SURFACE EMITTING LASER DEVICE, ELECTRONIC DEVICE, AND MANUFACTURING METHOD FOR SURFACE EMITTING LASER DEVICE

A main object is to provide a surface emitting laser device capable of suppressing variation in interval between an element unit and a driver unit while suppressing breakage of the element unit. The present technology is a surface emitting laser device (1) including: an element unit (10) including an element arrangement area (EA) in which a plurality of surface emitting laser elements (100) is arranged and an adjacent area (AA) adjacent to the element arrangement area (EA); a driver unit (20) including a driver IC; a plurality of first bumps (BP1) that individually joins each of the plurality of surface emitting laser elements (100) and the driver unit (20); and a plurality of second bumps (BP2) that joins the adjacent area (AA) and the driver unit (20), in which each of the plurality of first bumps (BP1) and the plurality of second bumps (BP2) includes a conductive material that becomes difficult to be crushed by pressurization, and the plurality of second bumps (BP2) is arranged at a higher density than the plurality of first bumps (BP1).

TECHNICAL FIELD

The technology according to the present disclosure (hereinafter also referred to as “the present technology”) relates to a surface emitting laser device, an electronic device, and a manufacturing method for the surface emitting laser device.

BACKGROUND ART

Conventionally, there is known a technique of joining a semiconductor device (for example, a semiconductor chip) having a plurality of semiconductor elements to a board via a member having high mechanical strength (for example, see Patent Document 1).

CITATION LIST

Patent Document

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, in the above-described conventional technique, there has been room for improvement in suppressing variation in interval between the semiconductor device and the board while suppressing breakage of the semiconductor device.

Therefore, a main object of the present technology is to provide a surface emitting laser device capable of suppressing variation in interval between an element unit and a driver unit while suppressing breakage of the element unit.

Solutions to Problems

The present technology provides a surface emitting laser device including:an element unit including an element arrangement area in which a plurality of surface emitting laser elements is arranged and an adjacent area adjacent to the element arrangement area;a driver unit including a driver IC;a plurality of first bumps that individually joins each of the plurality of surface emitting laser elements and the driver unit; anda plurality of second bumps that joins the adjacent area and the driver unit, in whicheach of the plurality of first bumps and the plurality of second bumps contains a conductive material that becomes difficult to be crushed by pressurization, andthe plurality of second bumps is arranged at a higher density than the plurality of first bumps.

Each of the plurality of surface emitting laser elements may have a mesa structure protruding toward the driver unit side and including an electrode at a top, and the electrode and the driver unit may be joined via the first bumps.

The conductive material may be metal particle paste.

The conductive material may be metal nano paste.

The arrangement density of the plurality of second bumps may be higher than the arrangement density of the plurality of surface emitting laser elements.

The adjacent area may include at least first and second areas respectively located on one side and another side sandwiching the element arrangement area.

The element unit may have a multilayer structure including first and second multilayer film reflectors and an active layer disposed between the first and second multilayer film reflectors, the element arrangement area may constitute a part of the multilayer structure in an in-plane direction, and the adjacent area may constitute another part of the multilayer structure in the in-plane direction.

The driver unit may include a semiconductor board on which the driver IC is formed, and a wiring layer layered on the semiconductor board, and the wiring layer may be joined to the plurality of surface emitting laser elements via the plurality of first bumps, and joined to the adjacent area via the plurality of second bumps.

The present technology also provides an electronic device including the surface emitting laser device.

The present technology also provides a manufacturing method for a surface emitting laser device including: an element unit including an element arrangement area in which a plurality of surface emitting laser elements is arranged and an adjacent area adjacent to the element arrangement area; and a driver unit including a driver IC, the manufacturing method including:a joining step of joining each of the plurality of surface emitting laser elements and the driver unit via a plurality of first bumps, and joining the adjacent area and the driver unit via a plurality of second bumps, in whichthe plurality of first bumps and the plurality of second bumps contain a conductive material that becomes difficult to be crushed by pressurization, and in the joining step, the plurality of second bumps is arranged at a higher density than the plurality of first bumps.

The manufacturing method for the surface emitting laser device according to the present technology may further include: prior to the joining step, a step of arranging the plurality of first bumps in an area in the driver unit corresponding to the element arrangement area; and a step of arranging the plurality of second bumps in an area in the driver unit corresponding to the adjacent area at a higher density than the plurality of first bumps.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of the present technology will be described in detail with reference to the accompanying drawings. Note that, in this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations are omitted. The embodiment described below shows one example of a representative embodiment of the present technology, and does not cause the scope of the present technology to be narrowly interpreted. In this specification, even in a case where it is described that each of a surface emitting laser device, an electronic device, and a manufacturing method for the surface emitting laser device according to the present technology exhibits a plurality of effects, it suffices that each of the surface emitting laser device, the electronic device, and the manufacturing method for the surface emitting laser device according to the present technology exhibits at least one effect. The effects described in this specification are merely examples and are not limited, and other effects may also be present.

Furthermore, the description will be given in the following order.

1. Configuration of surface emitting laser device according to one embodiment of present technology

2. Operation of surface emitting laser device according to one embodiment of present technology

3. Manufacturing method for surface emitting laser device according to one embodiment of present technology

4. Effect of surface emitting laser device and effect of manufacturing method thereof according to one embodiment of present technology

5. Modification of one embodiment of present technology

6. Example in which surface emitting laser device is applied to distance measuring device

7. Example in which distance measuring device is mounted on mobile object

<Application Example to Electronic Device>

1. <Configuration of Surface Emitting Laser Device According to One Embodiment of Present Technology>

FIG.1is a plan view of a surface emitting laser device1according to one embodiment of the present technology.FIG.2is a cross-sectional view of the surface emitting laser device1(a cross-sectional view taken along line P-P inFIG.1).

As illustrated inFIGS.1and2, the surface emitting laser device1includes an element unit10and a driver unit20including a driver IC.

The element unit10is disposed on the driver unit20.

As illustrated inFIG.2, the element unit10and the driver unit20are electrically connected via a plurality of bumps BP (BP1, BP2).

More specifically, the surface emitting laser device1further includes a plurality of first bumps BP1that joins each of a plurality of surface emitting laser elements100and the driver unit20, and a plurality of second bumps BP2that joins an adjacent area AA and the driver unit20.

As illustrated inFIG.1, the element unit10includes an element arrangement area EA in which the plurality of surface emitting laser elements100is arranged, and the adjacent area AA adjacent to the element arrangement area EA. The element unit10is a chip-shaped unit as a whole, and is also called a laser chip.

As an example, the adjacent area AA includes first and second adjacent areas AA1and AA2respectively located on one side and another side sandwiching the element arrangement area EA.

In the element arrangement area EA, as illustrated inFIG.2, the plurality of surface emitting laser elements100is two-dimensionally arranged (for example, matrix arrangement, staggered arrangement, random arrangement, or the like) on a board15.

FIG.3is a partially enlarged view extracting and illustrating a part of the element arrangement area inFIG.2(an area surrounded by a one-dot chain line inFIG.2).FIG.4is a partially enlarged view extracting and illustrating a part of the adjacent area inFIG.2(an area surrounded by a two-dot chain line inFIG.2).FIG.5is a partially enlarged view extracting and illustrating an area extending over the element arrangement area and the adjacent area inFIG.2(an area surrounded by a broken line inFIG.2).

The element unit10has a multilayer structure as illustrated inFIGS.3to5.

In the multilayer structure, a first contact layer101, a first multilayer film reflector102, a first spacer layer104, an active layer105, a second spacer layer106, a second multilayer film reflector107, a second contact layer108, and an electrode are layered in this order on the board15.

That is, the multilayer structure includes the first and second multilayer film reflectors102and107, and the active layer105disposed between the first and second multilayer film reflectors102and107.

The element arrangement area EA constitutes a part of the multilayer structure in an in-plane direction (a direction orthogonal to a layering direction), and the adjacent area AA constitutes another part of the multilayer structure in the in-plane direction (a direction orthogonal to the layering direction).

In the element arrangement area EA, each of the plurality of surface emitting laser elements100has a mesa structure MS1protruding toward the driver unit20side and including a cathode electrode110at the top, as illustrated inFIG.3. The cathode electrode110and the driver unit20are joined via the first bumps BP1.

The mesa structure MS1constitutes a part of the multilayer structure in the in-plane direction (however, at least the board15is excluded) in which the cathode electrode110is an uppermost layer (a layer farthest from the board15). The mesa structure MS1functions as a laser resonator of the surface emitting laser element100.

As illustrated inFIG.4, each of the first and second adjacent areas AA1and AA2of the adjacent area AA has a mesa structure MS2protruding toward the driver unit20side and including an electrode111at the top.

The mesa structure MS2constitutes another part of the multilayer structure in the in-plane direction (however, at least the board15is excluded) in which the electrode111is an uppermost layer (a layer farthest from the board15).

Each mesa structure has, for example, a substantially cylindrical shape in plan view, but may have another columnar shape such as a polygonal columnar shape.

The multilayer structure is covered with an insulating film109except for an area where the electrode is disposed. The insulating film109contains, for example, SiO2, SiN, SiON, or the like.

As illustrated inFIG.3, in the insulating film109covering the top of the mesa structure MS1, a contact hole CH1for electrode extraction is formed. In the contact hole CH1, the cathode electrode110is disposed so as to be in contact with the second contact layer108of the mesa structure MS1.

As illustrated inFIG.4, in the insulating film109covering the top of the mesa structure MS2, a contact hole CH2for electrode extraction is formed. In the contact hole CH2, the electrode111is disposed so as to be in contact with the second contact layer108of the mesa structure MS2.

The board15is, as an example, a GaAs board of a first conductivity type. The board15is transparent to an oscillation wavelength of the surface emitting laser element100.

The first contact layer101includes, as an example, a GaAs-based compound semiconductor of the first conductivity type. As illustrated inFIGS.3to5, the first contact layer101is shared by the plurality of surface emitting laser elements100in the element arrangement area EA and the adjacent area AA.

As illustrated inFIG.5, a contact hole CH3for electrode extraction is formed in the insulating film109covering a portion between the mesa structure MS1and the mesa structure MS2adjacent to each other in the multilayer structure. In the contact hole CH3, an anode electrode112is disposed so as to be in contact with the first contact layer101.

The anode electrode112is electrically connected to the electrode111provided at the top of the mesa structure MS2via a coupling layer113.

The coupling layer113is, for example, an Au plating layer.

The anode electrode112may have a single layer structure or a multilayer structure.

In a case where the anode electrode112has a multilayer structure, the anode electrode112contains a material such as, for example, Ti/Au, Ti/Al, Ti/Al/Au, Ti/Pt/Au, Ni/Au, Ni/Au/Pt, Ni/Pt, Pd/Pt, or Ag/Pd.

The first multilayer film reflector102is, as an example, a semiconductor multilayer film reflector. The multilayer film reflector is also referred to as a distributed Bragg reflector. A semiconductor multilayer film reflector which is a type of multilayer film reflector (the distributed Bragg reflector) has low light absorption, high reflectance, and conductivity. The first multilayer film reflector102is also referred to as a lower DBR.

The first multilayer film reflector102is, as an example, a semiconductor multilayer film reflector of the first conductivity type, and has a structure in which a plurality of types (for example, two types) of semiconductor layers (refractive index layers) having different refractive indexes are alternately layered with an optical thickness of ¼ (λ/4) of an oscillation wavelength A. Each refractive index layer of the first multilayer film reflector102includes, for example, an AlGaAs-based compound semiconductor of the first conductivity type.

Inside the first multilayer film reflector102of the mesa structure MS1, a current constriction layer103is disposed (seeFIG.3). As an example, the current constriction layer103includes a non-oxidized area103acontaining AlAs, and an oxidized area103bcontaining an oxide of AlAs (for example, Al2O3) and surrounding the non-oxidized area.

Inside the first multilayer film reflector102of the mesa structure MS2, an oxide constriction layer103′ is disposed (seeFIG.4). The oxide constriction layer103′ has a configuration substantially similar to the current constriction layer103.

The first spacer layer104includes an AlGaAs-based compound semiconductor of the first conductivity type. The “spacer layer” is also referred to as a “clad layer”.

The active layer105has a quantum well structure including a barrier layer including, for example, an AlGaAs-based compound semiconductor, and a quantum well layer. This quantum well structure may be a single quantum well structure (QW structure) or a multiple quantum well structure (MQW structure).

The second spacer layer106(an upper spacer layer) includes an AlGaAs-based compound semiconductor of a second conductivity type. The “spacer layer” is also referred to as a “clad layer”.

The second multilayer film reflector107is, as an example, a semiconductor multilayer film reflector of the second conductivity type, and has a structure in which a plurality of types (for example, two types) of semiconductor layers (refractive index layers) having different refractive indexes are alternately layered with an optical thickness of ¼ wavelength of the oscillation wavelength. Each refractive index layer of the second multilayer film reflector107includes, for example, an AlGaAs-based compound semiconductor of the second conductivity type.

The second contact layer108of each of the surface emitting laser elements100includes, for example, a GaAs-based compound semiconductor of the second conductivity type.

The cathode electrode110of each of the surface emitting laser elements100may have a single layer structure or a multilayer structure.

The cathode electrode110is joined to the driver unit20via the first bump BP1.

In a case where the cathode electrode110has a multilayer structure, the cathode electrode110contains a material such as, for example, Ti/Au, Ti/Al, Ti/Al/Au, Ti/Pt/Au, Ni/Au, Ni/Au/Pt, Ni/Pt, Pd/Pt, or Ag/Pd.

The electrode111may have a single layer structure or a multilayer structure.

As illustrated inFIG.4, the electrode111is joined to the driver unit20via a plurality of second bumps BP2.

In a case where the electrode111has a multilayer structure, the electrode111contains a material such as, for example, Ti/Au, Ti/Al, Ti/Al/Au, Ti/Pt/Au, Ni/Au, Ni/Au/Pt, Ni/Pt, Pd/Pt, or Ag/Pd.

The driver unit20controls the plurality of surface emitting laser elements100of the element unit10. The driver unit20causes at least some of the plurality of surface emitting laser elements100to emit light by independently driving the plurality of surface emitting laser elements100. The driver unit20drives, for example, at least some of the surface emitting laser elements100selected by a system controller30to be described later among the plurality of surface emitting laser elements100.

As illustrated inFIG.2, the driver unit20includes a semiconductor board21(for example, Si board) on which a driver IC is formed, and a wiring layer22layered on the semiconductor board21.

As an example, the driver IC includes an NMOS driver that controls a voltage applied to the element unit10. This NMOS driver generates a drive pulse for performing light emission/extinction of the plurality of surface emitting laser elements100of the element unit10. This NMOS driver is electrically connected to the element unit10via the wiring layer22.

The wiring layer22is joined to the plurality of surface emitting laser elements100via the plurality of first bumps BP1, and joined to the adjacent area AA via the plurality of second bumps BP2.

The wiring layer22includes, for example, a plurality of metal layers22aand a plurality of connection pads22din an insulating layer22b.

The plurality of metal layers22aelectrically connects the NMOS driver in the semiconductor board21and the plurality of connection pads22d.

The plurality of connection pads22dis arranged at positions facing the element unit10in the wiring layer22, is electrically connected to the element arrangement area EA via the plurality of first bumps BP1, and is electrically connected to the adjacent area AA via the plurality of second bumps BP2.

A plurality of connection pads22cis disposed at positions not facing the element unit10in the wiring layer22, and is electrically connected to, for example, a bonding wire44described later. Note that an electrical connection mode between the element unit10and the driver unit20is not limited to that illustrated inFIG.2.

The plurality of first bumps BP1and the plurality of second bumps BP2include a conductive material that can be shifted from a softened state (a relatively soft state) to a cured state (a relatively hard state) at a time of joining.

The conductive material is preferably a conductive material that becomes difficult to be crushed by pressurization.

Specifically, the conductive material may be, for example, metal particle paste. The metal particle paste can be gradually shifted from the softened state to the cured state by pressurization. Moreover, the metal paste can be solidified by sintering. Examples of the metal particle paste include Au particle paste, Ag particle paste, Cu particle paste, and the like.

The metal particle paste is preferably metal nano paste containing metal nanoparticles. In the metal nano paste, metal particles containing metal nanoparticles having a particle size of less than 1 μm are dispersed in a resin binder. Examples of the metal nano paste include Au nano paste, Ag nano paste, Cu nano paste, and the like.

The conductive material may be, for example, alloy paste. The alloy paste may be, for example, solder paste (cream solder). The solder paste has a property (thixotropy) in which a viscosity decreases (becomes the softened state) when stirred, and the viscosity returns to the original state (the cured state) when left to stand. Specific examples of the solder paste include Sn—Ag-based solder paste, Sn—Au-based solder paste, Sn—Cu-based solder paste, and the like.

The plurality of second bumps BP2is arranged at a higher density than the plurality of first bumps BP1.

That is, an amount (an area density) per unit area of the plurality of second bumps BP2is larger than that of the plurality of first bumps BP1.

For example, in a case where a size of the second bump BP2is smaller than a size of the first bump BP1, an interval between the adjacent second bumps BP2is preferably an interval less than an interval between the adjacent first bumps BP1, in which an area density of the plurality of second bumps BP2is preferably higher than an area density of the plurality of first bumps BP1.

For example, in a case where the size of the second bump BP2is equal to or larger than the size of the first bump BP1, the interval between the adjacent second bumps BP2may be less than the interval between the adjacent first bumps BP1.

For example, in a case where the size of the second bump BP2is equal to or larger than the size of the first bump BP1, the interval between the adjacent second bumps BP2may be an interval equal to or more than the interval between the adjacent second bumps BP1, in which the area density of the plurality of second bumps BP2may be higher than the area density of the plurality of first bumps BP1.

Here, as an example, as illustrated inFIG.2, the sizes of the first and second bumps BP1and BP2are the same, and the interval between the adjacent second bumps BP2is less than the interval between the adjacent first bumps BP1.

An arrangement density of the plurality of second bumps BP2is preferably higher than an arrangement density of the plurality of surface emitting laser elements100.

That is, an amount (an area density) per unit area of the plurality of second bumps BP2is preferably larger than that of the plurality of surface emitting laser elements100.

FIG.6is a plan view illustrating an example in which the driver unit20of the surface emitting laser device1is mounted on a printed wiring board40. The printed wiring board40is provided with, for example, the system controller30in addition to the surface emitting laser device1.

FIG.7is a cross-sectional view taken along line Q-Q inFIG.6. Between the driver unit20and the printed wiring board40, a joining layer43is provided. The joining layer43fixes the driver unit20and the printed wiring board40to each other. The joining layer43includes, for example, an insulating resin material.

The driver unit20and the printed wiring board40are electrically connected by the bonding wire44. One end of the bonding wire44is fixed to the connection pad22cof the driver unit20by solder25, and another end of the bonding wire44is fixed to the connection pad41of the printed wiring board40by solder42.

2. <Operation of Surface Emitting Laser Device According to One Embodiment of Present Technology>

In the surface emitting laser device1, a current is supplied from the printed wiring board40to the driver IC formed on the semiconductor board21of the driver unit20, via the bonding wire44and the wiring layer22of the driver unit20. As a result, the driver IC operates, and a current is injected into the anode electrode112via the wiring layer22, the plurality of second bumps BP2, the adjacent area AA, and the coupling layer113. The current injected into the anode electrode112is supplied to the mesa structure MS1of the surface emitting laser element100as a light-emitting target, via the first contact layer101. The current supplied to the mesa structure MS1is injected into the active layer105via the first multilayer film reflector102, the current constriction layer103, and the first spacer layer104of the mesa structure MS1. As a result, when the active layer105emits light, the light is amplified while being repeatedly reflected between the first and second multilayer film reflectors102and107, and an oscillation condition is satisfied, the light is emitted from the board15as laser light.

3. <Manufacturing Method for Surface Emitting Laser Device According to One Embodiment of Present Technology>

Hereinafter, a manufacturing method for a surface emitting laser device1according to one embodiment will be described with reference toFIGS.8to32.FIG.8is a flowchart for explaining a manufacturing method for the surface emitting laser device1.

In the first step S1, element unit generation processing is performed. Details of the element unit forming step will be described later.

In the next step S2, driver unit generation processing is performed. Note that, in a case where an existing driver unit20can be prepared, step S2(the driver unit generation processing) may be omitted.

In the next step S3, bump forming processing is performed. Details of the bump forming processing will be described later.

In the final step S4, joining processing is performed. Details of the joining processing will be described later.

Hereinafter, the element unit generation processing (step S1inFIG.8) will be described with reference to a flowchart inFIG.9and cross-sectional views inFIGS.10to20.

Here, as an example, a plurality of element units10is simultaneously generated on one wafer which is a base material of the board15, by a semiconductor manufacturing method. Next, the plurality of element units10integrated in series is separated from each other by dicing to obtain a plurality of element units10for each unit (for each chip).

In the first step S11, a multilayer body L is generated. Specifically, by using a chemical vapor deposition (CVD) method, for example, a metal organic chemical vapor deposition (MOCVD) method, the multilayer body L is generated by layering the first contact layer101, the first multilayer film reflector102, the first spacer layer104, the active layer105, the second spacer layer106, the second multilayer film reflector107internally including a selectively oxidized layer103S, and the second contact layer108in this order on the board15(seeFIG.10).

In the next step S12, a mesa is formed.

Specifically, the multilayer body L is etched to form a mesa (seeFIGS.11and12).

More specifically, first, a resist pattern for forming mesas to be the mesa structures MS1and MS2is generated on the second contact layer108of the multilayer body L. Next, the mesa is formed by etching (for example, wet etching using a sulfuric acid-based etchant) on the multilayer body L by using this resist pattern as a mask. Here, etching is performed until the first contact layer101is exposed. Thereafter, the resist pattern is removed.

In the next step S13, the current constriction layer103is formed.

Specifically, the current constriction layer103is generated by oxidizing a peripheral portion of the selectively oxidized layer103S of the mesa (seeFIG.13). At this time, the oxide constriction layer103′ is also formed at the same time.

Specifically, by exposing the mesa to a water vapor atmosphere to oxidize (selectively oxidize) the selectively oxidized layer103S from a side surface, the current constriction layer103and the oxide constriction layer103′ are formed in which a non-oxidized area is surrounded by an oxidized area.

In the next step S14, the insulating film109is formed.

Specifically, the insulating film109is formed on the multilayer body in which the mesa is formed (seeFIGS.15and16).

In the next step S15, an electrode is formed.

Specifically, first, the insulating film109is formed, and a resist pattern for forming the cathode electrode110, the electrode111, and the anode electrode112is generated on the multilayer body in which the mesa is formed. Next, using this resist pattern as a mask, the insulating film109at a portion where the cathode electrode110, the electrode111, and the anode electrode112are to be provided is removed by etching (for example, etching using a hydrofluoric acid-based etchant) (seeFIGS.17and18). Next, for example, an Au/Ti film is formed on the multilayer body with the etched insulating film109by, for example, an EB vapor deposition method, and the cathode electrode110, the electrode111, and the anode electrode112are formed by lifting off the resist and, for example, Au/Ti on the resist (seeFIG.19andFIG.20A).

In the next step S16, the coupling layer113is formed.

Specifically, for example, the coupling layer113that connects the electrode111and the anode electrode112is formed using a plating method (seeFIG.20B).

Note that, before the plating method is used, a backing layer to be a plating seed is formed at a portion of the insulating film109where the coupling layer113is to be formed, for example, by vapor deposition, sputtering, or the like. A thickness of the coupling layer113is a thickness (for example, about 2 μm) that can sufficiently prevent a voltage drop.

Thereafter, processing such as annealing, thinning by polishing a back surface of the wafer, and non-reflection coating on the back surface of the wafer is performed, and a plurality of element units10is formed on one wafer. Thereafter, the plurality of element units10is separated for each unit (for each chip) by dicing.

Hereinafter, the bump forming processing (step S3inFIG.8) will be described with reference to a flowchart inFIG.21and a cross-sectional view inFIG.22.

In the first step S31, a plurality of first bumps BP1is formed in an area in the driver unit20corresponding to the element arrangement area EA (seeFIG.22).

Specifically, the first bump BP1in the softened state is attached to a portion of the driver unit20that is to be joined to each of the surface emitting laser elements100of the element unit10.

Note that, for example, in a case where the first bump BP1is solder paste, the solder paste is stirred in advance in the cured state to be in the softened state.

In final step S32, a plurality of second bumps BP2is formed in an area in the driver unit20corresponding to the adjacent area AA (seeFIG.22).

Specifically, the plurality of second bumps BP2in the softened state is attached to a portion that is to be joined to the first adjacent area AA1of the adjacent area AA of the element unit10and a portion that is to be joined to the second adjacent area AA2in the driver unit20.

At this time, the plurality of second bumps BP2is arranged at a higher density than the plurality of first bumps BP1(preferably, a higher density than an arrangement density of the plurality of surface emitting laser elements100).

Note that, for example, in a case where the second bump BP2is solder paste, the solder paste is stirred in advance in the cured state to be in the softened state.

The order of steps S31and S32described above may be reversed.

Hereinafter, the joining processing (step S4inFIG.8) will be described with reference to a flowchart inFIG.23and cross-sectional views inFIGS.24to32.

In first step S41, the element unit10and the driver unit20are disposed to face each other (seeFIG.24).

Specifically, the element units10and the driver unit20are disposed to face each other (seeFIGS.25and26) such that the element arrangement area EA of the element unit10faces an area where the plurality of first bumps BP1in the softened state is formed in the driver unit20, and the adjacent area AA of the element unit10faces an area where the plurality of second bumps BP2in the softened state is formed in the driver unit20.

More specifically, for example, while a manipulator is suctioning and holding the element units10, with respect to the driver unit20placed on a base, the element units10and the driver unit20are disposed to face each other such that each of the surface emitting laser elements100faces the corresponding first bump BP1in the softened state (seeFIG.25), the first adjacent area AA1faces the plurality of corresponding second bumps BP2in the softened state (seeFIG.26), and the second adjacent area AA2faces the plurality of corresponding second bumps BP2in the softened state.

In the next step S42, joining is started between the element unit10and the driver unit20via the plurality of first and second bumps BP1and BP2in the softened state (seeFIG.27).

Specifically, under a predetermined temperature condition, the element unit10suctioned and held by the manipulator is uniformly pressed (pressurized) against the plurality of first and second bumps BP1and BP2in the softened state formed in the driver unit20placed on the base, at a predetermined pressure (seeFIGS.27to29). At this time, the plurality of first bumps BP1and the plurality of second bumps BP2are crushed. The plurality of first bumps BP1and the plurality of second bumps BP2gradually shift to the cured state in the process of being crushed.

In the final step S43, the plurality of first and second bumps BP1and BP2is solidified (seeFIGS.30to32).

Specifically, for example, in a case where the plurality of first and second bumps BP1and BP2is metal particle paste, the first and second bumps BP1and BP2may be heated while being pressurized to be sintered and solidified, or may be sintered in a heating furnace to be solidified (by reflow).

For example, in a case where the plurality of first and second bumps BP1and BP2is solder paste, the solder paste is solidified by being left for a predetermined time after an end of stirring.

4. <Effect of Surface Emitting Laser Device and Manufacturing Method Thereof According to One Embodiment of Present Technology>

Hereinafter, effects of a surface emitting laser device and a manufacturing method thereof according to one embodiment of the present technology will be described.

The surface emitting laser device1according to one embodiment includes: the element unit10including the element arrangement area EA in which a plurality of surface emitting laser elements100is arranged and the adjacent area AA adjacent to the element arrangement area EA; the driver unit20including a driver IC; a plurality of first bumps BP1that joins each of the plurality of surface emitting laser elements100and the driver unit20; and a plurality of second bumps BP2that joins the adjacent area AA and the driver unit20. Each of the plurality of first bumps BP1and the plurality of second bumps BP2contains a conductive material that becomes difficult to be crushed by pressurization, and the plurality of second bumps BP is arranged at a higher density than the plurality of first bumps BP1.

In this case, since the first and second bumps BP1and BP2are relatively soft and stress is dispersed at a time of joining of the element unit10and the driver unit20, breakage of the element unit10can be suppressed. After the element unit10and the driver unit20are joined, the first and second bumps BP1and BP2become relatively hard, so that sufficient joining strength (joining rigidity) can be obtained.

Moreover, since the second bumps BP are arranged at a higher density than the first bumps BP1, it is possible to suppress variation in interval between the element unit10and the driver unit20(more specifically, an interval between opposing positions) as a whole, as compared with a case where the second bumps BP2are arranged at the same density as the first bumps BP1or at a lower density than the first bumps BP1.

As described above, according to the surface emitting laser device1of one embodiment, it is possible to provide the surface emitting laser device capable of suppressing variation in interval between the element unit and the driver unit while suppressing breakage of the element unit. Note that, by suppressing the variation in interval between the element unit and the driver unit, variation in electric resistance between the units can be suppressed.

As a result, according to the surface emitting laser device1, it is possible to realize a surface emitting laser device that can suppress variation in electrical resistance between the units and can be manufactured at a high yield.

As can be seen from the above description, the configuration of the surface emitting laser device1becomes more effective as a mechanical strength of the element unit10is lower.

Each of the plurality of surface emitting laser elements100has the mesa structure MS1protruding toward the driver unit20side and including the cathode electrode110at a top, and the cathode electrode110and the driver unit20are joined via the first bumps BP1. As a result, the cathode electrode110of each of the surface emitting laser elements100and the driver unit20can be easily and reliably electrically connected.

The conductive material is preferably metal particle paste. As a result, it is possible to ensure curability by pressurization.

The conductive material is preferably metal nano paste. As a result, it is possible to sufficiently secure curability by pressurization.

An arrangement density of the plurality of second bumps BP2is preferably higher than an arrangement density of the plurality of surface emitting laser elements100. As a result, it is possible to effectively suppress variation in interval between the element unit10and the driver unit20.

The adjacent area AA includes at least the first and second adjacent areas AA1and AA2respectively located on one side and another side sandwiching the element arrangement area EA. As a result, the arrangement density of the second bumps BP2on both sides sandwiching the element arrangement area EA is high, so that a relative inclination after the element unit10and the driver unit20are joined can be sufficiently suppressed, and variation in interval between the element unit10and the driver unit20can be sufficiently suppressed.

The element unit10has a multilayer structure including the first and second multilayer film reflectors102and107and the active layer105disposed between the first and second multilayer film reflectors102and107, the element arrangement area EA constitutes a part of the multilayer structure in an in-plane direction, and the adjacent area AA constitutes another part of the multilayer structure in the in-plane direction. As a result, the element arrangement area EA and the adjacent area AA can be formed in parallel in a semiconductor manufacturing step.

The driver unit20includes the semiconductor board21on which the driver IC is formed, and the wiring layer22layered on the semiconductor board21, and the wiring layer22is joined to the plurality of surface emitting laser elements100via the plurality of first bumps BP1, and joined to the adjacent area AA via the plurality of second bumps BP2. As a result, it is possible to stably conduct the plurality of surface emitting laser elements100and the driver IC.

A manufacturing method for the surface emitting laser device1according to one embodiment is a manufacturing method for a surface emitting laser device including: an element unit including an element arrangement area in which a plurality of surface emitting laser elements100is arranged and an adjacent area adjacent to the element arrangement area; and a driver unit including a driver IC, and the manufacturing method includes: a joining step of joining each of the plurality of surface emitting laser elements100and the driver unit20via a plurality of first bumps BP1, and joining the adjacent area AA and the driver unit20via a plurality of second bumps BP2. The plurality of first bumps BP1and the plurality of second bumps BP2include a conductive material that becomes difficult to be crushed by pressurization, and the plurality of second bumps BP2is arranged at a higher density than the plurality of first bumps BP1in the joining step.

In this case, since the first and second bumps BP1and BP2are relatively soft and stress is dispersed at a time of joining of the element unit10and the driver unit20, breakage of the element unit10can be suppressed. After the element unit10and the driver unit20are joined, the first and second bumps BP1and BP2become relatively hard, so that sufficient joining strength can be obtained.

Moreover, since the second bumps BP are arranged at a higher density than the first bumps BP1, it is possible to suppress variation in interval between the element unit10and the driver unit20(more specifically, an interval between opposing positions) as a whole, as compared with a case where the second bumps BP2are arranged at the same density as the first bumps BP1or at a lower density than the first bumps BP1.

According to the manufacturing method for the surface emitting laser device1according to one embodiment, it is possible to provide the surface emitting laser device capable of suppressing variation in interval between the element unit and the driver unit while suppressing breakage of the element unit. Note that, by suppressing the variation in interval between the element unit and the driver unit, variation in electric resistance between the units can be suppressed.

As a result, according to the manufacturing method for the surface emitting laser device1, it is possible to manufacture a surface emitting laser element capable of suppressing variation in electric resistance between the units at a high yield.

As can be seen from the above description, the manufacturing method for the surface emitting laser device1becomes more effective as a mechanical strength of the element unit10is lower.

The manufacturing method for the surface emitting laser device1further includes: prior to the joining step, a step of arranging the plurality of first bumps BP1in an area in the driver unit20corresponding to the element arrangement area EA; and a step of arranging the plurality of second bumps BP2in an area in the driver unit20corresponding to the adjacent area AA at a density higher than an arrangement density of the plurality of first bumps BP1. As a result, the element unit10and the driver unit20can be easily joined to each other.

5. <Modification of One Embodiment of Present Technology>

The present technology is not limited to the embodiment described above, and various modifications can be made.

For example, as in a surface emitting laser device1′ of a modification illustrated inFIG.33, in an element unit10′, an adjacent area AA′ may surround four sides of the element arrangement area EA.

Specifically, for example, the adjacent area AA′ may include first and second adjacent areas AA1and AA2respectively disposed at positions on one side and another side sandwiching the element arrangement area EA in a first direction, and third and fourth adjacent areas AA3and AA4respectively disposed at positions on one side and another side sandwiching the element arrangement area EA in a second direction orthogonal to the first direction.

InFIG.33, a cross-sectional view taken along line R-R of the third and fourth adjacent areas AA3and AA4and the element arrangement area EA is substantially similar to the cross-sectional view taken along line P-P (seeFIG.2).

According to the surface emitting laser device1′, since the adjacent area AA′ surrounding the entire periphery of the element arrangement area EA is joined to the driver unit20via the plurality of second bumps BP2, it is possible to more reliably suppress variation in interval between the element unit10′ and the driver unit20.

In the bump forming processing described above, the first bump BP1in the softened state may be formed in each surface emitting laser element of the element unit, and the plurality of second bumps BP2in the softened state may be formed in the adjacent area of the element unit.

In the above-described embodiment and modification, both the first and second multilayer film reflectors102and107are semiconductor multilayer film reflectors, but are not limited thereto.

For example, the first multilayer film reflector102may be a semiconductor multilayer film reflector, and the second multilayer film reflector107may be a dielectric multilayer film reflector. The dielectric multilayer film reflector is also a kind of distributed Bragg reflector.

For example, the first multilayer film reflector102may be a dielectric multilayer film reflector, and the second multilayer film reflector107may be a semiconductor multilayer film reflector.

For example, both the first and second multilayer film reflectors102and107may be dielectric multilayer film reflectors.

In the surface emitting laser device according to the present technology, the first and second spacer layers104and106are not necessarily provided.

In the surface emitting laser device according to the present technology, the current constriction layer103and the oxide constriction layer103′ may be disposed inside the second multilayer film reflector107.

In the surface emitting laser device according to the present technology, the current constriction layer103and the oxide constriction layer103′ are not necessarily provided.

In the surface emitting laser device according to the present technology, at least one of the first and second contact layers101and108is not necessarily provided.

6. <Example in which Surface Emitting Laser Device is Applied to Distance Measuring Device>

Hereinafter, an application example of the surface emitting laser device according to the above-described embodiment and modification will be described.

FIG.34illustrates an example of a schematic configuration of a distance measuring device1000including the surface emitting laser device1, as an example of an electronic device according to the present technology. The distance measuring device1000measures a distance to a subject200by a time of flight (TOF) method. The distance measuring device1000includes the surface emitting laser device1as a light source. The distance measuring device1000includes, for example, the surface emitting laser device1, a light receiving device120, lenses115and130, a signal processing unit140, a control unit150, a display unit160, and a storage unit170.

The light receiving device120detects light reflected by the subject200. The lens115is a lens for collimating light emitted from the surface emitting laser device1, and is a collimating lens. The lens130is a lens for condensing light reflected by the subject200and guiding the light to the light receiving device120, and is a condenser lens.

The signal processing unit140is a circuit for generating a signal corresponding to a difference between a signal inputted from the light receiving device120and a reference signal inputted from the control unit150. The control unit150includes, for example, a time-to-digital converter (TDC). The reference signal may be a signal inputted from the control unit150, or may be an output signal of a detection unit that directly detects an output of the surface emitting laser device1. The control unit150is, for example, a processor that controls the surface emitting laser device1, the light receiving device120, the signal processing unit140, the display unit160, and the storage unit170. The control unit150is a circuit that measures a distance to the subject200on the basis of a signal generated by the signal processing unit140. The control unit150generates a video signal for displaying information about a distance to the subject200, and outputs the video signal to the display unit160. The display unit160displays information about the distance to the subject200, on the basis of the video signal inputted from the control unit150. The control unit150stores information about the distance to the subject200in the storage unit170.

In the present application example, the surface emitting laser device1or the surface emitting laser device1′ is applied to the distance measuring device1000.

7. <Example in which Distance Measuring Device is Mounted on Mobile Object>

The technology (the present technology) according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device equipped on any type of mobile bodies, such as an automobile, an electric car, a hybrid electric car, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, and the like.

FIG.35is a block diagram illustrating a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure may be applied.

A vehicle control system12000includes a plurality of electronic control units connected to each other via a communication network12001. In the example illustrated inFIG.35, the vehicle control system12000includes a driving system control unit12010, a body system control unit12020, a vehicle external information detection unit12030, a vehicle internal information detection unit12040, and an integrated control unit12050. Furthermore, as a functional configuration of the integrated control unit12050, a microcomputer12051, a sound/image output unit12052, and a vehicle-mounted network interface (I/F)12053are illustrated.

The body system control unit12020controls the operation of various kinds of devices provided to a vehicle body in accordance with various kinds of programs. For example, the body system control unit12020functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as a headlamp, a back lamp, a brake lamp, a turn indicator, or a fog lamp. In this case, the body system control unit12020may be inputted with radio waves or signals of various switches transmitted from a portable device that substitutes for a key. The body system control unit12020receives these input radio waves or signals, and controls a door lock device, the power window device, the lamps, or the like of the vehicle.

The vehicle external information detection unit12030detects information about the outside of the vehicle including the vehicle control system12000. For example, a distance measuring device12031is connected to the vehicle external information detection unit12030. The distance measuring device12031includes the above-described distance measuring device1000. The vehicle external information detection unit12030causes the distance measuring device12031to measure a distance to an object (the subject200) outside the vehicle, and acquires distance data obtained by the measurement. The vehicle external information detection unit12030may perform object detection processing of a person, a vehicle, an obstacle, a sign, or the like on the basis of the acquired distance data.

The vehicle internal information detection unit12040detects information about the inside of the vehicle. The vehicle internal information detection unit12040is connected with, for example, a driver state detection unit12041that detects a state of a driver. The driver state detection unit12041, for example, includes a camera that images the driver. On the basis of detection information inputted from the driver state detection unit12041, the vehicle internal information detection unit12040may calculate a degree of fatigue of the driver or a degree of concentration of the driver, or may determine whether the driver is dozing.

Furthermore, the microcomputer12051can perform cooperative control intended for automated driving, which makes the vehicle to travel automatedly without depending on the operation of the driver, or the like, by controlling the driving force generating device, the steering mechanism, the braking device, or the like on the basis of the information about the outside or inside of the vehicle which information is obtained by the vehicle external information detection unit12030or the vehicle internal information detection unit12040.

Furthermore, the microcomputer12051can output a control command to the body system control unit12020on the basis of information about the outside of the vehicle acquired by the vehicle external information detection unit12030. For example, the microcomputer12051can perform cooperative control intended to prevent a glare by controlling the headlamp so as to change from a high beam to a low beam, for example, in accordance with the position of a preceding vehicle or an oncoming vehicle detected by the vehicle external information detection unit12030.

The sound/image output unit12052transmits an output signal of at least one of a sound and an image to an output device capable of visually or auditorily notifying information to an occupant of the vehicle or the outside of the vehicle. In the example ofFIG.35, an audio speaker12061, a display unit12062, and an instrument panel12063are illustrated as the output device. The display unit12062may, for example, include at least one of an on-board display and a head-up display.FIG.36is a view illustrating an example of an installation position of the distance measuring device12031.

InFIG.36, a vehicle12100includes distance measuring devices12101,12102,12103,12104, and12105as the distance measuring device12031.

The distance measuring devices12101,12102,12103,12104, and12105are provided at positions such as, for example, a front nose, side mirrors, a rear bumper, a back door, and an upper part of a windshield in a vehicle cabin, of the vehicle12100. The distance measuring device12101provided at the front nose and the distance measuring device12105provided at the upper part of the windshield in the vehicle cabin mainly acquire data of a front side of the vehicle12100. The distance measuring devices12102and12103provided at the side mirrors mainly acquire data of a side of the vehicle12100. The distance measuring device12104provided at the rear bumper or the back door mainly acquires data of a rear side of the vehicle12100. The data of the front side acquired by the distance measuring devices12101and12105is mainly used for detecting a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, or the like.

Note thatFIG.36illustrates an example of detection ranges of the distance measuring devices12101to12104. A detection range12111indicates a detection range of the distance measuring device12101provided at the front nose, detection ranges12112and12113individually indicate detection ranges of the distance measuring devices12102and12103provided at the side mirrors, and a detection range12114indicates a detection range of the distance measuring device12104provided at the rear bumper or the back door.

For example, the microcomputer12051can determine a distance to each three-dimensional object within the detection ranges12111to12114and a temporal change in the distance (a relative speed with respect to the vehicle12100) on the basis of the distance data obtained from the distance measuring devices12101to12104, and thereby extract, as a preceding vehicle, a nearest three-dimensional object in particular that is present on a traveling path of the vehicle12100and which travels in substantially the same direction as the vehicle12100at a predetermined speed (for example, equal to or more than 0 km/hour). Moreover, the microcomputer12051can set an inter-vehicle interval to be secured from a preceding vehicle in advance, and perform automatic brake control (including follow-up stop control), automatic acceleration control (including follow-up start control), and the like. It is thus possible to perform cooperative control intended for automated driving that makes the vehicle travel automatedly without depending on the operation of the driver or the like.

An example of the mobile object control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the distance measuring device12031among the configurations described above.

The surface emitting laser device according to the present technology may be realized as a light source of a device (for example, a laser printer, a laser copier, a projector, a head-mounted display, a head-up display, or the like) that forms or displays an image by laser light.

In the above-described embodiment and modification, the described specific numerical values, shapes, materials (including compositions), and the like are merely examples, and are not limited thereto.

Furthermore, the present technology can also have the following configurations.

(1) A surface emitting laser device including:an element unit including an element arrangement area in which a plurality of surface emitting laser elements is arranged and an adjacent area adjacent to the element arrangement area;a driver unit including a driver IC;a plurality of first bumps that individually joins each of the plurality of surface emitting laser elements and the driver unit; anda plurality of second bumps that joins the adjacent area and the driver unit, in whicheach of the plurality of first bumps and the plurality of second bumps contains a conductive material that becomes difficult to be crushed by pressurization, andthe plurality of second bumps is arranged at a higher density than the plurality of first bumps.

(2) The surface emitting laser device according to (1), in which each of the plurality of surface emitting laser elements has a mesa structure protruding toward the driver unit side and including an electrode at a top, and the electrode and the driver unit are joined via each of the first bumps.

(3) The surface emitting laser device according to (1) or (2), in which the conductive material is metal particle paste.

(4) The surface emitting laser device according to any one of (1) to (3), in which the conductive material is metal nano

(5) The surface emitting laser device according to any one of (1) to (4), in which an arrangement density of the plurality of second bumps is higher than an arrangement density of the plurality of surface emitting laser elements.

(6) The surface emitting laser device according to any one of (1) to (5), in which the adjacent area includes at least first and second areas respectively located on one side and another side sandwiching the element arrangement area.

(7) The surface emitting laser device according to any one of (1) to (6), in which the element unit has a multilayer structure including first and second multilayer film reflectors and an active layer disposed between the first and second multilayer film reflectors, the element arrangement area constitutes a part of the multilayer structure in an in-plane direction, and the adjacent area constitutes another part of the multilayer structure in the in-plane direction.

(8) The surface emitting laser device according to any one of (1) to (7), in which the driver unit includes a semiconductor board on which the driver IC is formed, and a wiring layer layered on the semiconductor board, and the wiring layer is joined to the plurality of surface emitting laser elements via the plurality of first bumps, and joined to the adjacent area via the plurality of second bumps.

(9) An electronic device including the surface emitting laser device according to any one of (1) to (8).

(10) A manufacturing method for a surface emitting laser device including: an element unit including an element arrangement area in which a plurality of surface emitting laser elements is arranged and an adjacent area adjacent to the element arrangement area; and a driver unit including a driver IC, the manufacturing method including:a joining step of joining each of the plurality of surface emitting laser elements and the driver unit via a plurality of first bumps, and joining the adjacent area and the driver unit via a plurality of second bumps, in whichthe plurality of first bumps and the plurality of second bumps contain a conductive material that becomes difficult to be crushed by pressurization, andin the joining step, the plurality of second bumps is arranged at a higher density than the plurality of first bumps.

(11) The manufacturing method for the surface emitting laser device according to (10), further including: prior to the joining step, a step of arranging the plurality of first bumps in which the conductive material is in a softened state in an area in the driver unit corresponding to the element arrangement area; and a step of arranging the plurality of second bumps in which the conductive material is in a softened state in an area in the driver unit corresponding to the adjacent area at a higher density than the plurality of first bumps.

REFERENCE SIGNS LIST