JP2001274498A - Package for housing optical semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package in which an optical semiconductor element is operated normally and stably for a long period by a method wherein a base which is composed of a metal and a lead terminal are bonded strongly via a sealing glass. SOLUTION: This optical semiconductor package is provided with lead terminals 3 ends on one side of which are inserted into through holes 1a in a container body 1 and which are bonded via the sealing glass 4. The sealing glass 4 is composed of a porous glass with a mean pore size of 3 to 15 μm and at a porosity of 3 to 7%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor device housing package for hermetically sealing and housing optical semiconductor devices such as LDs (semiconductor lasers) and PDs (photodiodes). The present invention relates to a method of melting lead glass and joining and fixing lead terminals.

[0002]

2. Description of the Related Art Conventionally, an optical semiconductor element housing package (hereinafter referred to as an optical semiconductor package) for fixing a lead terminal by melting a sealing glass as shown in FIGS. 1 (a), 1 (b) and 2 has been known. ) Is used. This optical semiconductor package is made of 50 alloy @ Fe50 wt (weight)%-N
a box-shaped container main body 1 made of a metal material such as i50 wt% alloy｝, and having an opening (recess) for forming a space for accommodating the optical semiconductor element 2 such as an LD or PD at a substantially central portion of the upper surface thereof; , 50 alloy, etc., and the container body 1
A cylindrical metal fixing member (hereinafter, referred to as a fixing member) in which an optical fiber is inserted and fixed from the outer end of the side wall, and a spherical lens member 6 is bonded to the inside through a sealing glass. , A fixing member) 5 and a lid 8 attached to the upper surface of the container body 1 and hermetically sealing the optical semiconductor element 2.

Further, a metal such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy for making an electrical connection between the optical semiconductor element 2 and an external electric circuit is provided on an outer surface of the container body 1. Terminal 3 made of
Glass 4 made of borosilicate glass etc.
Is welded through.

The outer surface of the container body 1 and the fixing member 5 is provided with a Ni plating layer and an Au plating layer in order to prevent oxidative corrosion and to improve the wettability of a brazing material for joining various parts. The cylindrical fixing member 5 is a through hole 1a of the container body 1.
Is attached with a low melting point brazing material such as an Au-Sn alloy brazing material.

[0005] The lead terminal 3 is joined to the base 1 by a through hole 1 having a diameter slightly larger than the width or diameter of the lead terminal 3.
In this case, one end of the lead terminal 3 is inserted into the through-hole 1b through the ring-shaped sealing glass 4, and then the sealing glass 4 is heated and melted to be solidified. The sealing glass 4 is made of borosilicate glass or the like and generally has a linear thermal expansion coefficient of about 9 × 10 ⁻⁶ / ° C., and its composition is boron oxide (B ₂ O ₃ ), silicon oxide (SiO ₂ ).
₂ ), zinc oxide (ZnO) and the like.

[0006]

However, in the above-mentioned conventional optical semiconductor package, since the borosilicate glass is used for joining the lead terminals 3 with the sealing glass 4, the lead made of the sealing glass 4 is used. When the terminals 3 were welded, the bonding strength between the lead terminals 3 made of metal and the base 1 was insufficient. Therefore, there has been a problem that the airtightness is broken at the joint of the lead terminal 3 with the sealing glass 4.

In order to improve the bonding strength when the metal members such as the lead terminals 3 are bonded with the sealing glass 4, the temperature of the sealing glass 4 at the time of heating and melting, that is, the melting point is set high. Therefore, it is necessary to improve the wettability with the metal member and to sufficiently form a bonding reaction layer.

However, in the conventional sealing glass 4 made of borosilicate glass, when the melting point is increased, the viscosity of the glass is greatly reduced, and the sealing glass 4 flows to the outside through the lead terminals 3 and the base 1 Insufficient sealing glass 4 at the joint between the lead terminal 3 and the lead terminal 3 creates a through hole there,
Improper airtightness occurred immediately after sealing.

Accordingly, the present invention has been completed in view of the above circumstances, and an object of the present invention is to make the bonding between the base 1 and the lead terminals 3 strong and to lengthen the optical semiconductor element housed inside the optical semiconductor package. That is, it can operate normally and stably over a period.

[0010]

According to the present invention, there is provided a package for housing an optical semiconductor device, comprising: a container body having an opening formed in an upper surface for housing the optical semiconductor device therein and having a plurality of through holes formed in side portions; A cylindrical metal fixing member that is inserted and fixed in one of the through holes and an optical fiber is inserted and fixed from the outer end of the side portion, a lens member that is inserted and fixed inside the metal fixing member, and the like. Is inserted through the through hole of
A lead terminal joined by filling the through-hole with a sealing glass having an average pore diameter of 3 to 15 μm and a porosity of 3 to 7%, and the optical semiconductor element attached to an upper surface of the container body; And a lid that hermetically seals the lid.

According to the present invention, a large number of the above-described structures exist inside the sealing glass even when the heating and melting temperature at the time of joining the base and the lead terminal with the sealing glass is high (about 900 ° C.). The viscosity of the sealing glass does not significantly decrease due to the fine bubbles, and as a result, the sealing glass does not flow to the outside through the lead terminal, and the glass at the junction between the base and the lead terminal runs short. The problem that a through hole is formed there is eliminated. In addition, by increasing the heating and melting temperature when joining the base and the lead terminal with the sealing glass, the wettability between the metal member and the sealing glass is improved, and the bonding reaction layer is sufficiently formed. It is possible to firmly join the base made of metal and the lead terminal via the glass for sealing, and to operate the optical semiconductor element housed in the optical semiconductor package normally and stably for a long period of time. Can be.

In the present invention, preferably, the arithmetic average roughness of the inner surface of the through-hole and the surface of the joint of the lead terminal joined by the through-hole is 0.3 to 10 respectively.
μm. This further increases the bonding strength of the sealing glass.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical semiconductor package according to the present invention will be described below. The basic configuration of the entire optical semiconductor package of the present invention is the same as that shown in FIGS. 1 and 2 and is made of a metal material such as 50 alloy, Fe--Ni--Co alloy, and LD, PD, etc. A box-shaped container main body 1 having an opening (recess) for forming a space for accommodating the optical semiconductor element 2 and a metal member such as a 50 alloy, an Fe—Ni—Co alloy, and a side wall of the container main body 1 A cylindrical fixing member 5 into which an optical fiber is inserted and fixed from the outer end of the side wall, and a spherical lens member 6 is bonded inside via a sealing glass;
And a lid 8 hermetically sealing the optical semiconductor element 2.

An outer surface of the container main body 1 is provided with an optical semiconductor device 2 and an electric circuit for external connection.
One end of a lead terminal 3 made of a metal such as an alloy 0, an Fe—Ni—Co alloy is inserted into the through hole 1b and welded through a sealing glass 4 made of a borosilicate glass or the like.
The one end of the lead terminal 3 is connected to an electrode of the optical semiconductor element 2 via a bonding wire or the like. The cross-sectional shape of the lead terminal 3 can be various shapes such as a rectangular shape as shown in FIG. 1, a polygonal shape, a circular shape, and an elliptical shape.

The container body 1 and the fixing member 5 have a Ni plating layer having a thickness of about 2 to 5 μm and a thickness of about 2 to 5 μm in order to prevent oxidative corrosion on the outer surface and to improve the wettability of a brazing material for joining each part. Au plating layers of 1 μm or more are sequentially applied. The cylindrical fixing member 5 is attached to the inside of the through hole 1a of the container body 1 with a low melting point metal brazing material such as an Au-Sn alloy brazing material.

The lead terminal 3 is joined to the base 1 by a through hole 1 having a diameter slightly larger than the width or diameter of the lead terminal 3.
In this case, one end of the lead terminal 3 is inserted into the through hole 1b through the ring-shaped sealing glass 4, and then the sealing glass 4 is heated and melted to be solidified. In FIG. 2, the package means an optical semiconductor package.

In order for the base 1 and the lead terminal 3 of the present invention to be firmly bonded, the arithmetic average roughness of each of the inner surface of the through hole 1b and the surface of the joint of the lead terminal 3 is 0.3. -10 μm, preferably 0.3 μm
If it is less than μm, the molten sealing glass 4 spreads too much and the wettability deteriorates due to the smooth surface, so that a meniscus is hardly formed. As a result, the bonding strength decreases. If the arithmetic average roughness exceeds 10 μm, the unevenness of the surface becomes large, and the strengths of the base 1 and the lead terminals 3 tend to decrease.

In order to roughen the surface of the joint between the base 1 and the lead terminal 3 (roughness) as described above, it is preferable to form an oxide layer having a thickness of about 1 to 5 μm on the surface of the joint. . If the thickness is less than 1 μm, the oxide layer is too thin, so that the reaction layer with the sealing glass 4 becomes thin, so that strong bonding cannot be performed. If it exceeds 5 μm, an oxide layer having a low strength remains in the reaction layer, and the strength of the reaction layer itself decreases.

The oxide layer on the surface of the joint between the substrate 1 and the lead terminal 3 is formed in an oxidizing atmosphere at 500 to 600 ° C.
It can be formed by a method of performing a heat treatment in advance for about 20 minutes.

In the present invention, the container body 1 is not limited to an integrally formed box-shaped one as shown in FIG. 1, but a plate-shaped base (bottom plate) and an optical semiconductor element 2 provided on the peripheral edge of the upper surface of the base. And a frame joined so as to surround the frame. As the lens member, in addition to the spherical lens member 6, various members such as a hemispherical lens member, an aspherical lens member, and a rod-shaped lens member can be used.

In the present invention, the lead terminal 3 is connected to the base 1.
The porous sealing glass 4 to be bonded to the through hole 1a is manufactured as follows. A powder such as borosilicate glass having an average particle size of 2 to 5 μm (maximum particle size of about 70 μm) is mixed with an appropriate organic resin binder, a solvent, and the like, granulated, filled into a mold so as to form a ring, and pressed. It is molded to produce a molded body. After the molded body is calcined at 500 to 600 ° C. to remove the organic resin binder component, a ring-shaped sealing glass 4 is inserted into the through hole 1 a of the base 1, and the lead terminal 3 is inserted into the center hole. Insert and insert one end. Next, 900
By heating and melting the sealing glass 4 at a temperature of about 0 ° C., the sealing glass 4 has an average pore diameter of about 3 to 15 μm and a porosity (a void area ratio in the sealing glass 4) of 3 to 7%. The result is a porous sealing glass 4.

When the average pore diameter of the sealing glass 4 is less than 3 μm, the fluidity of the sealing glass 4 at a high temperature (about 900 ° C.) becomes high, that is, the viscosity of the glass decreases and the penetration of the base 1 It becomes difficult to hermetically seal the joint between the hole 1a and the lead terminal 3. On the other hand, if it exceeds 15 μm, the strength of the sealing glass 4 decreases, and the reliability of hermetic sealing decreases.

If the porosity of the sealing glass 4 is less than 3%,
The fluidity of the sealing glass 4 at a high temperature (about 900 ° C.) increases, that is, the viscosity of the glass decreases, and it is difficult to hermetically seal the joint between the through hole 1 a of the base 1 and the lead terminal 3. Become. On the other hand, if it exceeds 7%, the strength of the sealing glass 4 decreases, and the reliability of hermetic sealing decreases.

The above average pore diameter and porosity can be specified by observing a cross-sectional photograph of the sealing glass 4 after welding and actually measuring it.

The thickness (height) d (FIG. 2) of the sealing glass 4 in the vertical direction is determined by the size of the optical semiconductor package,
Although it depends on the structure, it is preferably about 0.1 to 1.0 mm.
If it is less than 1 mm, the fluidity of the sealing glass 4 is reduced, the welding is insufficient, and the bonding strength is reduced. If it exceeds 1.0 mm, the mechanical strength of the joint tends to decrease.

The sealing glass 4 of the present invention is made of borosilicate glass (softening point: about 700 ° C.). In the case of borosilicate glass, its composition and composition range are silicon oxide (SiO ₂ ).
55 to 65 wt%, boron oxide and (B ₂ O ₃₎ 18~28
% By weight, 4 to 10% by weight of sodium oxide, 2 to 8% by weight of aluminum oxide, 1 to 6% by weight of potassium oxide,
Lithium oxide 1-6 wt%, barium oxide 0.5-
It contains 3% by weight.

The reason for setting the above composition range is as follows. If the silicon oxide content is less than 55% by weight, the chemical resistance of the sealing glass 4 deteriorates, and the reliability of hermetic sealing decreases. If the silicon oxide content exceeds 65% by weight, the softening and melting temperature of the sealing glass 4 increases, and the oxidation of the metal member proceeds in the assembling process, thereby lowering the product strength.

When the content of boron oxide is less than 18% by weight, the softening and melting temperature of the sealing glass 4 becomes high, and the oxidation of the metal member proceeds in the assembling process, thereby lowering the product strength. Boron oxide is 2
When the content exceeds 8% by weight, the chemical resistance of the sealing glass 4 is deteriorated, and the reliability of hermetic sealing is reduced.

If the content of sodium oxide is less than 4% by weight, the softening and melting temperature of the sealing glass 4 becomes high, and the oxidation of the metal member proceeds in the assembling process, and the product strength decreases. If the content of sodium oxide exceeds 10% by weight, the chemical resistance of the glass for sealing 4 deteriorates, and the reliability of hermetic sealing decreases.

If the content of aluminum oxide is less than 2% by weight, the chemical resistance of the sealing glass 4 is deteriorated, and the reliability of hermetic sealing is reduced. If the aluminum oxide content exceeds 8% by weight, the softening and melting temperature of the sealing glass 4 increases, and the oxidation of the metal member proceeds in the assembling process, resulting in a reduction in product strength.

When the content of potassium oxide is less than 1% by weight, the softening and melting temperature of the sealing glass 4 becomes high, and the oxidation of the metal member proceeds in the assembling process, thereby lowering the product strength. If the content of potassium oxide exceeds 6% by weight, the chemical resistance of the sealing glass 4 deteriorates, and the reliability of hermetic sealing decreases.

When the content of lithium oxide is less than 1% by weight, the softening and melting temperature of the sealing glass 4 becomes high, and the oxidation of the metal member proceeds in the assembling process, thereby lowering the product strength. If the lithium oxide content exceeds 6% by weight, the chemical resistance of the sealing glass 4 deteriorates, and the reliability of hermetic sealing decreases.

When the barium oxide content is less than 0.5% by weight, the softening and melting temperature of the sealing glass 4 becomes high, and the oxidation of the metal member proceeds in the assembling process, thereby lowering the product strength. If the content of barium oxide exceeds 3% by weight, the chemical resistance of the sealing glass 4 deteriorates, and the reliability of hermetic sealing decreases.

Further, the sealing glass 4 may be other than the borosilicate glass, but the glass containing lead oxide (PbO) may be made of Ni plating layer after the lead terminal 3 is bonded, Au
Glass that does not contain lead oxide is preferable because the properties such as solder wettability of the plating layer deteriorate.

Thus, according to the present invention, even if the melting temperature of the sealing glass is set to a high temperature (about 900 ° C.), the viscosity of the sealing glass is greatly reduced due to a large number of fine bubbles inside the sealing glass. The result is that the sealing glass does not flow outside through the lead terminals,
This eliminates the problem that the glass at the joint between the base and the lead terminal is insufficient and a through hole is formed there. In addition, by increasing the heat melting temperature of the sealing glass, the wettability between the metal member and the sealing glass can be improved, and the bonding reaction layer can be sufficiently formed. Can be firmly joined via the sealing glass, and the optical semiconductor element can be normally and stably operated for a long period of time.

In the present invention, the bonding reaction layer between the metal member and the sealing glass is preferably formed with a thickness of 1 μm or more from the surface of the metal member, and if it is less than 1 μm, the bonding strength is deteriorated.

The present invention is not limited to the above-described embodiment, and various changes may be made without departing from the scope of the present invention.

[0038]

According to the present invention, there is provided an optical semiconductor package having a lead terminal, one end of which is inserted into a through hole of a container body and which is joined via a glass for sealing.
The porous glass having an average pore diameter of 3 to 15 μm and a porosity of 3 to 7% allows a large number of particles to be formed inside the sealing glass even when the heating and melting temperature of the sealing glass is high (about 900 ° C.). The viscosity of the sealing glass does not significantly decrease due to the fine bubbles that are present, and as a result, the sealing glass does not flow to the outside through the lead terminal, and the glass at the joint between the base and the lead terminal is reduced. The problem of shortage and the formation of a through hole there is eliminated. In addition, by increasing the heat melting temperature of the sealing glass, the wettability between the metal member and the sealing glass can be improved, and the bonding reaction layer can be sufficiently formed. Can be firmly joined via the sealing glass, and the optical semiconductor element can be normally and stably operated for a long period of time.

Further, the present invention preferably further provides a sealing device in which the arithmetic average roughness of each of the inner surface of the through-hole and the surface of the joint of the lead terminal joined by the through-hole is 0.3 to 10 μm. The bonding strength of the glass for use increases.

[Brief description of the drawings]

1A and 1B show an optical semiconductor package of the present invention, wherein FIG. 1A is a perspective view of the optical semiconductor package, and FIG. 1B is a cross-sectional view of the optical semiconductor package.

FIG. 2 is a cross-sectional view of a joint of a lead terminal according to the present invention.

[Explanation of symbols]

 1: container body 2: optical semiconductor element 3: lead terminal 4: sealing glass 5: fixing member 6: spherical lens member 8: lid

Claims (2)

[Claims] 1. A container body having an opening formed in an upper surface and accommodating an optical semiconductor element therein and having a plurality of through-holes formed in a side portion, and being inserted and fixed in one of the through-holes, and being outside the side portion. A cylindrical metal fixing member into which an optical fiber is inserted and fixed from the end, a lens member inserted and fixed inside the metal fixing member, and the other through-hole, which has an average pore diameter of 3 to 15 μm A lead terminal joined by filling the through-hole with sealing glass having a porosity of 3 to 7%, and a lid attached to an upper surface of the container body and hermetically sealing the optical semiconductor element. And a package for housing an optical semiconductor element. 2. The arithmetic mean roughness of each of an inner surface of said through hole and a surface of a joint of said lead terminal joined by said through hole is 0.3 to 10 μm. Package for storing optical semiconductor elements.