Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
  • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/26—Optical coupling means
  • G02B6/32—Optical coupling means having lens focusing means positioned between opposed fibre ends
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
  • G02B6/24—Coupling light guides
  • G02B6/42—Coupling light guides with opto-electronic elements
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/02—Structural details or components not essential to laser action
  • H01S5/022—Mountings; Housings
  • H01S5/0225—Out-coupling of light
  • H01S5/02251—Out-coupling of light using optical fibres

Definitions

• This disclosure relates to optical waveguide packages and light source modules.
• a light source module such as that described in Patent Document 1 is known.
• the optical waveguide package of the present disclosure includes a substrate having a first surface; a clad located on the first surface, the clad having a second surface facing the first surface, a third surface located on the opposite side of the second surface, and a through hole extending from the third surface to the second surface; a core located within the cladding, the core having an entrance surface exposed to an inner circumferential surface of the through hole and an exit surface exposed to an end surface of the cladding, the first surface has a first region exposed from the through hole and a second region covered with the cladding, The first region includes an element mounting region, and a surface roughness of the element mounting region is greater than a surface roughness of the second region.
• the light source module of the present disclosure includes the optical waveguide package described above, A light emitting element mounted on the element mounting area; and a lid that closes the opening of the through hole.
• FIG. 2 is an exploded perspective view showing an example of a light source module according to the first embodiment of the present disclosure.
• FIG. 1 is a plan view illustrating an example of an optical waveguide package according to a first embodiment of the present disclosure.
• FIG. 3 is an enlarged plan view showing a part of FIG. 2 .
• 4 is a cross-sectional view taken along the line IV-IV in FIG. 2.
• FIG. 5 is an enlarged cross-sectional view showing a part of FIG. 4 .
• FIG. 4 is an enlarged plan view showing another example of the optical waveguide package according to the first embodiment of the present disclosure.
• 6B is a cross-sectional view taken along the line VIB-VIB in FIG.
• 1A to 1C are diagrams illustrating a manufacturing process of the light source module.
• 1A to 1C are diagrams illustrating a manufacturing process of the light source module.
• 1A to 1C are diagrams illustrating a manufacturing process of the light source module.
• 1A to 1C are diagrams illustrating a manufacturing process of the light source module.
• 1A to 1C are diagrams illustrating a manufacturing process of the light source module.
• 1A to 1C are diagrams illustrating a manufacturing process of the light source module.
• 1A to 1C are diagrams illustrating a manufacturing process of the light source module.
• 1A to 1C are diagrams illustrating a manufacturing process of the light source module.
• 1A to 1C are diagrams illustrating a manufacturing process of the light source module.
• FIG. 11 is a plan view showing another modified example of the optical waveguide package according to the first embodiment of the present disclosure.
• 4 is an enlarged cross-sectional view of yet another modified example of the optical waveguide package according to the first embodiment of the present disclosure taken along the cross-sectional line IV-IV in FIG. 2.
• 4 is an enlarged cross-sectional view of the optical waveguide package according to the second embodiment of the present disclosure taken along the cross-sectional line IV-IV in FIG. 2.
• 4 is an enlarged cross-sectional view of a modified example of the optical waveguide package according to the second embodiment of the present disclosure taken along the cross-sectional line IV-IV in FIG. 2.
• 4 is an enlarged cross-sectional view of another modified example of the optical waveguide package according to the second embodiment of the present disclosure taken along the cross-sectional line IV-IV in FIG. 2.
• 4 is an enlarged cross-sectional view of yet another modified example of the optical waveguide package according to the second embodiment of the present disclosure taken along the section line IV-IV in FIG. 2.
• 4 is an enlarged cross-sectional view of the optical waveguide package according to the third embodiment of the present disclosure taken along the cross-sectional line IV-IV in FIG. 2.
• Patent Document 1 discloses a light source module that includes an optical waveguide layer that is made up of a light-emitting element, a clad, and a core located within the clad.
• optical waveguide package and light source module of the present disclosure may be used with either direction being the top or bottom, but for convenience, in this specification, a Cartesian coordinate system (X, Y, Z) is defined, and the positive side of the Z direction is the top, and terms such as top surface and bottom surface are used.
• the X direction is also referred to as the first direction or length direction.
• the Y direction is also referred to as the second direction or width direction.
• the Z direction is also referred to as the third direction or thickness direction.
• Fig. 1 is an exploded perspective view showing an example of a light source module according to an embodiment of the present disclosure
• Fig. 2 is a plan view showing an example of an optical waveguide package according to an embodiment of the present disclosure
• Fig. 3 is an enlarged plan view showing a part of Fig. 2
• Fig. 4 is a cross-sectional view cut along the cutting line IV-IV in Fig. 2
• Fig. 5 is an enlarged cross-sectional view showing a part of Fig. 4.
• Fig. 6A is an enlarged plan view showing another example of an optical waveguide package according to an embodiment of the present disclosure
• Fig. 6B is a cross-sectional view cut along the cutting line VIB-VIB in Fig. 6A.
• the enlarged cross-sectional view shown in Fig. 6A corresponds to the enlarged plan view shown in Fig. 3.
• the light source module 100 of this embodiment includes an optical waveguide package 1, a light emitting element 7, and a lid 12.
• the optical waveguide package 1 includes a substrate 2, a clad 3, and a core 5.
• the substrate 2 has a first surface 2a, on which an optical waveguide layer 6 composed of a clad 3 and a core 5 is located.
• the substrate 2 may be an organic wiring substrate made of an organic material.
• the organic wiring substrate may be, for example, a printed wiring substrate, a build-up wiring substrate, a flexible wiring substrate, etc.
• organic materials used for organic wiring substrates include epoxy resin, polyimide resin, polyester resin, acrylic resin, phenolic resin, and fluororesin.
• the substrate 2 may be a ceramic wiring board made of a ceramic material.
• ceramic materials used for ceramic wiring boards include aluminum oxide sintered bodies, mullite sintered bodies, silicon carbide sintered bodies, aluminum nitride sintered bodies, and glass ceramic sintered bodies.
• the substrate 2 may be a semiconductor wiring substrate made of a semiconductor material. Examples of semiconductor materials used in semiconductor wiring substrates include Si, Ge, GaN, GaAs, and InP.
• the substrate 2 may be a laminate substrate in which a semiconductor wiring substrate and an insulating layer are laminated, and the first surface 2a is made of the insulating layer.
• the insulating layer may be an inorganic insulating layer such as SiO2 or SiNX, or an organic insulating layer such as an acrylic resin layer or a polycarbonate layer.
• the clad 3 is located on the first surface 2a of the substrate 2.
• the clad 3 has a second surface 3a facing the first surface 2a, and a third surface 3b opposite the second surface 3a.
• the clad 3 has a through hole 4 that penetrates from the third surface 3b to the second surface 3a.
• the core 5 is located within the cladding 3 and extends approximately parallel to the first surface 2a.
• the core 5 has an entrance surface 5a exposed to the inner circumferential surface 4a of the through hole 4 and an exit surface 5b exposed to the end surface of the cladding 3.
• the optical waveguide layer 6 may be made of glass such as quartz, or may be made of resin such as polymethyl methacrylate or fluororesin.
• both the clad 3 and the core 5 may be made of glass or resin, or one of the clad 3 and the core 5 may be made of glass and the other may be made of resin.
• the clad 3 and the core 5 have different refractive indices, and the core 5 has a higher refractive index than the clad 3.
• the optical waveguide layer 6 uses the difference in refractive index between the clad 3 and the core 5 to totally reflect light at the interface between the clad 3 and the core 5.
• the refractive index difference between the clad 3 and the core 5 may be, for example, about 0.05 to 0.30.
• the cladding 3 may be composed of a lower cladding 31 and an upper cladding 32, as shown in FIG. 4.
• the cladding 3 may be composed of a lower cladding 31 located on the first surface 2a, and an upper cladding 32 located on the lower cladding 31.
• the core 5 may be located on the lower cladding 31.
• the light-emitting elements 7 include a light-emitting element 7R that emits red light, a light-emitting element 7G that emits green light, and a light-emitting element 7B that emits blue light.
• the light-emitting elements 7R, 7G, and 7B are also referred to as a red light-emitting element, a green light-emitting element, and a blue light-emitting element, respectively.
• the light-emitting elements 7R, 7G, and 7B may be, for example, light-emitting diodes, semiconductor lasers, etc.
• the semiconductor laser may be an edge-emitting semiconductor laser, or may be a surface-emitting semiconductor laser element.
• the light-emitting elements 7R, 7G, and 7B each have a first terminal and a second terminal.
• the first terminal and the second terminal are electrically connected to an external power supply circuit via a metal film 8 and a wiring conductor 9, etc., which will be described later.
• the core 5 has a plurality of split paths 51R, 51G, 51B, a combining section 52 where the plurality of split paths 51R, 51G, 51B meet, and an integrated path 53 extending between the combining section 52 and the exit surface 5b.
• Each of the plurality of split paths 51R, 51G, 51B has an incident surface 5a exposed to the inner peripheral surface 4a of the through hole 4.
• the incident surface 5a of the split path 51R is indicated by 5aR
• the incident surface 5a of the split path 51G is indicated by 5aG
• the incident surface 5a of the split path 51B is indicated by 5aB.
• the light-emitting elements 7R, 7G, 7B are positioned so that their optical axes pass through the incident surfaces 5aR, 5aG, 5aB, respectively.
• light-emitting element 7 when there is no need to distinguish between the light-emitting elements 7R, 7G, and 7B, they will simply be referred to as "light-emitting element 7".
• incident surface 5aR, the incident surface 5aG, and the incident surface 5aB when there is no need to distinguish between the incident surface 5aR, the incident surface 5aG, and the incident surface 5aB, they will simply be referred to as "incident surface 5a.”
• the division path 51R, the division path 51G, and the division path 51B may be referred to as the core 51R, the core 51G, and the core 51B, respectively.
• the first surface 2a of the substrate 2 includes a first region 21 exposed from the through hole 4 and a second region 22 covered by the clad 3.
• the first region 21 includes an element mounting region 21a and a wiring region 21b.
• the element mounting region 21a is a region where the light-emitting element 7 is mounted. As shown in FIG. 2, the element mounting region 21a is located closer to the incident surface 5a in a plan view.
• the wiring region 21b is located on the opposite side of the element mounting region 21a from the incident surface 5a.
• a metal film 8 is located in the element mounting region 21a, and the light-emitting element 7 is mounted on the metal film 8 so that the first terminal is electrically connected to the metal film 8.
• the second region 22 does not have to be the entire region covered by the clad 3.
• the second region 22 may be a region located directly below the core 5 on the first surface 2a, that is, a region that completely overlaps with the core 5 in a plan view.
• the second region 22 is also called
• the first surface 2a includes a third region 23 in addition to the first region 21 and the second region 22.
• the third region 23 is a region that is not covered by the cladding 3 and is different from the first region 21.
• the third region 23 is also called the external connection region.
• the external connection region 23 may be located at the edge of the first surface 2a, as shown in Figures 2 and 4.
• the optical waveguide package 1 is configured such that the surface roughness of the element mounting region 21a is greater than the surface roughness of the second region 22.
• the surface roughness may be expressed as the arithmetic mean roughness Ra.
• the arithmetic mean roughness Ra may be measured, for example, by an AFM (Atomic Force Microscope).
• the element mounting region 21a may have an arithmetic mean roughness Ra of 1 nm or more and 1000 nm or less.
• the second region 22 may have an arithmetic mean roughness Ra of 0.1 nm or more and 10 nm or less.
• the optical waveguide package 1 includes a metal film 8 located on the element mounting area 21a.
• the metal film 8 is also referred to as an electrode.
• the light-emitting element 7 is mounted on the electrode 8, and a first terminal is electrically connected to the electrode 8.
• the electrode 8 is electrically connected to an external power supply circuit via a wiring conductor 9. As shown in Figures 2 and 4, at least a portion of the electrode 8 is located in the wiring area 21b, and covers one end of the wiring conductor 9 (a first wiring conductor 91 described later).
• a plurality of electrodes 8 are provided according to the number of light-emitting elements 7, and the plurality of electrodes 8 are spaced apart from each other.
• the electrode 8 may be composed of a metal material whose main component is, for example, a metal such as Cr, Ti, Al, Cu, Ag, Au, or Ni, or an alloy of these metals.
• the electrode 8 may be a metal thin film formed using a thin film formation method such as vapor deposition, sputtering, or ion plating.
• the electrode 8 may have a thickness of, for example, 0.5 ⁇ m or more and 5 ⁇ m or less, or 1 ⁇ m or more and 5 ⁇ m or less.
• the electrode 8 has a bottom surface 8a facing the first surface 2a, and a top surface 8b opposite the bottom surface 8a.
• the bottom surface 8a is in close contact with the element mounting region 21a.
• the top surface 8b is roughened and has a larger surface roughness than the second region 22.
• the top surface 8b may have an arithmetic mean roughness Ra of, for example, 1 nm or more and 1000 nm or less.
• the surface roughness of the top surface 8b may reflect the surface roughness of the element mounting region 21a.
• the surface roughness of the element mounting region 21a may be determined so that the surface roughness of the top surface 8b is larger than the surface roughness of the second region 22.
• the surface roughness of the element mounting area 21a of the optical waveguide package 1 is large, so the surface roughness of the upper surface 8b of the electrode 8 can be made large.
• light emitted from the light-emitting element 7 that does not enter the core 5 (hereinafter also referred to as stray light) can be diffusely reflected by the upper surface 8b of the electrode 8.
• the possibility of stray light entering the core 5 can be reduced, and the quality of the emitted light can be improved.
• the core 5 is located above the core formation region 22, which has a small surface roughness, so that the interface between the cladding 3 and the core 5 has small irregularities and fluctuations in the refractive index.
• the loss of light in the optical waveguide layer 6 can be reduced, and the optical propagation efficiency of the optical waveguide layer 6 can be improved.
• the light source module 100 has a large surface roughness in the element mounting area 21a, the contact area between the substrate 2 and the electrode 8 is increased, and the adhesive strength between the substrate 2 and the electrode 8 can be improved.
• the thermal expansion difference between the electrode 8 in contact with the light emitting element 7 and the substrate 2 not in contact with the light emitting element 7 can be reduced, and peeling of the electrode 8 can be reduced. This in turn improves the reliability of the light source module 100.
• the contact area between the substrate 2 and the electrode 8 is increased in the light source module 100, heat generated in the light emitting element 7 and transferred from the light emitting element 7 to the electrode 8 can be easily dissipated to the substrate 2.
• the thermal expansion difference between the electrode 8 in contact with the light emitting element 7 and the substrate 2 not in contact with the light emitting element 7 can be reduced, and peeling of the electrode 8 can be reduced.
• the surface area of the upper surface 8b of the electrode 8 is increased in the light guide package 1 compared to when the upper surface 8b of the electrode 8 is flat, heat generated in the light emitting element 7 and transferred from the light emitting element 7 to the electrode 8 can be easily dissipated to the space in the through hole 4 in which the light emitting element 7 is accommodated.
• the thermal expansion difference between the electrode 8 and the substrate 2 can be further reduced, peeling of the electrode 8 from the substrate 2 can be further reduced, and the reliability of the light source module 100 can be further improved.
• the optical waveguide package 1 includes a wiring conductor 9 located in the wiring region 21b. As shown in FIG. 5, the wiring conductor 9 extends from the wiring region 21b through the second region 22 to the third region 23.
• the wiring conductor 9 may be composed of a metal material mainly composed of a metal such as Cr, Ti, Al, Cu, Ag, Au, or Ni, or an alloy thereof.
• the wiring conductor 9 may be a metal thin film formed using a thin film formation method such as vapor deposition, sputtering, or ion plating.
• the wiring conductor 9 electrically connects the light-emitting element 7 to an external power supply circuit.
• Two wiring conductors 9 (a first wiring conductor 91 and a second wiring conductor 92) are provided for each of the light-emitting elements 7R, 7G, and 7B.
• the first wiring conductor 91 has one end located in the wiring region 21b connected to the electrode 8, and the other end located in the third region 23 electrically connected to an external power supply circuit. At least a portion of the electrode 8 is located in the wiring region 21b and may cover one end of the first wiring conductor 91.
• the second wiring conductor 92 has one end located in the wiring region 21b electrically connected to the second terminal of the light-emitting element 7 via a connection member 14 such as a bonding wire (see FIG. 1), and the other end located in the third region 23 electrically connected to an external power supply circuit.
• a connection member 14 such as a bonding wire (see FIG. 1)
• the wiring conductor 9 may have a smaller surface roughness of the upper surface 9b in the portion located in the second region 22 (hereinafter also referred to as the second portion) than the surface roughness of the upper surface 9a in the portion located in the wiring region 21b (hereinafter also referred to as the first portion).
• the first portion the surface roughness of the upper surface 9a in the portion located in the wiring region 21b.
• stray light is diffusely reflected in the first portion and is less likely to enter the core 5
• stray light that enters the second portion from the inside i.e., the space inside the through hole 4
• the possibility of stray light entering the core 5 can be reduced, and the quality of the emitted light of the light source module 100 can be improved.
• the surface roughness of the upper surface 9a of the first portion of the first wiring conductor 91 is large, the contact area between the first wiring conductor 91 and the electrode 8 can be increased, and the adhesive strength between the first wiring conductor 91 and the electrode 8 can be improved. As a result, peeling between the electrode 8 and the first wiring conductor 91 can be reduced. This improves the reliability of the light source module 100.
• the surface roughness of the upper surface 9a of the first portion of the second wiring conductor 92 is large, the contact area between the conductive bonding material that bonds the second wiring conductor 92 and the connection member 14 and the second wiring conductor 92 can be increased, and the adhesive strength between the second wiring conductor 92 and the connection member 14 can be improved. As a result, detachment of the connection member 14 from the second wiring conductor 92 can be reduced, and the reliability of the light source module 100 can be improved.
• the optical waveguide package 1 may be configured such that the portion (exposed portion) not covered by the wiring conductor 9 in the wiring region 21b has a surface roughness greater than that of the second region 22. In this case, stray light can be diffusely reflected at the exposed portion of the wiring region 21b. As a result, the possibility of stray light entering the core 5 can be reduced, and the quality of the emitted light of the light source module 100 can be improved.
• the optical waveguide package 1 may be configured such that the surface roughness of the interface between the lower surface of the wiring conductor 9 and the first surface 2a is smaller than the surface roughness of the upper surface 9a of the first portion of the wiring conductor 9.
• the thickness of the wiring conductor 9 can be well controlled in the manufacturing process of the optical waveguide package 1, and the possibility that the wiring conductor 9 will become locally highly resistant or break can be reduced. As a result, the reliability of the light source module 100 can be improved.
• the surface roughness of the wiring conductor 9 at the portion located in the third region 23 may be greater than the surface roughness of the second region 22.
• external light incident on the upper surface 9c of the third region can be diffusely reflected by the upper surface 9c.
• the possibility of external light entering the space inside the through hole 4 and entering the core 5 can be reduced. This in turn can improve the quality of the emitted light of the light source module 100.
• the optical waveguide package 1 may be configured such that the surface roughness of the third region 23 is greater than the surface roughness of the second region 22. In this case, external light that is incident on the third region 23 can be diffusely reflected. As a result, the possibility that external light will enter the space inside the through hole 4 and enter the core 5 can be reduced.
• the surface roughness of the third region 23 may be approximately the same as the exposed portion of the wiring region 21b.
• the surface roughness of the third region 23 may be less than the surface roughness of the element mounting region 21a.
• the wiring conductor 9 may have a surface roughness of the upper surface 9c of the third portion greater than the surface roughness of the upper surface 9b of the second portion.
• external light incident on the upper surface 9c of the third portion can be diffusely reflected by the upper surface 9c.
• the possibility of external light entering the space inside the through hole 4 and entering the core 5 can be reduced. This in turn can improve the quality of the emitted light from the light source module 100.
• the substrate 2 may have a first recess 10 recessed in the thickness direction (Z direction) from the first surface 2a.
• the first recess 10 may be located closer to the incident surface 5a in the element mounting area 21a in a plan view.
• stray light can be guided into the first recess 10 and reflected by the inner surface of the first recess 10, thereby reducing the possibility of the stray light entering the core 5.
• being located closer to the incident surface 5a means that the distance from the first recess 10 to the inner surface 4a on the side where the incident surface 5a is located is closer than the distance from the first recess 10 to the inner surface 4a on the side opposite the incident surface 5a in the X direction.
• the first recess 10 may have a shape in a plan view that is, for example, rectangular, square, trapezoidal, or other shape.
• the first recess 10 may have a shape in a side view that is, for example, rectangular, square, trapezoidal, or other shape.
• the first recess 10 may be located closer to the incident surface 5a than the electrode 8 in a plan view. In this case, stray light can be effectively guided into the first recess 10 and reflected by the inner surface of the first recess 10, further reducing the possibility of stray light entering the core 5. As a result, the quality of the emitted light from the light source module 100 can be further improved.
• the optical waveguide package 1 may have multiple (e.g., three) first recesses 10.
• the multiple first recesses 10 may be located one by one between each of the multiple electrodes 8 and the inner surface 4a of the through hole 4.
• the optical waveguide package 1 may have a single first recess 10 as shown in FIG. 6A.
• the inner surface 4a here may be a portion including the incident surfaces 5aR, 5aG, and 5aB on the inner surface 4a.
• the single first recess 10 may be located between the multiple electrodes 8 and the inner surface 4a of the through hole 4 and may have a width approximately equal to the width of the through hole 4.
• the first recess 10 is located in almost the entire area between the light-emitting element 7 and the incident surfaces 5aR, 5aG, and 5aB, so that the possibility of stray light entering the core 5 can be further reduced.
• the optical waveguide package 1 has multiple first recesses 10, the possibility of the strength of the substrate 2 being reduced can be reduced.
• the single or multiple first recesses 10 may have a length of 1 ⁇ m to 100 ⁇ m in the first direction (X direction).
• the possibility of stray light entering the core 5 can be reduced, and the distance between the light-emitting element 7 and the incident surfaces 5aR, 5aG, and 5aB does not become too large, so the efficiency of the light emitted from the light-emitting element 7 entering the core 5 can be increased.
• the first recess 10 has a bottom surface 10a and an inner peripheral surface 10b.
• the bottom surface 10a is a surface that is approximately parallel to the first surface 2a
• the inner peripheral surface 10b is a surface that connects the bottom surface 10a and the first surface 2a.
• the bottom surface 10a and the inner peripheral surface 10b may be roughened.
• the bottom surface 10a and the inner peripheral surface 10b may have a surface roughness greater than that of the second region 22.
• the stray light can be diffusely reflected by the bottom surface 10a and the inner peripheral surface 10b, so that the possibility of the stray light entering the core 5 can be further reduced.
• the quality of the emitted light of the light source module 100 can be further improved.
• the bottom surface 10a and the inner peripheral surface 10b may have a surface roughness greater than that of the upper surface of the electrode 8, and may also have a surface roughness greater than that of the element mounting region 21a.
• the optical waveguide package 1 may be configured such that a portion of the inner circumferential surface 4a of the through hole 4 (hereinafter also referred to as a portion of the first surface) and a portion of the inner circumferential surface 10b of the first recess 10 (hereinafter also referred to as a portion of the second surface) are flush with each other.
• stray light can be effectively guided into the first recess 10 and diffusely reflected by the bottom surface 10a and the inner circumferential surface 10b of the first recess 10. This can further reduce the possibility that stray light will enter the core 5.
• the portion of the first surface of the through hole 4 and the portion of the second surface of the first recess 10 may be configured such that the portion of the first surface includes the incident surfaces 5aR, 5aG, and 5aB.
• the optical waveguide package 1 may include an optical element 11, as shown in Figs. 2 and 4.
• the optical element 11 is located on the optical path of the light emitted from the exit surface 5b of the core 5.
• the optical element 11 may be configured to collimate the light emitted from the exit surface 5b, or may be configured to focus the light emitted from the exit surface 5b.
• the optical element 11 may be a lens.
• the optical element 11 may be a plano-convex lens in which the lens entrance surface facing the exit surface 5b is flat and the lens exit surface opposite the lens entrance surface is convex.
• the lid 12 of the light source module 100 is located on the third surface 3b of the clad 3 and closes the opening of the through hole 4.
• the lid 12 may be directly bonded to the clad 3.
• the lid 12 may be bonded to the clad 3 via a seal ring 13.
• the seal ring 13 has an annular shape and surrounds the opening of the through hole 4 in a plan view. By providing the seal ring 13, it is possible to increase the airtightness of the space in which the light emitting element 7 is housed.
• the lid 12 may be directly bonded to the clad 3, for example by heat bonding, but in that case, the stress generated during bonding may distort the clad 3 and core 5, causing optical axis misalignment between the light-emitting element 7 and core 5.
• the mechanical strength of the area around the through hole 4 in the clad 3 can be increased.
• distortion of the clad 3 and core 5 can be reduced, and optical axis misalignment between the light-emitting element 7 and core 5 can be reduced.
• the lid 12 may be made of a glass material such as quartz, borosilicate glass, or sapphire.
• the lid 12 may be made of a metal material such as Fe, Ni, or Co, or an alloy material containing these metals.
• the seal ring 13 may be made of a metal material such as Ti, Ni, Au, Pt, or Cr, or an alloy material containing these metals.
• the seal ring 13 may be fixed to the third surface 3b of the clad 3 by, for example, deposition, sputtering, ion plating, plating, or the like.
• the lid 12 may be bonded to the seal ring 13 using a bonding material such as Au-Sn or Sn-Ag-Cu solder, a metal nanoparticle paste such as Ag or Cu, or a glass paste.
• Figures 7A to 7L are end views illustrating the manufacturing process for the light source module 100.
• the substrate 2 is prepared.
• the substrate 2 may be an organic wiring substrate or a ceramic wiring substrate.
• the substrate 2 may be a laminated substrate in which a semiconductor wiring substrate and an insulating layer are laminated.
• an etching mask 101 made of a resist material is formed on the first surface 2a of the substrate 2, exposing a portion of the first surface 2a that will become the element mounting area 21a.
• a portion of the first surface 2a is roughened by etching such as reactive ion etching (RIE), and then the etching mask 101 is removed as shown in FIG. 7C.
• RIE reactive ion etching
• the wiring conductors 9 are formed on the first surface 2a.
• two wiring conductors 9 i.e., a first wiring conductor 91 and a second wiring conductor 92
• the wiring conductors 9 can be formed using a thin-film formation method such as vapor deposition, sputtering, or ion plating.
• a clad layer 102 is formed on the first surface 2a, and a core layer 103 is formed on the clad layer 102.
• an etching mask 104 is formed to cover a portion of the core layer 103.
• the etching mask 104 covers the portion of the core layer 103 that will become the core 5.
• the etching mask 104 may also cover the portion of the core layer 103 that will become the partition wall surrounding the through hole 4.
• FIG. 7G the portion of the core layer 103 exposed from the etching mask 104 is removed by etching such as RIE to form the portion that will become the partition wall surrounding the core 5 and the through hole 4.
• clad layer 105 is formed on clad layer 102 and core layer 103.
• an etching mask 106 is formed on the cladding layer 105 to cover a portion of the cladding layer 105.
• the etching mask 106 exposes the portions that will become the first region 21 and the third region 23.
• the cladding layer, core layer, and cladding layer exposed from the etching mask 106 are removed by etching such as RIE, to expose the first region 21 and the third region 23 as shown in FIG. 7J.
• the element mounting region 21a is roughened, and the wiring region 21b and the portions exposed from the wiring conductor 9 in the third region 23 are roughened.
• the upper surface of the portion of the wiring conductor 9 located in the wiring region 21b and the upper surface of the portion located in the third region 23 are roughened.
• the element mounting area 21a is roughened by the etching in the process of FIG. 7B and the etching in the process of FIG. 7J.
• the element mounting area 21a has a greater surface roughness than the areas not etched (the second area 22 and the top surface 9b of the second part of the wiring conductor 9).
• the element mounting area 21a also has a greater surface roughness than the areas roughened only by the etching in the process of FIG. 7J (the top surfaces 9a, 9c of the first and third parts of the wiring conductor 9, etc.).
• a core 5 is formed having an incident surface 5a exposed on the inner surface 4a of the through hole 4.
• the optical waveguide package 1 can be manufactured by forming an electrode 8 that is located in the element mounting area 21a and covers one end of the wiring conductor 9 (first wiring conductor 91).
• the electrode 8 can be formed using a thin film formation method such as vapor deposition, sputtering, or ion plating.
• the upper surface 8b of the electrode 8 reflects the surface roughness of the element mounting area 21a and has a relatively large surface roughness.
• the light-emitting element 7 is mounted on the electrode 8.
• the first terminal of the light-emitting element 7 is electrically connected to the electrode 8 using a conductive bonding material such as solder.
• the second terminal of the light-emitting element 7 is electrically connected to one end of the wiring conductor 9 (second wiring conductor 92) via a connection member 14 such as a bonding wire.
• the optical element 11 is attached to the emission surface 5b of the core 5, and further, the cover 12 is attached to the upper surface of the cladding layer 105 via a seal ring 13, thereby manufacturing the light source module 100.
• the above-mentioned manufacturing method is a method for manufacturing an optical waveguide package 1 that does not have a first recess 10, but an optical waveguide package 1 that has a first recess 10 can also be manufactured in the same way.
• the first recess 10 can be formed, for example, in the step of FIG. 7J, by etching the portion of the substrate 2 where the first recess 10 should be located.
• the surface roughness of the bottom surface 10a and the inner surface 10b of the first recess 10 can be greater than the surface roughness of the element mounting area 21a.
• the surface roughness of the element mounting region 21a can be made greater than the surface roughness of the second region 22.
• the surface roughness of the element mounting region 21a and the metal film (electrode) 8 on the element mounting region 21a can be made greater.
• the reliability of the light source module 100 can be further improved.
• the surface roughness of the area close to the incident surfaces 5aR, 5aG, and 5aB greater, stray light can be effectively diffused and reflected.
• the wiring conductor 9, cladding 3, and core 5 may be formed after forming a region with high surface roughness (a region with a surface roughness greater than that of the second region 22) and the first recess 10 at a predetermined position on the substrate 2.
• the surface roughness of the portions of the first surface 2a of the substrate 2 that will become the first region 21 and the third region 23 may be increased by etching, and the first recess 10 may be formed, after which the wiring conductor 9, cladding 3, and core 5 may be formed on the first surface 2a.
• FIG. 1 shows an example in which red light-emitting elements 7R, green light-emitting elements 7G, and blue light-emitting elements 7B are arranged in this order in the second direction (Y direction), but the red light-emitting elements 7R, green light-emitting elements 7G, and blue light-emitting elements 7B may be arranged in any order. Also, while FIGS.
• red light-emitting elements 7R, green light-emitting elements 7G, and blue light-emitting elements 7B are arranged to emit light in directions parallel to each other, the red light-emitting elements 7R, green light-emitting elements 7G, and blue light-emitting elements 7B may be arranged to emit light in directions non-parallel to each other.
• FIG. 8 is a plan view showing another modified example of the optical waveguide package according to the embodiment of the present disclosure.
• the plan view shown in FIG. 8 corresponds to the plan view shown in FIG. 2.
• the optical waveguide package 1A of this embodiment may have three cores 51R, 51G, 51B that are independent of each other, as shown in FIG. 8.
• the three incident surfaces 5aR, 5aG, 5aB are positioned apart from each other in accordance with the positions of the light-emitting elements 7R, 7G, 7B so that the centers of the incident surfaces 5aR, 5aG, 5aB of the three cores 51R, 51G, 51B coincide with the optical axes of the light-emitting elements 7R, 7G, 7B mounted on the optical waveguide package 1A.
• the exit surfaces 5bR, 5bG, 5bB of the three cores 51R, 51G, 51B are positioned close to each other.
• the three cores 51R, 51G, 51B may be collected close to each other and extend parallel to the exit surfaces 5bR, 5bG, 5bB.
• the collecting section may be called a multiplexing section 52.
• the light emitted from each of the cores 51R, 51G, 51B may be emitted in parallel by one optical element 11.
• the light emitted from each of the cores 51R, 51G, 51B may be combined by an external device.
• FIG. 9 is an enlarged cross-sectional view of yet another modified example of an optical waveguide package according to an embodiment of the present disclosure, taken at a location corresponding to the cross-sectional line IV-IV in FIG. 2.
• the optical waveguide package 1B of this modified example is different in that the wiring conductor 9 extends to the back surface 2b of the substrate 2. More specifically, a through conductor 9D penetrating the substrate 2 may be connected to a conductor located on the first surface 2a, and the through conductor 9D may be further connected to a conductor located on the back surface 2b. With this configuration, the wiring conductor 9 does not need to be provided behind the through hole 4 (i.e., in the positive direction of the X-axis), so the dimension of the optical waveguide package 1B in the X-direction can be reduced. In addition, with this configuration, the optical waveguide package 1B can be connected to a printed circuit board or the like by a conductive bonding material such as solder. In FIG.
• the through conductor 9D is located at a position overlapping the through hole 4 in a plan view, but for example, the wiring conductor 9 may extend to between the clad 3 and the substrate 2, and the through conductor 9D may overlap the clad 3 in a plan view. Furthermore, if the optical waveguide package 1B has multiple wiring conductors 9, it is not necessary for all of the wiring conductors 9 to extend to the rear surface 2b of the substrate 2, and only some of the wiring conductors 9 may extend to the rear surface 2b of the substrate 2. Also, the metal film 8 is not necessarily required.
• the optical waveguide package 1C according to the second embodiment is different from the first embodiment in that the clad 3 has an opening 41. That is, the clad has a second surface 3a facing the first surface 2a, a third surface 3b located on the opposite side to the second surface 3a, and an opening 41 that opens into the third surface 3b.
• the first surface 2a has a covered area 21c covered by the cladding 3.
• the opening 41 has a bottom 4b.
• the bottom 4b has an element mounting area 21a.
• the surface roughness of the element mounting area 21a is greater than the surface roughness of the covered area 21c.
• the optical waveguide package 1C can increase the contact area between the substrate 2 and the metal film 8. This can improve the adhesion strength between the wiring conductor 9 and the electrode 8. As a result, peeling between the electrode 8 and the wiring conductor 9 can be reduced.
• the wiring conductor 9 may have a first portion 9A located at the bottom 4b and a second portion 9B located within the cladding 3.
• the surface roughness of the second portion 9B may be smaller than the surface roughness of the first portion 9A.
• the metal film 8 may be located in the element mounting area 21a and cover a portion of the wiring conductor 9. With this configuration, the wiring conductor 9 is held down by the metal film 8, reducing the possibility of the wiring conductor 9 peeling off.
• the wiring conductor 9 may have a portion located within the opening 41 and penetrating the clad 3.
• the wiring conductor 9 may have a first portion 9A located at the bottom 4b, a second portion 9B located within the clad 3, and a third portion 9C located on the clad 3 outside the opening 41.
• the surface roughness of the third portion 9C may be greater than the surface roughness of the coated region 21c.
• the optical waveguide package 1D substrate according to the modified example of the second embodiment may have a first recess 10 recessed in the thickness direction from the first surface 2a.
• the bottom 4b may include a hole 4c reaching the second surface 3a.
• the hole 4c and the first recess 10 may overlap in a plan view. More specifically, the hole 4c and the first recess 10 may be located closer to the incident surface 5a in the opening 41 in a plan view.
• the hole 4c and the inner surface 10b of the first recess 10 are flush with each other, but this is not necessarily required.
• the dimension of the hole 4c in the X direction may be larger than the dimension of the first recess 10 in the X direction.
• the hole 4c does not necessarily have to be flush with the inner circumferential surface 4a of the opening 41. In other words, the hole 4c may be spaced apart from the inner circumferential surface 4a of the opening 41.
• the hole 4c and the first recess 10 may be located between the element mounting area 21a and the core 5. In this case, the possibility that heat generated in the light-emitting element 7 is transferred to the optical waveguide layer 6 can be reduced. As a result, the possibility that the core 5 is deformed by heat can be reduced.
• the surface roughness of the bottom surface 10a and the inner peripheral surface 10b of the first recess 10 may be greater than the surface roughness of the covering region 21c.
• the substrate 2 may have a second recess 15 recessed in the thickness direction (i.e., Z direction) from the first surface 2a.
• the second recess 15 may overlap the opening 41.
• the bottom 4b of the opening 41 may be lower in the Z direction than the first surface 2a of the cladding 3 on the side where the incident surface 5a of the core 5 is located.
• the substrate 2 may also have a first recess 10, and in this case, the first recess 10 may be located within the aforementioned second recess 15.
• the bottom 4b may include a hole 4c that reaches the second surface 3a.
• the wiring conductor 9 may penetrate the substrate 2 and extend to the rear surface 2b of the substrate 2, similar to the optical waveguide package 1B.
• the wiring conductor 9 also penetrates the bottom 4b of the opening 41.
• the optical waveguide package 1G according to the third embodiment differs from the other embodiments in that it includes an insulating film 33 located on the first surface 2a, at least a portion of which is located within the through hole 4.
• the insulating film 33 has an insulating region 21d exposed within the through hole 4.
• the insulating region 21d may include the element mounting region 21a.
• the surface roughness of the element mounting region 21a may be greater than the surface roughness of the internal region 21e.
• the light source module 100 can diffusely reflect light emitted from the light-emitting element 7 and not entering the core 5 at the element mounting region 21a, the upper surface 8b of the electrode 8, or the upper surface 9a of the wiring conductor 9. As a result, the possibility of stray light entering the core 5 can be reduced.
• the insulating film 33 is located all over the space between the substrate 2 and the clad 3, but this is not necessary. For example, it may be located only in a position that overlaps with the through hole 4 in a plan view, or it may be located only on the side between the clad 3 and the substrate 2 opposite the incident surface 5a of the core 5.
• the optical waveguide package 1G according to the third embodiment may further include a wiring conductor 9 at least a portion of which is located on the insulating film 33.
• the wiring conductor 9 may have a first portion 9A located on the insulating region 21d and a second portion 9B located on the internal region 21e.
• the surface roughness of the second portion 9B may be smaller than the surface roughness of the first portion 9A.
• the optical waveguide package 1G according to the third embodiment may further include a metal film 8 located on the insulating film 33.
• the metal film 8 may be located in the element mounting area 21a and may cover a portion of the wiring conductor 9. With this configuration, the wiring conductor 9 is held down by the metal film 8, reducing the possibility of the wiring conductor 9 peeling off.
• the wiring conductor 9 may be at least partially located on the insulating film 33 and may penetrate the clad 3. In other words, the wiring conductor 9 may be located from the inside of the opening 41 to the outside of the opening 41.
• the wiring conductor 9 may have a first portion 9A located in the insulating region 21d, a second portion 9B located in the clad 3, and a third portion 9C located on the insulating film 33 or on the first surface 2a outside the through hole 4. In this case, the surface roughness of the third portion 9C may be greater than the surface roughness of the internal region 21e.
• the light from the outside incident on the upper surface 9c of the third portion 9C can be diffusely reflected by the upper surface 9c.
• the possibility that the light from the outside will enter the space inside the through hole 4 and enter the core 5 can be reduced.
• the optical waveguide package disclosed herein can reduce the possibility of stray light entering the core, thereby improving the quality of the emitted light from the light source module.
• the light source module disclosed herein is equipped with the optical waveguide package described above, and is therefore capable of emitting high-quality emitted light.
• optical waveguide package and light source module disclosed herein can be implemented in the following configurations (1) to (20).
• a substrate having a first surface; a clad located on the first surface, the clad having a second surface facing the first surface, a third surface located on the opposite side of the second surface, and a through hole extending from the third surface to the second surface; a core located within the cladding, the core having an entrance surface exposed to an inner circumferential surface of the through hole and an exit surface exposed to an end surface of the cladding, the first surface has a first region exposed from the through hole and a second region covered with the cladding, The first region includes an element mounting region, and a surface roughness of the element mounting region is greater than a surface roughness of the second region.
• the first surface has a third region that is not covered by the cladding and is different from the first region,
• the substrate has a first recess recessed in a thickness direction from the first surface,
• the optical waveguide package according to any one of the above configurations (1) to (4), wherein the first recess is located closer to the incident surface in the first region in a plan view.
• An optical waveguide package according to any one of the above configurations (1) to (7), further comprising an optical element located on the optical path of the light emitted from the exit surface.
• a substrate having a first surface; a clad located on the first surface, the clad having a second surface facing the first surface, a third surface located on the opposite side to the second surface, and an opening opening into the third surface; a core located within the cladding, the core having an entrance surface exposed on an inner circumferential surface of the opening and an exit surface exposed on an end surface of the cladding, The opening has a bottom.
• the first surface has a coating region coated with the cladding; the bottom portion has a device mounting area, An optical waveguide package, wherein the surface roughness of the element mounting region is greater than the surface roughness of the covering region.
• a wiring conductor is further provided, the wiring conductor being partially located within the opening and penetrating the clad, the wiring conductor has a first portion located at the bottom, a second portion located within the clad, and a third portion located on the clad outside the opening,
• the substrate has a first recess recessed in a thickness direction from the first surface, the bottom portion includes a hole reaching the second surface,
• the optical waveguide package according to any one of the above configurations (9) to (12), wherein the hole and the first recess overlap in a plan view.
• the substrate has a second recess recessed in a thickness direction from the first surface,
• the optical waveguide package according to any one of the above configurations (9) to (12), wherein, in a plan view, the second recess overlaps with the opening.
• a substrate having a first surface; a clad located above the first surface, the clad having a second surface facing the first surface, a third surface located on the opposite side of the second surface, and a through hole extending from the third surface to the second surface; a core located within the cladding, the core having an entrance surface exposed on an inner peripheral surface of the through hole and an exit surface exposed on an end surface of the cladding; an insulating film located on the first surface, at least a portion of which is located within the through hole; the insulating film has an insulating region exposed in the through hole, When a region of the insulating film or the first surface covered with the clad is defined as an internal region, the insulating region includes an element mounting region, The surface roughness of the element mounting region is greater than the surface roughness of the internal region.
• the semiconductor device further includes a wiring conductor, at least a portion of which is located on the insulating film and which penetrates the clad; the wiring conductor has a first portion located in the insulating region, a second portion located in the clad, and a third portion located outside the through hole on the insulating film or on the first surface,

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• Physics & Mathematics (AREA)
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• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
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• Optical Couplings Of Light Guides (AREA)
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• 2024
  • 2024-03-19 JP JP2025510604A patent/JPWO2024203659A1/ja active Pending
  • 2024-03-19 WO PCT/JP2024/010854 patent/WO2024203659A1/ja not_active Ceased
  • 2024-03-21 TW TW113110573A patent/TW202443215A/zh unknown

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