JPH02244661A - Semiconductor device - Google Patents

Abstract

PURPOSE:To make a semiconductor device of this design uniform in heat dissipation and to reduce it in heat resistance so as to improve it in reliability by a method wherein two or more holes are provided to a cap, the protrusions of a heat dissipating member are fitted to the holes and fusion-welded together, and the heat dissipating member is soldered to the rear of a semiconductor chip. CONSTITUTION:Two or more L-shaped protrusions 16 are provided to a heat dissipating member 15 and fitted to the same L-shaped holes 18 provided to a cap 11, and a soldering material is soldered to the whole face of the protrusions 16, the rear of a semiconductor chip 2, and both the sides of the cap 11 to bond them together. By this process, the member 15 and the chip 2 are bonded together by soldering and soldered faces 18 are coincident with the holes 18 of the cap 11. Therefore, an air layer or oxide is prevented from penetrating into the rear part of the chip 2, so that heat is uniformly dissipated from the rear of the chip 2. The chip 2 and the member 15 are formed into an integral structure pinching the cap 11 between the chip 2 and the member 15, so that the cap 11 is increased in heat dissipation. By this setup, a semiconductor device of this design can be improved in reliability by making it uniform in heat dissipation and low in heat resistance.

Description

[Detailed Description of the Invention] [Summary] Regarding the mounting structure of a heat dissipation member in a surface mount type package, the purpose is to uniformly dissipate heat from a semiconductor chip and further reduce thermal resistance. A cap including at least one semiconductor chip electrically connected to a package substrate, a cap provided with a plurality of holes having a predetermined shape on the back surface of the semiconductor chip, and a plurality of protrusions fitting into the holes. The present invention is characterized in that it has a structure in which a heat dissipating member provided with a portion is welded to the semiconductor chip with the cap sandwiched therebetween.

(Industrial Field of Application) The present invention relates to a mounting structure for a heat dissipation member of a surface mount type package among semiconductor devices, particularly.

As semiconductor devices become more highly integrated and the power consumption of LSIs increases, the number of surface mount packages equipped with heat dissipation members is increasing, and there is a demand for further reduction in thermal resistance in such surface mount packages. has been done.

[Conventional technology] DIP (Dual
In1ine Package) type, PGA
(Piri Grotd Array) type, etc., 5OP (SLIIall 0utlin)
e Package) type, QFP (mouth uad Fl
at Package) type, L CC (Lea
Although surface mount types such as dtess Chip Carri, er) types are known, the semiconductor chips mounted in these high-density packaging packages are mainly flip chips or face-down type semiconductor chips such as tab type. At that time, a heat dissipation member is provided for the purpose of improving heat dissipation from the semiconductor chip, and a configuration is adopted in which the heat generated in the semiconductor chip is transferred from the back of the chip to the heat dissipation member, and the heat is radiated from the surface. There is. .

As a conventional example of a high-density actual device C package provided with such a heat dissipation member, a PGA type semiconductor device is shown in FIGS. FIG. 3(b) is a perspective view of the heat dissipation member, and FIG. 3(C) is the same figure (
It is a CC sectional view of a). Symbol 1 in the diagram is a cap, 2
3 is a semiconductor chip, 3 is a substrate, 4 is a lead bin, 5 is a heat dissipation member, and 6 is a welding material. A large number of bump electrodes 7 are provided on the surface of the semiconductor chip 2 shown in this figure, and these bump electrodes 7 are connected to wiring arranged on the surface of the substrate 3, and are led out to the lead bin 4 through multilayer wiring and via holes made in the substrate. are doing.

The heat dissipation member 5 is made of aluminum or copper, which has good thermal conductivity. FIG. 2, a heat dissipating member 5 is bonded to the entire surface by melting a welding material 6. The welding material 6 has a composition of Pb:5, for example.
Pb/Sn alloy solder with n=9:1 and Au/Sr+eutectic alloy solder are used, and the melting point of these welding materials 6 is about 3
It is 00°C.

[Problem to be solved by the invention]

By the way, as shown in FIG. 3(C) above, in the conventional semiconductor device, a heat dissipating member is welded to the entire back surface of the semiconductor chip using a welding material 6, and the large bonding surface improves thermal conductivity. However, it is difficult to uniformly bond the entire surface to be bonded, and air spaces may become trapped in the welding material, or oxides generated when the welding material is melted may cause the bonding surface to deteriorate. Unfortunately, the large area leaves no space for air and oxides to escape, resulting in an uneven bonding surface and an increase in the thermal resistance of the semiconductor device.

The present invention solves these serious problems and proposes a semiconductor device that uniformly dissipates heat from a semiconductor chip and further reduces thermal resistance.

[Means to solve the problem]

The problem is to have at least one semiconductor chip 2 electrically connected to a package substrate with its surface facing downward, as in the embodiment shown in FIGS. A plurality of holes 18.2 having a predetermined shape
A heat dissipating member 25.8 is provided with a cap 11.degree. 21 provided with a plurality of protrusions 16.degree.
26 is solved by a semiconductor device having a structure in which the cap is sandwiched and welded to the back surface of the semiconductor chip.

[For production]

That is, the present invention provides a plurality of portions of the heat dissipation member to be welded to the back surface of the semiconductor chip (portions consisting of holes of a plurality of caps), and the protrusions of the heat dissipation member are fitted into the portions to weld the semiconductor chip and the heat dissipation member. Weld together.

By doing so, when the welding material is melted at the welded portion, the fluidity increases and the air layer and oxide are removed in a floating state, improving the adhesion at the protrusion. As a result, heat dissipation from the back surface of the semiconductor chip is made uniform, and with this configuration, the semiconductor chip, the cap, and the heat dissipation member are integrated, so there is an advantage that heat dissipation from the cap is increased.

〔Example] Examples will be described in detail below with reference to the drawings.

1(a) to 1(C) show cross-sectional views of the embodiment (1) according to the present invention, FIG. 1(a) is a sectional view, and FIG. Figure 1 (C) is A in Figure 1 (a).
It is an A sectional view. In the figure, symbol 11 is a cap, 15 is a heat radiating member, 16 is a key-shaped protrusion of the heat radiating member, and other symbols are the same parts as in FIG. 3 with the same symbols.

That is, as is clear from the perspective view shown in FIG. They are fitted into a plurality of holes, and the welding material 6 is welded to the entire surface of the protrusion, the back surface of the semiconductor chip 2, and both surfaces of the cap 11 to join them.

FIG. 1C shows four welding surfaces 18 between the heat dissipating member 15 and the semiconductor chip 2, and the semiconductor chip and the heat dissipating member 15 are welded and joined using the welding material 6 on these welding surfaces.

Moreover, this welding surface 18 corresponds to the hole in the cap 11.

In this way, at least the back surface portion of the semiconductor chip to which the key-shaped protrusion 16 is welded will not be trapped by an air layer or oxide, and therefore, heat dissipation from the back surface of the semiconductor chip will be more likely to be uniform. Furthermore, since the cap is sandwiched and the semiconductor chip, the cap, and the heat radiating member are integrally welded, heat dissipation from the cap is also increased.

The cap 11 having such a shape can be easily formed by punching holes using a rolling mill, and the heat dissipating member 15 can also be shaped using a rolling mill.

Next, FIGS. 2(a) to (C) show examples (
2(a) is a sectional view of the heat dissipating member, FIG. 2(C) is a perspective view of the heat dissipation member, and FIG.
It is a BB sectional view of a). Symbol 21 in the figure is a cap.

25 is a heat dissipation member, 26 is a circular protrusion of the heat dissipation member, and the other symbols are the same parts as in FIG. 3 and FIG. As is clear from the perspective view shown in FIG. And semiconductor chip 2 back, welding material 6 on both sides of cap 21
weld.

FIG. 2(C) shows 12 parts of the heat dissipating member 25 and the semiconductor chip 2.
A welding surface 28 is shown, on which the semiconductor chip and the heat dissipating member 25 are welded together using the welding material 6, and similarly, the welding surface 2 becomes a hole at the relative position of the cap 21.

In this way, the heat dissipation from the back side of the semiconductor chip is also made uniform, and the heat dissipation performance is improved, leading to improved reliability of the semiconductor device.

Although two embodiments have been described above, embodiments using heat dissipating members having various other shapes can also be considered, and uniformity of heat dissipation can be similarly obtained.

(Effects of the Invention) As is clear from the above explanation, according to the semiconductor device according to the present invention, the heat dissipation performance is improved and heat is dissipated uniformly from the semiconductor chip, the thermal resistance is further reduced, and the reliability thereof is improved. This greatly contributes to improvement.

The figures shown in FIGS. 3(a) to 3(C) are diagrams showing a conventional semiconductor device.

In the figure, 1, 11.21 is the cap, 2 is a semiconductor chip, 3 is the board, 4 is the lead pin, 5, 15.25 is a heat dissipation member, 6 is welding material, 8, 18.28 is the welding surface (hole), 16 and 26 are protrusions It shows.

[Brief explanation of drawings]

FIGS. 1(a) to (C) are diagrams showing embodiment (1) according to the present invention, and FIGS. 2(a) to (C) are diagrams showing embodiment (II) according to the present invention.
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Claims (1)

[Claims] A cap (11, 21) has at least one semiconductor chip (2) electrically connected to a package substrate with the surface facing downward, and a plurality of holes having a predetermined shape are provided on the back surface of the semiconductor chip. A heat dissipation member (15,
25) is welded to the semiconductor chip with the cap sandwiched therebetween.