JP3434447B2 - Method for manufacturing semiconductor laser device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is related to <br/> method of manufacturing a semiconductor laser device used as a light source such as an optical disk, have the name of the particular return light tracking error due to the reflection of
The method of manufacturing a semi-conductor laser element.

[0002]

2. Description of the Related Art Conventionally, there is a semiconductor laser device as shown in FIG. The semiconductor laser device 1 is in the form of a rectangular parallelepiped, and the dielectric film 2 is entirely formed on the front end face (hereinafter, simply referred to as front light emission face) of the two end faces on the side where the laser light is emitted. It is formed over. On the other hand, the dielectric film 3 is formed over the entire surface on the rear end face (hereinafter, simply referred to as the rear light emission face). In addition, 4 is an active layer, 5 is a light emitting portion of the active layer 4, 6 and 7 are electrodes, 8 is a semiconductor substrate, and 9 is a semiconductor substrate.
Is an epitaxial growth layer portion.

The dielectric films 2 and 3 have the following 2
There are two roles. First, the light emitting portion 5 for the laser light
It is possible to prevent the characteristics of the semiconductor laser device from being deteriorated due to damage of the semiconductor laser. Second, the film thickness is adjusted to set the reflectance of the laser light to a desired value, thereby controlling the characteristics such as the threshold of the semiconductor laser device. Incidentally, the above-mentioned both dielectric films 2, 3
Is formed by plasma CVD (chemical vapor deposition) or EB (electron beam) vapor deposition. Specifically, both dielectric films 2,
As shown in FIG. 5, the formation of 3 is performed on both light emitting surfaces 11 and 12 of the semiconductor laser bar 10 which is formed into one rod-shaped body and is subsequently divided into individual semiconductor laser elements.

By the way, when a semiconductor laser element is used as a light source of an optical pickup for generating three beams by a diffraction grating, as shown in FIG. 6, the laser emission light L1 is a diffraction grating (not shown). (3) is divided into three beams, one main beam and two sub-beams located on both sides of this main beam, and reflected by an optical disk (not shown). Then, a part of the reflected beams L2 and L3 of the two sub-beams pass through a half prism (not shown) and are located above the front light exit surface at a position of about 65 μm above and below about 65 μm of the light exit unit 5. And come back to.

However, in general, in a semiconductor laser device manufactured by vapor phase growth, the active layer 4 and the light emitting portion 5 at the front end portion of the active layer 4 are separated from the one electrode 6 by about 5 mm.
Located at μm. Therefore, the device thickness is about 100 μm
In this case, there is no problem because the reflected beam L2 on the electrode 6 side (epitaxial growth layer portion side) is not incident on the front light emitting surface again. However, the electrode 7 side
The reflected beam L3 (on the semiconductor substrate side) is incident on the front light exit surface again. As a result, the reflected beam L3
Will be reflected again by the front light exit surface and returned to the optical system of the optical pickup. Therefore, it causes a tracking error of the optical pickup.

In order to avoid the above, the reflected beam L3 on the side of the epitaxial growth layer on the front light exit surface is used.
It is necessary to reduce the reflectance of the portion that is exposed to 10% or less to reduce the amount of laser light returned to the optical system of the optical pickup. As described above, there are the following two methods for reducing the reflectance of the portion of the front light exit surface on the epitaxial growth layer side where the reflected beam L3 strikes.

In the first method, as shown in FIG. 7, a region 24 on the front light emitting surface 22 of the semiconductor laser device 21 which is hit by the reflected beam L3 and does not include the light emitting portion 23 is lowered to form a step. The part 25 is formed. In this case, since the surface of the formed step portion 25 is considerably rough, the reflected beam L3 is diffusely reflected and the amount of laser light returned to the optical system of the optical pickup is reduced.

Further, according to the second method, as shown in FIG. 8, the first portion is formed in a region 34 on the front light emitting surface 32 of the semiconductor laser element 31 which is hit by the reflected beam L3 and does not include the light emitting portion 33. The dielectric film 35 is formed, and then the second dielectric film 36 is formed on the entire front light emission surface 32. In this case, since the two-layer dielectric films 35 and 36 are formed in the region 34 where the reflected beam L3 hits, the above-mentioned regions are optimized by optimizing the film thickness of the two-layer dielectric films 35 and 36. The reflectance of 34 can be reduced to 10% or less.

As described above, there is a method shown in FIG. 9 as a method of forming a dielectric film only on a part of the surface. In this method, a plurality of semiconductor laser bars 37, which will be divided into individual semiconductor laser elements later, are aligned on the bar holder jig 39 so that the front light emitting surface 38 is exposed.
Then, in order to prevent the dielectric film from being formed in a portion other than the portion to be vapor-deposited, a protective plate 40 is attached to the front light emitting surface 38 side of the bar holder jig 39, and the protective plate 40 is attached.
Thus, the semiconductor laser bar 37 is vapor-deposited so as to cover the region where the dielectric film is not formed.

[0010]

However, the method of reducing the reflectance of the portion of the front light emitting surface on which the reflected beam from the optical disk hits has the following problems.

First, the first method (see FIG. 7) of forming the step portion 25 on the front light emitting surface 22 is not suitable for mass production because of the following reasons. That is, FIG. 10 shows the relationship between the depth h of the step in the formed step portion 25 and the obtained reflectance. From FIG. 10, when the depth h of the step is about 15 μm, the reflectance is not reduced to 10% or less, and the reflectance is 10%.
It can be seen that the depth h needs to be about 30 μm or more to be reduced below. The reason is as follows.

As shown in FIG. 11, the step portions 28 and 29 are formed in a curved surface. As a result, when the depth h1 of the step is large as shown in FIG. 11 (a), the direction of the curved surface forming the step portion 28 is inclined outward, so that the center of the curved surface is more than the direction of the reflected beam L3. Outside. Therefore, the reflected light of the reflected beam L3 is largely shifted to the outside as shown by the arrow (a), and the returned light is not incident on the optical system of the optical pickup (not shown). On the other hand, when the depth h2 of the step is small as shown in FIG. 11 (b), since the inclination of the curved surface forming the step portion 29 is small, the center of the curved surface is too much from the direction of the reflected beam L3. It does not shift. Therefore, the reflected light of the reflected beam L3 passes near the reflected beam L3 as shown by the arrow (b), and the returned light is incident on the optical system of the optical pickup.

However, in FIG. 7, there is a problem that the area of the electrode 26 becomes smaller when the depth h of the step is increased. Particularly in a low current laser, the distance between the front light emitting surface 22 and the rear light emitting surface 27 of the semiconductor laser device 21.
(Cavity length) needs to be about 180 μm or less. Therefore, when the step portion 25 having the depth h of about 30 μm is formed, the width of the electrode 26 becomes about 120 μm or less. Therefore, when the semiconductor laser device 21 is assembled into a laser package, high accuracy is required for die bonding to the electrode 26, which inevitably increases die bonding defects. In addition, due to the large depth h of the step, in the process of making the semiconductor laser bar into a device and inspecting the device characteristics, the chipping of the device frequently occurs and the appearance defect increases.

In the second method (see FIG. 8) of forming the two layers of dielectric films 35 and 36 on the front light emitting surface 32, the semiconductor laser bar 37 (see FIG. 9) is formed when the first dielectric film 35 is formed. The protective plate 40 that covers the front light emitting surface 38 in () needs to be in close contact with the front light emitting surface 38. Otherwise, the first dielectric film 35 is also formed on the area to be covered by the protective plate 40.
(See FIG. 8) is formed, and the reflectance at the light emitting portion 33 does not reach the desired reflectance. However,
In reality, since the width of the semiconductor laser bars 37 varies by about ± 10 μm, the front light emitting surfaces 38 of all the semiconductor laser bars 37 set on the bar holder jig 39.
Are not in the same plane. Therefore, there is a problem that it is impossible to bring the front light emitting surface 38 of all the semiconductor laser bars 37 into close contact with the protective plate 40. Further, while the thickness of the semiconductor laser bar 37 also varies by about ± 10 μm, the interval of the ladder-shaped gap of the protection plate 40 cannot be changed. Therefore, there is a problem that the number of semiconductor laser bars 37 that can be processed at one time is very small, which is not suitable for mass production.

[0015] Accordingly, an object of the present invention is to provide a method of manufacturing a semiconductor laser device which can produce a large amount of Na has semiconductors laser devices of the tracking error due to the reflection of the returning light.

[0016]

To achieve the above object, according to an aspect of method for producing a semi-conductor laser device of the invention according to claim 1, forming a groove of a plurality of the same direction on the semiconductor substrate side of the surface of the semiconductor laser wafer And a step of forming a first dielectric film on at least the wall surface of each groove, and cleaving the semiconductor laser wafer at each groove where the first dielectric film is formed to form a plurality of semiconductor laser bars. It is characterized by including a step of forming and a step of forming a second dielectric film on the divided surface of the semiconductor laser bar by the cleavage and the surface on which the wall surface of the groove was formed.

According to the above structure, the flat surface of the light emitting surface of the semiconductor laser element, which will be the surface including the light emitting portion, is obtained when the semiconductor laser wafer is cleaved at each groove where the first dielectric film is formed. First appears in. Therefore, the first dielectric film is not formed at all on the plane formed by the division surface that appears by this cleavage, and when the second dielectric film is formed later, the second dielectric film is formed on the plane. On the other hand, only the first dielectric film and the second dielectric film are formed on the surface that formed the wall surface of the groove (hereinafter referred to as the step portion). From the above, the first and second
By optimally adjusting the film thickness of the dielectric film, a semiconductor laser device in which the reflectance of the plane including the light emitting portion on the light emitting surface and the reflectance of the stepped portion are desired reflectance is It is possible to obtain a high yield without using a special jig.

Further, the width of the groove may be such that the first dielectric film can be formed on the wall surface of the groove. Therefore, for example, when the first dielectric film is formed by plasma CVD or EB vapor deposition, the width of the groove is 10 μm.
If it is about m or more, the above first
A dielectric film can be formed. As a result, the resonator length is 18
When forming a semiconductor laser device having a thickness of 0 μm, the width of the electrode formed on the semiconductor substrate is secured to be about 170 μm.

The invention according to claim 2 is the method for manufacturing a semiconductor laser device according to claim 1 , wherein the groove is formed by physically scraping off the surface of the semiconductor laser wafer on the semiconductor substrate side by dicing or the like. It is characterized by forming.

According to the above structure, since the groove formed on the surface of the semiconductor substrate is formed by a method of physically scraping the surface of the semiconductor substrate, the material of the semiconductor substrate is limited. Without forming the groove.

According to a third aspect of the present invention, in the method of manufacturing a semiconductor laser element according to the first aspect , the groove is chemically formed on the surface of the semiconductor laser wafer on the semiconductor substrate side by reactive ion etching or the like. It is characterized in that it is formed by a dissolving method.

According to the above structure, the groove formed on the surface on the semiconductor substrate side is formed by a method of chemically dissolving the surface on the semiconductor substrate side. The width and the depth of the groove can be accurately set by selecting the appropriate.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a sectional view of the semiconductor laser device according to the present embodiment.

The present semiconductor laser device 41 has a substantially rectangular parallelepiped shape, and has a larger distance from the light emitting portion 43 on the front light emitting surface 42 to the electrodes 44 and 45 (that is, the semiconductor substrate portion). On the side), a step portion 46 is provided. Similarly, a step portion 48 is also provided on the rear light emitting surface 47. Then, a silicon nitride film (film thickness λ / 4: λ is the wavelength of the laser beam) is first formed on the surface of the step portions 46 and 48.
The dielectric film 49 is formed. Further, the front light exit surface 4
The second dielectric film 50 is formed of alumina film (film thickness λ / 2) over the entire surface of No. 2. Thus, the front light exit surface 4
In the area where the return light (not shown) from the optical disk hits in 2 and does not include the light emitting portion 43, a desired reflectance of 3% is obtained by the two layers of dielectric films 49 and 50.
Further, in the region including the light emitting portion 43, the desired reflectance of 30% is obtained by the single layer of the second dielectric film 50. In addition, a multilayer dielectric film formed of an alumina film (thickness λ / 4), an amorphous silicon film (thickness λ / 4) and an alumina film (thickness λ / 2) is formed on the entire rear light emission surface 47. 51 is formed. The desired reflectivity of this multilayer dielectric film is 74%. Reference numeral 52 is an active layer.

The semiconductor laser device 41 having the above structure is formed by the following procedure. FIG. 2 shows a semiconductor laser device 41.
2 shows a cross section of a semiconductor wafer for forming a. 5 in the figure
Reference numeral 5 denotes a division surface when the semiconductor wafer is divided into semiconductor laser bars. The split surface 55 serves as a light emitting surface of each semiconductor laser device.

First, as shown in FIG. 2A, the upper electrode 45 is formed on the surface of the semiconductor wafer on the semiconductor substrate 56 side, while the lower electrode 44 is formed on the surface of the epitaxial growth layer 57 side. To be done.

Next, as shown in FIG. 2B, a region of the upper electrode 45 having a predetermined width centered on the dividing surface 55 is removed by using a photolithography technique and an etching technique. The structure of the upper electrode 45 in the present embodiment is AuGe / Ni / Mo / Au, and the etching solution used is H ₂ O _{2 for} Mo and an iodine-based etchant for AuGe, Ni, Au. Further, the width of the upper electrode 45 to be removed may be equal to or larger than the width of the groove formed in the next step, and is 30 μm in the present embodiment.

Next, as shown in FIG. 2C, the groove 5 is formed in the region of the semiconductor substrate portion 56 where the upper electrode 45 is removed.
8 is formed. This groove 58 finally forms the step portions 46, 4 of the front light emitting surface 42 and the rear light emitting surface 47 in FIG.
It becomes 8. The depth of the groove 58 depends on the step portion 4 formed later.
The depth may be such that the return light hits 6,48. The method of forming the groove 58 is not particularly limited, but the dicing method is used in the present embodiment. In that case, the width of the dicing plate is 25 μm and the width is 3
A groove 58 of 0 μm was obtained. However, the depth of the groove 58 is 50 μm.

Next, as shown in FIG. 3D, the groove 58 is formed.
The first dielectric film 49 is formed on the wall surface of. In that case, the first dielectric film 49 'is also formed on the upper electrode 45, but this first dielectric film 49' is removed in a later step.
In the present embodiment, a silicon nitride film (film thickness λ / 4) is formed on the first dielectric film 49 by using the plasma CVD method.

Next, as shown in FIG. 3E, the semiconductor wafer is cleaved at the dividing surface 55 (groove 58) to obtain a semiconductor laser bar 59. In this case, the light emitting surfaces 60, 6
The surface including the active layer end portions 62 and 63 of No. 1 is exposed for the first time. Therefore, unlike the conventional method of reducing the reflectance in which the two-layer dielectric film is formed on the light emitting surface, the light emitting portion 43 is never covered with the first dielectric film 49. .

Next, as shown in FIG. 3 (f), the second dielectric film is formed on the entire surface of the light emitting surface 60 which will be the front light emitting surface (that is, on the active layer end portion 62 and the step portion 64). Form 50. In this embodiment, an alumina film (film thickness λ / 2) is vapor-deposited by the EB vapor deposition method. At this point, the first dielectric film 49 and the second dielectric film 5 are formed on the step portion 64 of the light emitting surface 60.
0 is formed in two layers, and only the second dielectric film 50 is formed at the active layer end portion 62. On the other hand, an alumina film (film thickness λ / 4), an amorphous silicon film (film thickness λ / 4) and an alumina film (film thickness λ / 2) is vapor-deposited to form the multilayer dielectric film 51.

Next, both light emitting surfaces 60, 61 of the semiconductor laser bar 59 are protected by a resist, and the unnecessary first dielectric film 49 'formed on the upper surface of the upper electrode 45 is removed by an HF-based etching solution. To remove by etching. Thus
A semiconductor laser bar 59 as shown in FIG. 3 (g) is obtained. After that, the semiconductor laser bar 59 is cut at a predetermined interval in the longitudinal direction to be made into chips, and a semiconductor laser element as shown in FIG. 1 is obtained.

When the reflectance of the front light emitting surface 42 of the semiconductor laser device manufactured by the above method was measured, it was 30.6% at the light emitting portion 43 and 4.3% at the step portion 64. The reflectance of the rear light emitting surface 47 is 7
It was 2.9%. Therefore, the reflectance of the step portion 46 on the front light exit surface 42, which the sub-beam return light strikes,
The amount of light returned to the optical system of the optical pickup can be made lower than 10% which is necessary for sufficiently reducing the amount. On the other hand, the reflectance of the light emitting portion 43 can be set to 25% or more, which is necessary for causing the laser light to resonate and emit.

Therefore, when the semiconductor laser device according to the present embodiment is used as the light source of the optical pickup which generates three beams by the diffraction grating, it is divided into three beams and reflected by the optical disk. Regarding the return light of the sub-beam that has entered the step portion 46 of the front light emission surface 42 of the return light, the amount of light reflected by the step portion 46 and returned to the optical system of the optical pickup is sufficiently low. As a result, the tracking error of the optical pickup due to the reflection of the return light does not occur.

As described above, in the present embodiment,
A step portion 46 is provided in a region of the front light emitting surface 42 of the semiconductor laser device, which is a portion where the return light from the optical disk strikes and which does not include the light emitting portion 43. Then, the first dielectric film (silicon nitride film (film thickness λ / 4)) 49 is formed only on the wall surface of the step portion 46, and the second dielectric film 49 is formed on the entire front light emission surface 42.
A dielectric film (alumina film (film thickness λ / 2)) 50 is formed. In that case, the first dielectric film 49 is formed only on the surface of the step portion 46. Therefore, the first dielectric film 49
By adjusting the film thickness of the second dielectric film 50, the reflectance of the step portion 46 can be reduced to 10% or less, and the amount of the return light which hits the step portion 46 and is returned to the optical system of the optical pickup is sufficiently increased. Can be made very small. Therefore,
According to the present embodiment, it is possible to prevent the tracking error of the optical pickup due to the reflection of the return light that hits the step portion 46. On the other hand, the light emitting portion 4 other than the step portion 46
The reflectance of the region including 3 can be made higher than 25% to maintain the reflectance required for causing the laser light to resonate and emit.

Further, as described above, the reflectance of the step portion 46 has a sufficiently small value of 10% or less due to the formation of the first and second dielectric films 49 and 50. . Therefore, the direction of the surface of the stepped portion 46 is changed to the stepped portion 46.
It is not necessary to set the direction in which the return light impinging on is not returned to the optical system of the optical pickup positively. In short, it is not necessary to increase the horizontal depth of the step portion 46. More specifically, the depth may be such that the first dielectric film 49 can be formed on the wall surface of the step 46 by the plasma CVD method or the like. Therefore, the area of the upper electrode 45 determined by the depth of the step portion 46 of the front light emission surface 42 and the depth of the step portion 48 of the rear light emission surface 47 can be made sufficiently large. Specifically, when forming a low current laser having a cavity length of 180 μm, the depth of the step portion 46 is set to 5 μm.
The width of the upper electrode 45 can be increased to about 170 m. Therefore, die assembly to the upper electrode 45 can be facilitated when the laser package is assembled. Further, since the depth of the step portion 46 is small, cracking and chipping can be reduced.

In the semiconductor laser device, the upper electrode 45 is formed on the surface of the semiconductor wafer on the semiconductor substrate 56 side, while the lower electrode 44 is formed on the surface of the epitaxial growth layer 57 side. Then, a groove 58 is formed on the upper electrode 45 side, and a first dielectric film 49 is formed on the wall surface of this groove 58.
After that, the semiconductor laser bar 59 is obtained by cleavage at the groove 58, and the second dielectric film 50 is formed on the entire surface of the light emitting surface 60 serving as the front light emitting surface of the semiconductor laser bar 59.
The multilayer dielectric film 5 is formed on the entire surface of the light emitting surface 61 which becomes the rear light emitting surface.
1 is formed. Then, the first dielectric film 4 on the upper electrode 45
After removing 9 ′, the semiconductor laser bar 59 is cut at predetermined intervals in the longitudinal direction to be formed into chips.

Therefore, according to the method of manufacturing a semiconductor laser device of the present embodiment, the region including the light emitting portion 43 other than the step portion 46 in the front light emitting surface 42 has the first dielectric on the wall surface of the step portion 46. It appears after the body film 59 is formed, and the first dielectric film 59 is formed only on the step portion 46. That is, according to the present embodiment, the first dielectric film 49 and the second dielectric film 50 are formed in two layers on the wall surface of the step portion 46 in the front light emission surface 42, and the layers other than the step portion 46 are formed. Since only the second dielectric film 50 is formed on the front light emitting surface 42, a semiconductor laser device having a desired reflectance can be easily obtained with a high yield. Further, a special jig such as the bar holder jig 39 and the protective plate 40 shown in FIG. 9 is not required, and a large amount of semiconductor laser devices can be manufactured at one time with good workability.

That is, according to the present embodiment, it is possible to mass-produce semiconductor laser devices without a tracking error due to reflection of return light.

In the method of manufacturing the semiconductor laser device according to the present embodiment, the dicing method is used when forming the groove 58 on the surface of the semiconductor wafer on the side of the semiconductor substrate 56, but the argon ion beam etching method is used. You may use. In either case, since the groove 58 is formed by physically scraping off the semiconductor substrate, the material selectivity of the semiconductor substrate is small.

Further, as a method of forming the groove 58, a reactive ion etching method can be used. In that case, since etching proceeds by a chemical reaction, it is necessary to select an etching gas depending on the material of the semiconductor substrate. For example, if the semiconductor substrate is a GaAs substrate, a CCl ₂ F ₂ based etching gas is used. According to this method, the width and depth of the groove 58 can be accurately set by appropriately selecting the etching time and the like.

Further, in the present embodiment, the first
Although a silicon nitride film (film thickness λ / 4) is formed as the dielectric film 49 by the plasma CVD method, an alumina film (film thickness λ / 4) may be formed by the EB vapor deposition method. In this case, both the first and second dielectric films 49 and 50 are alumina films, but the obtained effect is the same as that of the above-mentioned embodiment.

In addition, in the present embodiment, the second
Although the alumina film (film thickness λ / 2) is formed as the dielectric film 50 by the EB vapor deposition method, the silicon nitride film (film thickness λ / 2) may be formed by the plasma CVD method. In this case, both the first and second dielectric films 49 and 50 are silicon nitride films, but the effects obtained are the same as those in the above embodiment.

[0044]

As apparent from the above, according to the present invention, a manufacturing method of a semi-conductor laser element according to the invention of claim 1 includes the steps of forming a groove in the plurality of the same direction on the semiconductor substrate side of the surface of the semiconductor laser wafer, A step of forming a first dielectric film on a wall surface of each groove, and a step of cleaving the semiconductor laser wafer at a position of each groove where the first dielectric film is formed to form a plurality of semiconductor laser bars, Since the step of forming the second dielectric film on the split surface of the semiconductor laser bar by the cleavage and the surface on which the wall surface of the groove has been formed is provided, a region including the light emitting portion of the light emitting surface will be formed later. The first region described above appears only when the semiconductor laser wafer is cleaved at the position of each groove in which the first dielectric film is formed. Therefore, the first dielectric film is not formed at all in the first region, which is formed by the split surface and appears by the cleavage. Therefore, by forming the second dielectric film later, only the second dielectric film is formed in the first region, while the first region is formed in the second region other than the first region on the light emitting surface. Therefore, the second two-layer dielectric film can be formed.

Therefore, according to the present invention, by adjusting the film thicknesses of the first and second dielectric films to the optimum values, the reflectance of the first and second regions on the light emitting surface can be adjusted to desired reflection. It is possible to obtain a semiconductor laser device having a high yield with a high yield. In addition, no special jig is required when forming the first dielectric film only in the second region. Therefore, a large amount of semiconductor laser devices can be manufactured once with good workability.

Further, the width of the groove is 1 when the first dielectric film is formed by plasma CVD or EB vapor deposition.
It may be about 0 μm or more. Therefore, even in the case of the current-stopping laser device having the cavity length of 180 μm, the width of the electrode formed on the semiconductor substrate can be secured to be about 170 μm. That is, according to the present invention, it is possible to manufacture a semiconductor laser device with less die-bonding defects when assembled in a laser package and with fewer cracks.

That is, according to the present invention, it is possible to mass-produce semiconductor laser devices free from the tracking error due to the reflection of the return light.

In the method of manufacturing a semiconductor laser device according to the second aspect of the present invention, the groove is formed by physically scraping the surface of the semiconductor laser wafer on the semiconductor substrate side by dicing or the like. The groove can be formed without limiting the material.

In the method for manufacturing a semiconductor laser device according to the third aspect of the present invention, the groove is formed by a method of chemically dissolving the surface of the semiconductor laser wafer on the semiconductor substrate side by reactive ion etching or the like. The width and depth of the groove can be accurately set by appropriately selecting the identity of the chemical substance used, the processing time, and the like.

[Brief description of drawings]

FIG. 1 shows a method of manufacturing a semiconductor laser device according to the present invention.
FIG. 3 is a cross-sectional view of a semiconductor laser device manufactured by

FIG. 2 is a diagram showing a procedure for forming the semiconductor laser device shown in FIG.

FIG. 3 is a diagram showing a forming procedure following FIG. 2;

FIG. 4 is a diagram showing a conventional semiconductor laser device.

5 is an explanatory view of a method of forming a dielectric film in the semiconductor laser device shown in FIG.

FIG. 6 is an explanatory diagram of a reflected beam when a semiconductor laser element is used as a light source of an optical pickup that generates three beams by a diffraction grating.

FIG. 7 is an explanatory diagram of a conventional method for reducing the reflectance of a portion where a reflected beam of a sub beam strikes.

FIG. 8 is an explanatory diagram of a reflectance lowering method different from that in FIG.

9 is an explanatory view of a jig for forming a dielectric film only on a part of the surface in the reflectance lowering method shown in FIG.

10 is a diagram showing the relationship between the depth of the step and the reflectance obtained by the reflectance reduction method shown in FIG.

11 is an explanatory diagram of a relationship between a depth of a step and a reflection direction of return light, which is obtained by the reflectance lowering method shown in FIG.

[Explanation of symbols]

41 ... Semiconductor laser element, 42, 60 ... Front light emitting surface, 43 ... Light emitting portion, 44 ... Lower electrode, 45 ... Upper electrode, 46, 48,
64, 65 ... stepped portion, 47, 61 ... rear light emission surface,
49 ... First dielectric film, 50 ... Second dielectric film,
51 ... Multilayer dielectric film, 55 ... Dividing surface,
58 ... Groove, 59 ... Semiconductor laser bar.

Claims (3)

(57) [Claims] 1. A step of forming a plurality of grooves in the same direction on a surface of a semiconductor laser wafer on the semiconductor substrate side, a step of forming a first dielectric film on at least a wall surface of each groove, and the first dielectric. A step of forming a plurality of semiconductor laser bars by cleaving the semiconductor laser wafer at the location of each groove where a film is formed, and a dividing surface by the cleavage in the semiconductor laser bar and a surface forming a wall surface of the groove. A method of manufacturing a semiconductor laser device, comprising the step of forming a second dielectric film. 2. The method for manufacturing a semiconductor laser device according to claim 1 , wherein the groove is formed by a method of physically scraping off a surface of the semiconductor laser wafer on the semiconductor substrate side by dicing or the like. Laser element manufacturing method. 3. The method for manufacturing a semiconductor laser device according to claim 1 , wherein the groove is formed by a method of chemically dissolving the surface of the semiconductor laser wafer on the semiconductor substrate side by reactive ion etching or the like. A method of manufacturing a characteristic semiconductor laser device.