JP2016040822A - Surface emitting laser device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface emitting laser device and the like in which a microlens is positioned with respect to a surface emitting laser with high accuracy by a simple method.SOLUTION: A present surface emitting laser device comprises: a surface emitting laser substrate in which a surface emitting laser and a plurality of first adhesive fixing regions are formed on one surface of a semiconductor substrate; a microlens substrate including a microlens on which outgoing beams of the surface emitting laser are incident, a plurality of bridge columns which project on the one surface side of the semiconductor substrate and second adhesive fixing regions each formed at a position opposite to each first adhesive fixing region on a bottom face of each bridge column; and an adhesive for adhering the first adhesive fixing regions and the second adhesive fixing regions. The surface emitting laser substrate and the microlens substrate are fixed in a state of being self-aligned by a resilience generated at the time of melting of the adhesive.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a surface emitting laser device and a manufacturing method thereof.

  In recent years, research on high-power lasers such as various optical devices, laser projectors, and light source lasers for laser processing machines has been actively conducted. In such a high-power laser, for example, the light from the surface emitting laser array is condensed to achieve high output. A surface-emitting laser is suitable as a light source for a high-power laser because it emits light in a direction perpendicular to the substrate, is easily integrated, and is easily inspected. As a configuration of a high-power laser, for example, a configuration in which a collimator lens made of a microlens array is arranged in the light emitting direction of a surface emitting laser array that is a light source, and a condensing lens is further arranged.

  The surface emitting laser array has a configuration in which, for example, surface emitting lasers having a mesa structure of several tens of μm square as unit elements are arranged in a square or hexagonal close-packed lattice shape. On the other hand, the microlens array for using the emitted light from the surface emitting laser array as collimator light is made of synthetic quartz or the like and is formed corresponding to the unit element of the surface emitting laser array.

  In such a surface emitting laser array and a microlens array configuration, in order to increase the light use efficiency of the surface emitting laser, the mounting accuracy of the microlens to the surface emitting laser is high in a few ± m in three directions of XYZ. Is needed. Therefore, various studies have been made to improve the mounting accuracy of the microlens for the surface emitting laser. A specific example of the conventional technique for aligning the microlens with high accuracy with respect to the surface emitting laser will be described below.

  A photonic device can be given as a first example of the prior art for aligning a microlens with high accuracy with respect to a surface emitting laser. This photonic device is an apparatus in which a surface emitting laser and a microlens are integrated, and a plurality of legs for maintaining a predetermined distance from the surface emitting laser are provided on a substrate on which the surface emitting laser is formed. The microlens structure is arranged.

  In this photonic device, high-precision mounting in the Z direction is possible by fixing a leg portion integrated and extended to the microlens structure to the surface of the substrate on which the surface emitting laser is formed. For alignment in the X and Y directions, a position adjustment method while observing the image of the surface emitting laser and the lens, and a position adjustment method while receiving the light transmitted through the lens by emitting the surface emitting laser array. Types are disclosed (for example, see Patent Document 1).

  As a second example of the prior art for aligning a microlens with respect to a surface emitting laser with high accuracy, an optical element mounting device can be cited. In this optical element mounting apparatus, in order to enable highly accurate alignment in the XY and Z directions, the protrusion of the alignment reference portion is integrally formed on one surface of the microlens array substrate. Then, a recess of the alignment reference part is formed on the surface of one surface emitting laser array substrate, and the both alignment reference parts are fitted together, thereby enabling high-precision mounting.

  In this optical element mounting device, the projection on the microlens side is formed integrally with the microlens during the molding of the microlens resin, and the depression of the surface emitting laser array side substrate is highly accurate by etching using photolithography technology of the semiconductor process. To make. Thereby, the mounting accuracy after assembly is ensured (for example, refer to Patent Document 2).

As a third example of the prior art for mounting a microlens with high accuracy on a surface emitting laser, a surface emitting light source can be cited. In this surface-emitting light source, a microlens is formed on a surface-emitting laser array substrate corresponding to each surface-emitting laser that is a unit element. The microlens is manufactured by aligning the surface emitting laser and the microlens with high precision by molding a dielectric such as SiO ₂ formed on the surface of the surface emitting laser into the microlens by photolithography technology. (For example, refer to Patent Document 3).

  However, in the first example of the prior art, a complicated and expensive mounting apparatus is required to perform the above-described two types of position adjustment methods, and the mounting tact time is slow. That is, it is difficult to align the microlens with respect to the surface emitting laser with high accuracy by a simple method.

  In the second example of the prior art, since the height of the protrusion and the depth of the recess are at most the thickness of the substrate, the height of the protrusion and the depth of the recess are both several hundred μm or less. That is, the height of the protrusion is extremely low, and the depth of the recess is extremely shallow. Therefore, it is necessary to fix the microlens on the surface emitting laser with an adhesive, a brazing material, or the like, and there is a problem that the lens is displaced in the process. That is, with this method, it is difficult to align the microlens with respect to the surface emitting laser with high accuracy.

  In the third example of the prior art, since the microlens is formed directly on the surface emitting laser array substrate with a dielectric or the like, the reliability of the surface emitting laser deteriorates due to the stress from the dielectric of the microlens substrate. There were many technical issues to implement. That is, it is difficult to put the microlens to the surface emitting laser with this method with high accuracy.

  The present invention has been made in view of the above, and an object of the present invention is to provide a surface-emitting laser device or the like in which microlenses are aligned with high accuracy with respect to a surface-emitting laser by a simple method.

  The surface-emitting laser device includes a surface-emitting laser substrate in which a surface-emitting laser and a plurality of first adhesive fixing regions are formed on one surface of a semiconductor substrate, a microlens on which light emitted from the surface-emitting laser is incident, and the semiconductor A microlens substrate comprising: a plurality of bridge piers protruding on one surface side of the substrate; and a second adhesive fixing region formed at a position facing the first adhesive fixing region on the bottom surface of each of the bridge piers; An adhesive that bonds the first adhesive fixing region and the second adhesive fixing region, and the surface emitting laser substrate and the microlens substrate are caused by a restoring force generated when the adhesive is melted. It is required to be fixed in a self-aligned state.

  According to the disclosed technology, it is possible to provide a surface emitting laser device in which microlenses are aligned with high accuracy with respect to a surface emitting laser by a simple method.

It is sectional drawing which illustrates the main part of the surface emitting laser apparatus which concerns on 1st Embodiment. It is a figure which illustrates the surface emitting laser array substrate which concerns on 1st Embodiment. It is a figure which illustrates the microlens array board | substrate which concerns on 1st Embodiment. FIG. 6 is a diagram (part 1) illustrating a manufacturing process of the surface-emitting laser device according to the first embodiment; FIG. 6 is a second diagram illustrating a manufacturing process of the surface-emitting laser device according to the first embodiment; FIG. 6 is a diagram (No. 3) for exemplifying the manufacturing process for the surface emitting laser device according to the first embodiment; FIG. 6 is a diagram (No. 4) for exemplifying the manufacturing process for the surface-emitting laser device according to the first embodiment; It is a figure explaining the principle in which self alignment is performed. It is a top view which illustrates the surface emitting laser array substrate which concerns on 2nd Embodiment. It is a top view which illustrates the surface emitting laser array substrate which concerns on 3rd Embodiment. It is a figure which illustrates the micro lens array board | substrate which concerns on 4th Embodiment. It is sectional drawing which illustrates the main part of the surface emitting laser apparatus which concerns on 5th Embodiment. It is a top view which illustrates the adhesion fixation area | region of the surface emitting laser apparatus which concerns on 5th Embodiment. It is a figure which illustrates the manufacturing process of the surface emitting laser apparatus which concerns on 5th Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

<First Embodiment>
[Structure of surface emitting laser device]
FIG. 1 is a cross-sectional view illustrating the main part of the surface-emitting laser device according to the first embodiment. As shown in FIG. 1, the surface emitting laser device 1 generally includes a surface emitting laser array substrate 10, a microlens array substrate 20, and an adhesive 30. The microlens array substrate 20 is mounted on the surface emitting laser array substrate 10 via an adhesive 30. The surface emitting laser array substrate 10 can be mounted on the surface of a heat sink (not shown), for example.

  In this embodiment, for the sake of convenience, the microlens array substrate 20 side is defined as the upper side or one side, and the surface emitting laser array substrate 10 side is defined as the lower side or the other side. Also, the surface on the microlens array substrate 20 side of each part is defined as one surface or upper surface, and the surface on the surface emitting laser array substrate 10 side is defined as the other surface or lower surface. However, the surface emitting laser device 1 can be used upside down, or can be arranged at an arbitrary angle. Further, the plan view refers to viewing the object from the normal direction of one surface 11a of the semiconductor substrate 11 described later, and the planar shape refers to the normal line of one surface 11a of the semiconductor substrate 11 described later. It shall refer to the shape viewed from the direction.

  In each figure, the normal direction of one surface 11a of the semiconductor substrate 11 is the Z direction, and the direction parallel to one side of the one surface 11a of the semiconductor substrate 11 in plan view is perpendicular to the X direction, the X direction, and the Z direction. This direction is the Y direction.

  Here, the surface emitting laser array substrate 10 and the microlens array substrate 20 will be described in detail with reference to FIGS. 2 and 3. 2A and 2B are diagrams illustrating the surface emitting laser array substrate according to the first embodiment. FIG. 2A is a plan view, and FIG. 2B is a line AA in FIG. It is sectional drawing which follows. In addition, in the plan view of FIG. 2A, each part is shown with a satin pattern for convenience (the same applies to other plan views).

  In the surface emitting laser array substrate 10, a surface emitting laser array 12 is formed at a substantially central portion of one surface 11a (upper surface) of a semiconductor substrate 11 made of n-type gallium arsenide (GaAs) or the like. The surface emitting laser array 12 includes a plurality of surface emitting lasers (not shown), which are unit elements having a mesa structure, arranged in a one-dimensional or two-dimensional array. The planar shape of the semiconductor substrate 11 is, for example, a quadrangle. The surface emitting laser (not shown) is, for example, a VCSEL (Vertical Cavity Surface Emitting Laser) that emits light in a direction perpendicular to the semiconductor substrate 11 (Z direction).

  In the surface emitting laser array substrate 10, an anode electrode 13 obtained by extending an anode electrode of each surface emitting laser (not shown) which is a unit element constituting the surface emitting laser array 12 is provided on one surface 11 a of the semiconductor substrate 11. Is formed. A cathode electrode (not shown) is formed on the other surface 11 b (lower surface) of the semiconductor substrate 11.

  Adhesive fixing regions 14 are formed at, for example, the four corners of one surface 11a of the semiconductor substrate 11. The height from one surface 11a of the semiconductor substrate 11 to the upper surface of the adhesive fixing region 14 is approximately the same as the height from one surface 11a of the semiconductor substrate 11 to the light emitting point of the surface emitting laser. The adhesive fixing region 14 is a typical example of the first adhesive fixing region according to the present invention. The four corners of the one surface 11a of the semiconductor substrate 11 mean the vicinity of the corners of the one surface 11a of the semiconductor substrate 11, and the adhesive fixing region 14 is not necessarily the edge of the one surface 11a of the semiconductor substrate 11. It may not be provided so that it may touch.

  The planar shape of the adhesive fixing region 14 can be, for example, a square. The adhesive fixing region 14 can be formed of, for example, gold (Au). For example, the adhesive fixing region 14 may be formed of a laminated film in which titanium (Ti) / platinum (Pt) / gold (Au) are laminated in this order from the one surface 11a side of the semiconductor substrate 11. However, the adhesive fixing region 14 may be formed of a material other than the above as long as the material is more easily wetted with the adhesive 30 than the material (for example, gallium arsenide) constituting the semiconductor substrate 11.

  Since the semiconductor substrate 11 has low conductivity, the anode electrode 13 and the adhesive fixing region 14 formed on the one surface 11a of the semiconductor substrate 11 so as to be separated from each other are electrically insulated. When it is desired to more reliably insulate the anode electrode 13 and the adhesive fixing region 14, an insulating film may be formed on one surface 11 a of the semiconductor substrate 11 and the adhesive fixing region 14 may be formed thereon.

  3A and 3B are diagrams illustrating the microlens array substrate according to the first embodiment. FIG. 3A is a plan view, and FIG. 3B is along the line BB in FIG. It is sectional drawing.

  In the microlens array substrate 20, a microlens array 22 is formed on a transparent substrate 21 made of synthetic quartz or the like. Each microlens constituting the microlens array 22 is disposed at a position corresponding to each surface emitting laser (not shown) which is a unit element constituting the surface emitting laser array 12. The light emitted from each surface emitting laser (not shown), which is a unit element, enters a corresponding microlens and is converted into parallel light.

  For example, at four corners of the facing surface 21a that is the surface facing the surface emitting laser array substrate 10 of the transparent substrate 21, bridge piers 23 for defining the distance from the surface emitting laser array substrate 10 extend from the transparent substrate 21. Is formed. An adhesive fixing region 24 is formed on the bottom surface of the pier 23. The adhesive fixing region 24 is a typical example of the second adhesive fixing region according to the present invention. In addition, as long as each adhesive fixing area | region 24 is formed in the position facing each adhesive fixing area | region 14, it does not necessarily need to be formed in the whole surface of the bottom face of the bridge pier part 23. FIG.

  The planar shape of the adhesive fixing region 24 is preferably equal to the planar shape of the adhesive fixing region 14. The adhesive fixing region 24 can be formed from the same material as the adhesive fixing region 14, for example. However, the adhesive fixing region 24 may be formed of a material other than the above as long as the material is more easily wetted with the adhesive 30 than the material constituting the pier 23 (the same as the material constituting the transparent substrate 21). Good.

  As described above, the microlens array substrate 20 includes the microlens array 22 on which the light emitted from each surface emitting laser is incident, the plurality of bridge piers 23 protruding toward the one surface 11a of the semiconductor substrate 11, and the respective piers 23. Are provided with an adhesive fixing region 24 formed on the bottom surface.

  1 and 3, the microlens array 22 is formed on the opposing surface 21a of the transparent substrate 21 (the surface on which the bridge piers 23 are formed). However, the microlens array 22 is not necessarily limited to the opposing surface 21a. It does not have to be formed. For example, the microlens array 22 may be formed on the surface of the transparent substrate 21 opposite to the facing surface 21a.

  Returning to FIG. 1, the adhesive fixing region 14 of the surface emitting laser array substrate 10 and the adhesive fixing region 24 of the microlens array substrate 20 facing the surface fixing laser array substrate 10 are bonded via bumps made of an adhesive 30. As the adhesive 30, an adhesive mainly composed of gold having a large surface tension, for example, Au—Sn (20 wt%) can be suitably used. However, as the adhesive 30, Sn-Cu, Sn-Sb, Sn-Ag, Sn-Bi, etc., which are generally used lead-free solder materials, may be used.

  In the case of a material containing flux, the flux may scatter to the microlens array 22 or the like at the time of bonding, which may cause a decrease in the amount of light, etc. Therefore, a step of cleaning the flux after bonding is necessary. By using a material that does not contain a flux such as Au—Sn, it is not necessary to provide a flux cleaning step, so that the manufacturing process can be simplified.

  The surface emitting laser array substrate 10 and the microlens array substrate 20 are fixed in a self-aligned (self-aligned) state by a restoring force generated when the adhesive 30 is melted. The self-alignment will be described in detail in the method for manufacturing the surface emitting laser device 1 described later.

  The positional accuracy of each surface emitting laser of the surface emitting laser array substrate 10 and each microlens of the microlens array substrate 20 in the self-alignment in the plane direction and the height direction (horizontal direction and vertical direction) is about ± 1 μm. can do.

  In FIG. 1, for the sake of convenience, the surface-emitting laser array substrate 10 has a cross section corresponding to FIG. 2, and the microlens array substrate 20 has a cross section corresponding to FIG.

[Method for Manufacturing Surface Emitting Laser Device]
4 to 7 are diagrams illustrating the manufacturing process of the surface emitting laser device according to the first embodiment. First, as shown in FIG. 4A, a surface emitting laser array 12 is formed at a substantially central portion of one surface 11a of a semiconductor substrate 11, and metal is used at four corners of one surface 11a of the semiconductor substrate 11. A plurality of adhesion fixing regions 14 are formed, and the surface emitting laser array substrate 10 is manufactured. Then, Au—Sn (20 wt%) is disposed as the adhesive 30 on the adhesive fixing regions 14 at the four corners of the one surface 11 a of the semiconductor substrate 11 of the manufactured surface emitting laser array substrate 10. A predetermined amount of Au—Sn (20 wt%) is arranged on the adhesive fixing region 14 by using, for example, a vacuum deposition method. Alternatively, an appropriate amount of Au—Sn (20 wt%) foil may be cut out and placed on the adhesive fixing region 14.

  The structure of the surface emitting laser array substrate 10 is as described with reference to FIG. In order to form the surface emitting laser array 12, first, the semiconductor substrate 11 is prepared. Then, for example, a lower DBR (Distributed Bragg Reflector) reflector, a lower spacer layer, a multiple quantum well active layer, an upper spacer layer, an upper DBR reflector, and a contact layer (not shown) are sequentially epitaxially grown on one surface 11a of the semiconductor substrate 11. Etc. are laminated.

  Then, a mesa structure is formed by etching the laminated semiconductor layer in a predetermined region in a direction perpendicular to one surface 11a of the semiconductor substrate 11, and an insulator film is formed on the side surface of the mesa structure and the etched region. To do. As a result, the surface emitting laser array 12 that emits laser light in the Z direction from the emission surface that is open on the upper surface of the mesa structure is formed.

  The adhesive fixing region 14 can be formed by depositing gold (Au) or the like on the one surface 11a of the semiconductor substrate 11 by vacuum vapor deposition or EB (Electron Beam) vapor deposition, for example. The adhesion fixing region 14 is formed by, for example, laminating titanium (Ti) / platinum (Pt) / gold (Au) sequentially from one surface 11a side of the semiconductor substrate 11 by vacuum deposition or EB (Electron Beam) deposition. May be.

  By the way, in order to achieve highly accurate alignment by self-alignment in the subsequent process, it is important to increase the positional accuracy of each light emitting point (mesa structure) of each surface emitting laser array 12 and each adhesive fixing region 14. is there. One mask is required to form a mesa structure by etching. Further, another mask is required to form the adhesive fixing region 14 by vacuum deposition or the like (the anode electrode 13 is also formed with the same mask). In other words, each light emitting point (mesa structure) of the surface emitting laser array 12 and each adhesive fixing region 14 have high positional accuracy determined by the mask alignment accuracy of the two masks.

  Next, as shown in FIG. 4B, a heat sink substrate 50 on which the surface emitting laser array substrate 10 is mounted is prepared. The heat sink substrate 50 is insulative, and a wiring pattern 51 for mounting the cathode electrode of the surface emitting laser array substrate 10 and a wiring pattern 52 for wire bonding the anode electrode 13 are formed on the surface. A current terminal 53 is connected to the wiring pattern 51, and a current terminal 54 is connected to the wiring pattern 52. The wiring patterns 51 and 52 can be formed from, for example, gold (Au) or the like. Further, the current terminals 53 and 54 can be formed from, for example, copper (Cu) or the like. The current terminals 53 and 54 may be formed in a later process.

  Next, as shown in FIG. 5A, the surface emitting laser array substrate 10 in which the adhesive 30 is disposed on the adhesive fixing region 14 is fixed to the wiring pattern 51 of the heat sink substrate 50 with a die bonding agent (die bonding). . Next, as shown in FIG. 5B, the anode electrode 13 of the die-bonded surface emitting laser array substrate 10 and the wiring pattern 52 of the heat sink substrate 50 are connected (wire bonding) using a metal wire 55. As the metal wire 55, for example, a gold wire or a copper wire can be used.

  Next, as shown in FIG. 6A, a microlens array substrate 20 is produced. The produced microlens array substrate 20 is held in the air with vacuum tweezers or the like, and is brought into a state in which it can be precisely moved in the XY direction (horizontal direction). 6A to 7A, only the surface emitting laser array substrate 10, the microlens array substrate 20, and the adhesive 30 are illustrated, and other members are not illustrated.

  The structure of the microlens array substrate 20 is as described with reference to FIG. The microlens array 22 and the bridge pier part 23 can be formed by a well-known method combining photolithography and etching using, for example, quartz. The adhesive fixing region 24 can be formed by the same material and method as the adhesive fixing region 14.

  By the way, in order to achieve highly accurate alignment by self-alignment in the subsequent process, it is important to increase the positional accuracy of each microlens and each adhesive fixing region 24 of the microlens array 22. In order to form a microlens by etching, one mask is required. Further, another mask is required to form the adhesive fixing region 24 by vacuum deposition or the like. That is, each microlens of the microlens array 22 and each adhesive fixing region 24 have high positional accuracy determined by the mask alignment accuracy of the two masks.

  Next, as shown in FIG. 6B, the position of the microlens array substrate 20 held in the air is adjusted, and the adhesive fixing region 24 of the microlens array substrate 20 is surface-emitting laser through the adhesive 30. It arrange | positions so that it may come to the position facing the adhesion fixing area | region 14 of the array substrate 10. At this time, there may be a positional shift between the microlens array substrate 20 and the surface emitting laser array substrate 10.

  Next, as shown in FIGS. 7A and 7B, the microlens array substrate 20 is fixed to the surface emitting laser array substrate 10 via an adhesive 30. 7A is a cross-sectional view illustrating only the surface emitting laser array substrate 10, the microlens array substrate 20, and the adhesive 30, and FIG. 7B is an entire surface emitting laser device 1 mounted on the heat sink substrate 50. It is the top view which illustrated.

  Specifically, for example, heating is performed at 280 ° C. or more in a nitrogen atmosphere, and Au—Sn (20 wt%) as the adhesive 30 is melted. The melted Au—Sn (20 wt%) wets and spreads in the adhesive fixing region 14 of the surface emitting laser array substrate 10 and the adhesive fixing region 24 of the microlens array substrate 20.

  At this time, self-alignment (self-alignment) occurs due to the restoring force of the molten Au—Sn (20 wt%), and the microlens array substrate 20 is aligned with respect to the surface emitting laser array substrate 10 with high accuracy. Further, by making the amount of Au—Sn (20 wt%) arranged between each adhesive fixing region 14 and adhesive fixing region 24 uniform, the positional accuracy in the height direction can be ensured.

  Thereafter, the mounting of the microlens array substrate 20 is completed through a cooling process. That is, the surface emitting laser array substrate 10 and the microlens array substrate 20 are fixed in a state where the adhesive 30 is solidified and aligned with high accuracy after self-alignment with each other by the restoring force of the molten adhesive 30. The

  The positional accuracy of each surface emitting laser of the surface emitting laser array substrate 10 and each microlens of the microlens array substrate 20 in the self-alignment in the plane direction and the height direction (horizontal direction and vertical direction) is about ± 1 μm. can do. In addition, about ± 1 μm means the positional deviation between each light emitting point of the surface emitting laser array 12 and each adhesive fixing region 14 determined by the mask alignment accuracy of the two masks, and each microlens of the microlens array 22. And a value including a positional deviation of each adhesive fixing region 24.

  In the process shown in FIGS. 7A and 7B, when the adhesive 30 is melted, the entire surface emitting laser array substrate 10, the microlens array substrate 20, and the adhesive 30 are heated rather than being heated. It is preferable to heat only the agent 30 locally. Thermal stress resulting from the difference in thermal expansion coefficient between the microlens array substrate 20 (for example, quartz) and the semiconductor substrate 11 (for example, gallium arsenide) that constitutes the surface emitting laser array substrate 10 remains on the semiconductor substrate 11. This is to prevent it.

  For example, it is possible to use a heating device that deflects laser light emitted from a laser light source by a galvanometer mirror and sequentially and repeatedly irradiates four adhesives 30. A plurality of laser light sources or a plurality of galvanometer mirrors may be used. Thereby, the adhesive 30 is heated locally and simultaneously, and the problem resulting from the difference in the thermal expansion coefficient can be avoided.

  In the above description, an example in which an Au—Sn vapor deposition film or the like is used as an adhesive that is expected to have a self-alignment effect is shown. However, an Au—Sn paste can also be used as the adhesive 30. . Below, the manufacturing process at the time of using Au-Sn paste as the adhesive agent 30 is demonstrated easily. Note that the Au—Sn paste contains a flux.

  First, a process of extending the Au—Sn paste to a uniform thickness on a predetermined plane is performed. Next, the adhesive fixing region 24 of the microlens array substrate 20 is brought into contact with the uniformly stretched Au—Sn paste, and the Au—Sn paste is uniformly transferred to the adhesive fixing region 24. Next, the Au—Sn paste transferred to the adhesive fixing region 24 is cured by performing a heat treatment at 280 ° C. or higher in a nitrogen atmosphere. Next, the flux remaining in the adhesive fixing region 24 is cleaned with a cleaning liquid.

  Next, the microlens array substrate 20 having the Au—Sn paste transferred to the adhesive fixing region 24 is disposed at a predetermined position of the surface emitting laser array substrate 10, and Au— is reheated in a nitrogen atmosphere to prevent Sn oxidation. The Sn paste is melted and then cured. At this time, the surface-emitting laser array substrate 10 and the microlens array substrate 20 are fixed in a highly aligned state by self-alignment. The positional accuracy of the self-alignment is the same as that when an Au—Sn vapor deposition film or the like is used.

  Here, the principle of performing self-alignment in the steps shown in FIGS. 7A and 7B will be described. FIG. 8 is a partially enlarged cross-sectional view in the vicinity of the molten adhesive 30. As shown in FIG. 8, a restoring force F acts on the adhesive 30 that has been melted and liquefied by surface tension. By this restoring force F, the microlens array substrate 20 is self-aligned.

  Thereafter, the mounting of the microlens array substrate 20 is completed through a cooling process. That is, the surface emitting laser array substrate 10 and the microlens array substrate 20 are fixed in a state where the adhesive 30 is solidified and aligned with high accuracy after self-alignment with each other by the restoring force F of the molten adhesive 30. Is done.

  The restoring force F acts so that the contact angles become equal due to the surface tension of the adhesive 30 spread wet. Specifically, the restoring force F can be expressed by the following formula (1).

F = L × γ × cosθ (1)
Here, L is the length of the side where the adhesive 30 is wet, θ is the contact angle, and γ is the surface tension. As shown in Expression (1), the restoring force F received by the microlens array substrate 20 is larger as the length L of the side where the adhesive 30 is wet is longer, as the surface tension γ is larger, and as the contact angle θ is smaller. Large value. Therefore, it is preferable that the shape of the region where the adhesive 30 gets wet (the planar shape of the adhesive fixing regions 14 and 24) is a square, a rectangle, or a combination of a square and a rectangle rather than a circle.

<Second Embodiment>
In the second embodiment, an example of a surface emitting laser device in which the planar shape of the adhesive fixing region is different from that of the first embodiment will be described. In the second embodiment, description of the same components as those of the already described embodiments may be omitted.

  As described above, the planar shape of the region where the adhesive 30 gets wet is preferably a square, a rectangle, or a combination of a square and a rectangle rather than a circle. In the first embodiment, the planar shape of the adhesive fixing region 14 is square, but in the surface emitting laser array substrate 10A shown in FIG. 9, the planar shape of the adhesive fixing region 14A is rectangular. The adhesive fixing regions 14 </ b> A arranged at the four corners have a pattern that alternately repeats vertical and horizontal along the outer shape of the semiconductor substrate 11.

  That is, in the adhesive fixing regions 14A arranged at the four corners, the adjacent adhesive fixing regions 14A are arranged in a positional relationship in which the long sides are orthogonal to each other. In other words, in the adhesive fixing regions 14A arranged at the four corners, the diagonal adhesive fixing regions 14A are arranged in a positional relationship in which the long sides are parallel to each other. Although not shown, the adhesion fixing area of the microlens array substrate is also formed in a planar shape (that is, a rectangle) corresponding to the adhesion fixing area 14A, and is disposed at a position corresponding to the adhesion fixing area 14A.

  From the equation (1), the restoring force F works more in the long side direction of the rectangle. Therefore, due to the arrangement of the adhesive fixing region 14A as shown in FIG. 9, the restoring force F received from the adjacent adhesive 30 by the microlens array substrate at the time of self-alignment is orthogonal. As a result, it is possible to effectively align the rotational displacement of the microlens array substrate with respect to the surface emitting laser array substrate 10A.

<Third Embodiment>
In the third embodiment, another example of the surface emitting laser device in which the planar shape of the adhesive fixing region is different from that of the first embodiment will be described. Note that in the third embodiment, description of the same components as those of the already described embodiments may be omitted.

  As described above, the shape of the region where the adhesive 30 gets wet is preferably a square, a rectangle, or a combination of a square and a rectangle rather than a circle. In the first embodiment, the planar shape of the adhesive fixing region 14 is square, and in the second embodiment, the planar shape of the adhesive fixing region 14A is rectangular. On the other hand, in the surface emitting laser array substrate 10B shown in FIG. 10, the planar shape of the adhesive fixing region 14B is L-shaped (a combination of squares and rectangles). The adhesive fixing regions 14 </ b> B arranged at the four corners have a pattern in which the L-shaped inner side faces the center side of the semiconductor substrate 11. The long part and the short part of the L shape may have the same length.

  Although not shown, the adhesion fixing area of the microlens array substrate is also formed in a planar shape (that is, an L shape) corresponding to the adhesion fixing area 14B, and is disposed at a position corresponding to the adhesion fixing area 14B.

  With the arrangement of the adhesive fixing region 14B as shown in FIG. 10, the restoring force F received from the adjacent adhesive 30 by the microlens array substrate during self-alignment has a component parallel to the orthogonal component. As a result, it is possible to effectively align the rotational displacement of the microlens array substrate with respect to the surface emitting laser array substrate 10B and the displacement in the XY direction.

<Fourth embodiment>
In the fourth embodiment, an example of a surface emitting laser device in which the shape of the microlens array substrate is different from that in the first embodiment will be described. Note that in the fourth embodiment, descriptions of the same components as those of the above-described embodiments may be omitted.

  11A and 11B are diagrams illustrating a microlens array substrate according to the fourth embodiment. FIG. 11A is a plan view, and FIG. 11B is along the line CC in FIG. 11A. It is sectional drawing.

  The microlens array substrate is made of, for example, quartz, and the semiconductor substrate constituting the surface emitting laser array substrate is made of, for example, gallium arsenide. Therefore, when the microlens array substrate is bonded to the surface emitting laser array substrate with an adhesive, there is a concern that thermal stress due to the difference in thermal expansion coefficient between the two remains on the semiconductor substrate.

  Therefore, in the microlens array substrate 20C shown in FIG. 11, hinges 25 extending from the four corners of the transparent substrate 21 (portions where the microlens array 22 is formed) in a direction parallel to the one surface 11a of the semiconductor substrate 11 are provided. It has been.

  The planar shape of the hinge 25 can be L-shaped, for example. In this case, in the plan view, each hinge 25 has an L-shaped short portion connected to each corner of the transparent substrate 21 and an L-shaped long portion connected to the side of the transparent substrate 21 connected to the short portion. It can arrange | position so that it may leave | separate and may become parallel. Each hinge 25 can be arranged to be rotationally symmetric in plan view.

  At one end of the L-shaped long portion of the hinge 25, a bridge pier 23 protruding toward the one surface 11a of the semiconductor substrate 11 is formed extending in the Z direction, and an adhesive fixing region 24 is formed at the bottom of the bridge pier 23. Has been. Although not shown, the adhesive fixing region of the surface emitting laser array substrate is also formed in a planar shape corresponding to the adhesive fixing region 24 of the microlens array substrate 20C, and is disposed at a position corresponding to the adhesive fixing region 24.

  Thus, by supporting the microlens array substrate 20C with the four hinges 25, it becomes possible to relieve the thermal stress at the time of bonding, and configure the surface emitting laser array substrate due to the difference in thermal expansion coefficient. The stress remaining on the semiconductor substrate can be reduced.

<Fifth embodiment>
In the fifth embodiment, an example of a surface emitting laser device in which an opening is provided in an adhesive fixing region of a microlens array substrate will be described. Note that in the fifth embodiment, description of the same components as those of the above-described embodiments may be omitted.

  FIG. 12 is a cross-sectional view illustrating the main part of the surface emitting laser apparatus according to the fifth embodiment. As shown in FIG. 12, the surface-emitting laser device 1D is different from the surface-emitting laser device 1 in that the adhesive fixing region 24D is provided on the bottom surface of the pier portion 23 of the microlens array substrate 20 instead of the adhesive fixing region 24. 1)). The adhesive fixing region 24D is provided with an opening 240 that penetrates the adhesive fixing region 24D in the thickness direction.

  FIG. 13 is a plan view illustrating an adhesion fixing region of the surface emitting laser device according to the fifth embodiment. As shown to Fig.13 (a), the planar shape of the opening part 240 can be made into a square or a rectangle, for example. Further, as shown in FIG. 13B, the planar shape of the opening 240 may be, for example, a circle or an ellipse. Moreover, as shown in FIG.13 (c), the opening part 240 may be reached to an edge part, for example, it is good also as the adhesive fixing area | region 24D whose planar shape is a U-shape.

  Alternatively, the planar shape of the opening 240 may be a more complicated shape other than that shown in FIG. 13 (for example, a shape combining a square and a circle). A plurality of openings 240 may be provided in one adhesive fixing region 24D (for example, two circular openings). At that time, the plurality of openings 240 may have different shapes (for example, a mixture of square openings and circular openings).

  Next, the technical significance of providing the opening 240 in the adhesive fixing region 24D will be described with reference to FIG. FIG. 14 is a diagram illustrating a manufacturing process of the surface emitting laser device according to the fifth embodiment.

  As described above, when the adhesive 30 is melted, it is preferable to locally heat only the adhesive 30. For example, a method of irradiating the adhesive 30 with laser light can be employed.

  By the way, in the first embodiment, when the adhesive 30 (solder, Au—Sn, etc.) is locally heated with laser light, the laser light is incident on the adhesive fixing region 24 from the transparent microlens array substrate 20 side. Can be considered. However, when laser light is incident on the adhesive fixing region 24 from the microlens array substrate 20 side, the reflection is large, and in order to melt the adhesive 30, more energy is required than when laser is directly incident on the adhesive 30. Expected to be needed.

  In this case, first, the laser beam heats the adhesive fixing region 24, and then the heat is transferred from the adhesive fixing region 24 to the lower adhesive 30, whereby the adhesive 30 is melted. Therefore, in a state where the adhesive 30 is melted, the temperature of the adhesive fixing region 24 becomes equal to or higher than the melting point of the adhesive 30 and the thermal stress increases.

  Therefore, in the present embodiment, in order to more efficiently melt the adhesive 30 with the laser light, the microlens array substrate 20 is replaced with the adhesive fixing region 24 so that the laser light is directly incident on the adhesive 30. Thus, an adhesive fixing region 24D having an opening 240 is provided.

  By providing the opening 240 in the adhesive fixing region 24D, as shown in FIG. 14A, the laser light La emitted from the heating device is opened from the microlens array substrate 20 side to the opening 240 of the adhesive fixing region 24D. And directly enters the adhesive 30. As a result, the adhesive 30 can be efficiently dissolved. Moreover, since the length of the interface with the adhesive 30 is increased by providing the opening 240 in the adhesive fixing region 24D, it can be expected that the surface tension increases.

  Thereby, as shown in FIG. 14B, the surface emitting laser array substrate 10 and the microlens array substrate 20 are self-aligned with each other by the restoring force of the molten adhesive 30, and then the adhesive 30 is solidified. It is fixed in a more precise aligned state.

  Thus, in the fifth embodiment, since the opening 240 is provided in the adhesive fixing region 24D of the microlens array substrate 20, the adhesive 30 can be efficiently melted by the laser light. Therefore, the temperature rise of the microlens array substrate 20 is suppressed, the thermal stress is reduced, and the length of the interface between the adhesive fixing region 24D and the adhesive 30 is increased, thereby increasing the surface tension and self-alignment. Accuracy can be improved.

  The preferred embodiment has been described in detail above. However, the present invention is not limited to the above-described embodiment, and various modifications and replacements are made to the above-described embodiment without departing from the scope described in the claims. Can be added.

  For example, in the above embodiment, the surface emitting laser device including the surface emitting laser array substrate and the microlens array substrate has been described. However, the present invention relates to the surface emitting laser device including the surface emitting laser substrate and the microlens substrate. It is also applicable to. That is, in the surface emitting laser device according to the present invention, the surface emitting laser and the microlens may be either one or plural.

DESCRIPTION OF SYMBOLS 1, 1D surface emitting laser apparatus 10, 10A, 10B Surface emitting laser array substrate 11 Semiconductor substrate 11a One surface of a semiconductor substrate 11b The other surface of a semiconductor substrate 12 Surface emitting laser array 13 Anode electrode 14, 14A, 14B, 24, 24D Adhesive fixing region 20, 20C Microlens array substrate 21 Transparent substrate 21a Opposing surface 22 Microlens array 23 Bridge pier 25 Hinge 30 Adhesive 50 Heat sink substrate 51, 52 Wiring pattern 53, 54 Current terminal 55 Metal wire 240 Opening

JP 2007-142425 A JP 2004-288713 A JP 2002-26452 A

Claims (14)

A surface emitting laser substrate in which a surface emitting laser and a plurality of first adhesive fixing regions are formed on one surface of the semiconductor substrate;
Formed at a position facing the first adhesive fixing region on the bottom surface of each of the micro piers projecting to one surface side of the semiconductor substrate, and the bottom surface of each micro pier, the micro lens on which the light emitted from the surface emitting laser enters. A microlens substrate provided with a second adhesive fixing region,
An adhesive that bonds the first adhesive fixing region and the second adhesive fixing region;
The surface-emitting laser device, wherein the surface-emitting laser substrate and the microlens substrate are fixed in a self-aligned state by a restoring force generated when the adhesive is melted. The first adhesive fixing region is formed of a material that is more easily wetted with the adhesive than the material constituting the semiconductor substrate,
2. The surface emitting laser device according to claim 1, wherein the second adhesion fixing region is formed of a material that is more easily wetted with respect to the adhesive than a material constituting the pier portion. The first adhesive fixing region is formed in the manufacturing process of the surface emitting laser,
3. The surface emitting laser device according to claim 1, wherein the bridge pier portion and the second adhesive fixing region are formed in a manufacturing process of the microlens.   The positional accuracy between the light emitting point of the surface emitting laser and the first adhesive fixing region is determined by the mask alignment accuracy between the mask used for manufacturing the surface emitting laser and the mask used for manufacturing the first adhesive fixing region. The surface emitting laser device according to claim 3.   The position accuracy between the microlens and the second adhesive fixing region is determined by mask alignment accuracy between a mask used for manufacturing the microlens and a mask used for manufacturing the second adhesive fixing region. 4. The surface emitting laser device according to 4. The planar shape of the semiconductor substrate is a rectangle,
A plurality of the first adhesive fixing regions are disposed at four corners of the semiconductor substrate,
The planar shape of each of the first adhesive fixing regions is a rectangle,
The adjacent first adhesive fixing regions are arranged in a positional relationship in which the long sides are orthogonal to each other,
Each said 2nd adhesion fixing area | region is formed in the planar shape corresponding to the said 1st adhesion fixing area | region, and is arrange | positioned in the position corresponding to the said 1st adhesion fixing area | region. The surface emitting laser device described. The planar shape of the semiconductor substrate is a rectangle,
A plurality of the first adhesive fixing regions are disposed at four corners of the semiconductor substrate,
The planar shape of each of the first adhesive fixing regions is L-shaped,
Each of the first adhesive fixing regions is arranged so that the L-shaped inner side faces the center side of the semiconductor substrate,
Each said 2nd adhesion fixing area | region is formed in the planar shape corresponding to the said 1st adhesion fixing area | region, and is arrange | positioned in the position corresponding to the said 1st adhesion fixing area | region. The surface emitting laser device described.   8. The height from one surface of the semiconductor substrate to the upper surface of the first adhesion fixing region is the same as the height from one surface of the semiconductor substrate to the light emitting point of the surface emitting laser. The surface emitting laser device according to any one of the above. The microlens substrate is provided with a plurality of hinges extending in a direction parallel to one surface of the semiconductor substrate from a portion where the microlens is formed,
9. The surface emitting laser device according to claim 1, wherein the bridge piercing portion that protrudes toward one surface of the semiconductor substrate is formed at one end of each of the hinges. 10.   The surface emitting laser according to claim 1, wherein a plurality of the surface emitting lasers and the microlenses are formed, and each of the surface emitting lasers and each of the microlenses are arranged at corresponding positions. Laser device.   The surface emitting laser device according to claim 1, wherein an opening is provided in the second adhesive fixing region. Forming a surface emitting laser substrate including a step of forming a surface emitting laser on one surface of the semiconductor substrate, a step of forming a plurality of first adhesive fixing regions on one surface of the semiconductor substrate,
Forming a microlens and a plurality of bridge piers on which a light emitted from the surface emitting laser is incident on a transparent substrate, a plurality of second adhesive fixings at positions corresponding to the first adhesive fixing region on the bottom surface of each of the bridge piers; Forming a region, forming a microlens substrate, and
Bonding the first adhesive fixing region and the second adhesive fixing region with an adhesive,
The bonding step includes
Disposing the adhesive in each of the first adhesive fixing regions or each of the second adhesive fixing regions;
Disposing the microlens substrate on the surface emitting laser substrate such that each of the second adhesive fixing regions faces each of the first adhesive fixing regions via the adhesive;
Melting the adhesive and self-aligning the surface-emitting laser substrate and the microlens substrate by the restoring force of the adhesive;
Cooling the adhesive, and fixing the microlens substrate on the surface-emitting laser substrate with the adhesive.   The method of manufacturing a surface emitting laser device according to claim 12, wherein the adhesive is melted by using a heating device that locally and simultaneously heats the plurality of adhesives. An opening is provided in the second adhesive fixing region;
The heating device is a device that emits laser light,
In the self-alignment step, the laser light emitted from the heating device is incident on the adhesive directly from the microlens substrate side through the opening of the second adhesive fixing region. The method for manufacturing a surface emitting laser device according to claim 13, wherein the surface emitting laser device is melted.

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