JPH04352377A - Submount for semiconductor laser element - Google Patents

Abstract

PURPOSE:To prevent a die-bonded solder from coming into contact with a junction part including an active region and blocking off a laser beam when a J/D is assembled in order to obtain a low heat resistance and a low drooping characteristic. CONSTITUTION:The face of a submount 3, on which a semiconductor laser chip 1 is mounted, is formed to be recessed and protruding shapes. It is possible to prevent an excess solder from flowing to recessed parts in the submount, coming into contact with a junction part in the semiconductor laser chip and blocking off a laser beam.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submount for a semiconductor laser device, and more particularly to a submount for a semiconductor laser device that can prevent solder that protrudes during die bonding of a semiconductor laser device from having an adverse effect on laser operation.

0002

2. Description of the Related Art FIG. 2 is a perspective view showing a state in which a semiconductor laser chip is die-bonded using a conventional semiconductor laser element submount. In the figure, 1 is a laser chip, 2 is a submount, 4 is a metal block, 5 is solder, 6
, 7 are laser beams.

Next, the operation will be explained. As shown in FIG. 2, a laser chip 1 is generally bonded via a submount 2 to a metal block 4 with good heat dissipation. Solder 5 is used to fix the laser chip 1 to the submount 2. By applying a forward bias to the pn junction formed in the laser chip between electrodes (not shown) provided on the upper and lower surfaces of the laser chip 1, laser beams 6, 7 is emitted. The laser beam 7 emitted from the rear end surface is used as monitor light for controlling the output of the laser beam 6 emitted from the front end surface.

By the way, when semiconductor lasers are used in ODDs or printers, junction down (J/D) assembly is used, in which the light emitting region is assembled close to the submount 8, in order to obtain low thermal resistance and low droop characteristics. It is essential. In this case, since the light emitting region is located at a position approximately several micrometers from the adhesive, the solder 5 after die bonding poses a problem in assembly.

[0005]

[Problem to be Solved by the Invention] Since the conventional submount for semiconductor laser elements is constructed as described above,
The solder that protrudes upward from the surface of the submount 8 during die bonding may come into contact with the junction part of the light emitting area and cause a short circuit, or the laser beam 7 emitted from the rear end of the laser chip may be caused by the protruding solder. There is a problem in that a defect occurs in which the monitor current is small due to reflection in a different direction.

[0006] This invention was made in order to solve the above-mentioned problems, and it is possible to improve the yield without causing short-circuit defects or defects in reflection of laser light in different directions due to protruding solder during die bonding. The purpose is to obtain a highly reliable submount for a semiconductor laser device.

[0007]

[Means for Solving the Problems] A submount for a semiconductor laser device according to the present invention is such that at least the region of the submount on which a semiconductor laser chip is placed is formed into an uneven shape.

[0008]

[Operation] In the submount for a semiconductor laser device according to the present invention, at least the region on which the laser chip of the submount is mounted is formed with unevenness, so that the laser chip is die-bonded to the convex portion of the submount, and the laser chip is used when die-bonding. The solder flows out into the recessed portion of the submount, and the solder does not come into contact with the laser chip, especially the junction portion including the light emitting region.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a state in which a semiconductor laser chip is die-bonded using a semiconductor laser element submount according to an embodiment of the present invention. In the figure, 1 is a semiconductor laser chip, 3 is a submount of this embodiment, and the entire surface on which the semiconductor laser chip 1 is placed is formed into an uneven shape. Also, 4 is a metal block, 5 is solder, 6,
7 is a laser beam.

This embodiment is characterized in that the surface of the submount 3 on which the semiconductor laser chip 1 is placed has a shape having a plurality of projections and depressions. According to this embodiment,
Since the surface of the submount 3 on which the semiconductor laser chip 1 is placed is formed into an uneven shape, the semiconductor laser chip 1 is die-bonded to the convex part of the submount 3, and the solder 5 that protrudes when die-bonding is applied to the convex part. It flows into lower depressions and does not rise upwards. Therefore, even during J/D assembly to obtain low thermal resistance and low droop characteristics, the die-bonded solder does not come into contact with the junction part including the light emitting area of the laser chip 1, which prevents short circuit defects and laser It is possible to prevent small monitor current defects caused by light being reflected in different directions.

[0011] In the above embodiment, a submount is shown in which unevenness is provided over the entire surface on which the semiconductor laser chip 1 is placed, but the unevenness is provided only in the area where the semiconductor laser chip 1 is placed. In this case as well, the same effects as in the above embodiment can be achieved.

0012

As described above, according to the present invention, at least the semiconductor laser chip mounting area of the submount is formed in an uneven shape, so that the semiconductor laser chip is die-bonded to the convex portion and the solder at the time of die-bonding is reduced. flows into the recess, thereby preventing problems such as the protruding solder that comes into contact with the junction including the light emitting area during die bonding and causing a short circuit, or the laser light being reflected in a different direction and reducing the monitor current. This has the effect of improving yield and reliability.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a state in which a laser chip is die-bonded using a submount for a semiconductor laser device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which a laser chip is die-bonded using a conventional submount for a semiconductor laser element.

[Explanation of symbols]

1 Laser chip 2 Conventional submount 3 Submount according to an embodiment of the present invention 4 Metal block 5 Solder 6 Laser light 7 Laser light

Claims (1)

[Claims] 1. When a semiconductor laser chip is bonded to a metal block, in a semiconductor laser element submount disposed between the semiconductor laser chip and the metal block, at least an area on which the semiconductor laser chip is placed is A submount for a semiconductor laser element characterized by being formed in an uneven shape.