JP2794616B2 - Semiconductor hybrid integrated circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor hybrid integrated circuit including a semiconductor optical device, and more particularly to a semiconductor hybrid integrated circuit in which a semiconductor optical device and electronic components constituting peripheral circuits are combined.

[0002]

2. Description of the Related Art A conventional semiconductor hybrid integrated circuit of this type has a structure as shown in FIG. In FIG. 2, the printed wiring board 20 is composed of a substrate 27, a conductor layer 23 on which a predetermined circuit is formed, and an insulating layer 26, and the semiconductor optical device 2 die-bonded on the conductor layer 23 on one surface.
1 is electrically connected to the conductor layer 23 by a bonding wire 22. The semiconductor optical element 21 is made of a transparent resin 2.
4 is sealed in the range limited by the frame 25.

On the other hand, an electronic component (hereinafter referred to as a peripheral circuit component) 28 constituting a peripheral circuit of the semiconductor optical device 21 is attached to the conductor layer 23 on a surface opposite to a surface on which the semiconductor optical device 21 is mounted. 29, it is electrically connected to the conductor layer 23.

[0004]

In the prior art as described above, the linear expansion coefficient of a semiconductor optical device, which is generally a semiconductor such as silicon or a compound semiconductor such as gallium arsenide, and a transparent sealing resin made of an epoxy resin or the like. It is well known that these differ greatly. This is because, when the semiconductor element is an optical element, it is necessary to ensure the transparency of the sealing resin, and it is difficult to adjust the linear expansion coefficient of the sealing resin by adding a filler or the like. Therefore, when the resin-sealed semiconductor optical device is exposed to a high temperature, a large thermal stress occurs between the semiconductor optical device having a small linear expansion coefficient and the transparent resin having a large linear expansion coefficient.

On the other hand, as a method for automatically mounting electronic components that are becoming smaller and smaller, a solder reflow method is generally employed. In this solder reflow method, cream solder is applied in advance to a portion of the conductor layer of the printed wiring board on which the electronic component is to be mounted, the electronic component is placed in a predetermined location, and then heated in an infrared furnace or the like to melt the solder. In this case, the temperature is increased in areas other than the soldered area.

Therefore, if the peripheral circuit components are mounted by the solder reflow method after the semiconductor optical element is mounted, cracks are generated in the sealing resin due to the thermal stress accompanying the heating during the melting of the solder.

Further, when the semiconductor optical device is to be bonded after the peripheral circuit components are mounted, there is a problem that the solder on the peripheral circuit components is melted due to heating during die bonding. In addition, there is another inconvenience that it is difficult to secure parallelism and the like during bonding in a printed wiring board on which peripheral circuit components are mounted first.

For this reason, in a semiconductor hybrid integrated circuit having a structure as shown in FIG. 2, automatic mounting of peripheral circuit components by the solder reflow method cannot be performed, and individual peripheral circuit components are locally heated. Therefore, there has been a problem that the mounting cost becomes very large because of the necessity of soldering.

Conventionally, to solve this mounting problem, a printed wiring board on which peripheral circuit components are mounted is provided separately from a printed wiring board on which semiconductor optical elements are mounted, and the peripheral circuit components are automatically mounted by a solder reflow method. After mounting, a method has been adopted in which a printed wiring board on which peripheral circuit components are mounted and a printed wiring board on which a semiconductor optical element is mounted are connected by lead wires.

However, according to this method, there is an inconvenience that the wiring length between the semiconductor optical device and the peripheral circuit component becomes long. It is well known that the longer the wiring length, the more susceptible it is to external noise. Especially,
When the semiconductor optical element is a light receiving element such as a photodiode,
In many cases, the peripheral circuit of the light receiving element has a high impedance, and is more susceptible to the influence of external noise, which causes a problem of deteriorating high frequency characteristics.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a semiconductor hybrid integrated circuit which has a low mounting cost, is hardly affected by external noise, and has excellent high frequency characteristics. It is.

[0012]

In order to solve the above problems, according to the present invention, a peripheral circuit component is mounted separately from a first printed wiring board mounting a semiconductor optical element sealed with a transparent resin. A second printed wiring board is provided, and at least a part of the first printed wiring board and the second printed wiring board are joined.

Specifically, at least a part of the surface of the first printed wiring board on which the semiconductor optical element is not mounted and the electronic component of the second printed wiring board are not mounted. At least part of the side faces are joined,
Conductive circuits formed on the first and second printed wiring boards are electrically connected.

[0014]

As described above, according to the present invention, the semiconductor optical element and the peripheral circuit component are mounted on separate printed wiring boards. For this reason, it becomes possible to automatically mount the peripheral circuit components by a solder reflow method or the like without causing thermal stress to the semiconductor optical element sealed with the transparent resin, and the disadvantage that the mounting cost is large is solved.

According to the present invention, a first printed wiring board on which a semiconductor optical element is mounted and a second printed circuit board on which a peripheral circuit component is mounted are provided.
Since the printed wiring board is directly joined, the wiring length between the semiconductor optical element and the peripheral circuit component is shortened. This solves the problem that the wiring inductance and the parasitic capacitance are reduced, are easily affected by external noise, and the high-frequency characteristics are degraded.

The joining of the first printed wiring board and the second printed wiring board can be easily realized by a generally well-known method of forming an adhesive layer such as an adhesive or a double-sided tape.

[0017]

FIG. 1 is a sectional view showing a configuration of a semiconductor hybrid integrated circuit according to an embodiment of the present invention. In the figure, a first printed wiring board 1 includes a substrate 17, a conductor layer 13 formed into a circuit in a predetermined shape, and an insulating layer 16, and the conductor layers 13 on the front and back are formed with through holes or the like (not shown). Z)
Is conducted.

The semiconductor optical element 11 has a conductor layer 1 on one side.
3 and is electrically connected to the conductor layer 13 by a bonding wire 12.
The semiconductor optical element 11 is sealed in a range limited by a frame 15 with a transparent resin 14.

On the other hand, the second printed wiring board 2 is
7, the conductor layers 13, 13a and the insulating layer 16. The conductor layer 13 on one side (mounting surface side) is formed into a circuit in a predetermined shape, and the conductor layer 13a on the other side (joining surface side) is formed.
Are provided over a wide range, and function as a shield layer when connected to a ground potential. These conductor layers 13 and 13a are covered with an insulating layer 16 except for portions necessary for soldering or the like. Further, an opening 4 is provided at a predetermined position of the second printed wiring board 2 for establishing electrical continuity with the first printed wiring board 1.

The peripheral circuit components 18 of the semiconductor optical element 11 mounted on the first printed wiring board are mounted on the conductor layer 13 on one side of the second printed wiring board by a method such as a solder reflow method. And is electrically connected to the conductor layer 13 via the solder 19.

The first printed wiring board 1 and the second printed wiring board 2 are bonded together by an adhesive layer 3 on the side on which the semiconductor optical element 11 and the peripheral circuit component 18 are not mounted. , First and second printed wiring boards 1 and 2
The conductive layer 13 is electrically connected by solder 19 through the opening 4 of the second printed wiring board 2 using a so-called solder bridge method.

Next, an example of a method for manufacturing the semiconductor hybrid integrated circuit of FIG. 1 will be described. First, the circuit formation of the conductor layer 13 of the first and second printed wiring boards is performed by a known subtractive method or the like. Then, if necessary,
A desired portion of the conductor layer 13 is covered with the insulating layer 16. The insulating layer 16 is not always necessary, and need not be provided if there is no problem in the soldering process or the insulation reliability. Further, in the example of FIG. 1, the first and second printed wiring boards 1 and 2 use a two-layer printed wiring board, but the printed wiring board used in the present invention is a multilayer printed wiring board having three or more layers. Needless to say, a single-sided printed wiring board may be used.

After the first and second printed wiring boards 1 and 2 are manufactured, the first printed wiring board 1
1 is mounted and resin sealing is performed. In this embodiment, the semiconductor optical element is mounted by the wire bonding method, but may be mounted by other methods. For example, TA
It is also conceivable to mount a light receiving element by the method B and receive optical information by backside irradiation.

On the other hand, peripheral circuit components 18 are mounted on the second printed wiring board 2 by a solder reflow method or the like. In the present embodiment, the peripheral circuit component 18 is a surface-mounted component, but it goes without saying that an insertion-type component may be used, and the mounting method is not particularly limited.
As a soldering method other than the solder reflow method, for example, a wave soldering method (contacting a printed wiring board with a solder jet wave and soldering mainly inserted components), a deep soldering method (stilling a printed wiring board stationary). In this invention, the printed wiring board on which the peripheral circuit components are mounted and the printed wiring board on which the semiconductor optical element is mounted are separately provided. Therefore, a desired mounting method can be selected without being limited by the heat resistance of the semiconductor optical element 11 and the transparent resin 14.

After mounting the semiconductor optical element 11 and the peripheral circuit components, respectively, the first and second printed wiring boards 1 and 2 are mounted.
Are bonded together by the adhesive layer 3. In the example of FIG. 1, the entire non-mounting surface is joined, but it is not always necessary to join the entire surface as long as the portions where conductive connection between the two printed wiring boards 1 and 2 are joined.

In FIG. 1, the first and second printed wiring boards 1 and 2 have the same dimensions.
It is also possible to reduce the size of the printed wiring board and mount an insertion-type component in a region other than the joint portion of the second printed wiring board 2. In some cases, the semiconductor optical device 11,
A configuration may be adopted in which matching is performed on the mounting surface side of the peripheral circuit component 18.

After joining the first and second printed wiring boards 1 and 2, the conductor layer 13 on the peripheral circuit component mounting surface side of the second printed wiring board and the joining layer side of the first printed wiring board 1 The conductor layer 13 is connected by the solder bridge method via the opening 4 of the second printed wiring board to complete the semiconductor hybrid integrated circuit as shown in FIG. The method of electrically connecting the first and second printed wiring boards 1 and 2 is not particularly limited, and electrical connection may be made using a conductive paste or the like.
In some cases, the first and second printed wiring boards 1 and 2 may be connected to other external circuits instead of being directly connected.

The structure of the present invention is, for example, a light receiving / imaging element such as a photodiode or an image sensor, and an LED.
In addition to a light emitting element such as, for example, a peripheral circuit such as a liquid crystal is required and can be applied to an element which is weak to heat.

[0029]

As described above, according to the present invention, a printed wiring board on which a semiconductor optical element sealed with a transparent resin is mounted and a printed wiring board on which peripheral circuit components are mounted are separately provided. , The peripheral circuit components can be mounted by a desired method without being limited by the heat resistance of the semiconductor optical element and the transparent resin, and the semiconductor optical element The length of the wiring for electrically connecting the semiconductor device and the peripheral circuit component can be reduced.

Therefore, in the hybrid integrated circuit of the present invention, the mounting cost can be reduced by automatically mounting the peripheral circuit components by the solder reflow method or the like, and the effect of the external noise can be prevented, and the excellent high frequency Characteristics can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a semiconductor hybrid integrated circuit according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional semiconductor hybrid integrated circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st printed wiring board 2 2nd printed wiring board 3 Adhesive layer 11 Semiconductor optical element 12 Bonding wire 13, 13a Conductive layer 14 Transparent resin 15 Frame 16 Insulating layer 17 Substrate 18 Peripheral circuit parts 19 Solder

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisao Takahashi 1-6-3 Nishioi, Shinagawa-ku, Tokyo Nikon Oi Works Co., Ltd. (56) References Jikai Sho 61-66959 (JP, U) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) H01L 25/00

Claims (3)

(57) [Claims] 1. A semiconductor optical device sealed with a transparent resin,
An electronic component forming a peripheral circuit of the semiconductor optical element; and a first printed wiring board mounting the semiconductor optical element in a semiconductor hybrid integrated circuit having a printed wiring board mounting the semiconductor optical element and the electronic component. A second printed wiring board on which the electronic component is mounted, wherein at least a part of the first printed wiring board and at least a part of the second printed wiring board are joined. Hybrid integrated circuit. 2. The semiconductor device according to claim 1, wherein the first printed wiring board has at least a part of a surface on which the semiconductor optical element is not mounted.
2. The semiconductor hybrid integrated circuit according to claim 1, wherein at least a part of a surface of said second printed wiring board on which said electronic component is not mounted is joined. 3. The conductive circuit formed on the first printed wiring board and the conductive circuit formed on the second printed wiring board are electrically connected to each other.
A semiconductor hybrid integrated circuit as described in the above.