JP2003163410A - Method of coating end face of semiconductor laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of coating end face of semiconductor laser which does not result in the fear for generation of flaws and cracks, by improving workability and reducing mechanical stress to be applied on a semiconductor laser bar during the work to isolate the semiconductor laser bar and spacer after the coating of an optical thin film at the end surface of semiconductor laser bar. <P>SOLUTION: In the method of coating the end face of a semiconductor laser wherein a spacer 101 is inserted between the semiconductor laser bars 1, the predetermined optical thin film is formed between the light emitting surface 2a and the rear surface of light emitting surface. Thereafter, the semiconductor laser bar 101 is isolated from the spacer 101, a groove 102 which is opened to the external side is provided to the spacer 101 under the condition that the spacer 101, and semiconductor laser bar 1 are set in contact with each other. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an optical thin film on an end surface (a light emitting surface and a light emitting rear surface) of a semiconductor laser by alternately arranging semiconductor laser bars and spacers, and particularly, after forming the optical thin film. And a method for coating an end face of a semiconductor laser, which facilitates the work of separating the semiconductor laser bar from the spacer.

[0002]

2. Description of the Related Art In a semiconductor laser, it is generally practiced to form an optical thin film on the end face in order to protect the light emitting face from oxidation and to control the reflectance. Normally, this is a semiconductor laser bar in which semiconductor laser elements are arranged in a row, and is formed by vapor deposition or sputtering.
At this time, when the semiconductor laser bars are directly stacked and arranged,
There is a problem that a uniform optical thin film is not formed on the end surface of the lower semiconductor laser bar that is behind the higher semiconductor laser bar due to a difference in height between adjacent semiconductor laser bars or a slight step generated when the semiconductor laser bars are arranged. Instead of directly stacking the semiconductor laser bars on each other, spacers having a height lower than that of the semiconductor laser bars are inserted between the semiconductor laser bars so that the end surfaces of all the semiconductor laser bars are projected from the spacers on both sides so that the end surface coating is performed. Further, this spacer also serves as a covering material for preventing undesired optical thin film from adhering to the electrode surface of the semiconductor laser bar, and the height must be a height that covers a predetermined area of the electrode. . Further, as the material, for example, silicon, metal, ceramic or the like is used.

An example of a conventional end face coating method will be described with reference to FIG. 3 showing a perspective view. The semiconductor laser bar 1 has a substantially rectangular parallelepiped semiconductor laser element having a light emitting surface 2a and a light emitting back surface 2b facing each other, and two electrode surfaces 3a, 3b facing each other, and these four surfaces 2a, 2b, 3 are provided.
The surfaces other than a and 3b are arranged in a line. For example, the semiconductor laser element is composed of about 40 to 60 semiconductor laser elements, and the height H2 in the figure is about 500 μm and the length L1 is about 10 mm, which is a very elongated shape.

In the method of forming optical thin films having different reflectances on the light emitting surface 2a and the light emitting back surface 2b of the semiconductor laser bar 1, first, the semiconductor laser bar 1 and the spacer 4 are formed.
And the light emitting surface 2a (or the light emitting back surface 2b) may be aligned in an upward direction so as to be alternately stacked, and the electrode surfaces 3a and 3b of the semiconductor laser bar 1 are covered with the side surface 4a of the spacer 4. Here, the height H1 of the spacer (for example, about 480
μm) is a height that covers a predetermined region of the electrode surfaces 3a and 3b, and is lower than the height H2 (for example, about 500 μm) of the semiconductor laser bars 1, and the semiconductor laser bars 1 emit light in an alternately arranged state. The surface 2a becomes more protruding than the spacer 4 and is completely exposed to form a uniform optical thin film. Further, the length L1 of the spacer 4 (for example, about 15
mm is the length L2 of the semiconductor laser bar 1 (for example, about 1).
0 mm), the electrode surfaces 3a and 3b can be sufficiently covered, and the optical thin film material can be prevented from adhering to the electrode surfaces 3a and 3b. Normally, this arrangement work is performed manually by an operator using tweezers (not shown) or the like, but the semiconductor laser bar 1 and the spacer 4 are small and long and slender, so they are difficult to handle and require proficiency. It was a work that required devising that stress was not applied to the semiconductor laser bar 1 as much as possible so as not to cause cracks.

Next, this arrayed semiconductor laser bar 1
The spacer 4 and the spacer 4 are placed on the fixing jig 5 so that the light emitting surface 2a faces upward, and are fixed by being pressed by the slide-type pressing portion 7 utilizing the compressive force of the coil spring 6, for example. Next, the fixture 5 for which this setting is completed is put into a sputtering device (not shown), and is sputtered to emit light.
A predetermined optical thin film is coated on a. After the coating is completed, the fixing jig 5 is taken out from the sputter device (not shown), the slide type holding part 7 is loosened, and the semiconductor laser bar 1 and the spacer 4 are alternately piled up with tweezers (not shown). ) Or the like, the light emitting back surface 3b (uncoated surface) is turned upside down on the fixing jig 5. At this time, since the surfaces of the semiconductor laser bar 1 and the spacer 4 on the fixing jig 5 side are not aligned, the lower surface (coating completion surface) of the semiconductor laser bar 1 and the lower surface of the spacer 4 firmly adhere to the fixing jig 5. Hold it down and adjust the heights. When the reversing work and the height aligning work are completed, the work is fixed again by pressing with the slide-type pressing portion 7. By doing so, the light emitting back surface 2b (uncoated surface) becomes more protruding than the spacer 4 and is completely exposed, and a uniform optical thin film can be formed. next,
The fixture 5 for which this setting has been completed is put into a sputtering device (not shown), and the light emitting back surface 2b (uncoated surface)
Then, a predetermined optical thin film is coated. After the coating is completed, the fixing jig 5 is taken out from the sputtering device (not shown), the slide type holding portion 7 is loosened, and the semiconductor laser bar 1 and the spacer 4 are alternately piled up. 5, the semiconductor laser bar 1 and the spacer 4 are separated, and the end face coating operation is completed.
In the above description, the light emitting surface 2a is first coated, and then the light emitting surface 2a is inverted and the light emitting rear surface 2b is coated. However, this order may be reversed.

Here, the side surface 4a of the spacer 4 prevents the optical thin film material from entering through the gap with the semiconductor laser bar 1 during sputtering, and is in contact with the electrode surface 3.
The mirror surface has a high flatness so as not to scratch the a and 3b. However, because of this, the semiconductor laser bar 1 and the spacer 4 are in close contact with each other at their mirror surfaces, and because they are pressed against each other by the pressure of the coil spring 6 on the fixing jig 5, a van der Waals force is exerted between them. In some cases, an adhesive force was generated, and it was not possible to easily separate the fixing jig 5 by simply removing it. In such a case, the worker uses tweezers (not shown) or an adhesive sheet (not shown) to attach and fix one of the closely attached ones to the adhesive sheet (not shown) and pick up the other. It was necessary to separate the two by the method of, and the delicate work using nerves was forced. Also,
If the work of handling with tweezers (not shown) or the like increases, mechanical stress is applied to the semiconductor laser bar 1 although it is slight, which may cause scratches or cracks in the semiconductor laser bar 1.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in the work of separating the semiconductor laser bar and the spacer after coating both end surfaces of the semiconductor laser bar with an optical thin film, workability is improved. It is an object of the present invention to provide an end face coating method that improves mechanical properties and reduces mechanical stress applied to a semiconductor laser bar, and that does not cause scratches or cracks.

[0008]

According to the method of coating an end surface of a semiconductor laser of the present invention, a spacer is inserted between semiconductor laser bars to form a predetermined optical thin film on a light emitting surface and a light emitting back surface, and then the semiconductor laser bar and the spacer are formed. In the method for coating the end face of a semiconductor laser, the end face coating method for a semiconductor laser is characterized in that a recess opened to the outside is provided in the spacer in a state where the spacer and the semiconductor laser bar are in close contact with each other.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an end face coating method of the present invention will be described with reference to FIG. 1 which is a perspective view. The difference from the prior art is the shape of the spacer inserted between the semiconductor laser bars, and the same parts as those in FIG. The spacer 101 used in the end face coating method of the present invention has a spacer 10 on the side surface 101 a of the spacer 101 which overlaps the semiconductor laser bar 1.
1 has a groove 102 whose both ends are open along the longitudinal direction. The length W of the groove 102 in the lateral direction is determined by the spacer 101.
Height H1 (for example, about 480 μm), and the depth is not particularly limited. Here, if the opening area of the groove 102 is set to 40% to 70% of the area where the spacer covers the semiconductor laser bar, the mechanical strength of the spacer is not significantly deteriorated. The spacer 101 is in close contact with the semiconductor laser bar 1 at portions other than the groove 102 on the side surface 101a, the contact area and contact strength between the semiconductor laser bar 1 and the spacer 101 are halved, and the two are easily separated.
For this reason, it is not necessary to forcibly separate the both by using tweezers (not shown) or an adhesive sheet (not shown), workability is improved, and there is a risk that the semiconductor laser bar 1 will be damaged or cracked. There is no. Further, since the groove 102 is open at both ends, when the chamber 102 (not shown) of the sputtering apparatus (not shown) is evacuated without enclosing air in the groove 102 in a state of being overlapped with the semiconductor laser bar 1,
There is no risk of adverse effects.

In the above, in order to reduce the contact area between the semiconductor laser bar 1 and the spacer 101, the spacer 10
Although the groove 102 with both ends open is provided on the side surface 101a of FIG. 1, one of the grooves 103 having one end closed, or the other end having both ends closed is used as a spacer having another structure in FIGS. 2A and 2B. Each of the embodiments provided with the groove 104 is shown as a perspective view. In this case, the mechanical strength of the spacer 101 is improved as compared with the structure in which the groove 102 with both ends open is provided. Groove 1
The lengths L3 and L4 of the openings 03 and 104 in the longitudinal direction are made longer than the length of the semiconductor laser bar 1 so that air is not contained therein. Further, FIG. 2C shows a perspective view of an embodiment in which a through hole 105 is provided as another configuration. In this case as well, the length L5 of the opening of the through hole 105 in the longitudinal direction is made longer than the length of the semiconductor laser bar 1 so as not to contain air.

[0011]

According to the end face coating method of the present invention, even if the adhesive force due to the van der Waals force is generated between the semiconductor laser bar and the spacer, since the recess is provided in the spacer, the adhesive area and the adhesive strength are reduced. Therefore, the semiconductor laser bar and the spacer can be easily separated, the workability is improved, and the forced separation work by tweezers or the like is unnecessary, so that the risk of scratches and cracks is reduced. Further, since the recess is partially opened in a state where the semiconductor laser bar and the spacer are overlapped with each other, air is not contained in the recess, and there is no possibility that the degree of vacuum during sputtering is adversely affected. Further, the area of the recess is 40% to 70% of the area where the spacer covers the semiconductor laser bar.
It is preferable to select (1) because it is possible to reduce the adhesion strength without significantly deteriorating the mechanical strength of the spacer.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an end face coating method of the present invention.

FIG. 2 is a perspective view showing an example of another spacer used in the end surface coating method of the present invention.

FIG. 3 is a perspective view of a conventional end face coating method.

[Explanation of symbols]

1 Semiconductor laser bar 2a Light emitting surface 2b light emission back 101 spacer 102 groove

Claims (5)

[Claims] 1. A spacer is inserted between semiconductor laser bars,
In a method of coating an end face of a semiconductor laser, in which a semiconductor laser bar and a spacer are separated after forming a predetermined optical thin film on a light emitting surface and a light emitting back surface, a recess opened to the outside in a state where the spacer and the semiconductor laser bar are closely attached to the spacer. A method for coating an end face of a semiconductor laser, which comprises: 2. The method for coating an end surface of a semiconductor laser according to claim 1, wherein an opening area of the recess is 40% to 70% of an area where the spacer covers the semiconductor laser bar. 3. The method for coating an end surface of a semiconductor laser according to claim 1, wherein the recess is a groove formed along the spacer longitudinal direction and having both ends open. 4. The method for coating an end surface of a semiconductor laser according to claim 1, wherein the recess is a groove formed along the longitudinal direction of the spacer and longer than the length of the semiconductor laser bar having both ends or one end closed. . 5. The recess according to claim 1, wherein the recess is a through hole formed along the longitudinal direction of the spacer, and the length of the opening of the through hole in the longitudinal direction is longer than the length of the semiconductor laser bar. End face coating method for semiconductor laser.