JPS5832514B2 - handoutaihikariketsugousoshi - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a semiconductor optical coupling device that obtains optical coupling by combining a light emitting element die and a light receiving element die, and in particular improves optical coupling efficiency and simplifies the assembly process. It is something.

A cross-sectional view of an example of a conventional semiconductor optical coupling device is shown in FIGS. 1 and 2.

FIG. 2 is a sectional view taken in a different direction from FIG. 1.

First, in FIG. 1, 1 is a light emitting element die, and this light emitting element die 1 is an infrared light emitting diode using GaAsP, a visible light emitting diode using GaAsP, GaP materials, etc. Currently commonly used due to its relationship.

Reference numeral 2 denotes a light-receiving element die, and the light-receiving element die 2 may be a CdS, CdSe, Si photodiode, or a transistor, but here, a case of a GaAs infrared light emitting diode and a Si phototransistor will be explained.

Now, the light emitting diode 1 is die-bonded to the lead 4, and the other electrode 9 of the light emitting diode 1 and the lead wire 3 are wire-bonded using the thin metal wire 10 to obtain an electrical connection.

Similarly, for the light receiving element, the phototransistor 2 is die-bonded to the lead 7, and the emitter electrode 11 and the lead 6, and the base electrode 12 and the lead 8 are wire-bonded using thin metal wires 13 and 14 to obtain electrical connections. I have to.

Next, these two types of lead frames 101 and 102 are fixed as shown in FIG. 2, a transparent material 15 is used to cover the space between the light emitting diode 1 and the phototransistor 2, and an opaque material 16 is used to block external light. It is sealed.

For the transparent material 15 and the opaque material 16, inexpensive plastics such as epoxy resin and silicone resin are often used.

When the semiconductor optical coupling device formed in this manner operates, an input signal is applied to the leads 3 and 4, causing the light emitting diode 1 to emit light, and the emitted light passes through the transparent material 15 and is connected to the phototransistor 2. is irradiated to generate photo-induced power, which is extracted as an output signal.

However, in this way, two types of lead frames 101.
When fixing the light emitting diode 1 and phototransistor 2, make sure that the thin metal wire 10°13.14 does not come into contact with each other.
There must be sufficient space between the two.

Therefore, the optical coupling efficiency was poor.

Moreover, the optical coupling efficiency varied due to misalignment of the dies 1 and 2 to be die-bonded and bending of the lead frames 101 and 102.

In addition, two types of lead frames 1 after wire bonding are shown.
01 and 102 were difficult to handle until they were sealed with the transparent material 15, and in addition, the work required to be skilled and careful when injecting the resin of the transparent material 15, resulting in poor workability and yield. was making things worse.

The present invention has been made in view of the above-mentioned conventional drawbacks, and an object thereof is to provide a semiconductor optical coupling device having a structure capable of improving optical coupling efficiency and simplifying work.

Embodiments of the semiconductor optical coupling device of the present invention will be described below with reference to the drawings. FIGS.
First, 17 in FIG. 3a is a conductive plate.

The conductive plate 17 is a metal plate made of Kovar, copper, iron, nickel, etc., and plated with silver or gold.

As conditions for the conductive plate 17, it is necessary to select a material that has good thermal conductivity and has a coefficient of thermal expansion close to that of the light emitting element die 1 and the light receiving element die 2.

Next, the conductive epoxy resin 18 is die-bonded to the side coated with the conductive epoxy resin 18 in alignment with the window 19 of the conductive plate 17 through which light passes, and is fixed by thermosetting.

Note that the electrode 9 on the side from which light is emitted from the light emitting diode 1 (
In FIG. 3b), the conductive plate 17 is provided at the periphery so that the emission of light is not obstructed.

21 is a back electrode of the light emitting diode.

Next, as shown in FIG. 3C, a transparent material 15 is injected into the window 19 through which light passes.

Since this transparent material 15 needs to be insulating and have an adhesive effect, epoxy resin is suitable.

Then, the phototransistor 2 (FIG. 3e) is die-bonded and fixed by thermosetting.

As shown in FIG. 4a (plan view of the light-receiving element die), this phototransistor 2 includes an emitter electrode 11 (see FIGS. 1 and 2), a bonding portion 23 of the base electrode 12 (see FIG. 4b), 24 is positioned in the corner, and
As shown in FIG. 3d, the surface of the parts other than the bonding parts 23 and 24 is insulated with an insulating material 29 such as phosphor glass, and is therefore insulated from the conductive plate 17.

Note that 25 is the collector electrode of the phototransistor.

Next, as shown in FIGS. 3e and 3f (plan view of FIG. 3e), a lead frame 10 that does not require bending is manufactured.
The lead 20 of No. 3 is die-bonded using a conductive epoxy resin 18.

Then, the back electrode 21 of the light emitting diode 1 and the lead 30
, the conductive plate 17 and the lead 31. Also, the emitter electrode 11 of the phototransistor 2. Electrical connection is established by wire-bonding the bonding portions 23 and 24 of the base electrode 12 and the leads 33 and 34 using the thin metal wires 22.

In addition, 26 in the figure is an emitter region, 27 is a base region,
28 is a collector area.

After wire bonding as described above, the opaque material 1 is finally applied.
6 to seal the whole.

In the above embodiments, a phototransistor was used as the light receiving element, but a photodiode or other semiconductor element may also be used.

Furthermore, although the conductive epoxy resin has been described as the conductive adhesive, it goes without saying that a solder material such as Au-8i may also be used.

According to the invention described in detail above, the following effects are achieved.

(1) Since the distance between the light emitting element and the light receiving element is approximately the same as the thickness of the conductive plate, they can be positioned very close together, and the light from the light emitting element reaches the light receiving element without leaking to the outside. Optical coupling efficiency improves.

(2) Since the thickness of the conductive plate is uniform and the structure is not affected by misalignment of the die to be bonded, there is little variation in optical coupling efficiency.

(3) It becomes easier to inject a transparent substance between the light emitting element and the light receiving element.

(4) Wire bonding of the light-emitting element and light-receiving element can be done at the same time, which was previously done separately, which simplifies the assembly process. (5) The lead frame does not require expensive molds for bending. Moreover, since two types of lead frames are replaced with one type, the cost is reduced.

(6) Since the overall work is simplified, workability is improved and yield is improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional semiconductor optical coupling device, FIG. 2 is a cross-sectional view of the same conventional semiconductor coupling device taken in a direction different from that in FIG. 1, and FIGS. FIG. 3f is a plan view of FIG. 3e, and FIG. FIG. 4 is a plan view of the light-receiving element die in the example, and a cross-sectional view of the same light-receiving element die as described above. 1...Light emitting diode die, 2...Phototransistor die, 9...Light emitting diode electrode, 15...Transparent material, 16...・
Opaque substance, 17... Conductive plate, 18...
・Conductive epoxy resin, 20°30~34...
Lead, 21... back electrode of light emitting diode,
22...Thin metal wire, 23, 24...
Bonding portion, 25... Collector electrode of phototransistor, 29... Insulating layer. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A metal conductive plate with a window through which light passes, a conductive material coated on one side of this metal conductive plate, a light emitting element in which one side electrode of a light emitting element die is adhered to this conductive material, and this light emitting element an insulating transparent material injected into the window of the metal conductive plate in a bonded state; a light receiving element having a portion other than the first electrode bonded to the other surface of the metal conductive plate via an insulating substance; A lead frame 5 that does not require bending is die-bonded to the second electrode of the light-receiving element via a conductive resin.An opaque material is used to seal the entire body while the electrodes of the light-emitting element and the light-receiving element are wire-bonded. A semiconductor optical coupling device.