be utilized to seal the interface where the manifold <NUM> contacts the IC die <NUM>. In some examples, sealing member <NUM> may be an adhesive material, an O ring, or suitable mechanical attachments that facilitate positioning and securement of the manifold <NUM> to the IC die <NUM>. A plenum <NUM> may be defined by the ceiling <NUM> of the manifold <NUM>.

Once the manifold <NUM> is positioned on the PCB <NUM> with the plurality of thermal dissipating elements <NUM> disposed on the IC die <NUM>, the installation of the manifold <NUM> is then considered completed and liquid cooling can take place. As shown in <FIG>, the plenum <NUM> may allow a cooling medium, including cooling fluid, air, liquid, or other such cooling material to be introduced therein for temperature control purposes to the IC die <NUM>. Such cooling materials may enter the plenum through inlet <NUM> of the plenum <NUM>, around thermal control elements <NUM>, and exit the plenum through outlet <NUM>.

Another example manifold <NUM> that may be implemented in connection with a same or different arrangement of thermal conductive components <NUM> is discussed in <FIG>. For example, after reflow of the in-process thermal assembly <NUM> described in <FIG>, instead of proceeding with the manufacturing process shown in <FIG>, the remaining components of the pin fin placement assembly <NUM> can alternatively be removed altogether. As shown in <FIG>, removal of the remaining components of the pin fin assembly results in a structure that includes PCB <NUM>, IC die <NUM>, and thermally conductive elements <NUM>, including pin fins <NUM> that are joined to IC die <NUM> by solder connections <NUM>. In <FIG>, manifold <NUM> may include a first sidewall <NUM> and a second sidewall <NUM> connected together by a ceiling <NUM>. As shown, the bottom surface <NUM> of ceiling <NUM> has two different heights H1 and H2 away from the rear surface <NUM> of IC die <NUM>, as well as a height H3 away from some of the thermally conductive elements <NUM>, and in this example, top surfaces <NUM> of some of the pin fins <NUM>. As shown in <FIG>, the variation in height allows for a variation in the cooling material through the plenum <NUM> of the manifold <NUM>, as well as more control over the distribution of cooling material through the plenum <NUM> and around the thermally conductive elements <NUM>.

It is to be appreciated that although the prior embodiments illustrate use of a multi-plate system within the pin-fin assembly, a single plate can also be implemented. For example, <FIG> illustrate another example pin fin assembly <NUM> that includes a vacuum pickup assembly <NUM>. This example differs from the previous examples in that instead of the plate body <NUM> having an upper plate, middle plate, and/or bottom plate, the plate body <NUM> is a single plate <NUM>-<NUM>. Plate <NUM>-<NUM> includes a top surface <NUM>, a bottom surface <NUM>, and apertures <NUM> that extend through the top surface <NUM> and bottom surface <NUM>. Apertures <NUM> extend through the top and bottom surfaces <NUM> and <NUM> and have a configuration in which each of the apertures <NUM> includes an upper portion <NUM> that has a diameter or length L6 that is smaller than a diameter or length L7 of the lower portion <NUM>. An edge surface <NUM> is formed at the transition in the diameters between the upper portion <NUM> and lower portion <NUM>. Edge surface <NUM> is just one example of the transition between the upper portion <NUM> and lower portion <NUM>, but other shapes and types of surfaces may be implemented to create a surface against which a thermal dissipating element, such as pin fin <NUM>, can be held.

As shown in <FIG>, apertures <NUM> may be configured to receive pin fins <NUM> in the lower portion <NUM> of apertures <NUM>. Vacuum pickup suction from the vacuum pickup assembly <NUM> will pull pin fins <NUM> from a receptacle <NUM> into the apertures <NUM>, and in this example the lower portions <NUM> of the apertures <NUM>. The top surfaces <NUM> of the pin fins <NUM> will be held in place against the edge surfaces <NUM>. In other examples, various cut out shapes within the apertures <NUM> or other edge surfaces can be created to provide a surface against which top surfaces <NUM> of pin fins <NUM> may be adjacent to and/or which will prevent pin fins <NUM> from moving to the upper portions <NUM> of the apertures <NUM>.

Once the pin fins <NUM> are in place, the pin fin receptacle <NUM> may be removed, as shown in <FIG>. Vacuum suction from the vacuum pickup assembly <NUM> may continue to secure the pin fins <NUM> within the lower portion <NUM> of apertures <NUM> of plate <NUM>-<NUM>, while further processing takes place.

With the pin fin receptacle <NUM> removed, the pin fins <NUM> may be joined to another microelectronic device or assembly. In one example, pin fins <NUM> may be coupled to IC die <NUM> and PCB <NUM>, as shown in <FIG> and previously described herein. As in previous examples, pin fins <NUM> may be aligned with solder connections <NUM>, as the IC die <NUM> and PCB <NUM> are coupled to plate <NUM>-<NUM> of the pin fin placement assembly <NUM>. While the solder connections <NUM> are in the process of being aligned with the pin fins <NUM>, the vacuum pickup assembly <NUM> will remain active and secure the pin fins <NUM> within the apertures <NUM>. The cooling chamber supports <NUM> may also be coupled to the rear surface <NUM> of the IC die <NUM>. This creates an enclosed interior cavity <NUM> between the bottom surface <NUM> of plate <NUM>-<NUM> and the rear surface <NUM> of IC die <NUM>.

Once pin fins <NUM> are aligned with solder connections <NUM>, the vacuum pickup assembly <NUM> may be removed. As shown in <FIG>, removal of the vacuum pickup assembly <NUM> results in an in-process thermal assembly 800A and further thermal processing can take place. As previously discussed, a manifold (not shown) can be provided on the top surface <NUM> of plate <NUM>-<NUM> of the pin fin placement assembly <NUM> or alternatively, the plate <NUM>-<NUM> can be removed altogether and a manifold can be coupled to the IC die <NUM> and PCB <NUM> without use of the pin fin placement assembly <NUM>.

<FIG> depicts a cross-sectional view of the plurality of thermal dissipating elements <NUM> and <FIG> depicts a top view of the thermal dissipating elements <NUM> of <FIG>. As described above, the thermal dissipating element <NUM> includes the plurality of pin fins <NUM> disposed on the solder connections <NUM>. The thermal dissipating element <NUM> may be configured as arrays or matrix that includes multiple thermal dissipating elements <NUM> equally or non-equally spaced apart from each other. As depicted in the top view of the thermal dissipating element <NUM> in <FIG>, the thermal dissipating element <NUM> may be configured in a circular configuration to facilitate thermal dissipation. In one example, the thermal dissipating element <NUM> may have a diameter between about <NUM> and about <NUM>. In other examples, the diameter may be less than <NUM> and greater than <NUM>.

In another example, depicted in <FIG>, the thermal dissipating element <NUM>-<NUM> includes the plurality of pin fins <NUM>-<NUM> disposed on solder connections <NUM>,-<NUM> as shown in the cross-sectional view of <FIG>. The thermal dissipating elements <NUM>-<NUM> may be configured as arrays or matrix that includes multiple thermal dissipating elements <NUM>-<NUM> equally or non-equally spaced apart from each other. The thermal dissipating element <NUM>-<NUM> may be configured to have a rectangular configuration, as shown in the top view in <FIG>. The thermal dissipating element <NUM>-<NUM> may be a longitudinal structure. For example, the thermal dissipating element <NUM>-<NUM> may have a dimension between about <NUM> and about <NUM>.

Based on different configurations, densities, distributions, and profiles of the pin fins disclosed herein, the apertures formed in any one of the previously disclosed plates may be changed or altered accordingly to accommodate different configurations, densities, distributions, and profiles of the pin fins.

<FIG> depict example flow diagrams for manufacturing an IC package that includes an IC die having thermal dissipating elements to control the temperature of the IC die in accordance with aspects of the disclosure. It should be understood that the operations involved in the following methods need not be performed in the precise order described. Rather, various operations may be handled in a different order or simultaneously, and operations may be added or omitted.

Referring to <FIG>, blocks <NUM> through <NUM> of the flow diagram illustrate an example <NUM> for bonding thermal dissipating elements to an IC die.

In block <NUM>, a thermal dissipating element placement assembly is provided that comprises at least one plate and a plurality of apertures extending through a top surface and a bottom surface of the at least one plate. The thermal dissipating element placement assembly can comprise a single plate or multi-plate structure with apertures therein for receiving pin fins.

In block <NUM>, vacuum suction created by a vacuum pickup assembly may be used to position and removably secure the thermal dissipating elements within the plurality of apertures.

In block <NUM>, the thermal dissipating elements positioned within the plurality of apertures may be joined with an IC die.

In block <NUM>, while the thermal dissipating elements are positioned within the thermal dissipating element placement assembly, a bonding material disposed between the thermal dissipating elements and the IC die to bond the thermal dissipating elements to the IC die may be reflowed. In some examples, a solder connection between the IC die and the plurality of pin fins may be formed.

Block <NUM> illustrates an optional block, in which a manifold may be coupled to the thermal dissipating element placement assembly. The manifold may include an inlet and an outlet configured to receive cooling material therein, the manifold providing further thermal dissipation of the IC die.

Referring to <FIG>, blocks <NUM> through <NUM> of the flow diagram illustrate another example <NUM> for bonding thermal dissipating elements to an IC die. At block <NUM>, a pin fin placement assembly with a vacuum pickup assembly coupled thereto is provided. The pin fin placement assembly comprises a first plate, a second plate, and a third plate.

At block <NUM>, vacuum suction created by a vacuum pickup assembly is used to pull a plurality of pin fins into apertures of a first plate of the pin fin placement assembly. The plurality of pin fins may be supported within apertures of the first plate of the pin fin placement assembly by the second plate, which underlies the first plate.

At block <NUM>, the second plate is laterally moved laterally moved relative to the first and third plates to allow the plurality of pin fins in the apertures of the first plate to be positioned within apertures of the third plate.

At block <NUM>, while the pin fins remain within apertures of the third plate, the pin fins may be positioned adjacent a rear surface of the IC die and a material disposed between the pin fins and the IC die may be reflowed to bond the pin fins to the IC die, thereby forming a plurality of thermal dissipating elements at the surface of the IC die.

At block <NUM>, while the pin fins remain within the pin fin placement assembly, reflowing a material disposed between the pin fins and the IC die to bond the pin fins to the IC die, thereby forming a plurality of pin fins or thermal dissipating elements at the surface of the IC die.

Block <NUM> illustrates an optional block, in which a manifold may be coupled to the IC die while the pin fins remain within the pin fin placement assembly.

The features described herein provide improved methods and structures for formation of thermal dissipation elements on the rear surface of an IC die using an improved thermal dissipation element placement assembly with a vacuum pickup assembly, as well as providing methods and structures for the optional addition of a thermal cooling structure, such as a manifold alone or in combination with the thermal dissipation element placement assembly. Both methods and structures may provide high heat dissipation efficiency to an IC die during operation assembled in the package assembly. The pin fins attached to the rear surface of the IC die, alone or in combination with a manifold encasing the IC die may assist in temperature control of the IC die when in operation. In one example, a plurality of thermal dissipating elements may be disposed on a first surface of the IC die encased under a manifold to efficiently control and dissipate the thermal energy from the IC die when in operation. A second surface opposite to the first surface of the IC die may include a plurality of devices, such as semiconductors transistors, devices, electrical components, circuits, or the like, that may generate thermal energy when in operation. The thermal dissipating elements may be manufactured by utilizing the thermal dissipation element placement assembly to position thermal dissipation elements efficiently and precisely, such as pin fins on desired locations of the IC die. Different configurations of the thermal dissipating elements may be utilized to accommodate different device layouts with different thermal energy generation across the substrate in the IC die. Thus, an IC die package can be provided with high efficiency of heat dissipation that is suitable for 3D IC package structures and requirements.

According to an aspect of the disclosure, an assembly for positioning a plurality of thermal dissipating elements on an integrated circuit ("IC") die comprises a thermal dissipating element placement assembly and a vacuum pickup assembly. The thermal dissipating element further comprises a plate body having a first plate and a second plate. The first plate has a first plurality of apertures extending through top and bottom surfaces of the first plate. The second plate may also have a second plurality of apertures extending through top and bottom surfaces of the second plate. Each of the second plurality of apertures may have a diameter that is different than a diameter of each of the first plurality of apertures. The second plurality of apertures may be aligned with the first plurality of apertures. The vacuum pickup assembly may be removably coupled to the thermal dissipating element placement assembly. The vacuum pickup assembly may provide a suction force that holds the plurality of thermal dissipating elements within the first or second plurality of apertures in the plate body and against a surface of the plate body; and/or.

According to another aspect of the disclosure, an assembly for positioning thermal dissipating elements on an integrated circuit ("IC") die comprises a thermal dissipating element placement assembly and a vacuum pickup assembly. The thermal dissipating element placement assembly may comprise a top plate, a middle plate, and a lower plate vertically assembled to form a plate body. The middle plate may be movable relative to the top plate and/or the lower plate. A first plurality of apertures may be formed in the top plate; and a second plurality of apertures may be formed in the lower plate. The first and the second plurality of apertures are vertically aligned. The first and the second plurality of apertures may be configured to receive the thermal dissipating elements therein. The thermal dissipating elements may be configured to be disposed on an IC die. The vacuum pickup assembly may be removably coupled to the thermal dissipating element placement assembly. The vacuum pickup assembly may be configured to hold the thermal dissipating elements against at least a portion of the plate body; and/or.

According to another aspect of the disclosure, an assembly comprises an integrated circuit ("IC"), a thermal dissipating element placement assembly, a plurality of thermal dissipating elements and a manifold. The IC die may be electrically connected to a printed circuit board ("PCB"). The thermal dissipating element placement assembly may be coupled to the PCB. The thermal dissipating element placement assembly may comprise a plate body having a top surface, a bottom surface, and a plurality of apertures extending through the top and bottom surfaces. The plurality of thermal dissipating elements may be disposed within the plurality of apertures and coupled to a surface of the IC die. The manifold may be coupled to the plate body and the IC die, the manifold configured to provide thermal dissipating of the IC die; and/or.

According to another aspect of the disclosure, a method for providing thermal dissipating elements on an integrated circuit ("IC") die, comprises providing a thermal dissipating element placement assembly comprising at least one plate and a plurality of apertures extending through a top surface and a bottom surface of the at least one plate; using vacuum suction created by a vacuum pickup assembly to position and removably secure the thermal dissipating elements within the plurality of apertures; and joining the thermal dissipating elements positioned within the plurality of apertures with an IC die. While the thermal dissipating elements are positioned within the thermal dissipating element placement assembly, a bonding material disposed between the thermal dissipating elements and the IC die may be reflowed to bond the thermal dissipating elements to the IC die; and/or.

Claim 1:
An assembly for positioning a plurality of thermal dissipating elements (<NUM>) on an integrated circuit, IC, die (<NUM>) comprising:
a thermal dissipating element placement assembly comprising:
a plate body (<NUM>) comprising a first plate (<NUM>) and a second plate (<NUM>), the first plate (<NUM>) having a first plurality of apertures (<NUM>) extending through top and bottom surfaces of the first plate (<NUM>) and the second plate (<NUM>) having a second plurality of apertures (<NUM>) extending through top and bottom surfaces of the second plate (<NUM>), each of the second plurality of apertures (<NUM>) having a second diameter that is different than a first diameter of each of the first plurality of apertures (<NUM>), the second plurality of apertures (<NUM>) being aligned with the first plurality of apertures (<NUM>), and
a vacuum pickup assembly (<NUM>) removably coupled to the thermal dissipating element placement assembly, the vacuum pickup assembly (<NUM>) providing a suction force that holds the plurality of thermal dissipating elements (<NUM>) within the first (<NUM>) or second plurality of apertures (<NUM>) in the plate body (<NUM>) and against a surface of the plate body (<NUM>).