JPH02188946A - Resin-sealed semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To supply a device in which various kinds of circuit constitutions have been compounded, which does not require an external insulation treatment and which is small-sized and can be handled simply and easily by a method wherein a heat sink on which a semiconductor chip has been mounted is sealed with a first resin, a circuit component is then mounted on a lead and this whole assembly is sealed with a second resin. CONSTITUTION:A heat sink 22 on which a semiconductor chip 21 has been mounted is sealed in a first resin-molded part 27; a circuit component 25 is mounted on a lead 24b which is interlinked with the first resin-molded part 27; said first resin-molded part 27 and said circuit component 25 are sealed with a second resinmolded part 29. For example, a heat sink 22 on which a semiconductor chip 21 has been mounted is sealed with a first resin in a state that strips 23 extended from the heat sink 22 and leads 24a are gripped by using a first metal mold and that the heat sink 22 is levitated in a space inside the metal mold. Then, the strips 23 and one part of the leads 24a are cut; a circuit component 25 is mounted on a remaining lead 24b; and an electrical connection such as a soldering operation or the like is executed. After that, a first resin-molded part 27 and external leads 24c are gripped by using a second molding metal mold and are positioned; and a second resin-molded part 29 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a resin-sealed semiconductor device in which a heat sink is insulated and sealed.

<Summary of the Invention> The present invention involves sealing a heat sink on which a semiconductor chip is mounted with a first resin, mounting and connecting circuit components such as resistors and capacitors on the leads, and sealing the entire thing with a second resin. By doing so, it is possible to provide a resin-sealed semiconductor device for electric power in which conventional external components are integrated.

<Prior Art> In recent years, in response to the demand for high reliability and long life of device control relays, non-contact relays, that is, solid state relays that are resin-sealed semiconductor devices have been developed. A general solid state relay is constructed of a circuit as illustrated in FIG.

In this example, the solid state relay is composed of an optical coupling section 3 consisting of a phototriac 2 in which light emitting diodes 1 and 7 otothyristors are connected in antiparallel, and a triac 4 driven by the output of the optical coupling section 3. When a signal is applied to the light emitting diode 1 through the limit resistor RL, the phototriac 2 turns on,
By supplying current to the gate of the triac 4 to turn on the triac 4, switching of the upper right circuit is performed.

Solid state relays that perform such operations have conventionally been formed by incorporating individual components such as optical coupling elements and triacs and lead terminals into a printed circuit board and sealing the board with resin. In response to this, the present applicant has proposed a resin-sealed solid state relay constructed only of semiconductor chips (for example, Japanese Patent Application No. 153617/1982). This structure is shown in FIG.

In FIG. 9, the solid state relay has a heat sink 5
On the top, an optical coupling section 3 consisting of a phototriac 2 and a light emitting diode 1 optically coupled through a transparent insulating layer and a triac 4 are mounted. has been realized.

The first example of incorporating this solid state relay into equipment is
Shown in Figure 0. The solid state relay is fixed to the equipment heat sink 7 with screws 8, but the heat sink 5 is connected to the power supply line of the load, and an insulating plate 9 is required to electrically insulate it from the equipment heat sink 7. .

In order to cope with this problem, various structures of semiconductor devices have been proposed in which a heat sink is insulated and sealed with molded resin lO as shown in FIG. ).

In FIG. 11, the strip projections 11 are strip cold pieces that are held between upper and lower molds in order to properly position the heat dissipation plate 5 within the mold.

<Problems to be Solved by the Invention> When the solid state relay described above is actually used, in order to absorb switching noise and prevent malfunction, the snubber circuit 6 consisting of a resistor and a capacitor is connected externally as shown in FIG. It is often used in addition to. This snubber circuit generally uses a lead resistor and a film capacitor, so even if the solid state relay body is made smaller, the size of the external circuit is large, which hinders the miniaturization of the entire system and the realization of high-density packaging. Compact integration including external circuits was desired.

In addition, insulation of the heat sink 5 is often required, and it is possible to adopt the structure shown in FIG. Since the potential difference between the device and the main body is several hundred ports or more, some type of insulation treatment is required.

As a countermeasure against this, it is possible to coat the strip projections 11 with resin (Japanese Patent Application Laid-Open No. 16451/1983), or to re-apply the strip projections 11 with resin.
It has been proposed to mold and seal (Japanese Unexamined Patent Publication No. 59-215752). However, these methods add unnecessary steps to the original product configuration, which tends to increase product costs, and it is difficult to develop an insulated resin-sealed semiconductor device in conjunction with the integration of the external circuit described above. It was wanted.

Means for Solving the Problems> In the present invention, in order to solve the above problems, a resin-sealed semiconductor device is constructed as shown in FIGS. 1 to 4.

That is, in FIGS. 1 to 4, the heat sink 22 on which the two semiconductor chips are mounted is held between the strips 23 and leads 24a extending from the heat sink 22 by a first mold, and the heat sink 22 is placed in the mold. It is sealed with the first resin while floating in the space inside.

After that, part of the strip 23 and the lead 24a is cut,
The circuit components 25 are mounted on the remaining leads 24b, and electrical connections such as soldering are made. After this, the second molding die 2
6, the first resin molded part 27 and the external lead 24c are sandwiched and positioned, and the fourth resin molded part 27, the lead 24b on which the circuit component is mounted, and the first resin molded part 27 are exposed by the resin of vj2. After forming the second resin molded part 29 by molding and sealing the striped protrusions 28, the external leads 2
The common connection strip 30 connected to 4c is cut.

<Function> By adopting such a means, after the first resin molding, the leads 24a are fixed to the fourth resin molded part 27, so the leads can be cut, and the semiconductor chip 2
1 is sealed with resin, soldering of the circuit component 25 onto the lead 24b can be performed extremely easily. Further, by performing a second resin molding, it is possible to seal the circuit component 25 and insulate the remaining strip projections 28 in the same process. At this time, since the second molding die 26 is positioned within the mold by holding the first resin molded part 27 between them, highly accurate molding is possible.

<Example> Next, a more detailed example will be described based on the drawings.

Although the description will be made with reference to solid state relays, the present invention is not limited to this, and may be applied to resin-sealed power relays such as inverter modules, switching power supply regulators, and DC relays having similar configurations. Of course, the present invention can be applied to a semiconductor device, that is, a semiconductor device in which a semiconductor chip and circuit components are sealed in the same package.

In order to form the solid state relay of FIG. 1, a lead frame as shown in FIG. 2 is first used. The lead frame includes a heat sink 22 and strips 23 extending from the heat sink 22. Leads 24 (a, CL common connection strips 30, etc.) are soldered and attached to the heat sink 22, and then wire-bonded with thin metal wires 31 such as aluminum. 2. First resin sealing is performed in the shape indicated by dotted lines in Figure 2. During molding, the strips 23 and leads 24a are formed using the first mold.

The external lead 24c and the like are held and positioned. Although molding is possible without the strips 23, the positional accuracy of the heat sink 22 will be poor.

After the first resin molding, the strips 23 are cut to form strip protrusions 28 to form the lead frame shape shown in FIG.

Further, at the same time as this step or separately, the leads 24a are partially cut and punched to form the remaining leads 24b. This step is performed to prevent unnecessary active portions other than the external leads 24c from being exposed in the finished product and to form relay terminals for wiring within the package. Strip 23 and lead 2
After cutting 4a, circuit components 25 (a+b+c) are mounted.

In this example, the circuit component 25 is an optical coupling element 25a.

It is composed of a chip resistor 25b and a chip capacitor 25c for a snubber circuit.

The circuit component 25 is soldered using a normal soldering process,
After soldering, remove the remaining solder flux.
9. At this time, the semiconductor chip 21 is
Since it is sealed by the resin molded part 27, no special consideration is required.

After solvent cleaning, a second
Seal with resin. This is done using a second mold 26 (a, b) as shown in FIG. That is, the upper mold 26a and the lower mold 26b form the first resin molding part 2.
7 and external leads 24c and common connection strips 30a, 80
The remaining glue 24b and circuit components 25.b are held in place. A second resin molded portion 29 is formed by replacing the first resin molded portion 27 and the strip projection 28 with a second resin. Thereafter, the common connection strip 30a connecting the external lead 24c
and 30b are cut, the external lead 24c is separated, and the external lead 24c is further subjected to VC solder plating.

Through the above steps, a solid state relay in which the semiconductor chip 21 and the circuit component 25 are integrally insulated and sealed is completed.

Although this embodiment used a lead frame having the shape shown in FIG. 2, in order to reinforce the leads 24a and prevent resin from flowing into the leads 24a during the first resin molding, a fifth
As shown in the figure, it is also possible to add a third common connection strip 80c and cut and remove it after the first resin molding. Moreover, after the first resin molding, the circuit component 2 can be removed without cutting the leads 24a.
It is also possible to mount the lead 24a and then partially cut the lead 24a. Additionally, a limit resistor on the input side can also be installed.

Next, other embodiments will be described. In the explanation so far, the optical coupling element 25a, which is an individual component, is mounted as one component constituting the circuit component 25, but the optical coupling element is separately sealed in the same resin molding part as the semiconductor chip 21. It can be formed by Examples thereof are shown in FIGS. 6 and 7.

Here, the phototriac chip 31 is mounted on the heat dissipation plate 22 via an insulating plate 32 such as a polyimide sheet.
In the figure, the light emitting diode chip 33 is connected to the lead 24d.
After wire bonding with a gold wire 35, an optical path is formed with a transparent silicone resin 36. In the case of FIG. 7, the light emitting diode 33 is a phototriac 31
The light-emitting diode 33 is mounted on a transparent insulating layer 34 which is laminated thereon and has an electrode lead-out portion from the light-emitting diode 33 for optical coupling. The first resin molded part 27 that seals these optical coupling parts may be made of a resin mixed with a white pigment such as titanium oxide TiO2 or calcium carbonate CaCO3, which has high light reflectivity, in order to improve photoelectric conversion efficiency. desirable.

<Effects of the Invention> As described above, the resin-sealed semiconductor device of the present invention has the following advantages:
A semiconductor chip and circuit components can be easily sealed in the same package, and relay terminals, strip projections, and heat sinks that should not be exposed to the outside can be completely insulated and sealed. As a result, it is possible to supply a small and easy-to-handle device that combines a wide variety of circuit configurations and does not require external insulation treatment.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of a resin-sealed semiconductor device of the present invention, FIGS. 2(a) and (b) are a plan view and a side view showing the state after mounting a semiconductor chip, and FIG. (a) and (b) are a plan view and a side view showing the state in which circuit components are mounted, FIG. 4 is a cross-sectional view of the second resin molding, and FIG.
The figure is a plan view of a lead frame with a different shape in the same example.
6(a) and (b) and FIG. 7(a) and (b) are respectively a plan view and a partial sectional view of other embodiments of the present invention;
Figure 8 is a circuit diagram of a solid state relay, Figure 9 is a plan view showing a conventional solid state relay, Figure 1O is a sectional view showing how the conventional solid state relay is installed in equipment, and Figure 11. 1 is a cross-sectional view showing how a conventional resin-sealed semiconductor device with a heat dissipation plate insulated and sealed is attached to a device. 21... Semiconductor chip, 22... Heat sink, 23...
- Strip, 24a... Lead, 24b... Remaining lead, 25c... External lead, 26 - Second molding die,
27... First resin molded part, 28... Strip projection, 2
9... Second resin molded part, 30... Common connection strip. Agent Patent attorney Takeshi Sugiyama (1 other person) (σ) (b) Figure 2 (G) Figure 3 (b) Figure 5 Figure 8 Figure 1O

Claims (1)

[Scope of Claims] 1. A heat dissipation plate mounted with a semiconductor chip is sealed in a first resin molded part, a circuit component is mounted on a lead connected to the first resin molded part, and A resin-sealed semiconductor device, characterized in that a molded part and the circuit component are sealed by a second resin molded part. 2. A semiconductor chip is mounted on a heat sink, the strips and leads extending from the heat sink are held in a first molding mold, and the heat sink is suspended in the cavity in the mold. After forming the resin molded part, the strip and part of the lead are cut, circuit components are mounted and electrically connected on the remaining leads, and then the first part is molded in a second molding die. The resin molded part and the external lead are held and positioned, the first resin molded part, the circuit component mounting part, and the strip projections from the first resin molded part are sealed, and the second resin molded part is molded. After forming the section,
A method of manufacturing a resin-sealed semiconductor device, comprising cutting a common connection strip connected to an external lead.