Semiconductor laser element manufacturing method, semiconductor laser element, and semiconductor laser device

Abstract

Provided is a method for manufacturing a semiconductor laser element (1) comprising a plurality of waveguides (21), the method comprising: a first dividing step in which a substrate (10) having formed thereon a nitride-based semiconductor laser laminate structure (20) is divided along a first direction to fabricate a divided substrate (3); a cleaving step in which the divided substrate (3) is cleaved along a second direction orthogonal to the first direction to fabricate a semiconductor laser element (5); and a second dividing step in which the semiconductor laser element (5) is divided along the first direction to remove at least one end of the semiconductor laser element (5) in the longitudinal direction thereof. The cleaving step includes a first cleaving step for forming in the divided substrate (3) a cleavage introducing groove (4) extending in the second direction, and a second cleaving step for cleaving the divided substrate (3) along the longitudinal direction of the cleavage introducing groove (4). In the second dividing step, a portion of the semiconductor laser element (5) including the cleavage introducing groove (4) is removed.

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a semiconductor laser element, a semiconductor laser element, and a semiconductor laser device including the semiconductor laser element. [Background technology]

[0002] Semiconductor laser elements have advantages such as a long life, high efficiency, and small size, and are therefore used as light sources for a variety of applications, including image display devices such as projectors, and their range of applications is expanding to include light sources for vehicle headlamps and laser processing devices.

[0003] In recent years, semiconductor laser elements have been required to have even higher output power. For example, semiconductor laser elements used as light sources for laser processing equipment are required to have a high optical output power of over 1 watt.

[0004] In this case, if a high-power laser beam is emitted from one emitter (light-emitting portion), the light density at the front end face from which the laser beam is emitted may become too high, possibly causing catastrophic optical damage (COD) at the front end face.

[0005] Therefore, in order to emit a high-power laser beam from a single semiconductor laser element, a semiconductor laser element having a multi-emitter structure in which multiple emitters are integrated has been proposed (for example, Patent Document 1). This type of semiconductor laser element is configured, for example, as a laser bar having multiple waveguides. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-073669 Summary of the Invention [Problem to be solved by the invention]

[0007] A semiconductor laser element having a plurality of waveguides is formed by dividing a substrate (wafer) on which a semiconductor laminate structure made of semiconductor materials such as nitride-based semiconductor materials is formed. In this case, dividing grooves are formed by laser scribing in the substrate on which the semiconductor laminate structure is formed, and the substrate is divided into a plurality of pieces by breaking and cleaving the substrate along the dividing grooves.

[0008] At this time, the semiconductor material such as nitride crystal and the substrate melt due to the laser scribing, causing sputtering, and therefore processing waste called debris accumulates in the laser scribed area and its surrounding area.

[0009] However, if dividing grooves and debris remain in the mounting area of ​​the semiconductor laser element, when the semiconductor laser element is mounted on a submount or the like, problems may occur, such as the semiconductor laser element tilting and not being able to be mounted in a predetermined orientation, or the characteristics of the semiconductor laser element being deteriorated.

[0010] Typically, the basic structure of a semiconductor laser element, such as the waveguide and semiconductor stack structure, is formed on the front surface (e.g., p-side) of a substrate. On the other hand, only an electrode (e.g., n-electrode) is formed on the back surface of the substrate. The electrode pattern on the back surface is patterned by aligning a mask with the shape of the front surface (e.g., p-electrode pattern). As a result, there is a misalignment within the mask alignment accuracy between the basic structure of the semiconductor laser element on the front surface and the electrode pattern on the back surface. As will be described later, it is desirable to form the end faces of the laser cavity fabricated using cleavage to match the basic structure of the semiconductor laser element as accurately as possible. Therefore, it is better to perform the laser scribing required for cleavage according to the pattern on the front surface rather than the back surface, where there is a mask misalignment.

[0011] When mounting a semiconductor laser element on a submount or the like using junction-down mounting (face-down mounting) with the p-side surface of the semiconductor laser element as the mounting surface, if laser scribing is performed on the p-side surface of the semiconductor laser element and dividing grooves or debris are present in the mounting area of ​​the p-side surface of the semiconductor laser element, problems such as those described above will occur during mounting. However, in order to accurately fabricate a resonator that matches the basic structure of the semiconductor laser element, it is desirable to perform laser scribing on the p-side surface. In this way, the requirements of the mounting process and the requirements of chip processing conflict.

[0012] The present disclosure has been made to solve such problems, and aims to provide a method for manufacturing a semiconductor laser element, etc., that can obtain a semiconductor laser element that can suppress the occurrence of defects when mounted on a submount or the like. [Means for solving the problem]

[0013] In order to achieve the above object, one aspect of a manufacturing method of a semiconductor laser device according to the present disclosure is a manufacturing method of a semiconductor laser device having a plurality of waveguides, the method including a first dividing step of dividing a substrate having a nitride-based semiconductor laser stacked structure formed thereon, the nitride-based semiconductor laser stacked structure having a plurality of waveguides each extending in a first direction parallel to a first main surface, along the first direction to produce a plurality of divided substrates, each divided substrate having a plurality of the waveguides arranged at intervals in a second direction orthogonal to the first direction and parallel to the first main surface; a cleaving step of cleaving one of the plurality of divided substrates fabricated in the cleaving step along the second direction to fabricate a plurality of semiconductor laser elements each having a plurality of the waveguides; and a second dividing step of dividing one of the plurality of semiconductor laser elements fabricated in the cleaving step along the first direction to remove at least one end of the semiconductor laser element in the second direction, wherein the cleaving step includes a first cleavage step of forming cleavage guide grooves in the divided substrates, the cleavage guide grooves extending in the second direction, and a second dividing step of dividing the cleavage guide grooves into at least one end of the semiconductor laser element in the second direction. Usingand a second cleaving step of cleaving the divided substrate along the second direction, wherein in the second dividing step, a portion including the cleavage guide groove is removed as one end of the semiconductor laser element in the second direction.

[0014] Another aspect of a manufacturing method of a semiconductor laser device according to the present disclosure is a manufacturing method of a semiconductor laser device having a plurality of waveguides, the method including a first dividing step of dividing a substrate having a nitride-based semiconductor laser stacked structure formed thereon, the nitride-based semiconductor laser stacked structure having a plurality of waveguides each extending in a first direction parallel to a first main surface, along the first direction to manufacture a plurality of divided substrates, each of the divided substrates having a plurality of the waveguides arranged at intervals in a second direction perpendicular to the first direction and parallel to the first main surface; and a cleaving step of fabricating a plurality of semiconductor laser elements each having a plurality of the waveguides by cleaving the semiconductor laser element along a second direction parallel to the first main surface and perpendicular to the first direction, wherein the semiconductor laser element has a first side surface parallel to the first direction and a second side surface opposite to the first side surface, and wherein, in the semiconductor laser element, the shortest distance between two adjacent waveguides is defined as a first distance and the distance between the first side surface and one of the plurality of waveguides that is closest to the first side surface is defined as a second distance, and the second distance is wider than the first distance.

[0015] Furthermore, one aspect of a semiconductor laser element according to the present disclosure includes: a substrate having a first main surface and a second main surface opposite to the first main surface; and a nitride-based semiconductor laser stack structure formed above the first main surface of the substrate and having a plurality of waveguides extending in a first direction parallel to the first main surface, wherein the semiconductor laser element has a first side surface orthogonal to the first main surface and parallel to the first direction, a second side surface opposite to the first side surface, and a third side surface orthogonal to the first main surface and orthogonal to the first direction, the semiconductor laser element has a first region where the plurality of waveguides are formed, and a second region which is a region sandwiched between the first region and the first side surface, and when the semiconductor laser element is viewed from the first direction, a step portion recessed inward from a surface of the semiconductor laser element on the second main surface side is formed on the first side surface.

[0016] Another aspect of a semiconductor laser element according to the present disclosure includes: a substrate having a first main surface and a second main surface opposite to the first main surface; and a nitride-based semiconductor laser stack structure formed above the first main surface of the substrate and having a plurality of waveguides extending in a first direction parallel to the first main surface, wherein the semiconductor laser element has a first side surface orthogonal to the first main surface and parallel to the first direction, a second side surface opposite to the first side surface, and a third side surface orthogonal to the first main surface and orthogonal to the first direction, the semiconductor laser element having a first region where the plurality of waveguides are formed, and a second region sandwiched between the first region and the first side surface, wherein a first distance is a shortest distance between two adjacent waveguides and a second distance is a distance between the first side surface and one of the plurality of waveguides that is closest to the first side surface, the second distance being wider than the first distance.

[0017] Furthermore, one aspect of a semiconductor laser device according to the present disclosure includes any one of the semiconductor laser elements described above and a submount on which the semiconductor laser element is mounted, wherein the semiconductor laser element is mounted on the submount with the first main surface side facing the submount. [Effects of the Invention]

[0018] According to the present disclosure, it is possible to prevent problems from occurring when the device is mounted on a submount or the like. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram showing a configuration of a semiconductor laser device according to an embodiment. [Figure 2] FIG. 2 is a side view of the semiconductor laser device according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating a step of fabricating a semiconductor multilayer substrate in a method for manufacturing a semiconductor laser device according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating a step (first dividing step) of dividing the semiconductor multilayer substrate to prepare divided substrates in the method for manufacturing a semiconductor laser device according to the embodiment. [Figure 5] FIG. 5 is a view for explaining a step (first cleavage step) of forming cleavage guide grooves in the divided substrates in the method for manufacturing the semiconductor laser device according to the embodiment. [Figure 6] FIG. 6 is a diagram for explaining a step of dividing the divided substrates by cleavage (second cleavage step) in the method for manufacturing a semiconductor laser device according to the embodiment. [Figure 7A] FIG. 7A is a diagram showing a first example of the cleavage order when dividing the divided substrate. [Figure 7B] FIG. 7B is a diagram showing a second example of the cleavage order when dividing the divided substrate. [Figure 8] FIG. 8 is a diagram illustrating a step of forming division grooves in the semiconductor laser element in the method for manufacturing the semiconductor laser element according to the embodiment. [Figure 9] FIG. 9 shows a semiconductor laser element in which division grooves are formed and an SEM image of the semiconductor laser element in a cross section taken along line AA. [Figure 10]FIG. 10 is a view for explaining a step of removing an end portion of the semiconductor laser device (second dividing step) in the method for manufacturing the semiconductor laser device according to the embodiment. [Figure 11] FIG. 11 is a diagram showing a semiconductor laser element with the end portion removed and a micrograph of the first side surface of the semiconductor laser element as viewed from direction B. In FIG. [Figure 12A] FIG. 12A is a diagram showing a state in which the semiconductor laser device of the comparative example is mounted on a heat sink with the junction down. [Figure 12B] FIG. 12B is a diagram showing a state in which the semiconductor laser device according to the embodiment is mounted on a heat sink with the junction down. [Figure 13] FIG. 13 is a diagram showing the configuration of a semiconductor laser device according to a modified example. [Figure 14] FIG. 14 is a diagram showing a configuration of a first semiconductor laser device according to the embodiment. [Figure 15] FIG. 15 is a diagram showing a configuration of a second semiconductor laser device according to the embodiment. [Figure 16] FIG. 16 is a diagram showing a configuration of a third semiconductor laser device according to the embodiment. [Figure 17] FIG. 17 is a diagram showing a configuration of a fourth semiconductor laser device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below represents a preferred specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, arrangement and connection of the components, steps (processes), and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0021] Furthermore, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, the scales and the like do not necessarily match in each figure. In each figure, the same reference numerals are used to denote substantially the same components, and redundant explanations will be omitted or simplified.

[0022] In this specification and the drawings, the X-axis, Y-axis, and Z-axis represent the three axes of a three-dimensional Cartesian coordinate system. In this embodiment, the Z-axis direction is the vertical direction, and the direction perpendicular to the Z-axis (the direction parallel to the XY plane) is the horizontal direction. The X-axis and Y-axis are orthogonal to each other and are both orthogonal to the Z-axis. In this embodiment, the Y-axis direction is the "first direction," and the X-axis direction is the "second direction." The Y-axis direction, which is the first direction, and the X-axis direction, which is the second direction, are in-plane directions of the substrate 10. In other words, the Y-axis direction, which is the first direction, and the X-axis direction, which is the second direction, are parallel to the first main surface 11 and the second main surface 12 of the substrate 10. The Y-axis direction is the direction in which the waveguide 21 in the semiconductor laser device 1 extends (the laser cavity length direction). The directions in which the arrows on the X-axis, Y-axis, and Z-axis point are positive directions.

[0023] (Embodiment) [Configuration of semiconductor laser element] First, the configuration of a semiconductor laser device 1 manufactured by a manufacturing method for a semiconductor laser device 1 according to the present embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a diagram showing the configuration of a semiconductor laser device 1 according to the embodiment. In Fig. 1, (a) shows a top view of the semiconductor laser device 1, (b) shows a back view of the semiconductor laser device 1, and (c) shows a front view of the semiconductor laser device 1. Also, Fig. 2 is a side view of the semiconductor laser device.

[0024] In Fig. 1, the p-side electrode 30 and the n-side electrode 40 are hatched for the sake of convenience in order to make it easier to see the regions in which they are formed. In Fig. 1, the center line of the waveguide 21 is shown by a dashed line to indicate the position of the waveguide 21. This also applies to the subsequent drawings. In Fig. 2, the step portion 50 is hatched with dots for the sake of convenience in order to make it easier to see the region in which it is formed.

[0025] The semiconductor laser device 1 according to this embodiment is a semiconductor laser having a multi-emitter structure in which multiple emitters are integrated into one device, and emits multiple laser beams. Specifically, the semiconductor laser device 1 is a nitride-based semiconductor laser made of nitride-based semiconductor materials, and emits, for example, blue laser beam.

[0026] As shown in FIGS. 1 and 2, the semiconductor laser device 1 is a laser bar elongated in the X-axis direction, and includes a substrate 10, a nitride-based semiconductor laser stack structure 20, a p-side electrode 30, and an n-side electrode 40.

[0027] Substrate 10 has a first main surface 11 and a second main surface 12. Second main surface 12 is the surface opposite to first main surface 11 and faces back to first main surface 11. In this embodiment, first main surface 11 is the p-side surface that serves as the front surface, and second main surface 12 is the n-side surface that serves as the back surface.

[0028] For example, a semiconductor substrate such as a nitride semiconductor substrate is used as the substrate 10. In this embodiment, a hexagonal n-type GaN substrate is used as the substrate 10.

[0029] The nitride semiconductor laser stack structure 20 is a nitride semiconductor layer stack in which a plurality of nitride semiconductor layers, each made of a nitride semiconductor material, are stacked. The nitride semiconductor laser stack structure 20 is formed above the first main surface 11 of the substrate 10. For example, the nitride semiconductor laser stack structure 20 has a configuration in which an n-type cladding layer made of n-type AlGaN, an active layer made of undoped InGaN, a p-type cladding layer made of p-type AlGaN, and a p-type contact layer made of p-type GaN are sequentially stacked on the first main surface 11 of the substrate 10.

[0030] In addition to these nitride semiconductor layers, other nitride semiconductor layers such as an optical guide layer and an overflow suppression layer may be provided in the nitride semiconductor laser stack structure 20. Also, an insulating film having an opening at a position corresponding to the waveguide 21 may be formed on the surface of the nitride semiconductor laser stack structure 20.

[0031] The nitride-based semiconductor laser stack structure 20 has a plurality of waveguides 21 each extending in the Y-axis direction (a first direction parallel to the first principal surface 11) within the plane of the substrate 10. The plurality of waveguides 21 are arranged at intervals in the X-axis direction (a direction orthogonal to the first direction and parallel to the first principal surface 11). Specifically, the plurality of waveguides 21 are parallel to one another and formed at a predetermined pitch along the X-axis direction.

[0032] Each of the plurality of waveguides 21 functions as a current injection region and an optical waveguide in the semiconductor laser device 1. Each of the plurality of waveguides 21 corresponds to a respective one of a plurality of emitters that emit laser light. The plurality of waveguides 21 are formed, for example, in a p-type cladding layer in the nitride-based semiconductor laser laminate structure 20. As an example, the plurality of waveguides 21 have a ridge stripe structure, and are formed as a plurality of ridge portions in the p-type cladding layer. In this case, the p-type contact layer may be a plurality of semiconductor layers individually formed on each of the plurality of ridge portions, or may be a single semiconductor layer continuously formed to cover the plurality of ridge portions.

[0033] The p-side electrode 30 is formed on the nitride-based semiconductor laser laminate structure 20. The p-side electrode 30 is made of, for example, Pd, Pt, and Au. The p-side electrode 30 is formed on, for example, the p-type contact layer of the nitride-based semiconductor laser laminate structure 20. As shown in FIG. 1(a), in this embodiment, a plurality of p-side electrodes 30 are formed so as to correspond to the plurality of waveguides 21 (ridge portions). In other words, the p-side electrode 30 is formed in a divided form. Note that the p-side electrode 30 does not have to be divided into a plurality of parts. For example, the p-side electrode 30 may be a single electrode common to the plurality of waveguides 21.

[0034] The n-side electrode 40 is formed on the second main surface 12 of the substrate 10. The n-side electrode 40 is made of, for example, Ti, Pt, and Au. As shown in FIG. 1(b), in this embodiment, a plurality of n-side electrodes 40 are formed so as to correspond to the plurality of waveguides 21 (ridge portions). In other words, the n-side electrode 40 is formed in a divided form. Note that the n-side electrode 40 does not have to be divided into a plurality of parts. For example, the n-side electrode 40 may be a single electrode common to the plurality of waveguides 21.

[0035] As shown in FIGS. 1(a) to 1(c), the semiconductor laser device 1 has a first side surface 1a, a second side surface 1b, a third side surface 1c, and a fourth side surface 1d.

[0036] The first side surface 1a is one end surface in the longitudinal direction of the semiconductor laser device 1, and the second side surface 1b is the other end surface in the longitudinal direction of the semiconductor laser device 1. In other words, the second side surface 1b is the surface opposite to the first side surface 1a and faces away from the first side surface 1a. The longitudinal direction of the semiconductor laser device 1 is the X-axis direction, which is a direction perpendicular to the longitudinal direction of the waveguide 21.

[0037] In this embodiment, the first side surface 1a and the second side surface 1b are surfaces that are perpendicular to the first main surface 11 of the substrate 10 and parallel to the Y-axis direction (first direction). Specifically, the first side surface 1a and the second side surface 1b are surfaces that are parallel to the YZ plane.

[0038] The third side surface 1c is one end surface in the short side direction of the semiconductor laser device 1, and the fourth side surface 1d is the other end surface in the short side direction of the semiconductor laser device 1. In other words, the fourth side surface 1d is the surface opposite to the third side surface 1c and faces away from the third side surface 1c. The short side direction of the semiconductor laser device 1 is the Y-axis direction, which is a direction parallel to the waveguide 21.

[0039] In this embodiment, the third side surface 1c and the fourth side surface 1d are surfaces that are perpendicular to the first main surface 11 of the substrate 10 and perpendicular to the Y-axis direction (first direction). That is, the third side surface 1c and the fourth side surface 1d are surfaces that are parallel to the X-axis direction (second direction). Specifically, the third side surface 1c and the fourth side surface 1d are surfaces that are parallel to the XZ plane and perpendicular to the first side surface 1a and the second side surface 1b.

[0040] In this embodiment, the third side surface 1c and the fourth side surface 1d are cavity end surfaces of the semiconductor laser device 1. Specifically, the third side surface 1c is the front end surface of the semiconductor laser device 1. That is, laser light is emitted from the third side surface 1c. The fourth side surface 1d is the rear end surface of the semiconductor laser device 1. Although not shown, the third side surface 1c and the fourth side surface 1d are coated with an end surface coating film as a reflective film.

[0041] As will be described in detail later, the first side surface 1a, the second side surface 1b, the third side surface 1c, and the fourth side surface 1d are dividing surfaces when the semiconductor laser device 1 is fabricated from the wafer. Specifically, the first side surface 1a and the second side surface 1b are dividing surfaces when dividing along the Y-axis direction, and the third side surface 1c and the fourth side surface 1d are dividing surfaces when dividing along the X-axis direction. The third side surface 1c and the fourth side surface 1d are cleavage surfaces formed by cleavage. Therefore, the flatness of the third side surface 1c is higher than that of each of the first side surface 1a and the second side surface 1b. Similarly, the flatness of the fourth side surface 1d is higher than that of each of the first side surface 1a and the second side surface 1b. This allows light to resonate efficiently in the waveguide 21 between the third side surface 1c and the fourth side surface 1d, thereby obtaining laser light.

[0042] Furthermore, when the semiconductor laser element 1 is viewed from the X-axis direction, a step portion 50 is formed on the first side surface 1a, recessed inward from the surface on the second main surface 12 side of the semiconductor laser element 1. Similarly, a step portion 50 is formed on the second side surface 1b, recessed inward from the surface on the second main surface 12 side of the semiconductor laser element 1. In other words, the step portion 50 is formed so as to be recessed in the positive direction of the Z-axis from the surface on the second main surface 12 side, which is the back surface of the semiconductor laser element 1.

[0043] 2, in this embodiment, the step portion 50 is formed so as to extend from the surface on the second principal surface 12 side to within the thickness of the substrate 10. It does not reach the nitride-based semiconductor laser stack structure 20. The depth of the step portion 50 is set to a value that takes into consideration not to electrically short-circuit the pn junction formed in the nitride-based semiconductor laser stack structure 20. As indicated by the dotted hatching in FIG. 2, the step portion 50 is formed so that its shape in side view when viewed from the X-axis direction is approximately trapezoidal, but the shape of the step portion 50 is not limited to this.

[0044] 1(b), when the semiconductor laser device 1 is viewed from the Z-axis direction, the step portion 50 extends along the Y-axis direction. However, the step portion 50 does not reach the third side surface 1c and the fourth side surface 1d. In other words, one end of the step portion 50 in the Y-axis direction is located at a position set back from the third side surface 1c, and the other end of the step portion 50 in the Y-axis direction is located at a position set back from the fourth side surface 1d. Note that, as will be described in detail later, the step portion 50 is part of a dividing groove 6 used when dividing the semiconductor laser device.

[0045] As shown in FIG. 1, the semiconductor laser element 1 has a first region 110 in which a plurality of waveguides 21 are formed, a second region 120 sandwiched between the first region 110 and the first side surface 1a, and a third region 130 sandwiched between the first region 110 and the second side surface 1b.

[0046] In this embodiment, the p-side electrode 30 and the n-side electrode 40 are formed in the second region 120 and the third region 130, but the waveguide 21 is not formed in the second region 120 and the third region 130. Therefore, the second region 120 and the third region 130 do not function as semiconductor lasers, and laser light is not emitted from the second region 120 and the third region 130.

[0047] Furthermore, if the shortest distance between two adjacent waveguides 21 among the multiple waveguides 21 in the semiconductor laser element 1 is defined as a first distance d1, the distance between the first side surface 1a and the waveguide 21 closest to the first side surface 1a among the multiple waveguides 21 in the semiconductor laser element 1 is defined as a second distance d2, and the distance between the second side surface 1b and the waveguide closest to the second side surface 1b among the multiple waveguides 21 in the semiconductor laser element 1 is defined as a third distance d3, the second distance d2 and the third distance d3 are wider than the first distance d1.

[0048] In this embodiment, the first interval d1 exists in the first region 110. Specifically, all of the waveguides 21 in the first region 110 are formed at the same pitch. That is, all of the waveguides 21 in the first region 110 are formed at equal intervals, and the intervals between any two adjacent waveguides 21 in the first region 110 are all the same, the first interval d1.

[0049] Furthermore, the second interval d2 is the width in the X-axis direction of the second region 120, and the third interval d3 is the width in the X-axis direction of the third region 130. In the present embodiment, the second interval d2 and the third interval d3 are the same, but this is not limited to this.

[0050] As an example, the width (length in the X-axis direction) of the semiconductor laser element 1 is 9200 μm, and the length of the semiconductor laser element 1 in the cavity length direction (length in the Y-axis direction) is 1200 μm. In this case, the first interval d1 is d1=400 μm, and the second interval d2 and the third interval d3 are d2=d3=600 μm. That is, at both ends of the semiconductor laser element 1 in the longitudinal direction, there are a second region 120 and a third region 130 each having a width of 600 μm as regions where no waveguide 21 exists. Note that 21 waveguides 21 are formed in the first region 110, each 30 μm wide, at intervals of 400 μm, centered on the dashed dotted line.

[0051] [Method of manufacturing semiconductor laser element] Next, a method for manufacturing the semiconductor laser device 1 according to the embodiment will be described with reference to Fig. 1 and Fig. 3 to Fig. 11. Fig. 3 to Fig. 11 are views for explaining the method for manufacturing the semiconductor laser device 1 according to the embodiment. In Fig. 4, Fig. 5, Fig. 8, and Fig. 10, the debris is hatched with dots for the sake of convenience in order to make it easier to see the region where the debris is formed.

[0052] The method for manufacturing the semiconductor laser device 1 according to this embodiment is a method for manufacturing the semiconductor laser device 1 having a plurality of waveguides 21.

[0053] First, a semiconductor laminated substrate 2 in which semiconductor layers are laminated is fabricated as shown in Fig. 3. The semiconductor laminated substrate 2 is formed by forming a nitride-based semiconductor laser laminated structure 20 having a plurality of waveguides 21, a p-side electrode 30, and an n-side electrode 40 on a substrate 10 as a wafer.

[0054] For example, a hexagonal n-type GaN substrate is used as the substrate 10. Therefore, in this embodiment, as shown in Fig. 3, the [11-20] direction of the GaN substrate is the X-axis direction, the [1-100] direction of the GaN substrate is the Y-axis direction, and the

[0001] direction of the GaN substrate is the Z-axis direction.

[0055] To fabricate the semiconductor laminated substrate 2, first, a 2-inch n-type GaN substrate wafer is prepared as the substrate 10. Next, multiple nitride semiconductor layers are sequentially epitaxially grown on the entire first main surface 11 of the substrate 10. For example, an n-type cladding layer made of n-type AlGaN, an active layer made of undoped InGaN, a p-type cladding layer made of p-type AlGaN, and a p-type contact layer made of p-type GaN are sequentially formed on the first main surface 11 of the substrate 10 by metal organic chemical vapor deposition (MOCVD). Then, the stacked multiple nitride semiconductor layers are subjected to photolithography and etching to form a ridge stripe that becomes multiple waveguides 21. Each of the multiple waveguides 21 is formed along the [1-100] direction. This allows the nitride-based semiconductor laser laminated structure 20 having multiple waveguides 21 to be formed on the substrate 10. Thereafter, an insulating film is formed so as to partially cover the nitride-based semiconductor laser laminate structure 20, and further, a p-side electrode 30 is formed on the ridge stripe of the nitride-based semiconductor laser laminate structure 20. Next, the back surface of the substrate 10 is ground and polished to thin the substrate 10. As an example, the back surface of the semiconductor laminate substrate 2 having a thickness of 400 μm is polished until it becomes 85 μm thick. Then, an n-side electrode 40 is formed on the second main surface 12, which is the back surface of the thinned substrate 10. In this way, the semiconductor laminate substrate 2 can be fabricated.

[0056] Next, as a wafer shaping step, the semiconductor laminated substrate 2 shown in Fig. 3 is divided into a plurality of pieces (first dividing step). Specifically, the semiconductor laminated substrate 2 is divided along dividing lines shown by dashed lines in Fig. 3, thereby cutting out regions in which semiconductor laser elements 1 (laser bars) are to be fabricated into rectangular shapes.

[0057] In this embodiment, the semiconductor laminate substrate 2 is cut along the eight dividing lines shown in Fig. 3 to produce four divided substrates 3 as shown in Fig. 4. In this case, in this embodiment, laser scribing is performed on the surface of the semiconductor laminate substrate 2 on the side of the first main surface 11 of the substrate 10 (i.e., the front surface), and the semiconductor laminate substrate 2 is cut along the Y-axis direction, thereby dividing the semiconductor laminate substrate 2 into four pieces.

[0058] 3 and 4, the area surrounded by dashed lines is the effective area for extracting the semiconductor laser element 1, and is the area where the semiconductor laser element 1 is fabricated. As an example, the width W of the area where the semiconductor laser element 1 is fabricated (laser bar area) is 10,000 μm. Therefore, the width W in the X-axis direction of each of the four divided substrates 3 is 10,000 μm. Furthermore, in FIG. 3, the hatched area is a PCM (process control monitor) area 2a, which is an area not used for the semiconductor laser element 1. The width of each PCM area 2a is, for example, 1,200 μm.

[0059] Furthermore, when the thickness of the semiconductor laminate substrate 2 is 85 μm, the depth of the scribed grooves formed by laser scribing is approximately 50 μm from the surface on the first main surface 11 side of the semiconductor laminate substrate 2, and the width of the scribed grooves in a top view is approximately 5 μm. In this case, as shown in the enlarged view of FIG. 4 , by forming scribed grooves in the semiconductor laminate substrate 2 to cut the semiconductor laminate substrate 2, debris 3D with a width of approximately 30 μm accumulates on both sides of the scribed grooves on the front surface of the semiconductor laminate substrate 2. The debris 3D is processing waste of the semiconductor laminate substrate 2 generated when forming the scribed grooves in the semiconductor laminate substrate 2 by laser scribing, and in this embodiment, it accumulates on the surface of the semiconductor laminate substrate 2 on the p-side electrode side, which is the front surface. The scribed grooves in the first dividing step function as dividing grooves for dividing the semiconductor laminate substrate 2 into a plurality of divided substrates 3.

[0060] In this way, in the first dividing step, the substrate 10 on which the nitride-based semiconductor laser stack structure 20 is formed, having a plurality of waveguides 21 each extending in the Y-axis direction at intervals in the X-axis direction, is divided along the Y-axis direction to produce a plurality of divided substrates 3 each having a plurality of waveguides 21 arranged at intervals in the X-axis direction.

[0061] Note that, although the laser scribing in the first dividing step was performed on the surface (front surface) of the semiconductor laminated substrate 2 on the first main surface 11 side of the substrate 10, the present invention is not limited to this. That is, the laser scribing in the first dividing step may be performed on the surface (back surface) of the semiconductor laminated substrate 2 on the second main surface 12 side of the substrate 10. However, in this case, the debris 3D accumulates on the surface of the semiconductor laminated substrate 2 on the second main surface 12 side of the substrate 10 (i.e., the surface on the n-side electrode 40 side), and there is a risk that the debris 3D may get in the way in the next step (cleaving step). Therefore, it is better to perform the laser scribing in the first dividing step on the surface (front surface) of the semiconductor laminated substrate 2 on the first main surface 11 side of the substrate 10.

[0062] Next, one of the plurality of divided substrates 3 produced in the first dividing step is cleaved along the X-axis direction to produce a plurality of semiconductor laser elements 5, each having a plurality of waveguides 21 (cleaving step).

[0063] In this embodiment, the cleavage process includes a first cleavage process of forming cleavage guide grooves 4 extending in the X-axis direction in divided substrate 3, and a second cleavage process of cleaving divided substrate 3 along the longitudinal direction of cleavage guide grooves 4. The longitudinal direction of cleavage guide grooves 4 is the X-axis direction, which is perpendicular to waveguide 21.

[0064] The first cleavage step is a pre-step for cleaving the divided substrates 3, and involves forming cleavage guide grooves 4 as grooves that serve as starting points for cleavage. In other words, the cleavage guide grooves 4 are guide grooves for cleaving and dividing the divided substrates 3, and function as dividing grooves for dividing the divided substrates 3 into multiple pieces.

[0065] Specifically, in the first cleavage step, as shown in FIG. 5 , cleavage guide grooves 4 are formed near a first end face 3a, which is one end face of the divided substrate 3. More specifically, the cleavage guide grooves 4 are formed by cutting out the end of the divided substrate 3 from the first end face 3a toward the second end face 3b, which is the other end face of the divided substrate 3. In this embodiment, multiple cleavage guide grooves 4 are formed in the divided substrate 3 along the [11-20] direction by laser scribing. Therefore, the cleavage guide grooves 4 are laser scribed grooves formed by laser scribing. The multiple cleavage guide grooves 4 are formed at equal intervals along the Y-axis direction. As an example, the distance L between two adjacent cleavage guide grooves 4 is 1200 μm. This distance L between the cleavage guide grooves 4 ultimately matches the laser cavity length of the semiconductor laser device 1. The depth of cleavage guide grooves 4 formed by laser scribing is approximately 40 μm from the surface on the first main surface 11 side of divided substrate 3, and when viewed from above, cleavage guide grooves 4 are approximately 5 μm wide and approximately 350 μm long.

[0066] In this embodiment, laser scribing is performed on the surface of divided substrate 3 on the first main surface 11 side of substrate 10 (i.e., the front surface on the p-side electrode 30 side). This is because cleavage guide grooves 4 need to be accurately aligned with the shape of nitride-based semiconductor laser stack structure 20 (i.e., the mask pattern).

[0067] 5, by forming the cleavage guide grooves 4 in the divided substrate 3, debris 4D with a width of about 30 μm accumulates on both sides of the cleavage guide grooves 4 on the front surface of the divided substrate 3. The debris 4D is processing waste from the divided substrate 3 that is generated when the cleavage guide grooves 4 are formed in the divided substrate 3 by laser scribing.

[0068] The cleavage guide groove 4 formed in the first cleavage step is formed at a position corresponding to the second region 120 of the semiconductor laser device 1 shown in FIG. 1, and does not reach the waveguide 21 in the first region 110.

[0069] After the first cleavage step, a second cleavage step is performed. The second cleavage step is a step for cleaving the divided substrate 3, and the divided substrate 3 is divided by cleaving starting from the cleavage guide grooves 4. Specifically, as shown in FIG. 6, the divided substrate 3 is sequentially cleaved and separated along each of the multiple cleavage guide grooves 4 formed in the divided substrate 3, thereby producing multiple semiconductor laser elements 5, each having multiple waveguides 21.

[0070] Specifically, in the second cleavage step, a Teflon (registered trademark) blade is pressed into the surface of divided substrate 3 on the side of second main surface 12 of substrate 10 (i.e., the back surface) at the position opposite to cleavage guide groove 4. This causes a cleavage phenomenon to occur starting from cleavage guide groove 4, and divided substrate 3 is naturally cut and divided along the [1-100] direction shown by the dashed-dotted line in FIG. 6. This makes it possible to fabricate semiconductor laser devices 5 having multiple waveguides 21. The semiconductor laser devices 5 fabricated in this manner are bar-shaped laser device substrates.

[0071] In the second cleavage step, if debris 3D generated by laser scribing in the first dividing step is deposited on the back surface (the surface on the n-side electrode 40 side) of the divided substrate 3, the debris 3D will get in the way when the blade is pushed in. Therefore, as described above, in the first dividing step, laser scribing is performed on the front surface of the semiconductor laminated substrate 2 so that the debris 3D will be deposited on the front surface (the surface on the p-side electrode 30 side) of the semiconductor laminated substrate 2.

[0072] Furthermore, when the divided substrate 3 is cleaved to divide it into a plurality of semiconductor laser elements 5, the order in which the divided substrate 3 is cleaved may be sequential as shown in Figures 6 and 7A, but it is preferable to cleave the divided substrate 3 in the center as shown in Figure 7B. Cleaving the divided substrate 3 in the order of center cleavage distributes the mechanical force during cleavage evenly between the top and bottom, allowing the divided substrate 3 to be cleaved successfully as a whole.

[0073] In this way, debris 3D and 4D are deposited on the longitudinal ends of the semiconductor laser device 5 fabricated through the cleavage steps (first cleavage step and second cleavage step). Specifically, debris 3D and 4D are deposited on the surface of the semiconductor laser device 5 on the first main surface 11 side of the substrate 10. In other words, debris 3D and 4D are deposited on the surface of the semiconductor laser device 5 on the p-side electrode 30 side (front surface).

[0074] Therefore, after the cleaving steps (first cleaving step and second cleaving step), the semiconductor laser element 5 is divided (second dividing step) in order to remove the portions of the semiconductor laser element 5 where the debris 3D and 4D have accumulated.

[0075] In the second dividing step, one of the plurality of semiconductor laser elements 5 fabricated in the cleavage step is divided along the Y-axis direction, thereby removing at least one end of the semiconductor laser element 5 in the longitudinal direction.

[0076] In this embodiment, as shown in FIG. 8 , the cleavage guide grooves 4 remain at the end of the semiconductor laser element 5 on the first end facet 3a side, which is one of the longitudinal end faces, and debris 4D deposited during the formation of the cleavage guide grooves 4 is present around the cleavage guide grooves 4. Furthermore, the end of the semiconductor laser element 5 on the first end facet 3a side has laser scribe scratches (laser scribe grooves) formed in the first dividing step, and debris 3D deposited by the laser scribing is present near the first end facet 3a of the semiconductor laser element 5. Thus, the end of the semiconductor laser element 5 on the first end facet 3a side has debris 3D and 4D, cleavage guide grooves 4, and laser scribe scratches. Therefore, in the second dividing step, the end of the semiconductor laser element 5 on the first end facet 3a side is removed, thereby removing the debris 3D and 4D, as well as the cleavage guide grooves 4 and the laser scribe scratches.

[0077] 8, the end portion on the second end facet 3b side, which is the other end face in the longitudinal direction of the semiconductor laser element 5, does not have the cleavage guide grooves 4, but the laser scribe scratches formed in the first dividing step remain and debris 3D deposited by the laser scribing is present. Therefore, in the second dividing step, the debris 3D and the laser scribe scratches are removed by removing the end portion on the second end facet 3b side of the semiconductor laser element 5.

[0078] As described above, in this embodiment, not only the end portion on the first facet 3a side of the semiconductor laser element 5 but also the end portion on the second facet 3b side of the semiconductor laser element 5 are removed. In other words, both ends of the semiconductor laser element 5 in the longitudinal direction are removed.

[0079] Specifically, when removing the end portion on the first facet 3a side and the end portion on the second facet 3b side of the semiconductor laser element 5, first, as shown in Fig. 8, division grooves 6 are formed by laser scribing on the second main surface 12 side of the substrate 10 of the semiconductor laser element 5 (groove forming step). The division grooves 6 are grooves for dividing the semiconductor laser element 5.

[0080] In this groove forming step, the division grooves 6 are formed in the surface (back surface) of the semiconductor laser element 5 on the second main surface 12 side of the substrate 10 so as to extend along the Y-axis direction. In this embodiment, the division grooves 6 are formed in the semiconductor laser element 5 by laser scribing. Therefore, the division grooves 6 are laser scribed grooves formed by laser scribing.

[0081] In this way, by forming the division grooves 6 by laser scribing the back surface (the surface on the n-side electrode 40 side) of the semiconductor laser element 5, even if debris 6D is generated by laser scribing, the debris 6D accumulates on the back surface of the semiconductor laser element 5, and not on the front surface (the surface on the p-side electrode 30 side) of the semiconductor laser element 5. In this case, as shown in the enlarged view of FIG. 8 , by forming the division grooves 6 in the semiconductor laser element 5, debris 6D with a width of about 30 μm accumulates on both sides of the division grooves 6 on the back side of the semiconductor laser element 5. The debris 6D is processing waste of the semiconductor laser element 5 generated when the division grooves 6 are formed in the semiconductor laser element 5 by laser scribing. The debris 6D accumulates, for example, on the surface of the n-side electrode 40.

[0082] Furthermore, in this embodiment, the division groove 6 does not reach the third side surface 1c and the fourth side surface 1d formed in the semiconductor laser element 5 by the second cleavage step. That is, one end of the division groove 6 in the Y-axis direction is located at a position set back from the third side surface 1c, and the other end of the division groove 6 in the Y-axis direction is located at a position set back from the fourth side surface 1d. With this configuration, it is possible to prevent debris generated when forming the division groove 6 by laser scribing from adhering to the third side surface 1c and the fourth side surface 1d, which are the cavity end faces of the semiconductor laser element 5.

[0083] The depth of the division grooves 6 formed by laser scribing is approximately 50 μm from the surface (back surface) on the second main surface 12 side of the semiconductor laser element 5, and when viewed from above, the width of the division grooves 6 is approximately 5 μm and the length of the division grooves 6 is approximately 1100 μm.

[0084] In this embodiment, in order to remove both longitudinal end portions of the semiconductor laser element 5, the division grooves 6 are formed at the end portion on the first end facet 3a side and the end portion on the second end facet 3b side of the semiconductor laser element 1. Specifically, the division groove 6 at the end portion on the first end facet 3a side is formed at a position 600 μm from the first end facet 3a. The division groove 6 at the end portion on the second end facet 3b side is formed at a position 200 μm from the second end facet 3b.

[0085] Fig. 9 shows an SEM image after the division grooves 6 were formed. Fig. 9 shows a semiconductor laser element 5 in which the division grooves 6 were formed, and an SEM image of the cross section of the semiconductor laser element 5 taken along line AA. As shown in Fig. 9, when the division grooves 6 were formed to a depth of 50 µm, debris 6D with a height of 1 µm or less and a width of 30 µm accumulated around the division grooves 6.

[0086] Next, after forming the division grooves 6 in the semiconductor laser element 5 in the groove forming step, the semiconductor laser element 5 is divided along the division grooves 6, and the portions including the cleavage guide grooves 4 are removed.

[0087] Specifically, a Teflon (registered trademark) blade is pressed into a portion of the semiconductor laser element 5 on the surface on the first main surface 11 side of the substrate 10 (i.e., the front surface) opposite the division grooves 6. This causes the semiconductor laser element 5 to be cut along the division grooves 6. In this embodiment, the division grooves 6 are formed at both longitudinal end portions of the semiconductor laser element 1, so that, as shown in FIG. 10 , the semiconductor laser element 5 is cut at the two division grooves 6, and the end 5 a on the first facet 3 a side and the end 5 a on the second facet 3 b side of the semiconductor laser element 5 are separated and removed from the semiconductor laser element 5.

[0088] At this time, debris 3D and 4D and cleavage guide groove 4 are present at end 5a of semiconductor laser element 5 on the first facet 3a side, so by removing end 5a of semiconductor laser element 5 on the first facet 3a side, debris 3D and 4D and cleavage guide groove 4 are removed from semiconductor laser element 5. Also, debris 3D is present at end 5a of semiconductor laser element 5 on the second facet 3b side, so by removing end 5a of semiconductor laser element 5 on the second facet 3b side, debris 3D is removed from semiconductor laser element 5. Specifically, all of debris 3D and 4D and all of cleavage guide groove 4 are removed from semiconductor laser element 5. In this manner, the semiconductor laser element 1 shown in FIG. 1 can be fabricated.

[0089] An SEM image of the first side surface 1a of the semiconductor laser device 1 fabricated in this manner is shown in Fig. 11. Fig. 11 shows the semiconductor laser device 5 from which the end portion 5a has been removed, and a micrograph of the first side surface 1a of the semiconductor laser device 5 as viewed from direction B. As shown in the micrograph in Fig. 11, it can be seen that part of the dividing groove 6 remains on the first side surface 1a of the semiconductor laser device 1. This remaining part of the dividing groove 6 is the step portion 50 of the semiconductor laser device 1 shown in Figs. 1 and 2.

[0090] After removing the debris 3D and 4D and the cleavage guide groove 4, facet coating films are formed on the cavity facets of the semiconductor laser device 1 (facet coating step). For example, a facet coating film with a reflectance of 16% is formed on the third side face 1c, which is the front facet of the semiconductor laser device 1, and a facet coating film with a reflectance of 95% or more is formed on the fourth side face 1d, which is the rear facet of the semiconductor laser device 1. A dielectric multilayer film can be used as the facet coating film.

[0091] [Actions and effects] As described above, the manufacturing method of the semiconductor laser device 1 according to this embodiment includes: a first dividing step of dividing the substrate 10, on which the nitride-based semiconductor laser stack structure 20 having a plurality of waveguides 21 each extending in the Y-axis direction (first direction), along the Y-axis direction to produce a plurality of divided substrates 3, each having a plurality of waveguides 21; a cleaving step of cleaving one of the plurality of divided substrates 3 produced in the first dividing step along the X-axis direction (second direction) to produce a plurality of semiconductor laser devices 5, each having a plurality of waveguides 21; and a second dividing step of dividing one of the plurality of semiconductor laser devices 5 produced in the cleaving step along the Y-axis direction to remove at least one end of the semiconductor laser device 5 in the longitudinal direction (the second direction that is perpendicular to the waveguides 21). The cleavage process includes a first cleavage process for forming cleavage guide grooves 4 extending in the X-axis direction in the divided substrate 3, and a second cleavage process for cleaving the divided substrate 3 along the longitudinal direction of the cleavage guide grooves 4 (a second direction that is perpendicular to the waveguide 21). In the second division process, a portion including the cleavage guide grooves 4 is removed as one end of the semiconductor laser element 5 in the longitudinal direction.

[0092] This configuration makes it possible to remove scratches on the dividing interface that occur when dividing substrate 10 into divided substrates 3 in the first dividing step, and debris 3D that accumulates near the dividing interface. Furthermore, it is possible to remove cleavage guide grooves 4 (grooves for dividing) that are formed when dividing divided substrates 3 into semiconductor laser elements 5 in the cleavage step, and it is also possible to remove debris 4D that accumulates around cleavage guide grooves 4 when forming cleavage guide grooves 4. This makes it possible to obtain semiconductor laser element 1 that is free of cleavage guide grooves 4 and debris 3D and 4D in the mounting area when semiconductor laser element 1 is mounted on a submount or the like. This makes it possible to prevent problems from occurring when semiconductor laser element 1 is mounted on a submount or the like.

[0093] In the method for manufacturing semiconductor laser device 1 according to the present embodiment, cleavage guide grooves 4 are formed in the surface (front surface) of divided substrate 3 that faces first main surface 11 of substrate 10 in the first cleavage step of the cleavage process.

[0094] This configuration allows cleavage guide grooves 4 to be formed in accurate alignment with the shape (i.e., mask pattern) of nitride-based semiconductor laser stack structure 20 formed on first main surface 11 of substrate 10. This allows waveguide 21 to be formed at a predetermined position with high precision.

[0095] Furthermore, in the manufacturing method of the semiconductor laser element 1 according to this embodiment, in the groove forming step of forming the division grooves 6 by laser scribing, the division grooves 6 are formed on the surface (back surface) of the semiconductor laser element 5 on the second main surface 12 side, and in the second dividing step, the semiconductor laser element 5 is divided along the division grooves 6 to remove the portion including the cleavage guide grooves 4.

[0096] In this way, by forming the division grooves 6 for removing the cleavage guide grooves 4 and the debris 3D and 4D on the back surface of the semiconductor laser device 5, the cleavage guide grooves 4 and the debris 3D and 4D do not remain on the front surface (the surface on the p-side electrode 30 side), which serves as the mounting surface of the semiconductor laser device 1. This allows the semiconductor laser device 1 to be easily mounted on a submount or the like by junction-down mounting with the p-side electrode 30 facing downward.

[0097] Furthermore, in the manufacturing method of the semiconductor laser element 1 according to this embodiment, in the groove forming step, the dividing groove 6 is formed so as to extend along the Y-axis direction, and the dividing groove 6 does not reach the third side surface 1c formed in the semiconductor laser element 5 by the second cleavage step.

[0098] This configuration makes it possible to prevent debris 6D, which is generated when forming the division grooves 6 by laser scribing, from adhering to the third side surface 1c, which is the cavity end face of the semiconductor laser element 5.

[0099] Furthermore, if the division grooves 6 were formed so as to reach the third side surface 1c of the semiconductor laser element 5, the resin sheet on which the semiconductor laser element 5 is placed would also be cut when forming the division grooves 6 by laser scribing or the like, and there is a risk that debris scattered from the resin sheet due to this cutting would adhere to the third side surface 1c of the semiconductor laser element 5. In contrast, by forming the division grooves 6 so as not to reach the third side surface 1c of the semiconductor laser element 5 as in the present embodiment, it is possible to prevent debris from scattering from the resin sheet and to prevent debris scattered from the resin sheet from adhering to the third side surface 1c of the semiconductor laser element 5.

[0100] Furthermore, in the method for manufacturing the semiconductor laser device 1 according to this embodiment, the division grooves 6 do not even reach the fourth side surface 1d of the semiconductor laser device 5.

[0101] This configuration makes it possible to prevent debris 6D generated when forming the division grooves 6 by laser scribing from adhering to the fourth side surface 1d, which is the cavity end face of the semiconductor laser element 5. Furthermore, it is also possible to prevent debris scattered from the resin sheet on which the semiconductor laser element 5 is placed when forming the division grooves 6 by laser scribing or the like from adhering to the fourth side surface 1d of the semiconductor laser element 5.

[0102] Furthermore, according to the manufacturing method of the semiconductor laser device 1 according to this embodiment, the first side surface 1a and the second side surface 1b of the semiconductor laser device 1 can be formed at any position by the dividing groove 6, and therefore the distance between the waveguide 21 and the first side surface 1a or the second side surface 1b of the semiconductor laser device 1 can also be set arbitrarily and accurately.

[0103] In this case, in the semiconductor laser device 1 manufactured by the manufacturing method of the semiconductor laser device 1 according to the embodiment, if the shortest distance between two adjacent waveguides 21 is defined as a first distance d1 and the distance between the waveguide 21 closest to the first side surface 1a among the multiple waveguides 21 and the first side surface 1a is defined as a second distance d2, the second distance d2 is wider than the first distance d1.

[0104] This configuration makes it possible to obtain a semiconductor laser device 1 with excellent heat dissipation characteristics. This point will be explained in comparison with a semiconductor laser device 1X of a comparative example using FIGS. 12A and 12B. FIG. 12A is a diagram showing a state in which the semiconductor laser device 1X of the comparative example is mounted on a heat sink in a junction-down manner. FIG. 12B is a diagram showing a state in which the semiconductor laser device 1 according to the embodiment is mounted on a heat sink in a junction-down manner. In FIGS. 12A and 12B, the circle surrounded by a dashed line indicates the spread of heat centered on the emitter corresponding to the waveguide 21.

[0105] 12A, in the semiconductor laser device 1X of the comparative example, the distance between the waveguide 21 closest to the side surface among the multiple waveguides 21 and the side surface is narrower than the pitch of the waveguides 21. Therefore, when the semiconductor laser device 1X is mounted junction-down on a submount, which serves as a heat sink, the waveguide 21 closest to the side surface in the longitudinal direction has a narrower heat dissipation path than the other waveguides 21. In other words, if the waveguide 21 located at the outermost end is too close to the side surface in the longitudinal direction of the semiconductor laser device 1X, the heat dissipation path of the waveguide 21 located at the outermost end is restricted. As a result, the waveguide 21 closest to the side surface in the longitudinal direction is more susceptible to deterioration over time than the other waveguides 21, which causes deterioration of the characteristics of the entire semiconductor laser device 1X.

[0106] In contrast, in the semiconductor laser device 1 according to this embodiment, the second interval d2 is wider than the first interval d1. That is, the distance between the waveguide 21 closest to the first side surface 1a among the multiple waveguides 21 and the first side surface 1a is wider than the pitch of the waveguides 21. As a result, as shown in FIG. 12B , when the semiconductor laser device 1 according to this embodiment is mounted junction-down on a submount, which serves as a heat sink, the waveguide 21 closest to the first side surface 1a can be located farther from the first side surface 1a than the other waveguides 21, ensuring a sufficiently wide heat dissipation path. This allows the semiconductor laser device 1 as a whole to have excellent heat dissipation characteristics, and prevents problems from occurring when the device is mounted on a submount or the like. In particular, this prevents problems from occurring when the semiconductor laser device 1 is mounted junction-down.

[0107] Furthermore, in the semiconductor laser element 1 according to this embodiment, if the distance between the waveguide 21 closest to the second side surface 1b among the plurality of waveguides 21 and the second side surface 1b is defined as a third distance d3, the third distance d3 is also wider than the first distance d1.

[0108] This makes it possible to ensure a sufficiently wide heat dissipation path for each of the waveguides 21 at both ends in the longitudinal direction of the semiconductor laser device 1. This makes it possible to obtain a semiconductor laser device 1 with excellent heat dissipation characteristics as a whole.

[0109] [Modification of semiconductor laser element] In the above embodiment, the n-side electrode 40 is formed on the entire back surface of the semiconductor laser device 1, and the second region 120 and the third region 130 are regions that do not function as a semiconductor laser by not forming the waveguide 21 in the second region 120 and the third region 130, but this is not limited to this. For example, as shown in Fig. 13, the second region 120 and the third region 130 may be regions that do not function as a semiconductor laser by not forming the n-side electrode 40 in the second region 120 and the third region 130. Fig. 13 is a diagram showing the configuration of a semiconductor laser device 5A (1A) according to a modified example.

[0110] In this case, the semiconductor laser element 5A(1A) according to this modification can be fabricated by the same method as the semiconductor laser element 5(1) in the above embodiment. In this case, also in this modification, as in the above embodiment, the division grooves 6 are formed on the back surface of the semiconductor laser element 5A rather than on the front surface, so that debris 6D generated when forming the division grooves 6 by laser scribing is not present on the front surface of the semiconductor laser element 5A.

[0111] However, because the division grooves 6 are formed on the back surface of the semiconductor laser element 5A, debris 6D generated when forming the division grooves 6 ends up being deposited on the back surface (the surface on the second main surface 12 side) of the semiconductor laser element 5A. Specifically, the debris 6D deposits around the division grooves 6, that is, on the second main surface 12 of the substrate 10 in the second region 120 and the third region 130 near the first side surface 1a and the second side surface 1b where the n-side electrode 40 is not formed.

[0112] Therefore, in the semiconductor laser device 5A (1A) of this modification, the thickness of the n-side electrode 40 formed inside the region where the debris 6D has accumulated is made thicker than the height of the debris 6D. As an example, since the height of the debris 6D is 1 μm at most, the thickness of the n-side electrode 40 is 1 μm or more, and more preferably 2 μm or more.

[0113] In this case, the n-side electrode 40 is preferably provided at a position sufficiently distant from the division groove 6 and the debris 6D (for example, at a position 30 μm or more away from the division groove 6). This makes it possible to prevent the debris 6D from accumulating on the surface of the n-side electrode 40.

[0114] In this way, by forming the n-side electrode 40 away from the position where the debris 6D accumulates and making the thickness of the n-side electrode 40 thicker than the height of the debris 6D, it is possible to prevent the debris 6D accumulated on the back surface of the semiconductor laser element 1A from becoming an obstacle when it is desired to connect the n-side electrode 40 side to a heat sink or the like to improve heat dissipation performance.

[0115] [Semiconductor laser device] Next, a semiconductor laser device using the semiconductor laser element 1 according to the embodiment will be described.

[0116] First, a first semiconductor laser device 200 including a semiconductor laser element 1 according to the embodiment will be described with reference to Fig. 14. Fig. 14 is a diagram showing the configuration of the first semiconductor laser device 200 according to the embodiment.

[0117] As shown in FIG. 14, a first semiconductor laser device 200 according to this embodiment includes the above-described semiconductor laser element 1 and a submount 210 on which the semiconductor laser element 1 is mounted.

[0118] The submount 210 includes a base 211 and an electrode layer 212 laminated on the upper surface of the base 211. The base 211 is preferably made of a material with high thermal conductivity and a small thermal expansion coefficient. Examples of materials that can be used for the base 211 include SiC ceramic, AlN ceramic, semi-insulating SiC crystal, and artificial diamond. The base 211 may also be made of a metal material such as a Cu-W alloy or a Cu-Mo alloy. The electrode layer 212 is made of, for example, Ti / Pt / Au in that order from the base 211 side.

[0119] In this embodiment, the semiconductor laser device 1 is 1 Main surface of 11 The semiconductor laser device 1 is mounted on the submount 210 with the p-side electrode 30 formed on the front surface facing the submount 210. In other words, the semiconductor laser device 1 is disposed with the p-side electrode 30 formed on the front surface facing the submount 210, and is mounted on the submount 210 in a junction-down manner.

[0120] The semiconductor laser device 1 is mounted on the submount 210 via a bonding layer 220. In this embodiment, the semiconductor laser device 1 is electrically connected to the electrode layer 212 of the submount 210. Therefore, the bonding layer 220 is made of a metal bonding material such as AuSn solder.

[0121] As described above, according to the first semiconductor laser device 200, since the above-described semiconductor laser element 1 is used, the semiconductor laser element 1 can be mounted on the submount 210 without causing any problems during mounting.

[0122] Next, a second semiconductor laser device 201 including the semiconductor laser element 1 according to the embodiment will be described with reference to Fig. 15. Fig. 15 is a diagram showing the configuration of the second semiconductor laser device 201 according to the embodiment.

[0123] 15, the second semiconductor laser device 201 according to this embodiment includes the semiconductor laser element 1, a submount 210 on which the semiconductor laser element 1 is mounted, and a heat sink 230. That is, the second semiconductor laser device 201 has a configuration in which the heat sink 230 is further included in the first semiconductor laser device 200 shown in FIG.

[0124] Specifically, the submount 210 on which the semiconductor laser element 1 is mounted in a submount mounting process is placed on a heat sink 230 in a heat sink mounting process. The heat sink 230 may be, for example, a water-cooled heat sink made of Cu. The submount 210 on which the semiconductor laser element 1 is mounted is bonded to the upper surface of the heat sink 230 using, for example, a bonding material 240. The bonding material 240 may be, for example, a conductive bonding material with high thermal conductivity, such as SnAgCu solder (SAC solder).

[0125] The second semiconductor laser device 201 according to this embodiment has a heat sink 230 as a positive electrode, and further includes a negative electrode 260 provided on the heat sink 230 via an insulating layer 250, a first metal wire 270, and a second metal wire 280.

[0126] Specifically, a wire bonding process is performed to connect the electrode layer 212 of the submount 210 to the heat sink 230 with a plurality of first metal wires 270. Furthermore, the n-side electrode 40 of the semiconductor laser device 1 is connected to the negative electrode 260 with a plurality of second metal wires 280. For example, gold wires can be used as the first metal wires 270 and the second metal wires 280. Furthermore, a Cu block can be used as the negative electrode 260. Note that if the base 211 of the submount 210 is made of a metal or the like and has conductivity, the first metal wires 270 are not necessary.

[0127] As described above, according to the second semiconductor laser device 201, the semiconductor laser element 1 is thermally connected to the heat sink 230, so that the heat generated in the semiconductor laser element 1 can be efficiently dissipated. This makes it possible to realize a semiconductor laser device capable of high-power operation.

[0128] Next, a third semiconductor laser device 202 including the semiconductor laser element 1 according to the embodiment will be described with reference to Fig. 16. Fig. 16 is a diagram showing the configuration of the third semiconductor laser device 202 according to the embodiment.

[0129] 16, a third semiconductor laser device 202 according to this embodiment includes a plurality of second semiconductor laser devices 201 shown in FIG. 15. Specifically, the third semiconductor laser device 202 can be fabricated by stacking second semiconductor laser devices 201 with heat sinks 230 by a stacking process. In this case, the heat sink 230 (positive electrode) of the upper second semiconductor laser device 201 is electrically connected to the negative electrode 260 of the lower second semiconductor laser device 201. In other words, the two semiconductor laser elements 1 in the upper and lower second semiconductor laser devices 201 are electrically connected in series.

[0130] In this embodiment, two second semiconductor laser devices 201 are stacked, but the present invention is not limited to this. For example, three or more second semiconductor laser devices 201 may be stacked. In other words, the second semiconductor laser devices 201 may be stacked in order.

[0131] As described above, the third semiconductor laser device 202 uses a plurality of the second semiconductor laser devices 201 shown in FIG. 15, and therefore can easily obtain a large optical output.

[0132] Next, a fourth semiconductor laser device 203 including the semiconductor laser element 1 according to the embodiment will be described with reference to Fig. 17. Fig. 17 is a diagram showing the configuration of the fourth semiconductor laser device 203 according to the embodiment.

[0133] As shown in Figure 17, the fourth semiconductor laser device 203 according to this embodiment has a configuration in which, in the second semiconductor laser device 201 shown in Figure 15, the second metal wire 280 is replaced with a heat sink 290 on which an electrode layer 291 is formed.

[0134] The heat sink 290 functions as a heat sink. Therefore, it is preferable that the heat sink 290 is made of a material with high thermal conductivity. The electrode layer 291 is formed on the surface of the heat sink 290. The electrode layer 291 is, for example, an Au layer. The electrode layer 291 is electrically connected to the n-side electrode 40 of the semiconductor laser device 1 by a conductive bonding material such as AuSn solder. In addition, the electrode layer 291 and the negative electrode 260 are electrically connected by solder bumps. The use of solder bumps not only electrically bonds the electrode layer 291 and the negative electrode 260 but also absorbs the height difference between the heat sink 290 and the negative electrode 260.

[0135] 15, the fourth semiconductor laser device 203 has an additional heat dissipation path for heat generated in the semiconductor laser element 1 by the heat sink 290. This makes it possible to realize a semiconductor laser device capable of higher output operation.

[0136] 1, debris 6D accumulates on the n-side electrode 40 when the division grooves 6 are formed by laser scribing, and this debris 6D may get in the way when bonding the heat sink 290. Therefore, in the fourth semiconductor laser device 203, rather than using the semiconductor laser element 1 shown in Fig. 1, it is better to use the semiconductor laser element 1A shown in Fig. 13, which has an n-side electrode 40 that is thicker than the height of the debris 6D at a position away from the position where the debris 6D accumulates.

[0137] (Variation) The method for manufacturing a semiconductor laser element, the semiconductor laser element, and the semiconductor laser device according to the present disclosure have been described above based on the embodiments, but the present disclosure is not limited to the above-described embodiments.

[0138] For example, in the above embodiment, in the semiconductor laser device 1 having a longitudinal width of 9200 μm and a length in the cavity length direction of 1200 μm, 21 waveguides 21 each having a width of 30 μm are formed at intervals of 400 μm, but this is not limited thereto. Specifically, in a semiconductor laser having a longitudinal width of 9200 μm and a length in the cavity length direction of 1200 μm, 37 waveguides 21 each having a width of 30 μm may be formed at intervals of 225 μm (= d1). In this case, the second interval d2 and the third interval d3 are, for example, d2 = d3 = 550 μm.

[0139] Alternatively, in a semiconductor laser having a longitudinal width of 9200 μm and a length in the cavity length direction of 1200 μm, 56 waveguides 21 each having a width of 30 μm may be formed at intervals of 150 μm (= d1). In this case, the second interval d2 and the third interval d3 are, for example, d2=d3=475 μm.

[0140] Furthermore, the spacing between the plurality of waveguides 21 and the widths of the plurality of waveguides do not all have to be the same. The width and arrangement of each waveguide are determined according to the design output of the semiconductor laser element and the design of the heat dissipation circuit.

[0141] In the above embodiment, the second region 120 and the third region 130 are regions that do not function as semiconductor lasers by not forming the waveguide 21 in the second region 120 and the third region 130, but this is not limiting. For example, even if the p-side electrode 30 and the waveguide 21 are formed in the second region 120 and the third region 130, the second region 120 and the third region 130 may be regions that do not function as semiconductor lasers by having a structure in which the p-side electrode 30 and the waveguide 21 are separated by an insulating film and are not electrically connected to each other.

[0142] In the above embodiment, the waveguide 21 in the semiconductor laser device 1 has a ridge stripe structure, but this is not limiting. For example, the waveguide 21 may have an electrode stripe structure formed only by divided electrodes without forming a ridge stripe, or may have a current confinement structure using a current blocking layer.

[0143] In the above embodiment, the longitudinal direction of the semiconductor laser device 1 has been described as being perpendicular to the waveguides 21. However, when the number of waveguides is small, the longitudinal direction may be parallel to the laser cavity length. For example, a semiconductor laser device 1 can be formed in which two waveguides 21, each 1200 μm long in the cavity length direction, are formed at an interval (= d1) of 150 μm, and the second interval d2 and third interval d3 are 475 μm outside each of the two waveguides 21. In this case, the length in the cavity length direction (1200 μm) is greater than the width of the semiconductor laser device (1100 μm) (475 μm + 150 μm + 475 μm).

[0144] Furthermore, if the spacing between the waveguides 21 of the semiconductor laser device 1 is appropriate and a heat sink with good heat dissipation and a cooling mechanism for it are provided, the total optical output of the semiconductor laser device 1 can be close to the optical output that can be extracted from one waveguide 21 multiplied by the number of waveguides. For example, in a semiconductor laser device having a maximum of 60 waveguides or less, a semiconductor laser with a wavelength of 365 nm to 390 nm can achieve an output of 60 W to 300 W, a semiconductor laser with a wavelength of 390 nm to 420 nm can achieve an output of 180 W to 600 W, a wavelength of 420 nm to 460 nm can achieve an output of 360 W to 900 W, and a wavelength of 460 nm to 500 nm can achieve an output of 180 W to 900 W.

[0145] Furthermore, in the semiconductor laser device 1 of the above embodiment, a case where a nitride-based semiconductor material is used has been exemplified, but this is not limiting. For example, the present invention can be applied to a case where a semiconductor material other than a nitride-based semiconductor material is used. In this case, the semiconductor laser device 1 will have a semiconductor laser stack structure using another semiconductor material, rather than the nitride-based semiconductor laser stack structure 20.

[0146] Furthermore, in the above embodiment, a case has been described where a semiconductor laser element that is a laser bar having a plurality of waveguides 21 is manufactured. However, the semiconductor laser element 1 that is a laser bar having a plurality of waveguides 21 may be further divided into a plurality of pieces to produce single-emitter semiconductor laser elements each having one waveguide 21.

[0147] In addition, this disclosure also includes forms obtained by making various modifications to the embodiments that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions of each embodiment within the scope of the present disclosure. [Industrial Applicability]

[0148] The semiconductor laser element of the present disclosure is useful as a light source for various applications, such as a light source for image display devices such as projectors and displays, a light source for in-vehicle headlamps, a light source for lighting devices, or a light source for various industrial equipment such as laser welding devices, thin film annealing devices, and laser processing devices. [Explanation of symbols]

[0149] 1, 1A, 5, 5A semiconductor laser element 1a First aspect 1b The second aspect 1c The third aspect 1d. The Fourth Aspect 2. Semiconductor multilayer substrate 2a PCM area 3-division board 3D, 4D, 6D debris 3a First end face 3b Second end face 4 Cleavage introduction groove 5a end 6 dividing groove 10 Substrate 11 first main surface 12 Second main surface 20. Nitride-based semiconductor laser stack structure 21 Waveguide 30 p side electrode 40 n-side electrode 50 Step 110 First Area 120 Second Area 130 The Third Region 200 First semiconductor laser device 201 Second semiconductor laser device 202 Third semiconductor laser device 203 Fourth Semiconductor Laser Device 210 Submount 211 Base 212 Electrode layer 220 Bonding layer 230 Heatsink 240 Bonding material 250 insulating layer 260 negative electrode 270 First metal wire 280 Second metal wire 290 Heat sink 291 Electrode layer

Claims

1. A method for manufacturing a semiconductor laser device having a plurality of waveguides, comprising: a first dividing step of dividing a substrate, on which a nitride-based semiconductor laser stacked structure has been formed, the nitride-based semiconductor laser stacked structure having the plurality of waveguides each extending in a first direction parallel to a first main surface, along the first direction to produce a plurality of divided substrates, each divided substrate having the plurality of waveguides arranged at intervals in a second direction perpendicular to the first direction and parallel to the first main surface; a cleaving step of cleaving one of the plurality of divided substrates produced in the first dividing step along the second direction to produce a plurality of semiconductor laser elements, each having a plurality of the waveguides; a second dividing step of dividing one of the plurality of semiconductor laser elements fabricated in the cleaving step along the first direction to remove at least one end of the semiconductor laser element in the second direction, the cleaving step includes a first cleaving step of forming cleavage guide grooves in the divided substrates, the cleavage guide grooves extending in the second direction, and a second cleaving step of cleaving the divided substrates along the second direction using the cleavage guide grooves; In the second dividing step, a portion including the cleavage guide groove is removed as one end of the semiconductor laser element in the second direction. A method for manufacturing a semiconductor laser element.

2. A method for manufacturing a semiconductor laser device having a plurality of waveguides, comprising: a first dividing step of dividing a substrate, on which a nitride-based semiconductor laser stacked structure has been formed, the nitride-based semiconductor laser stacked structure having the plurality of waveguides each extending in a first direction parallel to a first main surface, along the first direction to produce a plurality of divided substrates, each divided substrate having the plurality of waveguides arranged at intervals in a second direction perpendicular to the first direction and parallel to the first main surface; a cleaving step of cleaving one of the plurality of divided substrates produced in the first dividing step along the second direction to produce a plurality of semiconductor laser elements, each having a plurality of the waveguides; a second dividing step of dividing one of the plurality of semiconductor laser elements fabricated in the cleaving step along the first direction to remove at least one end of the semiconductor laser element in the second direction, the cleaving step includes a first cleaving step of forming cleavage guide grooves in the divided substrates, the cleavage guide grooves extending in the second direction, and a second cleaving step of cleaving the divided substrates along the second direction using the cleavage guide grooves; In the second dividing step, a portion including the cleavage guide groove is removed as one end of the semiconductor laser element in the second direction; the semiconductor laser element has a first side surface parallel to the first direction and a second side surface opposite to the first side surface, In the semiconductor laser element, the shortest distance between two adjacent waveguides is defined as a first distance, and the distance between the first side surface and one of the plurality of waveguides that is closest to the first side surface is defined as a second distance. The second distance is wider than the first distance. A method for manufacturing a semiconductor laser element.

3. the semiconductor laser element has a first region in which a plurality of the waveguides are formed, and a second region sandwiched between the first region and the first side surface and having the second gap; The second region is a region that does not function as a semiconductor laser. The method for manufacturing a semiconductor laser device according to claim 2 .

4. In the semiconductor laser element, when a distance between the second side surface and one of the plurality of waveguides that is closest to the second side surface is defined as a third distance, the third distance is wider than the first distance. The method for manufacturing a semiconductor laser device according to claim 3 .

5. the semiconductor laser element has a first side surface parallel to the first direction and a second side surface opposite to the first side surface, In the semiconductor laser element, when the shortest distance between two adjacent waveguides is defined as a first distance, and the distance between the first side surface and one of the plurality of waveguides that is closest to the first side surface is defined as a second distance, the second distance is wider than the first distance; In the semiconductor laser element, when a distance between the second side surface and one of the plurality of waveguides that is closest to the second side surface is defined as a third distance, the third distance is wider than the first distance. The method for manufacturing a semiconductor laser device according to claim 1 .

6. the semiconductor laser element has a third region that is a region sandwiched between the first region and the second side surface and has the third gap; The third region is a region that does not function as a semiconductor laser.

5. The method for manufacturing a semiconductor laser device according to claim 4.

7. The cleaving step includes a first cleaving step of forming cleavage guide grooves in the second region, the cleavage guide grooves extending in the second direction, and a second cleaving step of cleaving the divided substrates along the second direction of the cleavage guide grooves.

7. The method for manufacturing a semiconductor laser device according to claim 3, 4 or 6.

8. The cleavage guide groove does not reach the waveguide that is closest to the first side surface among the plurality of waveguides in the first region. The method for manufacturing a semiconductor laser device according to claim 7 .

9. the cleavage guide grooves are formed by laser scribing.

9. The method for manufacturing a semiconductor laser device according to claim 1, 7, or 8.

10. The flatness of a third side surface parallel to the second direction formed in the semiconductor laser element by the second cleavage step is higher than the flatness of a first side surface parallel to the first direction formed in the semiconductor laser element by the first division step and the flatness of a second side surface opposite to the first side surface.

10. The method for manufacturing a semiconductor laser device according to claim 1, or any one of claims 7 to 9.

11. the substrate has the first main surface on which the nitride-based semiconductor laser stacked structure is formed, and a second main surface opposite to the first main surface; a second dividing step of dividing one of the plurality of semiconductor laser elements fabricated by the cleaving step along the first direction to remove at least one end of the semiconductor laser element in the second direction; a groove forming step of forming division grooves on a surface of the semiconductor laser element on the second principal surface side by laser scribing, In the second dividing step, the semiconductor laser element is divided along the dividing grooves to remove the portion including the cleavage guide grooves. The method for manufacturing a semiconductor laser device according to any one of claims 1 and 7 to 10.

12. The substrate has the first main surface on which the nitride-based semiconductor laser stack structure is formed and a second main surface opposite to the first main surface, a groove forming step of forming division grooves on the second main surface side of the semiconductor laser element by laser scribing, In the second dividing step, the semiconductor laser element is divided along the dividing grooves to remove the portion including the cleavage guide grooves. The method for manufacturing a semiconductor laser device according to any one of claims 2 to 6.

13. In the groove forming step, the dividing grooves are formed so as to extend along the first direction, The division groove does not reach a third side surface parallel to the second direction formed in the semiconductor laser element by the second cleavage step.

13. The method for manufacturing a semiconductor laser device according to claim 11 or 12.

14. In the groove forming step, debris generated by the laser scribing when forming the division grooves is deposited on the second main surface side of the semiconductor laser element, an electrode is formed on the semiconductor laser element on the inner side of the region where the debris is accumulated; The thickness of the electrode is greater than the height of the debris. The method for manufacturing a semiconductor laser device according to any one of claims 11 to 13.

15. In the first dividing step, the substrate on which the nitride semiconductor laser stacked structure is formed is divided by laser scribing. The method for manufacturing a semiconductor laser device according to any one of claims 1 to 14.

16. A semiconductor laser element, a substrate having a first main surface and a second main surface opposite the first main surface; a nitride-based semiconductor laser stacked structure formed above the first main surface of the substrate and having a plurality of waveguides extending in a first direction parallel to the first main surface, the semiconductor laser element has a first side surface orthogonal to the first main surface and parallel to the first direction, a second side surface opposite to the first side surface, and a third side surface orthogonal to the first main surface and orthogonal to the first direction; the semiconductor laser element has a first region in which a plurality of the waveguides are formed, and a second region sandwiched between the first region and the first side surface, When the semiconductor laser element is viewed from the first direction, a step portion recessed inward from a surface of the semiconductor laser element on the second main surface side is formed on the first side surface, the third side surface is a cleavage plane; The flatness of the third side surface is higher than the flatness of each of the first side surface and the second side surface. Semiconductor laser element.

17. The step portion does not reach the third side surface.

17. The semiconductor laser device according to claim 16.

18. A semiconductor laser element, a substrate having a first main surface and a second main surface opposite the first main surface; a nitride-based semiconductor laser stacked structure formed above the first main surface of the substrate and having a plurality of waveguides extending in a first direction parallel to the first main surface, the semiconductor laser element has a first side surface orthogonal to the first main surface and parallel to the first direction, a second side surface opposite to the first side surface, and a third side surface orthogonal to the first main surface and orthogonal to the first direction; the semiconductor laser element has a first region in which a plurality of the waveguides are formed, and a second region sandwiched between the first region and the first side surface, the shortest distance between two adjacent waveguides is defined as a first distance, and the distance between the first side surface and one of the plurality of waveguides that is closest to the first side surface is defined as a second distance, the second distance being wider than the first distance; the third side surface is a cleavage plane; The flatness of the third side surface is higher than the flatness of each of the first side surface and the second side surface. Semiconductor laser element.

19. the semiconductor laser element has a third region sandwiched between the first region and the second side surface, a third distance between the second side surface and one of the plurality of waveguides that is closest to the second side surface, the third distance being wider than the first distance; 19. The semiconductor laser device according to claim 18.

20. an electrode is formed on the second main surface side, inside a region where debris has accumulated; The thickness of the electrode is greater than the height of the debris. The semiconductor laser device according to any one of claims 16 to 19.

21. a semiconductor laser element according to any one of claims 16 to 19; a submount on which the semiconductor laser element is mounted, The semiconductor laser element is mounted on the submount with the first main surface facing the submount. Semiconductor laser device.

22. Furthermore, a heat sink is provided, the submount is disposed on the heat sink; 22. The semiconductor laser device according to claim 21.

23. A method for manufacturing a semiconductor laser device having a plurality of waveguides, comprising: a cleaving step of cleaving one of a plurality of divided substrates, each having a plurality of the waveguides extending in a first direction parallel to a first principal surface, along a second direction orthogonal to the first direction and parallel to the first principal surface, to fabricate a plurality of semiconductor laser elements, each having a plurality of the waveguides; a dividing step of dividing one of the plurality of semiconductor laser elements fabricated in the cleaving step along the first direction to remove at least one end of the semiconductor laser element in the second direction, the cleaving step includes a first cleaving step of forming cleavage guide grooves in the divided substrates, the cleavage guide grooves extending in the second direction, and a second cleaving step of cleaving the divided substrates along the second direction using the cleavage guide grooves; In the dividing step, a portion including the cleavage guide groove is removed as one end of the semiconductor laser element in the second direction. A method for manufacturing a semiconductor laser element.

24. A method for manufacturing a semiconductor laser device having a plurality of waveguides, comprising: a cleaving step of cleaving one of a plurality of divided substrates, each having a plurality of the waveguides extending in a first direction parallel to a first principal surface, along a second direction orthogonal to the first direction and parallel to the first principal surface, to fabricate a plurality of semiconductor laser elements, each having a plurality of the waveguides; a dividing step of dividing one of the plurality of semiconductor laser elements fabricated in the cleaving step along the first direction to remove at least one end of the semiconductor laser element in the second direction, the cleaving step includes a first cleaving step of forming cleavage guide grooves in the divided substrates, the cleavage guide grooves extending in the second direction, and a second cleaving step of cleaving the divided substrates along the second direction using the cleavage guide grooves; In the dividing step, a portion including the cleavage guide groove is removed as one end of the semiconductor laser element in the second direction; the semiconductor laser element has a first side surface parallel to the first direction and a second side surface opposite to the first side surface, In the semiconductor laser element, the shortest distance between two adjacent waveguides is defined as a first distance, and the distance between the first side surface and one of the plurality of waveguides that is closest to the first side surface is defined as a second distance. The second distance is wider than the first distance. A method for manufacturing a semiconductor laser element.

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