JP2003218440A - Package for housing optical semiconductor element and optical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the heat radiating property of an optical semiconductor element mounted on the upper surface of a metallic substrate through a mounting substrate. <P>SOLUTION: The thickness of the metallic substrate is adjusted to 0.1-0.5 mm. In addition, the mounting substrate has a metal-carbon complex A obtained by impregnating a metallic component n containing at least one kind selected from among Ag, Ti, Cr, Zr, and W in an amount of 0.2-10 wt.% and Cu in an amount of 90-99.8 wt.% into a carbonaceous base material m in which aggregates of unidirectional carbon fibers 1 are scattered, a stainless steel layer X and a Cu layer Y respectively laminated upon the upper and lower surfaces of the complex A, and a plated metallic layer b formed to coat the surface of the Cu layer Y. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a semiconductor laser (L
D), an optical semiconductor device housing package for housing an optical semiconductor device such as a photodiode (PD), and an optical semiconductor device.

[0002]

2. Description of the Related Art A conventional package for storing an optical semiconductor element (hereinafter, also referred to as an optical semiconductor package) is shown in FIGS. 4 and 5 in a perspective view and a sectional view, respectively (see Japanese Patent Laid-Open No. 2001-144361). In this optical semiconductor package, the optical semiconductor element 15 has an anisotropic high thermal conductivity plate 16 (having a thermal conductivity of 250 W in the plane direction) on the upper surface.
/ M · K or more), and has a base 11 having a thickness of 0.1 to 0.5 mm, and is joined to the upper surface of the base 11 so as to surround the base 11a. A metal frame 12 having a tubular optical fiber fixing member 13 for holding an optical fiber, and a window 14 provided in the optical fiber fixing member 13 are provided.

The thickness of the substrate 11 is such that the hermeticity of the optical semiconductor package is 1 × 10 ⁻⁸ at as a leak amount of helium (He) gas.
The thickness is kept within a range of m · cc / sec or less, and is made thin within a range in which it is not deformed by thermal stress at the time of brazing or mechanical stress at the time of screwing the base 11 to the base plate (external electric circuit board). Therefore, the optical semiconductor package can be downsized by reducing its height.

Further, the anisotropic high thermal conductive plate 16 has 50 in the plane direction.
Carbon (C) -graphite (C) fiber composite plate having a thermal conductivity of 0 W / m · K and 80 W / m · K in the thickness direction, or 300 W / m · K in the plane direction and 100 W / in the thickness direction It is made of a copper (Cu) -graphite fiber composite plate having a thermal conductivity of m · K, and the thickness of the base 11 is made thin so that the heat of the optical semiconductor element 15 can be efficiently transferred to the external electric circuit board. . Also,
The coefficient of thermal expansion in the plane direction of the anisotropic high thermal conductive plate 16 is 5 in each case.
× a ^{10 -6 ~10 × 10 -6 / ℃} , since it is close to the thermal expansion coefficient of the base 11, the thermal distortion of the substrate 11 and the anisotropic high thermal conduction plate 16 small, thus joining them Can be strengthened.

Further, since the base 11 is thin, the anisotropic high thermal conductive plate 16 also functions as an appropriate reinforcing plate for preventing the warp deformation of the base 11. That is, the anisotropic high thermal conductive plate 16 includes a portion on which the optical semiconductor element 15 is mounted, and is bonded to 50% or more of the area of the upper surface of the base 11 surrounded by the frame body 12. Has a reinforcing effect. Further, the portion of the frame body 12 in contact with the base body 11 can be reinforced by forming a rib structure.

[0006]

However, in the above conventional example, since the anisotropic high thermal conductive plate 16 does not have a small thermal conductivity in the surface direction of the upper surface of the substrate 11, the heat of the optical semiconductor element 15 is transferred in the surface direction. However, since the heat conductivity in the thickness direction is as small as about 80 to 100 W / m · K, the heat transfer efficiency in the thickness direction decreases as the amount of heat of the optical semiconductor element 15 increases. Therefore, the transfer of heat from the base 11 to the external electric circuit board is impaired, and the heat contained in the anisotropic high thermal conductive plate 16 causes the optical semiconductor element 15 to reach a high temperature, causing malfunction or thermal destruction of the optical semiconductor element 15. There was a problem such as doing.

Further, since the temperature difference between the base 11 and the anisotropic high thermal conductive plate 16 becomes large due to the heat contained in the anisotropic high thermal conductive plate 16, even if the anisotropic high thermal conductive plate 16 functions as a reinforcing plate. Alternatively, even if the portion of the frame body 12 in contact with the base body 11 has a rib structure, the anisotropic high thermal conductive plate 16 itself warps and deforms, and since the base body 11 is thin, the base body 11 also warps. Cause deformation. Therefore, the optical axes of the optical semiconductor element 15 and the optical fiber are deviated, and the optical coupling efficiency thereof is lowered,
There is a problem that the operability of the optical semiconductor element 15 is lowered.

Further, the airtightness test inside the optical semiconductor package is performed by filling the inside with He gas and measuring the leak amount, but the anisotropic high thermal conductive plate 16 generally has a high porosity. Therefore, He gas is an anisotropic high thermal conductive plate.
May be trapped in 16. That is, He gas may be trapped between the carbon and the graphite fiber or between the graphite fibers. As a result, there is a problem that even an optical semiconductor package having good airtightness may be erroneously determined as a defective product having poor airtightness.

In order to solve such a problem, the anisotropic high thermal conductive plate 16 has a thermal conductivity of about 250 W / m · K not only in the plane direction but also in the thickness direction and has pores on the surface. It is conceivable to use a dense copper-tungsten (W) alloy or the like, but since the specific gravity is large, the optical semiconductor package itself becomes heavy. Therefore, it will be out of the trend of recent weight reduction of optical semiconductor packages.

The anisotropic high thermal conductive plate 16 is an optical semiconductor device.
It also functions as a substrate that supports 15, that is, a so-called mounting substrate.

Therefore, the present invention has been completed in view of the above problems, and an object thereof is to have a high thermal conductivity not only in the plane direction (lateral direction) but also in the thickness direction (vertical direction) and at the surface. By using a dense mounting board with no pores,
It is an object of the present invention to provide an optical semiconductor package which has a good operability of the optical semiconductor element, is suitable for the airtightness test inside the optical semiconductor package, and is small and lightweight.

[0012]

A package for storing an optical semiconductor element according to the present invention is a substantially rectangular metal base having a mounting portion on the top surface of which an optical semiconductor element is mounted via a mounting substrate. An optical fiber fixing member mounting portion, which is joined to the upper surface of the base body so as to surround the mounting portion, has a through hole on one side, and an input / output terminal mounting portion having a notch or a through hole on the other side. The formed frame body, a tubular optical fiber fixing member which is fitted to the optical fiber fixing member mounting portion or one end of which is joined to the circumference of the frame body outside opening of the through hole, and the input / output terminal In a package for accommodating an optical semiconductor element having an input / output terminal fitted in a mounting portion, the thickness of the base is 0.1 to 0.5 mm, and the mounting substrate is an assembly of unidirectional carbon fibers. Silver, titanium, and chromium in the carbonaceous base material dispersed inside At least one of 0.2 to 10 wt% and copper of zirconium and tungsten 9
A metal-carbon composite impregnated with a metal component containing 0 to 99.8% by weight, a stainless steel layer and a copper layer sequentially stacked on the upper and lower surfaces of the metal-carbon composite, and a copper layer deposited on the surface of the copper layer And a metal plating layer.

With the package for storing an optical semiconductor element of the present invention, the mounting substrate on which the optical semiconductor element is mounted has a high thermal conductivity not only in the plane direction but also in the thickness direction and has pores on the surface. Since it will be a precise thing without
The operability of the optical semiconductor element can be improved, and the airtightness inside the optical semiconductor package can be stably maintained.

In the package for accommodating an optical semiconductor device of the present invention, the thickness of the stainless steel layer is preferably 5
˜50 μm, and the thickness of the copper layer is 100 to 300 μm.

With the above structure, the package for accommodating an optical semiconductor element of the present invention can further improve the transferability of heat generated when the optical semiconductor element operates.

The optical semiconductor device of the present invention includes an optical semiconductor package of the present invention, an optical semiconductor element mounted and fixed on a mounting portion and electrically connected to input / output terminals, and bonded to the upper surface of a frame. It is characterized by including the lid body.

The optical semiconductor device of the present invention can provide a highly reliable optical semiconductor device using the optical semiconductor package of the present invention having the above-mentioned configuration.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The package for storing an optical semiconductor element of the present invention will be described in detail below. 1 and 2 show an example of an embodiment of an optical semiconductor package of the present invention. FIG. 1 is a perspective view of the optical semiconductor package, FIG. 2 is a sectional view of the optical semiconductor package, and FIG. 3 is an optical semiconductor package. FIG. 3 is a partially enlarged cross-sectional view of the mounting board of FIG.

1 and 2, 1 is a base, 2 is a frame, 3 is an optical fiber fixing member (hereinafter referred to as a fixing member), 4 is a window, 5 is an optical semiconductor element, 6 is a mounting substrate, and 7 is a mounting substrate. Are input / output terminals. The base body 1, the frame body 2, the fixing member 3, the window 4, and the input / output terminal 7 mainly constitute a container that houses the optical semiconductor element 5 and the mounting substrate 6.

The substrate 1 of the present invention is made of Cu-W alloy, Fe-
It is made of a metal such as Ni alloy or Fe-Ni-Co alloy, and functions as a so-called support substrate on which the optical semiconductor element 5 is mounted and fixed on the mounting portion 1a on the upper surface thereof via the mounting substrate 6. The base 1 also functions as a so-called heat dissipation plate that efficiently transfers the heat of the optical semiconductor element 5 to an external electric circuit board (not shown). Further, screw holes 1b are provided at the opposite ends of the base 1.
Is formed, and is fixed by screwing the screw through the screw hole 1b and fixing it to the external electric circuit board.

In the present invention, the mounting substrate 6, which also functions as a heat dissipation plate, is fixed to the upper surface of the base 1, so that the heat generated during the operation of the optical semiconductor element 5 is efficiently transferred to the external electric circuit substrate. Further, the heat transfer efficiency can be further improved by reducing the thickness of the base body 1 to some extent. Further, by reducing the thickness of the base body 1, it is possible to reduce the height of the optical semiconductor package, which is suitable for recent trends.

The substrate 1 has a thickness of 0.1 to 0.5 mm. 0.1
If it is less than mm, the rigidity of the substrate 1 is significantly reduced, and the substrate 1
The base body 1 is likely to be warped when brazing the frame body 2 to the frame body 2 or when screwing to the external electric circuit board. Therefore, the optical axes of the optical semiconductor element 5 and the optical fiber (not shown) are deviated, the optical coupling efficiency between them is lowered, and the operability of the optical semiconductor element 5 is lowered. If it exceeds 0.5 mm, burrs and the like are likely to occur during press working of the base body 1, processability is impaired, and heat is transferred from the mounting substrate 6 having a very high thermal conductivity as compared with the base body 1 to the base body 1. It becomes difficult to efficiently transfer heat to the external electric circuit board. It is preferable that the outer dimensions of the base body 1 exhibiting the effect of the thickness as described above be a rectangle of about 40 mm square or less. If it exceeds 40 mm square, the optical semiconductor package becomes large in size, and the substrate 1 is likely to be largely warped, bent, or wavy. More preferably 10 mm square to 40
mm square is good. Specifically, it is a rectangle of about 20 mm x 40 mm or less, and more preferably (10 to 14 mm) x (28 to 32 m).
m).

The base body 1 is produced in a predetermined shape by subjecting the ingot of the material to a conventionally known metal working such as rolling or pressing. Further, it is preferable that a metal having excellent corrosion resistance, specifically, a Ni layer having a thickness of 0.5 to 9 μm and a gold (Au) layer having a thickness of 0.5 to 9 μm are sequentially deposited on the surface by a plating method, It is possible to effectively prevent the base body 1 from being oxidized and corroded.

The frame 2 to be joined (brazed) so as to surround the mounting portion 1a on the upper surface of the base 1 has an optical fiber fixing member attaching portion (hereinafter, fixing member attaching portion) having a through hole on one side. 3a) having an input / output terminal mounting portion 7a formed by a notch or a through hole on the other side and made of a metal such as Fe—Ni alloy or Fe—Ni—Co alloy.

A cylindrical fixing member 3 for fixing a holder (not shown) to which an optical fiber is adhered is fitted to the fixing member attaching portion 3a, and is joined with a brazing material such as silver (Ag) wax. To be done. Alternatively, one end of the fixing member 3 is joined to the peripheral portion of the opening on the outer surface side of the frame body 2 of the fixing member attaching portion 3a with a brazing material such as silver (Ag) brazing. The fixing member 3 is made of a metal such as Fe-Ni alloy or Fe-Ni-Co alloy, and is made of, for example, Fe.
When it is made of a —Ni—Co alloy, it is formed into a predetermined shape by subjecting an ingot of this alloy to metal working such as rolling and pressing. Further, in order to effectively prevent oxidative corrosion, it is preferable that a Ni layer having a thickness of 0.5 to 9 μm and an Au layer having a thickness of 0.5 to 9 μm be sequentially deposited on the surface by a plating method.

A window 4 made of amorphous glass or the like, which functions as a condenser lens and closes the inside of the optical semiconductor package, is formed on the inner peripheral surface of the fixing member 3 on the surface of the joint portion. 200-400 through layers
It is joined with a low melting point brazing material such as Au-tin (Sn) alloy having a melting point of ° C.

The window 4 has a coefficient of thermal expansion of 4 × 10 ⁻⁶ or more.
It is made of sapphire (single crystal alumina) of 12 × 10 ^-6 / ° C. (room temperature to 400 ° C.), amorphous glass, etc., and has a spherical shape, a hemispherical shape, a convex lens shape, a rod lens shape, or the like. And
Used as a condensing member for inputting light such as external laser light transmitted through the optical fiber to the optical semiconductor element 5 or inputting light such as laser light output from the optical semiconductor element 5 to the optical fiber. . When the window 4 is, for example, amorphous glass having no crystal axis, silicon oxide (Si
O 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 is used. Even if the coefficient of thermal expansion of this window 4 is different from that of the substrate 1, the fixing member 3 absorbs and relaxes the stress due to the difference in thermal expansion, so that the crystal axis is aligned in a certain direction due to the stress to refract light. It is unlikely that the rate will change. Therefore, by using such a window 4, it is possible to increase the light coupling efficiency between the optical semiconductor element 5 and the optical fiber.

The input / output terminal mounting portion 7a is joined with an input / output terminal 7 for inputting / outputting a high frequency signal of the optical semiconductor package and having a function of closing the inside of the optical semiconductor package with a brazing material such as Ag solder. . The input / output terminal 7 is made of alumina (Al ₂ O ₃ ) ceramics or aluminum nitride (A
1N) an insulator such as ceramics, and a metallized layer 7b as a wiring conductor formed on the surface of the insulator so as to conduct the inside and outside of the optical semiconductor package. Further, the electrode of the optical semiconductor element 5 is electrically connected to the inside of the frame 2 of the metallized layer 7b by a bonding wire.

The input / output terminal 3 is made into a paste by adding and mixing an appropriate organic binder, a solvent, etc. to a raw material powder to be an insulator, and this paste is made into a ceramic green by a doctor blade method or a calendar roll method. On the sheet, W, molybdenum (M
o), powder of manganese (Mn), etc., mixed with an organic solvent and a solvent to obtain a metal paste, which is previously printed and applied in a desired shape by a conventionally known screen printing method, and sintered at a high temperature of about 1600 ° C. It is produced by

The insulator of the input / output terminal 3 has a function of electrically insulating the frame body 2 and the metallized layer 7b, and the material thereof is appropriately selected according to the characteristics such as dielectric constant and thermal expansion coefficient. To be done. For example, it is made of Al ₂ O ₃ ceramics or the like.

Further, the lead terminal 8 is bonded to the upper surface of the metallized layer 7b outside the frame body 2 through a brazing material such as Ag solder. The lead terminal 8 is made of a material having a coefficient of thermal expansion close to that of the input / output terminal 7 in order to strengthen the connection with the input / output terminal 7. For example, lead terminal 8
When the insulator of the input / output terminal 7 is made of Al ₂ O ₃ ceramics, it is preferable to be made of Fe—Ni alloy, Fe—Ni—Co alloy, or the like.

The mounting substrate 6 of the present invention functions as a support substrate for supporting the optical semiconductor element 5 on the upper surface of the base body 1 and as a heat dissipation plate for efficiently transmitting the heat of the optical semiconductor element 5 to the base body 1. Since the mounting board 6 also functions as a heat dissipation plate, the heat of the optical semiconductor element 5 can be efficiently transferred to the external electric circuit board even if the thickness of the substrate 1 is reduced. Specifically, the thermal conductivity of the mounting substrate 6 is 350 to 400 both in the direction perpendicular to the surface of the mounting portion 1a of the optical semiconductor element 5 and in the direction parallel thereto.
A thermal conductivity of about W / m · K can be obtained.

The mounting substrate 6 is shown in FIG. 3 in a partially enlarged sectional view. l is a unidirectional carbon fiber, m is a carbonaceous base material, n is at least one of silver (Ag), titanium (Ti), chromium (Cr), zirconium (Zr), and tungsten (W) in an amount of 0.2 to 10 A metal component containing 90 wt% and 90 to 99.8 wt% Cu, A is a metal-carbon composite, and an aggregate of unidirectional carbon fibers 1 is dispersed in a carbonaceous base material m impregnated with the metal component n. Consists of Further, X is a stainless steel layer, Y is a Cu layer, b is a metal plating layer composed of a Ni plating layer, a Cu plating layer, etc., and a stainless steel layer X and a Cu layer Y are formed on the upper and lower surfaces of the metal-carbon composite A. The mounting substrate 6 is formed by sequentially stacking and depositing the metal plating layer b on the surface of the Cu layer Y.

The metal-carbon composite A is produced, for example, by the following steps [1] to [5].

[1] A block obtained by binding a bundle of unidirectional carbon fibers 1 with carbon is crushed into small aggregates of small unidirectional carbon fibers l, and the crushed unidirectional carbon fibers l are crushed.
The aggregates are collected and immersed in a solution of thermosetting resin such as phenol resin in which fine powder such as solid pitch or coke is dispersed. In addition, the size of the small block obtained by crushing the block is about 0.1 to 1 m on a side converted to a cube.
m.

[2] This is dried and a predetermined pressure is applied and heated to cure the thermosetting resin portion.

[3] Phenol resin and fine powder of pitch or coke are carbonized by firing at high temperature in an inert atmosphere to obtain a carbonaceous base material m. The carbonaceous base material m itself has a large thermal conductivity of 200 to 300 W / m · K,
It also functions as a heat transfer path for heat generated by the optical semiconductor element 5.

[4] On the other hand, Ag, T in molten Cu
At least one selected from i, Cr, Zr, W is 0.2
-10% by weight and 90 to 99.8% by weight of Cu are contained in the carbonaceous matrix m at high temperature and pressure (about 13%).
The block is impregnated at 00 ° C and about 100 MPa. The impregnated metal component n is a lump or a thin plate,
It will be dispersed in the carbonaceous base material m. This block is cut into a plate shape to prepare a plate that becomes the metal-carbon composite A.

[5] This plate is processed into a desired shape to produce a metal-carbon composite A.

In the mounting substrate 6 of the present invention, the stainless steel layer X and the Cu layer Y are bonded by diffusion bonding under high temperature and high pressure so that they are bonded to the upper and lower surfaces of the metal-carbon composite A. . The metal-carbon composite A and the stainless steel layer X are bonded very strongly by mutual diffusion of the C component and the Fe component. Further, on the surface of the Cu layer Y, a metal plating layer b such as a Ni plating layer or a Cu plating layer is provided.
Is formed. The metal plating layer b has a function of strengthening the joint between the substrate 1 and the optical semiconductor element 5 with solder or the like, and also has a function of efficiently transmitting heat of the optical semiconductor element 5.

With this structure, the heat of the optical semiconductor element 5 is applied to the carbonaceous matrix m and the unidirectional carbon fiber inside the metal-carbon composite A through the Cu layer Y and the stainless steel layer X. It is transmitted in random directions via 1 and the metal component n, and further transmitted to the substrate 1 having a thickness of 0.1 to 0.5 mm. Then, the heat is transferred from the base 1 to the external electric circuit board.

The metal-carbon composite A (coefficient of thermal expansion: 7)
Stainless steel layer X (coefficient of thermal expansion: 11 × 10 ^{-6 to} 14 × 10 ^-6 / ° C) bonded to the upper surface of × 10 ^-6 to 10 × 10 ^-6 / ° C.
Since the bonding with the metal-carbon composite A is extremely strong, the strain due to thermal expansion is suppressed, and it becomes close to the thermal strain of the metal-carbon composite A. Further, in the metal-carbon composite A, since the preferable thickness of the Cu layer Y diffusion-bonded to the surface of the stainless steel layer X is relatively thin, 100 to 300 μm, the Cu layer Y is unlikely to be affected by thermal strain. Therefore,
The mounting substrate 6 as a whole is approximately close to the thermal expansion coefficient of the metal-carbon composite A, and the optical semiconductor element 5 close to the thermal expansion coefficient can be firmly bonded.

The thickness of the stainless steel layer X is 5
~ 50μm is good. If it is less than 5μm, it is very difficult to produce the stainless steel layer X having high rigidity.
When it exceeds, the thickness of the stainless steel layer X having a relatively low thermal conductivity becomes large, and thus it is difficult to efficiently dissipate the heat of the optical semiconductor element 5 to the outside. Further, in this case, it becomes difficult for the metal-carbon composite A to suppress the thermal strain due to the thermal expansion of the stainless steel layer X, and the thermal strain of the entire mounting substrate 6 is reduced to the metal-carbon composite A, that is, the optical semiconductor element 5. It is difficult to approximate the thermal strain due to thermal expansion of. As a result, the optical semiconductor element 5 is peeled off from the mounting substrate 6, and the optical semiconductor element 5 is removed.
It becomes difficult to dissipate the heat of the outside efficiently.

The thickness of the Cu layer Y is preferably 100 to 300 μm, and if it is less than 100 μm, it becomes difficult to efficiently transfer the heat of the optical semiconductor element 5 in the lateral direction (parallel to the surface of the mounting portion 2a). . The Cu layer Y efficiently transfers heat of the optical semiconductor element 5 in the lateral direction. If it exceeds 300 μm, the thickness
Since it is directly bonded to the base body 1 having a thickness of 0.1 to 0.5 mm via the metal plating layer b, thermal strain may occur in the base body 1 due to the difference in thermal expansion coefficient between the Cu layer Y and the base body 1, The substrate 6 may peel off from the base 1.

Further, since the metal-carbon composite A is impregnated with the metal component n, the adhesion of the carbonaceous base material m becomes very good. Therefore, the heat of the optical semiconductor element 5 is efficiently transferred inside the mounting substrate 6 and is reliably transferred to the external electric circuit board via the base 1.

When the metal component n is composed of Ag and Cu, the metal component n and the carbonaceous base material m have high wettability between them, and thus the adhesion is very high. Further, the metal component n is T
When at least one of i, Cr, Zr, and W and Cu is formed, the metal component n and the carbonaceous base material m form a carbon compound of Ti, Cr, Zr, and W between them. The adhesion is very high. Ag, Ti, Cr, Zr,
When at least one of W is less than 0.2% by weight, the wettability is lowered, and the formation of carbon compounds of these metals is not promoted, so that the adhesion is lowered. In particular, T
In the case of i, Cr, Zr, and W, it is difficult to melt in Cu, and Ti, Cr, Zr, and W having low thermal conductivity are dispersed in Cu and / or on the Cu surface, and the heat of the optical semiconductor element 5 is reduced. It becomes difficult to efficiently transmit the inside of the mounting substrate 6.

The content of the metal component n in the metal-carbon composite A is preferably 10 to 20% by weight. If it is less than 10% by weight, the desired thermal conductivity cannot be obtained in the lateral direction, and if it exceeds 20% by weight, the difference in thermal expansion coefficient between the mounting substrate 6 and the optical semiconductor element 5 becomes large. Considering the difference in thermal expansion coefficient between the optical semiconductor element 5 and the mounting substrate 6, 15 to 20% by weight is more preferable. Further, by setting the content of the metal component n to 10 to 20% by weight, the ratio of the surface area of the metal component n appearing on the surface of the metal-carbon composite A is about 6 to the surface area of the metal-carbon composite A. 10%, which improves the adhesion strength of the metal plating layer b.

Regarding the coefficient of thermal expansion, when the metal component n is impregnated in the carbonaceous base material m at a suitable content of about 10 to 20% by weight, the coefficient of thermal expansion of the metal-carbon composite A becomes an optical semiconductor. It does not rise to the extent that it is significantly different from the element 5. In addition, particularly in the case of Ag among the metal components n, the thermal conductivity is very high, which is advantageous for transmitting heat of the optical semiconductor element 5.

Since the melting point of the metal component n is very high, the optical semiconductor package has a melting point of about 780.degree.
Even when assembled with a brazing material such as brazing, the metal component n does not melt, and the inside of the carbonaceous base material m can always be kept stable. The metal component n that melts during brazing
In the case of, it may flow out from the end surface of the mounting substrate 6,
It is not suitable as an optical semiconductor package.

The metal plating layer b deposited on the surface of the Cu layer Y comprises a Ni plating layer or a Cu plating layer. The thickness of the metal plating layer b is preferably 1 to 30 μm, and when it is less than 1 μm,
Due to the variation in the thickness, there may be a portion where the metal plating layer b is hardly deposited. If it exceeds 30 μm,
In the case of the Ni plating layer, the heat transfer efficiency is low and the heat of the optical semiconductor element 5 is not quickly dissipated. In the case of the Cu plating layer, the thermal expansion coefficient of the entire mounting substrate 6 is different from the thermal expansion coefficient of the substrate 1. In some cases, the bonding strength between the base 1 and the mounting substrate 6 deteriorates, and it becomes difficult to efficiently transfer the heat of the optical semiconductor element 5 to the base 1.

Further, the metal layer a effectively prevents He from being trapped in the pores of the unidirectional carbon fiber l when the airtightness of the inside of the optical semiconductor package is inspected using He, so that the airtightness is improved. An accurate judgment can be obtained for the sex test.

As described above, since the mounting substrate 6 has a structure in which a thin metal layer is bonded to the surface of the metal carbon composite A which is extremely lightweight, its specific gravity is much smaller than that of Cu-W alloy or the like. That is, since it is extremely lightweight, it is suitable for the recent weight reduction of optical semiconductor packages.

The shape of the main surface of the mounting substrate 6 is preferably similar to the main surface shape (rectangle or square) of the optical semiconductor element 5. In this case, heat is radiated isotropically around the optical semiconductor element 5. Further, from the viewpoint of a reinforcing plate that effectively prevents warpage of the base body 1 when screwing the base body 1, in order to balance the stress at the time of screwing, it is similar to the shape of the mounting portion 1a. It is preferable.

A substrate 1 is surrounded by such a mounting substrate 6.
On the upper surface of the frame body 2 joined to the upper surface, a lid 9 made of a metal such as Fe—Ni—Co alloy, Fe—Ni alloy, or ceramics such as Al ₂ O ₃ ceramics or AlN ceramics is Au—Sn solder or the like. And the optical semiconductor element 5 are hermetically sealed.

As described above, the optical semiconductor package of the present invention has a substantially rectangular metal base 1 having the mounting portion 1a on which the optical semiconductor element 5 is mounted via the mounting substrate 6.
And a fixing member mounting portion 3a that is joined to the upper surface of the base body 1 so as to surround the mounting portion 1a and has a through hole on one side, and an input / output terminal mounting portion that has a notch or a through hole on the other side. 7
a frame body 2 in which a is formed, a tubular fixing member 3 which is fitted to the fixing member attaching portion 3a or one end of which is joined to the periphery of the outer opening of the frame body 2 of the through hole, and the input / output terminal attaching And an input / output terminal 7 fitted to the portion 7a. The substrate 1 has a thickness of 0.1 to 0.5 mm, and the mounting substrate 6 is made of Ag, Ti, Cr, Zr in the carbonaceous base material m in which the aggregate of the unidirectional carbon fibers 1 is dispersed. And a metal-carbon composite A impregnated with a metal component n containing 0.2 to 10% by weight of at least one of W and W and 90 to 99.8% by weight of Cu, and the metal-carbon composite A were sequentially laminated on the upper and lower surfaces. It has a stainless steel layer X and a Cu layer Y, and a metal plating layer b deposited on the surface of the Cu layer Y.

The optical semiconductor package of the present invention, the optical semiconductor element 5 mounted and fixed on the mounting portion 1a and electrically connected to the input / output terminal 7, and the upper surface of the frame 2 are joined together. By including the lid body 9, an optical semiconductor device as a product is obtained. The optical fiber whose end is inserted into the fixing member 3 is generally provided when the optical semiconductor device is used, but it may be added to the optical semiconductor device as a single product, or the optical semiconductor device may be an external electric circuit. It may be attached when it is fixedly used on a substrate or the like.

Specifically, the optical semiconductor device has a mounting portion 1a.
The optical semiconductor element 5 is adhered and fixed on the mounting substrate 6 by means of an adhesive such as glass, resin or brazing material, and the electrode of the optical semiconductor element 5 is electrically connected to a predetermined metallized layer 7b through a bonding wire. After connecting, and thereafter, by joining the lid body 5 to the upper surface of the frame body 2 with a low melting point brazing material or the like,
The optical semiconductor device is a product in which the optical semiconductor element 5 is housed inside the optical semiconductor package including the base 1, the frame 2, the fixing member 3, the window 4, the mounting substrate 6, and the input / output terminal 7. In this optical semiconductor device, for example, the optical semiconductor element 5 is optically excited by a high-frequency signal supplied from an external electric circuit board, and the excited laser light or the like is transmitted to and received from the optical fiber through the window 4 and is transmitted in the optical fiber. Thus, it functions as a photoelectric conversion device capable of transmitting a large amount of information at high speed, and is used in the field of optical communication and the like.

[0058]

EXAMPLES Examples of the optical semiconductor package of the present invention will be described below.

Example 1 The optical semiconductor package shown in FIGS. 1 to 3 was manufactured by the following steps [1] to [4].

[1] Vertical length of about 13 mm x width of about 30 mm x thickness of 2.5
mm of Cu-W alloy is formed in a plan view shape of Fe-Ni-Co alloy of about 13 mm in length and about 21 mm in width so as to surround the mounting portion 1a on the outer peripheral portion of the upper main surface of the substantially rectangular base 1. The substantially rectangular frame 2 was joined with silver solder. In addition, screw holes 1b are formed at both ends on the short side of the substrate 1, and a Ni plating layer having a thickness of 3 μm and an Au plating layer having a thickness of 1.5 μm are formed on the surfaces of the substrate 1 and the frame body 2. I / O terminal mounting portions 7a are formed on the side portions of the frame body 2 facing each other, and a fixing member mounting portion 3a formed of a through hole is formed on one side portion adjacent to these side portions. ing.

[2] I / O terminals 7 made of alumina ceramics were fitted and joined to the I / O terminal mounting portions 7a on the opposite sides of the frame body 2 by silver brazing. The input / output terminal 7 is formed of Mo-Mn formed so as to conduct the inside and outside of the frame body 2.
A Ni plating layer having a thickness of 3 μm and an Au plating layer having a thickness of 1.5 μm were sequentially deposited on the metallized layer 7b. A lead terminal 8 made of an Fe—Ni—Co alloy was joined to the outside of the metallized layer 7b of the frame 2 with an Ag brazing material.

[3] A Ni plating layer with a thickness of 3 μm and a thickness of 3 μm on the fixing member mounting portion 3a consisting of a through hole on one side of the frame body 2.
Fe-Ni-C with 1.5 μm Au plating layer deposited in sequence
The cylindrical fixing member 3 made of o alloy is joined with silver solder,
A disk-shaped window 4 made of lead-based glass was joined to the inside of the fixing member 3 with an Au—Sn alloy brazing material via a W metallization layer.

[4] The mounting substrate 6 joined to the mounting portion 1a of the base 1 has a thickness of about 1.5 mm × length of about 5 mm × width of about 6 m.
m is a substantially rectangular parallelepiped, and 1% by weight of Ag and Cu are contained in the carbonaceous base material m in which the aggregate of the unidirectional carbon fibers 1 is dispersed.
Of the metal-carbon composite A impregnated with the metal component n containing 99% by weight, and the thickness of 5 μm, 10 μm, 30 μ on the upper and lower surfaces thereof.
m, 50 μm, 70 μm stainless steel layer X and thickness 20 μm, 50 μm, 100 μm, 150 μm, 200 μm, 300 μ
a metal layer a in which Cu layers Y of m and 400 μm are sequentially laminated,
It has a Cu plating layer b deposited on the surface of the Cu layer Y. Table 1 shows the results of measuring the thermal expansion coefficient and thermal conductivity in the lateral direction and the thermal expansion coefficient and thermal conductivity in the vertical direction for these mounting substrates 6. In addition, these mounting substrates 6 can be formed into various thicknesses (0.1 mm, 0.3 mm, 0.5 mm,
0.6 mm, 0.7 mm) is bonded to the upper surface of the base body 1 with tin (Sn) -lead (Pb) solder, and the optical semiconductor element 5 which is an LD is mounted and bonded on the mounting substrate 6 with an Au-Si brazing material. Together with the bonding wire, the metallized layer 7 of the input / output terminal 7
Table 1 shows the results of evaluation of the operability of the optical semiconductor element 5 with respect to each of the optical semiconductor packages which are connected to b and drive the optical semiconductor element 5. In Table 1, ◯ indicates that no abnormality has occurred in the optical semiconductor element 5, Δ indicates that the laser light oscillation state of the optical semiconductor element 5 has become unstable due to heat, and x indicates. Indicates that the optical semiconductor element 5 malfunctions due to heat, the oscillation of the laser light is stopped, or the optical semiconductor element 5 is peeled off from the mounting substrate 6.

[0064]

[Table 1]

From Table 1, when the thickness of the stainless steel layer X is 70 μm, the coefficient of thermal expansion is 11 × 10 ⁻⁶ / ° C. or more, that is, 7 × 10 ^−6, regardless of the thickness of the Cu layer Y. ~ 10 ×
It is out of the range of 10 ⁻⁶ / ° C., and a difference in thermal expansion with the metal-carbon composite A is likely to occur. Therefore, it was found that the thickness of the stainless steel layer X is preferably 50 μm or less. Further, it was found that the stainless steel layer X should preferably have a thickness of 5 μm or more in terms of production.

The thickness of the stainless steel layer X is 50
When the thickness of the Cu layer Y is 20 μm or 50 μm,
The horizontal thermal conductivity is lower than the vertical thermal conductivity,
It was found that it is difficult to dissipate the heat of the optical semiconductor element 5 to the outside in the lateral direction. On the other hand, when the thickness of the Cu layer Y exceeds 300 μm, the coefficient of thermal expansion becomes large outside the range of 7 × 10 ⁻⁶ to 10 × 10 ⁻⁶ / ° C., and a difference in thermal expansion with the metal-carbon composite A occurs. It became easier. Therefore, it was found that the thickness of the Cu layer Y is preferably 100 to 300 μm.

When the stainless steel layer X and the Cu layer Y were within the above ranges, it was found that the operability of the optical semiconductor element 5 was good when the thickness of the substrate 1 was 0.1 to 0.5 mm.

(Example 2) Further, the metal components n are Ti and C.
The thickness of the stainless steel layer X is 30 μm, and the thickness of the Cu layer Y is 150 μ, except for u and various contents.
Table 2 shows the results of measurement of the thermal expansion coefficient and thermal conductivity in the lateral direction of the mounting substrate 6 and the thermal expansion coefficient and thermal conductivity in the vertical direction when m is set. In addition, these mounting substrates 6 have various thicknesses (0.1 mm, 0.3 mm, 0.5 mm, 0.6 mm, 0.7 m).
m) is bonded to the upper surface of the base body 1 with Sn-Pb solder, the optical semiconductor element 5 which is an LD is mounted on the mounting substrate 6 with Au-Si brazing material, and the input / output terminals 7 are metallized with bonding wires. Table 2 shows the results of evaluating the operability of the optical semiconductor element 5 with respect to each of the optical semiconductor packages connected to the layer 7b and driving the optical semiconductor element 5.

[0069]

[Table 2]

From Table 2, the Ti contents are 0.05, 0.1 and 0.1.
In the case of 5, 15 and 20% by weight, the thermal conductivity is low in both the horizontal and vertical directions. That is, it was found that when the Ti content is out of the range of 0.2 to 10% by weight, it becomes difficult to dissipate the heat of the optical semiconductor element 5.

Then, the thickness of the stainless steel layer X is
30 μm, Cu layer Y thickness is 150 μm, and Ti is 0.2-10
When the weight ratio is within the range, the thickness of the substrate 1 is 0.1 to
It was found that the operability of the optical semiconductor element 5 was good when it was 0.5 mm.

In place of Ti, Cr, Zr or W
The same results as above were obtained when using.

(Example 3) Further, the thickness of the stainless steel layer X is 30 μm and the thickness of the Cu layer Y is 150 μm.
Is a metal-carbon composite A impregnated with 0.2, 0.5, 1, 10% by weight and a metal component n containing Cu as the remaining component, and the mounting substrate 6 is configured in the same manner as in Example 1 above. Table 3 shows the results of measuring the coefficient of thermal expansion and thermal conductivity in the horizontal direction and the coefficient of thermal expansion and thermal conductivity in the vertical direction. Also,
These mounting boards 6 can be made into various thicknesses (0.1 mm, 0.3 m
m, 0.5 mm, 0.6 mm, 0.7 mm) S on the upper surface of the substrate 1
The optical semiconductor element 5, which is an LD, is bonded by n-Pb solder, and the optical semiconductor element 5, which is an LD, is mounted and bonded on the mounting substrate 6 with an Au-Si brazing material, and the metallized layer 7 of the input / output terminal 7 is bonded with a bonding wire.
Table 3 shows the results of evaluation of the operability of the optical semiconductor element 5 with respect to each of the optical semiconductor packages which were connected to b and driven the optical semiconductor element 5.

[0074]

[Table 3]

From Table 3, it was found that the thermal conductivity increases with the addition amount of Ag as compared with the case of adding any one of Ti, Cr, Zr and W. Also,
It was found that the operability of the optical semiconductor element 5 may be impaired depending on the thickness of the substrate 1 even if the thermal conductivity is very high. That is, when the thickness of the substrate 1 exceeds 0.5 mm, the operability deteriorates.

The present invention is not limited to the above embodiments and examples, and various modifications can be made without departing from the scope of the present invention. For example, the optical semiconductor device may be provided with an optical isolator for preventing return light inside or outside, for example inside or outside the optical semiconductor package of the fixing member 3, or in the middle of the optical fiber outside the optical semiconductor package. In this case, the optical semiconductor element 5
The optical coupling efficiency between the optical fiber and the optical fiber is further improved.

[0077]

In the package for accommodating an optical semiconductor element of the present invention, the thickness of the substantially rectangular metal base having the mounting portion on the top surface of which the optical semiconductor element is mounted via the mounting substrate is 0.1.
Is 0.5 mm, and the mounting substrate is made of Ag, Ti, a carbonaceous base material in which an aggregate of unidirectional carbon fibers is dispersed.
0.2-10 at least one of Cr, Zr and W
%, And a metal-carbon composite impregnated with a metal component containing 90 to 99.8% by weight of Cu, a stainless steel layer and a copper layer sequentially laminated on the upper and lower surfaces of the metal-carbon composite, and the surface of the copper layer. The mounting substrate on which the optical semiconductor element is mounted has a high thermal conductivity not only in the plane direction but also in the thickness direction, and is dense and has no pores on the surface because it has the deposited metal plating layer. Therefore, the operability of the optical semiconductor element can be improved, and the airtightness inside the optical semiconductor package can be stably maintained.

The package for accommodating an optical semiconductor device of the present invention preferably has a thickness of the stainless steel layer of 5 to 50 μm.
m and the thickness of the Cu layer is 100 to 300 μm, the heat of the optical semiconductor element can be satisfactorily dissipated.

The optical semiconductor device of the present invention is formed by joining the optical semiconductor package of the present invention, the optical semiconductor element mounted and fixed on the mounting portion and electrically connected to the input / output terminal to the upper surface of the frame body. By including the lid, the optical semiconductor package of the present invention can be highly reliable.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an embodiment of a package for housing an optical semiconductor element of the present invention.

2 is a cross-sectional view of the package for storing an optical semiconductor element of FIG.

3 is a partial enlarged cross-sectional view of a mounting substrate in the package for storing an optical semiconductor element of FIG.

FIG. 4 is a perspective view of a conventional package for storing an optical semiconductor element.

5 is a cross-sectional view of the package for storing an optical semiconductor element of FIG.

[Explanation of symbols]

1: Base 1a: Placement part 2: Frame body 3: Optical fiber fixing member 3a: Optical fiber fixing member attachment part 5: Optical semiconductor element 6: Mounting board 7: Input / output terminal 7a: Input / output terminal mounting part A: Metal-carbon composite a: Metal layer b: Metal plating layer l: Unidirectional carbon fiber m: Carbonaceous base material n: Metal component X: Stainless steel layer Y: Copper layer

Continued front page    F term (reference) 5F073 AB28 FA07 FA14 FA15 FA16                       FA18 FA28 FA29

Claims (3)

[Claims] 1. A substantially rectangular metal base body having a mounting portion on which an optical semiconductor element is mounted via a mounting substrate, and a top surface of the base body joined to the mounting portion so as to surround the mounting portion. A frame body having an optical fiber fixing member attachment portion formed of a through hole on one side and an input / output terminal attachment portion formed of a notch or a through hole on the other side, and the optical fiber fixing member attachment portion. A tubular optical fiber fixing member that is fitted into the through hole or one end of which is joined to the circumference of the frame body outside opening of the through hole, and an input / output terminal fitted to the input / output terminal mounting portion. In the package for storing an optical semiconductor element comprising, the thickness of the base is 0.1 to 0.5 mm, the mounting substrate is a carbonaceous base material in which an aggregate of unidirectional carbon fibers is dispersed. Fewer of silver, titanium, chromium, zirconium and tungsten A metal-carbon composite impregnated with a metal component containing 0.2 to 10% by weight of at least one kind and 90 to 99.8% by weight of copper, and a stainless steel layer and a copper layer sequentially laminated on the upper and lower surfaces of the metal-carbon composite And a metal plating layer deposited on the surface of the copper layer. 2. The stainless steel layer has a thickness of 5-5.
The package for storing optical semiconductor elements according to claim 1, wherein the thickness of the copper layer is 0 μm and the thickness of the copper layer is 100 to 300 μm. 3. The package for storing an optical semiconductor element according to claim 1 or 2, an optical semiconductor element mounted and fixed on the mounting portion and electrically connected to the input / output terminal, An optical semiconductor device comprising: a lid joined to an upper surface of a frame.