Multi-package module and electronic device using the same

A package substrate for a multi-package module. The package substrate comprises a substrate having a die region and at least one thermal channel region outwardly extending to an edge of the substrate from the die region. An array of bumps is arranged on the substrate except in the die and thermal channel regions, in which the interval between the bumps is narrower than the width of the thermal channel region. An electronic device with a package substrate is also disclosed.

BACKGROUND

The invention relates to an electronic package and in particular to a package substrate for multi-package module for thermal dissipation and an electronic device using the same.

Demand for small, high performance portable electronic products such as cell phones, mobile computers, and the like have driven the industry to increase integration on individual semiconductor dice. Accordingly, the industry is achieving high integration by turning to 3D packaging by combining assembly technologies including wire bonding or flip chip to stack die packages to form a multi-package module (MPM).

MPM, a current assembly technology, integrates different functions of dice, such as microprocessors or memory, logic, optic ICs, instead of placing individual packages onto a large printed circuit board (PCB). MPM, however, has a much higher power density than an individual single die package. Thus, thermal management is a key factor in its successful development.

FIG. 1illustrates a conventional electronic device100with an MPM. The electronic device100comprises a MPM20mounted on a PCB101and comprising a package substrate12. The upper and lower surfaces of the package substrate12have dice16and14with different functions thereon, respectively, to create the MPM20. For example, the die16is mounted on the upper surface of the package substrate12by bumps (or solder balls) of a package substrate12′. The die14is mounted on the lower surface of the package substrate12by flip chip. The lower surface of the package substrate12comprises a plurality of bumps10thereon to correspondingly connect to the bonding pads (not shown) on the PCB101. In the MPM20, heat generated from the die16can be dissipated by radiation and convection. The gap g between the die14and the PCB101is too narrow, however, to dissipate the heat generated from thereof by radiation and convection. Accordingly, the heat generated from the die14is dissipated by conduction only. Typically, a metal layer102is disposed on the PCB101corresponding to the die14and connected to the die14by a heat conductive paste22. That is, thermal dissipation is accomplished by a thermal conductive path created by the heat conductive paste22, the metal layer102and the PCB101.

Passive cooling, however, cannot provide adequate thermal dissipation at a higher rate for high power dice which may generate higher heat. That is generated heat cannot be rapidly dissipated from dice by conducting the heat to the PCB through the heat conductive paste and the metal layer.

SUMMARY

A package substrate for multi-package module and an electronic device using the same are provided. An embodiment of a package substrate for a multi-package module comprises a substrate having a die region and at least one thermal channel region outwardly extending to an edge of the substrate from the die region. An array of bumps is arranged on the substrate except in the die and thermal channel regions, wherein the interval between the bumps is narrower than the width of the thermal channel region.

An exemplary embodiment of an electronic device comprises a package substrate, comprising a substrate having a die region and at least one thermal channel region outwardly extending to an edge of the substrate from the die region and an array of bumps arranged on the substrate except in the die and thermal channel regions. A circuit board comprises a plurality of bonding pads correspondingly connecting to the bumps. A heat sink is disposed between the circuit board and the package substrate, comprising a first portion corresponding to the die region and a second portion adjacent to the first portion, extending to the circuit board outside the package substrate along the thermal channel region.

An embodiment of an electronic device, additionally, comprises a package substrate, comprising a substrate having a die region and at least one thermal channel region outwardly extending to an edge of the substrate from the die region and an array of bumps arranged on the substrate except in the die and thermal channel regions. A circuit board comprises a plurality of bonding pads correspondingly connecting to the bumps and a metal layer underlying the package substrate. The metal layer comprises a first portion corresponding to the die region, a second portion adjacent to the first portion, extending to the circuit board outside the package substrate along the thermal channel region and a third portion adjacent to the end of the second portion.

DETAILED DESCRIPTION

A package substrate for multi-package module (MPM) and an electronic device using the same will now be described in greater detail.

FIGS. 2A and 2Billustrate an exemplary embodiment of an MPM, whereinFIG. 2Ais a bottom plane view of the MPM andFIG. 2Bis a cross-section along line2B-2B ofFIG. 2A. The MPM40comprises a package substrate32. The lower surface of the package substrate32has a die region32aand at least one thermal channel region32band the upper surface of the package substrate32also has a die region (not shown). Here, the lower surface represents a surface facing the surface of a circuit board, such as a printed circuit board (PCB) and the upper surface represents the surface opposite to the lower surface. In this embodiment, the package substrate32may comprise plastic, ceramic, inorganic or organic material. Typically, the die region32ais substantially at the center of the package substrate32. Unlike the conventional package substrate, the package substrate32comprises at least one thermal channel region32boutwardly extending to an edge of the package substrate32from the die region32a. In some embodiments, the thermal channel region32bmay extend to an opposite edge of the package substrate32across the die region32a, as shown inFIG. 2C. It will be apparent to those skilled in the art that the package substrate32may comprise one or more thermal channel regions extending to the edges of the package substrate32along different directions from the die region32aand it is to be understood that the invention is not limited toFIGS. 2A and 2C.

Dice34and36with different functions may be respectively mounted in the die region32aof the lower surface and that of the upper surface of the package substrate32by the same or different electronic packages. For example, dice34and36may respectively be mounted on the package substrate32by flip chip or wire bonding.

An array of bumps30, such as metal bump, solder balls, signal balls or the like, is arranged on the lower surface of the package substrate32except in the die region32aand the thermal channel region32b, to transport signals to external circuits from the dice34and36. The interval between the bumps30is narrower than the width of the thermal channel region32b.

FIGS. 3A and 3Billustrate an embodiment of an electronic device with an MPM of the invention, whereinFIG. 3Ais a bottom plane view of the electronic device andFIG. 3Bis a cross-section along line3B-3B ofFIG. 3A, and the same reference numbers asFIGS. 2A and 2Bare used, wherefrom like descriptions are omitted. The electronic device200comprises MPM40, a circuit board201and a heat sink203. As mentioned, the MPM40comprises a package substrate32and dice34and36. The package substrate32comprises an array of bumps30arranged on the lower surface of the package substrate32except in the die region32an and the thermal channel region32b. Dice34and36are respectively disposed on the die region32aof the lower surface and that of the upper surface of the package substrate32.

A circuit board201, such as a PCB, comprises a plurality of bonding pads202correspondingly connected to the bumps30, thereby electronically connecting the circuit board201and the dice34and36. Typically, the circuit board201comprises at least one or more metal layers and at least one or more insulating layers, in which the metal layer may serve as a signal layer, a power layer, and/or a grounding layer. In order to simplify the diagram, a flat substrate is depicted.

A heat sink203is disposed on the circuit board201and between the circuit board201and the package substrate32, comprising first and second portions204and206. The first portion204corresponds to the die region32aand connected to the die34by a heat conductive paste42. The second portion206is adjacent to the first portion204and extends outside the package substrate32along the thermal channel region32b. In this embodiment, the heat sink203comprises gold, silver or copper. Moreover, the first portion204of the heat sink203may partially or fully overlap the die34. Here, only an example of the full overlap is depicted. Note that the shape of the heat sink203may be varied with the design of the thermal channel region32b.

A thermal dissipation module208is disposed on the second portion206of the heat sink203outside the package substrate32, providing an active thermal dissipation. In this embodiment, the thermal dissipation module208may comprise a fan207and an underlying heat dissipating component205, such as a heat plate or pipe.

According to the electronic device200of the invention, the thermal channel region32bcan be formed by rearranging the bumps30. Moreover, since the heat sink203may extend outside the package substrate32along the thermal channel region32b, the heat generated from the die34on the lower surface of the package substrate32can be effectively and rapidly dissipated, to the ambient environment by radiation, convection and conduction, as shown by the arrows inFIG. 3B. Additionally, if the die34is a high power die, the heat can be dissipated quickly by the fan207. Compared to conventional thermal dissipation by conduction of the circuit board, the electronic device200with MPM40of this embodiment has better thermal dissipation and a higher thermal dissipation rate.

FIGS. 4A and 4Billustrate an embodiment of an electronic device with an MPM, whereinFIG. 4Ais a bottom plane view of the electronic device andFIG. 4Bis a cross-section along line4B-4B ofFIG. 3A. The same reference numbers asFIGS. 3A and 3Bare used, wherefrom like descriptions are omitted. Unlike the embodiment ofFIGS. 3A and 3B, the thermal conductive path is formed by defining a metal layer209of the circuit board201. In this embodiment, the metal layer209comprises a first portion210, a second portion212and a third portion214. The first portion210of the metal layer209corresponds to the die region32aand is connected to the die34by a heat conductive paste42. The second portion212of the metal layer209is adjacent to the first portion210and extends outside the package substrate32along the thermal channel region32b. The third portion214of the metal layer209is adjacent to the end of the second portion212. The first and second portions210and212of the metal layer209serve as a heat sink to conduct heat generated from the die34outside the package substrate32. The third portion214of the metal layer209serves as a heat dissipating component to dissipate heat to the ambient environment by a fan207disposed thereon, as shown by the arrows inFIG. 4B.

In this embodiment, since the metal layer209may extend outside the package substrate32along the thermal channel region32b, the heat generated from the die34on the lower surface of the package substrate32can be effectively and rapidly dissipated to the ambient environment by radiation, convection and conduction. Compared to the conventional thermal dissipation by conduction of the circuit board, the electronic device200with MPM40has better thermal dissipation and a higher thermal dissipation rate. Moreover, since the metal layer209is included in the circuit board201, no additional heat sink and heat dissipating component are required.