JPH11163391A - Optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical semiconductor device which is assembled by arranging a light-emitting element and a light-receiving element facing each other, thereby making molding process easier and permitting mass production at a lower cost. SOLUTION: A device comprises an insulating material 1 which is optically transparent at least in part, conductive members 2a, 2b as leader electrodes respectively adhered to both the surfaces, a light-emitting element 3 electrically connected to a conducting member 2a adhered to one surface of the insulating material 1, a light-receiving element 4 connected electrically to a conductive member 2b adhered to another surface of the insulating material 1, and a package 6 for protecting the light-emitting element 3 and the light-receiving element 4. The light-emitting element 3 and the light-receiving element 4 are arranged to face each other through an optically transparent portion of the insulating material 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor device having a non-contact contact such as a photocoupler for converting an optical signal into an electric signal.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional optical semiconductor device of this type using a photocoupler as an example. In the figure, reference numerals 2g and 2h denote lead frames, and the light emitting element 3 and the light receiving element 4 are die-bonded to each die island, and the respective inner leads and the electrodes 3a and 4a of the light emitting element 3 and the light receiving element 4 are gold wires. Etc. are electrically connected by wires 5c and 5d.

As the light emitting element 3, an LED is generally used, and as the light receiving element 4, a photodiode or a phototransistor is generally used. The package 6 is made of a resin or ceramic provided for protecting the light emitting element 3 and the light receiving element 4 from disturbance light and corrosive atmosphere. A resin package formed by transfer molding in consideration of mass productivity is generally used. Have been.

The illustrated photocoupler is assembled by arranging the light emitting surface and the light receiving surface of the light emitting element 3 and the light receiving element 4 to face each other so that their optical axes are aligned, and enclosing them in a package 6. With such a configuration, for example, in the case where the light receiving element 4 is a photodiode, a current is applied to the wire 5c to cause the light emitting element 3 to emit light.
An electric signal corresponding to the light emission amount of the light emitting element 3 is generated on the side of the light receiving element 4 to which the bias is applied through the wire 5b.
Through the external lead of the lead frame 2h.

[0005]

However, it is difficult to assemble and mold the light-emitting element and the light-receiving element with the light-emitting surface and the light-receiving surface of the light-emitting element and the light-receiving element accurately facing each other with the above-described structure, and thus require many man-hours. However, there was a problem in mass production at low cost.

For example, a light emitting element and a light receiving element each having two lead frames mounted thereon are arranged so as to face each other,
During molding, it is necessary to maintain that state, but at this time, contact between the wire and the element or between the wires must be avoided, and a predetermined gap is required. Further, in order to align the optical axes, the positions of the light emitting element and the light receiving element must be adjusted with a predetermined accuracy. That is, the handling and loading for that purpose become complicated, and this is an adverse effect of automation.

[0007]

In order to solve the above problems, an optical semiconductor device according to the present invention comprises an optically transparent insulating material having at least a part thereof, and a lead electrode which is respectively attached to both surfaces of the insulating material. A conductive material, a light emitting element electrically connected to the conductive material attached to one surface of the insulating material, and a light emitting element electrically connected to the conductive material attached to the other surface of the insulating material. A light-receiving element connected thereto, and a package for protecting the light-emitting element and the light-receiving element, wherein the light-emitting element and the light-receiving element are opposed to each other via an optically transparent portion of the insulating material. It is characterized by.

The optically transparent portion of the insulating material may be a through hole.

Further, the conductive material may be a patterned thin film.

Further, the conductive material may be a lead frame.

[0011] In these optical semiconductor devices, the light emitting element and the light receiving element may each be face-down bonded to the conductive material. At this time, the light emitting element and the light receiving element are suitable as a flip chip.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. However, in a plurality of drawings, the same or corresponding components are denoted by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a view showing an embodiment of an optical semiconductor device according to the present invention. In FIG. 1, reference numeral 1 denotes a transparent substrate such as a transparent resin or a glass plate, and 2a and 2b cover copper foil on the transparent substrate 1. 3a and 4a are bump electrodes formed on the main surface (light receiving / emitting surface) of the light emitting element 3 and the light receiving element 4, respectively, and 3b and 4b are back electrodes of the light emitting element 3 and the light receiving element 4 respectively. , 5a and 5b are back electrodes 3 respectively.
b, 4b and wires such as gold wires connecting the thin films 2a, 2b.

In order to configure the present embodiment, for example, solder bumps are formed on the electrodes on the main surfaces of the light emitting element 3 and the light receiving element 4, and solder printing is performed on the contact portions of the copper foil patterns 2a and 2b on the transparent substrate 1. After mounting the light emitting element 3 or the light receiving element 4, the bumps are melted by a reflow furnace or laser, and face down bonding is performed.

As a result, as shown, the light emitting element 3 and the light receiving element 4 are arranged to face each other with the optically transparent transparent substrate 1 interposed therebetween, and the positions of the light emitting element 3 and the light receiving element 4 are thin films 2a and 2b.
Is almost determined only by the pattern accuracy, and the difficulty in alignment is eliminated. The wires 5a and 5b are bonded for grounding.

FIG. 2 is a view showing another embodiment of the optical semiconductor device according to the present invention. The difference from FIG. 1 is that a through hole 11a is partially provided as an optically transparent insulating material. An adhesive plate 11 made of a polyurethane * 1 base material is used, and lead frames 2c and 2d are used as conductive materials to be attached thereto. However, a die island is not required for the lead frames 2c and 2d, and the lead island
It has become.

In order to configure the present embodiment, the light emitting element 3
The light receiving element 4 and the light receiving element 4 are mounted on the lead frames 2c and 2d in different steps by face-down bonding, and are bonded and integrated via an adhesive plate 11. At this time, the light emitting element 3 and the light receiving element 4 are arranged so as to face each other such that the through hole 11a forms an optical path.

Also in the present embodiment, the semi-finished product can be integrated before the molding process and can be handled in the same form as one lead frame, so that the complexity associated with the subsequent positioning is eliminated. The alignment between the light emitting element 3 and the light receiving element 4 can be easily performed by using the same lead frames 2c and 2d.

FIG. 3 is a diagram showing still another embodiment of the optical semiconductor device of the present invention, and shows a modification of the optical semiconductor device shown in FIG. The feature of this embodiment is that a conventional lead frame 2g is used for one of the conductive materials, and the light emitting element 3 is mounted thereon in the conventional process.

FIG. 4 is a view showing still another embodiment of the optical semiconductor device of the present invention.
Shows a case where both are constituted by flip chips. As described above, if the ground electrode can be formed on the main surface in the planar structure, all the electrodes are formed of the lead frame 2e with solder bumps.
Since it can be connected to 2f, a simple structure as shown in the figure is also possible. In this case, the back electrodes 3b, 4b are formed as reflecting mirrors for preventing a reduction in efficiency due to light leakage, and the lead frames 2e, 2f are formed in a die island portion like the lead frames 2c, 2d in FIG. Is missing.

Although the embodiment has been described above, the present invention is not limited to this, and various modifications can be made. For example,
In addition to the insulating material described in the above embodiment, a flexible insulating film such as polyimide may be used, and several insulating films may be bonded with an adhesive. Further, the insulating material may be a material obtained by curing an adhesive such as a phenol resin in a paste state.

[0022]

As described above, since the light-emitting element and the light-receiving element are mounted together with a simple configuration and an integrated semi-finished product can be formed, the assembly is greatly simplified, and the automation can be easily performed. It has the advantage that optical semiconductor devices can be produced inexpensively and in large quantities.

By making the optically transparent portion of the insulating material a transparent hole, an opaque material can be used, and the range of use of the material can be expanded.

Further, by making the conductive material a patterned thin film, it is possible to eliminate the difficulty of securing the alignment accuracy in assembly.

Further, by using a lead frame as the conductive material, it can be easily realized within the range of conventional mass production techniques.

Further, by adopting a structure in which the light emitting element and the light receiving element are respectively face-down bonded to the conductive material, the distance between the light emitting element and the light receiving element can be shortened irrespective of the height of the wire. In this case, the effect of the attenuation characteristics due to the resin interposed between the light emitting element and the light receiving element can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing another embodiment of the optical semiconductor device according to the present invention.

FIG. 3 is a diagram showing still another embodiment of the optical semiconductor device according to the present invention.

FIG. 4 is a diagram showing still another embodiment of the optical semiconductor device according to the present invention.

FIG. 5 is a diagram showing a conventional optical semiconductor device.

[Explanation of symbols]

 1: transparent substrate 2a, 2b: thin film 2c to 2h: lead frame 3: light emitting element 4: light receiving element 5a to 5d: wire 6: package 11: adhesive plate 11a: through hole

Claims (5)

[Claims] 1. An insulating material that is at least partially optically transparent, a conductive material that is respectively attached to both surfaces of the insulating material and serves as a lead electrode, and the conductive material that is attached to one surface of the insulating material. A light emitting element electrically connected to the material, a light receiving element electrically connected to the conductive material attached to the other surface of the insulating material, and a package for protecting the light emitting element and the light receiving element. Wherein the light emitting surface of the light emitting element and the light receiving surface of the light receiving element are opposed to each other via an optically transparent portion of the insulating material. 2. The optical semiconductor device according to claim 1, wherein the optically transparent portion of the insulating material is a through hole. 3. The optical semiconductor device according to claim 1, wherein the conductive material is a patterned thin film. 4. The optical semiconductor device according to claim 1, wherein the conductive material is a lead frame. 5. The optical semiconductor device according to claim 1, wherein the light emitting element and the light receiving element are face-down bonded to the conductive material, respectively.