JPH11121660A - Semiconductor device and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device and its manufacturing method which is capable of effective thermal diffusion, even when there is no spatial margin for equipping a heat radiating fan. SOLUTION: A semiconductor device comprises a gold bump (metallic bump) 2 on a surface of an LSI chip (semiconductor chip) 1 which is electrically connected with a surface of a package substrate 3 of a solder bump 4 on a rear surface of the package substrate 3 which is electrically connected with a mounting substrate 5. A heat-radiating body 6 is made to contact a rear surface of the LSI chip 1 via a thermal conductive medium 7, and a part of the heat- radiating body 6 is fixed on the mounting substrate 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly, to a semiconductor device such as a semiconductor integrated circuit device capable of efficiently diffusing heat even when there is not enough space for attaching a radiation fin. And a method of manufacturing the same.

[0002]

2. Description of the Related Art The present inventors have studied a mounting technique for a semiconductor integrated circuit device. The following is a technique studied by the present inventors, and the outline is as follows.

That is, a recent LSI (Large Scale In)
In a semiconductor integrated circuit device such as an integrated circuit, when used in a workstation or a personal computer, it is necessary to improve the performance and increase the number of pins, so that a BGA (Ball Grid Array) or a CSP (Chip Size) is required.
Package).

In this case, in the flip-chip type BGA or CSP, since the back surface of the LSI chip faces the opposite side to the mounting substrate, when a high-heat-generating LSI chip is mounted, the back surface of the LSI chip is used for heat dissipation. Fins (radiation fins) are mounted.

Further, by adjusting the shape of the fins or the flow rate of air for cooling, it is possible to cool LSI chips having various heat values.

As a document describing a BGA type package as an LSI package, for example, see “Nikkei Electronics August 2, 1993,” p.
04.

[0007]

However, in the above-described package structure, when sufficient space cannot be secured above the package mounting portion of the mounting board, such as in a portable device or a thin device, or when fins for heat radiation cannot be used. If not, there is a problem that heat cannot be sufficiently released.

Further, for example, even if the back surface of a chip such as an LSI chip is exposed, the area of the back surface of the chip is small, so that heat dissipation by heat transfer to the surrounding air cannot be expected.

On the other hand, in the case of a flip chip, heat is radiated to the mounting substrate by heat conduction through a bump as an electrode at the lower part of the chip, a package substrate, and further through a package substrate electrode at the lower part of the package substrate. In general, due to the large thermal resistance,
There is a problem that the heat generated in the chip cannot be sufficiently diffused.

As a result, in the above-described package structure, it is not possible to mount a chip generating a large amount of heat.

An object of the present invention is to provide a semiconductor device capable of efficiently dispersing heat even when there is no space for mounting a radiation fin, and a method of manufacturing the same.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0013]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, the semiconductor device of the present invention is an LSI
A semiconductor device in which metal bumps on the surface of a semiconductor chip such as a chip are electrically connected to the surface of the package substrate, and solder bumps on the back surface of the package substrate are electrically connected to the mounting substrate. The heat sink is in contact with the back surface of the semiconductor chip via a heat conductive medium, and a part of the heat radiator is fixed to the mounting substrate.

Further, a method of manufacturing a semiconductor device according to the present invention
After electrically connecting the metal bumps on the surface of the semiconductor chip to the surface of the package substrate, electrically connecting the solder bumps on the back surface of the package substrate to the mounting substrate; and providing a heat conductive medium on the back surface of the semiconductor chip. And a step of fixing the heat radiator to the mounting substrate while contacting the heat radiator to the rear surface of the semiconductor chip via a heat conductive medium with the heat radiator mounted on the back surface of the semiconductor chip.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, components having the same function are denoted by the same reference numerals, and redundant description will be omitted.

(First Embodiment) FIG. 1 is a schematic sectional view showing a semiconductor device according to a first embodiment of the present invention.

In the semiconductor device of the present embodiment, a gold bump (metal bump) on the surface of an LSI chip (semiconductor chip) 1 is used.
2 is a semiconductor device that is electrically connected to the front surface of the package substrate 3, and the solder bumps 4 on the back surface of the package substrate 3 are electrically connected to the mounting substrate 5. Of the radiator 6 is fixed to the mounting board 5 with a heat conductive medium 7 in contact with the rear surface of the radiator 6.

Also, in the semiconductor device of the present embodiment, in the region where a part of the heat radiator 6 is fixed to the mounting substrate 5, the ground conductive layer 5a and the heat radiator 6 of the mounting substrate 5 are connected to the through hole 5b. Conductive layer 5c embedded in
Are electrically connected via

In the method of manufacturing a semiconductor device according to the present embodiment, after the gold bumps 2 on the surface of the LSI chip 1 are electrically connected to the surface of the package substrate 3,
Electrically connecting the solder bumps 4 on the back surface of the LSI chip 1 to the mounting substrate 5, and providing a heat conductive medium 7 on the back surface of the LSI chip 1, and dissipating the heat while placing the radiator 6 on the back surface of the LSI chip 1. A step of bringing the body 6 into contact with the back surface of the LSI chip 1 via the heat conductive medium 7 and fixing (attaching) the heat radiator 6 to the mounting board 5.

Next, the semiconductor device of the present embodiment and a method of manufacturing the same will be described in detail.

That is, an LSI chip (semiconductor chip)
Gold bumps (metal bumps) 2 are arranged on electrode surfaces for bonding in advance on the surface of 1. In this case, after a gold wire as a bonding wire is attached to a bonding electrode terminal on the surface of the LSI chip 1, heat treatment is performed, and a gold bump (metal bump) 2 is formed using the gold wire as a bump-shaped electrode. doing.

The package substrate 3 has, for example, a multilayer wiring structure (planar) including a ground (ground) conductive layer, a power supply conductive layer, a signal conductive layer and the like in an inner layer of a base material made of the same material as that of the printed circuit board. Layered structure of wire-like wiring)
Wiring layer. Also, on the chip surface side of the package substrate 3, facing the gold bump 2 of the LSI chip 1,
Electrode terminals are formed, and solder bumps 4 as electrode terminals for electrically connecting to the mounting substrate 5 are provided on the mounting substrate mounting surface side of the package substrate 3. Further, in the package substrate 3, the electrode terminals on the chip surface side and the electrode terminals on the mounting substrate mounting surface side are the conductive layers in which the corresponding electrode terminals are embedded in through holes provided in the base material. Are electrically connected via

The gold bumps 2 on the surface of the LSI chip 1 are electrically connected to electrode terminals on the surface of the package substrate 3 by a conductive adhesive.

The space between the surface of the LSI chip 1 and the surface of the package substrate 3 is filled with a resin (not shown), and the space between the surface of the LSI chip 1 and the surface of the package substrate 3 and the surface of the LSI chip 1 and the surface of the package are filled. Substrate 3
The gold bumps 2 and the like, which are electrical connections between the surface and the like,
Protected from external forces and pollution.

Solder bumps 4, which are solder ball electrodes, are electrically connected to the electrode terminals on the back surface of the package substrate 3.

The mounting substrate 5 has a multi-layer wiring structure (a planar wiring layer) including a ground conductive layer, a power supply conductive layer, a signal conductive layer, and the like in an inner layer of a base material made of the same material as that of the printed circuit board, for example. Wiring layer). Further, on the surface of the mounting substrate 5, electrode terminals electrically connected to chip components such as a package, a resistor and a capacitor are provided. In this case, a solder paste is supplied to the component mounting electrode terminals in advance by a screen printing method, and the package substrate 3 and the chip component are positioned at predetermined positions and mounted.
A heat treatment of 0 ° C. is performed to melt the solder, and
Each component is fixed to the electrode terminal on the surface of the device.

When fixing the radiator 6 to the mounting substrate 5,
A state in which a heat conductive medium 7 made of, for example, grease (resin) to which alumina as a filler is added is applied to the back surface of the LSI chip 1 mounted on the package substrate 3, and then the radiator 6 is placed so as to cover from above. Are fixed to the mounting substrate 5. In this case, the material of the heat transfer medium 7 is
Various materials can be applied, but by using grease to which alumina is added as a filler, the heat conductive medium 7 having good heat conductivity can be obtained. In addition, as another embodiment of the heat conduction medium 7, a sheet-like heat conduction sheet (resin) in which a filler is dispersed can be used. The heat conductive medium 7 is a resin made of grease in which particles such as alumina having a high thermal conductivity are dispersed as a filler or a heat conductive sheet in which a filler is dispersed. Can be buried, so that heat can be conducted efficiently.

When the heat radiator 6 is fixed to the mounting substrate 5, solder as an adhesive 8 is supplied to the surface of the mounting substrate 5 in a region where the heat radiator 6 is fixed, and the heat radiator 6 is mounted. After alignment with the substrate 5, the heater is locally heated to melt the solder, and the radiator 6 is fixed to the mounting substrate 5 using an adhesive 8 made of solder. In addition,
As another mode for fixing the heat radiator 6 to the mounting substrate 5, in addition to using solder, using an adhesive having good heat conductivity or applying a mode of mechanical fixing using screws or the like is applied. Can be.

The heat radiator 6 is made of a metal such as copper and has a plate shape with a thickness of 0.1 to 0.5 mm. The contact portion 6b on the back surface of the chip of the heat radiator 6 has a flat shape. 6
The mounting portion 6a has a bent shape. As a result of the study by the present inventor, it has been clarified that when the material of the heat radiator 6 is copper, aluminum, a copper alloy or an aluminum alloy, the heat radiation is improved. Therefore, since the heat radiator 6 is made of a material having a high thermal conductivity, heat can be efficiently conducted, and the heat generated from the LSI chip 1 is efficiently conducted to the mounting board 5. be able to.

In the heat radiator 6, the bent attachment portion 6a of the heat radiator 6 is formed in the two sides of the flattened chip back surface contact portion 6b of the heat radiator 6, or in the three sides. The embodiment is formed in four sides. Further, when the heat radiator 6 is fixed to the mounting substrate 5, the heat radiator 6
The two or three or four sides of the bent-shaped mounting portion 6a may be used.

According to the semiconductor device of the present embodiment described above, the heat radiator 6 is provided on the back surface of the LSI chip 1 by the heat conductive medium 7.
Since a part of the heat radiator 6 is fixed to the mounting substrate 5, the heat generated in the LSI chip (semiconductor chip) 1 is dissipated through the heat conductive medium 7. Is transferred to the mounting board 5 in the low temperature state, and the heat generated from the LSI chip 1 is transferred to the LS.
It can be removed from the I chip 1 in an excellent condition.

According to the semiconductor device of the present embodiment, the heat radiator 6 is provided on the back surface of the LSI chip 1 by the heat conductive medium 7.
And a part of the heat radiator 6 is fixed to the mounting substrate 5, so that the mounting substrate 5
Since the surface area is larger than that of the chip 1 and the package substrate 3 and the heat transfer to the air can be performed with a very small resistance state, the heat generated from the LSI chip 1 can be removed from the LSI chip 1 in an excellent state.

Further, according to the semiconductor device of the present embodiment, the radiator 6 is connected to the ground conductive layer 5 on the mounting board 5.
a, the ground conductive layer 5a in the mounting board 5 is a conductive layer having a high wiring density and a high wiring density, so that heat is efficiently diffused in the mounting board 5, LS generated heat from chip 1
It can be removed from the I chip 1 in an excellent condition.

Therefore, according to the semiconductor device of the present embodiment, it is possible to mount the LSI chip (semiconductor chip) 1 with high heat generation on the package substrate 3 or the like.

According to the semiconductor device of the present embodiment, the radiator 6 is connected to the ground conductive layer 5 on the mounting substrate 5.
a, the radiator 6 is connected to L
Even in a mode in which the SI chip 1 and the package substrate 3 are completely covered, an electromagnetic wave shielding effect can be obtained.
A mounting structure with little influence on EMI (electromagnetic interference) can be obtained.

In the semiconductor device of the present embodiment, gold bumps (metal bumps) on the surface of an LSI chip (semiconductor chip) 1 are used.
2 is a semiconductor device that is electrically connected to the front surface of the package substrate 3, and the solder bumps 4 on the back surface of the package substrate 3 are electrically connected to the mounting substrate 5. Is provided with a flip-chip type BGA or CSP package structure because a part of the heat radiator 6 is fixed to the mounting substrate 5 through the heat conductive medium 7. To various semiconductor devices such as a semiconductor integrated circuit device.

Therefore, the semiconductor device according to the present embodiment is used when a sufficient space cannot be ensured above the package mounting portion of the mounting substrate 5 or when a heat dissipating fin cannot be used, such as a portable device or a thin device. In this case, since heat can be sufficiently dissipated, the present invention can be applied to a device in which an LSI chip (semiconductor chip) 1 with high heat generation is mounted on a package substrate 3 or the like, such as a portable device or a thin device.

Further, according to the semiconductor device and the method of manufacturing the same according to the present embodiment, a semiconductor device capable of efficiently diffusing heat can be easily manufactured by using a simple manufacturing process even when there is no space for mounting the radiation fins. And can be manufactured with a high manufacturing yield.

(Embodiment 2) FIG. 2 is a schematic sectional view showing a semiconductor device according to Embodiment 2 of the present invention.

In the semiconductor device of the present embodiment, gold bumps (metal bumps) on the surface of an LSI chip (semiconductor chip) 1 are used.
2 is electrically connected to the front surface of the package substrate 3, the solder bumps 4 on the back surface of the package substrate 3 are electrically connected to the mounting substrate 5, and the housing 10 is disposed on the LSI chip 1. The heat sink 6 is in contact with the back surface of the LSI chip 1 via a heat conductive medium 7, and a part of the heat sink 6 is fixed to the mounting substrate 5. (A contact portion 6c of the radiator 6) is in contact with the housing 10. In this case, the contact portion 6c of the radiator 6 has a bent shape,
Even if the applied force is small, it can be brought into contact with the housing 10.

Therefore, in the semiconductor device of the present embodiment, a part of the heat radiator 6 is not fixed to the mounting substrate 5 but the heat radiator 6
A part of the heat radiator 6 other than that area is attached to the mounting board 5 similarly to the semiconductor device of the first embodiment described above. is there.

According to the semiconductor device of this embodiment, LS
The heat generated in the I chip (semiconductor chip) 1 is transmitted to the heat radiator 6 via the heat conductive medium 7 and transferred to the mounting board 5 and the housing 10 in a low temperature state, so that the LS
The heat generated from the I chip 1 can be removed from the LSI chip 1 in an excellent state.

Therefore, according to the semiconductor device of the present embodiment, even when there is not enough space to attach the heat radiation fins, the heat generated from the LSI chip 1 can be efficiently used by using the heat radiator 6 having a small area. The high-heat-generating LSI chip 1 can be mounted on the package substrate 3 or the like.

According to the semiconductor device of the present embodiment, the same effects as in the first embodiment can be obtained.

(Embodiment 3) FIG. 3 is a schematic sectional view showing a semiconductor device according to Embodiment 3 of the present invention.

In the semiconductor device of the present embodiment, a gold bump (metal bump) on the surface of an LSI chip (semiconductor chip) 1 is used.
2 is electrically connected to the front surface of the package substrate 3, the solder bumps 4 on the back surface of the package substrate 3 are electrically connected to the mounting substrate 5, and the housing 10 is disposed on the LSI chip 1. The heat sink 6 is in contact with the back surface of the LSI chip 1 via a heat conductive medium 7, and a part of the heat sink 6 is fixed to the housing 10. Are in contact with the housing 10.

In the method of manufacturing a semiconductor device according to the present embodiment, after the gold bumps 2 on the surface of the LSI chip 1 are electrically connected to the surface of the package substrate 3,
Electrically connecting the solder bumps 4 on the back surface of the substrate to the mounting substrate 5, fixing a part of the radiator 6 to the housing 10 and bringing a part of the radiator 6 into contact with the housing 10,
After providing the heat conductive medium 7 on the back surface of the chip 1, the housing 10
The heat radiator 6 attached to the LSI chip 1 is placed on the back surface of the LSI chip 1 and the heat radiator 6 is brought into contact with the back surface of the LSI chip 1 via the heat conductive medium 7.

Therefore, in the semiconductor device of the present embodiment, the mounting portion 6a of the radiator 6 is fixed to the housing 10, and the other end of the radiator 6 (the contact portion 6c of the radiator 6) is connected to the housing. It is in contact with the body 10.

With respect to the arrangement of the heat radiator 6, after the heat radiator 6 is fixed (attached) to the housing 10, for example, a heat conductive sheet (for example, a heat conductive sheet (not shown)) is provided on the back surface of the LSI chip 1 mounted on the package substrate 3. After adhering the heat conductive medium 7 made of resin, the heat radiator 6 is mounted on the LSI chip 1 with the heat radiator 6 mounted thereon such that the heat radiator 6 is placed on the LSI chip 1. At this time, the height is adjusted so that a part of the heat radiator 6 is in contact with the heat conduction medium 7. When fixing the radiator 6 to the housing 10, an adhesive 8 such as solder is used.
The heat radiator 6 is attached to the housing 10 by using. Further, the contact portion 6c of the heat radiator 6 can be brought into contact with the housing 10 by having a bent shape.

Therefore, even if the height of the back surface of the LSI chip 1 varies, one end of the heat radiator 6 can slide, so that the mounting height of the heat radiator 6 changes and stable contact can be maintained. .

According to the semiconductor device of the present embodiment, the same effects as those of the first and second embodiments can be obtained.

Although the invention made by the inventor has been specifically described based on the embodiments of the present invention, the present invention is not limited to the above embodiments, and various modifications may be made without departing from the gist of the invention. Needless to say, it can be changed.

For example, in the semiconductor device and the method of manufacturing the same according to the present invention, various semiconductor integrated circuit device chips other than the LSI chip can be applied as the semiconductor chip, and MOSFET, C
MOSFETs or bipolar transistors or semiconductor elements combining them can be used.
The present invention can be applied to an S-type, CMOS-type, BiMOS-type or BiCMOS-type semiconductor integrated circuit device and a method of manufacturing the same.

[0055]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1). According to the semiconductor device of the present invention, the heat radiator is in contact with the back surface of the LSI chip via the heat conductive medium, and a part of the heat radiator is fixed to the mounting board, so that the LSI chip (the semiconductor The heat generated in the chip is transferred to the heat radiator via the heat conductive medium, and transferred to the low-temperature mounting board, thereby removing the heat generated from the LSI chip from the LSI chip in an excellent state. be able to.

According to the semiconductor device of the present invention, the heat radiator is in contact with the back surface of the LSI chip 1 via the heat conductive medium, and a part of the heat radiator is fixed to the mounting board. As a result, the mounting substrate has a larger surface area than the LSI chip or the package substrate and can transmit heat to the air in an extremely small resistance state, so that heat generated from the LSI chip can be removed from the LSI chip in an excellent state. .

Further, according to the semiconductor device of the present invention, since the heat radiator is electrically connected to the ground conductive layer on the mounting board, the ground conductive layer on the mounting board has a high wiring density and a high conductive property. Because it is a layer
Diffusion of heat in the mounting board is performed efficiently,
The heat generated from the chip can be effectively removed from the LSI chip.

Therefore, according to the semiconductor device of the present invention, an LSI chip (semiconductor chip) with high heat generation can be mounted on a package substrate or the like.

According to the semiconductor device of the present invention, since the heat radiator is electrically connected to the ground conductive layer of the mounting substrate, the heat radiator completely covers the LSI chip and the package substrate. However, since a shielding effect of electromagnetic waves can be obtained, a mounting structure with little influence on EMI (electromagnetic interference) can be obtained.

(2). The semiconductor device of the present invention can be applied to various semiconductor devices such as a semiconductor integrated circuit device having a flip-chip type BGA or CSP package structure. Therefore, the semiconductor device of the present invention can sufficiently dissipate heat even when sufficient space cannot be secured above the package mounting portion of the mounting board or when heat dissipating fins cannot be used, such as in portable devices and thin devices. Can be performed at high temperatures, such as mobile devices and thin devices.
The present invention can be applied to a device in which an SI chip (semiconductor chip) is mounted on a package substrate or the like.

(3). According to the semiconductor device and the method of manufacturing the same of the present invention, a semiconductor device capable of efficiently diffusing heat is manufactured with a high manufacturing yield by using an easy manufacturing process even when there is no space for mounting a radiation fin. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a semiconductor device according to a second embodiment of the present invention;

FIG. 3 is a schematic sectional view showing a semiconductor device according to a third embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LSI chip (semiconductor chip) 2 Gold bump (metal bump) 3 Package board 4 Solder bump 5 Mounting board 5a Ground conductive layer 5b Through hole 5c Conductive layer 6 Heat radiator 6a Heat radiator attachment part 6b Heat radiator chip back contact part 6c Contact portion of heat radiator 7 Heat conduction medium 8 Adhesive 10 Housing

Claims (9)

[Claims] 1. A semiconductor device in which metal bumps on a surface of a semiconductor chip are electrically connected to a surface of a package substrate, and solder bumps on a back surface of the package substrate are electrically connected to a mounting substrate. A semiconductor device, wherein a heat radiator is in contact with the back surface of the semiconductor chip via a heat conductive medium, and a part of the heat radiator is fixed to the mounting substrate. A metal bump on a surface of the semiconductor chip is electrically connected to a surface of the package substrate; a solder bump on a back surface of the package substrate is electrically connected to a mounting substrate; A semiconductor device in which a housing is disposed, wherein a heat radiator is in contact with a back surface of the semiconductor chip via a heat conductive medium, and a part of the heat radiator is fixed to the mounting substrate. And a part of the heat radiator is in contact with the housing. 3. The semiconductor device according to claim 1, wherein a ground conductive layer and the radiator in the mounting board are arranged in a region where a part of the radiator is fixed to the mounting board. A semiconductor device which is electrically connected. A metal bump on a surface of the semiconductor chip is electrically connected to a surface of the package substrate; a solder bump on a back surface of the package substrate is electrically connected to a mounting substrate; A semiconductor device in which a housing is disposed, wherein a radiator is in contact with a back surface of the semiconductor chip via a heat conductive medium, and a part of the radiator is fixed to the housing. And a part of the heat radiator is in contact with the housing. 5. The semiconductor device according to claim 1, wherein a material of the radiator is copper, aluminum, a copper alloy, or an aluminum alloy. 6. The semiconductor device according to claim 1, wherein the heat radiator in a region attached to the mounting board or the housing or a region contacting the housing is bent. A semiconductor device, wherein the heat radiator in a region that is in contact with the back surface of the semiconductor chip has a flat shape. 7. The semiconductor device according to claim 1, wherein a material of the heat conductive medium is a resin such as grease or a heat conductive sheet. 8. A step of electrically connecting the metal bumps on the surface of the semiconductor chip to the surface of the package substrate, and then electrically connecting the solder bumps on the back surface of the package substrate to the mounting substrate. After the heat conductive medium is provided, the heat radiator is placed on the back surface of the semiconductor chip, and the heat radiator is brought into contact with the back surface of the semiconductor chip via the heat conductive medium, and the heat radiator is mounted on the mounting board. Fixing the semiconductor device to the semiconductor device. 9. A step of electrically connecting the metal bumps on the surface of the semiconductor chip to the surface of the package substrate, and then electrically connecting the solder bumps on the back surface of the package substrate to the mounting substrate. Fixing the heat sink to the housing and contacting a part of the heat radiator with the housing; providing a heat conductive medium on the back surface of the semiconductor chip; and then connecting the heat radiator attached to the housing to the semiconductor chip. Contacting the heat radiator with the back surface of the semiconductor chip via the heat conductive medium while being placed on the back surface of the chip.