JP6536004B2 - Surface emitting laser device and method of manufacturing the same - Google Patents

Description

  The present invention relates to a surface emitting laser device and a method of manufacturing the same.

  In recent years, research on high-power lasers such as various optical devices, laser projectors, light source lasers for laser processing machines, etc. has been actively conducted. In such a high power laser, for example, the light of a 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 of its light emission in the direction perpendicular to the substrate, easy integration, and easy inspection. As a configuration of the high output laser, for example, one in which a collimator lens composed of a micro lens array is disposed in the light emission direction of a surface emitting laser array which is a light source, and a condenser lens is further disposed.

  The surface emitting laser array has a configuration in which, for example, surface emitting lasers having a mesa structure of several 10 μm square as a unit element are arranged in a square or hexagonal close-packed lattice. On the other hand, the microlens array for converting the light emitted from the surface emitting laser array into 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 microlens array configuration, in order to increase the light utilization efficiency of the surface emitting laser, high mounting accuracy of ± several μm in three directions of XYZ for mounting the microlens to the surface emitting laser Is required. Therefore, various studies have been made to improve the mounting accuracy of the microlens with respect to the surface emitting laser. Specific examples of the prior art for aligning the microlenses with high accuracy to the surface emitting laser will be shown below.

  A photonic device can be mentioned as a first example of the prior art for aligning the microlenses with high accuracy to the 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 made possible by fixing the legs integrated with the microlens structure to the substrate surface on which the surface emitting laser is formed. For alignment in the X and Y directions, 2) position adjustment method while observing the image of the surface emitting laser and the lens, and 2) position adjustment method while emitting light from the surface emitting laser array and receiving light transmitted through the lens. A type is disclosed (see, for example, Patent Document 1).

  An optical element mounting apparatus can be mentioned as a second example of the prior art in which the microlenses are aligned with high accuracy to the surface emitting laser. In this optical element mounting apparatus, in order to enable highly accurate alignment in the XY and Z directions, the projections of the alignment reference portion are integrally formed on one surface of the microlens array substrate. Then, a depression of the alignment reference portion is formed also on the surface of one of the surface emitting laser array substrates, and by fitting the both alignment reference portions, high-precision mounting is possible.

  In this optical element mounting apparatus, the projections on the side of the microlens are integrally formed with the microlens at the time of molding the microlens resin, and the depressions on the surface emitting laser array side substrate are etched with high precision by the photolithography technology of the semiconductor process. To make. This ensures the mounting accuracy after assembly (see, for example, Patent Document 2).

A surface emitting light source can be mentioned as a third example of the prior art for mounting a microlens with high accuracy to a surface emitting laser. In this surface emitting light source, microlenses are formed on the surface emitting laser array substrate corresponding to each surface emitting laser which is a unit element. The micro lens is manufactured by aligning the surface emitting laser and the micro lens with high accuracy by molding a dielectric such as SiO ₂ formed on the surface of the surface emitting laser into the micro lens by the photolithography technology. (See, for example, Patent Document 3).

  However, in the first example of the prior art, a complicated and expensive mounting apparatus is required to carry out the above two types of alignment methods, and there is a drawback that the mounting tact is slow. That is, it has been difficult to align the microlens with high accuracy to the surface emitting laser by a simple method.

  Further, in the second example of the prior art, the height of the projections and the depth of the depressions are at most equal to or less than the thickness of the substrate, so both the heights of the projections and the depths of the depressions are several hundred μm or less. That is, the height of the projection is extremely low, the depth of the depression is extremely shallow, and there is a problem that the position is easily displaced as it is. Therefore, it is necessary to fix the microlens on the surface emitting laser with an adhesive, a brazing material, or the like, and there has been a problem that the positional deviation of the lens occurs in the process. That is, it has been difficult to align the microlens with high accuracy to the surface emitting laser by this method.

  Also, in the third example of the prior art, since the microlenses are formed directly from the dielectric or the like on the surface emitting laser array substrate, the stress from the dielectric of the microlens substrate degrades the reliability of the surface emitting laser. There were many technical issues to carry out. That is, it has been difficult to put the microlens into alignment with a surface emitting laser with high accuracy by this method.

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

This surface emitting laser device, a surface emitting with a surface emitting laser for emitting light disposed on the semiconductor substrate from the one surface side of the semiconductor substrate, and a plurality of first bonded region to said one surface A laser substrate, a micro lens on which the emitted light of the surface emitting laser is incident, a plurality of bridge legs projecting on one surface side of the semiconductor substrate, and the first adhesive fixing area of the bottom surface of each bridge base A microlens substrate provided with a second adhesive fixing area formed at a predetermined position, and an adhesive for adhering the first adhesive fixing area and the second adhesive fixing area, the first adhesive fixing The region is formed of a material that is more easily wettable to the adhesive than the material that configures the semiconductor substrate, and the second adhesion fixing region is more easily wettable to the adhesive than the material that configures the bridge leg Formed from material And requirements that you are.

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

FIG. 1 is a cross-sectional view illustrating the main part of a surface emitting laser device according to a first 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 substrate concerning a 1st embodiment. FIG. 7 is a first view of an example of manufacturing steps of the surface-emitting laser device of the first embodiment of the present invention; FIG. 16 is a second view of the example of the manufacturing process of the surface-emitting laser device of the first embodiment of the present invention; FIG. 16 is a third view of the example of the manufacturing process of the surface-emitting laser device of the first embodiment of the present invention; FIG. 16 is a fourth view of the example of the manufacturing process of the surface-emitting laser device of the first embodiment of the present invention; 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 concerning a 2nd embodiment. It is a top view which illustrates the surface emitting laser array substrate concerning a 3rd embodiment. It is a figure which illustrates the microlens array substrate concerning a 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 field of the surface emitting laser device concerning a 5th embodiment. It is a figure which illustrates the manufacturing process of the surface emitting laser apparatus which concerns on 5th Embodiment.

  Hereinafter, embodiments of the present 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. Further, the surface emitting laser array substrate 10 can be mounted, for example, on the surface of a heat sink (not shown).

  In the present embodiment, for convenience, the microlens array substrate 20 side is the upper side or one side, and the surface emitting laser array substrate 10 side is the lower side or the other side. Further, the surface on the side of the microlens array substrate 20 of each portion is referred to as one surface or the upper surface, and the surface on the surface emitting laser array substrate 10 side is referred to as the other surface or the lower surface. However, the surface emitting laser device 1 can be used in the upside-down state or can be disposed at an arbitrary angle. Further, planar view refers to viewing the object in the normal direction of one surface 11 a of the semiconductor substrate 11 described later, and planar shape refers to normal to the surface 11 a of the semiconductor substrate 11 described later. It refers to the shape viewed from the direction.

  In each drawing, the direction normal to one surface 11a of the semiconductor substrate 11 is the Z direction, and a direction parallel to one side of one surface 11a of the semiconductor substrate 11 in the plan view is perpendicular to the X direction, the X direction, and the Z direction. Direction is taken as 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. FIG. 2 is a view illustrating the surface emitting laser array substrate according to the first embodiment, and FIG. 2 (a) is a plan view, and FIG. 2 (b) is a line AA of FIG. 2 (a). FIG. In the plan view of FIG. 2A, each portion is shown in a textured pattern for the sake of convenience (the same applies to the other plan views).

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

  In the surface emitting laser array substrate 10, an anode electrode 13 in which an anode electrode of each surface emitting laser (not shown), which is a unit element constituting the surface emitting laser array 12, is extended on one surface 11a of the semiconductor substrate 11. It is formed. Further, on the other surface 11 b (lower surface) of the semiconductor substrate 11, a cathode electrode (not shown) is formed.

  In addition, adhesion fixing areas 14 are formed at, for example, four corners of one surface 11 a of the semiconductor substrate 11. The height from one surface 11 a of the semiconductor substrate 11 to the upper surface of the adhesive fixing area 14 is approximately the same as the height from one surface 11 a of the semiconductor substrate 11 to the light emitting point of the surface emitting laser. The adhesion fixing area 14 is a representative example of the first adhesion fixing area according to the present invention. The four corners of one surface 11 a of the semiconductor substrate 11 mean the vicinity of the corner of the one surface 11 a of the semiconductor substrate 11, and the adhesion fixing region 14 is not necessarily the edge of the one surface 11 a of the semiconductor substrate 11. It does not have to be provided in contact with

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

  Since the semiconductor substrate 11 has a low conductivity, the anode electrode 13 and the adhesion fixing area 14 which are formed apart from each other on one surface 11 a of the semiconductor substrate 11 are electrically insulated. If it is desired to insulate the anode electrode 13 and the adhesion fixing area 14 more reliably, an insulating film may be formed on one surface 11 a of the semiconductor substrate 11 and the adhesion fixing area 14 may be formed thereon.

  FIG. 3 is a view illustrating a microlens array substrate according to the first embodiment, and FIG. 3 (a) is a plan view, and FIG. 3 (b) is a line B-B in FIG. 3 (a). FIG.

  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 of the microlenses constituting the microlens array 22 is arranged 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, is incident on the corresponding microlens to be collimated light.

  At the four corners of the facing surface 21a, which is a surface facing the surface emitting laser array substrate 10 of the transparent substrate 21, for example, bridge portions 23 for defining the distance from the surface emitting laser array substrate 10 extend from the transparent substrate 21. It is formed. An adhesive fixing area 24 is formed on the bottom of the bridge leg 23. The adhesive fixing area 24 is a representative example of the second adhesive fixing area according to the present invention. Each adhesive fixing area 24 may not necessarily be formed on the entire bottom surface of the bridge leg 23 as long as it is formed at a position facing the adhesive fixing area 14.

  The planar shape of the adhesive fixing area 24 is preferably equal to the planar shape of the adhesive fixing area 14. The adhesive fixing area 24 can be formed, for example, from the same material as the adhesive fixing area 14. However, if the adhesion fixing area 24 is a material that is more easily wettable to the adhesive 30 than the material forming the bridge leg 23 (the same as the material forming the transparent substrate 21), the adhesion fixing area 24 may be formed of other materials. Good.

  As described above, the microlens array substrate 20 includes the microlens array 22 on which the emitted light of each surface emitting laser is incident, the plurality of bridge portions 23 projecting on the side of the surface 11 a of the semiconductor substrate 11, and the respective bridge portions 23. The adhesive fixing area 24 is formed on the bottom of the.

  In the example shown in FIGS. 1 and 3, the microlens array 22 is formed on the facing surface 21a of the transparent substrate 21 (the surface on which the bridge portion 23 is formed), but the microlens array 22 is not necessarily the facing 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 21 a.

  Returning to FIG. 1, the adhesion fixing area 14 of the surface emitting laser array substrate 10 and the adhesion fixing area 24 of the micro lens array substrate 20 opposed thereto are adhered via bumps made of an adhesive 30. As the adhesive 30, an adhesive based on gold having high 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 lead-free solder materials generally used may be used.

  In the case of a material containing flux, the flux may be scattered to the microlens array 22 or the like at the time of bonding to cause a reduction in the amount of light and the like, so a step of washing the flux after bonding is required. By using a material that does not contain flux, such as Au-Sn, it is not necessary to provide a flux cleaning step, so 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 the restoring force generated when the adhesive 30 is melted. The self alignment will be described in detail in the method of manufacturing the surface emitting laser device 1 described later.

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

  In FIG. 1, for convenience, a cross section corresponding to FIG. 2 is shown for the surface emitting laser array substrate 10, and a cross section corresponding to FIG. 3 for the microlens array substrate 20.

[Method of manufacturing surface emitting laser device]
4 to 7 are views illustrating manufacturing processes of the surface emitting laser device according to the first embodiment. First, as shown in FIG. 4A, the surface emitting laser array 12 is formed substantially at the center of one surface 11a of the semiconductor substrate 11, and metal is used at the four corners of the 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 adhesion fixing regions 14 at the four corners of one surface 11 a of the semiconductor substrate 11 of the manufactured surface emitting laser array substrate 10. Au-Sn (20 wt%) arrange | positions a predetermined amount on adhesion fixing area | region 14 using a vacuum evaporation method, for example. Alternatively, an appropriate amount of Au-Sn (20 wt%) foil may be cut out and disposed on the adhesion fixing area 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 The layers are formed in layers.

  Then, the semiconductor layer in the predetermined region formed by lamination is etched in a direction perpendicular to one surface 11 a of the semiconductor substrate 11 to form a mesa structure, and an insulator film is formed on the side surface of the mesa structure and the etched region. Do. As a result, the surface emitting laser array 12 is formed which emits laser light in the Z direction from the emission surface opened in the upper surface of the mesa structure.

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

  By the way, in order to achieve highly accurate alignment by self alignment in the post process, it is important to improve the positional accuracy of each light emitting point (mesa structure) of the surface emitting laser array 12 and each adhesive fixing area 14 is there. One mask is required to form a mesa structure by etching. In addition, another mask is required to form the bonding and fixing area 14 by vacuum deposition or the like (the anode electrode 13 is also formed by the same mask). That is, each light emitting point (mesa structure) of the surface emitting laser array 12 and each adhesion fixing area 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 insulating, 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. Further, the current terminal 53 is connected to the wiring pattern 51, and the current terminal 54 is connected to the wiring pattern 52. The wiring patterns 51 and 52 can be formed of, for example, gold (Au) or the like. Also, the current terminals 53 and 54 can be formed of, for example, copper (Cu) or the like. The current terminals 53 and 54 may be formed in a later step.

  Next, as shown in FIG. 5A, the surface emitting laser array substrate 10 having the adhesive 30 disposed on the adhesive fixing area 14 is fixed (die bonded) to the wiring pattern 51 of the heat sink substrate 50 by the die bonding agent. . Next, as shown in FIG. 5B, the anode electrode 13 of the surface-emitting laser array substrate 10 which has been die-bonded 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, the microlens array substrate 20 is manufactured. Then, the manufactured microlens array substrate 20 is held in the air by vacuum tweezers or the like so that it can be accurately 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 the other members are omitted.

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

  By the way, in order to achieve highly accurate alignment by self-alignment in a post process, it is important to improve the positional accuracy of each micro lens of micro lens array 22 and each adhesion fixation area 24. One mask is required to form a microlens by etching. In addition, another mask is required to form the adhesion fixing area 24 by vacuum deposition or the like. That is, each micro lens of the micro lens array 22 and each adhesion fixing area 24 have high positional accuracy determined by the mask alignment accuracy of the two masks.

  Next, as shown in FIG. 6 (b), position adjustment of the microlens array substrate 20 held in the air is carried out, and the adhesion fixing area 24 of the microlens array substrate 20 is a surface emitting laser through the adhesive 30. The array substrate 10 is disposed so as to face the adhesive fixing area 14 of the array substrate 10. At this time, positional deviation may occur 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 with the adhesive 30 interposed therebetween. 7 (a) 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. 7 (b) is the entire surface emitting laser device 1 mounted on the heat sink substrate 50. It is the top view which illustrated.

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

  At this time, self-alignment (self-alignment) occurs by the restoring force of the melted Au-Sn (20 wt%), and the microlens array substrate 20 is aligned with the surface emitting laser array substrate 10 with high accuracy. In addition, by making the amount of Au-Sn (20 wt%) disposed between the adhesive fixing regions 14 and the adhesive fixing regions 24 uniform, the positional accuracy in the height direction can be secured.

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

  The positional accuracy of each of the surface emitting lasers of the surface emitting laser array substrate 10 and the microlenses of the microlens array substrate 20 in the self alignment in the planar direction and 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 each surface emitting laser array 12 and each adhesion fixing area 14 determined by the mask alignment accuracy of the two masks described above, and each microlens of the microlens array 22 And the positional deviation of each adhesion fixation area 24 is also included.

  In the steps shown in FIGS. 7A and 7B, when the adhesive 30 is melted, the surface emitting laser array substrate 10, the microlens array substrate 20, and the adhesive 30 are all adhered together by heating. It is preferable to heat only the agent 30 locally. Thermal stress caused by the difference in thermal expansion coefficient between the microlens array substrate 20 (for example, quartz) and the semiconductor substrate 11 (for example, gallium arsenide) constituting the surface emitting laser array substrate 10 remains in the semiconductor substrate 11 It is to prevent.

  For example, it is possible to use a heating device which deflects laser light emitted from a laser light source by a galvano mirror and sequentially and repeatedly irradiates four adhesives 30. A plurality of laser light sources or a plurality of galvano mirrors may be used. This allows the adhesive 30 to be heated locally and at the same time, avoiding the problems caused by the differences in the thermal expansion coefficients described above.

  In the above description, an example in which an Au-Sn vapor deposition film or the like is used as an adhesive expecting the action of self alignment is shown, but it is also possible to use an Au-Sn paste as the adhesive 30. . Below, the manufacturing process at the time of using Au-Sn paste as the adhesive agent 30 is demonstrated easily. The Au-Sn paste contains a flux.

  First, a step of stretching the Au-Sn paste to a uniform thickness on a predetermined plane is performed. Next, the adhesion fixing area 24 of the microlens array substrate 20 is brought into contact with the uniformly extended Au-Sn paste, and the Au-Sn paste is uniformly transferred to the adhesion fixing area 24. Next, a heat treatment at 280 ° C. or higher is performed in a nitrogen atmosphere to cure the Au—Sn paste transferred to the adhesion fixing area 24. Next, the flux remaining in the adhesion fixing area 24 is washed with a washing solution.

  Next, the microlens array substrate 20 having the Au-Sn paste transferred to the adhesion fixing area 24 is disposed at a predetermined position of the surface emitting laser array substrate 10 and reheated in a nitrogen atmosphere to prevent Au oxidation to prevent oxidation of Sn. 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 state of being aligned with high accuracy by self alignment. The positional accuracy of the self alignment is the same as in the case of using an Au-Sn vapor deposition film or the like.

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

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

  The restoring force F acts to equalize the contact angle by the surface tension of the wet spread adhesive 30. Specifically, the resilience F can be expressed by the following equation (1).

F = L × γ × cos θ (1)
Here, L is the length of the side on which the adhesive 30 is wet, θ is the contact angle, and γ is the surface tension. As shown in equation (1), the restoring force F received by the microlens array substrate 20 is such that the longer the length L of the side on which the adhesive 30 is wet, the longer the surface tension γ, and the smaller the contact angle θ. It becomes a big value. Therefore, as the shape of the area where the adhesive 30 gets wet (the planar shape of the adhesive fixing areas 14 and 24), it is preferable to have 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 bonding and fixing area is different from that of the first embodiment is shown. In the second embodiment, the description of the same components as those in the embodiments already described may be omitted.

  As described above, the planar shape of the area in which 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 area 14 is square, but in the surface emitting laser array substrate 10A shown in FIG. 9, the planar shape of the adhesive fixing area 14A is rectangular. The adhesion fixing regions 14A disposed at the four corners are a pattern that alternately repeats vertical and horizontal along the outer shape of the semiconductor substrate 11.

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

  From the equation (1), the restoring force F works more in the direction of the long side of the rectangle. Therefore, by the arrangement of the adhesive fixing area 14A as shown in FIG. 9, the restoring force F received from the adhesive 30 adjacent to the microlens array substrate in the self alignment becomes orthogonal. As a result, effective alignment can be performed against 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 bonding and fixing area is different from that of the first embodiment will be shown. In the third embodiment, the description of the same components as those in the embodiments already described may be omitted.

  As described above, the shape of the area in which the adhesive 30 is wetted 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 area 14 is square, and in the second embodiment, the planar shape of the adhesive fixing area 14A is rectangular. On the other hand, in the surface emitting laser array substrate 10B shown in FIG. 10, the planar shape of the adhesion fixing region 14B is L-shaped (a combination of a square and a rectangle). The adhesive fixing areas 14 B arranged at the four corners have a pattern in which the inside of the L-shape is directed to the center side of the semiconductor substrate 11. The L-shaped longitudinal portion and the short portion may have the same length.

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

  By the arrangement of the adhesive fixing area 14B as shown in FIG. 10, the restoring force F received from the adhesive 30 adjacent to the microlens array substrate during self alignment has a component parallel to an orthogonal component. As a result, effective alignment can be performed with respect to rotational displacement of the microlens array substrate with respect to the surface emitting laser array substrate 10B and displacement in the XY directions.

Fourth Embodiment
The fourth embodiment shows an example of a surface emitting laser device in which the shape of the microlens array substrate is different from that of the first embodiment. In the fourth embodiment, the description of the same components as those in the embodiments already described may be omitted.

  FIG. 11 is a view illustrating a microlens array substrate according to the fourth embodiment, and FIG. 11 (a) is a plan view, and FIG. 11 (b) is along the line C-C of FIG. 11 (a). FIG.

  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 the thermal stress resulting from the difference between the thermal expansion coefficients of the two may remain in the semiconductor substrate.

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

  The planar shape of the hinge 25 can be, for example, an L shape. In this case, in each of the hinges 25, in plan view, L-shaped short parts are connected to each corner of the transparent substrate 21, and L-shaped long parts are predetermined with the sides of the transparent substrate 21 connected with the short parts. Can be spaced parallel to one another. The respective hinges 25 can be arranged so as to be rotationally symmetrical in plan view.

  A bridge leg 23 projecting in the Z direction is formed on one end of the L-shaped longitudinal portion of the hinge 25 so as to protrude on one surface 11 a side of the semiconductor substrate 11, and an adhesive fixing area 24 is formed on the bottom surface of the bridge leg 23. It is done. Although not shown, the bonding and fixing area of the surface emitting laser array substrate is also formed in a planar shape corresponding to the bonding and fixing area 24 of the microlens array substrate 20C, and arranged at a position corresponding to the bonding and fixing area 24.

  As described above, by supporting the microlens array substrate 20C with the four hinges 25, it is possible to relieve the thermal stress at the time of bonding, and the surface emitting laser array substrate is configured due to the difference in the thermal expansion coefficient. Stress remaining in 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 the adhesion fixing area of the microlens array substrate is shown. In the fifth embodiment, the description of the same components as those in the embodiments already described may be omitted.

  FIG. 12 is a cross-sectional view illustrating the main part of a surface emitting laser device according to the fifth embodiment. As shown in FIG. 12, in the surface emitting laser device 1D, an adhesive fixing region 24D is provided in place of the adhesive fixing region 24 on the bottom surface of the bridge leg 23 of the microlens array substrate 20. It differs from 1). The adhesion fixing area 24D is provided with an opening 240 penetrating the adhesion fixing area 24D in the thickness direction.

  FIG. 13 is a plan view illustrating the bonding and fixing area 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. Also, as shown in FIG. 13B, the planar shape of the opening 240 may be, for example, a circle or an ellipse. Alternatively, as shown in FIG. 13C, the opening 240 may reach the end, and for example, the adhesion fixing area 24D may have a U-shaped planar shape.

  Alternatively, the plane 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). Also, a plurality of openings 240 may be provided in one adhesive fixing area 24D (for example, two circular openings). At this time, the plurality of openings 240 may have different shapes (for example, a mixture of square openings and circular openings).

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

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

  By the way, in the first embodiment, in the case where the adhesive 30 (solder, Au-Sn, etc.) is locally heated by laser light, the laser light is made to be incident on the adhesive fixing area 24 from the transparent microlens array substrate 20 side. Is considered. However, when laser light is made incident to the adhesive fixing area 24 from the side of the microlens array substrate 20, the reflection is large, and for melting the adhesive 30, more energy is consumed than when laser is made directly incident to the adhesive 30. Expected to be needed.

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

  Therefore, in the present embodiment, in order to melt the adhesive 30 by laser light more efficiently, the adhesive fixing area 24 is substituted for the microlens array substrate 20 so that the laser light is directly incident on the adhesive 30. An adhesive fixing area 24D having an opening 240 is provided.

  By providing the opening 240 in the adhesion fixing area 24D, as shown in FIG. 14A, the laser light La emitted from the heating device is transmitted from the microlens array substrate 20 side to the opening 240 of the adhesion fixing area 24D. And directly enter the adhesive 30. As a result, it is possible to melt the adhesive 30 efficiently. Further, by providing the opening portion 240 in the adhesion fixing area 24D, the length of the interface with the adhesive 30 is increased, and therefore, it can be expected that the surface tension is increased.

  As a result, as shown in FIG. 14B, the surface emitting laser array substrate 10 and the microlens array substrate 20 self-align with each other by the restoring force of the melted adhesive 30, and then the adhesive 30 solidifies. It is fixed in a state of being aligned with higher accuracy.

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

  Although the preferred embodiments have been described above in detail, the present invention is not limited to the above-described embodiments, and various modifications and substitutions may be made to the above-described embodiments 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, but the present invention relates to a surface emitting laser device including the surface emitting laser substrate and the microlens substrate Is also applicable. That is, in the surface emitting laser device according to the present invention, each of the surface emitting laser and the micro lens may be one or plural.

DESCRIPTION OF SYMBOLS 1, 1D surface emitting laser device 10, 10A, 10B surface emitting laser array substrate 11 semiconductor substrate 11a one surface of a semiconductor substrate 11b other surface of a semiconductor substrate 12 surface emitting laser array 13 anode electrode 14, 14A, 14B, 24, 24D adhesive fixing area 20, 20C microlens array substrate 21 transparent substrate 21a opposing surface 22 microlens array 23 bridge 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 Unexamined-Japanese-Patent No. 2002-26452

Claims (10)

A surface emitting laser substrate disposed on a semiconductor substrate and emitting light from one surface side of the semiconductor substrate , and a surface emitting laser substrate including a plurality of first adhesion fixing regions on the one surface.
Formed at a position facing the first adhesive fixing area of the bottom surface of each of the micro-lenses to which the emitted light of the surface-emitting laser is incident, the plurality of bridge portions projecting on one surface side of the semiconductor substrate, and each bridge portion. A microlens substrate comprising a second adhesive fixing area,
An adhesive for bonding the first adhesive fixing area and the second adhesive fixing area;
The first adhesive fixing area is formed of a material which is more easily wettable to the adhesive than the material forming the semiconductor substrate,
The surface-emitting laser device, wherein the second adhesive fixing area is formed of a material which is more easily wettable to the adhesive than the material constituting the bridge leg . The planar shape of the semiconductor substrate is a square,
The plurality of first adhesive fixing areas are disposed at four corners of the semiconductor substrate,
The planar shape of each of the first adhesive fixing areas is a rectangle,
The adjacent first adhesive fixing areas are arranged in a positional relationship in which the long sides are orthogonal to each other,
2. The surface emitting laser device according to claim 1 , wherein each of the second adhesive fixing regions is formed in a planar shape corresponding to the first adhesive fixing region, and is disposed at a position corresponding to the first adhesive fixing region. The planar shape of the semiconductor substrate is a square,
The plurality of first adhesive fixing areas are disposed at four corners of the semiconductor substrate,
The planar shape of each of the first adhesive fixing areas is L-shaped,
Each of the first adhesive fixing regions is arranged such that the inside of the L-shape is directed to the center side of the semiconductor substrate,
2. The surface emitting laser device according to claim 1 , wherein each of the second adhesive fixing regions is formed in a planar shape corresponding to the first adhesive fixing region, and is disposed at a position corresponding to the first adhesive fixing region. The microlens substrate is provided with a plurality of hinges extending in a direction parallel to one surface of the semiconductor substrate from the portion where the microlens is formed.
The surface emitting laser device according to any one of claims 1 to 3 , wherein the bridge portion projecting on one surface side of the semiconductor substrate is formed at one end of each of the hinges. The surface emitting laser according to any one of claims 1 to 4 , wherein a plurality of the surface emitting lasers and the microlenses are respectively formed, and each of the surface emitting lasers and each of the microlenses is disposed at a corresponding position. Laser device. The surface emitting laser device according to any one of claims 1 to 5 , wherein an opening is provided in the second adhesive fixing area. Forming a surface emitting laser for emitting light from one surface side of the semiconductor substrate on the semiconductor substrate ; a material which is more easily wettable by the adhesive than the material constituting the semiconductor substrate on one surface of the semiconductor substrate forming a surface emitting laser substrate comprising the step, of forming a first adhesive fixing area consisting,
A step of forming a micro lens and a plurality of bridge legs on which a light emitted from the surface emitting laser is incident on a transparent substrate, wherein the bridge legs are formed at positions corresponding to the first adhesive fixing area of the bottom surface of each bridge leg ; Forming a second adhesive fixing area made of a material that is more easily wettable to the adhesive than a material ; forming a microlens substrate;
And said first adhesive fixing region the second bonded region and a step of bonding with the adhesive,
The step of adhering is
Placing the adhesive in each of the first adhesive fixing area or in each of the second adhesive fixing area;
Disposing the microlens substrate on the surface emitting laser substrate such that each of the second adhesive fixing regions opposes 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. 8. The method of manufacturing a surface emitting laser device according to claim 7, wherein the first adhesion fixing region is formed using the same mask as that forming the electrode of the surface emitting laser. The method for manufacturing a surface emitting laser device according to claim 7 or 8, wherein the adhesive is melted using a heating device which heats the plurality of the adhesives locally and simultaneously. An opening is provided in the second adhesive fixing area,
The heating device is a device that emits a laser beam,
In the self-aligning step, laser light emitted from the heating device is made to enter the adhesive directly from the side of the microlens substrate, passing through the opening of the second adhesive fixing area, and the adhesive is The method of manufacturing a surface emitting laser device according to claim 9, wherein the method is melted.

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