Manufacturing method for semiconductor laser devices

Abstract

The present invention provides a semiconductor laser element that is easy to inspect and a method for manufacturing a semiconductor laser element. [Solution] A method for manufacturing a semiconductor laser element, comprising: preparing a semiconductor laminate having a first window structure, comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer between the first conductive semiconductor layer and the second conductive semiconductor layer; forming a first electrode on the second conductive semiconductor layer having a first opening at a position away from the first window structure in a first direction that will become the direction of the resonator after piecewise separation, when viewed from above; and performing a first visual inspection using a virtual line based on the first opening.

Description

Technical Field

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[0001] The present disclosure relates to a method for manufacturing a semiconductor laser device.

Background Art

[0002] A semiconductor laser device that emits red or infrared laser light may form a window structure on the laser light emission end face to improve resistance to COD (Catastrophic Optical Damage). Patent Document 1 discloses a semiconductor laser device having a window structure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The vicinity of the window structure may discolor. The end of the electrode disposed on the window structure and the end face of the semiconductor laser device become difficult to observe due to this discoloration. At this time, there is a risk of affecting the determination of the inspection of the semiconductor laser device. Even if a window structure is provided, an electrode structure that enables easy inspection is required.

[0005] An embodiment of the present disclosure aims to provide a method for manufacturing a semiconductor laser device that enables easy inspection.

Means for Solving the Problems

[0006] A method for manufacturing a semiconductor laser element according to one embodiment of the present disclosure includes preparing a semiconductor laminate having a first window structure, comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer between the first conductive semiconductor layer and the second conductive semiconductor layer; forming a first electrode having a first opening on the second conductive semiconductor layer at a position away from the first window structure in a first direction that will become the direction of the resonator after piecewise separation, when viewed from above; and performing a first visual inspection using a virtual line based on the first opening. [Effects of the Invention]

[0007] According to one embodiment of this disclosure, a method for manufacturing a semiconductor laser element that is easy to inspect can be provided. [Brief explanation of the drawing]

[0008] [Figure 1A] This is a schematic top view of a wafer comprising multiple semiconductor stacks. [Figure 1B] This is a schematic top view illustrating the process of preparing a semiconductor stack. [Figure 1C] Figure 1B is a cross-sectional view of the IC-IC line. [Figure 1D] Figure 1B is a cross-sectional view along the ID-ID line. [Figure 2A] This is a schematic top view illustrating the process of forming the first mask. [Figure 2B] Figure 2A is a cross-sectional view along the IIB-IIB line. [Figure 3A] This is a schematic top view illustrating the process of forming the first electrode. [Figure 3B] Figure 3A is a cross-sectional view along the line IIIB-IIIB. [Figure 4A] This is a schematic top view illustrating the process of removing the first mask. [Figure 4B] Figure 4A is a cross-sectional view along the IVB-IVB line. [Figure 5A] This is a schematic top view illustrating the process of forming the second mask. [Figure 5B] Figure 5A is a cross-sectional view along the VB-VB line. [Figure 6A] It is a schematic top view showing the step of forming the second electrode. [Figure 6B] It is a cross-sectional view taken along the line VIB-VIB in FIG. 6A. [Figure 7A] It is a schematic top view showing the step of removing the second mask. [Figure 7B] It is a cross-sectional view taken along the line VIIB-VIIB in FIG. 7A. [Figure 8] It is a schematic cross-sectional view of a semiconductor laser element.

Embodiments for Carrying Out the Invention

[0009] In this specification, the term "step" includes not only an independent step but also a step whose purpose can be achieved even if it cannot be clearly distinguished from other steps. Hereinafter, embodiments of the present invention will be described in detail. However, the embodiments shown below are examples of a semiconductor laser element and a method for manufacturing the same for embodying the technical idea of the present invention, and the present invention is not limited to the semiconductor laser element and the method for manufacturing the same shown below.

[0010] <Method for Manufacturing a Semiconductor Laser Element> A method for manufacturing a semiconductor laser element according to the present disclosure will be described. The method for manufacturing a semiconductor laser element according to the present disclosure includes a first conductive side semiconductor layer 2, a second conductive side semiconductor layer 3, and an active layer 4 between the first conductive side semiconductor layer 2 and the second conductive side semiconductor layer 3, and prepares a semiconductor laminate 100 having a first window structure 6a. On the second conductive side semiconductor layer 3, a first electrode 20b having a first opening 25a at a position away from the first window structure 6a in a first direction that becomes the direction of the resonator after singulation is formed in a top view. And performing a first appearance inspection using a virtual line based on the first opening 25a.

[0011] Thereby, since the first opening 25a is located away from the window structure, even if the window structure is provided, inspection can be easily performed.

[0012] Each step of the method for manufacturing a semiconductor laser device will be described. The method for manufacturing a semiconductor laser device includes at least a step of preparing a semiconductor laminate 100, a step of forming a first electrode 20b, and a step of performing a first appearance inspection. The step of forming the first electrode 20b may include a step of forming a first mask 13a and a step of removing the first mask 13a after forming the first electrode material 20a. The method for manufacturing a semiconductor laser device may include a step of forming a second electrode 30b after forming the first electrode 20b. The step of forming the second electrode 30b may include a step of forming a second mask 33a and a step of removing the second mask 33a after forming the second electrode material 30a. In this case, the first appearance inspection is performed after the step of forming the second electrode 30b. Also, a second appearance inspection different from the first appearance inspection may be performed.

[0013] (Step of preparing semiconductor laminate 100) First, a semiconductor laminate 100 is prepared. FIG. 1A is a top view of a wafer 1000 including the semiconductor laminate 100. Hereinafter, the description will be made in the region of one chip surrounded by the dotted line in FIG. 1A. FIG. 1B is a schematic top view showing the step of preparing the semiconductor laminate 100 and is an enlarged top view of the region surrounded by the dotted line in FIG. 1A. FIG. 1C is a cross-sectional view taken along the IC-IC line in FIG. 1B. FIG. 1C is a cross-sectional view that does not include the window structure described later. FIG. 1D is a cross-sectional view taken along the ID-ID line in FIG. 1B.

[0014] In this specification, hereinafter, the direction of the cross-sectional indication line along the ID-ID line in FIG. 1B will be referred to as the first direction. Also, the direction of the IC-IC cross-sectional indication line in FIG. 1B will be referred to as the second direction. The first direction is the direction that becomes the resonator after the wafer 1000 is singulated. The second direction is a direction perpendicular to the first direction in a top view.

[0015] As shown in Figure 1C, the semiconductor laminate 100 includes a substrate 1, a first conductive semiconductor layer 2, a second conductive semiconductor layer 3, and an active layer 4 between the first conductive semiconductor layer 2 and the second conductive semiconductor layer 3. In Embodiment 1, the semiconductor laminate 100 further includes an insulating layer 11. As shown in Figures 1B and 1D, the semiconductor laminate 100 has a first window structure 6a. In Figure 1B, the first window structure 6a is formed in the area enclosed by the dashed line.

[0016] The semiconductor laminate 100 may be laminated by, for example, liquid-phase epitaxy (LPE), metal-organic vapor deposition (MOCVD), or molecular beam epitaxy (MBE). The semiconductor laminate 100 is obtained by sequentially laminating a first conductive semiconductor layer 2, an active layer 4, and a second conductive semiconductor layer 3 on a substrate 1. After laminating the second conductive semiconductor layer 3, a first window structure 6a is formed in the semiconductor laminate 100 by diffusing Zn and group III vacancies. Alternatively, after laminating the second conductive semiconductor layer 3, a second window structure 6b may be formed on the opposite side of the first window structure 6a in the first direction by diffusing Zn and group III vacancies.

[0017] The window structure is a structure formed on and near the edge of a wafer 1000 when it is pulverized into semiconductor laser elements. The window structure has a bandgap energy greater than the energy corresponding to the oscillation wavelength of the laser light, allowing the laser light to pass through. This improves COD resistance. The area where the window structure is formed in a top view can be determined by examining the light absorption behavior using microscopic photoluminescence measurements.

[0018] Substrate 1 is a conductive substrate containing a first-type impurity. The first-type impurity may be an n-type impurity. Substrate 1 may be a GaAs substrate, an InP substrate, or an InAs substrate.

[0019] The first conductive semiconductor layer 2, the active layer 4, and the second conductive semiconductor layer 3 may be, for example, an arsenide semiconductor or a phosphide semiconductor. The arsenide semiconductor may be GaAs, AlGaAs, InGaAs, or AlInGaAs. The phosphide semiconductor may be GaP, AlGaP, InGaP, or AlInGaP. Alternatively, they may be mixed crystals of these, such as InGaAsP.

[0020] The first conductive semiconductor layer 2 may be, for example, a semiconductor layer containing n-type impurities. The first conductive semiconductor layer 2 may include a first conductive cladding layer and a first conductive optical guide layer. The second conductive semiconductor layer 3 may be, for example, a semiconductor layer containing p-type impurities. The second conductive semiconductor layer 3 may include a second conductive cladding layer 3a, a second conductive optical guide layer, and a contact layer 3b. Figures 1C and 1D illustrate the second conductive cladding layer 3a and the contact layer 3b.

[0021] The active layer 4 may be, for example, a quantum well layer, and may be a single quantum well or a multiple quantum well. The well layer may be, for example, InGaP, AlGaInP, InGaAsP, AlGaInAsP, or AlInAsP. The semiconductor laminate 100 is capable of emitting red or infrared light. In this specification, red refers to a laser light with a peak wavelength in the range of 600 nm to 700 nm. Infrared refers to a laser light with a peak wavelength greater than 700 nm and less than or equal to 3000 nm.

[0022] In the examples shown in Figures 1B to 1D, the contact layer 3b is formed in multiple stripe shapes in the first direction, and an insulating layer 11 is formed between each stripe in the second direction. In Figures 1B and 1C, the insulating layer 11 has multiple stripe-shaped openings, and the contact layer 3b is exposed through the stripe-shaped openings of the insulating layer 11. In the second direction, the width of the contact layer 3b is greater than the width of the stripe-shaped openings of the insulating layer 11. That is, the insulating layer 11 is also formed on a part of the upper surface of the contact layer 3b. Furthermore, the contact layer 3b without openings is covered and embedded by the insulating layer 11. The region where the contact layer 3b is exposed is the region that becomes a resonator in the semiconductor laser element. In this embodiment, a method for manufacturing a semiconductor laser element equipped with multiple resonators is illustrated, but there may be only one first opening. That is, this embodiment may also be a method for manufacturing a semiconductor laser element equipped with one resonator.

[0023] The insulating layer 11 may be, for example, SiO2, ZrO2, SiN, Al2O3, AlN, or diamond. Two or more of these materials may be laminated together to form the insulating layer 11.

[0024] (Step of forming the first electrode 20b) Next, the process of forming the first electrode 20b will be described. The process of forming the first electrode 20b is to form the first electrode 20b on the second conductive semiconductor layer 3, having a first opening 25a at a position away from the first window structure 6a in a first direction that will be the direction of the resonator after piece formation, when viewed from above. The process of forming the first electrode 20b may include the steps of forming a first mask 13a, forming a first electrode material 20a, and removing the first mask 13a after forming the first electrode material 20a. Furthermore, the process of forming the first electrode 20b may include the steps of forming a third mask 13b and removing the third mask 13b after forming the first electrode material 20a.

[0025] Figure 2A is a schematic top view illustrating the process of forming the first mask 13a. Figure 2B is a cross-sectional view taken along the line IIB-IIB in Figure 2A. As shown in Figures 2A and 2B, the first mask 13a is formed at a position away from the first window structure 6a in the first direction. The third mask 13b is formed at a position away from the second window structure 6b in the first direction. The first mask 13a and the third mask 13b only need to be formed in one location, or they may be formed in two locations as shown in Figures 2A and 2B. If the first mask 13a is formed in two locations, the first mask 13a is formed on the left and right sides of the contact layer 3b. Similarly, if the third mask 13b is formed in two locations, the third mask 13b is formed on the left and right sides of the contact layer 3b. The first mask 13a and the third mask 13b may be, for example, SiO2 or a resist.

[0026] Next, the first electrode 20b is formed. Figure 3A is a schematic top view of the process of forming the first electrode material 20a. Figure 3B is a cross-sectional view taken along the line IIIB-IIIB in Figure 3A. As shown in Figures 3A and 3B, the first electrode material 20a is provided on the contact layer 3b exposed from the stripe-shaped openings of the insulating layer 11, the insulating layer 11, and the first mask 13a. The first electrode material 20a is provided, for example, by sputtering. The first electrode material 20a has at least one selected from the group consisting of Ti, Mo, Au, Pt, Ni, W, Pd, and ITO. In the cross-sectional view shown in Figure 3B, the thickness from the top surface of the insulating layer 11 to the top surface of the first electrode material 20a may be 0.1 μm or more and 5 μm or less, and preferably 0.2 μm or more and 1 μm or less. As a result, when the first opening 25a and the second opening 25b are formed in the first electrode 20b in a process described later, the difference in contrast between the insulating layer 11 exposed from the first electrode 20b and the first electrode 20b becomes easier to observe, improving the accuracy of the first visual inspection.

[0027] Next, the first mask 13a is removed. Figure 4A is a schematic top view of the process of removing the first mask 13a. Figure 4B is a cross-sectional view along the line IVB-IVB in Figure 4A. As shown in Figure 4A, by removing the first mask 13a, the first electrode material 20a on the first mask 13a is removed, and the first electrode 20b is formed. The portion where the first mask 13a was formed was located away from the first window structure 6a in the first direction when viewed from above. Also, the portion where the third mask 13b was formed was located away from the second window structure 6b in the first direction when viewed from above. Therefore, when viewed from above, the first electrode 20b has a first opening 25a formed at a position away from the first window structure 6a in the first direction and a second opening 25b formed at a position away from the second window structure in the first direction. The insulating layer 11 is exposed from the first electrode 20b by the first opening 25a and the second opening 25b. The insulating layer 11 exposed from the first electrode 20b may be fan-shaped, triangular, square, or trapezoidal.

[0028] The first electrode 20b has multiple first openings 25a and multiple second openings 25b. Preferably, the multiple first openings 25a are symmetrical with respect to the center line CL of the semiconductor laminate 100 extending in the first direction when viewed from above. Similarly, preferably, the multiple second openings 25b are symmetrical with respect to the center line CL of the semiconductor laminate 100 extending in the first direction when viewed from above. This allows the first visual inspection process to be carried out with high accuracy. The first visual inspection will be described later. In Figure 4A, the center line CL is represented by a dashed line.

[0029] In a top view, the multiple first openings 25a and second openings 25b have a pattern of recession in a second direction perpendicular to the first direction. This makes it easy to identify the openings, and inspection can be performed based on this pattern. The first openings 25a and second openings 25b have a pattern of recession in a second direction toward the center line CL. Thus, even in a structure that is not surrounded on all four sides from the first electrode 20b, if more than half of the sides are surrounded by a predetermined material, it will be considered to have an "opening" to that material in this specification.

[0030] (Step of forming the second electrode 30b) Next, the process of forming the second electrode 30b will be described. The process of forming the second electrode 30b is to form the second electrode 30b such that the first opening 25a and the second opening 25b are exposed on the first electrode 20b. The process of forming the second electrode 30b may include the steps of forming the second mask 33a, forming the second electrode material 30a, and removing the second mask 33a and the fourth mask 33b after the second electrode material 30a has been formed.

[0031] First, the second mask 33a is formed. Figure 5A is a schematic top view showing the process of forming the second mask 33a and the fourth mask 33b. Figure 5B is a cross-sectional view along the VB-VB line in Figure 5A. The second mask 33a is formed to continuously cover a portion of the first electrode 20b that overlaps with the first window structure 6a in a top view, and the first opening 25a. As shown in Figure 5B, the second mask 33a continuously covers the first opening 25a and a portion of the upper surface of the first electrode 20b. In Figure 5A, the second mask 33a has a C-shape. The second mask 33a may be, for example, SiO2 or a resist.

[0032] Similarly, in the process of forming the second electrode 30b, the second electrode 30b is formed such that the second opening 25b is exposed. As shown in Figure 5A, the fourth mask 33b is formed. The fourth mask 33b is formed to continuously cover a portion of the first electrode 20b that overlaps with the second window structure 6b in a top view, and the second opening 25b. Similar to the example shown in Figure 5B, the fourth mask 33b continuously covers the second opening 25b and a portion of the top surface of the first electrode 20b. In Figure 5A, the fourth mask 33b has a C-shape.

[0033] Next, the second electrode material 30a is formed. Figure 6A is a schematic top view of the process of forming the second electrode material 30a. Figure 6B is a cross-sectional view taken along the VIB-VIB line in Figure 6A. The second electrode material 30a is formed in the region exposed from the second mask 33a and is connected to the first electrode 20b. The second electrode material 30a may be formed, for example, by sputtering or plating. Figures 6A and 6B are preferably formed by plating, particularly by electroplating. This allows the second electrode material 30a to be formed only in the region where the first electrode 20b is exposed from the second mask 33a. The second electrode material 30a can be efficiently formed on the wafer 1000. The second electrode material 30a has at least one selected from the group consisting of Ti, Mo, Au, Pt, Ni, W, Pd, and ITO. In the cross-sectional view shown in Figure 6B, the thickness of the second electrode material 30a may be 0.5 μm or more and 10 μm or less, and preferably 1 μm or more and 5 μm or less. This makes it easier to observe the contrast between the second electrode 30b and the first electrode 20b in the process described later, improving the accuracy of the second visual inspection. Also, in the top view shown in Figure 6A, the surface roughness (Ra) of the second electrode material 30a is greater than that of the first electrode 20b. This makes it easier to observe the contrast between the second electrode 30b and the first electrode 20b in the process described later, improving the accuracy of the second visual inspection. For example, by forming the first electrode 20b by sputtering and the second electrode 30b by plating, it is possible to form the first electrode 20b and the second electrode 30b with different surface roughnesses. Therefore, the contrast between the first electrode 20b and the second electrode 30b is increased.

[0034] Next, the second mask 33a is removed. Figure 7A is a schematic top view of the step of removing the second mask 33a. Figure 7B is a cross-sectional view along the line VIIB-VIIB in Figure 7A. As shown in Figure 7B, by removing the second mask 33a, the second electrode 30b can be formed such that the first opening 25a is exposed above the first electrode 20b.

[0035] Furthermore, after forming the second electrode material 30a, the fourth mask 33b is removed. As shown in Figure 7A, the second electrode 30b can be formed such that the second opening 25b is exposed above the first electrode 20b.

[0036] The second electrode 30b has a first surface 31a that overlaps with the first window structure 6a when viewed from above, a second surface 31b that does not overlap with the first window structure 6a when viewed from above, and a third surface 31c that connects the first surface 31a and the second surface 31b. In Figure 7A, there are two second surfaces 31b and two third surfaces 31c, and the second surface 31b, the third surface 31c, and the first surface 31a are continuously connected.

[0037] The second electrode 30b has a fourth surface 32a that overlaps with the second window structure 6b when viewed from above, a fifth surface 32b that does not overlap with the second window structure 6b when viewed from above, and a sixth surface 32c that connects the fourth surface 32a and the fifth surface 32b. In Figure 7A, there are two fifth surfaces 32b and two sixth surfaces 32c, and the fifth surface 32b, sixth surface 32c, fourth surface 32a, sixth surface 32c, and fifth surface 32b are connected in a continuous sequence.

[0038] The first surface 31a may be symmetrical with respect to the center line CL. In the first direction, the second surface 31b is further away from the first window structure 6a than the first opening 25a. In other words, in the first direction, the distance from the second surface 31b to the first window structure 6a is greater than the distance from the first opening 25a to the first window structure 6a. As a result, the first opening 25a is exposed from the second electrode 30b. Also, in the second direction, the third surface 31c is further away from the first window structure 6a than the first opening 25a. As a result, the first opening 25a is exposed from the second electrode 30b. The exposure of the first opening 25a from the second electrode 30b allows for accurate first visual inspection.

[0039] The fourth surface 32a may be symmetrical with respect to the center line CL. In the first direction, the fifth surface 32b is further away from the second window structure 6b than the second opening 25b. As a result, the second opening 25b is exposed from the second electrode 30b. Also, in the second direction, the sixth surface 32c is further away from the second window structure 6b than the second opening 25b. As a result, the second opening 25b is exposed from the second electrode 30b. The exposure of the second opening 25b from the second electrode 30b allows for accurate first visual inspection.

[0040] The above describes an example of a method for manufacturing the first electrode 20b and the second electrode 30b for a semiconductor laminate 100 on which the first window structure 6a and the second window structure 6b are formed. In this embodiment, a first visual inspection can be performed using a virtual line based on the first opening 25a and the second opening 25b of the first electrode 20b. A second visual inspection can also be performed based on the first surface 31a and the second surface 31b and the fourth surface 32a and the fifth surface 32b of the second electrode 30b.

[0041] (First visual inspection) Next, an example of the first visual inspection will be explained. The wafer 1000 is cleaved after the second electrode 30b is formed, forming a bar in which multiple semiconductor stacks 100 are arranged in a row. The first visual inspection is, for example, an inspection after cleavage. A virtual line is set based on the first opening 25a. The virtual line can be drawn at any position. Based on the virtual line, for example, the distance from the virtual line to the object to be inspected is measured, and if the distance is within a predetermined range, the inspection may be considered successful. The first visual inspection can be used for various inspections, such as dimensions in a first or second direction, the area of ​​the region where the electrodes are formed, or the position of the cleavage plane.

[0042] By performing a first visual inspection using a virtual line based on the first opening 25a, even if discoloration occurs near the end face due to the formation of the first window structure 6a, the inspection can be performed with high accuracy. Since the first opening 25a is located away from the first window structure 6a in the first direction, the virtual line can be set based on the first opening 25a, which is unaffected by discoloration near the end face. This allows for easy inspection. Furthermore, the first visual inspection can be performed by setting a virtual line based on the second opening 25b.

[0043] As explained using Figure 4A, it is preferable that the multiple first apertures 25a are symmetrical with respect to the center line CL of the semiconductor laminate 100 extending in the first direction when viewed from above. This facilitates the calculation of regions based on virtual lines. Therefore, the man-hours required for image inspection can be reduced. The same applies to the multiple second apertures 25b.

[0044] (Second visual inspection) Next, an example of the second visual inspection will be explained. The second visual inspection is performed based on the second surface 31b, either before or after the first visual inspection. In the second visual inspection, the shape and dimensions of the second electrode 30b may be inspected.

[0045] Since the second surface 31b is located in a position that does not overlap with the first window structure 6a, the virtual line can be set without being affected by discoloration near the end face. As a result, compared to directly observing the first surface 31a which overlaps with the window structure in a top view, the virtual line can be set based on a virtual line located at a distance from the window structure. Therefore, even if discoloration caused by the first window structure 6a occurs, the virtual line can be set accurately and the second visual inspection can be performed. The same applies to the virtual line set based on the fifth surface 32b.

[0046] The first surface 31a, the second surface 31b, and the third surface 31c are preferably symmetrical with respect to the center line CL of the semiconductor laminate 100 extending in the first direction when viewed from above. This makes it easier to calculate the area to be inspected after recognizing the second surface 31b. Therefore, the man-hours required for image inspection can be reduced.

[0047] As described above, the first electrode 20b can be formed and the first visual inspection can be performed by the process described so far. Even if a window structure is formed and discoloration occurs near the end face due to the window structure, the first visual inspection can be performed with high accuracy. Similarly, the second electrode 30b can be formed and the second visual inspection can be performed with high accuracy.

[0048] After performing the first and second visual inspections, dielectric multilayer films are formed on the end face on the first window structure 6a side and the end face on the second window structure 6b side, respectively. Then, the bar is separated into individual pieces to extract multiple semiconductor laser elements. The third electrode 40, which is electrically connected to the first conductive semiconductor layer 2, may be formed before cleaving the wafer 1000 and obtaining the bar. The third electrode 40 may be provided, for example, on the lower surface of the substrate 1.

[0049] <Semiconductor laser element> A semiconductor laser element according to an embodiment will be described. The semiconductor laser element comprises a semiconductor laminate having a first conductive semiconductor layer 2, a second conductive semiconductor layer 3, and an active layer 4 between the first conductive semiconductor layer 2 and the second conductive semiconductor layer 3, and having a first window structure 6a provided at a first end including the first end face 7a of the semiconductor laminate from which laser light is emitted; a first electrode 20b disposed on the second conductive semiconductor layer 3 and having a first opening 25a in a top view, in a first direction forming a resonator, at a position away from the first window structure 6a; a second electrode 30b disposed on the first electrode 20b and having a first surface 31a that overlaps with the first window structure 6a in a top view, a second surface 31b that does not overlap with the first window structure 6a, and a third surface 31c that connects the first surface 31a and the second surface 31b, with the first opening 25a exposed so as not to overlap with the third surface 31c.

[0050] By using a first electrode having a first aperture and a second electrode having a second surface, it is possible to provide a semiconductor laser element that is easy to inspect.

[0051] The following sections will explain matters not described in the manufacturing method of the semiconductor laser element. Figure 8 is a schematic cross-sectional view of the semiconductor laser element in the first direction. The cross-section in Figure 8 corresponds to the cross-sectional direction of line XIII-XIII in Figure 7A. In addition to the configuration described in Figures 7A and 7B, Figure 8 includes a third electrode 40, a first dielectric multilayer film 8a, and a second dielectric multilayer film 8b.

[0052] (First window structure 6a, second window structure 6b) The first window structure 6a is provided at the first end of the semiconductor laminate that emits laser light, including the first end face 7a. Furthermore, the semiconductor laser element may have a second window structure 6b. The second window structure 6b is provided at the second end of the semiconductor laminate that emits laser light, including the second end face 7b.

[0053] (3rd electrode 40) The third electrode 40 is provided on the lower surface of the substrate 1. The third electrode 40 has at least one selected from the group consisting of, for example, Ti, Mo, Au, Pt, Ni, W, Pd, and AuGe. The substrate 1 is conductive, and the semiconductor laser element can be driven by applying a current of a predetermined magnitude between the second electrode 30b, the first electrode 20b, and the third electrode 40.

[0054] (First dielectric multilayer film 8a) The first dielectric multilayer film 8a is provided on the first end face 7a on the side of the first window structure 6a. The first dielectric multilayer film 8a may be provided continuously from the bottom surface of the substrate 1 to the first end face 7a and the top surface of the first electrode 20b, or it may be provided only on the first end face 7a. The first dielectric multilayer film 8a is an anti-reflective coating and can efficiently extract laser light. The first dielectric multilayer film 8a is formed by combining at least two types selected from the group consisting of SiO2, Al2O3, and Ta2O5, for example. The reflectivity of the first dielectric multilayer film 8a at the wavelength of laser light may be, for example, 5% or more and 15% or less.

[0055] (Second dielectric multilayer film 8b) The second dielectric multilayer film 8b is provided on the second end face 7b on the side of the second window structure 6b. The second dielectric multilayer film 8b may be provided continuously from the bottom surface of the substrate 1 to the second end face 7b and the top surface of the first electrode 20b, or it may be provided only on the second end face 7b. The second dielectric multilayer film 8b is a highly reflective coating and can efficiently reflect laser light toward the first end face 7a. The second dielectric multilayer film 8b is formed by combining at least two materials selected from the group consisting of SiO2, Al2O3, and Ta2O5, for example. The reflectivity of the second dielectric multilayer film 8b at the wavelength of laser light may be, for example, 90% or more and 100% or less.

[0056] The embodiments of semiconductor laser elements and their manufacturing methods have been described above, but this disclosure is not limited thereto, and modifications and combinations are possible as appropriate, including the technical concept.

[0057] This disclosure includes the following components. (Section 1) A semiconductor laminate having a first window structure is prepared, comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer between the first conductive semiconductor layer and the second conductive semiconductor layer. In a top view, a first electrode having a first opening at a position away from the first window structure in a first direction that becomes the direction of the resonator after piece formation is formed on the second conductive semiconductor layer, The first visual inspection is performed using a virtual line based on the first opening, A method for manufacturing a semiconductor laser element that includes [the specified component]. (Section 2) The first electrode has a plurality of first openings, The plurality of first openings are symmetrical in a top view with respect to the center line of the semiconductor stack extending in the first direction. A method for manufacturing a semiconductor laser element as described in item 1. (Section 3) The invention further comprises forming a second electrode on the first electrode such that the first opening is exposed, The second electrode has a first surface that overlaps with the first window structure when viewed from above, a second surface that does not overlap with the first window structure when viewed from above, and a third surface that connects the first surface and the second surface. Before or after the first visual inspection, a second visual inspection based on the second surface is performed. A method for manufacturing a semiconductor laser element as described in item 1. (Section 4) The invention further comprises forming a second electrode on the first electrode such that the first opening is exposed, The second electrode has a first surface that is symmetrical with respect to the center line and overlaps with the first window structure when viewed from above, a second surface that does not overlap with the first window structure when viewed from above, and a third surface that connects the first surface and the second surface. Before or after the first visual inspection, a second visual inspection based on the second surface is performed. A method for manufacturing a semiconductor laser element as described in item 2. (Section 5) In the first direction, the second surface of the second electrode is further away from the first window structure than the first opening. A method for manufacturing a semiconductor laser element as described in item 3 or item 4. (Section 6) The second electrode is formed by a plating method. A method for manufacturing a semiconductor laser element as described in item 3 or item 4. (Section 7) In the step of preparing the semiconductor stack, the semiconductor stack has a second window structure on the side opposite to the first window structure in the first direction, In the step of forming the first electrode, the first electrode is formed to have a second opening at a position away from the second window structure in the first direction. In the process of forming the second electrode, the second electrode is formed such that the second opening is exposed. It comprises a fourth surface that overlaps with the second window structure when viewed from above, a fifth surface that does not overlap with the first window structure when viewed from above, and a sixth surface that connects the fourth surface and the fifth surface. A method for manufacturing a semiconductor laser element as described in item 3 or item 4. (Section 8) In a top view, the plurality of first openings have a pattern of being recessed in a second direction perpendicular to the first direction. A method for manufacturing a semiconductor laser element as described in any one of items 1 to 7. (Section 9) The semiconductor stack is capable of emitting red or infrared light. A method for manufacturing a semiconductor laser element according to any one of items 1 to 8. (Section 10) A semiconductor laminate comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer between the first conductive semiconductor layer and the second conductive semiconductor layer, and having a first window structure provided at a first end including a first end face from which laser light is emitted, A first electrode is disposed on the second conductive semiconductor layer and, when viewed from above, has a first opening at a position away from the first window structure in the first direction forming a resonator, A second electrode is positioned on the first electrode and, in a top view, has a first surface that overlaps with the first window structure, a second surface that does not overlap with the first window structure, and a third surface that connects the first surface and the second surface, with the first opening exposed so as not to overlap with the third surface. A semiconductor laser element equipped with the following features. (Section 11) The semiconductor stack emits red or infrared laser light. The semiconductor laser element according to claim 10. [Explanation of Symbols]

[0058] 1 circuit board 2. First conductive semiconductor layer 3. Second conductive semiconductor layer 3a Second conductive cladding layer 3b Contact layer 4 Active layer 6a First window structure 6b Second window structure 7a First end surface 7b Second end face 8a First dielectric multilayer film 8b Second dielectric multilayer film 11 Insulating layer 13a First Mask 13b Third Mask 20a 1st electrode material 20b 1st electrode 25a 1st opening 25b 2nd opening 30a 2nd electrode material 30b 2nd electrode 31a 1st page 31b 2nd side 31c 3rd page 32a 4th page 32b Page 5 32c page 6 33a Second Mask 33b Fourth Mask 40 3rd electrode 100 Semiconductor Stack 1000 wafers

Claims

1. A semiconductor laminate having a first window structure is prepared, comprising a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer between the first conductive semiconductor layer and the second conductive semiconductor layer. In a top view, a first electrode having a first opening at a position away from the first window structure in a first direction that becomes the direction of the resonator after individualization is formed on the second conductive semiconductor layer, The first visual inspection is performed using a virtual line based on the first opening, A method for manufacturing a semiconductor laser element that includes [the specified component].

2. The first electrode has a plurality of first openings, The plurality of first openings are symmetrical in a top view with respect to the center line of the semiconductor stack extending in the first direction. A method for manufacturing a semiconductor laser element according to claim 1.

3. The invention further comprises forming a second electrode on the first electrode such that the first opening is exposed, The second electrode has a first surface that overlaps with the first window structure when viewed from above, a second surface that does not overlap with the first window structure when viewed from above, and a third surface that connects the first surface and the second surface. Before performing the first visual inspection, or after performing the first visual inspection, perform the second visual inspection based on the second surface. A method for manufacturing a semiconductor laser element according to claim 1.

4. The invention further comprises forming a second electrode on the first electrode such that the first opening is exposed, The second electrode has a first surface that is symmetrical with respect to the center line and overlaps with the first window structure when viewed from above, a second surface that does not overlap with the first window structure when viewed from above, and a third surface that connects the first surface and the second surface. Before performing the first visual inspection, or after performing the first visual inspection, perform the second visual inspection based on the second surface. A method for manufacturing a semiconductor laser element according to claim 2.

5. In the first direction, the second surface of the second electrode is further away from the first window structure than the first opening. A method for manufacturing a semiconductor laser element according to claim 3 or 4.

6. The second electrode is formed by a plating method. A method for manufacturing a semiconductor laser element according to claim 3 or 4.

7. In the step of preparing the semiconductor stack, the semiconductor stack has a second window structure on the side opposite to the first window structure in the first direction, In the step of forming the first electrode, the first electrode is formed to have a second opening at a position away from the second window structure in the first direction. In the process of forming the second electrode, the second electrode is formed such that the second opening is exposed. It comprises a fourth surface that overlaps with the second window structure when viewed from above, a fifth surface that does not overlap with the first window structure when viewed from above, and a sixth surface that connects the fourth surface and the fifth surface. A method for manufacturing a semiconductor laser element according to claim 3 or 4.

8. In a top view, the plurality of first openings have a pattern of being recessed in a second direction perpendicular to the first direction. A method for manufacturing a semiconductor laser element according to any one of claims 1 to 4.

9. The semiconductor stack is capable of emitting red or infrared light. A method for manufacturing a semiconductor laser element according to any one of claims 1 to 4.

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