JP2003249710A - Package for housing optical semiconductor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an optical coupling efficiency of an optical semiconductor element to an optical fiber from being deteriorated by largely alleviating a strain generated at a base or a frame due to a heat of the element and to allow a high-frequency signal to be smoothly transmitted when the signal of 40 GHz band is used. <P>SOLUTION: The base 3 made of a metal of a substantially rectangular shape having a placing part 3a of the optical semiconductor element 2 on an upper surface is made of the metal having a larger thermal expansion coefficient at a room temperature to 100°C than that of the frame 5, mounted to surround the part 3a on the upper surface of the base 3. The frame 5 made of a metal of a substantially rectangular shape having a mount 5a of an I/O terminal 4a having a through hole at a side 5a adjacent to one side 5d and a through hole 10 formed at one side 5d has a cutout passing through the lower end of the side 5c adjacent to the one side 5d and formed with other I/O terminal 4b made of an insulator having a thermal expansion coefficient at room temperature to 100°C and larger than that of the frame 5 and smaller than that of the base 3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor element housing package (hereinafter, also referred to as an optical semiconductor package) for housing an optical semiconductor element.

[0002]

2. Description of the Related Art FIG. 3 shows an optical semiconductor package for accommodating an optical semiconductor element such as a semiconductor laser element (LD) or a semiconductor light receiving element (PD) such as a photodiode used in the conventional optical communication field. . As shown in the figure, the optical semiconductor package 1 generally has a base 3 made of a metal such as a copper (Cu) -tungsten (W) alloy. The thermal expansion coefficient of the base 3 is from room temperature (RT) to
It is about 7 × 10 ^{−6 to} 9 × 10 ⁻⁶ / ° C. at 100 ° C. The base 3 has a function of efficiently radiating the heat generated inside to the outside.

The optical semiconductor package 1 has an LD and a P on the upper surface.
It is mainly composed of a base body 3 having a mounting portion 3a on which the optical semiconductor element 2 such as D is mounted and fixed, and a frame body 5 made of a metal such as Fe—Ni—Co alloy or Fe—Ni alloy. . The thermal expansion coefficient of this frame 5 is 5 × 10 ^{−6 at} RT to 100 ° C.
/ ° C to 6 x 10 ^-6 / ° C. The frame 5 has a mounting portion 3a.
Is bonded to the upper surface of the base 3 so as to surround the. The frame 5 is for surrounding various electronic components and for mounting the input / output terminal 34 and the optical fiber 12. The input / output terminal 34, which is an insulating terminal for electrically connecting the optical semiconductor element 2 and an external electric circuit, is fitted and joined to the mounting portion 35 of the input / output terminal 34 provided on the side of the frame body 5. There is.

A through hole 10 which is an optical transmission line for optically coupling with the optical semiconductor element 2 is formed on the other side portion of the frame body 5. Around the outer opening of the frame 5 of the through hole 10, the frame 5
One end of a tubular optical fiber fixing member (hereinafter, also referred to as a fixing member) 11 made of a metal having a thermal expansion coefficient close to that of the above is joined with a brazing material such as silver brazing, or the fixing member is fixed to the through hole 10.
11 is fitted and joined. An optical isolator (not shown) for preventing returning light and an optical fiber 12 are fixed to the fixing member 11 by a metal holder 13 which is bonded with a resin adhesive or the like. In addition, the inside of the fixing member 11 is made of amorphous glass or the like and functions as a condenser lens, and at the same time, the optical semiconductor package 1
A transparent member 16 that hermetically closes the inside is fixed.

The end faces of the fixing member 11 and the metal holder 13 are fixed by YAG laser welding or the like. On the other hand, the fixing member 11 and the translucent member are fixed by brazing with a low melting point brazing material such as Au (gold) -Sn (tin) alloy having a melting point of 200 to 400 ° C.

A thermoelectric cooling element 17 such as a Peltier element is arranged on the lower surface of the optical semiconductor element 2 and
During operation, the thermoelectric cooling element 17 cools the optical semiconductor element 2 to prevent a decrease in light output and a deterioration in life due to heat generation of the optical semiconductor element 2. Further, a semiconductor element (not shown) such as an LSI for driving the optical semiconductor element 2 or for signal amplification is provided on the mounting portion 3a. The thermoelectric cooling element 17 or the heat sink may be arranged on the lower surface of the semiconductor element. Then, the electrode of the optical semiconductor element 2 is electrically connected to the line conductor 6 of the input / output terminal 34 via the bonding wire.

The input / output terminal 34 comprises a flat plate portion 7 made of ceramics and a standing wall portion 8 installed on the upper surface thereof. On the upper surface of the flat plate portion 7, a line conductor 6 made of a metallized metal layer is provided as a transmission line (input line and / or output line) for high frequency signals. This input / output terminal 34
Is for electrically connecting an external electric circuit and the optical semiconductor element 2 and hermetically closing the inside of the optical semiconductor package 1. Generally, the input / output terminal 34 is made of ceramics containing alumina as a main component, and its thermal expansion coefficient is about 6 × 10 ^{−6 to} 7 × 10 ⁻⁶ / ° C. at RT to 100 ° C.

Then, the optical semiconductor element 2 is bonded and fixed to the mounting portion 3a of the base body 3 through the thermoelectric cooling element 17 with an adhesive material such as a resin adhesive or a brazing material. Next, the electrode of the optical semiconductor element 2 is electrically connected to the line conductor 6 of the input / output terminal 34 via a bonding wire. After that, the metal holder 13 to which the optical isolator and the optical fiber 12 are fixed is welded to the fixing member 11. Next, the lid body 14 is joined to the upper surface of the frame body 5 by seam welding, brazing or the like, and the optical semiconductor element 2 and the semiconductor element are hermetically housed in the container formed of the base body 3, the frame body 5 and the lid body 14. Then, it becomes an optical semiconductor device as a product. This optical semiconductor device optically excites the optical semiconductor element 2 by a drive signal supplied from an external electric circuit, transmits and receives the excited light to and from the optical fiber 12, and transmits the light in the optical fiber 12. It is used for communication, etc., and is often used in the field of optical communication.

In recent years, the demand for high-speed and large-capacity communication has been rapidly increasing, and therefore research and development relating to high-speed and large-capacity transmission have been promoted. In particular, an optical transmission device such as an optical semiconductor device that transmits an optical signal has been attracting attention in an optical communication device, and higher output and higher speed of the optical signal have been problems for improving the transmission capacity. The optical signal of the conventional optical semiconductor device has an output of about 5 to 10 mW, and the optical semiconductor element mounted has a driving power of about 20 mW. However, in an optical semiconductor device with a higher output, the optical output has been improved to the level of 20 mW. Further, the optical semiconductor element mounted on such an optical semiconductor device is also required to have a driving power of 50 mW level. In addition, the high-frequency signal used in conventional optical semiconductor devices was in the 10 GHz band,
The frequency has been improved to the Hz band, and the speed has been further increased.

Further, conventionally, the optical semiconductor element 2 which generates a large amount of heat at the time of operation is cooled and the temperature of the optical semiconductor element 2 is kept constant to stabilize the frequency and output of the optical signal transmitted from the optical semiconductor element 2. Various cooling devices were provided for the purpose of keeping. For example, in order to efficiently diffuse the heat of the optical semiconductor element 2, a mounting base 3a of the base 3 is provided with a base made of a material having a high thermal conductivity such as Cu-W alloy, or the base 3 and the optical semiconductor element 2 are provided. The thermoelectric cooling element 17 was provided between the and.

[0011]

However, in the above-described conventional optical semiconductor package 1, since the temperature during operation reaches a maximum of about 85 ° C., the difference in thermal expansion between the base body 3, the frame body 5, and the input / output terminal 34. As a result, the optical semiconductor package 1 is distorted, and the optical output in the high temperature state during operation is reduced as compared with the case where the optical signal of the optical semiconductor element 2 in the initial state before operation is coupled to the optical fiber. Was.

In order to measure such fluctuations in the optical output, an optical semiconductor device in which an optical semiconductor element 2 of high output having an optical output of about 50 mW is housed inside an optical semiconductor package 1 was prototyped. An optical power meter was connected to the tip of the optical fiber 12 extending from the optical semiconductor device, and a test was conducted by placing the optical semiconductor device in an atmosphere of 85 ° C., and the optical output in the initial state before the test and 85 ° C. Comparing the optical output in the operating state after placing it in the atmosphere, the loss in the operating state is ± 0.4 to ±
It increased by 0.8 dB. This is a large loss that has not been seen in the past, and it has been confirmed that the optical output has a variation that cannot be used as an optical semiconductor device.

Conventionally, it has been required to suppress the fluctuation within ± 0.5 dB in the same test, but the optical semiconductor element 2 used in the conventional test has an optical output of about 20 mW,
The one used in this test has a high output that is nearly double that of the conventional one. It is obvious that this is a factor of characteristic deterioration, and it has been found that when the high-power optical semiconductor element 2 is used, the optical semiconductor package 1 causes large distortion.

In addition, since a high frequency signal that has been increased in frequency from 10 GHz band to 40 GHz band is input, 3
A resonance phenomenon of dB or more occurred. The cause of this is that unnecessary electromagnetic fields leaked from the terminals of the thermoelectric cooling element used for cooling, causing resonance that was not seen in the 10 GHz band. Therefore, the rising speed of the high-frequency signal in the 40 GHz band is 15 psec (picoseconds), which is 10 pse.
There is a problem that it is not possible to cope with the high speed required for a rising speed of about c.

Therefore, the present invention has been completed in view of the above problems, and an object thereof is to relieve the strain caused by the stress generated in the base body or the frame body by the heat during the operation of the optical semiconductor element. Therefore, it is another object of the present invention to provide an optical semiconductor package that prevents deterioration of optical coupling efficiency between an optical semiconductor element and an optical fiber and that can smoothly transmit a high frequency signal when used with a high frequency signal in the 40 GHz band.

[0016]

A package for housing an optical semiconductor element according to the present invention comprises a substantially rectangular metal base having a mounting portion on which an optical semiconductor element is mounted, and a front surface of the base. Attached so as to surround the placing portion, a through hole is formed in one side portion and a through hole formed in a side portion adjacent to the one side portion or a cut formed in an upper end of the side portion. A substantially rectangular metal frame body having an input / output terminal mounting portion formed of a notch portion is fitted into the through hole, or one end of the through hole is joined around the frame body outside opening. In a package for storing an optical semiconductor element, which comprises a tubular optical fiber fixing member and an input / output terminal fitted to the mounting portion, the base body has a coefficient of thermal expansion at room temperature to 100 ° C higher than that of the frame body. The frame is made of a large metal and the frame is adjacent to the one side. Has a notch penetrating the inside and the outside at the lower end thereof, and another input / output terminal made of an insulator having a coefficient of thermal expansion at room temperature to 100 ° C. larger than that of the frame body and smaller than that of the base body is fitted into the notch. It is characterized by being worn.

In the package for accommodating an optical semiconductor element of the present invention, the notch formed so as to penetrate the inside and outside of the lower end of the side portion of the frame having the above-mentioned structure has a coefficient of thermal expansion at room temperature to 100 ° C. Since another input / output terminal made of an insulator that is larger than the frame body and smaller than the base body is fitted, the difference in thermal expansion between the frame body and the base body is mitigated, deformation of the frame body is prevented, and optical coupling efficiency is improved. It becomes possible to hold. Therefore, stable optical coupling can be maintained between the optical semiconductor element and the optical fiber even in a high temperature state during operation, and the fluctuation of the optical output of the optical semiconductor device can be suppressed to ± 0.3 dB or less.

In the package for accommodating an optical semiconductor element of the present invention, preferably, the optical semiconductor element is mounted on the mounting portion of the base through a thermoelectric cooling element and electrically connected to the input / output terminal. The thermoelectric cooling element is electrically connected to the other input / output terminal.

In the package for accommodating an optical semiconductor element of the present invention, a connection terminal or a connection line for transmitting a high frequency signal of 40 GHz band is connected to the input / output terminal, and a connection terminal or a connection line of the thermoelectric cooling element is connected to another input / output terminal. By connecting to the side, resonance due to an unnecessary electromagnetic field leaking from the connection terminal or connection line of the thermoelectric cooling element can be reduced, and a high frequency signal can be smoothly transmitted. Therefore, the loss due to resonance in the 40 GHz band can be suppressed to 3 dB or less, and the rise time, which shows the performance of the optical semiconductor device, can be 10 psec or less.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The optical semiconductor element housing package of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an example of an embodiment of an optical semiconductor package of the present invention, and FIG. 2 is a cross-sectional view of the optical semiconductor package of FIG. 1 when viewed from the fixing member side. 1 and 2, the same members as those in FIG. 3 showing the conventional optical semiconductor package are denoted by the same reference numerals.

In FIGS. 1 and 2, 1 is an input / output terminal (hereinafter also referred to as a first input / output terminal) 4a fitted to the base 3, the frame 5, and the mounting portion 5a of the frame 5, and a frame. The optical semiconductor package is mainly composed of another input / output terminal (hereinafter, also referred to as a second input / output terminal) 4b fitted to the mounting portion 5b of the body 5. The base 3, the frame 5, the first input / output terminal 4a, the second input / output terminal 4b, the optical fiber 12, and the fixing member 11 of the tubular optical fiber 12 to which the translucent member 16 is fixed, A container for housing the optical semiconductor element 2 is formed inside.

The first input / output terminal 4a has a through hole formed in the side portion 5c adjacent to the one side portion 5d of the frame body 5 or a notch formed at the upper end of the side portion 5c so as to penetrate inside and outside. It is fitted to the mounting portion 5a composed of the parts. Further, the second input / output terminal 4b is fitted to a mounting portion 5b formed by a notch formed so as to penetrate the inside and outside of the lower end of the side portion 5c adjacent to the one side portion 5d of the frame body 5.

Then, the optical semiconductor element 2 is mounted and fixed on the mounting portion 3a on the upper surface of the base body 3, and a lid (not shown) is joined to the upper surface of the frame 5 to hermetically seal the optical semiconductor. It becomes a device.

The optical semiconductor package 1 of the present invention comprises a base 3 made of metal and a mounting portion 3 for mounting the optical semiconductor element 2 on the upper surface thereof.
a frame 5 joined so as to surround a and having mounting portions 5a, 5b of the input / output terminals 4a, 4b; and, for example, a first input / output terminal 4a capable of precise impedance control with respect to a high frequency signal, A second input / output terminal 4b capable of withstanding a high current of about 10 A is provided. That is, in the present invention, preferably, the optical semiconductor element 2 has the base 3 through the thermoelectric cooling element 17.
Mounted on the mounting portion 3a of the first input / output terminal 4
The thermoelectric cooling element 17 may be electrically connected to a, and the thermoelectric cooling element 17 may be electrically connected to the second input / output terminal 4b.

The optical semiconductor package 1 of the present invention uses the second input / output terminal 4b made of an insulator having a thermal expansion coefficient larger than that of the frame body 5 and smaller than that of the base body 3 at room temperature to 100 ° C. As a result, even if the optical output is about 20 mW exceeding 15 mW, the fluctuation can be kept within ± 0.3 dB.
This means that the fluctuation of the optical output can be reduced by suppressing the distortion of the entire optical semiconductor package 1 due to the difference in thermal expansion between the frame body 5 and the base body 3 at the second input / output terminal. If the coefficient of thermal expansion of the second input / output terminal 4b deviates from the above range, the fluctuation of the optical output becomes large at ± 0.5 to ± 0.8 dB, and it is difficult to obtain a stable optical output.

In the present invention, the first input / output terminal 4
It is preferable that the coefficient of thermal expansion of a and the coefficient of thermal expansion of the second input / output terminal 4b be the same. That is, (the coefficient of thermal expansion of the frame 5) <(the coefficient of thermal expansion of the first input / output terminal 4a = the coefficient of thermal expansion of the second input / output terminal 4b) <(the coefficient of thermal expansion of the substrate) Good. For example, the thermal expansion coefficient of the first and second input / output terminals 4a and 4b is 6.59 × 10 ⁻⁶ / ° C. (alumina ceramics, etc.), and the thermal expansion coefficient of the frame body 5 is 5.19 × 10 5.
^-6 / ° C (Fe-Ni-Co alloy or the like), and the thermal expansion coefficient of the base body 3 is 7.06 x 10 ^-6 / ° C (Cu-W alloy or the like). In addition, these thermal expansion coefficients are in RT-100 degreeC.

More preferably, when the first and second input / output terminals 4a and 4b have the same coefficient of thermal expansion and A is the same, (A-coefficient of thermal expansion of the frame 5) <3 × 10 ^-6 /
C., and (coefficient of thermal expansion of the substrate 3−A) <3 × 10 ⁻⁶ / ° C. is preferable. If it deviates from this range, the thermal expansion of the base body 3 and the frame body 5, which is suppressed by installing the frame body 5 so as to be sandwiched between the first input / output terminal 4a and the second input terminal 4b, is suppressed. It becomes difficult to suppress the distortion of the optical semiconductor package 1 caused by the difference. That is, ± 0 in the above-mentioned optical output fluctuation test.
The result is that it does not reach within 5 dB.

The first input / output terminal 4a and the second input / output terminal 4b are preferably made of the same insulator in order to have the same coefficient of thermal expansion. Then, for example, the first input / output terminal 4a is adapted to input / output a high frequency signal to / from the optical semiconductor element 2, and the width of the line conductor 6 is configured so as to match the impedance of the high frequency signal. Further, the second input / output terminal 4b is for inputting a large DC current for driving into the thermoelectric cooling element 17, and is 0.8 m in order to efficiently flow 1A DC.
As a line conductor having a width of m, it is configured to pass a large current. Conventionally, a configuration for such high frequency signals and a configuration for large current is applied to one input / output terminal,
Thermoelectric cooling element by applying to each separate input / output terminal
It is possible to reduce the influence on the high frequency signal due to the leakage of the electromagnetic field from the 17 connecting terminals and the like. In order to sufficiently suppress the influence of the electromagnetic field from the connection terminal or the like of the thermoelectric cooling element 17, it depends substantially on the distance between the line conductor 6 of the first input / output terminal 4a and the line conductor of the second input / output terminal 4b. To do. This distance is specifically 2
It should be at least mm.

As described above, the functions are shared by the first input / output terminal 4a and the second input / output terminal 4b.
The loss due to resonance generated at about 40 GHz is halved from about 6 dB to about 3 dB. As a result, the EYE characteristics of the optical module using the optical semiconductor device are not affected. The EYE characteristic is a characteristic that indicates whether or not a digital signal can be smoothly transmitted. The signal pulse generated by the pulse generator is input to the optical module, photoelectric conversion is performed in the optical module, and then the optical signal is output. Is output. At that time, evaluation is performed by performing a measurement such as outputting a rectangular pattern digital signal from an optical fiber. Then, if there is a recognition point other than the points 1, 0, it is processed as an error. When there is resonance, the occurrence of error mode is high. The pass / fail judgment of the digital signal is represented by how open the locus of the rectangular wave is.
Generally, the space obtained from the locus of a rectangular wave is called a window, and if a point on the window occurs, it is recognized as an error without being determined as 1,0.

As described above, in order to reduce the loss due to resonance and improve the EYE characteristics, the distance between the line conductors of the first input / output terminal 4a and the second input / output terminal 4b is set as described above. It is preferable to set it to 2 mm or more. This reduces the distance to 0.
It is derived from the experiment in case of separating by 2 mm. When it is 2 mm or more, the loss due to resonance becomes small, but when it is less than 2 mm, the loss due to resonance becomes close to the conventional one and it is difficult to use it as a good product. Become.

A metal holder 13 to which an optical fiber 12 and an optical isolator (not shown) for preventing returning light are adhered with a resin adhesive is attached to the end surface of the fixing member 11 on the outer side of the frame 5.
It is joined by G laser welding or the like. Further, a thermoelectric cooling element 17 such as a Peltier element is arranged on the lower surface of the optical semiconductor element 2 and cools it when the optical semiconductor element 2 operates.

The optical semiconductor element 2 is placed on the mounting portion 3a.
A semiconductor element (not shown) such as an LSI for driving or signal amplification is provided, and a thermoelectric cooling element 17 or a heat sink made of Cu-W alloy may be arranged on the lower surface of the semiconductor element. Then, the optical semiconductor element 2 and the semiconductor element are connected via a bonding wire, an internal wiring pattern (not shown) or the like, and the semiconductor element is connected to the first input / output terminal 4a by a bonding wire. Then, each electrode of the optical semiconductor element 2 is electrically connected to the external lead terminal provided outside the frame body 5 of the first input / output terminal 4a via the bonding wire.

The substantially quadrangular base 3 functions as a support member for supporting the optical semiconductor element 2 and as a heat radiating plate for radiating the heat of the optical semiconductor element 2, and the optical semiconductor element 2 is mounted on the substantially central portion of the upper surface thereof. It has a mounting portion 3a for. Placement part 3
The optical semiconductor element 2 has a thermoelectric cooling element 17 in between a
While being bonded via an adhesive such as a u-Si (silicon) brazing material, the heat of the optical semiconductor element 2 is transferred to the mounting portion 3a via this adhesive, and is efficiently radiated to the outside. The operability of the element 2 is improved. This base 3 is C
It is made of a metal having a thermal conductivity of 100 W / mK or more, such as a u-W alloy. For example, a Cu-W alloy is produced by impregnating a porous W sintered body with Cu.

On the surface of the substrate 3, a metal having excellent corrosion resistance and wettability with the brazing material, specifically, a thickness of 0.5 to
It is preferable that a Ni layer of 9 μm and an Au layer of 0.5 to 5 μm in thickness be sequentially deposited by a plating method so as to effectively prevent oxidative corrosion of the base body 3 and to form a thermoelectric cooling element 17 on the upper surface of the base body 3. Can be firmly adhered.

A frame 5 having a substantially quadrangular shape in plan view is joined to the upper surface of the base 3 so as to surround the mounting portion 3a of the optical semiconductor element 2, and the optical semiconductor element is provided inside the frame 5. Two
A cavity is formed to accommodate the. This frame 5 is F
It is made of a metal such as an e-Ni-Co alloy. Further, the frame body 5 is
The metal ingot is manufactured into a predetermined shape by subjecting the metal ingot to a conventionally known metal processing method such as rolling or punching.

Next, the frame 5 has a through hole 10 for transmitting light on one side 5d and the side 5 adjacent to the one side 5d.
It is manufactured in a shape having a mounting portion 5a of the first input / output terminal 4a and a mounting portion 5b of the second input / output terminal 4b in c.
The through hole 10 is formed in a predetermined shape by drilling a hole in the one side portion 5d of the frame body 5. Mounting parts 5a, 5b
Are formed by cutting or punching with a milling cutter. Further, as a means for electrically connecting the optical semiconductor element 2 and an external electric circuit, a thickness of 0.5 for connecting a bonding wire, an external lead terminal, etc. to a part of the inner surface and a part of the outer surface of the frame body 5. ~ 9μm Ni layer and thickness 0.5 ~ 5μ
It is advisable to deposit a metal layer such as Au layer of m by a plating method.

Further, the fixing member 11 is provided on the frame body 5 by joining one end around the outside opening of the frame body 5 of the through hole 10 or by fitting it into the through hole 10 and joining the outer peripheral surface thereof. The fixing member 11 is formed in a tubular shape so that an optical signal is transmitted inside, is made of a metal such as Fe-Ni-Co alloy or Fe-Ni alloy, and is joined through a brazing material such as silver brazing. It
Further, the fixing member 11 is processed and manufactured into a predetermined shape by the same processing method as that of the substrate 3, and a Ni layer having a thickness of 0.5 to 9 μm or an Au layer having a thickness of 0.5 to 5 μm is formed on the surface thereof for the purpose of preventing oxidation.
It is advisable to deposit a metal layer such as a layer by a plating method.

Inside the fixing member 11, a light-transmitting member 16 made of amorphous glass or the like, which functions as a condenser lens and closes the inside of the optical semiconductor package 1, is formed on the surface of the joining portion by metallization. The layers are joined with a low melting point brazing material such as an Au—Sn alloy having a melting point of 200 to 400 ° C. This translucent member 16 has a coefficient of thermal expansion of 4 × 10 ^{−6 to} 12
It is made of sapphire (single crystal alumina) having a temperature of × 10 ⁻⁶ / ° C. (room temperature to 400 ° C.), amorphous glass, or the like, and has a spherical shape, a hemispherical shape, a convex lens shape, a rod lens shape, or the like. That is, the translucent member 16
Allows the light such as the external laser light transmitted through the optical fiber 12 to be input to the optical semiconductor element 2 or
It is a condensing member for inputting the light such as the laser light output in 1) into the optical fiber 12. When the translucent member 16 is, for example, an amorphous glass having no crystal axis, silicon oxide (SiO 2
₂ ), a lead-based material containing lead oxide (PbO) as a main component, or a borosilicate-based material containing boric acid or silica sand as a main component.

Further, even if the coefficient of thermal expansion of the translucent member 16 is different from that of the frame 5, the fixing member 11 absorbs and relaxes the stress due to the difference in thermal expansion, so that the crystal axis is due to the stress. It is difficult to cause a change in the refractive index of light by aligning the directions. Therefore, by using this translucent member 16, the light coupling efficiency between the optical semiconductor element 2 and the optical fiber 12 can be increased.

The first input / output terminal 4a is joined to the substantially rectangular flat plate portion 7 having the line conductor 6 formed on the upper surface thereof and the upper surface of the flat plate portion 7 with the line conductor 6 sandwiched therebetween. It comprises a substantially rectangular parallelepiped standing wall portion 8 formed so as to block the inside and the outside. The standing wall portion 8 has a ground conductor formed of a metallized layer or the like on its upper surface, and a ground conductor formed on its side surface so as to extend the ground conductor. The flat plate portion 7 and the standing wall portion 8 are made of a dielectric material such as aluminum oxide ceramics, aluminum nitride ceramics, glass ceramics.

The line conductor 6 and the ground conductor on the upper surface of the flat plate portion 7 are formed of W, Mo, Mn or the like. For example, a metal paste obtained by adding and mixing an organic solvent or a solvent to a powder of W or the like,
The ceramic green sheets for the flat plate portion 7 and the standing wall portion 8 are formed on the flat plate portion 7 and the standing wall portion 8 by printing and applying a predetermined pattern by a screen printing method. On the surface of the line conductor 6 and the ground conductor, a Ni layer having a thickness of 0.5 to 9 μm and a thickness of 0.5 to 5 are formed in order to prevent oxidation and firmly connect the bonding wire, the external lead terminal 18 and the like.
It is advisable to deposit a metal layer such as an Au layer having a thickness of μm by a plating method.

A lid (not shown) made of Fe-Ni-Co alloy or the like is joined to the upper surface of the frame 5 by seam welding or the like to hermetically seal the optical semiconductor element 2 in the optical semiconductor package 1. To do.

The optical semiconductor package 1 of the present invention comprises an LD,
In the case of optical communication in which an optical semiconductor element 2 such as a PD and a semiconductor element such as an LSI are housed, a through hole 10 penetrating the inside and outside is formed in one side portion 5d and a side portion 5c adjacent to the one side portion 5d is provided with a first hole. Mounting part 5 for the first and second input / output terminals 4a and 4b
The frame body 5 formed by forming a and 5b is bonded to the upper surface of the base body 3. A cylindrical fixing member 11 is joined around the outer opening of the frame body 5 of the through hole 10, and a transparent member 16 is joined inside the fixing member 11. The first and second input / output terminals 4 are attached to the mounting portions 5a and 5b.
A and 4b are fitted and joined. Then, the optical semiconductor element 2 and the semiconductor element are mounted on the mounting portion 3a via the thermoelectric cooling element 17 and are connected to each other by bonding wires. Further, the semiconductor element and one end of the line conductor 6 of the first input / output terminal 4a are connected by a bonding wire, and the thermoelectric cooling element 17
And the line conductor of the second input / output terminal 4b are connected by a lead wire or the like. Then, the lid is joined to the upper surface of the frame 5 by seam welding or the like. Thereafter, a metal holder 13 in which an optical fiber 12 and an isolator for preventing returning light are adhered with a resin adhesive to the outer end surface of the frame 5 of the fixing member 11 is joined by YAG laser welding or the like to obtain a product. Optical semiconductor device.

Thus, in the optical semiconductor package of the present invention, the thermoelectric cooling element is connected to the second input / output terminal, and 40 GHz
The high frequency signal in the z band or the like can be functionally separated so as to flow through the first input / output terminal 4a, in which case the loss due to resonance of the high frequency signal can be reduced and the high frequency signal can be smoothly transmitted. Further, distortion due to the difference in thermal expansion between the frame body and the substrate is relaxed, deformation of the frame body is prevented, and deterioration of the optical coupling efficiency is effectively prevented. As a result, when an optical semiconductor device is formed using the optical semiconductor package of the present invention, the optical output of the optical semiconductor element can be efficiently transmitted to the optical fiber.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention.

[0046]

In the package for accommodating an optical semiconductor element of the present invention, the substantially rectangular metal base having the mounting portion on which the optical semiconductor element is mounted has a coefficient of thermal expansion at room temperature to 100 ° C. It is made of a metal that is larger than the frame, is attached to the upper surface of the base so as to surround the mounting portion, has a through hole in one side, and a through hole formed in the side adjacent to the one side. The substantially rectangular metal frame in which the mounting portion of the input / output terminal, which is formed by the notch formed so as to penetrate the inside or the outside at the upper end of the hole or the side portion, is formed on the side portion adjacent to one side portion. A notch that penetrates the inside and outside is formed at the lower end, and another input / output terminal made of an insulator whose thermal expansion coefficient at room temperature to 100 ° C is larger than that of the frame body and smaller than that of the base body is fitted in the notch. This reduces the difference in thermal expansion between the frame and the substrate, preventing deformation of the frame and If the efficiency and it is possible to satisfactorily retain. Therefore, stable optical coupling can be maintained between the optical semiconductor element and the optical fiber even at high temperature during operation,
As an optical semiconductor device, the fluctuation of the optical output can be suppressed to ± 0.3 dB or less.

In the optical semiconductor element accommodating package of the present invention, preferably, the optical semiconductor element is mounted on the mounting portion of the base body through the thermoelectric cooling element and electrically connected to the input / output terminal. , The thermoelectric cooling element is electrically connected to the other input / output terminal, so that the connecting terminal or the connecting wire for transmitting the high frequency signal of 40 GHz band is connected to the input / output terminal, and the connecting terminal or the connecting terminal of the thermoelectric cooling element is connected. By connecting the wire to the other input / output terminal side, resonance due to an unnecessary electromagnetic field leaking from the connection terminal of the thermoelectric cooling element or the connection wire can be reduced, and a high frequency signal can be smoothly transmitted. Therefore, the loss due to resonance in the 40 GHz band can be suppressed to 3 dB or less, and the rise time, which shows the performance of the optical semiconductor device, can be 10 psec or less.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an embodiment of an optical semiconductor element housing package of the present invention.

FIG. 2 is a cross-sectional view of the package for storing an optical semiconductor element of the present invention when viewed from the optical fiber fixing member side.

FIG. 3 is a sectional view of a conventional package for storing an optical semiconductor element.

[Explanation of symbols]

1: Package for storing optical semiconductor elements 2: Optical semiconductor element 3: Base 3a: Placement part 4a: First input / output terminal 4b: second input / output terminal 5: frame 5a: Mounting part for the first input / output terminal 5b: Mounting portion for second input / output terminal 5c: side part 5d: One side 10: Through hole 11: Optical fiber fixing member 12: Optical fiber

Claims (2)

[Claims] 1. A substantially rectangular metal base having a mounting portion on which an optical semiconductor element is mounted, and a side portion attached to the upper surface of the base so as to surround the mounting portion. A through hole is formed in the side wall and a mounting portion for an input / output terminal is formed, which is formed of a through hole formed in a side portion adjacent to the one side portion or a notch formed in an upper end of the side portion. A rectangular metal frame body, a tubular optical fiber fixing member that is fitted into the through hole or one end of which is joined to the periphery of the frame body outside opening of the through hole, and is fitted to the mounting portion. In the package for storing an optical semiconductor element having an input / output terminal, the base body is made of a metal having a coefficient of thermal expansion at room temperature to 100 ° C. larger than that of the frame body, and the frame body is adjacent to the one side portion. A notch that penetrates the inside and outside is formed at the lower end of the side part that A package for accommodating an optical semiconductor element, characterized in that another input / output terminal made of an insulator having a coefficient of thermal expansion at room temperature to 100 ° C. larger than that of the frame body and smaller than that of the base body is fitted in the notch. 2. The optical semiconductor element is mounted on the mounting portion of the base through a thermoelectric cooling element and is electrically connected to the input / output terminal, and the thermoelectric cooling element is the other one. The package for accommodating an optical semiconductor element according to claim 1, wherein the package is electrically connected to the input / output terminal of.