JPH09148622A - Semiconductor ld module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mount a light-receiving element using a wireless bonding method in an optical fiber module, having a light-emitting element and a light-receiving element which mounts the light-emitting element, with which the light-receiving element and an optical fiber are optically connected. SOLUTION: A semiconductor LD element (LD) 5 and a light receiving element (PD) 6, to be used for output monitoring of the semiconductor LD element 5, are provided in a package, and terminals 7, which are led out to outside from inside the package are provided. At this time, the edge face of the package is non-parallelly inclined against the edge face of the LD 5, and an insulated substrate 13 is engaged to the terminal 7 and attached to the above-mentioned inclined surface. A metallized pattern, which is used to electrically connect the PD 6 and the terminal 7, is formed on the substrate 13. The PD 6 is flip chip bonded corresponding to the above-mentioned pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor LD module for optically coupling a semiconductor LD element and an optical fiber. In particular, it relates to a module in which a light receiving element for monitoring the output of a semiconductor LD element can be easily mounted.

[0002]

2. Description of the Related Art As a conventional semiconductor LD module, there is one described in JP-A-5-67844. In this module, a semiconductor LD element, a light receiving element and the like are mounted on a base in a package, a light extraction window is provided on one wall surface of the package, and a lens and an optical fiber are fixed to the outside. Light from the semiconductor LD element passes through the light extraction window,
It is efficiently incident on the optical fiber through the lens.

By the way, in the above module, noise is increased when the incident surface of the light receiving element is parallel to the end surface of the semiconductor LD element, so that the two are made non-parallel. The light receiving element and the terminal are connected by wire bonding, but if the light receiving element is arranged non-parallel to the semiconductor LD element, this connection work becomes difficult. Therefore, the light receiving element is mounted on the block in advance, and this block is attached at an angle at a position facing the semiconductor LD element. The connection between the light receiving element and the terminal has been performed by connecting the block and the terminal by wire bonding.

[0004]

However, it is troublesome to align the light receiving element with the semiconductor LD element in the above module. Moreover, since a block for mounting the light receiving element is required, the number of parts increases. Furthermore, there is a problem that the mounting process is complicated because wire bonding is performed for connection with the terminal.

[0005]

The present invention has been made to solve the above problems, and is characterized in that one inner surface of a package is formed as an inclined surface that is not parallel to a semiconductor LD element, and The light receiving element was flip-chip bonded through the substrate. Here, a metallized pattern for electrically connecting the light receiving element and the terminal is formed on the substrate. Further, it is preferable to form a solder portion on the back surface of the insulating substrate, that is, the surface where the substrate contacts the inclined surface and the portion where the terminal of the metallized pattern contacts. In particular, if the insulating substrate is provided with a groove that engages with the terminal in the package and the metallized pattern is also formed in this groove, the substrate and the terminal can be easily aligned.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on specific examples. FIG. 1 shows a module of the present invention.
(A) is a plan view with the lid removed, and (B) is a side view. This module consists of bottom plate 1, side face 2, end faces 3A, 3B
The LD 5 (semiconductor LD element) and the PD 6 (light receiving element) are mounted in a package constituted by the lid 4 (see FIG. B). The LD 5 emits an optical signal in response to the electric signal sent through the terminal 7, and the signal is extracted to the outside through a window 8 provided on the one end face 3A of the package facing the LD 5.

A lens 9 and an optical fiber 10 are fixed to the outer surface of the end surface 3A. The lens 9 makes the optical signal passing through the window 8 efficiently enter the optical fiber 10. Optical fiber 10
Is inserted into ferrule 11 and this ferrule 11 is sheath
The sheath 12 is inserted into the package 12, and the sheath 12 is further fixed to the package end surface 3A. The optical fiber is obliquely cut at the end face of the ferrule into which the optical fiber is inserted. On the other hand, the PD 6 detects an output change of the LD 5 due to temperature deterioration and the like, and controls the output of the LD 5 by feedback. The PD 6 is attached to a rear position facing the LD 5, that is, to the other end surface 3B of the package via an insulating substrate 13. For the insulating substrate 13, ceramics such as alumina or aluminum nitride, glass, or the like is used. Here, the inside of the other end surface 3B of the package for fixing the insulating substrate 13 was tilted with respect to the end surface of the LD 5. That is, the one end surface 3A provided with the window 8 and the other end surface 3B (inclined surface) to which the substrate 13 is fixed are configured to be non-parallel. Two holes are provided on the other end surface 3B, and a terminal 7 having a circular cross section is fixed to the hole with a glass sealing material.

The structure of the insulating substrate 13 fixed to this inclined surface is shown in FIG. As shown in the figure, it has a substantially square shape, and a metallized pattern 14 (hatched portion) is formed on the surface. This pattern is for flip-chip bonding the PD 6 on the insulating substrate 13, and is formed in a pattern corresponding to the electrodes on the PD mounting surface. In this example, Ti / Pt
Using / Au as a metallized material, patterning was performed by photolithography. Then, bumps 14A and 14B (cross hatching portions) were formed by soldering on the flip chip mounting surface with the PD. An example of the upper surface of the PD mounted on this mounting surface is shown in FIG. The shaded area in the figure is the area where the metallization pattern is applied. When this PD 6 is mounted on the insulating substrate 13, the PD 6 corresponds to the portion surrounded by the broken line in FIG. 2A, and the metallized portions 15A and 15B of the PD 6 are respectively attached to the solder bumps 14A and 14B in FIG. 2A. Correspond. In addition, a groove 17 having a semicircular cross section that engages with the terminal 7 is formed at the opposite position on the side surface of the substrate (see FIG. 2B).
The groove 17 serves as a guide when the substrate 13 is attached to the inclined surface.
In this example, the metallized pattern 14 on the surface of the substrate was formed so as to be continuous with the surface of the groove 17. Therefore, if the groove 17 is engaged with the terminal 7 and the substrate 13 is attached to the inclined surface, the PD 6 on the substrate to the terminal 7 are electrically connected through the metallized pattern 14. Further, a solder portion (not shown) was formed on the back surface of the substrate (the surface in contact with the inclined surface) and the surface of the groove 17. By this solder portion, the back surface of the substrate and the inclined surface, the terminal 7 and the metallized pattern 14 of the groove are joined. The mounting position of the substrate 13 is determined by the engagement between the groove 17 and the terminal 7, and the position of the PD 6 is determined by the metallization pattern on the substrate.
Determined by the correspondence with 14. Therefore, the metallized pattern 14 may be designed so that the PD mounting position is located just behind the LD 5 when the substrate 13 is attached to the inclined surface.

In mounting the PD 6, first, the PD 6 is flip-chip bonded so as to correspond to the metallized pattern 14 of the substrate 13. Next, the board 13 is soldered to the inclined surface with the groove 17 corresponding to the terminal 7. At this time, the surface of the groove 17 and the terminal 7 are also soldered. As a result, the substrate 13 and the inclined surface as well as the terminal 7 and the groove 17 can be soldered by one heat treatment, and these can be fixed and electrically connected at the same time. The substrate 13
The terminals 7 and the grooves 17 may be soldered after soldering to the inclined surface. By flip-chip bonding the PD 6 to the substrate 13 in this manner, the PD 6 can be easily installed non-parallel to the end surface of the LD 5. At that time, mounting by wireless bonding becomes possible. In particular, since the board 13 can be accurately positioned on the inclined surface by providing the groove 17 that engages with the terminal 7, the PD 6 can be easily aligned with the LD 5.

The other structure of this module is as follows. The number of terminals 7 was six. Two are for LD, the other two are for PD, and the remaining two are spares for incorporating a driver IC and an optical modulator (not shown). A glass seal 18 is provided between each terminal 7 and the package. Also, LD
Mounted components such as 5 are connected to the terminals 7 by gold wire bonds 19.

[0011]

As described above, according to the module of the present invention, the PD can be mounted by wireless bonding, and the mounting process can be simplified and the mounting cost can be reduced. Further, by providing a groove for engaging the terminal on the insulating substrate on which the light receiving element is mounted, the substrate can be accurately fixed in the package, and the PD can be easily positioned.

[Brief description of the drawings]

FIG. 1 shows a module of the present invention, (A) is a plan view with a lid removed, and (B) is a side view.

FIG. 2 shows a metallized pattern of an insulating substrate,
(A) is a plan view of the substrate, (B) is a side view of the substrate.

FIG. 3 is a plan view showing an upper surface of a light receiving element.

[Explanation of symbols]

1 Bottom plate 2 Side surface 3A One end surface 3B Other end surface 4 Lid part 5 LD 6 PD 7 Terminal 8 Window 9 Lens 10 Optical fiber 11 Ferrule 12 Sheath 13 Insulating substrate 14, 15A, 15B Metallized pattern 14A, 14B Solder bump 17 Groove 18 Glass seal Stop 19
Wire bond

Claims (3)

[Claims] 1. A semiconductor LD module in which a semiconductor LD element and a light receiving element for monitoring the output of the semiconductor LD element are built in a package and which has a terminal drawn out from the package to optically connect the semiconductor LD element and an optical fiber. The one inner surface of the package is inclined non-parallel to the end surface of the semiconductor LD element, and an insulating substrate is mounted on the inclined surface in contact with the terminal, and the substrate includes the light receiving element and the terminal. A semiconductor LD module, in which a metallized pattern for electrical connection with is formed, and a light receiving element is flip-chip bonded corresponding to this pattern. 2. The semiconductor LD module according to claim 1, wherein a solder portion is formed on the back surface of the insulating substrate and at a portion in contact with the terminal of the metallized pattern. 3. The semiconductor LD module according to claim 1, wherein a groove engaging with a terminal in the package is provided in the insulating substrate, and the metallized pattern is continuous with the groove.