JPH0521648A - Semiconductor device - Google Patents

Abstract

(57) [Abstract] [Purpose] The gap between the island and the heat dissipation heat conductor is kept constant against the injection pressure at the time of molding, and a void is created between the island and the heat dissipation heat conductor. By satisfactorily filling the melt sealing material between the both without doing so, the heat dissipation effect is enhanced. [Structure] The semiconductor chip 1 and the inner lead 3a are connected by a thin metal wire 4. A heat-dissipating heat conductor 5 is arranged to face the island 2 on which the semiconductor chip 1 is mounted with a small space therebetween. Except for the outer leads 3b, the whole is covered and solidified with the sealing material 6. The opening 8 and the bending projecting piece 9 are formed by cutting and raising in the main body portion 5a of the heat dissipation heat conductor 5, and the bending projecting piece 9 is brought into contact with the island 2 so that the sealing material 6 has an injection pressure during molding. On the contrary, the gap between the heat dissipation heat conductor 5 and the island 2 is kept constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a structure in which a semiconductor chip mounted and held on an island and an inner lead of a lead frame are connected to each other via a fine metal wire, and a heat conduction for heat dissipation is provided at a small interval on the island. The present invention relates to a semiconductor device in which the bodies are opposed to each other and the island, the semiconductor chip, the thin metal wires, the inner lead, and the heat dissipation heat conductor are covered with a sealing material and solidified except for the outer leads of the lead frame.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing a conventional semiconductor device of this type.

In the figure, 1 is a semiconductor chip, 2 is an island for mounting and holding the semiconductor chip 1, 3 is a lead frame, 3a is an inner lead in the lead frame 3, 3b is an outer lead in the lead frame 3,
Reference numeral 4 is a thin metal wire that electrically connects an electrode (not shown) on the semiconductor chip 1 to the inner lead 3a. Reference numeral 5 is a heat-dissipating heat conductor that is arranged to face the island 2 with a small space therebetween.
Reference numeral 6 denotes an encapsulating material which is solidified in a state in which the semiconductor chip 1, the island 2, the inner leads 3a, the fine metal wires 4 and the heat dissipation heat conductor 5 are covered for protection except the outer leads 3b of the lead frame 3.

The heat dissipating heat conductor 5 is, as shown in FIG.
It is composed of a main body portion 5a and four corner heat radiation portions 5b, and the end portions of the heat radiation portion 5b are exposed at the outer peripheral surface of the sealing material 6. The heat radiating portion 5b is separated from the inner lead 3a.

Next, the operation will be described.

When the current is supplied to the semiconductor chip 1, the semiconductor chip 1 starts to generate heat. The heat propagates from the island 2 to the heat-dissipating heat conductor 5 through the sealing material portion 6a filled between the island 2 and the heat-dissipating heat conductor 5, and then from the heat-dissipating heat conductor 5. It is released to the outside through the heat dissipation portion 5b. That is, abnormal temperature rise of the semiconductor chip 1 is prevented by heat dissipation due to heat conduction through the heat dissipation heat conductor 5, and malfunction of the semiconductor chip 1 is avoided to improve reliability.

[0007]

In the conventional semiconductor device, as shown in FIG. 4, the main body portion 5a of the heat dissipating heat conductor 5 has a flat plate shape with no openings, protrusions or irregularities over the entire surface. It was the one. Therefore, it causes the following problems.

That is, when the sealing material 6 is molded and set in the cavity of the molding die, and the molten sealing material is injected into the cavity, the injection pressure at that time causes heat conduction for heat dissipation. The body 5 is pushed toward the side closer to the island 2 and the gap between the island 2 and the heat dissipation thermal conductor 5 is reduced.

As a result, the gap between the island 2 and the heat dissipating heat conductor 5 is insufficiently filled with the molten sealant, and voids (spaces, bubbles) 7 are formed in the sealant portion 6a in the gap. Occurs, and the voids 7 reduce the thermal conductivity of the sealing material portion 6a, which lowers the heat dissipation effect as a whole.

The present invention was devised in order to solve the above-mentioned problems, and a molten sealing material is provided between the island and the heat-dissipating heat conductor in a state where no void is generated between them. It is an object of the present invention to obtain a semiconductor device in which is filled well.

[0011]

In order to achieve the above-mentioned object, the present invention has a structure in which a semiconductor chip mounted and held on an island and an inner lead of a lead frame are connected to each other via a thin metal wire. A heat radiation heat conductor is arranged to face each other with a small space between the island, the semiconductor chip, the metal wires, the inner leads and the heat radiation heat conductor except for the outer leads of the lead frame. The solidified semiconductor device has the following configuration.

In the semiconductor device according to the present invention, an opening is formed by cutting and raising in a portion of the heat dissipation heat conductor facing the island, and a bending protrusion protruding toward the island is formed. It is characterized in that the piece is brought into contact with the island.

[0013]

According to the above construction of the present invention, since the bending protrusion cut and raised from the heat dissipating heat conductor is brought into contact with the island, the injection pressure of the molten sealing material at the time of molding the sealing material is improved. The heat-dissipating heat conductor can be held at a predetermined position against the heat, and a reduction in the gap between the island and the heat-dissipating heat conductor is avoided. And, by preventing the reduction of the gap distance, the molten sealing material can be favorably flowed into the gap from the periphery of the heat dissipation heat conductor.

Further, an opening portion is formed by cutting and raising at the base portion of the bending protrusion, and the molten sealing material directly flows into the gap through this opening portion, so that as a whole, The molten sealant is well filled in the gap between the island and the heat dissipation heat conductor.

[0015]

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

FIG. 1 is a sectional view showing a semiconductor device according to an embodiment of the present invention, and FIG. 2 is a perspective view of a heat dissipation heat conductor to be embedded in the semiconductor device.

The semiconductor chip 1 is placed and held on the island 2, and each inner lead 3a in a plurality of lead frames 3 arranged around the semiconductor chip 1 and the corresponding electrodes on the semiconductor chip 1 (not shown). ) Are electrically connected to each other by a thin metal wire (bonding wire) 4 such as Au.

The heat radiating heat conductor 5 is arranged on the back surface side of the island 2 so as to be opposed to the island 2 with a small space therebetween.
The one shown in is used.

That is, in the heat dissipating heat conductor 5, four opening portions 8 are formed by cutting and raising the main body portion 5a at four locations of the main body portion 5a facing the island 2, and at the same time, bending protrusions projecting toward the island 2 side are formed. A piece 9 is formed. The opening areas of the four openings 8 are equal to each other,
Further, the cut-and-raised amounts (projection amounts) of the four bending protrusions 9 are also equal to each other.

The positions of the four openings 8 and the bending projections 9 are such that the two pairs of diagonal lines of the rectangular main body portion 5a of the heat-dissipating heat conductor 5 are line-symmetrical symmetrical centerlines. Is becoming Connecting the centers of the four openings 8 results in a rectangle or a square.

As shown in FIG. 1, the projecting end 9a of each bending projecting piece 9 is brought into contact with the back surface of the island 2. Since the four projecting ends 9 a contact the back surface of the island 2, the heat dissipation heat conductor 5 is kept parallel to the island 2.

Next, except for the outer leads 3b of the lead frame 3, the semiconductor chip 1, the island 2, the inner leads 3a, the fine metal wires 4 and the heat radiating heat conductor 5 are coated and solidified by molding of the sealing material 6. Obtain a semiconductor device.

During the molding, the injection pressure of the molten sealing material presses the heat dissipation heat conductor 5 toward the island 2, but the bending protrusion 9 due to the cutting and raising in the heat dissipation heat conductor 5 causes the island 2 to move. Since it is in contact with, the heat dissipation heat conductor 5 is held at the predetermined position against the injection pressure. That is, the gap between the heat dissipation heat conductor 5 and the island 2 is not reduced. Therefore, the molten sealing material can be favorably introduced into the gap from the periphery of the heat dissipation heat conductor 5. In addition, the molten sealing material directly flows into the gap through the opening 8 formed by cutting and raising.

By the above synergistic effect, the gap between the island 2 and the heat radiating heat conductor 5 can be sufficiently filled with the molten sealing material. Voids (spaces, bubbles) 7 as in the conventional example (see FIG. 4) are formed in the sealing material portion 6a in the gap.
(Refer to FIG. 4) is not generated, the thermal conductivity is avoided from being lowered, and the heat dissipation effect of the heat dissipation heat conductor 5 can be enhanced.

In the above embodiment, the cut-and-raised portions for the opening 8 and the bending protrusions 9 are four, but the present invention is not limited to this, and the cut-and-raised portions may be any number. It may be. Only one place is required. Also,
Not only in the case where one bending projecting piece 9 is cut and raised in one cut and raised portion, two bending projecting pieces 9 may be cut and raised from two opposite sides, and when the opening 8 is large, cutting is performed from four sides. You may wake it up.

[0026]

As described above, according to the present invention, a bending protrusion is formed by cutting and raising a heat dissipation heat conductor, an opening is formed at the same time, and the bending protrusion is brought into contact with the island to melt-seal. The heat dissipating heat conductor is held in place against the injection pressure of the stop material to prevent the gap between the island and the heat dissipating heat conductor from decreasing, and the melt sealing material from the periphery of the heat dissipating heat conductor to the gap is prevented. At the same time as improving the inflow, it was designed to promote the direct inflow of the molten sealant into the gap through the opening, so the molten sealant should be sufficiently filled as a whole as a whole. Therefore, it is possible to prevent the occurrence of voids in the sealing material portion between the island and the heat dissipation heat conductor. Therefore, the decrease in the thermal conductivity due to the void can be avoided, and the heat dissipation effect can be enhanced.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a heat dissipation heat conductor embedded in the semiconductor device of the embodiment.

FIG. 3 is a sectional view showing a conventional semiconductor device.

FIG. 4 is a perspective view of a heat dissipation heat conductor embedded in a conventional semiconductor device.

[Explanation of symbols]

1 Semiconductor Chip 2 Island 3 Lead Frame 3a Inner Lead 3b Outer Lead 4 Thin Metal Wire 5 Heat Dissipating Heat Conductor 5a Heat Dissipating Heat Conductor Main Body 5b Heat Dissipating Heat Conductor Joint 6 Encapsulant 6a Island and Heat Dissipating Sealing material portion between the heat conductor 8 Opening 8 Bending protrusion 9a Bending end of the bending protrusion

Claims (1)

Claim: What is claimed is: 1. A semiconductor chip mounted and held on an island and an inner lead of a lead frame are connected to each other via a thin metal wire, and heat is radiated to the island at a small interval. A semiconductor device in which conductors are arranged to face each other, and the island, the semiconductor chip, the thin metal wires, the inner leads, and the heat dissipation heat conductor are covered with a sealing material and solidified except for the outer leads of the lead frame, An opening is formed by cutting and raising in a portion of the heat dissipation heat conductor facing the island, and a bending projecting piece projecting to the island side is formed, and the bending projecting piece is brought into contact with the island. A semiconductor device characterized by.