JP2001237482A - Package for housing optical semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow no gap between a coaxial connector provided in a through- hole on the sidewall of an optical package and a coaxial cable connected to the coaxial connector from outside, so that the problem of poor connection with the outer-peripheral conductor of the coaxial cable is dissolved for reduced transmission loss of high-frequency signal, resulting in smooth propagation. SOLUTION: A sealing material insertion 2b, whose diameter expands toward the outside surface of a sidewall 2, is provided to the outside surface of the sidewall 2 of a through-hole 2a. A conductive elastic member 10 is so provided in the sealing material insertion 2b, as to be almost flush with the outside surface of the sidewall 2 and the end of a coaxial connector 3.

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 housing an optical semiconductor device such as an LD (semiconductor laser) and a PD (photodiode).

[0002]

2. Description of the Related Art FIG. 6 shows a conventional optical semiconductor device housing package (hereinafter referred to as an optical package) for housing optical semiconductor devices such as LDs and PDs. As shown in the figure, the optical package is made of a metal such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy (Kovar) or a copper (Cu) -tungsten (W) alloy. And a base 21 made of metal or the like having a mounting portion 21a on which the optical semiconductor element 24 is mounted, and a base 21 surrounding the mounting portion 21a.
The upper peripheral part is joined via a brazing material such as silver brazing,
And a frame 22 made of a metal such as a Ni-Co alloy.

The frame body 22 is formed of a ceramic such as alumina (Al ₂ O ₃ ) ceramic which is fitted in a through hole or a notch formed in a side portion thereof and provided with a plurality of lead terminals for external connection. The input / output terminal 25 is inserted into the through-hole 22a formed on the other side, and is connected to the light-transmitting member 28a for condensing light and the light for transmitting and receiving an optical signal between the optical semiconductor element 24 and the outside. Fe with the fiber 29 fixed
-A cylindrical fixing member 28 made of a metal such as a Ni-Co alloy
And are attached. A lid 31 made of an Fe-Ni-Co alloy or the like for hermetically sealing the optical semiconductor element 24 is provided on the upper surface of the frame 22 via a seal ring 32 made of an Fe-Ni-Co alloy or the like. Joined by welding or the like.

Reference numeral 23 denotes an electronic cooling element such as a Peltier element for cooling the optical semiconductor element 24 during driving, and reference numeral 30 denotes a bonding wire for connecting the optical semiconductor element 24 and the input / output terminal 25.

In such an optical package, in recent years, the operating frequency of the optical semiconductor element 24 has been further increased to about 10 to 40 GHz or more, and an external electric circuit to which the optical semiconductor element 24 is electrically connected. As a wiring conductor of a substrate, a coaxial cable which can continuously obtain a constant characteristic impedance and is excellent in the shielding property (electromagnetic shielding property) of an external electromagnetic wave has been used.

Therefore, the optical package is also electrically connected to the wiring conductor of the external electric circuit board in order to facilitate electrical connection with the coaxial cable used for the wiring conductor of the external electric circuit board. The present applicant has proposed an input / output terminal 25 having a coaxial connector instead of a conventional ceramic input / output terminal (conventional example 1: see Japanese Patent Application Laid-Open No. 9-64219).

In a package for housing a semiconductor element having a coaxial connector (hereinafter referred to as a semiconductor package), a semiconductor element is mounted on a mounting portion provided at the center of the upper surface of a bottom plate.
It is mounted and fixed on a circuit board on which a wiring conductor electrically connected to the electrode via a bonding wire is formed. As shown in FIG. 7, the semiconductor package provided with the coaxial connector has a through hole 42a in which a coaxial connector 43 is inserted and fixed in a part of a side wall 42, and a coaxial hole is formed in the through hole 42a. The connector 43 is inserted, and the connector 43 and the inner peripheral surface of the through hole 42a are joined via a sealing material 41 such as solder.

Further, a through hole 42a formed in the side wall 42
Has a sealing material insertion portion 42b whose diameter is spread stepwise over the entire circumference toward the outer surface, and the sealing material insertion portion 42b inserts the coaxial connector 43 into the through hole 42a. At the time of insertion and fixing through the through hole 41, a solder material serving as a sealing material 41 for fixing the inner wall of the through hole 42 a and the coaxial connector 43 is applied to the entire circumference of the gap between the inner wall of the through hole 42 a and the coaxial connector 43. Hold along. Therefore, if the solder material is heated and melted, the inner wall of the through hole 42a and the coaxial connector 4
3 is filled with the sealing material 41 over the entire circumference of the gap, and the inside and outside of the side wall 42a are completely airtightly partitioned.

The coaxial connector 43 is made of Fe-Ni-
At the center of a cylindrical outer conductor 44 made of a metal such as a Co alloy, a rod-shaped center conductor 46 also made of a metal such as an Fe-Ni-Co alloy is fixed via a glass member 45. The conductor 46 is electrically connected to a wiring conductor on a circuit board via solder.

[0010]

However, in the semiconductor package provided with the sealing material insertion portion 42b of the prior art example 1, the coaxial connector 43 is inserted into the through hole 42a provided in the side wall 42, and the sealing is performed. A ring-shaped solder material serving as the sealing material 41 is inserted and held in the material insertion portion 42b, and then the solder material is heated and melted to form a coaxial connector 43.
Is fixed, the ring-shaped solder material inserted into the sealing material insertion portion 42b moves to the gap between the inner wall of the through hole 42a and the coaxial connector 43, so that the outer surface of the side wall 42 surrounds the coaxial connector 43. The sealing material insertion portion 42b remains as a step.

As described above, when there is a step due to the sealing material insertion portion 42b around the coaxial connector 43 on the outer surface of the side wall 42, the inner diameter of the outer conductor of the external coaxial cable connected to the connector 43 is reduced. When the outer diameter of the outer conductor 44 is larger than the outer diameter of the outer conductor 44, when the coaxial connector 43 is connected to an external coaxial cable, the inner peripheral surface of the outer conductor of the coaxial cable is located at the step. When a high-frequency signal is propagated between the coaxial cable and the coaxial connector 43 connected in this manner, the high-frequency signal is caused by a skin effect and the surface of the central conductor of the coaxial connector 43 and the coaxial cable and the corresponding outer conductor Trying to flow in the vicinity of the inner peripheral surface.

However, since the inner peripheral surface of the outer conductor of the coaxial cable is located at the stepped portion of the side wall 42 due to the sealing material insertion portion 42b, the signal flowing through the coaxial connector 43 and the outer conductor of the coaxial cable is not transmitted. As a result, a phase difference occurs between the signal flowing through the central conductor of the coaxial connector 43 and the coaxial cable and the signal flowing through the outer peripheral conductor. As a result, the signal is attenuated or reflected, resulting in a problem that the signal cannot be efficiently propagated.

[0013] In order to solve such a problem, the present applicant has proposed that a through hole provided in a side wall has a sealing material insertion portion whose diameter increases stepwise or in a tapered shape toward the outer surface side of the side wall. And a conductive elastic member having a continuous surface having substantially the same height (substantially flush) as the end portion of the coaxial connector and the outer surface of the side wall is attached to the sealing material insertion portion. Example 2: See JP-A-11-186427).
However, in the conventional example 2, since the conductive elastic member is mounted after the sealing material is formed, it is necessary to make the height variation of the sealing material parallel to the side wall of the conductive elastic member. The consequences are disturbing. Also, the surfaces of the conductive elastic member and the coaxial connector are not constant, and when the coaxial cable is inserted, a gap is generated between the coaxial connector and the coaxial cable. As a result, the dielectric constant of the transmission line changes and the high-frequency signal As a result, transmission loss occurs and the characteristics are degraded.

Accordingly, the present invention has been completed in view of the above problems, and an object of the present invention is to provide an optical package that can transmit a high-frequency signal smoothly with a reduced transmission loss.

[0015]

According to the present invention, there is provided an optical semiconductor device housing package having a bottom plate having a mounting portion on which an optical semiconductor device is mounted on an upper surface, and the mounting portion being surrounded by an outer peripheral portion of the upper surface of the bottom plate. A coaxial connector which is inserted into a through hole provided in the side wall so as to be substantially flush with an outer surface of the side wall, and which is joined by a sealing material; A sealing member that is joined to the upper surface of the through hole and hermetically seals the optical semiconductor element, and a sealing material insertion portion whose diameter increases toward the outer surface of the side wall at the outer surface of the side wall of the through hole. In addition, a conductive elastic member is provided in the sealing material insertion portion so as to be substantially flush with the outer surface of the side wall and the end of the coaxial connector.

According to the present invention, since a conductive elastic member having conductivity and elastically deformable is provided in the sealing material insertion portion according to the above configuration, a coaxial cable externally connected to a coaxial connector is provided. The entire circumference of the end of the outer conductor for grounding (earth) is connected almost uniformly without leakage through the conductive elastic member, so that no gap is formed between the coaxial connector and the coaxial cable. The connection failure of the outer conductor is eliminated. As a result, the dielectric constant does not change due to the gap in the transmission line of the high-frequency signal, so that the transmission loss of the high-frequency signal is reduced and the high-frequency signal can be smoothly propagated.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The optical package of the present invention will be described in detail below. FIG. 1 is a sectional view showing an example of an embodiment of an optical package according to the present invention, and FIG. 2 is an enlarged sectional view of a main part (coaxial connector part). The connector 4 is a lid.

The bottom plate 1 of the present invention is made of iron (Fe) -nickel.
(Ni) -cobalt (Co) alloy or copper (Cu) -tang
Substantially square plate made of metal such as stainless (W) alloy
The optical semiconductor such as LD, PD, etc.
A mounting portion 1a for mounting an element is formed.
An optical semiconductor element 5 is provided on the mounting portion 1a, for example, alumina (Al).
_TwoO_Three) Mounted on a circuit board 6 made of high-quality ceramics
It is mounted and fixed in the state.

The electrodes of the optical semiconductor element 5 mounted on the circuit board 6 are electrically connected to metallized wiring conductors 6a formed on the circuit board 6 via bonding wires 7 and the like. .

A mounting portion 1a is provided on the outer peripheral portion of the upper surface of the bottom plate 1.
, A frame-shaped side wall 2 is erected so as to surround the optical semiconductor element 5 together with the bottom plate 1.
To form a space to accommodate

The side wall 2 is made of Fe—Ni, similarly to the bottom plate 1.
-It is made of a metal such as a Co alloy or a Cu-W alloy and is formed integrally with the bottom plate 1 or brazed to the bottom plate 1 through a brazing material such as silver brazing, or by a welding method such as a seam welding method. It is erected on the outer peripheral portion of the upper surface of the bottom plate 1 by welding.

A through hole 2a into which the coaxial connector 3 is inserted and fixed is formed in a part of the side wall 2.
a, the outer peripheral surface of the coaxial connector 3 and the inner peripheral surface of the through hole 2a opposed thereto are formed of solder. It is fixed via a sealing material 8.

Further, a through hole 2a formed in the side wall 2 is provided.
Has a sealing material insertion portion 2 b on the outer surface side of the side wall 2, the diameter of which expands stepwise over the entire circumference toward the outer surface of the side wall 2. When the coaxial connector 3 is inserted and fixed in the through hole 2a via the sealing material 8, the sealing material insertion portion 2b is used for sealing between the inner peripheral surface of the through hole 2a and the coaxial connector 3. It functions to hold the ring-shaped solder material serving as the material 8. Further, the sealing material insertion portion 2b can take various shapes, such as a shape in which the diameter of the through-hole 2a is stepped toward the outer surface of the side wall 2, or a shape in which the diameter gradually widens, such as an inverted taper shape.

The through hole 2a formed in the side wall 2 has a sealing material insertion portion 2b whose diameter is stepwise spread over the entire circumference toward the outer surface of the side wall 2, so that the through hole 2a is formed in the through hole 2a. And a sealing material 8 for joining the inner peripheral surface of the through hole 2a and the outer peripheral surface of the coaxial connector 3 facing the inner peripheral surface of the through hole 2a into the sealing material insertion portion 2b.
When the ring-shaped solder material is inserted and held and the solder material is heated and melted, the gap between the inner peripheral surface of the through hole 2a and the outer peripheral surface of the coaxial connector 3 is filled with the sealing material 8 over the entire circumference. Will be done.

The coaxial connector 3 inserted and fixed in the through hole 2a of the side wall 2 electrically connects the optical semiconductor element 5 housed therein to an external coaxial cable 9,
-Cylindrical outer conductor 3 made of metal such as Ni-Co alloy
A central conductor 3b, which is also made of a metal such as an Fe-Ni-Co alloy, is fixed to a central portion of a through a sealing glass member 3c.

In the coaxial connector 3, the outer conductor 3a is electrically connected to the side wall 2 via the sealing material 8 and the center conductor 3b is electrically connected to the wiring conductor 6a of the circuit board 6 via a conductive adhesive such as solder. It is connected to the.

The sealing material insertion portion 2b of the through hole 2a of the side wall 2 has a continuous surface almost flush with the end of the coaxial connector and the outer surface of the side wall. A ring-shaped conductive elastic member 10 made of a material and imparted with conductivity by means of containing conductive fine particles or the like is provided between the outer surface of the side wall 2 formed by the sealing material insertion portion 2b and the coaxial connector 3. It is attached via a sealing material 8 such as solder so as to fill a step between the ends. Alternatively, the conductive elastic member 10 made of a thermosetting resin or the like flows into the sealing material insertion portion 2b as a fluid, and
It is formed by heating and curing at a temperature of 0 ° C.

The conductive elastic member 10 preferably has an electric resistivity of 1 × 10 ⁻³ Ωm or less, preferably 1 × 1 ⁻³ Ωm or less.
If it exceeds 0 ^-3 Ωm, the shielding (electromagnetic shielding) effect of the high-frequency signal tends to be deteriorated, and the propagation of the high-frequency signal is hindered. When conductive fine particles or the like are contained for imparting conductivity, Ag, Au, Pt, Pd, C
u, Al, Fe, Sn, In, W, Mo, Mn, Ni,
Cr, Ti, Zn, Ru, Rh, Zr, Cu-Zn, S
It can be performed by incorporating conductive fine particles made of a highly conductive element and material such as US (stainless steel).

The average particle size of these conductive fine particles is 0.1.
When the thickness is less than 0.01 μm, the conductive fine particles are likely to be aggregated or unevenly distributed, so that it is difficult to uniformly impart conductivity to the entire conductive elastic member 10. If it exceeds 10 μm, the properties of the conductive fine particles as a solid are strongly affected, and the elasticity of the conductive elastic member 10 tends to be hindered.

The content of the conductive fine particles in the conductive elastic member 10 is preferably 3 to 50% by weight, and if the content is less than 3% by weight, the electrical resistivity of the conductive elastic member 10 becomes large and the shielding effect is deteriorated. , 50% by weight, the elasticity of the conductive elastic member 10 is hindered.

Further, when the coaxial cable 9 is pressed or crimped to the coaxial connector 3 from the outside, the conductive elastic member 10 elastically deforms the conductive elastic member 10 so that the coaxial connector 3 and the coaxial cable 9 are connected to each other. is intended to prevent the gap is formed between, the impact resilience is preferably at least 30%, is less than 30%, since the elastic deformation is insufficient, the coaxial cable 9 from the outside 15 kg / cm ² about normal When the coaxial connector 3 is crimped by an external force, a gap of about 0.1 mm between the coaxial connector 3 and the coaxial cable 9 does not disappear and remains. The rebound resilience is 80%
The following is preferable, and if it exceeds this, the conductive elastic member 10 becomes gel-like and easily slips out of the compression direction, and as a result, enters the gap between the coaxial connector 3 and the coaxial cable 9 to generate a high frequency signal (RF signal) terminal. Center conductor 3 as
b and the outer peripheral conductor 3a as a ground conductor are electrically short-circuited (short-circuited).

Further, the width of the ring-shaped conductive elastic member 10 is preferably 0.1 mm or more, and the thickness is preferably about 0.1 to 1.0 mm. If the width is less than 0.1 mm, it is manufactured by a press molding method or the like. In this case, it is difficult to accurately define the shape.
If the thickness is less than 0.1 mm, the conductive elastic member 10
Has a small elastic deformation width, and the characteristics of the elastic body deteriorate. If the thickness exceeds 1.0 mm, the conductive path between the outer conductor 3a and the outer conductor 9a of the coaxial cable 9 becomes longer, and the electrical resistance of the conductive elastic member 10 tends to increase. The conductive action between the conductor 3a and the outer conductor 9a and the shielding properties are likely to deteriorate.

Since the conductive elastic member 10 is elastically deformed, it may protrude to some extent from the outer surface of the side wall 2 as shown in FIG. 4, and the protruding length is preferably more than 0 mm and 0.5 mm or less. . When the protruding length exceeds 0.5 mm, when the coaxial cable 9 is crimped to the coaxial connector 3, the compression width due to the elastic deformation of the conductive elastic member 10 tends to be smaller than the protruding length, and the coaxial cable 9 and the coaxial connector 3 are compressed. Is easily formed between them.

According to the optical package of the present invention, the ring-shaped conductive elastic member 1 filling the step between the outer surface of the side wall 2 and the end of the coaxial connector 3 in the sealing material insertion portion 2b.
Since 0 is attached, no step is formed around the end of the coaxial connector 3 on the side wall 2. Further, even when a step is generated between the end of the coaxial connector 3 and the end of the ring-shaped conductive elastic member 10, the conductive elastic member 1
The formation of a step can be suppressed by the elastic deformation of zero.

Therefore, even when the inner diameter of the outer conductor 9a of the external coaxial cable 9 connected to the coaxial connector 3 is larger than the outer diameter of the outer conductor 3a of the coaxial connector 3,
Outer conductors 3a of the coaxial connector 3 and the coaxial cable 9;
The high-frequency signal flowing near the inner peripheral surface of the sealing material insertion portion 2a
It does not flow around the step formed by b.
Further, even when the coaxial connector 3 protrudes from the outer surface of the side wall 2, the coaxial cable 9 can be in close contact with the coaxial connector 3 by using the conductive elastic member 10 of the present invention. High-frequency signals can be efficiently propagated between them.

The coaxial connector 3 is connected to the through hole 2 in the side wall 2.
a, the coaxial connector 3 is inserted into the through hole 2a of the side wall 2 so that its end is substantially flush with the outer surface of the side wall 2, and the through hole 2a is fixed. For example, a ring-shaped solder material and a ring-shaped conductive elastic member 10 serving as the sealing material 8 are inserted into the sealing material insertion portion 2b.
Is inserted so as to surround the end of the solder material, and then the solder material is heated and melted once, and then cooled and solidified. As a result, the molten ring-shaped solder material was
The sealing material 8 is filled over the entire circumference of the gap between the inner peripheral surface a and the outer peripheral surface of the coaxial connector 3 to form the sealing material 8, whereby the inside and outside airtightness of the side wall 2 is not impaired at all.

In the present invention, the frequency band of the high-frequency signal for driving the optical semiconductor element 5 is not particularly limited, but is a high-frequency band of about 1 to 100 GHz and a super-high-frequency band. , Especially about 10 to 40 GHz.

Thus, according to the optical package of the present invention, the optical semiconductor element 5 is mounted and fixed on the circuit board 6 having the wiring conductor 6a electrically connected to its electrode on the mounting portion 1a of the bottom plate 1. Thereafter, the wiring conductor 6a of the circuit board 6 and the center conductor 3b of the coaxial connector 3 are electrically connected to each other via solder.
Bonding the lid 4 made of a metal such as a Ni-Co alloy by a soldering method or a seam welding method to form an optical semiconductor device as a product, and connecting the coaxial connector 3 to an external coaxial cable 9; As a result, the optical semiconductor element 5 housed inside is electrically connected to an external electric circuit.

It should be noted that 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. For example, in the example of the above-described embodiment, the step-like sealing material insertion portion 2b is provided in the through hole 2a formed in the side wall 2, but as shown in the cross-sectional view of FIG. The sealing material insertion portion 2b may be used. Further, a through hole, a notch, or the like is formed on a side of the side wall 2 other than the side where the coaxial connector 3 is provided, and a cylindrical fixing member for fixing an optical fiber and an input / output terminal are fitted. May be.

[0040]

According to the present invention, a sealing material insertion portion whose diameter is widened toward the outer surface of the side wall is provided on the outer surface of the side wall of the through-hole, and the outer surface of the side wall and the end of the coaxial connector are substantially formed within the sealing material insertion portion. By providing the conductive elastic member so as to be flush, the entire circumference of the end of the grounding outer peripheral conductor of the coaxial cable connected from the outside to the coaxial connector is almost completely leaked through the conductive elastic member. It will be connected uniformly,
There is no gap between the coaxial connector and the coaxial cable, and the poor connection of the outer conductor of the coaxial cable is eliminated. As a result, the dielectric constant does not change due to the gap in the transmission line of the high-frequency signal, so that the transmission loss of the high-frequency signal is reduced and the high-frequency signal can be smoothly propagated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an optical package of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the optical package of FIG.

FIG. 3 shows another embodiment of the optical package of the present invention;
It is a principal part expanded sectional view.

FIG. 4 shows another embodiment of the optical package of the present invention;
It is a principal part expanded sectional view.

FIG. 5 is an enlarged sectional view of a main part of a conventional optical package.

FIG. 6 is a sectional view showing an example of a conventional optical package.

FIG. 7 is an enlarged sectional view of a main part of the optical package of FIG. 6;

[Explanation of symbols]

 1: bottom plate 1a: mounting portion 2: side wall 2a: through hole 2b: sealing material insertion portion 3: coaxial connector 4: lid 5: optical semiconductor element 9: coaxial cable

Claims (1)

[Claims] 1. A bottom plate having a mounting portion on which an optical semiconductor element is mounted on an upper surface, a frame-shaped side wall provided on an outer peripheral portion of the upper surface of the bottom plate so as to surround the mounting portion, and provided on the side wall. A coaxial connector, the end of which is inserted into the through hole so as to be substantially flush with the outer surface of the side wall and is joined by a sealing material, and the optical semiconductor element is joined to the upper surface of the side wall to hermetically seal the optical semiconductor element And a sealing material insertion portion whose diameter increases toward the outer surface of the side wall is provided on the outer surface side of the side wall of the through hole, and the outer surface of the side wall and the inner surface of the sealing material insertion portion are provided. A package for storing an optical semiconductor element, wherein a conductive elastic member is provided so as to be substantially flush with an end of a coaxial connector.