JP2853700B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device having a heat sink.

[0002]

2. Description of the Related Art Semiconductor devices such as TBGA (Tape)
Figure 4 shows the Ball Grid Array package.
As shown in FIG. 5, the heat radiating plate 1 is made of a high heat conductive metal, for example, a copper material, and is attached to the back surface of the solder bump mounting surface of the TAB tape 3 via the frame type reinforcing plate 2 previously attached. . A liquid high heat conductive adhesive 7 has been used for bonding the semiconductor chip 6 and the heat sink 1. In order to improve the reliability of the heat radiating plate 1, in order to remove moisture such as a cleaning liquid entering the inside of the frame-shaped reinforcing plate 2 during the manufacturing process or mounting of the semiconductor device, it is generated from the resin 5, the adhesive 7, and the like. Opening 8 to allow gas such as steam to escape
Was sometimes provided.

In order to actually bond the semiconductor chip 6 and the heat sink 1, first, as shown in FIG. 4, a liquid high heat conductive adhesive 7 is applied to the semiconductor chip 6 and the heat sink 7.
It is applied to the back surface of the semiconductor chip 6 so that no gap or the like is generated between them. At this time, if the amount of the high thermal conductive adhesive 7 is small, a gap (void) is generated. Therefore, the adhesive is applied thicker than the distance between the semiconductor chip 6 and the high thermal conductive adhesive 7 when they are bonded together.

Next, the heat radiating plate 1 is bonded from the application surface side, and the high thermal conductive adhesive 7 is spread over the entire surface of the semiconductor chip 6. The area in which the high thermal conductive adhesive 7 is spread varies depending on the distance between the semiconductor chip 6 and the heat sink 1.

[0005] The application area of the high thermal conductive adhesive 7 has a great influence on the thermal resistance of the semiconductor device, so that the management of the adhesive area during manufacturing is indispensable. In particular, since it is necessary to control the bonding area of the high thermal conductive adhesive 7 depending on the size of the semiconductor chip 6, the viscosity control of the high thermal conductive adhesive 7 and the accuracy of the application amount are required to be high.

Conventionally, in order to check the state of application of the high thermal conductive adhesive 7, an X-ray inspection apparatus has been used or a semiconductor device has been cut and polished to check the cross-sectional structure thereof. At the time of assembling the semiconductor device, the applied amount of the high thermal conductive adhesive 7 was simply controlled by measuring the applied weight.

[0007]

However, in the prior art shown in FIG. 4, in order to avoid a variation in the thermal resistance value of the product due to a variation in the application area of the high thermal conductive adhesive, a high thermal conductive adhesive is used. There is a problem that it is necessary to apply more than necessary, and the material cost of the high thermal conductive adhesive increases.

More specifically, the bonding area between the semiconductor chip and the radiator plate varies depending on the distance between the semiconductor chip and the radiator plate, as described in the preceding section. Conventionally, since the weight is measured at the time of applying the adhesive and the amount of application is simply controlled, the application area changes depending on the assembly lot, and the thermal resistance value of the product varies.

Here, a description will be given of the results of an experiment conducted to see the effect of the coating amount. For example, chip size 15 × 15m
When the thermal resistance of the heat conductive adhesive was 30%, 50%, and 70% of the chip area, for example, when the wind speed was 1 m, the thermal resistance of the 50% applied area was 30%.
%, And it was confirmed that the thermal resistance of the coated area of 70% was reduced by about 30% as compared with the thermal resistance of 30%. From the above, it can be seen that the thermal resistance value of the product varies due to the variation of the application area.

In the conventional heat sink shape, it is impossible to visually check the spread of the adhesive 7 immediately after bonding, and in order to check the application state, the semiconductor device is cut and polished after the adhesive is cured. By confirming the cross-sectional structure,
Since it is necessary to perform line inspection, it is practically impossible to confirm the spread of the adhesive for each assembly lot. In addition, since the adhesive does not easily spread to the corners on the semiconductor chip, it is necessary to increase the application amount in advance.

It is an object of the present invention to provide a semiconductor device in which the state of application of a highly heat-conductive adhesive can be easily visually checked immediately after attaching a heat sink.

[0012]

To achieve the above object, a semiconductor device according to the present invention is a semiconductor device having a semiconductor chip and a heat sink, wherein the semiconductor chip is bonded to the heat sink by heat conductive bonding. A heat sink that diffuses heat generated in the semiconductor chip, has an opening, and the opening is opened corresponding to the outer periphery of the semiconductor chip; Is to visually confirm the state of application of the high-temperature conductive adhesive near the outer periphery.

[0013]

The semiconductor chip is bonded to the heat sink with a heat conductive adhesive. It is necessary that the heat conductive adhesive is applied to the entire surface of the semiconductor chip in order to conduct the heat of the semiconductor chip to the radiator plate to the maximum.

Therefore, according to the present invention, an opening is provided in the heat sink corresponding to the outer peripheral position of the semiconductor chip bonded to the heat sink, and the application state of the heat conductive adhesive is visually observed through the opening. It is something to check.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1A is a plan view showing Embodiment 1 of the present invention, and FIG.
FIG. 1C is a sectional view taken along the line BB ′ of FIG. 1B.

In FIG. 1, the semiconductor device according to the first embodiment of the present invention comprises a combination of a semiconductor chip 6 and a heat sink 1.

The mounting structure of the semiconductor chip 6 will be specifically described. A cross-shaped frame-shaped reinforcing plate 2 is joined to one surface of the heat radiating plate 1, and a space 2 a that exposes the chip mounting surface 1 a of the heat radiating plate 1 is formed in the center of the frame-shaped reinforcing plate 2. The TAB tape 3 on which the semiconductor chip 6 is mounted is joined to the frame-shaped reinforcing plate 2, and the semiconductor chip 6 is mounted in the space 2 a of the frame-shaped reinforcing plate 2 and is not covered with the sealing resin 5. The back surface is the chip mounting surface 1a of the heat sink 1.
The semiconductor chip 6 is mounted on the heat sink 1 by a heat conductive adhesive 7. 4 is TAB
These are solder balls of the tape 3.

Further, the heat radiating plate 1 radiates heat of the semiconductor chip 6 and is made of a metal having a high thermal conductivity, for example, a copper alloy or stainless steel, or a glass epoxy material.

The heat radiating plate 1 is provided with a rectangular or circular opening 8 as required. The opening 8 is provided in the frame-type reinforcing plate 2.
The opening 8 is provided near the corner of the space 2a.
Is to easily discharge moisture or water vapor that has entered the space 2a of the frame-shaped reinforcing plate 2 by a manufacturing process of the semiconductor device or washing at the time of mounting the substrate, and furthermore, the sealing resin 5 or the high thermal conductive adhesive 7 It is provided to release a gas generated when the resin is cured to the outside. Therefore, the opening 8 is provided so as to be separated from the outer edge of the semiconductor chip 6 to the outside so that the opening edge is not closed by the sealing resin 5 or the high thermal conductive adhesive 7.

Further, the first embodiment of the present invention is characterized in that an opening 9 separate from the opening 8 is provided in the heat sink 1.

The opening 9 is for visually confirming the state of application of the high thermal conductive adhesive 7 to the semiconductor chip 6, and the outer periphery 6 a of the semiconductor chip 6 adhered to the heat sink 1.
Are provided on the heat radiating plate 1 corresponding to the positions of. The openings 9 are desirably provided in correspondence with the outer periphery 6a of all four sides of the semiconductor chip 6, and the dimensions of the openings 9 are
In order not to impair the heat diffusion efficiency, the width of the opening is as narrow as possible and the length of the opening is one of the semiconductor chips 6.
It is desirable that the length be about one third of the length of the outer periphery 6a of the side.

Further, the opening 9 is provided with the opening 8,
The high thermal conductive adhesive 7 is provided at a position avoiding the diagonal lines L ₁ and L ₂ connecting the high-concentration lines 8 and spreads in the diagonal lines L ₁ and L ₂ .

Therefore, according to the first embodiment of the present invention, when the semiconductor chip 6 is mounted on the chip mounting surface 1a of the heat radiating plate 1 with the high thermal conductive adhesive 7, the adhesive 7 Along the outer periphery 6 a side, and penetrates into the opening 9.

In the first embodiment of the present invention, the state of application of the adhesive 7 to the semiconductor chip 6 through the opening 9 is visually checked. If the adhesive 7 penetrates into the opening 9, it means that the adhesive 7 has been applied to the entire back surface of the semiconductor chip 6, and the adhesive 7 must penetrate and fill some of the openings 9. For example, it is visually confirmed that the adhesive 7 on the back surface of the semiconductor chip 6 is insufficient.

Further, since the opening 9 is provided corresponding to the outer periphery 6a of the semiconductor chip 6, even if the adhesive 7 is excessive, a part thereof is absorbed into the opening 9, The adhesive 7 does not protrude beyond the outer periphery 6a of the semiconductor chip 6 and is not applied.

Since the opening 9 is provided so as to avoid the corner of the semiconductor chip 6, the adhesive 7 spreads toward the corner of the semiconductor chip 6, and
The area of application of the adhesive 7 to the adhesive can be increased to increase the heat diffusion efficiency.

The first embodiment shown in FIG. 1 shows an example in which the heat dissipation plate 1 is provided with an opening 8 having a rectangular or circular shape.
As described above, the first embodiment can be similarly applied to a structure in which the opening 8 is not provided in the heat sink 1. That is, the heat radiating plate 1 only needs to have a rectangular or circular opening 8 as required, and the heat radiating plate 1 does not necessarily have to have the opening 8 in order to exhibit the effect of the first embodiment of the present invention. is not.

(Embodiment 2) FIG. 2A is a plan view showing Embodiment 2 of the present invention, and FIG.
FIG. 3A is a sectional view taken along line A ′, and FIG. 3C is a sectional view taken along line BB ′ in FIG.

In the second embodiment of the present invention shown in FIG. 2, an elongated opening 10 is provided from the corner of the semiconductor chip 6 to the corner of the space 2a of the frame-shaped reinforcing plate 2.

The opening 10 according to the second embodiment of the present invention
It has both functions of the openings 8 and 9 according to the first embodiment shown in FIG. In other words, of the openings 10 according to the second embodiment, the opening outside the semiconductor chip 6 has a function of visually monitoring the application state of the heat conductive adhesive 7, and also has a function during a semiconductor device manufacturing process or during board mounting. It has a function of easily discharging moisture or water vapor that has entered under the heat radiating plate 1 by washing or the like, and releasing a gas generated when the sealing resin 5 or the high thermal conductive adhesive 7 is cured to the outside. I have. Further, the opening 10 located on the semiconductor chip 6
Has a function of visually confirming the applied amount of the heat conductive adhesive 7.

When the opening 10 is provided, the position of the portion of the inner end of the opening that contacts the semiconductor chip 6 is determined by the heat conductive adhesive 7.
Must be provided so as to overlap at least the outermost periphery of the range where the application is required. However, in order to prevent a decrease in the heat diffusion efficiency, it is desirable that the opening size is as small as possible.

The opening 10 according to the second embodiment does not have the effect of suppressing the spread of the adhesive 7 among the functions of the opening 9 shown in FIG.
Since it is simpler than that of the heat sink, the cost can be reduced when processing the heat sink. Further, since the opening 10 of the heat radiating plate 1 on the semiconductor chip 6 is located only at the corner, there is an advantage that a decrease in heat diffusion efficiency can be prevented.

[0034]

As described above, according to the present invention, overapplication of the heat conductive adhesive can be eliminated. The reason for this is that the application amount of the adhesive, which was conventionally simply controlled by weight, can be easily confirmed visually by visualizing the application range for each assembly lot.
This is because the application area of the adhesive can be quantified.

Further, the adhesive can be spread and applied to the corners of the semiconductor chip. The reason is that by optimizing the position of the opening for visual confirmation, the spread of the adhesive can be expanded from a circle to a shape close to a square.

Further, the material cost of the heat conductive adhesive can be reduced. The reason for this is that the amount of adhesive that has been conventionally applied in a large amount can be reduced to an optimum amount.

[Brief description of the drawings]

FIG. 1A is a plan view showing a first embodiment of the present invention,
(B) is a cross-sectional view taken along the line AA ′ of (a), (c) is
It is a BB 'line sectional view of (a).

FIG. 2A is a plan view showing a second embodiment of the present invention,
(B) is a cross-sectional view taken along the line AA ′ of (a), (c) is
It is a BB 'line sectional view of (a).

3A is a plan view showing a modification of the first embodiment of the present invention, FIG. 3B is a cross-sectional view taken along line AA ′ of FIG. 3A, and FIG.
FIG. 3A is a cross-sectional view taken along line BB ′ of FIG.

FIG. 4A is a plan view showing a conventional example, and FIG.
(A) is a cross-sectional view taken along line AA ′, and (c) is a cross-sectional view taken along line B- in (a).
It is a sectional view taken on the line B '.

FIG. 5A is a plan view showing another conventional example, and FIG.
Is a cross-sectional view taken along the line AA ′ of (a), and (c) is a cross-sectional view of B of (a).
FIG. 4 is a sectional view taken along line -B ′.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat sink 1a Chip mounting surface 2 Frame type reinforcing plate 2a Space 3 TAB tape 4 Solder ball 5 Sealing resin 6 Semiconductor chip 6a Outer periphery of semiconductor chip 7 Thermal conductive adhesive 8 Opening 9 Opening 10 Opening

Claims (1)

(57) [Claims] 1. A semiconductor device having a semiconductor chip and a radiator plate, wherein the semiconductor chip is mounted on the radiator plate with a thermally conductive adhesive, and the radiator plate removes heat generated in the semiconductor chip. Having an opening, the opening corresponding to the outer periphery of the semiconductor chip,
A semiconductor device for visually confirming a state of application of a high-temperature conductive adhesive near an outer periphery of a semiconductor chip.