JPH11233695A - Semiconductor device - Google Patents

Abstract

[PROBLEMS] To improve the heat dissipation of a path for conducting heat generated from a small semiconductor chip to a printed circuit board. SOLUTION: An Au bump 4 is formed on an Al electrode in an outer peripheral portion of a semiconductor chip 1, and an additional bump 7 made of gold is formed on a portion of the semiconductor chip 1 irrelevant to wiring connection. Further, the electrodes 3 corresponding to the Au bumps 4 of the semiconductor chip 1 and the electrodes 8 corresponding to the additional bumps 7 are also formed on the printed board 2 side. Then, the Au bump 4 and the electrode 3 and the additional bump 7 and the electrode 8 are connected by the conductive adhesive 5 and mounted. Further, after mounting, the semiconductor chip 1 and the printed board 2 are used to maintain strength.
Is hardened by the sealing resin 6. As a result, the contact area of gold, which is a member having high thermal conductivity, in the semiconductor chip 1 is increased, so that heat dissipation can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device having a small semiconductor chip mounted on a printed circuit board.

[0002]

FIG. 8 is a plan view of a conventional semiconductor device, and FIG.
8 is a sectional view taken along the line AA in FIG. 8, wherein 1 is a semiconductor chip, 2 is a printed board, 3 is an electrode on the printed board 2, 4 is an Au bump formed on an electrode of the semiconductor chip 1, and 5 is a conductive adhesive. , 6 indicate a sealing resin. The circles in FIG. 8 indicate the portions where the Au bumps 4 are formed.

[0003] Al electrodes are provided on the outer peripheral portion of the semiconductor chip 1, and Au bumps 4 are formed on these Al electrodes. Also, on the printed circuit board 2 side, corresponding electrodes are formed on the Al electrodes of the semiconductor chip 1. When a small semiconductor chip 1 typified by a bare chip is mounted on a printed circuit board 2, a conductive layer is formed between the Au bump 4 on the Al electrode of the semiconductor chip 1 and the electrode 3 on the printed circuit board 2. They are connected by an adhesive 5 and mounted. Further, after the mounting, the space between the semiconductor chip 1 and the printed circuit board 2 is hardened by a sealing resin 6 to maintain strength.

[0004]

By the way, as the semiconductor chip becomes smaller, the heat generation density of the chip increases. Therefore, improvement in heat dissipation is a design issue.

[0005] The main path for transferring heat from a semiconductor chip is:
Heat transfer from the chip surface to the air and heat conduction from the sealing resin and the Au bumps to the printed circuit board. Here, it is considered that the influence of radiation is small.

[0006] Considering the heat conduction which greatly affects the heat radiation, the heat conductivity of the resin is very poor, and the heat conductivity of Au is very high. However, in the conventional semiconductor device, the Au area is smaller than the resin area, and as a result, the effect of heat dissipation by heat conduction is small.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a semiconductor device in which heat generated from a small semiconductor chip is conducted to a printed circuit board with improved heat radiation.

[0008]

In order to achieve the above object, according to the present invention, a bump is formed on an electrode of a semiconductor chip, and the bump is connected to an electrode on a substrate side with a conductive adhesive. In a semiconductor device in which a gap between a chip and the substrate is solidified with a sealing resin, a portion of the semiconductor chip irrelevant to a wiring connection with the substrate, for conducting heat of the semiconductor chip to the substrate, A member having higher thermal conductivity than the sealing resin is provided. With such a configuration, the area where a member having a high thermal conductivity comes into contact with the semiconductor chip increases, and in addition to the heat radiation from the semiconductor chip electrodes via the bumps and the electrodes on the substrate side, the heat generation of the semiconductor chip is also reduced. Because it can conduct heat to the substrate side and release it through a member with high conductivity,
Heat dissipation is improved.

Further, the present invention is characterized in that a plurality of additional bumps made of the member having a high thermal conductivity are formed on the semiconductor chip, and these additional bumps are connected to the substrate with a conductive adhesive. I do. According to such a configuration, a member having high thermal conductivity can be reliably provided for a small semiconductor chip.

The present invention is characterized in that the bumps of the electrodes of the semiconductor chip and the additional bumps are formed of the same material. With such a configuration, additional bumps can be formed on the semiconductor chip during the step of forming the bumps of the electrodes of the semiconductor chip.

Further, the present invention is characterized in that the member having a high thermal conductivity is formed of gold. With such a configuration, stable heat conduction can be ensured.

Further, the present invention is characterized in that the member having high thermal conductivity is formed of solder. With such a configuration, a member having high thermal conductivity can be formed at low cost.

Further, the present invention is characterized in that the diameter of the bump of the electrode of the semiconductor chip is different from the diameter of the additional bump. With such a configuration, for example, by providing a large number of additional bumps having a small diameter or increasing the diameter, the contact area of a member having high thermal conductivity in the semiconductor chip can be increased.

Further, the present invention is characterized in that a hole is provided at a position of the semiconductor chip on the substrate. With such a configuration, the surface area of the printed circuit board in the vicinity of the semiconductor chip is increased, and heat radiation to the outside can be improved.

Further, the present invention is characterized in that a through hole is provided in a portion of the substrate facing the additional bump, and a material having high thermal conductivity is filled in the through hole. With such a configuration, since the filling member in the through hole has high thermal conductivity, the heat of the semiconductor chip conducted through the additional bump can be efficiently radiated through the filling member in the through hole. .

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. It should be noted that the same members as those of the prior art shown in FIG.

FIG. 1 is a plan view of a semiconductor device according to the present invention, and FIG.
Is a cross-sectional view taken along the line BB of FIG. 1, 7 denotes an additional bump, 8 denotes an electrode, and the additional bump 7 is formed of gold. In FIG. 1, white circles indicate portions where the Au bumps 4 are formed, and black circles indicate portions where the additional bumps 7 are formed.

As shown in FIG. 1, an Au bump 4 is formed on an Al electrode on an outer peripheral portion of the semiconductor chip 1, and an additional bump 7 is formed on a central portion of the semiconductor chip 1. Further, the electrodes 3 corresponding to the Au bumps 4 of the semiconductor chip 1 are formed also on the printed board 2 side, and the electrodes 8 corresponding to the additional bumps 7 are similarly formed.

Then, the Au bumps 4 and the electrodes 3 and the additional bumps 7 and the electrodes 8 are connected by a conductive adhesive 5 and mounted. Further, after the mounting, the space between the semiconductor chip 1 and the printed circuit board 2 is hardened by a sealing resin 6 to maintain strength. Here, since the additional bump 7 is formed at a portion other than the Al electrode of the semiconductor chip 1,
There is no electrical connection between the additional bump 7 and the semiconductor chip 1. The electrode 8 is independent of other wiring patterns on the printed circuit board 2, and there is no electrical connection between the electrode 8 and another wiring pattern on the printed circuit board 2.

FIG. 3 is a graph showing heat radiation characteristics of the semiconductor device. This graph shows the ratio of the total number of bumps (the number of Au bumps 4 + the number of additional bumps 7) when the number of Au bumps 4 is 1. FIG. As shown in FIG. 3, as the number of additional bumps 7 increases, the temperature rise value decreases, and it can be seen that the heat dissipation by heat conduction is improved.

With this configuration, the heat radiation path is widened by the amount corresponding to the provision of the additional bumps 7, so that the heat radiation of the printed circuit board is improved. Further, by forming the additional bumps 7 from gold, the additional bumps 7 can be formed in the step of forming the Au bumps 4 on the Al electrodes of the semiconductor chip 1.

Incidentally, the additional bump 7 is not limited to the above-described configuration. For example, the Au bump 4 may be formed to have a larger diameter than that of the Au bump 4, and such a formation may increase the area ratio of the bump to the sealing resin 6 in the semiconductor chip 1 and improve heat dissipation. it can. Also, the material of the additional bump 7 is not limited to gold, and any material having a high thermal conductivity such as solder can improve heat dissipation. Further, instead of the additional bumps 7, as shown in FIG. 4, a desired shape such as a plate shape, a lattice shape, a string shape, a perforated plate shape made of a member having high thermal conductivity such as gold or solder is formed. The same effect can be obtained by providing the heat dissipation pattern or the like on the semiconductor chip 1.

FIG. 5 is a sectional view showing a main part of a semiconductor device according to a second embodiment of the present invention, and 9 indicates a hole. The hole 9 is provided on the surface of the printed circuit board 2 opposite to the mounting surface of the semiconductor chip 1 and below the electrode 8. The same members as those in the semiconductor device of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description is omitted.

With such a configuration, the hole 9
, The surface area of the printed board 2 is increased, and the heat conducted from the semiconductor chip 1 to the printed board 2 can be efficiently released. Further, the portions of the electrodes 3 and the electrodes 8 on the printed board 2 become hot, but since the holes 9 are provided below the electrodes 8, the thickness of the portions of the electrodes 8 on the printed board 2 is thinner than other portions. As a result, heat at the site of the electrode 8 is easily released to the outside through the hole 9, and the heat dissipation is further improved.

FIG. 6 is a sectional view showing a main part of a semiconductor device according to a third embodiment of the present invention. Reference numeral 10 denotes a through hole formed in a portion of the printed circuit board 2 facing the additional bump 7;
Reference numeral 11 denotes a filling member for filling the through hole 10, and reference numeral 12 denotes ground steel constituting a predetermined layer in the printed circuit board 2 having a multilayer structure. The same members as those in the semiconductor device of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description is omitted.

The electrode 8 is formed from the surface of the printed circuit board 2 on which the semiconductor chip 1 is mounted to the inner wall of the through hole 10, and the electrode 8 and the ground steel are connected in the through hole 10. The filling member 11 fills the inside of the through hole 10 in which the electrode 8 is formed. Here, as shown in FIG. 6, the diameter of the through hole 10 is set to be larger than that of the additional bump 7, so that the additional bump 7 is connected to the filling member 11 via the conductive adhesive 5. As the material of the filling member 11, a metal having good heat conductivity such as tungsten is suitable.

With this configuration, the heat generated in the semiconductor chip 1 is transferred to the additional bump 7 and the filling member 1.
1 can radiate heat to the outside of the printed circuit board 2. In addition, since both the additional bump 7 and the filling member 11 are made of a metal having good heat conductivity, the heat dissipation is improved.

In the configuration shown in FIG. 6, the diameter of the through hole 10 is set larger than that of the additional bump 7, but the diameter of the through hole 10 may be set smaller than the diameter of the additional bump 7. . Also, in this case,
As shown in FIG. 7, the additional bump 7 blocks the through hole 10, so that the sealing member 6 does not flow into the through hole 10, and is printed from the additional bump 7 without filling the filling member 11. Heat can be radiated to the outside of the substrate 2.

[0029]

According to the present invention having the above-described structure, a member having a high thermal conductivity is provided at a portion of the semiconductor chip which is irrelevant to the wiring connection with the substrate.
Since the area of the high thermal conductivity member in contact with the semiconductor chip increases, the heat of the semiconductor chip can be released to the substrate side through the high thermal conductivity member, thereby improving heat dissipation. Can be.

[Brief description of the drawings]

FIG. 1 is a plan view of a semiconductor device of the present invention.

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

FIG. 3 is a graph showing heat radiation characteristics of a semiconductor device;

FIG. 4 is an explanatory view showing an example of a member provided on a semiconductor chip instead of an additional bump.

FIG. 5 is a sectional view showing a main part of a semiconductor device according to a second embodiment of the present invention;

FIG. 6 is a sectional view showing a main part of a semiconductor device according to a third embodiment of the present invention;

FIG. 7 is a sectional view showing a main part of another example of the semiconductor device according to the third embodiment of the present invention;

FIG. 8 is a plan view of a conventional semiconductor device.

FIG. 9 is a sectional view taken along the line AA in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Printed circuit board 3, 8 electrode 4 Au bump 5 Conductive adhesive 6 Sealing resin 7 Additional bump 9 Hole 10 Through hole 11 Filling member

Claims (8)

[Claims] A bump formed on an electrode of the semiconductor chip;
Connect this bump and the electrode on the substrate side with a conductive adhesive,
Further, in a semiconductor device in which a space between the semiconductor chip and the substrate is solidified with a sealing resin, heat of the semiconductor chip is transferred to the substrate in a portion of the semiconductor chip irrelevant to a wiring connection with the substrate. A semiconductor device having a higher thermal conductivity than the sealing resin. 2. The semiconductor device according to claim 1, wherein a plurality of additional bumps made of the member having high thermal conductivity are formed on the semiconductor chip, and the additional bumps are connected to the substrate with a conductive adhesive. 2. The semiconductor device according to 1. 3. The semiconductor device according to claim 2, wherein the bumps of the electrodes of the semiconductor chip and the additional bumps are formed of the same member. 4. The semiconductor device according to claim 1, wherein said member having a high thermal conductivity is formed of gold. 5. The semiconductor device according to claim 1, wherein said member having a high thermal conductivity is formed of solder. 6. The semiconductor device according to claim 2, wherein the diameter of the bump of the electrode of the semiconductor chip is different from the diameter of the additional bump. 7. The semiconductor device according to claim 1, wherein a hole is provided at a position of the semiconductor chip on the substrate.
7. The semiconductor device according to 3, 4, 5, or 6. 8. The semiconductor device according to claim 2, wherein a through hole is provided in a portion of said substrate facing said additional bump, and a material having a high thermal conductivity is filled in said through hole.