JP5636877B2 - Semiconductor laser device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a semiconductor laser device including a semiconductor laser element, a mirror, and a lens, and a manufacturing method thereof.

  As a conventional semiconductor laser device, there is an optical conversion device in which an optical signal sent from a laser emission source is reflected by a semi-transparent mirror of a prism, and the optical signal is guided to an optical fiber by a lens integrally attached to a package. (For example, Patent Document 1).

Japanese Unexamined Patent Publication No. 8-166527

In a conventional semiconductor laser device, when laser light emitted from a semiconductor laser element and reflected by a mirror is passed through a lens, it is necessary to adjust and mount the inclination of the lens in addition to the position where the lens is disposed. When the adjustment of the position and tilt is not accurate, the laser beam taken out through the lens is displaced and the beam is tilted. In addition, the adjustment of such a lens requires a plurality of steps of aligning the center of the lens on the optical axis of the laser beam, adjusting the distance of the lens, and adjusting the tilt of the lens. Is complicated and requires adjustment time.
Accordingly, it is an object of the present application to provide a semiconductor laser device that can extract desired laser light without positional deviation and beam tilt, and a method for manufacturing a semiconductor laser device that can efficiently mount a lens.

The semiconductor laser device according to the embodiment includes a substrate, a semiconductor laser element provided on the substrate, a mirror that reflects laser light emitted from the semiconductor laser element in a direction different from the emission direction, and the mirror. And a lens that controls the laser beam, the mirror is provided on the substrate, and the lens is provided on the mirror.
Further, the method of manufacturing a semiconductor laser device according to the embodiment includes a step of mounting a semiconductor laser element and a mirror that reflects laser light emitted from the semiconductor laser element in a direction different from the emission direction on a substrate, And mounting a lens for controlling the laser light reflected by the mirror by aligning the lens in the direction perpendicular to the optical axis while fixing the position in the optical axis direction.

  According to the semiconductor laser device of the present application, it is possible to take out laser light with no positional deviation or beam tilt. Moreover, according to the manufacturing method of the semiconductor laser device of the present application, the lens can be mounted efficiently.

It is a schematic perspective view for demonstrating the structure of the semiconductor laser apparatus of embodiment. It is a schematic sectional drawing for demonstrating the structure of the semiconductor laser apparatus of embodiment. It is a schematic perspective view for demonstrating the structure of the semiconductor laser apparatus of embodiment. It is a schematic perspective view for demonstrating the structure of the semiconductor laser apparatus of embodiment.

  Embodiments will be described below with reference to the drawings. However, the form shown below exemplifies the semiconductor laser device and the manufacturing method thereof for embodying the technical idea of the present invention, and does not limit the present invention to the following. In addition, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation.

(Embodiment 1)
FIG. 1 is a perspective view of the semiconductor laser device according to the embodiment, and FIG. 2 is a cross-sectional view taken along a line AA in FIG. 1, as viewed from the Y-axis direction.

  In the semiconductor laser device 1 of the embodiment, the semiconductor laser element 3 is disposed on the substrate 2, and the mirror 4 that reflects the laser light L emitted from the semiconductor laser element 3 in the direction different from the emission direction is disposed on the same substrate 2. Has been. A lens for controlling the laser beam reflected by the mirror is provided on the mirror 4. In FIG. 1, a lens including a lens 5a and a mounting portion 5b is shown. For convenience of explanation, FIG. 1 shows the lens portion 5a and the attachment portion 5b through the lens portion 5a. The laser light L is emitted in parallel with the substrate, the X direction is the laser light emission direction, the Y direction is perpendicular to the X direction and parallel to the substrate, the Z direction is the X direction, and the direction perpendicular to the substrate. To do.

According to such a semiconductor laser device, it is possible to take out a laser beam with no positional deviation or beam tilt, and it is possible to mount a lens efficiently. Details will be described below.
In order to emit the laser light emitted from the semiconductor laser element to the outside so as not to shift the position of the optical axis, the lens in the horizontal direction (X direction and Y direction) so that the optical axis passes through the center of the lens. The position needs to be determined. Even if the optical axis passes through the center of the lens, if the lens itself is mounted at a predetermined position where it should be placed, the beam will bend, so the lens is perpendicular to the optical axis. Need to be arranged as follows.
In a semiconductor laser device having a mirror and a lens, the size of the device can be reduced as compared with a case where a mirror and a lens are separately provided, but an allowable tolerance range is very small, and a margin for a mounting tolerance of the device is small. turn into. Therefore, it is very difficult to mount with high accuracy without taking time.
Therefore, in the semiconductor laser device of the embodiment, since the lens is provided on the mirror, the lens and the mirror come into contact with each other directly or through a separate member at the time of mounting, so the position in the vertical direction (Z direction) is determined. The lens is held on a plane parallel to the XY plane or a plane having a certain angle with respect to the XY plane. Then, it is not necessary to rotate the X and Y axes as rotation axes, that is, to incline the lens for adjustment. In this way, since it is not necessary to consider the tilt of the lens, only the positions in the horizontal X and Y directions need be adjusted. As a result, it is possible to mount the lens more easily than before. Alternatively, the time required to adjust the tilt of the lens can be spent on the alignment of the center of the lens so that the accuracy of optical axis alignment can be improved, and laser light without misalignment or beam tilt can be achieved. Can be taken out.
That is, in the semiconductor laser device of the embodiment, since the lens is provided on the mirror, the lens is held on a plane parallel to the XY plane or a plane having a certain angle with respect to the XY plane. Since the position in the axial direction is determined in advance, it is not necessary to adjust the inclination. Therefore, it is only necessary to perform alignment on the plane in the X axis and the Y axis, the load for adjusting the mounting position of the lens can be remarkably reduced, and the lens can be mounted efficiently.

Hereinafter, each configuration of the embodiment will be described.
(Semiconductor laser element 3)
In the semiconductor laser element 3, when a voltage is applied and a current exceeding a threshold value flows, laser oscillation occurs in the active layer and its vicinity, and the generated laser light is emitted to the outside through the waveguide region. It is. Further, the semiconductor material is a compound using a compound such as III-V group or II-VI group, and may emit laser light of any wavelength. As a structure of the semiconductor laser element, for example, an n-type semiconductor layer, an active layer, and a p-type semiconductor layer are sequentially stacked on a conductive or insulating substrate, and an insulating film or an electrode is formed on the surface of the semiconductor layer. Is mentioned. Further, the semiconductor laser device may have one or a plurality of semiconductor laser elements.

(Substrate 2)
In the semiconductor laser device of this embodiment, a semiconductor laser element and a mirror are placed on a substrate. The substrate is also used to efficiently release the heat generated in the semiconductor laser element to the outside.
The substrate is preferably formed of a material having a relatively high thermal conductivity, for example, a material of about 20 W / mK or more. Specific materials include metals such as Cu, Al, Fe, Ni, Mo, CuW, and CuMo, and ceramics such as AlN, SiC, and alumina. These metals or ceramics may be used as a base material, and the entire surface or a part thereof may be plated with Au, Ag, Al, or the like. Especially, what is formed with the copper or copper alloy by which the surface was gold-plated is preferable.

The shape and size of the substrate are not particularly limited, and can be appropriately adjusted according to the final desired shape and size of the semiconductor laser device. As the planar shape, a polygonal shape including a rectangle, a circle, an ellipse, or a shape similar to these can be used. For example, a flat plate having a rectangular shape of about 5 to 50 mm square can be used. The thickness is preferably about 0.5 to 5 mm. Moreover, a board | substrate is not limited to a flat form, The recessed part and / or convex part may be provided in the surface. Specifically, a semiconductor laser element and / or a region where a mirror is placed is provided with a concave portion or a convex portion.
Although not shown, the substrate may be provided with a terminal for connecting to an external power source. Examples of the terminal include an airtight terminal formed of glass and provided so as to penetrate the substrate, and a terminal formed of ceramic and provided on the surface of the substrate. Further, a wiring pattern may be provided on the substrate surface or inside the substrate.

(Mirror 4)
The mirror 4 reflects the laser light from the semiconductor laser element in a desired direction, or changes the direction by adjusting the optical axis of the laser light from the semiconductor laser element. Moreover, you may provide the function to perform intensity modulation or wavelength conversion.
The mirror has a reflection surface disposed at a position facing the emission surface of the semiconductor laser element. For example, it has a reflection surface inclined by 45 ° with respect to the emission surface of the semiconductor laser element, the laser beam is reflected by the reflection surface, and the optical axis of the laser beam emitted from the semiconductor laser element is changed by 90 ° Is mentioned.
As shown in FIG. 2, the outer shape of the mirror has an upper surface 4a and a bottom surface 4b with the reflecting surface 4c interposed therebetween, and the upper surface 4a, the bottom surface 4b, and the reflecting surface 4c each have a certain angle. . The bottom surface 4b is preferably bonded to the substrate, and a lens described later is preferably bonded to the top surface 4a opposite to the bottom surface. With such a structure, it is possible to reflect the laser beam emitted from the semiconductor laser element in a direction parallel to the substrate surface and to extract light in a certain upper direction. Moreover, it is preferable to have the bottom face 4b bonded to the substrate and the top face 4a substantially parallel to the bottom face 4b. Since the bottom surface and the top surface are substantially parallel, the lens can be disposed substantially parallel to the substrate and the semiconductor laser element. Therefore, alignment can be performed simply by arranging the lens on the mirror, and the semiconductor laser device can be easily assembled.
The mirror may be any material that can reflect laser light, and can be formed of glass, quartz, synthetic quartz, sapphire, ceramic, plastic, metal, dielectric material, or the like. Further, in order to adhere to the substrate or the lens, thin films such as Ti / Pt / Au, Ti / Ni / Au, Ni / Au, Ti / Ni / Ag may be formed on the bottom and back surfaces of the mirror.

(Lens 5)
The lens 5 plays a role of controlling the laser light. “Controlling the laser beam” means that the laser beam is collimated, condensed or diffused. The lens 5 is disposed in the emission direction of the laser light reflected by the mirror. In the semiconductor laser device of the embodiment, as shown in FIG. 2, the lens 5 is disposed and bonded on the upper surface 4a facing the bottom surface 4b bonded to the mirror substrate.

  The lens portion 5a is made of a material that can transmit laser light, and can be formed of a commonly used material such as glass, quartz, synthetic quartz, sapphire, transparent ceramic, plastic, or the like. For application to various applications, it is preferable that the light extracted from the semiconductor laser device is parallel light. Therefore, in order to emit the laser light as parallel light from the semiconductor laser device, it is preferable to use a collimating lens. In addition, the shape of the lens part 5a is not specifically limited, It is preferable that it is circular or elliptical. The size of the lens unit 5a can be arbitrarily determined according to the laser beam that is finally desired to be extracted from the semiconductor laser device.

The lens 5 includes a lens portion 5a and a mounting portion 5b that are integrally molded. The mounting portion 5b is preferably molded from the same material as the lens portion 5a in order to fix the mirror and the lens at a fixed angle. As the shape, the attachment portion 5b is preferably molded into a flat plate shape because it is bonded to a mirror or another member. Moreover, the lens part 5a and the attachment part 5b holding the lens part 5a may be formed of different materials. The attachment portion is a member for connecting and fixing the lens and the mirror. The material for forming the attachment portion is not particularly limited, and various materials such as metals, alloys, and ceramics can be used. When connecting and fixing with a mirror by welding or the like, the attachment portion is preferably formed of a material suitable for this, for example, stainless steel. In order to adhere by the same method as the semiconductor laser, a thin film such as Ti / Pt / Au, Ti / Ni / Au, Ni / Au, Ti / Ni / Ag may be formed on the bottom surface of the attachment portion. The attachment portion is suitably a plate having an opening at the position of the lens portion.
In any case, the planar shape of the lens is not particularly limited, and examples thereof include a rectangular shape. Moreover, the thickness of a lens and an attaching part is not specifically limited.

Hereinafter, other configurations will be described.
The semiconductor laser element 3 may be disposed on the substrate via the submount 6. For the submount, a member having high thermal conductivity is preferably used for heat dissipation, and specific examples include AlN, CuW, diamond, SiC, ceramics, and the like. A thin film such as Ti / Pt / Au or Ni / Au may be formed on the surface. The mirror 4 may also be disposed on the substrate via a similar submount. In that case, the semiconductor laser element and the mirror may be arranged on the same submount or may be arranged on different submounts. By disposing on the different submounts, it is easy to finely adjust each member when the semiconductor laser element and the mirror are disposed on the substrate, and the assembling accuracy can be improved.
Further, another member may be provided between the mirror and the lens. That is, the mirror and the lens may be provided directly or via separate members. Even when another member is provided in between, the member and the lens may be bonded by a method described later, as in the case where the mirror and the lens are in direct contact, but from the viewpoint of improving mounting accuracy, It is preferable that the mirror and the lens are directly bonded.

  In the semiconductor laser device 1 of the present application, the cap 7 may be attached to the substrate 2 and sealed so as to cover the semiconductor laser element 3. When a semiconductor laser element using a semiconductor material with a short wavelength of about 320 to 530 nm (for example, a nitride semiconductor) is used, it is easy to collect organic matter and moisture. This is preferable because it can improve the airtightness and improve the waterproofness and dustproofness.

Specifically, as shown in FIG. 4, the cap bonded to the substrate can have an opening at the top, and a transparent member can be supported on the opening. The laser beam can be extracted from the sexual member.
Examples of the shape of the cap include a bottomed cylindrical shape (such as a cylinder or a polygonal column), a truncated cone shape (such as a truncated cone or a polygonal truncated cone), a dome shape, and a deformed shape thereof. The cap is preferably formed of a material having high thermal conductivity. For example, a material such as Ni, Co, Fe, Ni—Fe alloy, Kovar, or brass can be used.
A portion corresponding to the laser light emission part on the upper surface or side surface of the cap has an opening through which the laser light passes. The opening is preferably formed on the upper surface of the cap. The translucent member can be formed of, for example, glass, sapphire, ceramics, resin, or the like. Further, a light transmissive film may be provided on the surface so that the laser light can be suitably transmitted. Moreover, the translucent member may contain the wavelength conversion member, the light-diffusion material, etc.

  A photodiode may be disposed on the substrate in order to monitor the output of the semiconductor laser element. In addition, a protective element may be arranged to protect the semiconductor laser element from element destruction and performance deterioration due to excessive voltage application.

In addition, the semiconductor laser device of the embodiment can be manufactured as follows.
First, a semiconductor laser element and a mirror that reflects laser light emitted from the semiconductor laser element in a direction different from the emission direction are mounted on the substrate.
The semiconductor laser element can be mounted by bonding the semiconductor laser element and the substrate after holding the bonding surfaces, and holding the semiconductor laser element under a predetermined temperature and pressure. Etc. As a bonding material for the semiconductor laser element and the substrate, a high melting point material of 250 ° C. or higher, an Au-based low melting point solder material (for example, Au / Sn, Ni / Au, Ni / Pd / Au, etc.), an Ag-based bonding material, a bonding resin Can be used.

  The semiconductor laser element may have any structure such as face-down mounting in which the semiconductor layer side of the semiconductor laser element is mounted on the substrate side, and face-up mounting in which the substrate side of the semiconductor laser element is mounted on the substrate side.

  When a submount is used, the semiconductor laser element is mounted on the submount and bonded, and then the submount is bonded to the substrate. The submount is mounted on the substrate and bonded, and then the semiconductor laser element is mounted. And a method of adhering to the submount. The mounting of the semiconductor laser element on the submount and the mounting of the submount on the substrate can be performed in the same manner as the mounting of the semiconductor laser element on the substrate.

  Thereafter, it is preferable to mount a mirror. By mounting the semiconductor laser element first and then mounting the mirror, the position of the mirror can be adjusted so that the laser light L is reflected in an appropriate direction, and the mirror can be mounted. The mirror can also be mounted in the same manner as the semiconductor laser element. The mirror can be bonded by adjusting the position of the mirror and aligning the bonding surface between the mirror and the substrate and then holding the mirror and the substrate under a predetermined temperature and pressure. Further, in the bonding between the mirror and the substrate, the bonding can also be performed with a UV curable adhesive, a thermosetting adhesive or the like.

Further, the mirror may be mounted first and then the semiconductor laser may be mounted. When mounting in this order, mounting the semiconductor laser element after mounting the mirror allows the position of the mirror to be recognized by a camera, etc., and determining the mounting position of the semiconductor laser element based on the mirror position The semiconductor laser element and the mirror can be mounted at an accurate position by a simple method.
After mounting the semiconductor laser element and the mirror, each member is electrically connected by die bonding or wire bonding.

  Subsequently, the lens 5 is aligned and bonded. Positioning in the X and Y directions is performed with the lens mounting portion 5b in contact with the mirror and the position in the Z direction fixed. At this time, an adjustment is made while applying a current to the semiconductor laser element and confirming the optical axis direction of the laser beam. Then, adjustment is performed by moving the lens 5 in the X direction and the Y direction so that the optical axis of the laser beam passes through an appropriate position of the lens unit 5a. Since the attachment portion is in contact with the mirror, the lens can be moved only on the XY plane or on a plane having a certain angle with respect to the XY plane. It is not necessary to consider the tilt of the lens, and it can be mounted with high accuracy and efficiency. In this manner, the mounting position of the lens is determined, and the mounting portion is fixed to the mirror using a UV curable adhesive such as an epoxy resin or an acrylic resin, a thermosetting adhesive, or the like. As a method for fixing the mirror and the attachment portion, after joining the joining surfaces of the mirror and the attachment portion, UV light is irradiated in the case of a UV curable adhesive. Moreover, in a thermosetting adhesive, it can adhere | attach by hold | maintaining under predetermined temperature and pressure. Bonding can also be performed by a method similar to laser welding or the like or mounting of a semiconductor laser element. As described above, even when a separate member is interposed between the mirror and the lens, it is possible to bond them in the same manner.

  When the semiconductor laser device is sealed with a cap, it can be bonded to the substrate by resistance welding or soldering. When sealing, it is preferable to seal in dry air or nitrogen atmosphere having a dew point of −10 ° C. or lower. In addition, each member may be pretreated using a method such as ashing or heat treatment to remove moisture and organic substances attached to each member.

(Embodiment 2)
The present embodiment will be described based on FIG. In addition, about the member similar to Embodiment 1, the same number is used and the overlapping description is abbreviate | omitted.
In this embodiment, the semiconductor laser device has a plurality of semiconductor laser elements. In this case, semiconductor laser elements having the same wavelength band may be used, or semiconductor lasers having different wavelength bands may be used. By using a plurality of semiconductor laser elements of the same wavelength band, a high-power laser device can be obtained.
The plurality of semiconductor laser elements are mounted at a predetermined interval on a single submount. A lens corresponding to the beam of each semiconductor laser element includes a plurality of lenses for transmitting each beam through a single mounting portion.
In the semiconductor laser device of the embodiment, a multi-emitter type semiconductor laser device using a plurality of semiconductor laser elements can be obtained, and a high-power semiconductor laser device can be obtained.
In addition, since the laser light is usually diffused light, in a multi-emitter type semiconductor laser device, adjacent beams may interfere with each other to affect the obtained beam shape and output. However, in the present embodiment, since the mirror and the lens are provided close to each other, it is possible to prevent the adjacent beams from interfering with each other with a short distance from when the laser light is emitted until reaching the lens. That is, even in a multi-emitter type semiconductor laser device, interference of laser light can be suppressed and influence on output and beam shape can be reduced.
As a manufacturing method of the semiconductor laser device of the present embodiment, in addition to the manufacturing method of the first embodiment, the arrangement direction of the plurality of semiconductor laser elements and each member are arranged in parallel.
First, in the semiconductor laser element, the semiconductor laser elements are arranged so that the beams of the respective semiconductor laser elements are emitted substantially in parallel. For example, an image of a substrate or a submount can be recognized by a camera or the like, and a semiconductor laser element can be mounted at a predetermined position on the basis of a pattern or the like provided on the surface thereof.
The mirror is arranged so that the arrangement direction of the semiconductor laser elements (Y direction in FIG. 3) and the reflecting surface of the mirror are substantially parallel. As a method for positioning the mirror, the position can be determined by image recognition as in the case of the semiconductor laser element.
The lenses are arranged so that the arrangement direction of the plurality of semiconductor laser elements and the arrangement direction of the plurality of lens portions are substantially parallel. As a positioning method, adjustment may be performed by image recognition as described above, or the position may be adjusted while driving the semiconductor laser element and confirming the optical axis direction of the laser beam. Thereafter, as in the first embodiment, the semiconductor laser device of the second embodiment can be obtained by aligning and bonding the lenses.

  The nitride semiconductor laser device of the present invention can be used for all devices such as an optical disk, an optical communication system, a projector, a display, a printer, or a measuring instrument.

1: Semiconductor laser device 2: Substrate 3: Semiconductor laser element 4: Mirror 4a: Upper surface 4b: Bottom surface 4c: Reflecting surface 5: Lens 5a: Lens portion 5b: Mounting portion 6: Submount 7: Cap

Claims (8)

A substrate, a semiconductor laser element provided on the substrate, a mirror for reflecting in a direction different from the emitted and the emission direction laser beam from the semiconductor laser element, a lens for controlling the laser beam reflected by the mirror In a semiconductor laser device comprising a plurality of submounts provided on the substrate ,
The semiconductor laser element and the mirror are provided on different submounts,
The lens is a semiconductor laser device provided on the mirror.   The mirror has a bottom surface bonded to the substrate and a top surface substantially parallel to the bottom surface, the lens has a plane perpendicular to the optical axis of the lens, and the plane of the lens is bonded to the top surface of the mirror. The semiconductor laser device according to claim 1.   The semiconductor laser device according to claim 1, wherein a plurality of the semiconductor laser elements are provided on the substrate.   The semiconductor laser device according to claim 1, wherein a cap that covers the semiconductor laser element, the mirror, and the lens is bonded to the substrate. On a plurality of sub-mount provided on a substrate, a step of mounting a mirror for reflecting the laser beam emitted from the semiconductor laser element and the semiconductor laser element in a direction different from the emission direction, on different submounts ,
A method of manufacturing a semiconductor laser device, comprising: mounting a lens for controlling the laser light reflected by the mirror in a state in which the position in the optical axis direction is fixed and in a direction perpendicular to the optical axis.   6. The method of manufacturing a semiconductor laser device according to claim 5, wherein the lens is fixed in position in the optical axis direction by being brought into contact with the mirror. The lens consists of a lens part and a mounting part,
  5. The semiconductor laser device according to claim 1, wherein the mirror and the attachment portion are welded. 6. In the step of mounting the semiconductor laser element and the mirror,
  The method of manufacturing a semiconductor laser device according to claim 5, wherein the semiconductor laser element is mounted first, and then the mirror is mounted.

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