JP2005340333A - Semiconductor laser end face protective film forming jig and manufacturing method thereof, semiconductor laser, and manufacturing method of semiconductor laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming an end face protection film of a semiconductor laser which can prevent the attachment of particles to the end face during an end face protection film forming process and is simplified in working process. <P>SOLUTION: On a cradle 11, spacers 12 and semiconductor laser bars 13 are alternately arranged. The spacers 12 are formed of ceramic of high purity alumina, and their corners 15 are chamfered and rounded along the longitudinal direction thereof. On the surfaces of each laser bar 23 which cross at right angles with end faces of a resonator, electrodes 26 and 27 are formed, respectively. The spacers 12 and the laser bars 13 which are arranged in order are fixed in close contact with each other by a fixing jig 14, and thereafter, a protection film having one reflection factor is formed on the top face of each laser bar 13 which is a cleaved surface by sputtering or the like. Then, the spacers 12 and the laser bars 13 are integrally reversed together, and another protection film having another reflection factor is formed on another end face of the resonator of each laser bar. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a jig used in a step of forming an end face protective film of a semiconductor laser, a method of manufacturing a semiconductor laser using the jig, and the like.

  2. Description of the Related Art Conventionally, in a semiconductor laser, a structure in which a cleaved crystal face is used as a resonator end face, and an optical thin film is generally formed on the end face in order to protect the crystal face and control reflectivity at the end face. (See, for example, Patent Document 1 and Patent Document 2).

  A method for forming such an end face protective film will be described with reference to FIG. The semiconductor laser bars 3 are arranged on the flat support 1 with a space between the spacers 2 so as to expose the cleaved surface as the resonator end face (FIG. 5A). Next, an end face protective film forming jig (hereinafter referred to as a spacer) 2 is disposed between the laser bars 3 (FIG. 5B).

  At this time, the upper surface of the spacer 2 is set to be lower than the upper surface of the laser bar 3 in order to prevent the spacer from being shaded and forming a protective film at the end of the cleavage plane in the subsequent steps.

  After the aligned spacer 2 and laser bar 3 are fixed by the fixing jig 4, a protective film having a single reflectance is formed on the cleavage plane by sputtering or the like (FIG. 5C). Next, the spacer 2 is once removed from the flat support 1 and then the upper and lower surfaces of the laser bar 3 are reversed (FIG. 5D).

  Next, the spacers 2 are inserted and aligned between the laser bars 3, and a protective film having another reflectance is formed on the other resonator end face of the laser bar 3 (FIG. 5E).

The spacers used in the processes described above are mainly rectangular parallelepiped shapes as disclosed in Patent Document 1. In addition, since the upper surface of the spacer is lower than the end face of the laser bar at the center of the spacer as disclosed in Patent Document 2, the protective film is formed by going further from the cleaved surface of the laser bar to the side surface. As a result, there is an advantage that film peeling hardly occurs.
JP-A 64-9681 JP-A-9-83072

The spacer is required to have chemical resistance, heat resistance, and mechanical durability in order to remove the protective film such as SiO ₂ , SiN, and Al ₂ O ₃ and repeatedly use the spacer. Furthermore, it is necessary to prevent impurities such as heavy metals from being introduced into the laser bar during the protective film formation process. For these reasons, the spacer material is often made of silicon crystals.

  However, when a spacer made of silicon crystal is used, corner portions are missing due to repeated use. In particular, as described above, chipping is likely to occur in the process of removing the spacer and replacing the upper and lower surfaces of the laser bar, and there is a problem that fragments generated thereby adhere to the end surface of the laser bar and the protective film is not partially formed. Due to the absence of a protective film, film peeling is likely to occur, output abnormalities due to deterioration of the end face over time and reflectance fluctuations, and optical instantaneous destruction (COD) due to light absorption at the end face occur. May cause serious problems.

  In order to reduce such a problem, it is effective to use a ceramic spacer that does not easily cause chipping. However, in a normal rectangular parallelepiped shape, corners are not chipped.

  On the other hand, by using the spacer having the shape disclosed in Patent Document 2, there is a merit that prevention of film peeling and scratches at the end face can be prevented. Processing is difficult when using.

  Further, according to the shape disclosed in Patent Document 2, the spacers are high at both ends in the longitudinal direction so as to match the height of the laser bar. Wraparound is eliminated, and film peeling is likely to occur at this point.

  Therefore, the present invention has been made in view of the above problems, and it is possible to form a semiconductor laser end face protective film capable of adhering the protective film to the side surface of the laser bar by simple processing while preventing chipping at the corners. An object of the present invention is to provide a jig for use and a method for manufacturing a semiconductor laser using the jig.

  The semiconductor laser end face protective film forming jig of the present invention has a substantially rectangular parallelepiped shape and a substantially square cross section, and at least two adjacent corners of the substantially square are chamfered and formed of ceramic. Features.

  It is preferable that all four corners of the substantially rectangular shape are chamfered.

  More preferably, the chamfering process is performed over the longitudinal direction of the jig.

  Also, in the manufacturing method of the semiconductor laser end face protective film forming jig of the present invention, a rectangular parallelepiped bar made of ceramic is put together with an abrasive in the drum, and then the drum is rotated to rotate the bar. It is characterized by chamfering a corner.

  The semiconductor laser manufacturing method of the present invention includes a step of alternately arranging a semiconductor laser end face protective film forming jig and a semiconductor laser bar on a base, and end face protection so as to cover at least one resonator end face of the semiconductor laser bar. A method of manufacturing a semiconductor laser comprising a step of forming a film, wherein the jig is an end face protective film forming jig of the semiconductor laser of the present invention, and the jig is chamfered when viewed from above. A plurality of corners are arranged on the base so that both corners can be seen, and the top surface of the jig and the end face of the one resonator of the semiconductor laser bar are substantially at the same height when viewed from above the base. It is characterized by becoming.

  The semiconductor laser bar further includes a step of forming an end face protective film so as to cover the other end face of the resonator, and the jig has a base with an interval so that both the chamfered corners can be seen when viewed from above. It is preferable that a plurality of elements are disposed on the base plate so that the upper surface of the jig and the other resonator end surface of the semiconductor laser bar have substantially the same height when viewed from above the base.

  The radius of curvature of the chamfered corner is preferably equal to or smaller than the distance from one end of the electrode formed on the side surface of the laser bar to the one resonator end surface of the laser bar.

  More preferably, the radius of curvature of the chamfered corner is equal to or smaller than the distance from the other end of the electrode to the other resonator end face of the laser bar.

  The semiconductor laser of the present invention is a semiconductor laser manufactured by the above-described semiconductor laser manufacturing method, and a part of the end face protective film is substantially perpendicular to the one resonator end face or the other resonator end face. The end portion of the end face protective film on the substantially orthogonal plane has a cross-sectional shape reflecting the shape of the chamfered corner portion of the semiconductor laser end face protective film forming jig. It is characterized by that.

  According to the present invention, since the end face protective film forming jig is made of a ceramic material and the corner portion is chamfered, the corner portion is not chipped, and the defect of the protective film in the end face protective film forming step is not caused. Therefore, a stable semiconductor laser with a high yield can be manufactured.

  Furthermore, according to the present invention, the end face protective film forming jig can be manufactured by simple processing, and even if it is in close contact with the laser bar, a gap is generated in the chamfered portion, so that the protective film is formed on the side surface of the laser bar. It can be formed by wrapping around, and peeling of the protective film can be prevented over the entire length of the laser bar.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an explanatory diagram of a process for forming an end face protective film of a semiconductor laser according to an embodiment of the present invention.

  Spacers 12 and semiconductor laser bars 13 are alternately arranged on the cradle 11 (FIG. 1A). At this time, the laser bar 13 is arranged so that the end face of the resonator becomes the upper surface. Further, the height from the cradle 11 to the upper surface of the spacer 12 and the height to the upper surface of the laser bar 13 are made substantially the same. The spacer 12 is made of a ceramic of high purity alumina, and the corner portion 15 is chamfered and rounded in the longitudinal direction (FIG. 1B).

  Here, the laser bar is defined as a bar-shaped semiconductor laser in which a laser chip having a cavity end face exposed by cleaving a wafer on which a semiconductor laser element is formed is connected to one. In the present embodiment, as shown in FIG. 2, electrodes 26 and 27 are formed on the surfaces of the laser bar 23 that are orthogonal to the resonator end surfaces.

  Next, after the aligned spacers 12 and the laser bar 13 are fixed and fixed by the fixing jig 14, a protective film having a single reflectance is formed on the cleavage surface, which is the upper surface of the laser bar 13, by sputtering or the like (FIG. 1 (c)). Next, the spacer 12 and the laser bar 13 are inverted together, and a protective film having another reflectance is formed on the other resonator end face of the laser bar (FIG. 1D).

  FIG. 2 is a diagram showing the positional relationship between the corners of the spacer and the electrode end formed on the semiconductor laser in the embodiment of the present invention, and FIG. 3 is formed on the laser bar in the embodiment of the present invention. It is the figure which compared the cross-sectional shape of the end surface protective film with the cross-sectional shape of the end surface protective film formed on the laser bar at the time of using the conventional spacer.

  As shown in FIGS. 1B and 2, the spacer 22 formed of high-purity alumina ceramic is rounded by chamfering corners 25 along its longitudinal direction. The radius of curvature R at the corner 25 is designed to be the same or smaller than the distance L from the resonator end face of the laser bar 23 to the end of the electrode 26. For example, R and L are about 20 to 30 μm, and R ≦ L.

  As described above, according to the present embodiment, the spacer 12 is made of a ceramic material, and the corners of the spacer 12 are chamfered and rounded, so that the corners of the spacer are less likely to be chipped, and chipped fragments are generated. The partial loss of the protective film due to the adhesion of the fragments to the end face can be prevented. As a result, the manufacturing yield can be improved and the reliability deterioration due to local loss of the protective film can be greatly reduced, which is particularly effective in a high-power laser in which COD or the like easily occurs at the end face.

  Further, according to the present embodiment, the end face protective film can be formed so as to go around from the cavity end face, which is the upper surface of the laser bar, to the side surface even if the spacer and the laser bar are arranged in close contact with each other. It becomes possible. As a result, the protective film is difficult to peel off, the manufacturing yield can be improved, and reliability deterioration due to local film peeling can be greatly reduced. In addition, by setting the radius of curvature of the corner as described above at that time, it is possible to prevent the protective film from being formed on the side surface from being formed on the electrode, and the effect of preventing film peeling is greatly improved.

  As shown in FIG. 3, according to the present embodiment, the protective film that wraps around the side surface of the laser bar has a cross-sectional shape that reflects the shape of the spacer due to the presence of the chamfered spacer. Become. Specifically, when a conventional rectangular parallelepiped spacer is used, as shown in FIG. 3 (a), the end portion changes sharply, whereas the end portion of the end face protective film in the present embodiment As shown in FIG. 3B, the cross-sectional shape changes slightly compared to the conventional case. However, the shape varies depending on the degree of adhesion between the laser bar and the spacer and the shape of the corner of the spacer.

  In addition, according to the present embodiment, since the spacer and the laser bar are set to have the same height, after the protective film is formed on one of the resonator end faces, the laser bar 13 and the spacer 12 are fixed to the fixing jig 14. The upper and lower surfaces can be inverted while being fixed at, and the protective film can be formed on the other resonator end surface. Therefore, since the work of removing the spacer and replacing the upper and lower surfaces of the laser bar after the formation of the first protective film can be eliminated, it is possible to prevent the chipping of the spacer and the mechanical damage when handling the laser bar itself. For these reasons, the laser bar reversal operation can be eliminated, and the process can be simplified and the yield can be greatly improved.

  The corners of the spacer 12 only need to be chamfered at two adjacent portions, but if all four corners are chamfered, the spacer and the laser bar are set to have the same height. As a result, without removing the laser bar as described above, both end faces of the resonator can be formed so that the protective film wraps around the side face.

  Further, when forming the protective film for the second time, the radius of curvature R of the corner portion 15 of the spacer adjacent to the resonator end face of the laser bar 13 where the protective film is not yet formed is changed from the resonator end face of the laser bar 13 to the electrode 26. By setting the distance to be the same as or smaller than the distance to the other end, a protective film formed on both end faces of the resonator is formed on the electrode with a simple jig configuration and a simple method. In particular, it is possible to prevent film peeling in the step of dividing the laser bar into the respective laser elements by cleavage or the like.

  In the present embodiment, the spacer is made of a high-purity ceramic, but may be made of other materials such as SiC.

(Spacer manufacturing method)
FIG. 4 is an explanatory diagram of the spacer manufacturing process in the embodiment of the present invention.

  A high-purity alumina ceramic spacer 42 formed in a rectangular parallelepiped shape is put into the drum 43 together with an abrasive (not shown) (FIG. 4A). Next, the drum is rotated and held at a constant speed when the desired speed is reached (FIG. 4B). When the predetermined time has been reached, the drum is stopped, the spacer 42 'is taken out, and then the adhered abrasives and the dust from the polished spacer are removed by washing or blowing gas (FIG. 4C). .

  According to the above method, when the drum is rotated, the abrasive and the spacer 42 rub against each other, the corners are polished, and chamfering is performed. Since the radius of curvature of the corner is mainly determined by the polishing amount, that is, the rotation speed and rotation time of the drum, the adjustment can be performed easily and with high accuracy.

  INDUSTRIAL APPLICABILITY The semiconductor laser end face protective film forming jig and the semiconductor laser manufacturing method using the same of the present invention are useful for realizing a semiconductor laser having high yield and high reliability.

Process for forming an end face protective film of a semiconductor laser in an embodiment of the present invention The figure which showed the positional relationship of the corner | angular part of the spacer in embodiment of this invention, and the electrode edge part formed in the semiconductor laser The figure which compared the cross-sectional shape of the end surface protective film formed on the laser bar in embodiment of this invention with the cross-sectional shape of the end surface protective film formed on the laser bar at the time of using the conventional spacer. Manufacturing process explanatory drawing of the spacer in embodiment of this invention Process for forming a semiconductor laser end face protective film in the prior art

Explanation of symbols

1 Flat support base 2 End face protective film forming jig (spacer)
DESCRIPTION OF SYMBOLS 3 Laser bar 4 Fixing jig 11 Base 12 Spacer 13 Laser bar 14 Fixing jig 15 Spacer corner 22 Spacer 23 Laser bar 25 Spacer corner 26, 27 Electrode 42, 42 'Spacer 43 Drum

Claims (9)

A jig for forming a semiconductor laser end face protective film, having a substantially rectangular parallelepiped shape and a substantially quadrangular cross section, wherein at least two adjacent corners of the substantially square shape are chamfered and formed of ceramic. 2. The semiconductor laser end face protective film forming jig according to claim 1, wherein all four corners of the substantially rectangular shape are chamfered. 3. The semiconductor laser end face protective film forming jig according to claim 1, wherein the chamfering is performed over the entire longitudinal direction of the jig. A semiconductor laser end face protective film forming jig characterized in that a rectangular parallelepiped bar formed of ceramic is placed in a drum together with an abrasive and then the drum is rotated to chamfer the corners of the bar. Manufacturing method. A step of alternately arranging a semiconductor laser end face protective film forming jig and a semiconductor laser bar on a base;
A semiconductor laser manufacturing method comprising: forming an end face protective film so as to cover at least one resonator end face of the semiconductor laser bar,
The jig is a jig according to any one of claims 1 to 3,
A plurality of the jigs are arranged on the base at intervals so that both the chamfered corners can be seen when viewed from above,
A method of manufacturing a semiconductor laser, characterized in that an upper surface of the jig and the end face of the one resonator of the semiconductor laser bar have substantially the same height when viewed from the base. A step of forming an end face protective film so as to cover the other end face of the resonator of the semiconductor laser bar;
A plurality of the jigs are arranged on the base at intervals so that both the chamfered corners can be seen when viewed from above,
6. The method of manufacturing a semiconductor laser according to claim 5, wherein an upper surface of the jig and the other resonator end surface of the semiconductor laser bar are substantially at the same height when viewed from the base. The radius of curvature of the chamfered corner is equal to or smaller than a distance from one end of an electrode formed on a side surface of the laser bar to the one resonator end surface of the laser bar. 7. A method for producing a semiconductor laser according to 5 or 6. The radius of curvature of the chamfered corner is the same as or smaller than the distance from the other end of the electrode to the other resonator end face of the laser bar. The manufacturing method of the semiconductor laser of description. A semiconductor laser manufactured by the manufacturing method according to claim 5,
The end face protective film is formed so that a part thereof wraps around a plane substantially perpendicular to the one resonator end face or the other resonator end face,
An end portion of the end face protective film in the substantially orthogonal plane has a cross-sectional shape reflecting the shape of the chamfered corner portion of the semiconductor laser end face protective film forming jig.

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