JPH02129951A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve the heat radiation performance of a resin-sealed package by a method wherein a heatsink is buried in the resin-sealed package and a plurality of joint parts which are used for jointing the heatsink with a lead frame at the time of assembly are provided at the corners of the resin-sealed package. CONSTITUTION:A heatsink 11 is buried in a resin-sealed package 24 and a semiconductor pellet 21 is bonded to the heatsink 11. The heatsink 11 has two or more joint parts 13 which are used for jointing the heatsink 11 with a lead frame at the time of assembly and the joint parts 13 are provided at the corners of the resin-sealed package 24. As the pellet 21 is directly brought into contact with the heatsink 11 without using a tab, therefore, the heat from the pellet 21 is radiated outside directly through the heatsink 11. With this constitution, subefficient heat radiation performance can be ensured.

Description

[Detailed Description of the Invention] [Industrial Application Field] Zero-blasting technology relates to semiconductor device manufacturing technology, particularly technology for improving the heat dissipation performance of pellets. Semiconductor integrated circuit devices (hereinafter referred to as ICs) require lower prices.

) Concerning what is effective when used.

[Conventional technology]

In general, ICs with large power consumption, such as so-called power ICs,
In C, a heat sink is built into a resin-sealed package. If the heat sink is integrated into the package, it will typically be mechanically and thermally coupled to the back side of the tab to which the pellet is bonded.

An example of a power IC with a built-in heat sink is "Bessatsu Micro Devices 2" published by Nikkei McGraw-Hill, June 11, 1980, P1.
35. There is.

In addition, since high-density, high-speed ICs used in computers require extremely high heat dissipation performance, for example, as described in Japanese Patent Application Laid-Open No. 110371/1983, semiconductor pellets are bonded to metals. A ceramic package type semiconductor device is used in which a heat sink is externally attached to a plate.

[Problem to be solved by the invention]

The technology of incorporating a heat sink into an IC package with a resin-sealed package as described above is limited by the package's external shape, so it is possible to use a technology with a small number of pins (leads) that allows for flexibility in designing the package's external shape. IC
Currently, it is only applied to (variety).

Furthermore, it is difficult to mass-produce a ceramic packaged semiconductor device with an external heat sink, making it difficult to reduce costs.

However, in recent years, as ICs have become more multi-mta, highly integrated, and faster, even surface-mounted ICs with a large number of bins are equipped with resin-sealed packages with built-in heat sinks that have good heat dissipation. development is required.

A first object of the present invention is to provide a semiconductor device equipped with a resin-sealed package having high heat dissipation performance.

The second object of the present invention is to have good productivity and mounting performance,
Another object of the present invention is to provide a semiconductor device that can be made smaller and have a higher number of bins at a lower price, and has high heat dissipation performance.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

An overview of typical inventions disclosed in this application is as follows.

That is, in a semiconductor device in which a plurality of leads electrically connected to a semiconductor pellet protrude from four sides of a resin-sealed package that is formed into a substantially rectangular planar shape, the interior of the resin-sealed package is At the same time, the semiconductor pellet is bonded to the heat sink, and at least two joints used for joining the lead frame during assembly are in the corners of the resin-sealed package. The configuration is such that they are arranged respectively.

[Effect]

According to the above-mentioned means, since the heat sink is in direct contact with the pellet without using a tab, the heat generated by the pellet is directly radiated to the outside through the heat sink, and sufficient heat dissipation performance is achieved. Secured.

The connection part of the heat sink with the lead frame is located at the corner of the rectangular resin-sealed package where there is plenty of space, so even if it has a built-in heat sink, it is possible to avoid increasing the size of the resin-sealed package. be able to.

In addition, since the pellet, lead group, and heat sink are resin-sealed in a resin-sealed package, external forces such as vibrations during transportation are avoided when this semiconductor device is mounted on a printed wiring board and after it is mounted. Even when added to this semiconductor device, accidents such as lead bending can be prevented from occurring, and as a result, the occurrence of short circuit defects and F7 gland defects can be avoided. Furthermore, since the resin-sealed package is suitable for mass production, costs can be reduced.

[Example] Figures 1 (a) and (b) are a front cross-sectional view and a cross-sectional end view along a diagonal line showing a resin-sealed MSP-IC which is an example of the present invention, and Figures 2 to 8. The figures are explanatory diagrams showing a method for manufacturing the MSP/IC, which is an embodiment of the present invention.

In this embodiment, the semiconductor device according to the present invention is a semiconductor S integrated circuit device (hereinafter referred to as IC) for realizing high-density packaging.
It is configured as an IC (hereinafter sometimes referred to as MSP-IC1 or simply IC) equipped with a resin-sealed mini square package.

This resin-sealed MSP/IC 25 includes a silicon semiconductor pellet (hereinafter referred to as pellet) 21, a plurality of glues 9 arranged on the four sides of the pellet, each electrode pad 21a of the pellet, and each lead. 9, a bonding wire 23 whose both ends are bonded and bridged, a heat sink 11 to which a pellet is bonded, and a package 24 which seals these with resin.
This MSP-IC is manufactured by the following manufacturing method.

Hereinafter, this resin-sealed MSP-
A method for manufacturing an IC will be explained. With this explanation, the MS
The details of the configuration of the P-IC will also be revealed.

In this embodiment, the multiple lead frame 1 shown in FIG. 2 is used in the method of manufacturing a resin-sealed MSP-IC. This multi-lead frame 1 is made of a thin plate made of a spring material having relatively high mechanical strength, such as iron-nickel alloy or phosphor bronze, and is formed by suitable means such as punching press working or etching process. The surface of the multi-lead frame 1 is plated with silver (Ag) to ensure proper wire bonding (not shown). figure). In this multi-lead frame 1, a plurality of unit lead frames 2 are arranged in a row in the lateral direction.

The unit lead frame 2 includes a pair of outer frames 3 having positioning holes 3a, and the outer frames 3 are arranged parallel to each other at predetermined intervals and extend in series. llJ! A pair of section frames 4 are disposed parallel to each other between both outer frames 3.3 and are integrally constructed between the unit lead frames 2.2, and are formed by these outer frames and section frames. A unit lead frame 2 is constructed within a substantially square frame body.

In each unit lead frame 2, a dam hanging member 5 is arranged approximately at right angles and integrally protrudes from the connecting portion of the outer frame 3 and the section par 4. The dam member 6 is arranged to have a substantially square frame shape and is integrally suspended. Each dam member 6 on the side of the section frame 4 has heat sink coupling members 7 arranged at four corners, and is integrally constructed in a substantially arcuate shape, and each heat sink coupling member 7 has a coupling hole 7a. It is located roughly in the center.

Further, a plurality of leads 9 are arranged on the dam member 6 at equal intervals in the longitudinal direction, and are integrally protruded parallel to each other and perpendicular to the dam member 6. The end portions each constitute an inner portion 9a by being arranged such that the tip thereof surrounds a receptacle space 8 for accommodating pellets, which will be described later. On the other hand, the ends of the outer extension portions of each lead 9 are separated from the outer frame 3 and the section frame 4 to form outer portions 9b. The portion of the dam member 6 between adjacent leads 9.9 substantially constitutes a dam 9a that blocks the flow of resin during package molding, which will be described later. This unit lead frame 2 is not provided with a tab provided in a normal lead frame and a tab suspension lead for suspending this tab from an outer frame or the like. That is, a cavity 8 is formed in the center of this unit lead frame 2 instead of a tab.

In this example, the MSP-IC manufacturing method includes a third
The heat sink 11 shown in the figure is used.

The heat sink 11 is made of a material with good thermal conductivity such as copper, and is formed into a substantially square shape that is larger than the planar shape of the pellet, and an annular groove is formed on the pellet mounting surface of the heat sink 11. 2 is multiple articles (in this example,
2) are arranged concentrically on the outside of the pellet, and are formed so as to surround the pellet and are respectively immersed. These annular grooves 12 extend the leak bus after molding the resin-sealed package, which will be described later, and are shape-bonded with the resin, thereby increasing the moisture resistance of the IC equipped with this resin-sealed package.

In addition, the heat sink IL has four coupling pieces 13 arranged at the four corners of a square and protruding radially in a substantially diagonal direction, and a coupling hole 13 is provided at the tip of each coupling piece 13.
A is opened to correspond to the coupling hole 7a of the lead frame. Each coupling piece 13 is bent into a crank shape on the way to the coupling hole 13a, and due to the bending of the coupling piece 13, the upper surface of the heat sink 11 is spaced a predetermined distance from the plane of the lead 9 group, as will be described later. It is now possible to do so.

As shown in FIG. 4, the multiple lead frame l and the heat sink 11 for electrical connection leads according to the above configuration are connected to the coupling hole 7a of the lead frame side coupling member 7,
The joint holes L3a of the heat sink side joint pieces 13 are arranged one above the other in an aligned state, and the rivets 14 are inserted into the rejoining holes 7a and 13a and fixed by caulking. are combined.

In the multiple lead frame polymer 20 in which each heat sink 11 is connected in this way, the lower heat sink 11 is opposed to the space 8 in the upper multiple lead frame 1, and the bending of the connecting piece IJ As a result, it is in a state where it does not come into contact with or interfere with the 9 groups of leads.

This multiple lead frame polymer 20 is subjected to a pellet bonding operation and then a wire bonding operation for each unit lead frame 2. These bonding operations are sequentially performed for each unit lead frame 2 by pitch-feeding the multiple lead frame polymer 20 in the lateral direction.

Then, as shown in FIGS. 5 and 6, the pellet bonding process produces a pellet 21 as a semiconductor integrated circuit structure into which an integrated circuit has been fabricated in the so-called pre-process of the semiconductor device manufacturing process. , disposed approximately at the center of each unit lead frame 2 on the heat sink 11, and bonded by being mechanically fixed by a bonding Ji22 formed between the heat sink 11 and the pellet 21. As a means for forming the pellet bonding layer, a gold-silicon eutectic layer,
For soldering, bonding and soldering methods using layers, silver paste adhesive layers, etc. can be used. However, if necessary, it is desirable to form a bonding layer so that it does not become a barrier to heat transfer from the pellet to the heat sink.

Subsequently, by a wire bonding operation, as shown in FIGS. 5 and 6, the electrode pad 21a of the pellet 21 bonded onto the heat sink 11,
Inner part 9 of lead 9 in each unit lead frame 2
The bonding wire 23 is bonded and bridged at both ends by using a suitable wire bonding device (not shown) such as an ultrasonic thermocompression wire bonding device or the like between the bonding wire 23 and the Ru.

Thereby, the integrated circuit built into the pellet 21 is electrically extracted to the outside via the electrode pad 2La, the bonding wire 23, and the inner part 9a and outer part 9b of the lead 9.

The lead frame polymer 20 that has been pelletized and wire bonded in this manner is molded into a package group in which each unit lead frame is resin-sealed using a transfer molding apparatus 30 as shown in FIG. The unit lead frames are simultaneously molded.

The transfer molding apparatus shown in FIG. 7 includes a pair of upper mold 31 and lower mold 32 that are clamped together by a cylinder device or the like (not shown).
A plurality of sets of upper mold cavity recesses 33a and lower mold cavity recesses 33b are respectively recessed in the mating surface with 2 so as to cooperate with each other to form the cavity 33. A bot 34 is provided on the mating surface of the upper mold 31, and a plunger 35, which is advanced and retracted by a cylinder device (not shown), is used to inject resin (hereinafter referred to as a molding material) into the bot 34 as a molding material.
It is inserted so that it can deliver resin.

A cull 36 is arranged and sunk in the mating surface of the lower die 32 at a position facing the bot 34, and a plurality of runners 37 are radially arranged and sunk so as to connect to the pots 34, respectively. ing. The other end of each runner 37 is connected to the lower cavity recess 3, 3b, respectively.
A gate 38 connects the resin to the cavity 33.
It is designed so that it can be injected into the body.

In addition, on the mating surface of the lower die 32, a relief recess 39 is formed in a rectangular shape slightly larger than the outer shape of the lead frame polymer 20 so that the thickness of the lead frame polymer 20 can escape, and is sunk to a constant depth with a dimension approximately equal to the thickness of the lead frame polymer 20. It is set up.

Further, in the bottom surface of the cavity recess 33b of the lower mold 32, an escape recess 33c is recessed at a constant depth and has a square shape approximately equal to the outer shape of the heat sink 11 so that the thickness of the bottom of the heat sink 11 can be slightly relieved. There is.

When transfusing a resin-sealed package using the multi-lead frame polymer 20 having the above structure, each cavity 33 in the upper mold 31 and lower mold 32 is formed between the four dam members 6 in each unit lead frame 2. correspond to the respective spaces.

During transfer molding, the multi-lead frame polymer 20 having the above structure is accommodated in the escape recess 39 recessed in the lower mold 32, and the pellets 21 of each unit lead frame 2 are accommodated in each cavity 33. It is arranged and set so that the At this time, heat sink 1
The bottom of the pellet 21 is inserted into the relief recess 33c sunk in the lower mold cavity recess 33b, and the pellet 21 is inserted into the cavity 33 while being bonded to the heat sink 11.
It is held within.

Subsequently, the upper mold 31 and the lower mold 32 are clamped, and the pot 3
4 as a molding material by the plunger 35.
0 is fed into each cavity 33 through the runner 37 and gate 38 and press-fitted.

After injection, when the resin 40 is thermoset and the resin-sealed package 24 is molded, the upper mold 31 and the lower mold 32 are opened, and the groups of packages 24 are separated by an ejector bin (not shown). be molded. In this way, as shown in FIG. 8, the multi-part frame polymer 20 into which packages 24 have been formed is removed from the transfer molding apparatus 30.

The pellet 21, the inner portion 9a of the lead 9, the bonding wire 23, and a portion of the heat sink 11 are sealed with resin inside the package 24 molded with resin in this manner.

In this state, one end surface of the heat sink 11 is exposed from the one end surface of the resin-sealed package 24 by an amount that is recessed into the escape recess 33c. Furthermore, the coupling pieces 13 and rivets 14 provided at each corner of the heat sink 11 are embedded inside the resin-sealed package 24, and the pair of proximal ends of the coupling member 7 are connected to the package 24. They are respectively protruded from the corner portions and suspended by the dam member 6.

Thereafter, in a lead cutting and forming step, the multi-lead frame polymer 20 is cut into the outer frame, the Cefsilane frame, the base end of the heat sink member 7, and After each dam 6a is cut off, the outer portion 9b of the lead 9 is bent into a lead shape by a lead forming device (not shown).

At this time, a pair of cuts of the heat sink coupling member 7 are formed at the corner portions of the package.

Resin-sealed MSP/IC2 manufactured as above
5 is mounted on a printed wiring board as shown in FIGS. 9 and 10.

In FIGS. 9 and 10, printed wiring board 26
A plurality of lands 27 are arranged so as to correspond to each part 9 of the resin-sealed MSP-IC 25 to be mounted, and are formed into a substantially rectangular thin plate shape using solder material. , 9 groups of leads of this IC 25 are aligned and abutted on this land 27, and each lead 9
and land 27 are electrically and mechanically connected by a solder mound layer 28 formed by reflow soldering.

Then, if necessary, a radiation fin (not shown) is attached to the heat sink 11 of the IC 25, or the heat sink 11 is held down to the printed wiring board #H, 26 by a presser (not shown). and fixed.

In this mounted state, when the IC 25 is operated and the pellet 21 generates heat, the heat is directly conducted from the pellet 21 to the heat sink 11.
Since heat is radiated to the outside air from the large surface area of the pellet 21, the pellet 21 is relatively sufficiently cooled. Also, heat sink 1
When the heat sink 1 is connected with heat dissipation fins, pressers, etc., the heat of the heat sink 11 is conducted to a wider range through the heat sink 11, and the heat dissipation effect becomes even higher.

According to the embodiment described above, the following effects can be obtained.

(1) By directly bonding the heat sink to the pellet without using a tab, the heat generated by the pellet can be directly transmitted to the heat sink and effectively released to the outside of the package, ensuring high heat dissipation performance. can do.

(2) By arranging the connection with the heatsink lead frame at the corner of the square in the mini square package, there is relatively more space in the corner, so even if the heatsink is built-in, the resin It is possible to avoid increasing the size of the sealed package, and it is possible to promote miniaturization, high density, and cost reduction.

Mortar) Separately from the leads for electrical connection, by bonding the pellet to a heat sink formed using a material with good thermal conductivity, the heat dissipation performance described in (1) above can be further improved.

(4) On the other hand, by forming the electrical connection leads separately from the heat sink using a material with high mechanical strength, it is possible to prevent the lead group from bending or breaking, and also to (3) makes it possible to ensure high heat dissipation performance.

(4) By resin-sealing the pellet, lead group, and part of the heat sink using a resin-sealed package, it is possible to prevent accidents such as lead bending, thereby preventing short circuits and disconnections. Occurrence can be avoided.

(5) By supporting the heat sink on a surface different from the surface of the multiple leads arranged around the pellet,
Since it is possible to reliably prevent the occurrence of a short circuit accident between the heat sink to which the pellet is bonded and each lead, the quality and reliability of the semiconductor device can be improved.

(6) By exposing a portion of the heat sink so as to slightly protrude from one end surface of the resin-sealed package, it is possible to prevent the sealing resin from adhering to the one end surface of the package as resin burrs, and , it is possible to improve the attachability of the radiation fin to the heat sink and the adhesion of the heat sink to the substrate, etc.

By the way, as shown in FIG. 11, in an IC equipped with a resin-sealed package with a built-in heat sink, the heat sink 11' is attached to the back surface of the inner part 9a group of the leads 9 inside the resin-sealed package 24'. A conceivable configuration is one in which the two are fixedly joined via an insulating layer 15' and an adhesive layer 16'. However, an IC with a built-in heat sink in which a heat sink is bonded to the lead group surface via an insulating layer has the following problems.

(1) The heat sink bonded to the back of the leads via an insulating layer increases the capacitance between the leads.
Furthermore, since the insulation resistance is lowered, the electrical characteristics are lowered, making it unsuitable for semiconductor devices that handle high frequency signals.

(2) Since the IIIA edge layer and the adhesive layer are completely traversal inside the resin-sealed package, and
Moisture resistance is reduced because the ions in the adhesive layer are near the pellets.

However, in this embodiment, the resin-sealed package 24
Since the heat sink 11 is electrically completely separated from the inner portion 9b of the lead 9 inside, the occurrence of such a problem can be avoided.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, when punching and forming a heat sink - 12th
As shown in the figure, by arranging the heat sinks in a zigzag pattern and configuring them in multiple units using outer frames, ease of handling can be improved.

The shape of the joint portion of the lead frame for electrical connection with the heat sink may be formed so as to protrude diagonally, as shown in FIG. 13.

In this case, one cut end of the joint is exposed at each of the four corners of the resin-sealed package.

The joints between the lead frame and the heat sink are not limited to all four corners of the resin-sealed package;
Just place it at the location.

The means for connecting the heat sink and the lead frame for electrical connection is not limited to a fastening structure using rivets, but may also be a bonding structure using an adhesive, a welding structure using a solder material, etc. In these cases, The binding hole can be omitted.

The heat sink is not limited to being configured to slightly protrude from the resin-sealed package, but may be configured to be substantially flush with one end surface of the resin-sealed package (so-called flush).

The shape, size, structure, etc. of the heat sink corresponds to various conditions such as the required heat dissipation performance, mounting form (for example, whether or not to use holding tools or fastening bolts), pellet performance, size, shape, structure, etc. It is desirable to select a heat dissipation fin, a bolt insertion hole, a female thread, etc. as necessary.

Further, the material for forming the heat sink is not limited to copper-based materials, but other metal materials with good thermal conductivity such as aluminum-based materials can also be used. In particular, it is desirable to use a material such as silicon carbide (SiC) that has excellent thermal conductivity and has a coefficient of thermal expansion approximately equal to that of silicon, which is the material of the pellet.

Pounding the pellet onto the heat sink may be performed before the heat sink is bonded to the lead frame.

In the above description, the invention made by the present inventor was mainly applied to an IC equipped with a surface-mounted resin-sealed package, which is the field of application in which the invention was made, but the invention is not limited thereto. It can be applied to resin-sealed power transistors and other electronic devices in general.

In particular, it is small, lightweight, has a large number of bins, is inexpensive, and can be used in semiconductor devices that require high heat dissipation performance to obtain excellent effects.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

By attaching a heat sink to the back side of the pellet,
Since the heat of the pellet can be directly conducted to the heat sink, the heat dissipation performance can be improved even in ICs with small resin-sealed packages, which require high density and high-speed performance [ It is also possible to achieve low thermal resistance in C and the like. As a result, costs can be significantly reduced by implementing resin-sealed packaging for this type of IC and the like.

[Brief explanation of drawings]

Figures 1 (a) and (b) are a front cross-sectional view and a cross-sectional end view along a diagonal line showing a resin-sealed MSP-IC that is an embodiment of the present invention, and Figures 2 to 8 are manufacturing methods thereof. It explains
Fig. 2 is a partially omitted plan view showing the multi-lead frame, Fig. 3 is a perspective view showing the heat sink, Fig. 4 is an enlarged partial perspective view showing the process of joining the heat sink to the lead frame, and Fig. 5 is the pellet. and an enlarged partial plan view after wire bonding; FIG. 6 is a sectional view taken along line VI-VI in FIG. 5; FIG. 7 is a partial longitudinal sectional view showing the resin-sealed package molding operation; FIG. 9 is a partial bottom view showing the package after molding, FIG. 9 is a perspective view showing the mounted state of the MSP-IC, and FIG. 10 is a partially cutaway front view. FIG. 11 is a partial front sectional view showing another IC for explaining its operation. FIG. 12 is a partially omitted plan view showing an example of manufacturing a heat sink, and FIG. 13 is a partially omitted plan view showing a modification of the coupling structure between the heat sink and the lead frame. 1... Multiple lead frame, 2... Honorable lead frame, 3... Outer frame, 4... Sexigon frame, 5...
Dam hanging member, 6... Dam member, 6a... Dam, 7
...Heat sink coupling member, 8...Vacancy, 9...
Electrical connection lead, 11... heat sink, 12.
... Annular groove, 13 ... Lead frame coupling piece, 14
... Rivet, 20 ... Multi-lead frame polymer, 21 ... Pellet, 22 ... Ponding layer, 2
3... Bonding wire, 24... Resin sealing package, 25... MSP/IC (semiconductor device!), 26
...Printed wiring board, 27...Land pad, 3
0... Transfer molding device, 31... Upper mold, 32
...lower mold, 33...cavity 34...pot,
35...Plunger, 36...Cal, 37...Runner, 38...Gate, 39...Recess, 40...
resin.

Claims (1)

[Scope of Claims] 1. A semiconductor device in which a plurality of leads electrically connected to a semiconductor pellet protrude from four sides of a resin-sealed package having a substantially rectangular planar shape. , a heat sink is embedded inside the resin-sealed package, the semiconductor pellet is bonded to the heat sink, and the heat sink is bonded to at least two points used for connection with the lead frame during assembly. A semiconductor device characterized in that coupling portions are respectively disposed at corner portions of the resin-sealed package. 2. The semiconductor device according to claim 1, wherein the heat sink is configured to be spaced apart from a plane of the lead group. 3. The semiconductor device according to claim 1, wherein the heat sink is implanted in the resin-sealed package with the heat sink slightly protruding from one end surface.