JPH0555418A - Semiconductor integrated circuit device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To improve the heat dissipation efficiency of a semiconductor chip in a flip-chip connection type semiconductor integrated circuit device. This semiconductor integrated circuit device is a semiconductor integrated circuit device in which a semiconductor chip 1 is mounted on a wiring board 7, and the semiconductor chip 1 is formed on the surface of an active region 4 of the semiconductor chip 1.
The heat radiation bumps 2b independent of the circuit of FIG. 2 are provided, and the heat radiation pads 12 are provided on the wiring board 7 in correspondence with the heat radiation bumps 2b.
While forming b, the heat dissipation bumps 2b are brought into contact with the heat dissipation pads 12b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip-chip connection type semiconductor integrated circuit device.

[0002]

2. Description of the Related Art Conventionally, various connection methods have been adopted for a semiconductor integrated circuit device in which a semiconductor chip is mounted on a wiring board. Generally, a connection method such as wire bonding or TAB (Tape Automated Bonding) is used.

By the way, these connection methods take a form in which a pad for connection is formed around the semiconductor chip arrangement portion on the wiring board and the pad and the pad provided on the semiconductor chip are connected by a lead. However, there is a limit in using the board space.

Therefore, in recent years, attention has been paid to a flip chip connection method in which bumps are provided on a semiconductor chip and the semiconductor chip is mounted on a wiring board in an inverted state. In this connection method, since the pads can be provided in the substrate space inside the semiconductor chip placement portion, the semiconductor chips can be mounted at high density. Also, with this connection method, since the bumps provided on the semiconductor chip can be formed with a small diameter of 100 μm or less, it is possible to increase the number of input / output terminals of the semiconductor chip by narrowing the pitch between the pads on the wiring board.

A conventional flip-chip connection type semiconductor integrated circuit device will now be described with reference to FIGS. 6 (a) and 6 (b).

FIG. 6A is a plan view showing bumps of a semiconductor chip.

In the figure, reference numeral 61 is a semiconductor chip. The semiconductor chip 6 is formed on one surface of the semiconductor chip 61.
A large number of input / output terminals are formed as bumps 62 around the edge portion of 1. The bump 62 is connected to a circuit (not shown) inside the semiconductor chip 61.

FIG. 6B is a sectional view showing a state in which the semiconductor chip 61 is mounted on the wiring board 63. As shown in the figure, the wiring board 63 is a wiring board 6 having high thermal conductivity.
4 and a thin film wiring layer 65 formed on the wiring board 64,
The pad 66 is provided on the thin film wiring layer 65.
A wiring conductor 67 is formed in the inner layer of the thin film wiring layer 65, and one end of this wiring conductor 67 is drawn to the upper portion of the thin film wiring layer 65 and connected to the pad 66. Then, the bumps 62 of the semiconductor chip 61 are brought into contact with the pads 66 of the wiring board 63 to form a semiconductor integrated circuit device.

In this semiconductor integrated circuit device, the heat of the semiconductor chip 61 is transferred to the wiring board 63 via the bumps 62 formed on the semiconductor chip 61. For example, the heat generated in the semiconductor chip 61 is transferred to the wiring board 63 via the circuit connecting bumps 62 formed in the peripheral portion of the semiconductor chip 61.

However, if the heat generated in the semiconductor chip 61 is dissipated in this way, the heat dissipation path is limited, so the heat resistance is high and the heat dissipation efficiency is poor. In addition, for the thin film wiring layer 65 of the wiring board 63, an organic material having poor thermal conductivity, such as polyimide, which gives priority to electrical characteristics, is often used. The thermal resistance of the thin film wiring layer 65 also becomes a factor that hinders heat dissipation.

[0011]

As described above, in the conventional flip-chip connection type semiconductor integrated circuit device described above, the heat generated at the central portion of the semiconductor chip is passed through the bumps around the edge of the semiconductor chip to the wiring substrate. Therefore, the heat resistance is high and the heat dissipation efficiency is poor.

The present invention has been made to solve the above problems, and provides a semiconductor integrated circuit device capable of efficiently radiating the heat generated by a semiconductor chip mounted by a flip chip connection method to a wiring board. It is intended to be provided.

[0013]

In order to achieve the above-mentioned object, the semiconductor integrated circuit device of the present invention has a semiconductor chip having bumps mounted on a wiring board having pads formed corresponding to the bumps. In a semiconductor integrated circuit device, a heat-releasing bump independent of an electric signal circuit is provided on the active region surface of the central part of the semiconductor chip, and pads are formed on the wiring board so as to correspond to the heat-releasing bumps and are brought into contact with each other. It becomes.

The wiring board is formed by using a material having high thermal conductivity, and a wiring layer is formed on this wiring board. At this time, a filled via is formed in the wiring layer corresponding to the bump, or an inorganic material is used for the insulating layer.

[0015]

According to the present invention, the heat radiation bumps independent of the semiconductor chip circuit are provided on the active area surface of the semiconductor chip, and pads are formed on the wiring board so as to correspond to the heat radiation bumps and contact the heat radiation bumps. I am letting you.

Therefore, the heat generated in the semiconductor chip is transferred to the wiring board in the shortest distance, and the transfer of heat in the wiring board is improved by using the heat conductive substrate material. Further, the thermal resistance in the wiring layer portion is also reduced.

As a result, the heat dissipation efficiency of the semiconductor chip can be improved.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a plan view showing a semiconductor chip used in the semiconductor integrated circuit device of the present invention.

In the figure, 1 is a semiconductor chip.
On one surface of the semiconductor chip 1, bumps 2a for electrical input / output terminals are arranged along the peripheral portion thereof. Further, the heat dissipation bumps 2b are arranged in a two-dimensional array on the active region at the center of the semiconductor chip 1. These bumps 2a and 2b are formed by Pb / Sn-based solder plating.

Next, the structure of the semiconductor chip 1 will be described in detail with reference to FIG.

FIG. 2 is a sectional view taken along the line AA of FIG.

As shown in the figure, a passivation film 3 is formed on the surface of the semiconductor chip 1. Inside the passivation film 3, on the active region 4 of the semiconductor chip 1, a wiring layer 5 to which a power supply system or a signal system circuit is connected is formed. Further, on the passivation film 3, bumps 2a for electrical input / output terminals connected to the wiring layer 5 are formed. Further, on the passivation film 3, a heat radiation bump 2b is formed independently of the bump 2a via a pad 6 made of a Cu conductor.

Next, an embodiment of the semiconductor integrated circuit device of the present invention will be described with reference to FIG.

FIG. 3 is a sectional view showing a state in which the semiconductor chip 1 is mounted on a wiring board by a flip chip connection method.

In the figure, 7 is a wiring board. The wiring board 7 includes silicon (thermal conductivity: K, K = 150 W / m ° C.), AlN (K = 170 W / m) as a material having good thermal conductivity.
C.) or SiC (K = 270 W / m.degree. C.) or the like is used. A thin film wiring layer 8 is formed on the upper surface of the wiring board 7. The thin film wiring layer 8 is composed of an insulating layer 10 formed of a material such as polyimide that has good electrical characteristics (low dielectric constant), and a wiring conductor 11 formed in the insulating layer 10. .. The wiring conductor 11 is mainly composed of copper or aluminum and is deposited by a metal vapor deposition method or a sputtering method, and is formed as a fine wiring by photolithography. The thermal conductivity K of the polyimide used for the insulating layer of the thin film wiring layer 8 is 0.2 W / m ° C.,
Silicon (K = 150W / m ° C) and SiO ₂ (K = 1.4W / m ° C)
In comparison with, the thermal conductivity is poor, that is, two digits for silicon and one digit for SiO ₂ .

Further, on the surface of the thin film wiring layer 8, pads 12 corresponding to the bumps 2a and 2b of the semiconductor chip 1 are formed.
a and 12b are formed. Of these, the pad 12a
Is a circuit connection pad and is connected to the wiring conductor 11. The pad 12b is a heat dissipation pad. Further, a via 13 is formed in the inner layer of the thin film wiring layer 8 to connect the pad 12b to the wiring board 7 vertically. This via 13
In terms of heat dissipation, it is most preferable to vertically stack "filled vias" that fill the via openings with Cu plating or the like. A semiconductor integrated circuit device is configured by mounting the semiconductor chip 1 on the wiring board 7 thus formed by flip-chip connection. In this flip-chip connection, the bumps 2a and 2b of the corresponding semiconductor chip 1 are in contact with the pads 12a and 12b of the wiring board 7, respectively.

Next, the operation of this semiconductor integrated circuit device will be described.

From the circuit of the wiring board 7 of this semiconductor integrated circuit device, power supply / ground potential is supplied to the semiconductor chip 1 via the bumps 2a to input / output signals.

With the operation of the semiconductor chip 1, heat is generated in the semiconductor chip 1. For example, this semiconductor chip 1
The heat generated in the central part of the heat dissipation layer 9 of the wiring board 7 is shortest distance through the via 13 vertically connected to the bump 2b.
And is dissipated in heat.

Here, the change in thermal resistance with respect to the bump area of this embodiment will be described with reference to FIG.

In the figure, in the thin-film wiring layer 8 made of copper / polyimide, the abscissa represents the occupied area ratio of the bumps 2b to the area of the semiconductor chip 1, and the substrate bottom surface from the joint between the semiconductor chip 1 and the bump 2b. The vertical axis is the change in thermal resistance up to. In this embodiment, 250 bumps 2b having a diameter of 100 μm are formed on the surface of the semiconductor chip 1 of 10 mm square.
It is formed in an array of 25 × 25 at μm intervals. In this case, the occupied area of the bump 2b is about 5 mm ² , which is 10 mm.
The occupied area ratio of the bumps 2b to the corner semiconductor chip 1 (area: 100 mm ² ) can be obtained as 5%.

When looking at the thermal resistance when the area ratio of the bumps 2b is as small as 5% in the figure, the thermal resistance is practically reduced to a value close to that when the area ratio is 25% or more. It can be seen that it has been reduced to a level where there is no problem.

As described above, according to the semiconductor integrated circuit device of the present embodiment, since the via 13 is formed in the inner layer of the thin film wiring layer 8 with the conductor such as copper or aluminum, even if the cross-sectional area of the via 13 is small. The via 13 can be used as the shortest heat transfer path, the influence of the thermal resistance of the thin film wiring layer 8 can be minimized, and the efficiency of heat radiation from the semiconductor chip 1 can be improved.

Further, since the heat radiation bumps are provided,
The mechanical connection strength between the semiconductor chip 1 and the wiring board 7 can also be increased.

In this embodiment, the heat radiation bumps of the semiconductor chip are electrically separated from the bumps for the electric input / output terminals, but the ground potential of the power supply system different from the signal system on the wiring board, etc. If so, it may be partially connected.

Next, another embodiment of the semiconductor integrated circuit device of the present invention will be described with reference to FIG. The semiconductor chip 51 of this embodiment has the same structure as that of the above-described embodiments. The flip-chip connection state to the wiring board 52 is also the same as that of the above-mentioned embodiment. As shown in the figure, a thin film wiring layer 53 is formed on the wiring board 51, and the thin film wiring layer 53 is made of an inorganic material such as SiO ₂ or Si ₃ N ₄ . .. In addition, the thin film wiring layer 53
In the inner layer, the wiring conductor 54 is formed including the region where the via is formed in the above embodiment.

In this case, the thermal conductivity of the inorganic material such as SiO ₂ and Si ₃ N ₄ is K = 1.4 W / m ° C., and the heat generated in the semiconductor chip 51 is generated from the bump 55 for heat dissipation in the thin film wiring layer. It is transmitted to the wiring board 51 through 53 itself.

According to this embodiment, by using an inorganic material for the thin film wiring layer, a good heat dissipation effect can be obtained without forming a via because the thermal resistance of the inorganic material is low. Further, since the via does not have to be formed, the thin film wiring layer 53 can be effectively used by forming the wiring conductor 54 on the thin film wiring layer 53 immediately below the semiconductor chip 51, for example.

AlN is formed by plasma CVD or the like.
If the thin film wiring layer is formed using an inorganic material having good thermal conductivity such as (K = 170 W / m ° C.), the thermal resistance of the thin film wiring layer can be further reduced. Furthermore, if AlN is used for both the thin film wiring layer and the wiring substrate, the heat transfer path can be formed of the same material, so that there is no difference in thermal expansion and the reliability of the semiconductor integrated circuit device is improved. be able to.

[0041]

According to the semiconductor integrated circuit device of the present invention,
The heat radiation efficiency from the semiconductor chip to the wiring board can be improved. Also, by providing a heat dissipation bump,
The mechanical connection strength between the semiconductor chip and the wiring board can also be increased.

[Brief description of drawings]

FIG. 1 is a plan view showing a semiconductor chip used in a semiconductor integrated circuit device of the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a sectional view showing an embodiment of a semiconductor integrated circuit device of the present invention.

FIG. 4 is a diagram showing a change in thermal resistance with respect to a bump area in a semiconductor chip.

FIG. 5 is a plan view of another embodiment of the semiconductor integrated circuit device of the present invention.

FIG. 6A is a plan view showing a conventional semiconductor chip. (B) is a sectional view showing a conventional semiconductor integrated circuit device.

[Explanation of symbols]

 1, 51 ………… Semiconductor chip 2a ……………… I / O terminal bumps 2b, 55 ………… Heat dissipation bumps 4 …………………… Active area 7, 52 ………… Wiring board 12a , 12b ... Pads

Claims (1)

[Claims] 1. A semiconductor integrated circuit device in which a semiconductor chip having bumps is mounted on a wiring substrate having pads formed corresponding to the bumps, wherein an electric signal circuit of the semiconductor chip is provided on an active region surface of the semiconductor chip. A semiconductor integrated circuit device, characterized in that it is provided with a heat-releasing bump that is independent of the above.