JPH104163A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which improves heat dissipation of a high-speed high-frequency semiconductor package and a three dimensional semiconductor package and is applicable under the equipment conditions wherein the wind speed in forced air cooling is limited. SOLUTION: On a high density mounting board 1, a high-speed high-frequency semiconductor package 2 and a plurality of three dimensional semiconductor packages 3 are mounted. The semiconductor packages 2 and 3 on the high density mounting board 1 are covered with an air duct 4, the local flow speed near the three dimensional semiconductor package 3 mounted under the wind is increased, and heat transmission is efficiently promoted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device in which a high-speed high-frequency semiconductor chip and a plurality of memory semiconductor chips are three-dimensionally mounted at high density.

[0002]

2. Description of the Related Art FIG. 5 is a perspective view for explaining a conventional semiconductor device, FIG. 6A is an enlarged front view of a portion A in FIG.
FIG. 6B is an enlarged side view of a portion A in FIG. 5.

In FIG. 1, a high-speed and high-frequency semiconductor package 2 is mounted at the center of a high-density mounting substrate 1 because of its electrical characteristics. The semiconductor package 2 has a structure in which a semiconductor chip for high-speed and high-frequency waves and a carrier substrate are bonded by metal bumps, and radiation fins are bonded to the back surface of the semiconductor chip via an adhesive.

[0004] A plurality of three-dimensional semiconductor packages 3 are mounted around the substrate 1. The three-dimensional semiconductor package 3 has a structure in which a semiconductor package in which a memory semiconductor chip 21 is bonded to a carrier substrate 20 by metal bumps 22a and a semiconductor package having the same configuration as the semiconductor package is bonded in three dimensions by metal bumps 22b. It was.

[0005]

In the above-mentioned conventional semiconductor device, in an environment where the wind speed of forced convection cooling is restricted, the heat generated from the semiconductor chip is poorly dissipated, and the chip junction temperature during operation is allowed. There was a problem that it was more than the value.

The first reason is that a three-dimensional semiconductor package block row mounted particularly after a high-speed high-frequency semiconductor package is leeward during forced convection cooling, and is thus affected by heat radiation from the windward block row. This is because the chip junction temperature becomes maximum.

The second reason is that the heat dissipation is rapidly reduced by the multi-stage connection of the three-dimensional semiconductor package, and the temperature of the chip junction sandwiched between the upper and lower parts is particularly maximized.

An object of the present invention is to provide a semiconductor device having excellent heat radiation performance applicable to personal equipment such as a personal computer in which the wind speed at the time of forced convection cooling is restricted to about 0.5 m / s due to downsizing of equipment and noise. It is in.

[0009]

In order to achieve the above object, a semiconductor device according to the present invention has a wind tunnel, and has a plurality of three-dimensional semiconductor packages mounted around a high-speed and high-frequency semiconductor package. The wind tunnel covers the high-speed and high-frequency semiconductor package and the three-dimensional semiconductor package, and forcibly introduces a cooling fluid into both packages.

In the wind tunnel, the flow passage area on the cooling fluid outlet side is smaller than that on the cooling fluid inlet side.

Further, the wind tunnel is detachable from each package.

Further, the three-dimensional semiconductor package is formed by stacking a semiconductor package in which a carrier substrate and a semiconductor chip are joined by metal bumps and a semiconductor package having the same configuration as the semiconductor package by joining with metal bumps. A radiation fin joined by an adhesive to a ground potential conductor pattern formed on the back surface of the uppermost carrier substrate of the three-dimensional semiconductor package, wherein the ground potential conductor pattern comprises a ground between the carrier substrate and the semiconductor chip. Only the potential is selected and thermally and electrically coupled.

The heat radiation fins have at least two kinds of radiation fins so as to have the same wind direction as the forced convection cooling fluid.

Further, a gap is provided on the back surface of each of the plurality of semiconductor chips constituting the three-dimensional semiconductor package, and a heat sink is provided in the gap.

Further, a gap is provided on the back surface of each of the plurality of semiconductor chips constituting the three-dimensional semiconductor package, and a heat radiating plate is provided in the gap. It has been joined.

Further, a gap is provided on the back surface of each of the plurality of semiconductor chips constituting the three-dimensional semiconductor package, and a heat sink is provided in the gap, and a tip of the heat sink projects into the surrounding cooling fluid. is there.

[0017]

The heat generated by the semiconductor chip mounted on the semiconductor device is provided with an inclined wind tunnel that covers the entire high-density mounting substrate, so that the heat transfer particularly to the three-dimensional semiconductor package block row mounted leeward is promoted. .

The three-dimensional semiconductor package further comprises:
By providing a heat-dissipating path of the ground potential from the semiconductor chip and the carrier substrate to the heat-dissipating fins and a heat-dissipating path from the back of the semiconductor chip to the heatsink, heat can be efficiently dissipated in the surrounding cooling fluid.

According to the present invention, it is possible to provide a semiconductor device in which the chip junction temperature during operation is not more than an allowable value even in a personal device environment such as a personal computer in which the wind speed during forced convection cooling is restricted.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIGS. 1 and 2 are configuration diagrams showing Embodiment 1 of the present invention.

In terms of electrical characteristics, the propagation time between semiconductor chips mounted on a mounting board plays a large role in high-speed operation. Therefore, as shown in FIG.
The three-dimensional semiconductor package 3 is arranged around the high-speed and high-frequency semiconductor package 2 as a center, and the three-dimensional semiconductor package 3 is mounted as close as possible to the high-speed and high-frequency semiconductor package 2 with high density. In this case, since the heat generation density per unit area rises sharply, optimal heat dissipation measures are required.

Therefore, according to the present invention, the semiconductor package 2 for high-speed and high-frequency operation, which consumes the most power, is mounted on the center of the mounting substrate 1 by directly bonding the radiation fins to the back surface of the semiconductor chip via an adhesive having high thermal conductivity. I do. The three-dimensional semiconductor package 3 in which memory semiconductor chips are three-dimensionally stacked is provided with heat-radiating fins and a heat-radiating plate having high thermal conductivity as heat-conducting paths. As close as possible, a plurality of three-dimensional semiconductor packages 3 are mounted. The details of the structure of the three-dimensional semiconductor package 3 are described in the second embodiment.
Will be described.

Further, in the present invention, as shown in FIGS. 1 and 2, the inclined wind tunnel 4 or 5 covering the entire high-density mounting substrate 1 is provided.
Is a high-density mounting substrate 1 with an L-shaped groove 10 and a U-shaped groove 11.
It is stuck to.

The inclined wind tunnels 4 and 5 are composed of side walls 4c and 5c rising upward from the substrate 1 and roofs 4d and 5d provided between the side walls 4c and 5c.
Is inclined such that the cooling fluid inlet side 4a is higher and the cooling fluid outlet side 4b is lower.

The inclined wind tunnel 5 shown in FIG.
d is not a flat surface but is formed by bending it into three surfaces.

Therefore, the inclined wind tunnels 4 and 5 cover the side surfaces of the semiconductor package 3 on the substrate 1 with the upright side walls 4c and 5c, and cover the upper portions of the semiconductor packages 2 and 3 with the roof portions 4d and 5d.

According to the embodiment of the present invention, the total power consumption of the chips of the semiconductor packages 2 and 3 mounted on the high-density mounting substrate 1 is equivalent to 20 W (0.5 W / cm ² per unit area). ), And forced convection cooling is adopted as the cooling method.

In recent years, the wind speed is limited to 1 m / s or less at most due to noise problems in personal devices such as personal computers and restrictions due to downsizing of the housing.

Therefore, a precondition is a heat radiation structure in which the junction temperature of the semiconductor chip during operation at a wind speed of 0.5 m / s and an environmental temperature of 40 ° C. in the housing is below an allowable value. For example, as shown in FIG. 5, 20 W is supplied to a conventional semiconductor device which does not include the inclined wind tunnels 4 and 5 and further does not include the heat radiation fins or the heat radiation plate in the three-dimensional semiconductor package 3 and has a wind speed of 0.5 m / s, when the environmental temperature in the housing was 40 ° C., the junction temperatures of all the mounted semiconductor chips were higher than the allowable value. In particular, the calorific value of the block row of the three-dimensional semiconductor package 3 mounted leeward with respect to the wind direction became the maximum.

That is, in the conventional structure shown in FIG. 5, heat generated in the three-dimensional semiconductor package 3 and the high-speed high-frequency semiconductor package 2 arranged on the upstream side is generated with respect to the three-dimensional semiconductor package 3 arranged on the leeward side. Since it diffuses into the cooling fluid and raises the air temperature and includes the flow resistance,
The local flow velocity is several steps smaller. Furthermore, a stagnation region is formed between three-dimensional semiconductor packages adjacent to each other in the flow direction, and the effective heat transfer area is reduced.

Therefore, according to the present invention, as shown in FIGS. 1 and 2, the roof portion 4 extends from the inlet side 4a, 5a to the outlet side 4b, 5b of the forced convection cooling fluid covering the entire high-density mounting board 1.
By providing the wind tunnel 4 or the wind tunnel 5 in which d and 5d are inclined, the above-mentioned conventional problem is solved.

According to the first embodiment, the structure having the inclined wind tunnel 4 shown in FIG. 1 has a casing structure in which the wind speed of the forced convection cooling fluid on the cooling fluid inlet side 4a is 1.0 m / s. The semiconductor packages 2 and 3 of the substrate 1 are formed by the wind tunnel 4.
When the cooling fluid is forcibly sprayed onto the semiconductor packages 2 and 3 through the wind tunnel 4 and the environment temperature of 40 ° C. and the power of 20 W are supplied, the junction temperature becomes lower than the allowable temperature.

Further, in the configuration having the inclined wind tunnel 5 shown in FIG. 2, the casing structure is such that the forced convection cooling fluid at the inlet side 5a of the cooling fluid has a wind velocity of 0.5 m / s. Similarly, when an environment temperature of 40 ° C. and a power of 20 W were supplied, the junction temperature was shown to be below the allowable value.

As described above, based on the physical principle that the flow rate flowing into the container and the flow rate flowing out are constant, first, the roof portions 4d and 5d are provided at the cooling fluid outlet sides 4b and 5b with inclination. Accordingly, the vicinity of the block of the leeward semiconductor package 3 (the cooling fluid outlet side 4a, 5
The local flow velocity b) is several times faster than the inlet side 4a, 5a, and the flow area of the cooling fluid outlet side 4b, 5b is formed by the substrate 1, the side walls 4c, 5c, and the roof parts 4d, 5d. This tendency becomes more remarkable as the opening area of the flow path is made as small as possible.

Second, when the cooling fluid collides with the inner surfaces of the inclined roof portions 4d and 5d of the wind tunnels 4 and 5, the cooling fluid is disturbed in the vector direction, particularly in the downstream block region having a large inclination angle. Flow effect.

Therefore, it is possible to reduce the thermal resistance by several stages as compared with a conventional semiconductor device having no inclined wind tunnel. The materials forming the inclined wind tunnels 4 and 5 are not particularly limited.
A lightweight and low-cost thin aluminum plate may be used.

Next, the L-shaped groove 10 and the U-shaped groove 11 shown in FIG. 1 will be described. For example, providing a wind tunnel in natural convection cooling has an adverse effect.
The U-shaped groove 10 and the U-shaped groove 11 are opened and removed in the horizontal direction and used. In the case of fixing, the L-shaped groove 11 and the side surface of the substrate 1 may be screwed and used.

(Embodiment 2) FIGS. 3A and 4A
FIG. 3 is an enlarged front view of a three-dimensional semiconductor package according to a second embodiment of the present invention, and FIGS. 3B and 4B are side views of the same.

The three-dimensional semiconductor package 3, which is effective as a means for increasing the memory capacity, includes a semiconductor package in which connection pads of a carrier substrate 20 and electrode pads of a memory semiconductor chip 21 are joined by metal bumps 22a, and has the same configuration as the semiconductor package. Bumps between two semiconductor packages
It is configured by being joined three-dimensionally and stacked three-dimensionally.
For example, if the power consumption per memory semiconductor chip 21 in the three-stage stacked configuration shown in the figure is 1 W, the heat generation density per unit area simply triples.

Using the conventional three-dimensional three-dimensional semiconductor package shown in FIG. 5, the power is 3 W, the wind speed is 0.5 m / s,
It has been shown that when the ambient temperature is 40 ° C., the junction temperature of the semiconductor chip far exceeds the allowable value. In particular, the temperature of the middle memory semiconductor chip 21 sandwiched between the upper and lower sides becomes the maximum.

Therefore, according to the configuration of the three-dimensional semiconductor package 3 of the present invention shown in FIG. 3, the ground potential conductor pattern 23 is formed on the back surface of the carrier substrate 20, and the uppermost carrier substrate 20 and the ground potential conductor pattern 23 Is provided with a radiation fin 24 joined through an adhesive.

In this configuration, the ground potential conductor pattern 23 for mounting the radiating fins on the rear surface of the carrier substrate 20 selects only the ground potential of each of the carrier substrates 20 and the semiconductor chips 21 connected in multiple stages, and electrically and thermally. Since they are connected, they become heat conduction paths generated from the semiconductor chip.

Accordingly, heat can be efficiently dissipated from the heat conduction path into the cooling fluid through the radiation fins 24. Next, most of the memory semiconductor chips 2
The length of one side is rectangular at a ratio of approximately 3: 1. The mounting direction of the three-dimensional semiconductor package 3 formed by connecting these in multiple stages has at least two directions, thereby enabling high-density mounting. The ground potential conductor pattern 23 and the radiating fins 24 are connected to each other by using a conductive adhesive to have the same potential as the ground. Performance improves.

Therefore, as shown in FIG. 3, the fins of the radiation fins 24 have two directions depending on the mounting position of the three-dimensional semiconductor package 3. That is, the fin direction 21a of the radiation fin 24 is used in a case where one long side of the three-dimensional semiconductor package 3 is mounted on the wind direction side of the cooling fluid, and the fin direction 24b of the radiation fin 24 is one side of the three-dimensional semiconductor package 3. By using the case where the short surface side is mounted on the wind direction side of the cooling fluid, heat generated from the semiconductor chip has two directions through the heat conduction path selected only for the ground potential of the carrier substrate 20 or the semiconductor chip 21 described above. These radiation fins 24a, 24b
Thereby, heat can be efficiently diffused into the cooling fluid.

Next, according to the present embodiment using the three-stage connection structure shown in FIG. 3, in the above-described configuration having only the heat conduction path in which the ground potential connected to the radiation fin 24 is selected, the junction of the chip during operation is The temperature could not be reduced below the permissible value. In particular, the memory semiconductor chip 2
The temperature of the chip in the middle sandwiched above and below 0 reached the maximum temperature.

Therefore, when the heat generated from the element surface of each memory semiconductor chip 20 reaches the back surface of the chip, the height of the metal bump 22b is reduced between the back surface of the memory semiconductor chip 21 and the back surface of the carrier substrate 20 as shown in FIG. A gap is provided by control, and a heat sink 25a is provided in the gap. The heat radiating plate 25a is about 0.1 mm and is not particularly limited to a material, but may be Cu or Mo composite material having a high thermal expansion coefficient close to that of high thermal conductivity Cu or silicon.
Note that the joining portion does not have to be joined with an adhesive that becomes a heat resistor.

In this configuration, since the heat radiating plate 25 is provided directly on the back surface of the memory semiconductor chip 21, a new heat conduction path for dissipating the cooling air from the back surface of the memory semiconductor chip 21 is provided. Furthermore, as shown in FIG. 3, in the case where one long side of the three-dimensional semiconductor package 3 is mounted on the wind direction side of the cooling fluid,
5 is joined to the side wall of the radiating fin 24 with an adhesive having high thermal conductivity.

On the other hand, as shown in FIG. 4, in the case where the short side of one side of the three-dimensional semiconductor package 3 is mounted on the wind direction side of the cooling fluid, joining the heat radiating plate 25 to the side wall of the heat radiating plate 24 requires cooling. Since the fluid is hindered, effective heat transfer is promoted by protruding the distal end 25b of the radiator plate 25 into the surrounding cooling air as much as possible as shown in FIG.

That is, the heat generated from each of the multi-staged semiconductor chips is generated by selecting the ground potential of the memory semiconductor chip and the carrier substrate and leading to the heat radiation fins and the back surface of each semiconductor chip. And a second heat radiation path leading to the heat radiating plate, and furthermore, by joining the tip of the heat radiating plate to a heat radiating fin, the first and second heat radiating paths become a common heat radiating path. Improves the heat dissipation of

[0051]

As described above, according to the present invention, even when the wind speed of forced convection cooling is 0.5 m / s to 1.0 m / s, the chip junction temperature becomes lower than the allowable value, and therefore The present semiconductor device can be applied under the environmental conditions of a personal device such as a personal computer in which the wind speed at the time of forced convection cooling is restricted due to such a problem.

The first reason is that the heat generated from each of the memory semiconductor chips constituting the three-dimensional semiconductor package is transferred to a radiating fin using a ground potential as a first radiating path and to a radiating fin using a ground potential as a heat flow path. Efficient heat dissipation by providing a heat dissipation path from the tip of the heat sink joined to the backside of the semiconductor chip to the heat dissipation fins and a heat dissipation path from the protrusion of the tip of the heat sink to the surrounding cooling fluid. This is because

The second reason is that by providing an inclined wind tunnel covering the entire high-density mounting substrate on which a plurality of semiconductor packages are mounted, the local flow velocity of the semiconductor package block region mounted leeward is more than the inlet flow velocity. This is because heat transfer is promoted efficiently by several steps, and the effect increases as the flow passage area of the inclined wind tunnel outlet is made as small as possible.

Further, the thermal resistance can be reduced by the turbulence effect of the cooling fluid in the downstream block region where the inclination angle of the wind tunnel is increased.

As described above, according to the present invention, the wind speed of the forced convection cooling fluid is 0.5 m /
It was shown that the chip junction temperature was lower than the allowable temperature even under the condition of s and the environmental temperature was 40 ° C.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a semiconductor device according to the first embodiment of the present invention.

FIG. 3A is a front view showing a semiconductor device according to a second embodiment of the present invention, and FIG. 3B is a side view thereof.

FIG. 4A is a front view showing a semiconductor device according to a second embodiment of the present invention, and FIG. 4B is a side view thereof.

FIG. 5 is a perspective view showing a conventional semiconductor device.

FIG. 6A is a front view showing a conventional example, and FIG. 6B is a side view thereof.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 high-density mounting substrate 2 high-speed high-frequency semiconductor package 3 three-dimensional semiconductor package 4 inclined wind tunnel 4 a cooling fluid inlet side 4 b cooling fluid outlet side 5 inclined wind tunnel 5 a cooling fluid inlet side 5 b cooling fluid outlet side 10 L-shaped groove 11 U-shaped groove 20 Carrier substrate 21 Memory semiconductor chip 22a Metal bump 22b Metal bump 23 Ground potential conductor pattern 24 Radiation fin 24a Radiation fin direction 24b Radiation fin direction 25 Radiator plate 25a Radiator plate tip 25b Radiator plate tip

Claims (8)

[Claims] 1. A semiconductor device having a wind tunnel and a plurality of three-dimensional semiconductor packages mounted around a high-speed and high-frequency semiconductor package, wherein the wind tunnel covers the high-speed and high-frequency semiconductor package and the three-dimensional semiconductor package. A semiconductor device wherein a cooling fluid is forcibly introduced into both packages. 2. The semiconductor device according to claim 1, wherein the flow channel area of the wind tunnel on the cooling fluid outlet side is smaller than that on the cooling fluid inlet side. 3. The semiconductor device according to claim 1, wherein the wind tunnel is detachable from each package. 4. The three-dimensional semiconductor package is formed by three-dimensionally stacking a semiconductor package in which a carrier substrate and a semiconductor chip are joined by metal bumps and a semiconductor package having the same configuration as the semiconductor package by joining with metal bumps. A radiation fin joined by an adhesive onto a ground potential conductor pattern formed on the back surface of the uppermost carrier substrate of the three-dimensional semiconductor package, wherein the ground potential conductor pattern is formed of a carrier substrate and a semiconductor chip. 2. The semiconductor device according to claim 1, wherein only the ground potential is selected and thermally and electrically coupled. 5. The semiconductor device according to claim 4, wherein said radiating fins have at least two types so as to have the same wind direction as the forced convection cooling fluid. 6. The semiconductor according to claim 1, wherein a gap is provided on the back surface of each of the plurality of semiconductor chips constituting the three-dimensional semiconductor package, and a heatsink is provided in the gap. apparatus. 7. A gap is provided on the back surface of each of the plurality of semiconductor chips constituting the three-dimensional semiconductor package, a heat sink is provided in the gap, and a tip of the heat sink is attached to a side wall of the heat radiation fin by an adhesive. 7. The semiconductor device according to claim 6, wherein the semiconductor device is joined by: 8. A plurality of semiconductor chips constituting the three-dimensional semiconductor package, wherein a gap is provided on the back surface of each of the semiconductor chips, and a heat sink is provided in the gap, and a tip of the heat sink projects into the surrounding cooling fluid. The semiconductor device according to claim 7, wherein