JPH10148736A - Package for optical communications - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the junction reliability of a lens holder for optical communication package. SOLUTION: A cavity 33 is formed for mounting a semiconductor element 32 for optical communications, in a ceramic package main body 31, and also on the side face of this package main body 31, a through-hole 39 is formed communicating with the cavity, and a kovar weldring 41 is sealingly connected with Ag-brazing material to an outer circumferential edge of the through-hole of an outer wall of this package main body 31. On the other hand, a lens 45 to be opposed to a tip of an optical fiber 44 led from outside is sealingly connected into a lens holder 43 of metal such as Fe-Ni alloy, etc., with glass 46 of a low melting point, and also this lens holder 43 is inserted into the weldring 41 and the through-hole 39, and all around the periphery of a brim part 43a of this lens holder 43 is pressure-welded onto a projection 47 formed all around the periphery of the weldring 41 for projection welding of the both.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication package having a built-in lens which faces an end of an optical fiber.

[0002]

2. Description of the Related Art A conventional general optical communication package includes:
As shown in FIG. 5, a ceramic package body 11 is formed.
A cavity 13 for mounting a semiconductor element 12 such as a laser diode (LD) or a light emitting diode (PD) for optical communication is formed therein, and a through hole 14 communicating with the cavity 13 is formed on a side surface of the package body 11. The package body 11 is formed by brazing a metal pipe 15 to the outer peripheral portion of the through hole 14 on the outer surface of the package body 11 with an Ag brazing material. In this optical communication package, an optical fiber 17 having a lens 16 attached to the tip is inserted into a cavity 13 through a through hole 14 through a pipe 15 so that the lens 16 faces the semiconductor element 12 and the pipe 15
The inside is sealed with a sealing material (not shown) for use.

[0003]

However, the above conventional optical communication package has a drawback that only the optical fiber 17 with the lens 16 can be used, and a general optical fiber without the lens 16 cannot be used.

In order to solve this drawback, as shown in FIG. 6, a seal ring 18 is brazed to the outer peripheral portion of the through hole 14 on the outer surface of the package body 11 with an Ag brazing material.
A lens 21 for facing the distal end of the optical fiber 20 is joined to the inside of a metal lens holder 19 formed in a flanged cylindrical shape, and the lens holder 19 is inserted into the seal ring 18 and the through hole 14. And the lens holder 1
A structure in which the entire periphery of the flange 9 is joined to the seal ring 18 with solder or Au-Sn has been considered.

This optical communication package has a cavity 1
Since the cavity 3 is used in a state in which the cavity 3 is sealed by sealing the cavity 3 with a cap (not shown), it is necessary to secure a sufficient sealing property also at the joint portion of the lens holder 19. The present inventor conducted an environmental test (temperature cycle test, thermal shock test) to confirm the sealing property of the optical communication package. The occurrence rate was high, and it was found that there was a problem in the joining reliability of the joining portion of the lens holder 19.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide an optical communication package capable of improving the joining reliability of a joining portion of a lens holder. .

[0007]

According to a first aspect of the present invention, there is provided an optical communication package having a weld ring on an outer peripheral portion of a through hole in an outer surface of a ceramic package body. The lens holder is joined, a metal lens holder is inserted into the weld ring and the through hole, and the entire periphery of the flange of the lens holder is resistance welded to the weld ring. Thus, the entire circumference of the flange portion of the lens holder is firmly welded to the weld ring, and cracks do not occur in the joint portion of the lens holder even in an environmental test. Also,
Resistance welding is a method in which the lens holder and the weld ring, which are the materials to be welded, are welded by applying a short period of time to the electrodes and pressurizing them with an electrode to generate resistance heat, so that welding speed is high and productivity is good. There are also advantages.

In this case, it is preferable to form an annular projection on the entire circumference of one of the welding surface of the flange portion and the weld ring of the lens holder and perform projection welding. By doing so, the resistance heat is limited to only the protruding portion, welding is performed efficiently with low power consumption, the temperature rise in the portion other than the protruding portion is small, and the effect of welding heat on other joints and the like is prevented. Can come off.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
4 through FIG. First, the configuration of the entire optical communication package will be described with reference to FIGS. The package body 31 made of ceramic is manufactured by laminating and firing ceramic green sheets such as alumina. Inside the package body 31, a laser diode (LD) for optical communication and a light emitting diode (PD) are provided. A cavity 33 for mounting a semiconductor element 32 such as the above is formed.

The cavity 33 of the package body 31
A conductor pattern 34 (see FIG. 2) for connecting the semiconductor element 32 by wire bonding or the like
On the two opposing side surfaces of the package body 31, a conductor pattern 35 that is electrically connected to the conductor pattern 34 in the cavity 33 is formed of W, Mo, or the like. It is joined with an Ag brazing material or the like.

A metallizing pattern 37 for sealing is formed on the upper surface of the package body 31 by W, Mo, or the like, and a sealing ring 38 made of metal such as Kovar is hermetically sealed on the metalizing pattern 37 for sealing with an Ag brazing material or the like. Is joined to. After the semiconductor element 32 is mounted in the cavity 33, a metal cap (not shown) is joined to the seal ring 38 by seam welding or the like, thereby sealing the cavity 33.

The lead frame 36 of the package body 31
A through-hole 39 communicating with the cavity 33 is formed on the side surface where is not joined, and a metallization pattern 40 for sealing is formed on the side surface with W, Mo, or the like. The weld ring 41 made of the above-mentioned metal is hermetically joined with an Ag brazing material or the like.

On the other hand, the lens holder 43 is made of, for example, Fe-
An optical fiber 44 formed from a metal such as a Ni alloy and having a flange portion 43a with a flange portion 43a therein.
The lens 45 for facing the tip of the low melting glass 4
6 is hermetically bonded. This lens holder 43 is
The entire circumference of the flange 43a of the lens holder 43 is inserted into the weld ring 41 and the through hole 39.
1 is resistance welded.

In this embodiment, an annular projection 47 is formed on the entire circumference of the welding surface of the weld ring 41,
Projection welding in which resistance welding is performed while pressing the flange 43a of the lens holder 43 against the lens 7 is employed. As shown in FIG. 3, the protrusion 47 has a triangular rib shape and the top is formed on a flat surface, the height H of the protrusion 47 is, for example, 0.1 to 0.2 mm, and the lateral width W of the top flat surface is, for example, 0.
02 to 0.03 mm, and the included angle θ on both sides is, for example, 50 to 7
It is set to 0 °.

Next, the procedure for assembling the lens holder 43 to the package body 31 will be described. Package body 31
The weld ring 41 is joined to the sealing metallization pattern 40 on the side surface with an Ag brazing material. Next, the welding surface of the weld ring 41 is plated with Ni or Au. Thereafter, using a projection welding apparatus, as shown in FIG. 4, one electrode 51 holds the weld ring 41 from the outer peripheral direction, and inserts the lens holder 43 into the weld ring 41, thereby forming the flange of the lens holder 43. The part 43 a is brought into contact with the projection 47 of the weld ring 41, and the other electrode 52 of the projection welding device is pressed against the flange 43 a of the lens holder 43. In this state, a voltage of about 100 V is applied, for example, for one second between the electrodes 51 and 52 in a state where the projection 47 of the weld ring 41 and the flange 43 a of the lens holder 43 are pressed against each other with a pressing force of about 100 kgf. And the projection 47 of the weld ring 41 and the lens holder 4
A high current is caused to flow between the third flange 43a and the protrusion 47 to cause the protrusion 47 to generate resistance heat, and the heat fuses the two.

In this manner, when the lens holder 43 is subjected to projection welding (resistance welding) to the weld ring 41, the entire periphery of the flange 43a of the lens holder 43 can be firmly joined to the weld ring 41. Therefore, even when an environmental test (a temperature cycle test or a thermal shock test) is performed, no crack is generated at the joint of the lens holder 43, and
Leakage does not occur, and the joining reliability of the joining portion of the lens holder 43 can be improved.

Further, when projections 47 are formed on the welding surface of the weld ring 41 and projection welding is performed as in the above embodiment, the resistance heat is limited to only the projections 47, and the projections 47 can be formed with less power consumption. The welding can be efficiently performed by efficiently generating heat, the temperature rise in portions other than the protrusions 47 can be reduced, and other joints (such as a brazing portion and a sealing portion made of the low-melting glass 46) are protected from welding heat. From this aspect, the reliability of the optical communication package can be improved.

Although the projection 47 for projection welding is formed on the welding surface of the weld ring 41 in the above embodiment, it may be formed on the welding surface of the flange 43a of the lens holder 43.

[0019]

As is apparent from the above description, according to the first aspect of the present invention, since the entire periphery of the flange of the lens holder is resistance-welded to the weld ring, the joint strength of the joint of the lens holder is obtained. And the joining reliability can be improved.

Further, in the second aspect, an annular projection is formed on the entire circumference of one of the welding surface of the flange portion and the weld ring of the lens holder, and projection welding is performed. Thus, highly reliable welding can be performed efficiently while suppressing the effect of welding heat on the workpiece.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a partially broken optical communication package.

FIG. 3 is an enlarged sectional view showing the shape of a welding projection of a weld ring.

FIG. 4 is a cross-sectional view of the vicinity of a weld for explaining a projection welding process.

FIG. 5 is a vertical sectional front view of an optical communication package showing a conventional example.

FIG. 6 is a longitudinal sectional front view of an optical communication package showing a comparative example.

[Explanation of symbols]

31: package body, 32: semiconductor element, 33: cavity, 36: lead frame, 38: seal ring,
39: through hole, 40: metallized pattern for sealing, 4
DESCRIPTION OF SYMBOLS 1 ... Weld ring, 43 ... Lens holder, 43a ... Flange part, 44 ... Optical fiber, 45 ... Lens, 46 ... Low melting point glass, 47 ... Projection.

Claims (2)

[Claims] 1. A cavity for mounting a semiconductor element for optical communication is formed inside a ceramic package body, and a through hole communicating with the cavity is formed on a side surface of the package body. A lens for joining a weld ring to an outer peripheral portion of the through hole on the outer side surface, and facing a tip of an optical fiber introduced from the outside into a metal lens holder formed in a flanged cylindrical shape. Wherein the lens holder is inserted into the weld ring and the through hole, and the entire periphery of the flange of the lens holder is resistance welded to the weld ring. 2. The optical communication package according to claim 1, wherein an annular projection is formed on the entire periphery of one of the welding surface of the flange portion of the lens holder and the weld ring.