CN117203758A

CN117203758A - Integrated circuit package having a heat transfer conduit including thermally conductive nanoparticles

Info

Publication number: CN117203758A
Application number: CN202280029002.6A
Authority: CN
Inventors: B·陈; J·萨托
Original assignee: Microchip Technology Inc
Current assignee: Microchip Technology Inc
Priority date: 2021-08-18
Filing date: 2022-08-18
Publication date: 2023-12-08

Abstract

An electronic device includes an integrated circuit package, the integrated circuit package comprising: a die mounted on the die carrier; a mold structure at least partially encapsulating the mounted die; and a heat transfer conduit formed over the die. The heat transfer conduit extends at least partially through the mold structure to transfer heat away from the die. The heat transfer conduit is formed from a thermally conductive compound comprising thermally conductive nanoparticles.

Description

Integrated circuit package having a heat transfer conduit including thermally conductive nanoparticles

Related patent application

The present application claims priority from commonly owned U.S. provisional patent application 63/234,604 filed 8/18 of 2021, the entire contents of which are hereby incorporated by reference for all purposes.

Technical Field

The present disclosure relates to Integrated Circuit (IC) devices, and more particularly, to IC packages having heat transfer conduits that include thermally conductive nanoparticles.

Background

As integrated circuit devices (semiconductor devices) become smaller and denser, device performance is increasingly limited by thermal constraints. In addition, integrated circuit devices are generally susceptible to magnetic fields and ionizing radiation that negatively impact device performance.

There is a need for improved thermal management in IC devices, for example, to remove heat from a heat generating die. There is also a need to improve the shielding of IC devices from magnetic fields and ionizing radiation that may damage or affect the performance of the IC devices.

Disclosure of Invention

One aspect provides an electronic device comprising: an Integrated Circuit (IC) package, the IC package comprising: a die mounted on a die carrier; a mold structure at least partially encapsulating the mounted die; and a heat transfer conduit formed on the die and extending at least partially through the mold structure to transfer heat away from the die. The heat transfer conduit is formed from a thermally conductive compound comprising thermally conductive nanoparticles.

In some examples, the heat transfer conduit extends through the entire thickness of the mold structure, wherein a distal surface of the heat transfer conduit is exposed through an outer surface of the mold structure.

In some examples, the die carrier includes a leadframe or interposer.

In some examples, the thermally conductive nanoparticles include at least one of diamond nanoparticles, silicon carbide nanoparticles, boron nitride nanoparticles, hexagonal boron nitride nanoparticles, or boron nitride nanotubes.

In some examples, the thermally conductive compound includes thermally conductive nanoparticles dispersed in a polymer resin.

In some examples, the thermally conductive compound includes thermally conductive nanoparticles and silica dispersed in an epoxy resin.

In some examples, the mold structure includes magnetic shielding nanoparticles to shield the die from the magnetic field.

In some examples, the magnetically shielded nanoparticle comprises a high magnetic alloy or hematite (Fe ₂ O ₃ ) At least one of them.

In some examples, the mold structure includes radiation-shielding nanoparticles to shield the die from ionizing radiation.

In some examples, the shielding nanoparticles include Boron Nitride (BN), bismuth (Bi), bismuth oxide (Bi) ₂ O ₃ ) Tantalum nitride (TaN), tungsten nitride (W) ₃ N ₂ ) Tin oxide (SnO) ₂ ) Copper (I) oxide (Cu) ₂ O) (i.e., cuprous oxide) or copper (II) oxide (CuO) (i.e., cupric oxide).

In some examples, the electronic device includes a shielding layer formed over the mold structure, the shielding layer including at least one of: (a) Magnetic shielding nanoparticles for shielding the die from magnetic fields; or (b) radiation-shielding nanoparticles for shielding the die from ionizing radiation.

In some examples, the electronic device includes a multi-layer shield formed over the mold structure, wherein the multi-layer shield includes a plurality of different shield layers, wherein each of the plurality of different shield layers includes shielding nanoparticles to shield the die from at least one of magnetic field or ionizing radiation, wherein the plurality of different shield layers include different types or concentrations of shielding nanoparticles.

In some examples, the different types or concentrations of shielding nanoparticles in the plurality of different shielding layers of the multi-layer shield define a shielding gradient.

In some examples, the integrated circuit package is mounted on a first side of a package support structure, and the electronic device includes a backside shielding layer formed on a second side of the package support structure opposite the first side, the backside shielding layer including shielding nanoparticles to shield the die from at least one of magnetic field or ionizing radiation.

In some examples, the package support structure includes a printed circuit board or interposer.

One aspect provides a method comprising: forming an integrated circuit package, the integrated circuit package comprising: mounting a die on a die carrier; forming a heat transfer conduit over the die; forming a mold structure at least partially encapsulating the die; wherein the heat transfer conduit extends at least partially through the mold structure; and wherein the heat transfer conduit includes thermally conductive nanoparticles to transfer heat away from the die.

In some examples, the method includes: forming a thermally conductive compound comprising mixing (a) silica particles and (b) thermally conductive nanoparticles with a polymer; and forming the heat transfer conduit from the thermally conductive compound.

In some examples, the method includes: forming a thermally conductive compound comprising: (a) Mixing a surfactant with the thermally conductive nanoparticles to form surfactant-coated thermally conductive nanoparticles; and (b) mixing the surfactant-coated thermally conductive nanoparticles with a polymer; and forming the heat transfer conduit from the thermally conductive compound.

In some examples, the method includes: forming a thermally conductive compound comprising: (a) Mixing a surfactant with the thermally conductive nanoparticles to form surfactant-coated thermally conductive nanoparticles; and (b) mixing (i) the surfactant coated thermally conductive nanoparticles and (ii) a silica filler with an epoxy resin; and forming the heat transfer conduit from the thermally conductive compound.

In some examples, forming the thermally conductive compound includes mixing silica particles and thermally conductive nanoparticles with an epoxy resin, wherein the thermally conductive nanoparticles include diamond nanoparticles, silicon carbide nanoparticles, boron nitride nanoparticles, hexagonal boron nitride nanoparticles, or boron nitride nanotubes.

In some examples, forming the heat transfer conduit on the die includes printing the heat transfer conduit using an additive printing process.

In some examples, the method includes: mixing the shielding nanoparticles with a mold compound to form a nanoparticle-reinforced mold compound; and forming the mold structure from the nanoparticle-reinforced mold compound.

In some examples, the method includes forming a shielding layer over the mold structure, the shielding layer including at least one of: (a) Magnetic shielding nanoparticles for shielding the die from magnetic fields; or (b) radiation-shielding nanoparticles for shielding the die from ionizing radiation.

In some examples, the method includes forming a plurality of different shielding layers over the mold structure, wherein each shielding layer of the plurality of different shielding layers includes shielding nanoparticles to shield the die from at least one of magnetic field or ionizing radiation, wherein the plurality of different shielding layers include different types or concentrations of shielding nanoparticles.

One aspect provides a method comprising: forming a first integrated circuit package, the first integrated circuit package comprising: mounting a first integrated circuit die; and forming a mold structure at least partially encapsulating the first integrated circuit die; and thermally analyzing the first integrated circuit package. The method further comprises the steps of: forming a second integrated circuit package, the second integrated circuit package comprising: determining a first conduit location based on the thermal analysis of the first integrated circuit package; and forming a first heat transfer conduit on the second integrated circuit die at the determined first conduit location.

In some examples, the method further comprises: performing a thermal analysis on the second integrated circuit package; and forming a third integrated circuit package, the third integrated circuit package comprising: determining a second conduit location different from the first conduit location based on the thermal analysis of the second integrated circuit package; and forming a second heat transfer conduit on the third integrated circuit die at the determined second conduit location.

Drawings

Exemplary aspects of the disclosure are described below in conjunction with the following drawings, in which:

FIG. 1 is a cross-sectional side view illustrating an exemplary integrated circuit package including a heat transfer conduit containing thermally conductive nanoparticles;

FIGS. 2A-2F illustrate an exemplary process for forming the exemplary integrated circuit package shown in FIG. 1;

fig. 3 is a cross-sectional side view of an exemplary leadframe package including a heat transfer tube containing thermally conductive nanoparticles;

FIG. 4 is a cross-sectional side view of an exemplary Ball Grid Array (BGA) package, the exemplary BGA package comprising heat transfer conduits comprising thermally conductive nanoparticles;

FIG. 5 is a cross-sectional side view of an exemplary flip chip plastic ball grid array (FC-PBGA) package including a heat transfer conduit containing thermally conductive nanoparticles;

FIG. 6 is a cross-sectional side view of an exemplary IC package including first and second dies and respective heat transfer conduits formed on the respective first and second dies;

FIG. 7 is a cross-sectional side view of an exemplary electronic device including the exemplary leadframe package shown in FIG. 3 mounted on a PCB and including shielding layers formed on top and bottom sides of the PCB;

fig. 8 is a cross-sectional side view of an exemplary electronic device including two dies arranged in a stacked manner on a PCB, with a heat transfer conduit formed on a second die;

FIG. 9 is a flow chart illustrating an exemplary method for forming an integrated circuit package including a heat transfer conduit containing thermally conductive nanoparticles; and is also provided with

FIG. 10 is a flow chart illustrating an exemplary method for analyzing and adjusting the position of a heat transfer conduit.

It will be appreciated that the reference numerals of any illustrated element appearing in a plurality of different figures have the same meaning in the plurality of figures, and that any illustrated element mentioned or discussed herein in the context of any particular figure is also applicable to every other figure (if any), where the same illustrated element is shown.

Detailed Description

The present disclosure provides an IC package that includes a heat transfer conduit formed from a thermally conductive compound to improve thermal management of the individual IC package, the thermally conductive compound including thermally conductive nanoparticles, such as diamond nanoparticles, silicon carbide (SiC) nanoparticles, boron Nitride (BN) nanoparticles, hexagonal boron nitride (h-BN) nanoparticles, or Boron Nitride Nanotubes (BNNTs). In some examples, the heat transfer conduit may be formed by an additive printing process (e.g., a 2D, 2.5D, or 3D printing process). The heat transfer conduit including thermally conductive nanoparticles may improve heat transfer from the die, which may reduce the operating temperature of the die, reduce dark silicon, increase battery life, or otherwise improve performance of the corresponding IC package.

Some examples also include shielding nanoparticles, e.g., for shielding the die (or dies) from magnetic fields and/or ionizing radiation, the shielding nanoparticles being disposed in a mold enclosure formed over the die and/or in an additional shielding layer formed over the mold enclosure. For example, IC devices containing radiation shielding nanoparticles may be provided for Low Earth Orbit (LEO) applications requiring or benefiting from improved radiation shielding. As another example, magnetically sensitive products (e.g., magnetoresistive Random Access Memory (MRAM) or chip-level atomic clocks) may benefit from high permeability magnetic shielding.

Fig. 1 is a cross-sectional side view illustrating an exemplary integrated circuit package 100 including a die 102 mounted on a die carrier 104, a heat transfer conduit 110 formed on the die 102, and a mold structure 106 (e.g., a mold encapsulant) at least partially encapsulating the mounted die 102. The heat transfer conduit 110 may extend at least partially through the die structure 106 to transfer heat away from the die 102. The heat transfer conduit 110 may be formed from a thermally conductive compound 112 that includes thermally conductive nanoparticles 114. In some examples, the heat transfer conduit 110 extends through the entire thickness of the mold structure 106 such that a distal surface 118 of the heat transfer conduit 110 is exposed through the outer surface 108 of the mold structure 106.

Die 102 may include any type of die, chip (e.g., a silicon substrate with integrated circuits formed thereon), or other integrated circuit device (e.g., including analog devices, digital devices, or a mixture of analog and digital devices) that generates or outputs heat. For example, die 102 may include a microprocessor (e.g., a Central Processing Unit (CPU) chip), a Microcontroller (MCU), an Application Specific Integrated Circuit (ASIC), a Graphics Processing Unit (GPU), a Digital Signal Processor (DSP), an a/D converter or a D/a converter, or memory (e.g., flash memory, random Access Memory (RAM), read Only Memory (ROM) (e.g., electrically Erasable Programmable Read Only Memory (EEPROM) or other memory), or a system on chip (SoC) device).

The die carrier 104 may include any structure on which the die 102 may be mounted, such as a Printed Circuit Board (PCB), a leadframe, an interposer, a heat sink, or another die. The die 102 may be mounted on the die carrier 104 in any suitable manner, such as solder mounting, adhesive bonding (e.g., using epoxy), flip chip bonding, or eutectic bonding.

As described above, the heat transfer conduit 110 formed on the die 102 may be formed from a thermally conductive compound 112 including thermally conductive nanoparticles 114 and used to transfer heat away from the die 102.

In some examples, the thermally conductive compound 112 includes thermally conductive nanoparticles 114 dispersed in a base polymer (e.g., an epoxy). In some examples, the thermally conductive compound 112 includes thermally conductive nanoparticles 114 dispersed in or otherwise combined with a base compound 116 (e.g., a polymer resin). In some examples, thermally conductive compound 112 further comprises silicon dioxide (SiO ₂ ) Fillers (e.g., in the form of fumed silica or colloidal silica) to thicken or otherwise enhance the structural integrity of the base compound (e.g., epoxy resin) 116. Thus, the thermally conductive compound 112 may include thermally conductive nanoparticles 114 and Silica (SiO) dispersed in or otherwise combined with an epoxy ₂ ) And (3) filling. As used herein, a "compound" may refer to an element or substance or multiple speciesMixtures of elements or substances or other combinations. As used herein, the term nanoparticle refers to particles having a largest dimension of 1 to 100 nanometers.

In some examples, thermally conductive nanoparticles 114 include at least one of diamond nanoparticles, silicon carbide (SiC) nanoparticles, boron Nitride (BN) nanoparticles, hexagonal boron nitride (h-BN) nanoparticles, or Boron Nitride Nanotubes (BNNTs). In some examples, the thermally conductive compound 112 includes a mixture of thermally conductive nanoparticles 114 and a base compound 116 including an epoxy or an epoxy and silica (SiO ₂ ) Is a mixture of (a) and (b).

The heat transfer conduit 110 may be formed on the die 102 in any suitable manner. In some examples, the heat transfer conduit 110 may be printed on the die 102 using an additive printing process (e.g., a 2D, 2.5D, or 3D printing process). In such an example, the horizontal lines shown in the heat transfer conduit 110 (in all figures) may represent a printed layer of the thermally conductive compound 112. In other examples, the heat transfer conduit 110 may be formed by injection molding or spin coating using a nozzle (e.g., using a microliter/minute flow rate). In some examples, the heat transfer conduit 110 may be formed on the die 102 at selected locations or areas of the die 102, e.g., heat generating areas of the die 102 (e.g., as determined based on thermal analysis, as discussed below with reference to fig. 10).

In some examples, the mold structure 106 may also include performance enhancing nanoparticles. For example, the mold structure 106 may include a nanoparticle reinforced mold compound 120 that includes shielding nanoparticles 122 dispersed in or otherwise combined with a base mold compound 124. The base mold compound 124 may include, for example, an elastomer (e.g., silicone, polyurethane, chloroprene, butyl, polybutadiene, neoprene, natural rubber, or isoprene), a thermoset material (e.g., a thermoset resin), or other mold compound that may be supplied in, for example, a particulate, liquid, or powder form. In some examples, shielding nanoparticles 122 may include nanoparticles that serve to shield die 102 from magnetic fields and/or ionizing radiation. For example, shielding nanoparticles 122 may comprise Includes magnetic shielding nanoparticles for shielding the die from magnetic fields. For example, the magnetically shielded nanoparticles may comprise a high magnetic alloy or hematite (Fe ₂ O ₃ ) And (3) nanoparticles. As another example, shielding nanoparticles 122 may include radiation shielding nanoparticles that are used to shield the die from ionizing radiation. The radiation shielding nanoparticles may include, for example, boron Nitride (BN), bismuth (Bi), bismuth oxide (Bi) ₂ O ₃ ) Tantalum nitride (TaN), tungsten nitride (W) ₃ N ₂ ) Tin oxide (SnO) ₂ ) Copper (I) oxide (Cu) ₂ O) (i.e., cuprous oxide) or copper (II) oxide (CuO) (i.e., cupric oxide) nanoparticles.

In some examples, the example integrated circuit package 100 may optionally include at least one shielding layer 130 formed over the mold structure 106. The illustrated example shows two exemplary shield layers 132 and 134 formed over the mold structure 106, wherein the shield layer 134 is formed over the shield layer 132. Other examples include a single shield layer 130 or more than two shield layers 130 (e.g., three, four, or more shield layers 130). Other examples omit the shielding layer 130. Each shielding layer 130 may include shielding nanoparticles dispersed in or otherwise combined with a substrate. For example, each shielding layer 130 may include magnetic shielding nanoparticles and/or radiation shielding nanoparticles, e.g., as discussed above with respect to the mold structure 106.

In examples with multiple shielding layers 130, different shielding layers 130 may include different types or different concentrations of shielding nanoparticles. For example, referring to the example shown in fig. 1, the shielding layer 132 may include magnetic shielding nanoparticles (e.g., for shielding the die 102 from magnetic fields) and the shielding layer 134 may include radiation shielding nanoparticles (e.g., for shielding the die 102 from ionizing radiation). As another example, the shielding layers 132 and 134 may include the same type of nanoparticles (e.g., magnetic shielding nanoparticles or radiation shielding nanoparticles), but with correspondingly different concentrations of nanoparticles, thereby defining a shielding gradient in a direction toward or away from the die 102. For example, the shielding layers 132 and 134 may provide a greater degree of shielding in a direction toward the die 102 (e.g., where the shielding layer 132, which may be referred to as an inner shielding layer 132, may provide a greater degree of shielding than the shielding layer 134, which may be referred to as an outer shielding layer 134).

In examples including at least one shielding layer 130, the heat transfer conduit 110 may extend through the shielding layer 130, as shown at 110' in fig. 1. In other examples, the shielding layer 130 may cover the distal end surface 118 of the heat transfer conduit 110.

Fig. 2A-2F illustrate an exemplary process for forming the exemplary integrated circuit package 100 shown in fig. 1.

Fig. 2A is a cross-sectional side view illustrating a die 102 mounted on a die carrier 104 using any suitable mounting technique (e.g., solder mounting, adhesive bonding (e.g., using epoxy), flip chip bonding, or eutectic bonding).

As shown in fig. 2B, a thermally conductive compound 112 is formed. In this example, (a) thermally conductive nanoparticles 114 (e.g., comprising diamond nanoparticles, silicon carbide (SiC) nanoparticles, boron Nitride (BN) nanoparticles, hexagonal boron nitride (h-BN) nanoparticles, or Boron Nitride Nanotubes (BNNTs)) and (b) (optional) silica (SiO ₂ ) The filler 115 (e.g., in the form of fumed silica or colloidal silica) is mixed or otherwise combined with (c) the base compound 116 (e.g., comprising an epoxy resin or other polymer) to produce the thermally conductive compound 112. The thermally conductive nanoparticles 114, (optional) silica filler 115 and base compound 116 may be mixed or combined in any suitable manner, for example, using stirring and/or ultrasonic vibration processes.

In some examples, a surfactant 113 may be (optionally) added to enhance or accelerate the dissolution of the thermally conductive nanoparticles 114 in the base compound (e.g., epoxy) 116. For example, the thermally conductive nanoparticles 114 may be mixed with a surfactant that forms a coating on each thermally conductive nanoparticle 114 (e.g., after waiting for several hours), and the resulting surfactant-coated nanoparticles 114 and silica filler 115 may be mixed with the epoxy 116 (e.g., by stirring or an ultrasonic vibration process). In some examples, the surfactant 113 may include one or more long chain amphiphilic compounds including a hydrophobic group and a hydrophilic group, where such compounds may be classified according to the subtype of the hydrophilic group, e.g., cationic, anionic, zwitterionic, or nonionic surfactants.

In some examples, the thermally conductive nanoparticles 114 (with or without a surfactant coating) and the silica filler 115 may be added to the base compound 116 (e.g., epoxy) in a single step. For example, the thermally conductive nanoparticles 114 may be first mixed with the silica filler 115 and then dispersed in the epoxy. In other examples, the silica filler 115 may be first added to the base compound 116 (e.g., epoxy) to form a base compound/silica mixture, and then the thermally conductive nanoparticles 114 may be dispersed in the base compound/silica mixture.

The thermally conductive nanoparticles 114 and (optionally) the silica filler 115 may include any suitable portion of the resulting thermally conductive compound 112, e.g., a portion defined by a volume fraction. In some examples using epoxy as the base compound 116, the thermally conductive nanoparticles 114 and (optionally) the silica filler 115 may collectively define a volume fraction of at most 85% of the resulting thermally conductive compound 112, which may provide a sufficient amount of epoxy (e.g., at least 15% volume fraction) for the structural integrity of the heat transfer conduit 110 formed from the thermally conductive compound 112. In some examples, thermally conductive nanoparticles 114 may include a volume fraction of 5% -85% of thermally conductive compound 112. In some examples, thermally conductive nanoparticles 114 may include a volume fraction of 50% -75% of thermally conductive compound 112.

As shown in fig. 2C, a heat transfer conduit 110 is formed on the die 102 from a thermally conductive compound 112. In some examples, the heat transfer conduit 110 is printed on the die 102 using an additive printing process (e.g., a 2D, 2.5D, or 3D printer). For example, the heat transfer conduit 110 may be printed as a single layer or multiple layers (e.g., 2-20 layers). In some examples, the heat transfer conduit 110 may be formed by depositing a single droplet or a small number of droplets using a 2D printer (e.g., a 2D nozzle-based inkjet printer). In some examples, 2.5D orThe 3D printer may include, for example, a resin dispensing printer, a 2D inkjet printer, or other 2D fluid dispensing printer (e.g., configured to deposit droplets through a single nozzle or nozzle pattern), a 2.5D fluid dispensing printer (e.g., a fisheman corporation of hopkinton, ma)General Fluids Benchtop Automation with/>Technology) or a 3D top-down printer (e.g., the DM400A DLP 3D printer of Carima, korea, head).

In other examples, the heat transfer conduit 110 may be formed on the die 102 using an injection molding process, for example, using an injection molding nozzle to deposit a single droplet or several droplets of the thermally conductive compound 112.

In some examples, the heat transfer conduit 110 may be formed on the die 102 at selected locations or areas of the die 102 (e.g., heat-generating areas of the die 102). In some examples, thermal analysis may be performed to identify locations on die 102 to form heat transfer conduit 110. As discussed below with reference to fig. 10, such thermal analysis may include an iterative process of forming and analyzing heat transfer tubing at different locations on the respective test equipment to determine a target location of heat transfer tubing 110.

As shown in fig. 2D, nanoparticle reinforced mold compound 120 is formed. In this example, shielding nanoparticles 122 are dispersed in or otherwise combined with a base mold compound 124 to produce nanoparticle-reinforced mold compound 120. In some examples, a surfactant 113 may be (optionally) added to enhance or accelerate dissolution of the shielding nanoparticles 122 in the base mold compound 124, e.g., as discussed above with respect to the thermally conductive nanoparticles 114 dissolved in the base compound 116.

The shielding nanoparticles 122 (with or without a surfactant coating) may be mixed or combined with the base mold compound 124 in any suitable manner (e.g., using stirring or ultrasonic vibration processes). As described above, in some examples, shielding nanoparticles 122 may include magnetic shielding nanoparticles for shielding die 102 from magnetic fields, and/or radiation shielding nanoparticles for shielding die 102 from ionizing radiation. Examples of exemplary shielding nanoparticles 122 (including exemplary magnetic shielding nanoparticles and exemplary radiation shielding nanoparticles) and base mold compound 124 are listed above with reference to fig. 1.

As shown in fig. 2E, the mold structure 106 may be formed over the die 102 from a nanoparticle reinforced mold compound 120. The mold structure 106 may be formed in any suitable manner, for example, by injection molding, compression molding, reaction Injection Molding (RIM), resin Transfer Molding (RTM), or blow molding. In some examples, the mold structure 106 may encapsulate the exposed surface of the die 102, e.g., such that the die 102 is fully encapsulated by the support structure 104, the mold structure 106, the heat transfer conduit 110, and/or other structures formed on or near the die 102. The heat transfer conduit 110 may extend through the formed mold structure 106 such that a distal surface 118 of the heat transfer conduit 110 is exposed through the mold structure 106. For example, the distal surface 118 of the heat transfer conduit 110 is flush with or protrudes above an adjacent top surface 108 of the mold structure 106, e.g., allowing a heat sink or other thermally conductive structure to be placed in direct contact with the heat transfer conduit 110 to transfer heat away from the die 102.

In examples where the optional shielding layer 130 is subsequently formed over the mold structure 106 (e.g., as shown in fig. 2F discussed below), the heat transfer conduit 110 and the mold structure 106 may be formed such that the heat transfer conduit 110 extends beyond (in the example shown, above) the top surface 108 of the mold structure 106 by a distance associated with the total thickness of the shielding layer 130, as shown at 110' in fig. 2F. In such examples, the top surface 118 of the heat transfer conduit 110' may be flush with or protrude above the top surface of the outer shield layer 130, as discussed below.

As shown in fig. 2F, in some examples, at least one shielding layer 130 may be (optionally) formed over the mold structure 106. The illustrated example shows exemplary shielding layers 132 and 134 formed over the mold structure 106. As described above, each of the shielding layers 132 and 134 can include shielding nanoparticles (e.g., magnetic shielding nanoparticles and/or radiation shielding nanoparticles) dispersed in or otherwise combined with a base compound (e.g., an epoxy or other polymer). Exemplary magnetic shielding nanoparticles and exemplary radiation shielding nanoparticles are listed above with reference to fig. 1. As described above, other examples may include a single shielding layer 130 or more than two shielding layers 130, or the shielding layer 130 may be omitted.

In examples including at least one shielding layer 130, the heat transfer conduit 110 may extend through the shielding layer 130, as shown at 110' in fig. 2F. In other examples, the shielding layer 130 may cover the distal end surface 118 of the heat transfer conduit 110 (see fig. 2E).

Fig. 3 is a cross-sectional side view illustrating an exemplary IC package 300 formed as a leadframe package including a die 102 mounted on a leadframe 304. The leadframe 304 may include a die attach pad 306 on which the die 102 is mounted and a plurality of lead fingers 308 arranged around the periphery of the die attach pad 306. Die 102 may be mounted on die attach pad 306 in any suitable manner (e.g., using epoxy or other adhesive). The die 102 may be electrically connected to selected ones of the lead fingers 308 by a plurality of bond wires 314 soldered or otherwise secured to the die 102 and to the respective lead fingers 308.

As shown, the heat transfer conduit 110 may be formed on the die 102 at selected locations or areas on the die 102 using any suitable process, for example, using an additive printing process (e.g., a 2D, 2.5D, or 3D printer) or other process disclosed herein. The heat transfer conduit 110 may be formed from a thermally conductive compound 112 including thermally conductive nanoparticles 114 dispersed in a base compound 116 (e.g., epoxy), for example, as described above. The die 102 may be encapsulated by a mold structure 106, which may extend above and below the die 102 and die attach pad 306. As shown, the mold structure 106 may be formed such that the distal surface 118 of the heat transfer conduit 110 extends through the top surface 108 of the mold structure 106. In other examples, the mold structure 106 may extend over the top of the heat transfer tube 110, thereby encapsulating the heat transfer tube 110.

In some examples, the mold structure 106 may include shielding nanoparticles dispersed in or otherwise combined with a base mold compound, e.g., as discussed above with respect to fig. 1. For example, shielding nanoparticles may include magnetic shielding nanoparticles for shielding the die 102 from magnetic fields, and/or radiation shielding nanoparticles for shielding the die 102 from ionizing radiation. Exemplary magnetic shielding nanoparticles and exemplary radiation shielding nanoparticles are listed above.

Fig. 4 is a cross-sectional side view illustrating an exemplary IC package 400 formed as a Ball Grid Array (BGA) package. The exemplary BGA package 400 includes a die 102 mounted on a substrate 404 (e.g., a B-T epoxy substrate). The die 102 may be mounted face up on a die pad 406 formed on the top side of the substrate 404. The die 102 may be connected to circuitry formed on or in the substrate by respective bond wires 408. Solder balls 410 may be formed on the bottom side of the substrate 404 for mounting the IC package 400 to a PCB or other structure.

As shown, the heat transfer conduit 110 may be formed on the die 102 at selected locations or areas on the die 102 using any suitable process, for example, using an additive printing process (e.g., a 2D, 2.5D, or 3D printer) or other process disclosed herein. The heat transfer conduit 110 may be formed from a thermally conductive compound 112 comprising thermally conductive nanoparticles dispersed in a base compound (e.g., epoxy), for example, as described above. The die 102 may be encapsulated by a mold structure 106 formed over a substrate 404. As shown, the mold structure 106 may be formed such that the distal surface 118 of the heat transfer conduit 110 extends through the top surface 108 of the mold structure 106. In other examples, the mold structure 106 may extend over the top of the heat transfer tube 110, thereby encapsulating the heat transfer tube 110.

Fig. 5 is a cross-sectional side view illustrating an exemplary IC package 500 formed as a flip-chip pBGA (FC-pBGA) package. The exemplary flip-chip PBGA package 500 includes a die 102 flip-chip mounted on a substrate 504 by solder ball mounting with an epoxy underfill 506. Solder balls 510 may be formed on the bottom side of the substrate 504 for mounting the IC package 500 to a PCB or other structure.

As shown, the heat transfer conduit 110 may be formed on the (flip-chip mounted) die 102 at selected locations or areas on the die 102 using any suitable process, for example, using an additive printing process (e.g., a 2D, 2.5D, or 3D printer) or other process disclosed herein. The heat transfer conduit 110 may be formed from a thermally conductive compound 112 comprising thermally conductive nanoparticles dispersed in a base compound (e.g., epoxy), for example, as described above. The die 102 may be encapsulated by a mold structure 106 formed over a substrate 504. As shown, the mold structure 106 may be formed such that the distal surface 118 of the heat transfer conduit 110 extends through the top surface 108 of the mold structure 106. In other examples, the mold structure 106 may extend over the top of the heat transfer tube 110, thereby encapsulating the heat transfer tube 110. In some examples, the mold structure 106 may include shielding nanoparticles, e.g., magnetic shielding nanoparticles and/or radiation shielding nanoparticles, as described above.

Fig. 6 is a cross-sectional side view illustrating an exemplary IC package 600 including a first die 102a and a second die 102b, such as a Field Programmable Gate Array (FPGA) and a Power Management IC (PMIC), mounted on an interposer 604. A first heat transfer conduit 110a is formed on the first die 102a and a second heat transfer conduit 110b is formed on the second die 102 b. The heat transfer conduits 110a and 110b may be formed at heat generating locations identified on the respective dies 102a and 102b, respectively, for example, as determined based on thermal analysis of the IC package 600 (or a similar IC package).

In the example shown, a radiation shielding layer (or encapsulation structure) 612 is formed over the second die 102b (e.g., the PMIC die), but not over the FPGA die, to shield the second die 102b from ionizing radiation. The radiation shielding layer 612 may include radiation shielding nanoparticles, e.g., boron Nitride (BN), bismuth (Bi), bismuth oxide (Bi) ₂ O ₃ ) Tantalum nitride (TaN), tungsten nitride (W) ₃ N ₂ ) Tin oxide (SnO) ₂ ) Copper (I) oxide (Cu) ₂ O) or copper (II) oxide (CuO) nanoparticles. A mold compound 620 is formed over the two dies 102a and 102b and over the radiation shield 612 formed over the second die 102 b. In some examples, the mold compound 620 may include magnetically shielding nanoparticles, e.g., a mu-metal or Fe ₂ O ₃ Nanoparticles for shielding both the first die 102a and the second die 102b from the magnetic field.

Fig. 7 is a cross-sectional side view illustrating an exemplary electronic device 700 including the exemplary IC package 300 (leadframe package) shown in fig. 3 mounted on a package support structure (e.g., PCB 702). As discussed above with respect to fig. 3, the exemplary leadframe package 300 includes: a leadframe 304 including a die attach pad 306 and a plurality of lead fingers 308; a die 102 mounted on the die attach pad 306 and connected to selected lead fingers 308 by respective bond wires 314; a heat transfer conduit 110 formed on the die 102; and a mold structure 106 that extends above and below the die attach pad 306 and encapsulates the die 102. As described above, the heat transfer conduit 110 may be formed from a thermally conductive compound 112 that includes thermally conductive nanoparticles 114 dispersed in a base compound 116 (e.g., epoxy). In addition, the mold structure 106 may include shielding nanoparticles, for example, shielding nanoparticles for shielding the die 102 from magnetic fields and/or radiation shielding nanoparticles for shielding the die 102 from ionizing radiation.

As shown in fig. 7, the exemplary electronic device 700 includes an upper shield 720 on the top side of the PCB 702 and a lower shield 730 on the back side of the PCB 702. In the example shown, the upper shield layer 720 includes a first upper shield layer 722 formed over the leadframe package 300 and a second upper shield layer 724 formed over the first upper shield layer 722. Each upper shielding layer 722 and 724 may include shielding nanoparticles (e.g., magnetic shielding nanoparticles and/or radiation shielding nanoparticles) dispersed in or otherwise combined with a base compound (e.g., an epoxy or other polymer). Exemplary magnetic shielding nanoparticles and exemplary radiation shielding nanoparticles are listed above with reference to fig. 1.

In some examples, the upper shielding layers 722 and 724 may include different types or different concentrations of shielding nanoparticles. For example, the upper shield layer 722 may include magnetic shielding nanoparticles (e.g., for shielding the die 102 from magnetic fields), the upper shield layer 724 may include radiation shielding nanoparticles (e.g., for shielding the die 102 from ionizing radiation), or vice versa. As another example, the upper shield layers 722 and 724 may include the same type of nanoparticles (e.g., magnetic shielding nanoparticles or radiation shielding nanoparticles), but with correspondingly different concentrations of nanoparticles, thereby defining a shield gradient in a direction toward or away from the die 102. For example, the upper shield layers 722 and 724 may provide a greater degree of shielding in a direction toward the die 102 (e.g., where the upper shield layer 722 provides a greater degree of shielding than the upper shield layer 724).

Similarly, the lower shielding layers 732 and 734 may include shielding nanoparticles (e.g., magnetic shielding nanoparticles and/or radiation shielding nanoparticles) dispersed in or otherwise combined with a base compound (e.g., an epoxy or other polymer). As with the upper shield layers 722 and 724, the lower shield layers 732 and 734 may include different types or concentrations of shielding nanoparticles, for example, which may define a shielding gradient.

Fig. 8 is a cross-sectional side view illustrating an exemplary electronic device 800 including a first (lower) die 802a and a second (upper) die 802b arranged in a stacked manner on a PCB 804 and separated from each other by an insulating layer 806, wherein the second (upper) die 802b generates more heat than the first (lower) die 802 a. A heat transfer conduit 810 is formed over the two dies 802a and 802b to remove heat generated by the two dies 802a and 802 b. As shown, the heat transfer conduit 810 may cover a larger area of the second die 802b than the first die 802a in order to provide additional heat transfer from the hotter second die 802 b. For example, (b) the contact area between the heat transfer conduit 810 and the second die 802b and (b) the contact area between the heat transfer conduit 810 and the first die 802a may be proportional to or correspond to the relationship between the heat generated by the second die 802b and the heat generated by the first die 802 a.

In some examples, the heat transfer conduit 810 formed on the dies 802a and 802b may include a single droplet or several droplets of the thermally conductive compound 112, e.g., formed by a 2D, 2.5D, or 3D printer or nozzle-based injection molding, e.g., as described above. Forming a single heat transfer conduit over multiple die may save costs and may have a more compact design, e.g., use a smaller footprint, than forming different heat transfer conduits over individual die.

As shown in fig. 8, a mold structure 812 may be formed over the first die 802a and the second die 802 b. Heat sink 820 may be formed over mold structure 812 and thermally coupled to heat transfer conduit 810 to facilitate heat transfer away from second die 802 b.

Fig. 9 is a flow chart illustrating an exemplary method 900 for forming an integrated circuit package. At 902, a die is mounted on a die carrier. At 904, thermally conductive nanoparticles and (optionally) silica particles are mixed with a base polymer (e.g., an epoxy resin) to form a thermally conductive compound. At 906, the heat transfer conduit is formed on the die using a thermally conductive compound, for example, printed using a 2D, 2.5D, or 3D printer. At 908, a mold structure is formed that at least partially encapsulates the die. In some examples, the mold structure may include shielding nanoparticles (e.g., magnetic shielding nanoparticles and/or radiation shielding nanoparticles), e.g., as described above.

Optionally, at 910, at least one magnetic shielding layer is formed, e.g., comprising a mu-metal or hematite (Fe ₂ O ₃ ). Optionally, at 912, at least one radiation shielding layer is formed, e.g., comprising Boron Nitride (BN), bismuth (Bi), bismuth oxide (Bi ₂ O ₃ ) Tantalum nitride (TaN), tungsten nitride (W) ₃ N ₂ ) Tin oxide (SnO) ₂ ) Copper (I) oxide (Cu) ₂ O) or copper (II) oxide (CuO). Optional steps 910 and 912 may be performed in any order.

FIG. 10 is a flow chart illustrating an exemplary method 1000 for analyzing and adjusting the position of a heat transfer conduit. At 1002, a first IC package includes a first IC die mounted on a first die carrier, and a mold structure is formed over the mounted first IC die. In operation, thermal analysis of the first IC package is performed at 1004, for example, thermal scanning of the first IC package using an Infrared (IR) camera. At 1006, a first conduit location is determined based on a thermal analysis of the first IC package. For example, the thermal tensor flow module may analyze the thermal scan performed at 1004 and generate a thermal model to identify a first location for forming the heat transfer conduit. At 1008, a second IC package is formed on the second IC die at the determined first conduit location, including the first heat transfer conduit (e.g., using an additive printing process). The second IC die is a second instance of the first IC die.

In operation, thermal analysis of the second IC package is performed at 1010, for example, thermal scanning of the second IC package using an Infrared (IR) camera. At 1012, a second conduit location (e.g., different from the first conduit location) is determined based on a thermal analysis of the second IC package, e.g., using a thermal tensor flow module to analyze the thermal scan performed at 1010 and generate a thermal model to identify the second location for forming the heat transfer conduit. At 1014, a third IC package is formed on the third IC die at the determined second conduit location, including the second heat transfer conduit (e.g., using an additive printing process). The third IC die is a third example of the first IC die. The process may continue, for example, in an iterative fashion to identify a target location for the heat transfer conduit for improved thermal performance.

Claims

1. An electronic device, comprising:

an integrated circuit package, the integrated circuit package comprising:

a die mounted on a die carrier;

a mold structure at least partially encapsulating the mounted die; and

a heat transfer conduit formed on the die and extending at least partially through the mold structure to transfer heat away from the die;

Wherein the heat transfer conduit is formed from a thermally conductive compound comprising thermally conductive nanoparticles.

2. The electronic device defined in claim 1 wherein the heat transfer conduit extends through the entire thickness of the mold structure with a distal surface of the heat transfer conduit exposed through an outer surface of the mold structure.

3. The electronic device of any of claims 1-2, wherein the die carrier comprises a leadframe or interposer.

4. The electronic device of any of claims 1-3, wherein the thermally conductive nanoparticles comprise at least one of: diamond nanoparticles, silicon carbide nanoparticles, boron nitride nanoparticles, hexagonal boron nitride nanoparticles, or boron nitride nanotubes.

5. The electronic device of any of claims 1-4, wherein the thermally conductive compound comprises thermally conductive nanoparticles dispersed in a polymer resin.

6. The electronic device of any of claims 1-4, wherein the thermally conductive compound comprises thermally conductive nanoparticles and silica dispersed in an epoxy resin.

7. The electronic device of any of claims 1-6, wherein the mold structure comprises magnetically shielded nanoparticles to shield the die from a magnetic field.

8. The electronic device of claim 7, wherein the magnetically shielded nanoparticles comprise a mu-metal or hematite (Fe ₂ O ₃ ) At least one of them.

9. The electronic device of any of claims 1-8, wherein the mold structure includes radiation-shielding nanoparticles to shield the die from ionizing radiation.

10. The electronic device of claim 9, wherein the shielding nanoparticles comprise at least one of: boron Nitride (BN), bismuth (Bi), bismuth oxide (Bi) ₂ O ₃ ) Tantalum nitride (TaN), tungsten nitride (W) ₃ N ₂ ) Tin oxide (SnO) ₂ ) Copper (I) oxide (Cu) ₂ O) or copper (II) oxide (CuO).

11. The electronic device of any of claims 1-10, comprising a shielding layer formed over the mold structure, the shielding layer comprising at least one of: (a) Magnetic shielding nanoparticles for shielding the die from magnetic fields; or (b) radiation shielding nanoparticles for shielding the die from ionizing radiation.

12. The electronic device of any of claims 1-11, comprising a multi-layer shield formed over the mold structure, wherein the multi-layer shield comprises a plurality of different shield layers, wherein each shield layer of the plurality of different shield layers comprises shielding nanoparticles to shield the die from at least one of magnetic field or ionizing radiation, wherein the plurality of different shield layers comprises different types or concentrations of shielding nanoparticles.

13. The electronic device of any of claims 1-12, wherein the different types or concentrations of shielding nanoparticles in the plurality of different shielding layers of the multi-layer shield define a shielding gradient.

14. The electronic device of any of claims 1-13, wherein:

the integrated circuit package is mounted on a first side of a package support structure; and is also provided with

The electronic device includes a backside shielding layer formed on a second side of the package support structure opposite the first side, the backside shielding layer including shielding nanoparticles to shield the die from at least one of magnetic field or ionizing radiation.

15. A method, comprising:

forming an integrated circuit package, the integrated circuit package comprising:

mounting a die on a die carrier;

forming a heat transfer conduit over the die;

forming a mold structure at least partially encapsulating the die;

wherein the heat transfer conduit extends at least partially through the mold structure; and is also provided with

Wherein the heat transfer conduit includes thermally conductive nanoparticles to transfer heat away from the die.

16. The method of claim 15, comprising:

Forming a thermally conductive compound comprising mixing (a) silica particles and (b) thermally conductive nanoparticles with a polymer; and

the heat transfer conduit is formed from the thermally conductive compound.

17. The method of claim 15, comprising:

forming a thermally conductive compound comprising:

mixing a surfactant with the thermally conductive nanoparticles to form surfactant-coated thermally conductive nanoparticles; and

mixing the surfactant-coated thermally conductive nanoparticles with a polymer; and

the heat transfer conduit is formed from the thermally conductive compound.

18. The method of claim 15, comprising:

forming a thermally conductive compound comprising:

mixing (a) the surfactant-coated thermally conductive nanoparticles and (b) a silica filler with an epoxy resin; and

the heat transfer conduit is formed from the thermally conductive compound.

19. The method of claim 15, wherein forming the thermally conductive compound comprises mixing silica particles and thermally conductive nanoparticles with an epoxy, wherein the thermally conductive nanoparticles comprise diamond nanoparticles, silicon carbide nanoparticles, boron nitride nanoparticles, hexagonal boron nitride nanoparticles, or boron nitride nanotubes.

20. The method of any of claims 15-19, wherein forming the heat transfer conduit on the die comprises printing the heat transfer conduit using an additive printing process.

21. The method according to any one of claims 15 to 20, comprising:

mixing the shielding nanoparticles with a mold compound to form a nanoparticle-reinforced mold compound; and

the mold structure is formed from the nanoparticle reinforced mold compound.

22. The method of any of claims 15 to 21, comprising forming a shielding layer over the mold structure, the shielding layer comprising at least one of: (a) Magnetic shielding nanoparticles for shielding the die from magnetic fields; or (b) radiation shielding nanoparticles for shielding the die from ionizing radiation.

23. The method of any of claims 15-22, comprising forming a plurality of different shielding layers over the mold structure, wherein each shielding layer of the plurality of different shielding layers comprises shielding nanoparticles to shield the die from at least one of magnetic field or ionizing radiation, wherein the plurality of different shielding layers comprises different types or concentrations of shielding nanoparticles.

24. A method, comprising:

forming a first integrated circuit package, the first integrated circuit package comprising:

mounting a first integrated circuit die; and

forming a mold structure at least partially encapsulating the first integrated circuit die;

thermally analyzing the first integrated circuit package; and

forming a second integrated circuit package, the second integrated circuit package comprising:

determining a first conduit location based on the thermal analysis of the first integrated circuit package; and

a first heat transfer conduit is formed on the second integrated circuit die at the determined first conduit location.

25. The method of claim 24, comprising:

thermally analyzing the second integrated circuit package; and

forming a third integrated circuit package, the third integrated circuit package comprising:

determining a second conduit location different from the first conduit location based on the thermal analysis of the second integrated circuit package; and

a second heat transfer conduit is formed on the third integrated circuit die at the determined second conduit location.

26. A device formed by the method of any one of claims 15 to 25.