JPH02235384A - Semiconductor light emitting device - Google Patents

Abstract

PURPOSE:To contrive miniaturization and improvement in reliability by forming a protrusion after surrounding a place at which a block for radiation of heat is installed at the mainface of a stem. CONSTITUTION:A protrusion 10 is mounted so that the protrusion may surround a block 2 for radiation of heat that is soldered at the center of the main face of a stem 1; besides, it may hold a position inside of the welded part of a cap 7. The protrusion 10 prevents a surplus soldering flux from flowing out up to the welded part of the cap 7 on the occasion of soldering the block 2 to the stem 1. As the protrusion 10 prevents effectively the soldering flux from spreading over surroundings, both stem 1 and cap 7 diameters can be reduced and then this device is miniaturized. Further, concentration of the surplus soldering flux into the surroundings of the block 2 renders close contact strength between the block 2 and the stem 1 more secure and then high reliability is obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the structure of a semiconductor light emitting device.

(Prior art) Figures 2 and 3 show conventional semiconductor light emitting devices, which are used as light sources for optical pickups in optical disk devices.
FIG. 2 is a cross-sectional view showing a laser diode device in which a photodiode for monitoring laser light is incorporated into the same stem. In the figure, (1) is a stem made of metal, (2)
is a heat dissipation block made of a metal with good thermal conductivity brazed to the center of the main surface (}. surface of the stem (1), and (3) is a heat dissipation block made of a metal with good heat conductivity) via the side K submount (4) of the heat dissipation block 12). The OLD chip (3), which is a Leb diode chip (hereinafter referred to as an LD chip) fixed in place, emits laser light (5) from its upper and lower ends, the operation of which will be described next. The laser beam (5) directed downward is fixed to the stem (1) and detected by nine monitor photodiodes (6), and the light intensity is monitored. On the other hand, a metal cap (7) is welded to the main direction (upper surface) of the ST411 by Iy welding, and the upper part of this cap (7) is opened, and this opening is made of transparent glass. The LD chip (3) is blocked by the plate (8).
; is hermetically sealed. Also, the stem (1) has 3 to 4
A book lead (9) is insulated as required and fixed through the wire, and the end of the lead is connected to a monitor photodiode (6) using a wire (not shown). LD chip (3)
are connected to the electrode portions of each to enable electrical operation. Here, the difference between the conventional devices shown in FIG. 2 and FIG. 3 lies in the shape of the stem 11), and in the device shown in FIG.
7) is provided on the stem (1). The device of FIG. 3 does not have this step, and the shape of the stem il+ is simplified.

The device shown in Fig. 3 requires some mechanical ingenuity to guide the needle to the device that welds the cap (7), but compared to the device shown in Fig. 2, it is manufactured at a lower cost due to its simpler stem shape. There are advantages that can be achieved.

[The problem that the invention seeks to solve]

In the conventional device shown in Fig. 3, the part where the heat dissipation block is brazed and the part where the cap is welded are on the same plane. The problem is that it spreads too much and reaches the welded part of the cap, making it impossible to weld the cap or impairing the airtightness of the welded part. This is a serious problem, especially when downsizing the device by reducing the diameter of the stem or cap. This had the problem of limiting the amount of information available.

This invention was made to solve the above-mentioned problems, and has a relatively simple shape that prevents the spread of the brazing material from reaching the soluble part of the cap when brazing the block onto the stem. The object of the present invention is to obtain a semiconductor light emitting (laser diode) device that can be easily miniaturized and inexpensive.

[Steps to solve n problems]

In the semiconductor light emitting device according to the present invention, a convex portion is provided on the inside of the ring-shaped welded portion of the cap, surrounding the area where the heat dissipation block is brazed on the crown surface of the stem.

[Effect]

In this invention, the convex portion provided surrounding the area where the heat dissipation block is brazed on the main surface (upper surface) 1 of the stem prevents excess brazing material from spreading to the surrounding area when the heat dissipation block is brazed. This prevents the brazing metal from adhering to the solder joint of the cap.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is a stem made of Kanagawa, (2) is a heat dissipation block made of a metal with good thermal conductivity brazed to the center of the crown (upper surface) of stem (1), and (3) is a heat dissipation block. This is a laser diode chip (hereinafter referred to as an LD chip) fixed to the side surface of the storage block {2} via a submount (4). This LD chip (3) emits laser light (5) from its upper and lower ends. Laser light directed downward (
5) is detected by a monitor photodiode (6) fixed to the stem tl). On the other hand, on the main surface side of the stem (1), a metal cap (7) is welded by Grozier-Equation welding, and the upper part of the cap (7) is open.
This opening is closed with a transparent glass plate (8), and the LD chip (3) is hermetically sealed. In addition, three to four leads (9) are insulated as necessary and fixed through the stem ll), and the lead ends are connected to the monitor photodiode +61. The fact that it is connected to the electrode part of the LD chip (3) to enable electrical operation is shown in Figure 2. Same as shown in Figure 3. However, in the device shown in the first diagram, the stem t1)
A convex portion 0 is provided on the main direction (upper surface) of the cap, surrounding the heat dissipation block (2) brazed to the center and located inside the circular welded portion of the cap (7). There is. This convex portion <II has a heat dissipation block 12 in the center of the stem {υ
》Excess filler metal cap generated when brazing (
7) to prevent it from spreading or flowing out toward the welding area, and preventing the brazing metal from adhering to the welding area and making it impossible to weld the cap (7), or even if it is possible, the airtightness will be compromised. It can be effectively prevented. In addition, this protrusion (11) only needs to have a sufficient effect of preventing the spread of the brazing material, and if the amount of brazing material is selected appropriately, a low one is sufficient, and the protrusion (11)
) can be easily and inexpensively formed into -IEi[i.

As a result, in order to effectively prevent the brazing material from spreading around the convex portion, it was possible to reduce the diameter of the stem (l) and cap (7) to make the device more compact. There is a young fruit that solves the difficulty caused by the expansion of the brazing filler metal for the blocks and allows for a more compact device. Since the brazing filler metal is concentrated around the heat dissipation block (2) due to the backflow, the adhesion strength between the heat dissipation block (2) and the stem (1) can be strengthened.

In the above embodiment, a laser diode device has been described, but it is obvious that other semiconductor light emitting devices having the same structure can produce the same effects as the above embodiment.

〔Effect of the invention〕

As described above, according to the present invention, since the convex part is formed surrounding the part where the heat dissipation block is attached to the main curve of the stem, the spread of excess brazing material to the cap # contact part when the block is attached is prevented.
In addition, excess filler metal flows back at the convex part and concentrates around the block, so the adhesion strength between the stem and block is strong. 9. It is smaller and more reliable. Effective in obtaining high quality semiconductor light emitting devices at low cost0

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a semiconductor light emitting device according to an embodiment of the present invention, and FIGS. 2 and 3 are sectional views showing a conventional laser diode device. In the figure, (l) is the stem, (2) is the heat dissipation block, (3) is the laser diode chip, (4) is the submount, (5} is the laser beam, (6) is the monitor photodiode, (7) is the cap, (8) is the glass plate, (9)
indicates the lead, and the symbol indicates a convex portion provided on the main surface of the stem 11). In addition, in the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A light-emitting element that emits light above the main surface is indirectly fixed to the main surface of the stem via a block, and a cap is welded to the stem so as to cover the light-emitting element, and the cap is The semiconductor light emitting device has an opening in the center, and the opening is covered with a transparent glass plate bonded to a cap, and the stem has a convex portion on its main surface surrounding a portion where the block is attached. A semiconductor light emitting device characterized by: