JP5781006B2 - WIRING BOARD FOR LIGHT EMITTING ELEMENT AND LIGHT EMITTING DEVICE - Google Patents

Description

  The present invention relates to a wiring board for a light emitting element used for a lighting device (for example, LED lighting or a signal lamp) or a display device (for example, an LED display), and a light emitting device including the same.

  2. Description of the Related Art Conventionally, a light-emitting device in which a light-emitting element is mounted on a wiring board for a light-emitting element is used as a light-emitting device used in a lighting device or a display device.

  As this light emitting element wiring board, for example, as disclosed in Patent Document 1, the upper surface on which the light emitting element is mounted is configured by an insulating layer made of a resin material.

  By the way, a light emitting device in which a light emitting element is mounted on a light emitting element wiring board is provided with, for example, a cover member for protecting the light emitting element, and a part of visible light emitted from the light emitting element is covered. It may be reflected by the member and reach the upper surface of the light emitting element wiring board. Here, when the upper surface of the wiring substrate for light emitting elements is generally constituted by an insulating layer made of a resin material that easily absorbs visible light, visible light is not easily reflected on the upper surface of the wiring substrate for light emitting elements. Therefore, the visible light reflected by the cover member is absorbed on the upper surface of the light emitting element wiring substrate. That is, since a part of visible light emitted from the light emitting element is lost, there arises a problem that the brightness of the light emitting device is easily lowered.

JP 2004-39691 A

  An object of this invention is to provide the wiring board for light emitting elements which can improve the brightness of a light-emitting device, and a light-emitting device using the same.

  A light-emitting element wiring board according to an embodiment of the present invention is a light-emitting element wiring board on which a light-emitting element including a light-emitting portion that emits light upward is mounted, and includes a first resin layer constituting an upper surface And a first inorganic insulating layer laminated on the first resin layer, wherein the first inorganic insulating layer has a particle size smaller than the lower limit of the wavelength of visible light, A plurality of first inorganic insulating particles connected at a portion, and a plurality of spherical second inorganic insulating particles surrounded by the plurality of first inorganic insulating particles having a particle size larger than the lower limit of the wavelength of visible light. And a gap surrounded by the plurality of first inorganic insulating particles and the plurality of second inorganic insulating particles is formed, and from the upper surface of the first insulating layer to the inside of the first insulating layer It is characterized by being located at a depth to which the entering visible light reaches.

According to the light emitting element wiring substrate according to the embodiment of the present invention, the first insulating layer constituting the upper surface of the light emitting element wiring substrate has the first inorganic insulating layer, and the first inorganic insulating layer is Since the visible light entering the inside of the first insulating layer reaches the depth from the upper surface of the first insulating layer, the visible light reaching the upper surface of the wiring board for light emitting elements is Will reach the layer. And since the particle diameter of the 1st inorganic insulating particle in a 1st inorganic insulating layer is smaller than the wavelength of visible light, the visible light which reached the 1st inorganic insulating layer is hard to be reflected by the 1st inorganic insulating particle, and is favorable The visible light that has reached the second inorganic insulating particle and the second inorganic insulating particle is further directed in the same direction as the incident direction by the spherical second inorganic insulating particle that is larger than the wavelength of visible light. Visible light is easily reflected (recursive reflection). As a result, visible light that reaches the upper surface of the wiring board for light emitting elements is reflected upward, so that the brightness of the light emitting device configured by mounting the light emitting elements on the upper surface of the wiring board for light emitting elements is improved. Can do.

FIG. 1 is a cross-sectional view taken along the thickness direction (Z direction) showing a light emitting device according to an example of an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the thickness direction (Z direction) showing the R1 portion of FIG. 1 in an enlarged manner. FIG. 3 is a cross-sectional view taken along the thickness direction (Z direction) showing an enlarged R2 portion of FIG. (A)-(d) is sectional drawing cut | disconnected in the thickness direction (Z direction) for every process explaining the manufacturing process of the light-emitting device shown in FIG. FIG. 5 is a cross-sectional view taken along the thickness direction (Z direction) showing another example of the embodiment of the light emitting device of the present invention different from FIG. FIG. 6 is a cross-sectional view cut in the thickness direction (Z direction) showing another example of the embodiment of the light emitting device of the present invention different from FIGS. 1 and 5.

<First Embodiment>
(Light emitting device)
Hereinafter, a light-emitting device including a wiring board for a light-emitting element according to a first example (first embodiment) of an embodiment of the present invention will be described in detail with reference to the drawings.

  The light-emitting device 1 shown in FIG. 1 is used for, for example, an illumination device such as an LED illumination or a signal lamp, or a display device such as an LED display. The light emitting device 1 includes a light emitting element 2 that emits light upward, a light emitting element wiring substrate 3 on which the light emitting element 2 is mounted, and a light emitting element 2 for reflecting light emitted from the light emitting element 2 upward. It includes a reflecting plate 4 disposed around and a translucent cover member 5 having both ends supported by the reflecting plate 4 in order to protect the light emitting element 2 and the light emitting element wiring substrate 3.

  In the following, in the thickness direction of the light emitting device 1 (Z direction in the drawing), the light emitting direction of the light emitting device 1 is defined as upward, and the opposite is defined as downward.

(Light emitting element)
The light emitting element 2 is mounted on the upper surface of the light emitting element wiring substrate 3 and connected to the light emitting element wiring substrate 3 through, for example, bonding wires. The light emitting element 2 includes, for example, a base portion 6 for supporting the light emitting portion 7 on the upper surface and connecting to a bonding wire, and a light emitting portion formed of a semiconductor material such as gallium arsenide phosphorus, gallium nitride, or silicon carbide. 7 and a lens portion 8 surrounding the light emitting portion 7.

  The thickness of the light emitting element 2 is set to 0.05 mm or more and 0.9 mm or less, for example. The thickness of the light-emitting element 2 is determined by observing a cross section including the light-emitting part 7 exposed by polishing the light-emitting element 2 in the planar direction (XY plane direction) with an optical microscope. It measures by measuring 10 or more lengths along the thickness direction (Z direction) to the upper surface of 8, and calculating the average value.

(Light-emitting element wiring board)
The light emitting element wiring substrate 3 includes a first insulating layer 9 constituting the upper surface of the light emitting element wiring substrate 3 and a light emitting element wiring that is partially disposed on the upper surface of the first insulating layer 9 together with the first insulating layer 9. Partially between the first conductive layer 10 constituting the upper surface of the substrate 3, the second insulating layer 11 disposed on the lower surface of the first insulating layer 9, and the first insulating layer 9 and the second insulating layer 11. The first conductive layer 10 and the second conductive layer 12 are electrically connected through the second conductive layer 12 and the first insulating layer 9 or the second insulating layer 11 in the thickness direction (Z direction). A via conductor 13 and a metal plate 14 disposed on the lower surface of the second insulating layer 11 are included.

  The thickness of the light emitting element wiring board 3 is set to, for example, 0.1 mm or more and 2 mm or less, and is measured in the same manner as the light emitting element 2.

(First insulation layer)
The first insulating layer 9 is intended to insulate between the first conductive layer 10 and the second conductive layer 12. The first insulating layer 9 includes a first resin layer 15, a first inorganic insulating layer 16 stacked on the top surface of the first resin layer 15, and a surface resin layer 17 stacked on the top surface of the first inorganic insulating layer 16. In the first insulating layer 9, the upper surface of the first inorganic insulating layer 16 is located at a depth at which visible light entering the inside of the first insulating layer 9 reaches from the upper surface of the first insulating layer 9. ing.

  The “depth at which visible light reaches” refers to the area from the upper surface of the first insulating layer 9 in the region of the first insulating layer 9 that constitutes the upper surface of the light emitting element wiring substrate 3 except the mounting region of the light emitting element 2. The distance to the point where at least 80% of the visible light that has entered the first insulating layer 9 arrives. That is, in this embodiment, since the surface resin layer 17 is laminated on the upper surface of the first inorganic insulating layer 16, the surface resin layer 17 in which the visible light transmittance is 80% in the surface resin layer 17. Is the maximum value of “depth at which visible light reaches”.

  Further, the visible light transmittance of the surface resin layer 17 is obtained by polishing the upper and lower surfaces of the light emitting element wiring substrate 3 to take out the first insulating layer 9, and then analyzing the resin material of the surface resin layer 17, A resin layer similar to the surface resin layer 17 is manufactured as a prototype, and can be measured, for example, by measuring the transmittance of the prototype with a transmittance meter.

  Further, the depth at which the visible light reaches differs depending on the wavelength of the visible light, but it is not necessary for the visible light of all wavelengths to reach, and it is sufficient to reach only the visible light of the wavelength emitted from the light emitting element 2. That is, for example, when the light emitting element 2 emits violet visible light, it is sufficient that the wavelength of the minimum visible light reaches, and when the light emitting element 2 emits red visible light, the maximum value of visible light is reached. It is sufficient if the wavelength reaches.

  The thickness of the first insulating layer 9 is set to, for example, 20 μm or more and 100 μm or less. The Young's modulus of the first insulating layer 9 is set to, for example, 20 GPa or more and 45 GPa or less, and the coefficient of thermal expansion in the plane direction (XY plane direction) is set to, for example, 13 ppm / ° C. or more and 19 ppm / ° C. or less. Yes. The thickness of the first insulating layer 9 is measured in the same manner as the light emitting element 2. The Young's modulus of the first insulating layer 9 can be measured by a measuring method according to ISO 527-1: 1993, for example, using a nanoindenter. And the thermal expansion coefficient of the 1st insulating layer 9 is measured by the measuring method according to JISK7197-1991, for example using a commercially available TMA (thermomechanical analysis) apparatus.

(First resin layer)
The first resin layer 15 is a main part of the first insulating layer 9, and includes, for example, a first resin portion 18 made of a resin material such as an epoxy resin, a virmaleimide triazine resin, or a cyanate resin, and filler particles 19a. Is included.

  The thickness of the first resin layer 15 is set to 3 μm or more and 20 μm or less, for example. The Young's modulus of the first resin layer 15 is set to, for example, 1 GPa or more and 10 GPa or less. The coefficient of thermal expansion in the plane direction (XY plane direction) of the first resin layer 15 is set to 20 ppm / ° C. or more and 70 ppm / ° C. or less, for example. The thermal conductivity of the first resin layer 15 is set to, for example, 0.1 W / m · K to 1.5 W / m · K.

  The thickness, Young's modulus, and thermal expansion coefficient of the first resin layer 15 are measured in the same manner as the first insulating layer 9. The thermal conductivity of the first resin layer 15 is measured by, for example, a laser flash method by a measurement method according to JIS C2141-1992.

  The volume ratio (volume%) of the filler particles 19a in the first resin layer 15 is set to, for example, 10 volume% or more and 70 volume% or less. The volume ratio (volume%) of the filler particles 19a is measured by first taking a cross-section exposed by polishing the first resin layer 15 with a scanning electron microscope or a transmission electron microscope, and performing image analysis from the taken image. The area ratio (area%) is measured using an apparatus or the like. Next, the volume ratio (volume%) of the filler particles 19a is measured by regarding the average value calculated from these measured values as the volume ratio of the filler particles 19a.

(Filler particles)
The filler particles 19 a are dispersed in the first resin layer 15, and reduce the thermal expansion coefficient of the first resin layer 15 and improve the Young's modulus of the first resin layer 15. The filler particles 19a are made of, for example, an inorganic insulating material such as titanium oxide, silicon oxide, aluminum oxide, aluminum nitride, aluminum hydroxide, or calcium carbonate.

  The average particle diameter of the filler particles 19a is set to, for example, 0.3 μm or more and 5 μm or less. The average particle diameter of the filler particles 19a is obtained by observing the cross section of the first resin layer 15 with a scanning electron microscope or a transmission electron microscope and photographing an enlarged cross section so as to include 20 or more and 50 or less particles. The maximum diameter of each particle is measured in this enlarged cross section, and the average value is calculated.

(First inorganic insulating layer)
The first inorganic insulating layer 16 reduces the coefficient of thermal expansion of the first insulating layer 9. The thickness of the first inorganic insulating layer 16 is set to, for example, 3 μm or more and 100 μm or less. The Young's modulus of the first inorganic insulating layer 16 is set to, for example, 20 GPa or more and 50 GPa or less. The coefficient of thermal expansion in the plane direction (XY plane direction) of the first inorganic insulating layer 16 is set to, for example, 0.6 ppm / ° C. or more and 10 ppm / ° C. or less. The thermal conductivity of the first inorganic insulating layer 16 is set to, for example, 0.2 W / m · K or more and 3 W / m · K or less. The thickness, Young's modulus, thermal expansion coefficient, and thermal conductivity of the first inorganic insulating layer 16 are measured in the same manner as the first resin layer 15.

  Such a first inorganic insulating layer 16 includes a plurality of first inorganic insulating particles 20 and a plurality of second inorganic insulating particles 21 having a particle diameter larger than that of the first inorganic insulating particles 20. Therefore, since the inorganic insulating material has a smaller coefficient of thermal expansion than the resin material, the first inorganic insulating layer 16 has a smaller coefficient of thermal expansion. As a result, the first inorganic insulating layer 16 can reduce the amount of thermal expansion of the first resin layer 15.

Since the inorganic insulating material has a higher Young's modulus than the resin material, the Young's modulus of the first inorganic insulating layer 16 is large. As a result, the first inorganic insulating layer 16 can suppress deformation due to the thermal expansion of the first resin layer 15, and can reduce the thermal expansion amount of the first resin layer 15.

  Further, as shown in FIGS. 2 and 3, the plurality of first inorganic insulating particles 20 are connected to each other, and the plurality of first inorganic insulating particles 20 and the second inorganic insulating particles 21 are also connected to each other. As a result, since the plurality of first inorganic insulating particles 20 and the plurality of first inorganic insulating particles 20 and the second inorganic insulating particles 21 are bound to each other, the Young's modulus of the first inorganic insulating layer 16 is increased. As a result, the first inorganic insulating layer 16 can more effectively suppress deformation due to the thermal expansion of the first resin layer 15.

  Further, as shown in FIG. 3, since the plurality of first inorganic insulating particles 20 or between the plurality of first inorganic insulating particles 20 and the second inorganic insulating particles 21 are connected to each other, A gap G surrounded by a plurality of first inorganic insulating particles 20 and second inorganic insulating particles 21 is formed in the first inorganic insulating layer 16, and the first resin portion 18 of the first resin layer 15 is formed in the gap G. Part of it is filled. As a result, the anchor effect improves the adhesive strength between the first inorganic insulating layer 16 and the first resin layer 15, so that the first inorganic insulating layer 16 favorably reduces the thermal expansion amount of the first resin layer 15. can do.

  Therefore, the first inorganic insulating layer 16 can reduce the thermal expansion of the first resin layer 15 and deformation due to the thermal expansion, and consequently the thermal expansion coefficient of the first insulating layer 9 can be reduced.

  The volume ratio (volume%) including the first inorganic insulating particles 20 and the second inorganic insulating particles 21 in the first inorganic insulating layer 16 is set to, for example, 62 volume% or more and 75 volume% or less. The volume ratio (volume%) of the first inorganic insulating particles 20 is set to, for example, 20 volume% to 90 volume%, and the volume ratio (volume%) of the second inorganic insulating particles 21 is 10 volume% to 80 volume%. It is set to not more than volume%. In addition, the volume ratio (volume%) of the 1st inorganic insulating particle 20 and the 2nd inorganic insulating particle 21 is measured similarly to the filler particle 19a.

  The volume ratio (volume%) of the gap G is set to, for example, 25 volume% or more and 38 volume% or less. And the volume ratio of a part of resin material of the 1st resin layer 15 in the gap | interval G is set to 99.5 volume% or more and 100 volume% or less, for example. The width of the gap G is set to 10 nm or more and 300 nm or less. The volume ratio of the gap G is measured in the same manner as the filler particles 19a. The width of the gap G is determined by first scanning a cross section exposed by polishing the first inorganic insulating layer 16 with a scanning electron microscope or a transmission electron microscope. Observe and photograph a cross section enlarged so as to include a gap G of 20 or more and 50 or less in number, and calculate an average value of the maximum diameters of the gaps G in the enlarged cross section. Measured by considering the width of.

(First inorganic insulating particles)
The first inorganic insulating particles 20 are made of an inorganic insulating material such as silicon oxide, aluminum oxide, magnesium oxide, or calcium oxide, for example. Among these, it is desirable to use silicon oxide. The first inorganic insulating particles 20 are preferably made of an amorphous material. By making the first inorganic insulating particles 20 amorphous, the anisotropy of the coefficient of thermal expansion due to the crystal structure can be reduced, and the occurrence of cracks in the first inorganic insulating layer 16 can be reduced.

  The average particle diameter of the first inorganic insulating particles 20 is set to, for example, 3 nm or more and 110 nm or less, and is smaller than the lower limit value of the wavelength of visible light. In addition, the wavelength of visible light refers to that whose wavelength range is 360 nm or more and 830 nm or less according to JIS Z8120-2001, and the lower limit value of visible light means 360 nm. Moreover, the average particle diameter of the 1st inorganic insulating particle 20 is measured similarly to the filler particle 19a.

(Second inorganic insulating particles)
The second inorganic insulating particle 21 is made of, for example, an inorganic insulating material such as silicon oxide, aluminum oxide, magnesium oxide, or calcium oxide. From the viewpoint of the connection strength between the first inorganic insulating particle 20 and the second inorganic insulating particle 21, It is desirable that the first inorganic insulating particle 20 is made of the same material.

  The second inorganic insulating particles 21 are preferably made of an amorphous material. As a result, the occurrence of cracks in the second inorganic insulating layer 23 due to the crystal structure of the second inorganic insulating particles 21 can be reduced.

  The average particle diameter of the second inorganic insulating particles 21 is set to, for example, not less than 0.5 μm and not more than 5 μm, and is larger than the lower limit value of the wavelength of visible light. In addition, the average particle diameter of the 2nd inorganic insulating particle 21 is measured similarly to the filler particle 19a.

(Surface resin layer)
The surface resin layer 17 is a resin layer disposed on the surface of the first insulating layer 9 and improves, for example, the adhesive strength between the first insulating layer 9 and the first conductive layer 10. The surface resin layer 17 is made of a resin material such as epoxy resin, bismaleimide triazine resin, cyanate resin, polyimide resin or polyamide resin.

  The thickness of the surface resin layer 17 is set to, for example, 0.5 μm or more and 5 μm or less. The thickness of the surface resin layer 17 is measured in the same manner as the light emitting element 2.

  Here, since the thickness of the surface resin layer 17 is set to 5 μm or less, the surface resin layer 17 can satisfactorily transmit visible light that has reached the upper surface of the wiring board 3 for light emitting element. Further, since the thickness of the surface resin layer 17 is set as thin as 5 μm or less, the visible light transmittance of the surface resin layer 17 is 80% or more. As a result, the absorption of visible light by the filler particles 19b is reduced, and the visible light reaches the first inorganic insulating layer 12 disposed on the lower surface of the surface resin layer 17 satisfactorily.

  Further, the surface resin layer 17 may include filler particles 19b. In that case, the volume ratio (volume%) of the filler particles 19b in the surface resin layer 17 is set to, for example, 2 volume% or more and 3 volume% or less. Here, since the volume ratio (volume%) of the filler particles 19b is set to be as small as 3 volume% or less, the surface resin layer 17 transmits the visible light that has reached the upper surface of the light-emitting element wiring substrate 3 satisfactorily. can do. The average particle diameter of the filler particles 19b included in the surface adhesive layer 16 is desirably set smaller than the lower limit value of the wavelength of visible light. As a result, the surface resin layer 17 can transmit visible light satisfactorily.

(First conductive layer)
The first conductive layer 10 is electrically connected to the light emitting element 2 via a bonding wire or the like, and electrically connected to an external circuit board (not shown) and a conductive metal wire. To be connected. The first conductive layer 10 is made of a conductive material such as copper, silver, gold, or aluminum.

  The thickness of the first conductive layer 10 is set to 3 μm or more and 20 μm or less, for example. The Young's modulus of the first conductive layer 10 is set to, for example, 50 GPa or more and 200 GPa or less. And the thermal expansion coefficient to the plane direction (XY plane direction) of the 1st conductive layer 10 is set to 16 ppm / degrees C or more and 18 ppm / degrees C or less, for example. The thickness, Young's modulus, and thermal expansion coefficient of the first conductive layer 10 are measured in the same manner as the first insulating layer 9.

(Second insulation layer)
The second insulating layer 11 is a main part of the light emitting element wiring substrate 3, and includes a second resin layer 22, a second inorganic insulating layer 23 laminated on the upper surface of the second resin layer 22, and a second layer. And a surface resin layer 17 laminated on the upper surface of the inorganic insulating layer 23.

  The thickness of the second insulating layer 11 is set to, for example, 20 μm or more and 100 μm or less. The Young's modulus of the second insulating layer 11 is set to 20 GPa or more and 45 GPa or less, for example. And the thermal expansion coefficient to the plane direction (XY plane direction) of the 2nd insulating layer 11 is set to 13 ppm / degrees C or more and 19 ppm / degrees C or less, for example. The thickness, Young's modulus, and thermal expansion coefficient of the second insulating layer 11 are measured in the same manner as the first insulating layer 9.

(Second resin layer)
The second resin layer 22 is a main part of the second insulating layer 11 and has the same configuration as the first resin layer 15.

(Second inorganic insulating layer)
The second inorganic insulating layer 23 improves the Young's modulus of the second insulating layer 11 and has the same configuration as the first inorganic insulating layer 16.

(Second conductive layer)
The second conductive layer 12 functions as a signal wiring, a ground wiring, or a power supply wiring, and has the same configuration as the first conductive layer 10.

(Via conductor)
The via conductor 13 penetrates the first insulating layer 9 or the second insulating layer 11 in the thickness direction (Z direction), and electrically connects the first conductive layer 10 and the second conductive layer 12. For example, made of a conductive material such as copper, silver, gold or aluminum.

  The Young's modulus of the via conductor 13 is set to, for example, 50 GPa or more and 200 GPa or less. The thermal expansion coefficient in the planar direction (XY planar direction) of the via conductor 19 is set to, for example, 16 ppm / ° C. or more and 18 ppm / ° C. or less. Note that the Young's modulus and thermal expansion coefficient of the via conductor 13 are measured in the same manner as the first inorganic insulating layer 16.

(Metal plate)
The metal plate 14 dissipates heat generated by the light emitting element 2, and is made of, for example, copper, aluminum, iron, nickel, cobalt, or an alloy thereof. The thickness of the metal plate 14 is set to 0.05 mm or more and 2 mm or less, for example. The Young's modulus of the metal plate 14 is set to, for example, 50 GPa or more and 200 GPa or less. The coefficient of thermal expansion in the plane direction (XY plane direction) of the metal plate 14 is set to, for example, 1 ppm / ° C. or more and 20 ppm / ° C. or less. The thermal conductivity of the metal plate 14 is set to, for example, 50 W / m · K or more and 430 W / m · K or less.

  The thickness, thermal expansion coefficient, and thermal conductivity of the metal plate 14 are measured in the same manner as the first insulating layer 9. The Young's modulus of the metal plate 14 is, for example, per unit cross-sectional area obtained by cutting a rectangular test piece from the metal plate 14 using a dicing machine, a knife, or a saw, and measuring the test piece with a tensile tester. It can be measured by dividing the tensile stress by the amount of elongation of the test piece.

  By the way, as described above, the particle diameter of the first inorganic insulating particles 20 is smaller than the wavelength of visible light. Therefore, visible light is not easily reflected by the first inorganic insulating particles 20, and visible light that has entered the first inorganic insulating layer 16 from the upper surface of the first inorganic insulating layer 16 is satisfactorily reflected by the second inorganic insulating particles 21. Will be reached. When the visible light reaches the spherical second inorganic insulating particles 21 that are larger than the wavelength of visible light, it is likely to be reflected (recursively reflected) in the same direction as the incident direction. That is, when the visible light reaches the outer surface of the second inorganic insulating particle 21 having a wavelength longer than that of the visible light, the second light generally made of silicon oxide, aluminum oxide, magnesium oxide, calcium oxide, or the like having high translucency. It enters the inorganic insulating particles 21. Then, the visible light that has reached the inner surface of the second inorganic insulating particle 21 due to the difference in refractive index between the inner and outer sides of the second inorganic insulating particle 21 is reflected by the inner surface of the second inorganic insulating particle 21, and 2 Go out of the inorganic insulating particles 21. At this time, the visible light is refracted when entering the second inorganic insulating particles 21, reflected by the inner surface of the second inorganic insulating particles 21, and refracted when going out of the second inorganic insulating particles 21. The visible light is reflected in the same direction as the incident direction with respect to the second inorganic insulating particles 21, and retroreflection occurs.

  As a result, the visible light reaching the upper surface of the light emitting element wiring substrate 3 is again moved upward by the first inorganic insulating layer 16 included in the first insulating layer 9 constituting the upper surface of the light emitting element wiring substrate 3. The brightness of the light emitting device can be improved.

  Further, as described above, the first inorganic insulating layer 16 includes the plurality of first inorganic insulating particles 20 and the plurality of second inorganic insulating particles 21 as main components. As a result, it is possible to reduce the absorption of visible light by the first resin portion 18 and to improve the brightness of the light emitting device as compared with an insulating layer mainly composed of a conventional resin material. it can.

  As described above, the gap G is formed in the first inorganic insulating layer 16, and the width of the gap G is preferably smaller than the lower limit value of the wavelength of visible light. As a result, the width of the first resin portion 18 filled in the gap G is also smaller than the lower limit value of the wavelength of visible light, so that the visible light that has entered the first inorganic insulation 15 18, the second inorganic insulating particles 21 can be satisfactorily reached, and thus the brightness of the light emitting device can be improved.

  Moreover, it is preferable that the 1st inorganic insulating particle 20 consists of a silicon oxide, aluminum oxide, magnesium oxide, or calcium oxide with high translucency generally. As a result, visible light that has entered the first inorganic insulating layer 16 from the upper surface of the first inorganic insulating layer 16 can reach the second inorganic insulating particles 21 more satisfactorily.

  The filler particles 19a contained in the first resin layer 15 are preferably made of titanium oxide. As a result, since titanium oxide generally has a high reflectance, visible light transmitted through the first inorganic insulating layer 16 is reflected by the outer surface of the filler particles 19a included in the first resin layer 15 to emit light. It is possible to reduce the absorption of visible light that has entered the element wiring board 3, thereby improving the brightness of the light emitting device.

  Further, it is desirable that many filler particles 19 a included in the first resin layer 15 are located on the first inorganic insulating layer 16 side of the first resin layer 15. As a result, the visible light transmitted through the first inorganic insulating layer 16 is favorably reflected by the filler particles 19a included in the first resin layer 15, so that the visible light that has entered the light emitting element wiring board 3 is reflected. Absorption is reduced, and as a result, the brightness of the light-emitting device can be improved.

  In addition, when the 1st resin layer 15 is divided into two so that thickness may become equal, the one near the 1st inorganic insulating layer 16 is made into the 1st field, and the one far from the 1st inorganic insulating layer 16 is made into the 2nd field Furthermore, for example, 55% or more and 70% or more of the filler particles 19a are located in the first region, and for example, 30% or more and 45% or less are located in the second region.

  The lower surface of the metal plate 14 is desirably exposed to the atmosphere. As a result, the heat generated by the light emitting element 2 can be released well.

  Further, from the viewpoint of thermal conductivity, the metal plate 14 is preferably made of copper. As a result, the heat generated by the light emitting element 2 can be released well.

  The thermal expansion coefficient of the metal plate 14 is desirably smaller than that of the first resin layer 15 and larger than that of the first inorganic insulating layer 16. As a result, the difference in coefficient of thermal expansion between the metal plate 14 and the first insulating layer 9 can be reduced, and distortion of the light emitting element wiring substrate 3 can be reduced.

  In addition, when the metal plate 14 consists of copper, it is desirable that the 1st inorganic insulating particle 20 consists of silicon oxide from a viewpoint of a thermal expansion coefficient. As a result, the difference in coefficient of thermal expansion between the metal plate 14 and the first insulating layer 9 can be reduced satisfactorily.

  In addition, the thermal expansion coefficient of the metal plate 14 is preferably smaller than that of the second resin layer 22 and larger than that of the second inorganic insulating layer 23. As a result, the difference in coefficient of thermal expansion between the second insulating layer 11 and the metal plate 14 can be reduced, and the second resin layer 22 and the metal plate 14 can be favorably reduced.

(Production of light emitting device)
Next, the manufacturing method of the light-emitting device 1 mentioned above is demonstrated, referring FIG.

(Production of laminated sheet)
(1) An inorganic insulating sol having a solid content including the first inorganic insulating particles 20 and the second inorganic insulating particles 21 and a solvent in which the solid content is dispersed is prepared.

  The inorganic insulating sol includes, for example, a solid content of 10% to 50% by volume and a solvent of 50% to 90% by volume. Further, the solid content of the inorganic insulating sol includes, for example, the first inorganic insulating particles 20 by 20% by volume to 90% by volume and the second inorganic insulating particles 21 by 10% by volume to 80% by volume.

  In addition, the 1st inorganic insulating particle 20 can be produced by refine | purifying silicate compounds, such as sodium silicate aqueous solution (water glass), and depositing a silicon oxide chemically, for example. In this case, since the first inorganic insulating particles 20 can be produced under a low temperature condition, the first inorganic insulating particles 20 in an amorphous state can be produced.

  On the other hand, if the second inorganic insulating particles 21 are made of silicon oxide, for example, a solution obtained by purifying a silicate compound such as an aqueous sodium silicate solution (water glass) and chemically depositing silicon oxide is used as a flame. It can be produced by spraying in and heating to 800 ° C. or higher and 1500 ° C. or lower while reducing the formation of aggregates.

  Moreover, it is desirable that the heating time for producing the second inorganic insulating particles 21 is set to 1 second or more and 180 seconds or less. As a result, by shortening the heating time, the crystallization of the second inorganic insulating particles 21 can be reduced and the amorphous state can be maintained even when heated to 800 ° C. or higher and 1500 ° C. or lower.

On the other hand, the solvent contained in the inorganic insulating sol is, for example, methanol, isopropanol, n-butanol, ethylene glycol, ethylene glycol monopropyl ether, methyl ethyl ketone, methyl isobutyl ketone, xylene, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethyl An organic solvent containing acetamide and / or a mixture of two or more selected from these may be used.

  (2) A support sheet 24 made of a resin material or a metal material having a surface resin layer 17 disposed on one main surface is prepared, and an inorganic insulating sol is applied on one main surface of the surface resin layer 17.

  The inorganic insulating sol can be applied using, for example, a dispenser, a bar coater, a die coater, or screen printing. At this time, as described above, since the solid content of the inorganic insulating sol is set to 50% by volume or less, the viscosity of the inorganic insulating sol is set low, and the flatness of the coated inorganic insulating sol can be increased. it can.

  In addition, if the surface resin layer 17 contains the filler particles 19b at a ratio of 2% by volume or more and 3% by volume or less, for example, the support sheet 24 can be peeled off at a later time.

  (3) The inorganic insulating sol is dried to evaporate the solvent.

  The inorganic insulating sol is dried by, for example, heating and air drying. The drying temperature is set to, for example, 20 ° C. or higher and lower than the boiling point of the solvent (the boiling point of the lowest boiling solvent when two or more solvents are mixed), and the drying time is, for example, 20 seconds to 30 minutes. Set to As a result, the boiling of the solvent is reduced, the extrusion of the first inorganic insulating particles 20 and the second inorganic insulating particles 21 due to the pressure of bubbles generated during the boiling is reduced, and the distribution of the particles is made more uniform. Is possible.

  (4) The solid content of the remaining inorganic insulating sol is heated so that the plurality of first inorganic insulating particles 20 and the first inorganic insulating particles 20 and the second inorganic insulating particles 21 are partially connected to each other. The insulating layer 23 is produced.

  Here, the inorganic insulating sol has the first inorganic insulating particles 20 whose average particle diameter is set to be minute. As a result, even if the heating temperature of the inorganic insulating sol is relatively low, for example, lower than the crystallization start temperature of the first inorganic insulating particles 20 and the second inorganic insulating particles 21, the first inorganic insulating particles 20 are firmly bonded. Can be connected to.

  As for the heating of the inorganic insulating sol, the temperature is preferably set to, for example, 100 ° C. or more and less than 300 ° C., and the time is preferably set to, for example, 0.5 hours or more and 24 hours or less. Moreover, it is desirable that the heating temperature of the inorganic insulating sol is set to be lower than the crystallization start temperature of the first inorganic insulating particles 20 and the second inorganic insulating particles 21. As a result, the crystallized particles can be prevented from shrinking due to the phase transition, and the occurrence of cracks in the second inorganic insulating layer 23 can be reduced.

  Furthermore, by heating at such a low temperature in this way, the first inorganic insulating particles 20 and the first inorganic insulating particles 20 and the first inorganic insulating particles 20 and the first inorganic insulating particles 20 and the second inorganic insulating particles 21 maintain the shape of the particles. 2 The inorganic insulating particles 21 can be connected only in the proximity region. As a result, the first inorganic insulating particles 20 and the first inorganic insulating particles 20 and the second inorganic insulating particles 21 can be connected to each other. As a result, the open pore gap G can be easily formed between the first inorganic insulating particles 20. Can be formed.

  (5) A resin precursor 25 including an uncured resin material and filler particles 19a coated with the resin material is prepared. Next, as shown in FIG. 4A, a resin precursor 25 is laminated on the main surface of the second inorganic insulating layer 23 opposite to the surface resin layer 17, and the support sheet 24, the surface resin layer 17, the second A laminated sheet 26 including the inorganic insulating layer 23 and the resin precursor 25 is produced.

(Preparation of wiring board for light emitting element)
(6) The metal plate 14 is prepared, and the laminate sheet 26 is laminated on the metal plate 14 so that the resin precursor 25 of the laminate sheet 26 is disposed on the main surface of the metal plate 14. Next, the resin precursor 25 is cured by heating and pressurizing the laminated sheet 26 and the metal plate 14, the resin precursor 25 is used as the second resin layer 22, the support sheet 24 is peeled off, and the second insulating layer 11 is formed. It is arranged on the main surface of the metal plate 14.

  The heating and pressing of the laminated sheet 26 and the metal plate 14 are performed by heating and pressing in the vertical direction, so that an uncured resin material enters a part of the gap G of the second inorganic insulating layer 23, and the second inorganic The insulating layer 23 and the resin precursor 25 are bonded. In addition, uncured is the state of A-stage or B-stage according to ISO472: 1999.

  The heating and pressing of the laminated sheet 26 and the metal plate 14 are performed at a temperature not lower than the curing start temperature of the resin precursor 25 and lower than the thermal decomposition temperature of the resin precursor 25. Specifically, the heating temperature is set, for example, to 150 ° C. or more and 250 ° C. or less, the pressure is set, for example, to 2 MPa or more and 3 MPa or less, and the time is set, for example, 0.5 hours or more and 2 hours or less. The curing start temperature is a temperature at which the resin becomes a C-stage according to ISO 472: 1999.

  Here, the average particle diameter of the filler particles 19 a contained in the resin precursor 25 is preferably larger than the width of the gap G. As a result, the uncured second resin material of the resin precursor 25 enters the gap G of the first inorganic insulating layer 16 so that the plurality of filler particles 19 a are filtered on the surface of the first inorganic insulating layer 16. The first resin layer 15 that aggregates and has a larger volume ratio of the filler particles 19 a in a region closer to the first inorganic insulating layer 16 than in a region farther from the first inorganic insulating layer 16 can be formed. Therefore, the first resin layer 15 having a small coefficient of thermal expansion on the first inorganic insulating layer 16 side can be easily produced, and as a result, the production efficiency can be improved.

  The volume ratio of the filler particles 19 a in the resin precursor 25 is set to, for example, 10 volume% or more and 55 volume% or less, and is formed on one main surface of the second inorganic insulating layer 23 after the formation of the second resin layer 22. The volume ratio of the filler particles 19a in the second resin layer 22 is set to, for example, 10% by volume or more and 70% by volume or less.

  (7) The second conductive layer 12 is formed on the upper surface of the second insulating layer 11.

  The second conductive layer 12 is formed by depositing a conductive material using, for example, an electroless plating method, an electroplating method, a vapor deposition method, a CVD method, or a sputtering method, and then using, for example, a photolithography technique, an etching method, or the like. It can be formed by patterning the conductive material deposited.

  (8) As shown in FIG. 4C, the steps (1) to (6) are repeated to dry the inorganic insulating sol and dry the first inorganic insulating layer 16 and the resin precursor 25. A first insulating layer 9 including the cured first resin layer 15 is formed on the upper surfaces of the second insulating layer 11 and the second conductive layer 12.

  (9) The via conductor 13 that penetrates the first insulating layer 9 in the thickness direction (Z direction) is formed, and the first conductive layer 10 that is electrically connected to the via conductor 13 is formed on the first insulating layer 9.

The via conductor 13 is formed by first forming a via hole in the second insulating layer 11 using, for example, a YAG laser device or a carbon dioxide gas laser device. Next, for example, by filling the via hole V with a conductive material using electroless plating, vapor deposition, CVD, or sputtering,
A via conductor 13 is formed.

(Mounting of light emitting elements)
(9) As shown in FIG. 4D, after the light emitting element 2 is mounted on the upper surface of the first insulating layer 9, the light emitting element 2 and the first conductive layer 10 are connected by a bonding wire. Next, the reflection plate 4 and the cover member 5 are arranged around the light emitting element 2 so as to cover the reflection plate 4.

  As described above, the light emitting device 1 in which the light emitting element 2 is mounted on the upper surface of the light emitting element wiring substrate 3 is manufactured.

Second Embodiment
(Light emitting device)
Next, a second example (second embodiment) of the embodiment of the light-emitting element wiring board and the light-emitting device of the present invention will be described in detail with reference to FIG. In addition, description is abbreviate | omitted regarding the structure similar to 1st Embodiment mentioned above.

  As shown in FIG. 5, the light-emitting element wiring substrate 3 of the second embodiment is different from that of the first embodiment, and the first inorganic insulating layer 16 is located at the uppermost layer of the first insulating layer 9 and is used for the light-emitting element. The upper surface of the wiring board 3 is configured. As a result, the visible light that has reached the upper surface of the wiring board 3 for the light emitting element can enter the first inorganic insulating layer 16 well, and more visible light can be reflected. Can be improved.

  Since the first inorganic insulating layer 16 is positioned at the uppermost layer of the first insulating layer 9, visible light reaching the upper surface of the first insulating layer 9 reaches the upper surface of the first inorganic insulating layer 16. Become. That is, in the first insulating layer 9, the upper surface of the first inorganic insulating layer 16 is naturally positioned at “depth at which visible light reaches”.

(Production of light emitting device)
Next, the manufacturing method of the light-emitting device 1 of 2nd Embodiment mentioned above is demonstrated. In addition, description is abbreviate | omitted regarding the method similar to 1st Embodiment mentioned above.

  In the step (2) described above, the inorganic insulating sol is directly applied on the main surface of the support sheet 24, and the inorganic insulating sol is used as the second inorganic insulating layer 23, and then the resin is formed on the main surface opposite to the support sheet 24. The precursor 25 is laminated | stacked and the laminated sheet 26 containing the support sheet 24, the surface resin layer 17, the 2nd inorganic insulating layer 23, and the resin precursor 25 is produced. And the light-emitting device 1 is producible with the process similar to 1st Embodiment mentioned above.

<Third Embodiment>
(Light emitting device)
Next, a third example (third embodiment) of the embodiment of the wiring board for light emitting element and the light emitting device of the present invention will be described in detail with reference to FIG. In addition, description is abbreviate | omitted regarding the structure similar to 1st Embodiment mentioned above.

  As shown in FIG. 6, unlike the first embodiment, the light emitting element wiring substrate 3 of the second embodiment includes a first through hole T1 that houses the light emitting element 2 and penetrates the first insulating layer 9. And a second through hole T2 penetrating the second insulating layer 11, and a recess D having the metal plate 14 as a bottom surface is formed.

  Thus, by forming the recess D, the light emitting element 2 accommodated in the recess D is mounted on the upper surface of the metal plate 14. As a result, since the metal material has higher thermal conductivity than the resin material and the inorganic insulating material, the heat generated by the light-emitting element 2 can be released well, and the light-emitting element caused by the temperature rise of the light-emitting element 2 2 can prevent a decrease in luminous efficiency and a decrease in lifetime.

  In addition, the thermal conductivity of the first inorganic insulating layer 16 and the second inorganic insulating layer 23 is preferably larger than the thermal conductivity of the first resin layer 15 and the second resin layer 22. As a result, the light emitting element 2 accommodated in the first through hole T1 and the second through hole T2 is surrounded by the first inorganic insulating layer 16 and the second inorganic insulating layer 23. The emitted heat can be released well.

  In addition, the inner diameter of the first inorganic insulating layer 16 of the first through hole T1 is desirably smaller than the inner diameter of the first resin layer 15. As a result, the distance between the first inorganic insulating layer 16 and the light emitting element 2 in the first through hole T1 is reduced, and among the visible light reaching the upper surface of the light emitting element wiring substrate 3, the light emitting element 2; Visible light enters between the inner wall of the first through-hole T1 and is absorbed by the inner wall of the first through-hole T1 and the like, and loss of visible light can be reduced.

  Further, the thickness of the first inorganic insulating layer 16 is desirably larger than the thickness of the first resin layer 15. As a result, the area from which the heat generated by the light emitting element 2 is released becomes large, and the heat generated by the light emitting element 2 can be released well.

  Moreover, it is desirable that the inner diameter of the second through hole T2 in the second inorganic insulating layer 23 is smaller than the inner diameter of the second resin layer 22. As a result, the distance between the second inorganic insulating layer 23 and the light emitting element 2 in the second through hole T2 is reduced, and the heat generated by the light emitting element 2 can be released well.

  The thickness of the second inorganic insulating layer 23 is desirably larger than the thickness of the second resin layer 22. As a result, the area from which the heat generated by the light emitting element 2 is released becomes large, and the heat generated by the light emitting element 2 can be released well.

  In addition, the light emitting portion 7 of the light emitting element 2 is desirably located above the upper surface of the first inorganic insulating layer 16. As a result, the visible light emitted from the light emitting element 2 is reflected by the first inorganic insulating layer 16 constituting the inner wall surface of the first through hole T1, and the loss of visible light in the first through hole T1 is reduced. Can do.

  Moreover, it is desirable that the light emitting portion 7 of the light emitting element 2 is located above the opening of the first through hole T1. As a result, visible light emitted from the light emitting element 2 can be reduced from being absorbed by the first resin layer 15 and the like on the inner wall surface of the first through hole T1.

(Production of light emitting device)
Next, a method for manufacturing the light emitting device 1 according to the third embodiment will be described. In addition, description is abbreviate | omitted regarding the method similar to 1st Embodiment mentioned above.

  After the step (8) described above, the first through hole T1 penetrating the first insulating layer 9 and the second through hole T2 penetrating the second insulating layer 11 for accommodating the light emitting element 2 are formed.

  The first through hole T1 and the second through hole T2 can be formed by, for example, laser processing, punching processing, or sand blast processing.

  In addition, after forming the first through hole T1 and the second through hole T2, it is desirable to subject the inner peripheral surfaces of the first through hole T1 and the second through hole T2 to desmear treatment.

  Specifically, the desmear treatment is performed by impregnating the permanganic acid solution with the wiring board 3 for a light emitting element within 5 minutes to 10 minutes, for example. In this step, since the permanganic acid solution dissolves the resin material, not only the inside of the first through hole T1 and the second through hole T2 is desmeared well, but also the first resin layer 15 and the second resin layer 22 A part can be melted. As a result, the inner diameter of the first through hole T1 in the first inorganic insulating layer 16 can be made smaller than the inner diameter of the first resin layer 15, and the inner diameter of the second through hole T2 in the second inorganic insulating layer 23 can be reduced to the second. The inner diameter of the resin layer 22 can be made smaller.

  The present invention is not limited to the above-described embodiment, and various changes, improvements, combinations, and the like can be made without departing from the spirit of the present invention.

  Moreover, although the embodiment of the present invention described above includes the metal plate 14, the metal plate 14 may not be included.

  Moreover, although the embodiment of the present invention described above includes only one second inorganic insulating layer 23, it may include a plurality of second inorganic insulating layers 23.

  In the embodiment of the present invention described above, the second inorganic insulating layer 23 includes the second inorganic insulating particles 21, but the second inorganic insulating layer 23 may not include the second inorganic insulating particles 21. .

  Further, in the above-described embodiment of the present invention, nothing is filled in the space surrounded by the light emitting element wiring substrate 3, the reflector 4 and the cover member 5, but for example, a resin material is filled together with a fluorescent material. It doesn't matter.

  Moreover, although 2nd Embodiment of this invention mentioned above formed 1st through-hole T1 and 2nd through-hole T2, you may form only 1st through-hole T1. In that case, the light emitting element 2 is mounted on the upper surface of the second insulating layer 11.

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Light-emitting element 3 Light-emitting-element wiring board 4 Reflector 5 Cover member 6 Base part 7 Light-emitting part 8 Lens part 9 1st insulating layer 10 1st conductive layer 11 2nd insulating layer 12 2nd conductive layer 13 Via conductor DESCRIPTION OF SYMBOLS 14 Metal plate 15 1st resin layer 16 1st inorganic insulating layer 17 Surface resin layer 18 1st resin part 19a, 19b Filler particle 20 1st inorganic insulating particle 21 2nd inorganic insulating particle 22 2nd resin layer 23 2nd inorganic insulation Layer 24 Support sheet 25 Resin precursor 26 Laminated sheet G Gap T1 First through hole T2 Second through hole D Recess

Claims (11)

A wiring board for a light emitting element on which a light emitting element having a light emitting portion that emits light upward is mounted,
A first insulating layer comprising a first resin layer and a first inorganic insulating layer laminated on the first resin layer, the upper surface forming a first resin layer;
The first inorganic insulating layer has a particle diameter smaller than the lower limit value of the wavelength of visible light, and has a particle diameter smaller than the lower limit value of the wavelength of visible light. A plurality of spherical second inorganic insulating particles surrounded by the plurality of first inorganic insulating particles, and surrounded by the plurality of first inorganic insulating particles and the plurality of second inorganic insulating particles. A wiring board for a light emitting element, wherein a gap is formed and is located at a depth at which visible light entering the inside of the first insulating layer reaches from the upper surface of the first insulating layer. In the wiring board for light emitting elements according to claim 1,
The first inorganic insulating layer constitutes an upper surface of the light emitting element wiring substrate. In the wiring board for light emitting elements of Claim 1 or Claim 2,
A wiring board for a light emitting element, wherein the first insulating layer has a first through hole in which the light emitting element is accommodated. In the wiring board for light emitting elements according to claim 3,
The light-emitting element wiring board, wherein the first through hole has an inner diameter smaller than that of the first resin layer in the first inorganic insulating layer. In the wiring board for light emitting elements according to claim 3,
A second insulating layer disposed on a lower surface of the first insulating layer;
The second insulating layer includes a second resin layer and a second inorganic insulating layer that is laminated on the second resin layer and includes a plurality of the first inorganic insulating particles connected to each other. A light-emitting element wiring board comprising: a second through-hole that is connected to the first through-hole and that houses the light-emitting element. In the wiring board for light emitting elements according to claim 1,
A metal plate disposed under the first insulating layer;
The wiring board for a light-emitting element, wherein a thermal expansion coefficient of the metal plate is larger than a thermal expansion coefficient of the first inorganic insulating layer and smaller than a thermal expansion coefficient of the first resin layer. A wiring board for a light emitting element on which a light emitting element having a light emitting portion that emits light upward is mounted,
A first insulating layer comprising a first resin layer, a first inorganic insulating layer laminated on the upper surface of the first resin layer, and a surface resin layer laminated on the upper surface of the first inorganic insulating layer. With layers,
The first inorganic insulating layer has a particle diameter smaller than the lower limit value of the wavelength of visible light, and has a particle diameter smaller than the lower limit value of the wavelength of visible light. A plurality of spherical second inorganic insulating particles surrounded by the plurality of first inorganic insulating particles, and surrounded by the plurality of first inorganic insulating particles and the plurality of second inorganic insulating particles. Gaps are formed,
The thickness of the said surface resin layer is set to 5 micrometers or less, The wiring board for light emitting elements characterized by the above-mentioned. A light-emitting device comprising: the light-emitting element wiring board according to claim 1, claim 2, claim 6 or claim 7; and a light-emitting element mounted on an upper surface of the first insulating layer.   A light emitting device comprising: the light emitting element wiring board according to claim 3; and a light emitting element housed in the first through hole.   A light-emitting device comprising: the light-emitting element wiring board according to claim 5; and a light-emitting element housed in the first through hole and the second through hole. The light-emitting device according to claim 9 or 10,
The light emitting device is characterized in that a light emitting portion is positioned above an opening of the first through hole.

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