WO2012036132A1 - Substrate for mounting light-emitting element, and light-emitting device - Google Patents
Substrate for mounting light-emitting element, and light-emitting device Download PDFInfo
- Publication number
- WO2012036132A1 WO2012036132A1 PCT/JP2011/070756 JP2011070756W WO2012036132A1 WO 2012036132 A1 WO2012036132 A1 WO 2012036132A1 JP 2011070756 W JP2011070756 W JP 2011070756W WO 2012036132 A1 WO2012036132 A1 WO 2012036132A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- emitting element
- substrate
- light emitting
- glass
- powder
- Prior art date
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Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/64—Heat extraction or cooling elements
- H01L33/641—Heat extraction or cooling elements characterized by the materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/481—Disposition
- H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
- H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
- H01L2224/48225—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
- H01L2224/48227—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation connecting the wire to a bond pad of the item
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
- H01L2924/181—Encapsulation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/64—Heat extraction or cooling elements
- H01L33/642—Heat extraction or cooling elements characterized by the shape
Definitions
- the present invention relates to a light-emitting element mounting substrate and a light-emitting device, and more particularly, to a light-emitting element substrate having low thermal resistance and high heat dissipation, and a light-emitting device using the same.
- LED light emitting diode
- an alumina substrate is used as a substrate for mounting a light emitting element.
- an alumina substrate has a low light reflectivity and transmits light incident on the substrate, so that a silver reflection film is formed on the substrate surface.
- a protective layer made of glass or the like it is necessary to provide a protective layer made of glass or the like on the surface of the silver reflecting film in order to prevent the reflectance from being reduced due to oxidation or sulfuration of the silver reflecting film, and the light extraction efficiency can be sufficiently increased. could not. That is, when a silver reflective film is provided on a substrate, the light extraction efficiency is higher when the area of the silver reflective film is as large as possible.
- a low-temperature co-fired ceramic substrate (hereinafter referred to as an LTCC substrate) is used as a light-emitting element mounting substrate having a higher reflectance than a ceramic substrate such as an alumina substrate.
- the LTCC substrate is made of a sintered body of ceramic powder such as alumina powder and glass, and has a large refractive index difference between the glass and ceramic, and a large proportion of the interface between the two facing the light incident direction. Since the particle size of the powder is larger than the wavelength used, a high reflectance can be obtained. Therefore, the light from the light emitting element can be used efficiently, and as a result, the heat generation amount can be reduced. Moreover, since it consists of an inorganic oxide with little deterioration by a light source, a color tone is stabilized over a long period of time.
- ceramic powder for example, zirconia powder
- alumina powder having a refractive index higher than that of alumina
- a die bond material having a low thermal conductivity (the thermal conductivity of the silicone die bond material is equal to the gap between the substrate surface and the light emitting element) Since a thick layer of 0.1 W / m ⁇ K) is sandwiched, there is a problem that heat dissipation from the light emitting element to the substrate is further reduced.
- the glaze process described in these patent documents is performed in order to accurately form a fine wiring pattern in the manufacture of a substrate for a thermal head of a facsimile or a printer head. It is not something to do.
- the purpose of forming the glass layer on the substrate surface is not to improve heat dissipation but to improve the formation accuracy of the fine wiring pattern.
- the surface roughness is in line with its purpose, and a sufficient effect cannot be obtained in terms of heat dissipation.
- the present invention has been made in order to solve the above-described problem, and the reflectance of the substrate body is improved without providing a reflective film, and the heat dissipation from the mounted light emitting element to the substrate is achieved. It is an object of the present invention to provide an improved light emitting element mounting substrate and a light emitting device having high light emission luminance with excellent light extraction efficiency using such a light emitting element mounting substrate.
- the light emitting element mounting substrate of the present invention is made of an inorganic insulating material and has a mounting surface including a mounting portion on which the light emitting element is mounted, and the mounting surface of the substrate main body covers at least the mounting portion.
- An overcoat layer made of a material mainly composed of glass, and the overcoat layer has a thickness of 3 to 20 times the surface roughness Ra of the mounting surface of the substrate body, The overcoat layer has a surface roughness Ra of 0.15 ⁇ m or less.
- the substrate body is made of a sintered body of a glass ceramic composition containing glass powder and ceramic powder.
- the ceramic powder preferably includes an alumina powder and a ceramic powder having a higher refractive index than alumina.
- the ceramic powder is preferably at least one selected from the group consisting of titania powder, zirconia powder, stabilized zirconia powder, zinc oxide powder, barium titanate powder, and lead titanate powder.
- the glass-based material constituting the overcoat layer has a softening point of 850 ° C. or lower.
- the softening point By setting the softening point to 850 ° C. or lower, firing at 860 ° C. or higher and 880 ° C. or lower can be performed. Therefore, when the substrate body is obtained by firing, an overcoat layer can be formed by simultaneous firing.
- the glass constituting the overcoat layer preferably contains at least SiO 2 and B 2 O 3 and at least one selected from Na 2 O and K 2 O.
- the glass is expressed in terms of mol% on the basis of oxide, SiO 2 62 to 84%, B 2 O 3 10 to 25%, Al 2 O 3 0 to 5%, MgO 0 to 10%, At least one selected from Na 2 O and K 2 O is contained in a total of 1 to 5%, the total content of SiO 2 and Al 2 O 3 is 62 to 84%, and selected from CaO, SrO and BaO
- a borosilicate glass powder having a total content of 5% or less is preferred when it contains at least one kind.
- “to” indicating the numerical range described above is used to mean that the numerical values described before and after it are used as a lower limit value and an upper limit value, and hereinafter “to” Used with meaning.
- the present invention provides a light emitting device comprising the light emitting element mounting substrate of the present invention and a light emitting element mounted on the mounting portion of the light emitting element mounting substrate.
- the mounting portion of the mounting surface of the substrate body made of an inorganic insulating material is made of a material mainly made of glass, and has a thickness 3 to 20 times the surface roughness Ra of the mounting surface.
- An overcoat layer having a thickness is formed, and the surface roughness Ra of the overcoat layer is 0.15 ⁇ m or less and is configured to be extremely smooth, so that the contact area between the overcoat layer and the light emitting element is increased, The thickness of the die bond material having low thermal conductivity interposed between these layers can be reduced. Therefore, the thermal resistance from the light emitting element to the substrate can be reduced, and a light emitting element mounting substrate with improved heat dissipation can be provided. Further, by using this light emitting element mounting substrate, a light emitting device having excellent light extraction efficiency and high light emission luminance can be provided.
- FIG. 2 is a cross-sectional view of the light emitting element mounting substrate shown in FIG. 1 cut along line X-X ′. It is the top view which looked at the green sheet for upper layers used for manufacture of the light emitting element mounting substrate of this invention from the upper surface side. It is the top view which looked at the green sheet for inner layers used for manufacture of the light emitting element mounting substrate of this invention from the upper surface side.
- FIG. 8 is a cross-sectional view of the light emitting device shown in FIG. 7 cut along line Y-Y ′.
- the light emitting element mounting substrate of the present invention is made of an inorganic insulating material, and has a substrate body having a mounting surface as a mounting portion on which the light emitting element is partially mounted, and at least the mounting portion is mounted on the mounting surface of the substrate body.
- An overcoat layer made of a glass-based material (hereinafter sometimes referred to as a glass material) formed so as to cover is provided.
- the overcoat layer has a thickness 3 to 20 times the surface roughness Ra of the mounting surface of the substrate body. Further, the surface roughness Ra of the overcoat layer is 0.15 ⁇ m or less.
- the surface roughness Ra is represented by 3 “Definition and display of defined arithmetic average roughness” of JIS: B0601 (1994).
- Surfcom 1400D model name, manufactured by Tokyo Seimitsu Co., Ltd. Is a value measured by
- an overcoat layer made of a glass material having a thickness 3 to 20 times the surface roughness Ra of the mounting surface is formed on at least the mounting portion of the mounting surface of the substrate body. Since the surface of the formed overcoat layer is extremely smooth with a surface roughness Ra of 0.15 ⁇ m or less, when mounting and mounting a light emitting device such as an LED device on this overcoat layer, the overcoat layer The contact area between the layer and the light-emitting element is increased, and the thickness of the silicone die bond material for joining the light-emitting element interposed between these layers can be greatly reduced as compared with the case where no overcoat layer is provided. .
- the glass material constituting the overcoat layer has a thermal conductivity 10 times higher than that of the silicone die bond material, the formation of the overcoat layer has little influence on reducing heat dissipation.
- a light-emitting element mounting substrate with low heat resistance and high heat dissipation is obtained. Further, by using this light emitting element mounting substrate, a light emitting device having excellent light extraction efficiency and high emission luminance can be obtained.
- the thickness of the overcoat layer is less than 3 times the surface roughness Ra of the mounting surface of the substrate body, it is difficult to sufficiently obtain the effect of reducing the unevenness of the substrate body surface by forming the overcoat layer, It is difficult to make the surface roughness Ra of the overcoat layer 0.15 ⁇ m or less.
- the surface roughness Ra of the overcoat layer exceeds 0.15 ⁇ m, not only the contact area between the overcoat layer and the light emitting element is reduced, but also it is difficult to reduce the thickness of the silicone die bond material. Therefore, the effect of improving heat dissipation cannot be obtained sufficiently.
- the thickness of the overcoat layer exceeds 20 times the surface roughness Ra of the substrate body, the thickness of the glass layer (overcoat layer) inserted between the light emitting element to be mounted and the substrate body. As a result, the heat dissipation from the light emitting element to the substrate body may be hindered.
- FIG. 1 is a plan view of an embodiment of a light emitting element mounting substrate according to the present invention as viewed from the upper surface (mounting surface) side
- FIG. 2 is a plan view as viewed from the lower surface (non-mounting surface) side
- FIG. 3 is a cross-sectional view of the light emitting element mounting substrate of FIG. 1 cut along line X-X ′.
- the light-emitting element mounting substrate 1 has a substrate body 2 that has a square planar shape and a substantially flat plate shape.
- substantially flat form means flat form on a visual level.
- “substantially” indicates a visual level.
- the substrate body 2 is made of an inorganic insulating material, and a frame 3 is formed on the upper surface (mounting surface).
- the frame 3 forms a cavity having a circular planar shape, and the bottom surface of the cavity is a mounting surface on which the light emitting element is mounted.
- a circular area surrounded by the frame 3 that is a mounting surface of the light emitting element is referred to as an entire mounting area 21.
- Examples of the inorganic insulating material constituting the substrate body 2 include an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, and a glass ceramic composition containing glass powder and ceramic powder.
- a ligation (LTCC) etc. are mentioned.
- LTCC is preferable from the viewpoints of high reflectivity, ease of production, easy processability, economy, and the like.
- the shape of the substrate body 2 is a square shape and a substantially flat plate shape in order to mount eight 2-wire type light emitting elements in electrical parallel connection.
- the shape, thickness, size and the like of the substrate body 2 are not particularly limited and can be changed according to the design of the light emitting device, such as the number of light emitting elements to be mounted and the arrangement method.
- the raw material composition of the sintered body (LTCC) of the glass ceramic composition constituting the substrate body 2, the sintering conditions, and the like will be described in the method for manufacturing a light emitting element mounting substrate described later.
- the substrate body 2 preferably has a bending strength of, for example, 250 MPa or more from the viewpoint of suppressing damage or the like when the light emitting element is mounted or after use.
- a wiring conductor layer 4 that is electrically connected to the light emitting element is provided in the entire mounting area 21 of the substrate body 2.
- the wiring conductor layer 4 is disposed at one anode side or cathode side electrode (that is, the first electrode) 41 disposed in the center of the entire mounting area 21 and at the periphery of the entire mounting area 21.
- the second electrode 42 the same number of eight electrodes as the light emitting elements to be mounted are arranged on the circumference surrounding the first electrode 41 at substantially equal intervals.
- a region excluding the formation portion of the wiring conductor layer 4 (that is, the first electrode 41 and the second electrode 42) from the entire mounting region 21 of the substrate body 2 is a region where the light emitting element can be mounted. Become.
- the number of the second electrodes 42 in the wiring conductor layer 4 disposed in the entire mounting region 21 is eight, which is the same as the number of the light emitting elements to be mounted.
- the wiring conductor layer 4 can be formed as necessary if there are a limited number of electrodes and other necessary electrodes. That is, the planar shape and arrangement position of the first electrode 41 constituting the wiring conductor layer 4 and the planar shape and number of the second electrodes 42 are not limited to those illustrated.
- the constituent material of the wiring conductor layer 4 is not particularly limited as long as it is the same as the wiring conductor layer used for a normal light emitting element mounting substrate. Specifically, it will be described in the manufacturing method described later.
- the thickness of the wiring conductor layer 4 is preferably 5 to 15 ⁇ m.
- An overcoat layer 5 made of a glass material is formed in the mountable area of the substrate body 2.
- the overcoat layer 5 is provided so as to cover at least the mounting portion of the light emitting element.
- the conductive layer 4 is formed so as to cover almost the entire mountable region at a slight distance from the end of the conductive layer 4.
- the mounting part which is a part in which a light emitting element is actually mounted is shown with the code
- the eight mounting portions T on which the eight light emitting elements are mounted are respectively arranged at substantially equal intervals in an annular region between the first electrode 41 and the second electrode 42 group.
- the overcoat layer 5 has a thickness of 3 to 20 times the surface roughness Ra of the mountable region of the substrate body 2 which is the base to be formed. And the surface roughness Ra of the formed overcoat layer 5 is 0.15 ⁇ m or less.
- the glass material constituting such an overcoat layer 5 will be described below.
- the glass material constituting the overcoat layer 5 contains at least SiO 2 and B 2 O 3 and glass containing at least one selected from Na 2 O and K 2 O as a constituent component. .
- this glass material can contain ceramic powder in a proportion of 10% by mass or less.
- the content of the ceramic powder is preferably 3% by mass or more.
- the overcoat layer made of a material mainly composed of glass means a glass material that may contain 10% by mass or less of ceramic powder.
- the strength of the overcoat layer 5 can be increased, and the heat dissipation of the overcoat layer 5 can be increased.
- the glass material preferably contains silica powder or alumina powder as ceramic powder.
- the ceramic powder contained in the glass material is at least one selected from silica powder, alumina powder, zirconia powder, and titania powder, and has an average particle diameter D 50 (hereinafter sometimes simply referred to as D 50 ).
- D 50 is a value obtained by a particle size measuring apparatus using a laser diffraction / scattering method.
- the content of the ceramic powder in the glass material can be set in a predetermined range depending on the particle size.
- D 50 is 1 to 2.5 ⁇ m
- the content is preferably 3 to 10% by mass. 8 mass% or less is preferable and 5 mass% or less is more preferable.
- D 50 is less than 1 ⁇ m, the content is preferably 3 to 5% by mass.
- the ceramic powder is contained in excess of 10% by mass, the fluidity of the glass material is deteriorated, and not only the flatness of the overcoat layer 5 is deteriorated, but also insufficient sintering is likely to occur. Moreover, when content is less than 3 mass%, it becomes difficult to acquire the improvement effect of flatness.
- This glass is expressed in mol% on the basis of oxide, SiO 2 62-84%, B 2 O 3 10-25%, Al 2 O 3 0-5%, MgO 0-10%, Na 2
- the total content of at least one selected from O and K 2 O is 1 to 5%
- the total content of SiO 2 and Al 2 O 3 is 62 to 84%
- at least selected from CaO, SrO and BaO A borosilicate glass having a total content of 5% or less when it contains one kind is preferred.
- composition is simply expressed as% in terms of mol% based on the following oxide.
- SiO 2 is a glass network former, a component that increases chemical durability, particularly acid resistance, and is essential. If it is less than 62%, the acid resistance may be insufficient. If it exceeds 84%, the glass melting temperature tends to be high, or the glass transition point (Tg) tends to be too high.
- B 2 O 3 is a glass network former and is essential. If it is less than 10%, the glass melting temperature tends to be high, and the glass may become unstable. Preferably it is 12% or more. If it exceeds 25%, not only is it difficult to obtain stable glass, but chemical durability may be reduced.
- Al 2 O 3 is not essential, but may be contained in a range of 5% or less in order to enhance the stability or chemical durability of the glass. If it exceeds 5%, the transparency of the glass may decrease.
- the total content of SiO 2 and Al 2 O 3 is 62 to 84%. If it is less than 62%, chemical durability may be insufficient. If it exceeds 84%, the glass melting temperature becomes high, or Tg becomes too high.
- Na 2 O and K 2 O are components that lower Tg, and at least one of them is essential. It can contain up to 5% in total. If it exceeds 5%, chemical durability, particularly acid resistance, may deteriorate. Moreover, there exists a possibility that the electrical insulation of a sintered compact may fall. Na 2 O, and containing any one or more of K 2 O, Na 2 O, it is preferable that the total content of K 2 O is not less than 1%.
- MgO is not essential, but may be contained up to 10% in order to lower Tg or stabilize the glass. Preferably it is 8% or less.
- CaO, SrO, and BaO are not essential, but may be contained up to 5% in total in order to lower the melting temperature of the glass or stabilize the glass. If it exceeds 5%, the acid resistance may decrease.
- the glass for the overcoat layer of the present invention consists essentially of the above components, but may contain other components within a range not to impair the purpose of the present invention. When such components are contained, the total content of these components is preferably 10% or less. However, lead oxide is not contained.
- the overcoat layer of the present invention is preferably formed by applying and baking a composition obtained by mixing such a borosilicate glass powder composed of each component and, if necessary, the ceramic powder.
- a composition obtained by mixing such a borosilicate glass powder composed of each component and, if necessary, the ceramic powder is formed into a paste, screen-printed, and fired.
- the method for forming the overcoat layer is not particularly limited as long as the method can flatly form a layer having a thickness 3 to 20 times the surface roughness Ra of the mountable region of the substrate body 2.
- the other surface of the substrate body 2 is a non-mounting surface 22 on which no light emitting element is mounted, and a pair (the anode side and the cathode side) of external electrode terminals 6 are provided on the non-mounting surface 22.
- These external electrode terminals 6 are electrically connected to the first electrode 41 and the second electrode 42 provided on the mounting surface of the substrate body 2 through connection vias 7 formed inside the substrate body 2 and the like. It is connected to the.
- the shape and constituent materials of the external electrode terminal 6 and the connection via 7 can be used without particular limitation as long as they are the same as those used for a substrate for mounting a light emitting element. Further, regarding the arrangement of the external electrode terminals 6 and the connection vias 7, the eight light emitting elements to be mounted are electrically connected via these and the wiring conductor layer 4 (that is, the first electrode 41 and the second electrode 42). It is only necessary to be arranged so as to be connected in parallel. This will be specifically described in the section of the substrate manufacturing method described later.
- the thermal via 8 and the heat dissipation layer 9 are embedded in the substrate body 2.
- the thermal via 8 has a columnar shape smaller than the mounting portion T of the light emitting element, for example, and is preferably arranged from the non-mounting surface 22 to the heat radiation layer 9 embedded inside. With such an arrangement, the flatness of the entire mounting area 21, particularly the mounting portion T, can be improved, the thermal resistance can be reduced, and the inclination when the light emitting element is mounted can be suppressed.
- the shape and arrangement of the thermal via 8 and the heat dissipation layer 9 will be specifically described in the section of the substrate manufacturing method described later.
- the embodiment of the light emitting element mounting substrate 1 of the present invention has been described above by way of an example, but the light emitting element mounting substrate of the present invention is not limited to this. As long as it does not contradict the spirit of the present invention, the configuration can be changed as necessary.
- the light emitting element mounting substrate 1 of the present invention configured as described above, materials and manufacturing methods generally used for the light emitting element mounting LTCC substrate can be applied. Moreover, the light emitting device of the present invention described later can also be manufactured by a normal method using a normal member except that the light emitting element mounting substrate 1 of the present invention is used.
- the light emitting element mounting substrate 1 shown in FIGS. 1 to 3 can be manufactured by a manufacturing method including the following steps (A) to (E).
- steps (A) to (E) members, forming material layers, and the like used in the manufacture will be described with the same reference numerals as those of the finished product.
- the overcoat layer and the overcoat glass paste layer are denoted by a symbol of 5, and the others are the same.
- a green sheet manufacturing process for main body A green sheet (green sheet for main body) and a frame for forming a substrate main body of a light emitting element mounting substrate using a glass ceramic composition including glass powder and ceramic powder.
- a green sheet for a frame is prepared for formation.
- the main body green sheet includes an upper layer green sheet for forming an upper layer, an inner layer green sheet for forming an inner layer, and a lower layer green sheet for forming a lower layer.
- (B) Conductive paste layer forming step By forming a conductive paste layer at a predetermined position on each main body green sheet, an unfired wiring conductor layer, an unfired external electrode terminal, an unfired connection via, an unfired thermal via, A fired heat dissipation layer or the like is formed.
- (D) Lamination process A plurality of unfired main body members (hereinafter referred to as green sheets with a conductive paste layer) obtained by forming a conductive paste layer (in addition, an overcoat glass paste layer in the upper green sheet) on the green sheet for the main body. , And a green sheet with an overcoat glass paste layer) and the like are overlapped and integrated by thermocompression bonding to obtain a green substrate.
- green sheets with a conductive paste layer obtained by forming a conductive paste layer (in addition, an overcoat glass paste layer in the upper green sheet) on the green sheet for the main body.
- a green sheet with an overcoat glass paste layer and the like are overlapped and integrated by thermocompression bonding to obtain a green substrate.
- a green sheet for main body is prepared by adding a binder, and if necessary, a plasticizer, a dispersant, a solvent, etc. to a glass ceramic composition containing glass powder and ceramic powder. Then, it can be produced by forming it into a sheet by the doctor blade method and drying it. Moreover, the green sheet for a frame is obtained by processing the green sheet thus produced into a predetermined shape.
- the glass powder for main body for producing the green sheet for main body preferably has a glass transition point (Tg) of 550 ° C. or higher and 700 ° C. or lower.
- Tg glass transition point
- degreasing may be difficult
- 700 ° C. the shrinkage start temperature becomes high and the dimensional accuracy may be lowered.
- the glass powder is one in which crystals are precipitated when fired at 800 ° C. or higher and 930 ° C. or lower. In the case where crystals do not precipitate, there is a possibility that sufficient mechanical strength cannot be obtained. Furthermore, the thing whose crystallization peak temperature (Tc) measured by DTA (differential thermal analysis) is 880 degrees C or less is preferable. When Tc exceeds 880 ° C., the dimensional accuracy may be reduced.
- SiO 2 is 57 to 65%
- B 2 O 3 is 13 to 18%
- CaO is 9 to 23%
- Al 2 O 3 is expressed in mol% on the basis of the following oxides. It preferably contains 3 to 8% and at least one selected from K 2 O and Na 2 O in a total amount of 0.5 to 6%.
- SiO 2 serves as a glass network former.
- the content of SiO 2 is preferably 58% or more, more preferably 59% or more, and particularly preferably 60% or more. Further, the content of SiO 2 is preferably 64% or less, more preferably 63% or less.
- B 2 O 3 is a glass network former. If the content of B 2 O 3 is less than 13%, there is a possibility that the glass melting temperature or Tg may be too high. On the other hand, when the content of B 2 O 3 exceeds 18%, it is difficult to obtain a stable glass, and the chemical durability may be lowered.
- the content of B 2 O 3 is preferably 14% or more, more preferably 15% or more. Further, the content of B 2 O 3 is preferably 17% or less, more preferably 16% or less.
- Al 2 O 3 is added to increase the stability, chemical durability, and strength of the glass. If the content of Al 2 O 3 is less than 3%, the glass may become unstable. On the other hand, when the content of Al 2 O 3 exceeds 8%, the glass melting temperature and Tg may be excessively high.
- the content of Al 2 O 3 is preferably 4% or more, more preferably 5% or more. Further, the content of Al 2 O 3 is preferably 7% or less, more preferably 6% or less.
- CaO is added to increase glass stability and crystal precipitation, and to lower the glass melting temperature and Tg.
- the content of CaO is less than 9%, the glass melting temperature may be excessively high.
- the content of CaO exceeds 23%, the glass may become unstable.
- the content of CaO is preferably 12% or more, more preferably 13% or more, and particularly preferably 14% or more. Further, the content of CaO is preferably 22% or less, more preferably 21% or less, and particularly preferably 20% or less.
- K 2 O and Na 2 O are added to lower Tg.
- the glass melting temperature and Tg may be excessively high.
- the total content of K 2 O and Na 2 O exceeds 6%, chemical durability, particularly acid resistance may be lowered, and electrical insulation may be lowered.
- the total content of K 2 O and Na 2 O is preferably 0.8% or more and 5% or less.
- the glass powder for main bodies is not necessarily limited to what consists only of the said component, Other components can be contained in the range with which various characteristics, such as Tg, are satisfy
- the glass powder for main body is obtained by manufacturing glass having the above composition by a melting method and pulverizing it by a dry pulverization method or a wet pulverization method.
- a wet pulverization method it is preferable to use water or ethyl alcohol as a solvent.
- the pulverizer include a roll mill, a ball mill, and a jet mill.
- the 50% particle size (D 50 ) of the glass powder for main body is preferably 0.5 ⁇ m or more and 2 ⁇ m or less. If D 50 of the glass powder is less than 0.5 [mu] m, it glass powder is likely to agglomerate, handle not only difficult, uniform dispersion becomes difficult. On the other hand, if the D 50 of the glass powder exceeds 2 ⁇ m, there is a possibility that increase and insufficient sintering of the glass softening temperature is generated.
- the particle diameter may be adjusted by classification as necessary after pulverization, for example.
- the ceramic powder those conventionally used for the production of LTCC substrates can be used.
- alumina powder, zirconia powder, or a mixture of alumina powder and zirconia powder can be suitably used.
- a ceramic powder hereinafter referred to as a high refractive index ceramic powder
- a high refractive index ceramic powder having a higher refractive index than alumina together with the alumina powder.
- the high refractive index ceramic powder is a component for improving the reflectivity of the base body obtained by sintering by the firing process described below.
- titania powder, zirconia powder, stabilized zirconia powder, zinc oxide powder, titanium examples thereof include barium acid powder and lead titanate powder.
- the refractive index of alumina is about 1.8
- the refractive index of titania is about 2.7
- the refractive index of zirconia is about 2.2, which is higher than that of alumina.
- D 50 of these ceramic powders is preferably 0.5 ⁇ m or more and 4 ⁇ m or less.
- the glass ceramic composition is mixed. Things are obtained.
- a desired slurry can be obtained by adding a binder and, if necessary, a plasticizer, a dispersant, a solvent, and the like to the glass ceramic composition.
- binder for example, polyvinyl butyral, acrylic resin or the like can be suitably used.
- plasticizer for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate and the like can be used.
- solvent organic solvents such as toluene, xylene, 2-propanol and 2-butanol can be preferably used.
- the slurry thus obtained is formed into a sheet by a doctor blade method or the like and dried to produce three green sheets for the main body (upper layer green sheet, lower layer green sheet and inner layer green sheet). .
- a green sheet for a frame is manufactured by processing the green sheet manufactured in the same manner into a predetermined shape.
- Conductive paste layer forming step A conductive paste layer for forming a wiring conductive layer, external electrode terminals, connection vias, thermal vias, heat dissipation layers, etc. on the surface and inside of the green sheet for main body produced in the above step. Form. That is, as shown in FIG. 4, a circular first electrode conductor paste layer 41 is formed in the center of the entire mounting area 21 corresponding to the element mounting surface in the upper layer green sheet 23.
- a ring-shaped connecting conductor paste layer 43 is formed so as to surround the first electrode conductor paste layer 41, and the eight second electrode conductor paste layers 42 are connected to the connecting conductor paste layer 43. It is formed at substantially equal intervals so as to extend inward from the inside. Further, the connection via conductor paste layer 7 is formed through the upper layer green sheet 23 at a predetermined position of the central portion of the first electrode conductor paste layer 41 and the connecting conductor paste layer 43.
- a heat dissipating layer conductor paste layer 9 is formed on the upper surface thereof, and a plurality of connection via conductor paste layers 7 are formed so as to penetrate the green sheet.
- a plurality of conductor paste layers 8 for thermal vias are formed.
- connection via conductor paste layers 7 and a plurality of thermal via conductor paste layers 8 are formed so as to penetrate the lower layer green sheet 25, and A conductor paste layer 6 for external electrode terminals is formed on the lower surface.
- Each green sheet is formed with a large number of regions corresponding to a large number of light emitting devices, and these are divided after the final baking step, but in FIGS. 4 to 6, they correspond to a single light emitting device. An area for forming one light emitting element mounting substrate is shown.
- Examples of the method for forming the conductive paste layer 6 include a method of applying and filling the conductive paste by screen printing. The thickness of these formed conductive paste layers is such that the first and second electrodes, connection wirings, connection vias, heat dissipation layers, thermal vias, and external electrode terminals finally obtained have a predetermined thickness. It is adjusted to become.
- a paste obtained by adding a vehicle such as ethyl cellulose to a metal powder mainly composed of copper, silver, gold or the like, and a solvent or the like as required can be used.
- a metal powder silver powder, metal powder composed of silver and platinum, or metal powder composed of silver and palladium are preferably used.
- Overcoat glass paste layer forming step In the upper layer green sheet, overcoat is applied by screen printing so as to cover almost the entire mountable region except for the vicinity of the wiring conductor paste layer 4 formed in the step (B). A glass paste layer 5 is formed.
- the overcoat glass paste is a paste prepared by adding a vehicle such as ethyl cellulose to a composition obtained by mixing the glass powder for the overcoat layer and the ceramic powder as necessary, and a solvent as necessary. What was made into a shape can be used.
- the thickness of the overcoat glass paste layer 5 to be formed is such that the thickness of the finally obtained overcoat layer 5 is 3 to 20 times the surface roughness Ra of the mountable area of the substrate body 2. In addition, the surface roughness Ra of the overcoat layer 5 is adjusted to be 0.15 ⁇ m or less.
- the surface roughness Ra of the overcoat layer 5 can be adjusted not only by the thickness of the overcoat layer 5, but also by the particle size and composition of the glass powder for the overcoat layer, the paste kneading method and the kneading time. . That is, as the glass powder for the overcoat layer, a glass powder having a composition and particle size excellent in fluidity that sufficiently melts during firing is used, and the composition of the mixture with the ceramic powder is excellent in fluidity during firing. By optimizing the kneading method and time, the surface roughness Ra of the overcoat layer 5 can be reduced. For example, when the surface roughness Ra of the mountable region of the substrate body 2 is 0.30 to 0.35 ⁇ m, the thickness of the overcoat layer 5 after firing is set to 0.9 to 7.0 ⁇ m.
- step (D) Lamination process Green sheet with conductor paste layer (unfired main body member) obtained in step (B) and green sheet with overcoat glass paste layer obtained in step (C) in a predetermined order
- the green sheet for frame is further stacked on the upper layer green sheet 23, and then integrated by thermocompression bonding. Thus, an unfired substrate is obtained.
- the above-described degreasing is performed, for example, under the condition of holding at a temperature of 500 ° C. to 600 ° C. for 1 hour to 10 hours.
- the degreasing temperature is less than 500 ° C. or the degreasing time is less than 1 hour, the binder or the like may not be sufficiently removed.
- the degreasing temperature is about 600 ° C. and the degreasing time is about 10 hours, the binder and the like can be sufficiently removed, and if it exceeds this, productivity and the like may be lowered.
- the firing can be appropriately adjusted in a temperature range of 800 ° C. to 930 ° C. in consideration of obtaining a dense structure of the base body 2 and productivity. Specifically, it is preferable to hold at a temperature of 850 ° C. or more and 900 ° C. or less for 20 minutes or more and 60 minutes or less, and a temperature of 860 ° C. or more and 880 ° C. or less is particularly preferable. If the firing temperature is less than 800 ° C., the base body 2 may not be obtained as a dense structure. On the other hand, if the firing temperature exceeds 930 ° C., the productivity may be lowered due to deformation of the base body 2.
- the light-emitting element mounting substrate 1 is obtained. After firing, the surface of the wiring conductor layer 4 (first and second electrodes 41, 42) exposed on the mounting surface is coated as necessary. It is also possible to dispose a conductive protective film used for protecting the conductor in the light emitting element mounting substrate 1 such as Ni / gold plating two-layer plating.
- the frame green sheet need not be a single green sheet, and may be a laminate of a plurality of green sheets. Further, the number of main body green sheets excluding the frame green sheet is not necessarily three, and may be two or four or more. Further, the order of forming each part can be appropriately changed as long as the light emitting element mounting substrate 1 can be manufactured.
- FIG. 7 is a plan view of an embodiment of the light emitting device of the present invention as viewed from the upper surface side
- FIG. 8 is a cross-sectional view of the light emitting device of FIG. 7 cut along the line Y-Y ′.
- FIG. 7 shows a state where the resin sealing layer is removed.
- the light-emitting device 10 of the present invention is mounted on the above-described light-emitting element mounting substrate 1 of the present invention and the mounting portion of the light-emitting element mounting substrate 1, and a pair of electrodes each have a predetermined wiring conductor layer 4 (first 8 light-emitting elements (for example, LED elements) 11 of a two-wire type, which are wire-bonded to one electrode 41 and second electrode 42) and connected in parallel.
- first 8 light-emitting elements for example, LED elements
- all the eight light emitting elements 11 are rectangular parallelepiped light emitting elements whose bottom surfaces are squares of the same size, and are arranged on the eight mounting portions T of the light emitting element mounting substrate 1, respectively. Then, it is fixed to the mounting portion using a silicone die bond material (not shown) that is an adhesive.
- each light emitting element 11 is connected to the second electrode 42 located at the center of the entire mounting region 21 of the light emitting element mounting substrate 1 by the bonding wire 12, and the other Are connected by the bonding wire 12 to the closest electrode in the group of eight second electrodes 42.
- the 16 bonding wires 12 connecting the 8 to 16 electrodes of the 8 light emitting elements 11 are arranged so as not to cross each other. Further, a sealing layer 13 made of mold resin is provided so as to cover these light emitting elements 11 and bonding wires 12.
- the arrangement of the light emitting element 11 in the light emitting device 10 of the present invention is such that at least the electrode of the light emitting element 11 and the wiring conductor layer 4 (first electrode 41 and second electrode 42) of the light emitting element mounting substrate 1 are connected. As long as the bonding wires 12 do not cross each other, the arrangement is not limited to the arrangement shown in FIG.
- the overcoat layer 5 having a thickness 3 to 20 times the surface roughness Ra of the mounting surface is formed on the mounting surface of the substrate body 2. Since the light emitting element mounting substrate 1 having a thickness Ra of 0.15 ⁇ m or less is used, the heat dissipation from the light emitting element 11 to the substrate body 2 is excellent, and the light extraction efficiency is excellent. Luminous light emission is possible.
- a light emitting device 10 can be suitably used, for example, as a backlight for a mobile phone, a large-sized liquid crystal display, etc., illumination for automobiles or decoration, and other light sources.
- Examples 1 to 3 Comparative Examples 1 and 2
- the light emitting element mounting substrate as shown in FIGS. 1 to 6 and the light emitting device shown in FIGS. 7 and 8 were manufactured by the following method.
- main body green sheets (upper layer green sheet, lower layer green sheet, and inner layer green sheet) for manufacturing the substrate body 2 of the light emitting element mounting substrate 1 were manufactured.
- the green sheet for the main body in terms of mol% based on oxide, SiO 2 is 60.4%, B 2 O 3 is 15.6%, Al 2 O 3 is 6%, CaO is 15%, K
- the raw materials were blended and mixed so that 2 O was 1% and Na 2 O was 2%.
- the raw material mixture was put in a platinum crucible and melted at 1600 ° C. for 60 minutes, and then the molten glass was poured out and cooled. did.
- This glass was pulverized with an alumina ball mill for 40 hours to produce a glass powder for a main body.
- ethyl alcohol was used as a solvent for pulverization.
- the glass powder was 38% by mass
- the alumina filler manufactured by Showa Denko KK, trade name: AL-45H
- the zirconia filler manufactured by Daiichi Rare Element Chemical Industries, trade name: HSY-3F-J.
- this glass ceramic composition 15 g of an organic solvent (mixed with toluene, xylene, 2-propanol, 2-butanol in a mass ratio of 4: 2: 2: 1), a plasticizer (di-2-ethylhexyl phthalate) 2.5 g of polyvinyl butyral (trade name: PVK # 3000K, manufactured by Denka Co., Ltd.) as a binder, 5 g, and 0.5 g of a dispersant (trade name: BYK180, manufactured by Big Chemie) were blended and mixed to prepare a slurry. .
- an organic solvent mixed with toluene, xylene, 2-propanol, 2-butanol in a mass ratio of 4: 2: 2: 1
- a plasticizer di-2-ethylhexyl phthalate
- polyvinyl butyral trade name: PVK # 3000K, manufactured by Denka Co., Ltd.
- a dispersant trade name
- This slurry was applied onto a PET film by a doctor blade method, and the dried green sheets were laminated so that the thickness after firing was 0.5 mm to produce a green sheet for a main body. Further, a green sheet for a frame was manufactured by processing a green sheet manufactured in the same manner as the green sheet for a main body into a predetermined shape.
- conductive metal powder (silver powder, manufactured by Daiken Chemical Industry Co., Ltd., trade name: S550) and ethyl cellulose as a vehicle are blended at a mass ratio of 85:15, and the solvent is set so that the solid content is 85 mass%.
- the mixture After being dispersed in ⁇ -terpineol, the mixture was kneaded in a porcelain mortar for 1 hour, and further dispersed three times with a three roll to produce a metal paste (conductor paste).
- the conductor paste is screen-printed with the pattern shown in FIG. 4 so that the first electrode, the second electrode, and the connection are used. And forming a through hole having a diameter of 0.15 mm using a hole puncher in a portion corresponding to the connection via, and filling the conductor paste by a screen printing method, A connection via conductor paste layer 7 was formed.
- the conductor paste layer 9 for the heat radiation layer is formed on the upper surface of the green sheet 24 for the inner layer by screen printing with the pattern shown in FIG. 5, and the portions corresponding to the thermal vias and connection vias are perforated. Through holes having a diameter of 0.2 mm and a diameter of 0.15 mm were formed using a machine, and a conductor paste was filled by a screen printing method to form a thermal via conductor paste layer 8 and a connection via conductor paste layer 7.
- the conductor paste layer 6 for external electrode terminals is formed on the lower surface of the lower layer green sheet 25 by screen printing in the pattern shown in FIG. 6, and holes are formed in portions corresponding to the thermal vias and connection vias. Through holes having a diameter of 0.2 mm and a diameter of 0.15 mm were respectively formed using an emptying machine, and a conductive paste was filled by screen printing to form a thermal via conductor paste layer 8 and a connection via conductor paste layer 7. .
- the overcoat glass paste was screen-printed in the pattern shown in FIG. 4 on the mounting surface of the upper layer green sheet 23 on which the conductor paste layer was formed.
- a paste layer 5 was formed.
- Such overcoat glass paste layer 5 was not formed.
- the thickness of the overcoat glass paste layer 5 in Examples 1 to 3 is such that the thickness of the overcoat layer after firing is in the range of 3 to 20 times the surface roughness Ra of the mountable region of the substrate body 2. The thickness was adjusted to be as shown in Table 1.
- the thickness of the overcoat glass paste layer 5 in Comparative Example 2 is such that the thickness of the overcoat layer after baking exceeds 20 times the surface roughness Ra of the mountable region of the substrate body 2. It was adjusted.
- the surface roughness Ra of the mountable area of the substrate body 2 corresponds to the surface roughness Ra of the mounting surface of the light emitting element mounting substrate 1 obtained in Comparative Example 1, and the value is 0.31 ⁇ m as will be described later. Met.
- the overcoat glass paste was prepared as shown below. First, raw materials are blended and mixed so that SiO 2 is 81.6%, B 2 O 3 is 16.6%, and K 2 O is 1.8% in terms of mol% based on oxide. The mixture was put in a platinum crucible and melted at 1600 ° C. for 60 minutes, and then the molten glass was poured out and cooled. This glass was pulverized with an alumina ball mill for 8 to 60 hours to produce an overcoat glass powder. In addition, ethyl alcohol was used as a solvent for pulverization.
- the glass powder was mixed and mixed so that the glass powder was 95% by mass and the silica fine powder (manufactured by Nippon Aerosil Co., Ltd., trade name: AEROSIL 380, average particle size 7 nm) was 5% by mass. Subsequently, it mix
- AEROSIL 380 average particle size 7 nm
- the green sheet for the upper layer with the overcoat glass paste layer thus prepared, the green sheet for the inner layer with the conductive paste layer, and the green sheet for the lower layer (unfired main body member) are superposed in a predetermined order, and the upper layer
- the green sheet for the frame body was overlaid on the green sheet for use, and then integrated by thermocompression bonding. Thus, an unfired substrate was obtained.
- the obtained unfired substrate was degreased by holding at 550 ° C. for 5 hours, and further held and fired at 870 ° C. for 30 minutes to produce a light emitting element mounting substrate 1.
- the thickness of the overcoat layer 5 after firing was measured by cross-sectional observation.
- the cross-section including the overcoat layer 5 was mirror-polished and measured with an electron microscope (Hitachi High-Technologies S3000) at a magnification of 1500 times.
- the surface roughness Ra of the overcoat layer 5 was measured with Surfcom 1400D (manufactured by Tokyo Seimitsu Co., Ltd.). The measurement results are shown in Table 1.
- Comparative Example 1 in which the overcoat layer 5 was not provided the surface roughness Ra of the mounting surface of the substrate body 2 was measured in the same manner. The measurement results are shown in the column of the surface roughness Ra of the overcoat layer 5 and the like.
- the LED elements (trade name: ES-CEBLV24, manufactured by Epistar Co., Ltd.) are respectively fixed to the eight mounting portions 5 with a die bond material (trade name: KER-3000-M2 manufactured by Shin-Etsu Chemical Co., Ltd.).
- a pair of electrodes included in each LED element was electrically connected to the first electrode 41 and the second electrode 42 by the bonding wire 12, respectively. In this way, eight LED elements were electrically connected in parallel.
- a sealing layer 13 was formed using a sealing agent (trade name: SCR-1016A, manufactured by Shin-Etsu Chemical Co., Ltd.).
- the thermal resistance of the light emitting device 10 thus obtained was measured by the following method. That is, the thermal resistance of the light-emitting element mounting substrate 1 in the light-emitting devices 10 obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was measured using a thermal resistance measuring instrument (trade name: TH-2167, manufactured by Gwangon Electric Co., Ltd.). ). The applied current was set to 960 mA, current was applied until the voltage drop was saturated, the saturation temperature was calculated from the dropped voltage and the temperature coefficient derived from the temperature-voltage drop characteristics of the light emitting element, and the thermal resistance was obtained.
- a thermal resistance measuring instrument (trade name: TH-2167, manufactured by Gwangon Electric Co., Ltd.).
- Table 1 shows the measurement results of thermal resistance.
- the thermal resistance is shown as a relative value when the thermal resistance in the light emitting device 10 of Comparative Example 1 in which the overcoat layer 5 is not formed on the mounting surface of the substrate body is 100. It means that heat dissipation is so favorable that a numerical value is small.
- the overcoat layer 5 has a thickness 3 to 20 times the surface roughness Ra of the mounting surface of the substrate body 2 (corresponding to the surface roughness Ra in Comparative Example 1) 0.31 ⁇ m, and In the light emitting devices 10 of Examples 1 to 3 in which the surface roughness Ra of the overcoat layer 5 itself is 0.15 ⁇ m or less, the thermal resistance is higher than that of the light emitting device 10 of Comparative Example 1 that does not have the overcoat layer 5. Is significantly reduced, and it can be seen that the heat dissipation is high.
- the surface roughness Ra of the overcoat layer 5 is extremely small. Although the smoothness and flatness of the surface of the layer 5 is good, a thick overcoat layer made of a glass material becomes an obstacle to heat conduction, so that the thermal resistance is high.
- the light-emitting element mounting substrate has high reflectivity and excellent heat dissipation. Therefore, when this substrate is used as a light-emitting device, the light extraction efficiency is good and the brightness is high. Can be obtained. And the light-emitting device of this invention using such a light emitting element mounting substrate can be used conveniently as backlights, such as a mobile telephone and a large sized liquid crystal display, the illumination for motor vehicles or decoration, and another light source, for example. It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application 2010-209663 filed on September 17, 2010 are incorporated herein as the disclosure of the present invention. .
- SYMBOLS 1 Light emitting element mounting substrate, 2 ... Substrate body, 3 ... Frame, 4 ... Wiring conductor layer (wiring conductor paste layer), 5 ... Overcoat layer (overcoat glass paste layer), 6 ... External electrode terminal (external) Conductor paste layer for electrode terminals), 7 ... Connection via (conductor paste layer for connection via), 8 ... thermal via (conductor paste layer for thermal via), 9 ... heat dissipation layer (conductor paste layer for heat dissipation layer), 10 ... light emission Device: 11 ... Light emitting element, 12 ... Bonding wire, 13 ... Sealing layer, 21 ... Whole mounting area, 41 ... First electrode (first electrode conductor paste layer), 42 ... Second electrode (second electrode) Electrode conductor paste layer), 43... Connecting conductor layer (connecting conductor electrode conductor paste layer).
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Abstract
Provided is a substrate for mounting a light-emitting element, wherein the reflectance of the substrate main body is high, and the performance of dissipating heat from the light-emitting element mounted on the substrate to the substrate is improved. Also provided is a light-emitting device exerting excellent light extraction efficiency, having a high emission luminance, and using such a substrate for mounting a light-emitting element. Specifically provided is a substrate for mounting a light-emitting element, the substrate being provided with: a substrate main body formed from an inorganic insulating material and having a mounting surface containing a mounting unit to which a light-emitting element is mounted; and an overcoat layer formed from a material mainly comprising glass and formed on the mounting surface of the substrate main body so as to at least cover the mounting unit. The overcoat layer has a thickness that is 3 to 20 times the surface roughness (Ra) of the mounting surface of the substrate main body, and the surface roughness (Ra) of the overcoat layer is 0.15 µm or less.
Description
本発明は、発光素子搭載用基板および発光装置に係り、特に、熱抵抗が低く放熱性が高い発光素子用基板と、これを用いた発光装置に関する。
The present invention relates to a light-emitting element mounting substrate and a light-emitting device, and more particularly, to a light-emitting element substrate having low thermal resistance and high heat dissipation, and a light-emitting device using the same.
近年、発光ダイオード（ＬＥＤ）素子の高輝度、白色化に伴い、携帯電話や大型液晶ＴＶのバックライト等としてＬＥＤ素子を用いた発光装置が使用されている。しかし、ＬＥＤ素子の高輝度化に伴って発熱量が増加しているため、ＬＥＤ素子等の発光素子を搭載するための基板として、樹脂基板に代わり、耐熱性が高くかつ発光素子から発生する熱を速やかに放散して、十分な発光輝度が得られるものが求められている。
In recent years, with the increase in brightness and whiteness of light emitting diode (LED) elements, light emitting devices using LED elements are used as backlights for mobile phones and large liquid crystal TVs. However, since the amount of heat generation increases as the brightness of the LED element increases, the substrate for mounting the light emitting element such as the LED element, instead of the resin substrate, has high heat resistance and heat generated from the light emitting element. There is a need for a material that can quickly dissipate the light and obtain sufficient light emission luminance.
従来から、発光素子搭載用基板として、例えばアルミナ基板が用いられているが、アルミナ基板は、光反射率が低く基板に入射した光が透過してしまうため、基板表面に銀反射膜が形成されている。しかし、この構造では、銀反射膜の酸化や硫化による反射率低下を防止するため、銀反射膜の表面にガラス等からなる保護層を設ける必要があり、光取り出し効率を十分に高くすることができなかった。すなわち、基板の上に銀反射膜を設ける場合、銀反射膜の面積はできるだけ大きい方が光取り出し効率が高くなるが、通常基板に搭載されるワイヤボンディングタイプの発光素子は、基板の搭載面上に配線導体層を必要とし、この配線導体層と銀反射膜との絶縁を確保するためのギャップを設ける必要がある。しかし、この絶縁のために形成されるギャップからは、基板内に光が入射し、入射した光のほとんどが基板内を拡散反射して再放射が困難となることから、ギャップの存在が基板の反射率の低下をまねくという問題があった。
Conventionally, for example, an alumina substrate is used as a substrate for mounting a light emitting element. However, an alumina substrate has a low light reflectivity and transmits light incident on the substrate, so that a silver reflection film is formed on the substrate surface. ing. However, in this structure, it is necessary to provide a protective layer made of glass or the like on the surface of the silver reflecting film in order to prevent the reflectance from being reduced due to oxidation or sulfuration of the silver reflecting film, and the light extraction efficiency can be sufficiently increased. could not. That is, when a silver reflective film is provided on a substrate, the light extraction efficiency is higher when the area of the silver reflective film is as large as possible. It is necessary to provide a wiring conductor layer and to provide a gap for ensuring insulation between the wiring conductor layer and the silver reflecting film. However, from the gap formed for this insulation, light enters the substrate, and most of the incident light is diffusely reflected inside the substrate, making it difficult to re-radiate. There was a problem in that the reflectance was lowered.
また、アルミナ基板のようなセラミックス基板に比べて反射率の高い発光素子搭載用基板として、低温同時焼成セラミックス基板（以下、ＬＴＣＣ基板という。）が使用されている。ＬＴＣＣ基板は、アルミナ粉末のようなセラミックス粉末とガラスとの焼結体からなり、ガラスとセラミックスとの屈折率差が大きく、光の入射方向に面する両者の界面の占める割合が多く、かつセラミックス粉末の粒径が使用波長より大きいことから、高い反射率が得られる。そのため、発光素子からの光を効率よく利用し、結果として発熱量を低減できる。また、光源による劣化の少ない無機酸化物からなるため、長期間に亘って色調が安定する。
Also, a low-temperature co-fired ceramic substrate (hereinafter referred to as an LTCC substrate) is used as a light-emitting element mounting substrate having a higher reflectance than a ceramic substrate such as an alumina substrate. The LTCC substrate is made of a sintered body of ceramic powder such as alumina powder and glass, and has a large refractive index difference between the glass and ceramic, and a large proportion of the interface between the two facing the light incident direction. Since the particle size of the powder is larger than the wavelength used, a high reflectance can be obtained. Therefore, the light from the light emitting element can be used efficiently, and as a result, the heat generation amount can be reduced. Moreover, since it consists of an inorganic oxide with little deterioration by a light source, a color tone is stabilized over a long period of time.
このようなＬＴＣＣ基板において、前記した銀反射膜のような反射膜を設けないで光取り出し効率を高めるために、アルミナよりも屈折率の高いセラミックスの粉末（例えばジルコニア粉末）をアルミナ粉末と併用するとともに、これらのセラミックス粉末の含有割合を通常のＬＴＣＣ基板に比べて高めることで、基板自体の反射率を向上させることが提案されている（例えば、特許文献１参照。）。
In such an LTCC substrate, ceramic powder (for example, zirconia powder) having a refractive index higher than that of alumina is used in combination with alumina powder in order to increase light extraction efficiency without providing a reflective film such as the above-described silver reflective film. At the same time, it has been proposed to improve the reflectance of the substrate itself by increasing the content ratio of these ceramic powders as compared to a normal LTCC substrate (see, for example, Patent Document 1).
しかし、このようなＬＴＣＣ基板では、通常のＬＴＣＣ基板に比べて表面粗さが大きいため、基板表面にＬＥＤ素子のような発光素子を搭載したとき、発光素子と基板との接触面積が小さくなり、発光素子から基板への放熱性が低くなるという問題があった。また、表面粗さが大きいＬＴＣＣ基板上に発光素子を搭載・実装する場合には、基板表面と発光素子との間の間隙に、熱伝導率の低いダイボンド材（シリコーンダイボンド材の熱伝導率は０．１Ｗ／ｍ・Ｋ）の厚い層が挟持されることになるため、発光素子から基板への熱の放散性がさらに低くなるという問題があった。
However, since the surface roughness of such an LTCC substrate is larger than that of a normal LTCC substrate, when a light emitting element such as an LED element is mounted on the substrate surface, the contact area between the light emitting element and the substrate is reduced. There has been a problem that heat dissipation from the light emitting element to the substrate is lowered. In addition, when mounting and mounting a light emitting element on an LTCC substrate having a large surface roughness, a die bond material having a low thermal conductivity (the thermal conductivity of the silicone die bond material is equal to the gap between the substrate surface and the light emitting element) Since a thick layer of 0.1 W / m · K) is sandwiched, there is a problem that heat dissipation from the light emitting element to the substrate is further reduced.
なお、セラミックス基板表面の平滑化に関しては、従来から、基板表面に非晶質のガラスを数十μｍの厚さに焼き付けるグレーズ処理が行われている。（例えば、特許文献２、特許文献３、特許文献４参照。）
Incidentally, with respect to the smoothing of the ceramic substrate surface, conventionally, a glazing process is performed in which amorphous glass is baked on the substrate surface to a thickness of several tens of μm. (For example, see Patent Document 2, Patent Document 3, and Patent Document 4.)
しかしながら、これらの特許文献に記載されているグレーズ処理は、ファクシミリのサーマルヘッドやプリンタヘッド用の基板製造において、微細な配線パターンを精度良く形成するために行なわれており、放熱性の向上を目的とするものではない。そして、これらの技術は、基板表面へのガラス層形成の目的が、放熱性の向上ではなく、微細配線パターンの形成精度の向上であるので、形成されるガラス層の厚さならびにガラス層に所望される表面粗さはその目的に沿ったものであり、放熱性の点で十分な効果を得ることができなかった。
However, the glaze process described in these patent documents is performed in order to accurately form a fine wiring pattern in the manufacture of a substrate for a thermal head of a facsimile or a printer head. It is not something to do. In these techniques, the purpose of forming the glass layer on the substrate surface is not to improve heat dissipation but to improve the formation accuracy of the fine wiring pattern. The surface roughness is in line with its purpose, and a sufficient effect cannot be obtained in terms of heat dissipation.
本発明は、上記問題を解決するためになされたものであって、反射膜を設けることなく基板本体の反射率の向上が図られており、かつ搭載される発光素子から基板への放熱性が向上された発光素子搭載用基板と、そのような発光素子搭載用基板を用いた光取り出し効率に優れ発光輝度の高い発光装置の提供を目的とする。
The present invention has been made in order to solve the above-described problem, and the reflectance of the substrate body is improved without providing a reflective film, and the heat dissipation from the mounted light emitting element to the substrate is achieved. It is an object of the present invention to provide an improved light emitting element mounting substrate and a light emitting device having high light emission luminance with excellent light extraction efficiency using such a light emitting element mounting substrate.
本発明の発光素子搭載用基板は、無機絶縁材料からなり、発光素子が搭載される搭載部を含む搭載面を有する基板本体と、前記基板本体の前記搭載面に少なくとも前記搭載部を覆うように形成された、ガラスを主体とする材料からなるオーバーコート層とを有し、前記オーバーコート層は、前記基板本体の前記搭載面の表面粗さＲａの３～２０倍の厚さを有し、かつ該オーバーコート層の表面粗さＲａは０．１５μｍ以下であることを特徴とする。
The light emitting element mounting substrate of the present invention is made of an inorganic insulating material and has a mounting surface including a mounting portion on which the light emitting element is mounted, and the mounting surface of the substrate main body covers at least the mounting portion. An overcoat layer made of a material mainly composed of glass, and the overcoat layer has a thickness of 3 to 20 times the surface roughness Ra of the mounting surface of the substrate body, The overcoat layer has a surface roughness Ra of 0.15 μm or less.
本発明の発光素子搭載用基板において、前記基板本体は、ガラス粉末とセラミックス粉末とを含むガラスセラミックス組成物の焼結体からなることが好ましい。そして、前記セラミックス粉末は、アルミナ粉末と、アルミナよりも高い屈折率を有するセラミックスの粉末を含むことが好ましい。また、前記セラミック粉末は、チタニア粉末、ジルコニア粉末、安定化ジルコニア粉末、酸化亜鉛粉末、チタン酸バリウム粉末、チタン酸鉛粉末からなる群から選ばれる少なくとも１種であることが好ましい。
In the light emitting element mounting substrate of the present invention, it is preferable that the substrate body is made of a sintered body of a glass ceramic composition containing glass powder and ceramic powder. The ceramic powder preferably includes an alumina powder and a ceramic powder having a higher refractive index than alumina. The ceramic powder is preferably at least one selected from the group consisting of titania powder, zirconia powder, stabilized zirconia powder, zinc oxide powder, barium titanate powder, and lead titanate powder.
また、本発明の発光素子搭載用基板において、前記オーバーコート層を構成する前記ガラスを主体とする材料は、８５０℃以下の軟化点を有することが好ましい。軟化点を８５０℃以下とすることにより、８６０℃以上８８０℃以下での焼成ができる。したがって、基板本体を焼成して得るときに、同時焼成でオーバーコート層の形成も可能となる。さらに、前記オーバーコート層を構成するガラスは、少なくとも、ＳｉＯ２およびＢ２Ｏ３を含有し、かつＮａ２ＯとＫ２Ｏから選ばれる少なくとも１種を含有することが好ましい。そして、前記ガラスは、酸化物基準のモル％表示で、ＳｉＯ２を６２～８４％、Ｂ２Ｏ３を１０～２５％、Ａｌ２Ｏ３を０～５％、ＭｇＯを０～１０％、Ｎａ２ＯおよびＫ２Ｏから選ばれる少なくとも１種を合計で１～５％含有し、ＳｉＯ２とＡｌ２Ｏ３の含有量の合計が６２～８４％であり、ＣａＯ、ＳｒＯおよびＢａＯから選ばれる少なくとも１種を含有する場合にその含有量の合計が５％以下であるホウケイ酸ガラス粉末が好ましい。
上記した数値範囲を示す「～」とは、特段の定めがない限り、その前後に記載された数値を下限値及び上限値として含む意味で使用され、以下本明細書において「～」は、同様の意味をもって使用される。 In the light emitting element mounting substrate of the present invention, it is preferable that the glass-based material constituting the overcoat layer has a softening point of 850 ° C. or lower. By setting the softening point to 850 ° C. or lower, firing at 860 ° C. or higher and 880 ° C. or lower can be performed. Therefore, when the substrate body is obtained by firing, an overcoat layer can be formed by simultaneous firing. Furthermore, the glass constituting the overcoat layer preferably contains at least SiO 2 and B 2 O 3 and at least one selected from Na 2 O and K 2 O. The glass is expressed in terms of mol% on the basis of oxide, SiO 2 62 to 84%, B 2 O 3 10 to 25%, Al 2 O 3 0 to 5%, MgO 0 to 10%, At least one selected from Na 2 O and K 2 O is contained in a total of 1 to 5%, the total content of SiO 2 and Al 2 O 3 is 62 to 84%, and selected from CaO, SrO and BaO A borosilicate glass powder having a total content of 5% or less is preferred when it contains at least one kind.
Unless otherwise specified, “to” indicating the numerical range described above is used to mean that the numerical values described before and after it are used as a lower limit value and an upper limit value, and hereinafter “to” Used with meaning.
上記した数値範囲を示す「～」とは、特段の定めがない限り、その前後に記載された数値を下限値及び上限値として含む意味で使用され、以下本明細書において「～」は、同様の意味をもって使用される。 In the light emitting element mounting substrate of the present invention, it is preferable that the glass-based material constituting the overcoat layer has a softening point of 850 ° C. or lower. By setting the softening point to 850 ° C. or lower, firing at 860 ° C. or higher and 880 ° C. or lower can be performed. Therefore, when the substrate body is obtained by firing, an overcoat layer can be formed by simultaneous firing. Furthermore, the glass constituting the overcoat layer preferably contains at least SiO 2 and B 2 O 3 and at least one selected from Na 2 O and K 2 O. The glass is expressed in terms of mol% on the basis of oxide, SiO 2 62 to 84%, B 2 O 3 10 to 25%, Al 2 O 3 0 to 5%, MgO 0 to 10%, At least one selected from Na 2 O and K 2 O is contained in a total of 1 to 5%, the total content of SiO 2 and Al 2 O 3 is 62 to 84%, and selected from CaO, SrO and BaO A borosilicate glass powder having a total content of 5% or less is preferred when it contains at least one kind.
Unless otherwise specified, “to” indicating the numerical range described above is used to mean that the numerical values described before and after it are used as a lower limit value and an upper limit value, and hereinafter “to” Used with meaning.
さらに本発明は、上記本発明の発光素子搭載用基板と、前記発光素子搭載用基板の前記搭載部に搭載された発光素子を備えたことを特徴とする発光装置を提供する。
Furthermore, the present invention provides a light emitting device comprising the light emitting element mounting substrate of the present invention and a light emitting element mounted on the mounting portion of the light emitting element mounting substrate.
本発明の発光素子搭載用基板においては、無機絶縁材料からなる基板本体の搭載面の少なくとも搭載部に、ガラスを主体とする材料からなり、搭載面の表面粗さＲａの３～２０倍の厚さを有するオーバーコート層が形成され、オーバーコート層の表面粗さＲａが０．１５μｍ以下と極めて表面平滑に構成されているので、このオーバーコート層と発光素子との接触面積を増大するとともに、これらの層間に介在される熱伝導率の低いダイボンド材の厚さを低減できる。したがって、発光素子から基板への熱抵抗が低減され、放熱性が向上した発光素子搭載用基板を提供できる。また、この発光素子搭載用基板を用いることで、光取り出し効率に優れ発光輝度の高い発光装置を提供できる。
In the light emitting element mounting substrate of the present invention, at least the mounting portion of the mounting surface of the substrate body made of an inorganic insulating material is made of a material mainly made of glass, and has a thickness 3 to 20 times the surface roughness Ra of the mounting surface. An overcoat layer having a thickness is formed, and the surface roughness Ra of the overcoat layer is 0.15 μm or less and is configured to be extremely smooth, so that the contact area between the overcoat layer and the light emitting element is increased, The thickness of the die bond material having low thermal conductivity interposed between these layers can be reduced. Therefore, the thermal resistance from the light emitting element to the substrate can be reduced, and a light emitting element mounting substrate with improved heat dissipation can be provided. Further, by using this light emitting element mounting substrate, a light emitting device having excellent light extraction efficiency and high light emission luminance can be provided.
以下、本発明の実施の形態について説明するが、本発明はこれに限定されるものではない。
Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.
本発明の発光素子搭載用基板は、無機絶縁材料からなり、部分的に発光素子が搭載される搭載部となる搭載面を有する基板本体と、この基板本体の搭載面に、少なくとも前記搭載部を覆うように形成されたガラスを主体とする材料（以下、ガラス材料ということもある。）からなるオーバーコート層を有する。そして、オーバーコート層は、基板本体の搭載面の表面粗さＲａの３～２０倍の厚さを有している。また、オーバーコート層の表面粗さＲａは０．１５μｍ以下となっている。ここで、表面粗さＲａは、ＪＩＳ：Ｂ０６０１（１９９４年）の３「定義された算術平均粗さの定義及び表示」によって表されるものであり、サーフコム１４００Ｄ（機種名、東京精密社製）により測定された値である。
The light emitting element mounting substrate of the present invention is made of an inorganic insulating material, and has a substrate body having a mounting surface as a mounting portion on which the light emitting element is partially mounted, and at least the mounting portion is mounted on the mounting surface of the substrate body. An overcoat layer made of a glass-based material (hereinafter sometimes referred to as a glass material) formed so as to cover is provided. The overcoat layer has a thickness 3 to 20 times the surface roughness Ra of the mounting surface of the substrate body. Further, the surface roughness Ra of the overcoat layer is 0.15 μm or less. Here, the surface roughness Ra is represented by 3 “Definition and display of defined arithmetic average roughness” of JIS: B0601 (1994). Surfcom 1400D (model name, manufactured by Tokyo Seimitsu Co., Ltd.) Is a value measured by
本発明の発光素子搭載用基板においては、基板本体の搭載面の少なくとも搭載部に、搭載面の表面粗さＲａの３～２０倍の厚さのガラス材料からなるオーバーコート層が形成されており、形成されたオーバーコート層の表面が、表面粗さＲａ０．１５μｍ以下と極めて平滑になっているので、このオーバーコート層の上にＬＥＤ素子のような発光素子を搭載・実装するとき、オーバーコート層と発光素子との接触面積が大きくなっているとともに、これらの層間に介在される発光素子を接合するためのシリコーンダイボンド材の厚さを、オーバーコート層がない場合に比べて大幅に低減できる。そして、オーバーコート層を構成するガラス材料は、シリコーンダイボンド材に比べて熱伝導率が１０倍も高いことから、オーバーコート層の形成が放熱性を低下させる影響は小さいので、発光素子から基板本体への熱抵抗が低く放熱性が高い発光素子搭載用基板が得られる。また、この発光素子搭載用基板を使用することで、光取り出し効率に優れ発光輝度の高い発光装置が得られる。
In the light emitting element mounting substrate of the present invention, an overcoat layer made of a glass material having a thickness 3 to 20 times the surface roughness Ra of the mounting surface is formed on at least the mounting portion of the mounting surface of the substrate body. Since the surface of the formed overcoat layer is extremely smooth with a surface roughness Ra of 0.15 μm or less, when mounting and mounting a light emitting device such as an LED device on this overcoat layer, the overcoat layer The contact area between the layer and the light-emitting element is increased, and the thickness of the silicone die bond material for joining the light-emitting element interposed between these layers can be greatly reduced as compared with the case where no overcoat layer is provided. . Since the glass material constituting the overcoat layer has a thermal conductivity 10 times higher than that of the silicone die bond material, the formation of the overcoat layer has little influence on reducing heat dissipation. Thus, a light-emitting element mounting substrate with low heat resistance and high heat dissipation is obtained. Further, by using this light emitting element mounting substrate, a light emitting device having excellent light extraction efficiency and high emission luminance can be obtained.
オーバーコート層の厚さが基板本体の搭載面の表面粗さＲａの３倍未満の場合には、オーバーコート層の形成により、基板本体表面の凹凸を低減する効果を十分に得ることが難しく、オーバーコート層の表面粗さＲａを０．１５μｍ以下にすることが困難である。そして、オーバーコート層の表面粗さＲａが０．１５μｍを超える場合には、このオーバーコート層と発光素子との接触面積が小さくなるばかりでなく、シリコーンダイボンド材の厚さを低減することが難しくなるので、放熱性の向上効果が十分に得られない。また、オーバーコート層の厚さが基板本体の表面粗さＲａの２０倍を超える場合には、搭載される発光素子と基板本体との間に挿入されるガラス層（オーバーコート層）の厚さが厚くなりすぎる結果、発光素子から基板本体への放熱を阻害するおそれがある。
When the thickness of the overcoat layer is less than 3 times the surface roughness Ra of the mounting surface of the substrate body, it is difficult to sufficiently obtain the effect of reducing the unevenness of the substrate body surface by forming the overcoat layer, It is difficult to make the surface roughness Ra of the overcoat layer 0.15 μm or less. When the surface roughness Ra of the overcoat layer exceeds 0.15 μm, not only the contact area between the overcoat layer and the light emitting element is reduced, but also it is difficult to reduce the thickness of the silicone die bond material. Therefore, the effect of improving heat dissipation cannot be obtained sufficiently. Further, when the thickness of the overcoat layer exceeds 20 times the surface roughness Ra of the substrate body, the thickness of the glass layer (overcoat layer) inserted between the light emitting element to be mounted and the substrate body. As a result, the heat dissipation from the light emitting element to the substrate body may be hindered.
以下、本発明の発光素子搭載用基板の一実施形態を図面に基づいて説明する。この実施形態は、２ワイヤタイプの発光素子８個を電気的に並列接続して搭載するために適用される発光素子搭載用基板の例を示すが、本発明はこれに限定されるものではない。
Hereinafter, an embodiment of a light emitting element mounting substrate of the present invention will be described with reference to the drawings. Although this embodiment shows an example of a light emitting element mounting substrate that is applied to mount eight 2-wire type light emitting elements in electrical parallel connection, the present invention is not limited to this. .
図１は、本発明の発光素子搭載用基板の一実施形態を上面（搭載面）側から見た平面図であり、図２は下面（非搭載面）側から見た平面図である。また、図３は、図１の発光素子搭載用基板をＸ－Ｘ’線で切断した断面図である。
FIG. 1 is a plan view of an embodiment of a light emitting element mounting substrate according to the present invention as viewed from the upper surface (mounting surface) side, and FIG. 2 is a plan view as viewed from the lower surface (non-mounting surface) side. FIG. 3 is a cross-sectional view of the light emitting element mounting substrate of FIG. 1 cut along line X-X ′.
この発光素子搭載用基板１は、平面形状が正方形で略平板状の基板本体２を有している。なお、本明細書において、略平板状とは、目視レベルで平板状との意味である。以下、「略」は目視レベルを示す。基板本体２は無機絶縁材料からなり、上面（搭載面）に枠体３が形成されている。そして、この枠体３により平面形状が円形のキャビティが形成されており、キャビティの底面は、発光素子の搭載される搭載面となっている。なお、発光素子の搭載面である、枠体３により囲まれた円形の領域を、搭載全体領域２１と示す。
The light-emitting element mounting substrate 1 has a substrate body 2 that has a square planar shape and a substantially flat plate shape. In addition, in this specification, substantially flat form means flat form on a visual level. Hereinafter, “substantially” indicates a visual level. The substrate body 2 is made of an inorganic insulating material, and a frame 3 is formed on the upper surface (mounting surface). The frame 3 forms a cavity having a circular planar shape, and the bottom surface of the cavity is a mounting surface on which the light emitting element is mounted. A circular area surrounded by the frame 3 that is a mounting surface of the light emitting element is referred to as an entire mounting area 21.
基板本体２を構成する無機絶縁材料としては、酸化アルミニウム質焼結体（アルミナセラミックス）、窒化アルミニウム質焼結体、ムライト質焼結体、ガラス粉末とセラミックス粉末とを含むガラスセラミックス組成物の焼結体（ＬＴＣＣ）等が挙げられる。本発明においては、高反射性、製造の容易性、易加工性、経済性等の観点から、ＬＴＣＣが好ましい。
Examples of the inorganic insulating material constituting the substrate body 2 include an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, and a glass ceramic composition containing glass powder and ceramic powder. A ligation (LTCC) etc. are mentioned. In the present invention, LTCC is preferable from the viewpoints of high reflectivity, ease of production, easy processability, economy, and the like.
本実施形態において、基板本体２の形状は、２ワイヤタイプの発光素子を８個、電気的に並列接続して搭載するために、平面形状が正方形で略平板状となっているが、本発明において、基板本体２の形状、厚さ、大きさ等は特に制限されず、搭載する発光素子の個数や配置の方法等、発光装置の設計に合わせて変更できる。また、基板本体２を構成するガラスセラミックス組成物の焼結体（ＬＴＣＣ）の原料組成、焼結条件等については、後述する発光素子搭載用基板の製造方法において説明する。基板本体２は、発光素子の搭載時やその後の使用時における損傷等を抑制する観点から、抗折強度が例えば２５０ＭＰａ以上であることが好ましい。
In the present embodiment, the shape of the substrate body 2 is a square shape and a substantially flat plate shape in order to mount eight 2-wire type light emitting elements in electrical parallel connection. However, the shape, thickness, size and the like of the substrate body 2 are not particularly limited and can be changed according to the design of the light emitting device, such as the number of light emitting elements to be mounted and the arrangement method. Moreover, the raw material composition of the sintered body (LTCC) of the glass ceramic composition constituting the substrate body 2, the sintering conditions, and the like will be described in the method for manufacturing a light emitting element mounting substrate described later. The substrate body 2 preferably has a bending strength of, for example, 250 MPa or more from the viewpoint of suppressing damage or the like when the light emitting element is mounted or after use.
基板本体２の搭載全体領域２１には、発光素子と電気的に接続される配線導体層４が設けられている。配線導体層４は、搭載全体領域２１の中央に配設された、１個のアノード側またはカソード側電極（すなわち、第１の電極）４１と、搭載全体領域２１の周辺部に配設された、第１の電極と反対極側の複数の電極（すなわち、第２の電極）４２を有する。第２の電極４２としては、搭載される発光素子と同数の８個の電極が、それぞれ第１の電極４１を囲む円周上に略等間隔で配設されている。なお、基板本体２の搭載全体領域２１から、このような配線導体層４（すなわち、第１の電極４１および第２の電極４２）の形成部を除いた領域が、発光素子の搭載可能領域となる。
In the entire mounting area 21 of the substrate body 2, a wiring conductor layer 4 that is electrically connected to the light emitting element is provided. The wiring conductor layer 4 is disposed at one anode side or cathode side electrode (that is, the first electrode) 41 disposed in the center of the entire mounting area 21 and at the periphery of the entire mounting area 21. And a plurality of electrodes (that is, second electrodes) 42 on the opposite side of the first electrode. As the second electrode 42, the same number of eight electrodes as the light emitting elements to be mounted are arranged on the circumference surrounding the first electrode 41 at substantially equal intervals. Note that a region excluding the formation portion of the wiring conductor layer 4 (that is, the first electrode 41 and the second electrode 42) from the entire mounting region 21 of the substrate body 2 is a region where the light emitting element can be mounted. Become.
本実施形態において、搭載全体領域２１に配設された配線導体層４のうちで第２の電極４２の個数は、搭載される発光素子の個数と同数の８個であるが、これは必要最小限の個数であり、それ以外に必要とする電極等があれば、必要に応じて配線導体層４を形成できる。すなわち、配線導体層４を構成する第１の電極４１の平面形状と配設位置、および第２の電極４２の平面形状、個数等は、図示のものに限定されない。また、配線導体層４の構成材料は、通常の発光素子搭載用基板に用いられる配線導体層と同様のものであれば特に制限されない。具体的には、後述する製造方法において説明する。配線導体層４の厚さは、５～１５μｍとすることが好ましい。
In the present embodiment, the number of the second electrodes 42 in the wiring conductor layer 4 disposed in the entire mounting region 21 is eight, which is the same as the number of the light emitting elements to be mounted. The wiring conductor layer 4 can be formed as necessary if there are a limited number of electrodes and other necessary electrodes. That is, the planar shape and arrangement position of the first electrode 41 constituting the wiring conductor layer 4 and the planar shape and number of the second electrodes 42 are not limited to those illustrated. In addition, the constituent material of the wiring conductor layer 4 is not particularly limited as long as it is the same as the wiring conductor layer used for a normal light emitting element mounting substrate. Specifically, it will be described in the manufacturing method described later. The thickness of the wiring conductor layer 4 is preferably 5 to 15 μm.
基板本体２の搭載可能領域には、ガラス材料からなるオーバーコート層５が形成されている。オーバーコート層５は、少なくとも発光素子の搭載部を覆うように設けられるが、層形成の容易性と、オーバーコート層５端部の盛り上がりが表面の平坦性に悪影響を与える点を考慮し、配線導体層４の端部から若干の距離をおいて、搭載可能領域のほぼ全域を覆うように形成するのが好ましい。なお、発光素子が実際に搭載される部分である搭載部を、図１に符号Ｔで示す。８個の発光素子が搭載される８個の搭載部Ｔは、第１の電極４１と第２の電極４２グループとの間の円環状の領域に、略等間隔でそれぞれ配設されている。
An overcoat layer 5 made of a glass material is formed in the mountable area of the substrate body 2. The overcoat layer 5 is provided so as to cover at least the mounting portion of the light emitting element. However, considering the ease of layer formation and the rise of the end portion of the overcoat layer 5 adversely affecting the flatness of the surface, Preferably, the conductive layer 4 is formed so as to cover almost the entire mountable region at a slight distance from the end of the conductive layer 4. In addition, the mounting part which is a part in which a light emitting element is actually mounted is shown with the code | symbol T in FIG. The eight mounting portions T on which the eight light emitting elements are mounted are respectively arranged at substantially equal intervals in an annular region between the first electrode 41 and the second electrode 42 group.
オーバーコート層５は、形成される下地である基板本体２の搭載可能領域の表面粗さＲａの３～２０倍の厚さを有している。そして、形成されたオーバーコート層５の表面粗さＲａは０．１５μｍ以下となっている。
The overcoat layer 5 has a thickness of 3 to 20 times the surface roughness Ra of the mountable region of the substrate body 2 which is the base to be formed. And the surface roughness Ra of the formed overcoat layer 5 is 0.15 μm or less.
このようなオーバーコート層５を構成するガラス材料について、以下に説明する。オーバーコート層５を構成するガラス材料は、少なくとも、ＳｉＯ２およびＢ２Ｏ３を含有し、かつＮａ２ＯとＫ２Ｏから選ばれる少なくとも１種を構成成分とするガラスを含有するものである。
The glass material constituting such an overcoat layer 5 will be described below. The glass material constituting the overcoat layer 5 contains at least SiO 2 and B 2 O 3 and glass containing at least one selected from Na 2 O and K 2 O as a constituent component. .
またこのガラス材料は、セラミックス粉末を１０質量％以下の割合で含有することができる。セラミックス粉末の含有量は好ましくは３質量％以上である。本発明において、ガラスを主体とする材料からなるオーバーコート層とは、セラミックス粉末を１０質量％以下含有してもよいガラス材料を意味する。セラミックス粉末を含有することにより、オーバーコート層５の強度を高くすることができ、また、オーバーコート層５の放熱性を高くできることができる。さらに、耐酸性のような耐薬品性の観点からは、前記ガラス材料はセラミックス粉末としてシリカ粉末またはアルミナ粉末を含有することが好ましい。
Further, this glass material can contain ceramic powder in a proportion of 10% by mass or less. The content of the ceramic powder is preferably 3% by mass or more. In the present invention, the overcoat layer made of a material mainly composed of glass means a glass material that may contain 10% by mass or less of ceramic powder. By containing ceramic powder, the strength of the overcoat layer 5 can be increased, and the heat dissipation of the overcoat layer 5 can be increased. Furthermore, from the viewpoint of chemical resistance such as acid resistance, the glass material preferably contains silica powder or alumina powder as ceramic powder.
さらに、前記ガラス材料に含有させるセラミック粉末として、シリカ粉末、アルミナ粉末、ジルコニア粉末、チタニア粉末から選ばれる少なくとも１種で、平均粒径Ｄ５０（以下、単にＤ５０と記載することもある。）が２．５μｍ以下、より好ましくは０．５μｍ以下の微粒子を用いることで、印刷性を高め、かつオーバーコート層５の端部を平坦化して、層表面のうねりを抑制できる。なお、Ｄ５０は、レーザ回折・散乱法による粒子径測定装置により得られる値をいう。
Further, the ceramic powder contained in the glass material is at least one selected from silica powder, alumina powder, zirconia powder, and titania powder, and has an average particle diameter D 50 (hereinafter sometimes simply referred to as D 50 ). By using fine particles having a thickness of 2.5 μm or less, more preferably 0.5 μm or less, the printability can be improved and the end of the overcoat layer 5 can be flattened to suppress waviness on the surface of the layer. Note that D 50 is a value obtained by a particle size measuring apparatus using a laser diffraction / scattering method.
ガラス材料中のセラミックス粉末の含有量は、粒径により所定の範囲に設定できる。Ｄ５０が１～２．５μｍのときには、含有量を３～１０質量％とするのが好ましい。８質量％以下が好ましく、５質量％以下がより好ましい。Ｄ５０が１μｍ未満のときには、その含有量は３～５質量％とすることが好ましい。
The content of the ceramic powder in the glass material can be set in a predetermined range depending on the particle size. When D 50 is 1 to 2.5 μm, the content is preferably 3 to 10% by mass. 8 mass% or less is preferable and 5 mass% or less is more preferable. When D 50 is less than 1 μm, the content is preferably 3 to 5% by mass.
１０質量％を超えてセラミックス粉末を含有させると、ガラス材料の流動性が悪化して、オーバーコート層５の平坦性が悪くなるばかりでなく、焼結不足が生じやすくなる。また、含有量が３質量％に満たない場合には、平坦性の向上効果が得られにくくなる。
If the ceramic powder is contained in excess of 10% by mass, the fluidity of the glass material is deteriorated, and not only the flatness of the overcoat layer 5 is deteriorated, but also insufficient sintering is likely to occur. Moreover, when content is less than 3 mass%, it becomes difficult to acquire the improvement effect of flatness.
次に、オーバーコート層５を構成するガラス材料の主成分であるガラスについて説明する。このガラスは、酸化物基準のモル％表示で、ＳｉＯ２を６２～８４％、Ｂ２Ｏ３を１０～２５％、Ａｌ２Ｏ３を０～５％、ＭｇＯを０～１０％、Ｎａ２ＯおよびＫ２Ｏから選ばれる少なくとも１種を合計で１～５％含有し、ＳｉＯ２とＡｌ２Ｏ３の含有量の合計が６２～８４％であり、ＣａＯ、ＳｒＯおよびＢａＯから選ばれる少なくとも１種を含有する場合にその含有量の合計が５％以下であるホウケイ酸ガラスが好ましい。
Next, the glass which is the main component of the glass material constituting the overcoat layer 5 will be described. This glass is expressed in mol% on the basis of oxide, SiO 2 62-84%, B 2 O 3 10-25%, Al 2 O 3 0-5%, MgO 0-10%, Na 2 The total content of at least one selected from O and K 2 O is 1 to 5%, the total content of SiO 2 and Al 2 O 3 is 62 to 84%, and at least selected from CaO, SrO and BaO A borosilicate glass having a total content of 5% or less when it contains one kind is preferred.
このようなガラスの各成分について説明する。なお、以下では特に断らない限り、組成は下記酸化物基準のモル％表示で単に％と表記する。
Each component of such glass will be described. Hereinafter, unless otherwise specified, the composition is simply expressed as% in terms of mol% based on the following oxide.
ＳｉＯ２はガラスのネットワークフォーマであり、化学的耐久性、とくに耐酸性を高くする成分であり必須である。６２％未満では耐酸性が不十分となるおそれがある。８４％超ではガラス溶融温度が高くなる、またはガラス転移点（Ｔｇ）が高くなりすぎるおそれがある。
SiO 2 is a glass network former, a component that increases chemical durability, particularly acid resistance, and is essential. If it is less than 62%, the acid resistance may be insufficient. If it exceeds 84%, the glass melting temperature tends to be high, or the glass transition point (Tg) tends to be too high.
Ｂ２Ｏ３はガラスのネットワークフォーマであり、必須である。１０％未満ではガラス溶融温度が高くなり、またガラスが不安定になるおそれがある。好ましくは１２％以上である。２５％超では、安定なガラスを得にくくなるばかりでなく、化学的耐久性が低下するおそれがある。
B 2 O 3 is a glass network former and is essential. If it is less than 10%, the glass melting temperature tends to be high, and the glass may become unstable. Preferably it is 12% or more. If it exceeds 25%, not only is it difficult to obtain stable glass, but chemical durability may be reduced.
Ａｌ２Ｏ３は必須ではないが、ガラスの安定性または化学的耐久性を高めるために５％以下の範囲で含有してもよい。５％超ではガラスの透明性が低下するおそれがある。
Al 2 O 3 is not essential, but may be contained in a range of 5% or less in order to enhance the stability or chemical durability of the glass. If it exceeds 5%, the transparency of the glass may decrease.
ＳｉＯ２とＡｌ２Ｏ３の含有量の合計は６２～８４％である。６２％未満であると化学的耐久性が不十分になるおそれがある。８４％超であるとガラス溶融温度が高くなる、またはＴｇが高くなりすぎる。
The total content of SiO 2 and Al 2 O 3 is 62 to 84%. If it is less than 62%, chemical durability may be insufficient. If it exceeds 84%, the glass melting temperature becomes high, or Tg becomes too high.
Ｎａ２ＯおよびＫ２ＯはＴｇを低下させる成分であり、少なくとも一方は必須である。合計で５％まで含有することができる。５％超では化学的耐久性、特に耐酸性が悪化するおそれがある。また、焼結体の電気絶縁性が低下するおそれがある。Ｎａ２Ｏ、Ｋ２Ｏのいずれか１以上を含有し、Ｎａ２Ｏ、Ｋ２Ｏの含有量の合計は１％以上であることが好ましい。
Na 2 O and K 2 O are components that lower Tg, and at least one of them is essential. It can contain up to 5% in total. If it exceeds 5%, chemical durability, particularly acid resistance, may deteriorate. Moreover, there exists a possibility that the electrical insulation of a sintered compact may fall. Na 2 O, and containing any one or more of K 2 O, Na 2 O, it is preferable that the total content of K 2 O is not less than 1%.
ＭｇＯは必須ではないが、Ｔｇを低下させる、またはガラスを安定化させるために、１０％まで含有してもよい。好ましくは８％以下である。
MgO is not essential, but may be contained up to 10% in order to lower Tg or stabilize the glass. Preferably it is 8% or less.
ＣａＯ、ＳｒＯ、ＢａＯはいずれも必須ではないが、ガラスの溶融温度を低下させる、またはガラスを安定化させるために、合計で５％まで含有してもよい。５％超であると耐酸性が低下するおそれがある。
CaO, SrO, and BaO are not essential, but may be contained up to 5% in total in order to lower the melting temperature of the glass or stabilize the glass. If it exceeds 5%, the acid resistance may decrease.
本発明のオーバーコート層用のガラスは本質的に上記成分からなるが、本発明の目的を損なわない範囲でその他の成分を含有してもよい。そのような成分を含有する場合、それら成分の含有量の合計は１０％以下が好ましい。ただし、鉛酸化物は含有しない。
The glass for the overcoat layer of the present invention consists essentially of the above components, but may contain other components within a range not to impair the purpose of the present invention. When such components are contained, the total content of these components is preferably 10% or less. However, lead oxide is not contained.
本発明のオーバーコート層は、このような各成分からなるホウケイ酸ガラス粉末と、必要に応じて前記セラミックス粉末とを混合してなる組成物を塗布し、焼成してなるものが好ましい。例えば、前記組成を有するホウケイ酸ガラス粉末と前記セラミックス粉末との混合粉末を、ペースト化してスクリーン印刷し、焼成して形成される。しかし、基板本体２の搭載可能領域の表面粗さＲａの３～２０倍の厚さの層を平坦に形成できる方法であれば、特にオーバーコート層の形成方法は限定されない。
The overcoat layer of the present invention is preferably formed by applying and baking a composition obtained by mixing such a borosilicate glass powder composed of each component and, if necessary, the ceramic powder. For example, the mixed powder of the borosilicate glass powder having the above composition and the ceramic powder is formed into a paste, screen-printed, and fired. However, the method for forming the overcoat layer is not particularly limited as long as the method can flatly form a layer having a thickness 3 to 20 times the surface roughness Ra of the mountable region of the substrate body 2.
基板本体２の他方の面は、発光素子の搭載されない非搭載面２２とされており、この非搭載面２２には、一対（アノード側およびカソード側）の外部電極端子６が設けられている。これらの外部電極端子６は、それぞれ基板本体２の内部等に形成された接続ビア７を介して、基板本体２の搭載面に設けられた第１の電極４１および第２の電極４２と電気的に接続されている。
The other surface of the substrate body 2 is a non-mounting surface 22 on which no light emitting element is mounted, and a pair (the anode side and the cathode side) of external electrode terminals 6 are provided on the non-mounting surface 22. These external electrode terminals 6 are electrically connected to the first electrode 41 and the second electrode 42 provided on the mounting surface of the substrate body 2 through connection vias 7 formed inside the substrate body 2 and the like. It is connected to the.
外部電極端子６および接続ビア７の形状や構成材料としては、通常発光素子搭載用基板に用いられるものと同様のものであれば特に制限なく使用できる。また、外部電極端子６および接続ビア７の配置については、これらと配線導体層４（すなわち、第１の電極４１および第２の電極４２）を介して、搭載される８個の発光素子が電気的に並列接続されるように配置されていればよい。後述する基板の製造方法の項で具体的に説明する。
The shape and constituent materials of the external electrode terminal 6 and the connection via 7 can be used without particular limitation as long as they are the same as those used for a substrate for mounting a light emitting element. Further, regarding the arrangement of the external electrode terminals 6 and the connection vias 7, the eight light emitting elements to be mounted are electrically connected via these and the wiring conductor layer 4 (that is, the first electrode 41 and the second electrode 42). It is only necessary to be arranged so as to be connected in parallel. This will be specifically described in the section of the substrate manufacturing method described later.
また、本実施形態においては、基板本体２の熱抵抗を低減するために、基板本体２の内部にサーマルビア８および放熱層９が埋設されている。サーマルビア８は、例えば発光素子の搭載部Ｔより小さい柱状のものであり、非搭載面２２から内部に埋設された放熱層９にかけて配設するのが好ましい。このような配置とすることで、搭載全体領域２１、特に搭載部Ｔの平坦度を向上でき、熱抵抗を低減し、また発光素子を搭載したときの傾きも抑制できる。サーマルビア８と放熱層９の形状や配置については、後述する基板の製造方法の項で具体的に説明する。
Further, in the present embodiment, in order to reduce the thermal resistance of the substrate body 2, the thermal via 8 and the heat dissipation layer 9 are embedded in the substrate body 2. The thermal via 8 has a columnar shape smaller than the mounting portion T of the light emitting element, for example, and is preferably arranged from the non-mounting surface 22 to the heat radiation layer 9 embedded inside. With such an arrangement, the flatness of the entire mounting area 21, particularly the mounting portion T, can be improved, the thermal resistance can be reduced, and the inclination when the light emitting element is mounted can be suppressed. The shape and arrangement of the thermal via 8 and the heat dissipation layer 9 will be specifically described in the section of the substrate manufacturing method described later.
以上、本発明の発光素子搭載用基板１の実施形態について一例を挙げて説明したが、本発明の発光素子搭載用基板はこれに限定されるものではない。本発明の趣旨に反しない限度において、また必要に応じてその構成を適宜変更できる。
The embodiment of the light emitting element mounting substrate 1 of the present invention has been described above by way of an example, but the light emitting element mounting substrate of the present invention is not limited to this. As long as it does not contradict the spirit of the present invention, the configuration can be changed as necessary.
上記のように構成される本発明の発光素子搭載用基板１の製造においては、発光素子搭載用ＬＴＣＣ基板に通常用いられる材料および製造方法が適用できる。また、後述する本発明の発光装置についても、本発明の発光素子搭載用基板１を用いる以外は、通常の部材を用いて通常の方法で製造できる。
In the manufacture of the light emitting element mounting substrate 1 of the present invention configured as described above, materials and manufacturing methods generally used for the light emitting element mounting LTCC substrate can be applied. Moreover, the light emitting device of the present invention described later can also be manufactured by a normal method using a normal member except that the light emitting element mounting substrate 1 of the present invention is used.
以下に、２ワイヤタイプの発光素子を８個、電気的に並列接続して搭載するための、図１～図３に示される基板を製造する方法を例にして、本発明の発光素子搭載用基板の製造方法を説明する。
In the following, the method for manufacturing the substrate shown in FIGS. 1 to 3 for mounting eight 2-wire type light emitting elements in electrical parallel connection will be described as an example. A method for manufacturing the substrate will be described.
図１～図３に示す発光素子搭載用基板１は、以下の（Ａ）～（Ｅ）の各工程を含む製造方法により製造できる。なお、以下の説明では、その製造に用いる部材、形成材料層等について、完成品の部材と同一の符号を付して説明する。例えば、オーバーコート層とオーバーコートガラスペースト層とは、５の符号をもって表記し、他も同様とする。
The light emitting element mounting substrate 1 shown in FIGS. 1 to 3 can be manufactured by a manufacturing method including the following steps (A) to (E). In the following description, members, forming material layers, and the like used in the manufacture will be described with the same reference numerals as those of the finished product. For example, the overcoat layer and the overcoat glass paste layer are denoted by a symbol of 5, and the others are the same.
（Ａ）本体用グリーンシート作製工程
ガラス粉末とセラミックス粉末とを含むガラスセラミックス組成物を用いて、発光素子搭載用基板の基板本体を形成するためのグリーンシート（本体用グリーンシート）および枠体を形成するために枠体用グリーンシートを作製する。なお、後述するように、本体用グリーンシートは、上層を形成するための上層用グリーンシート、内層を形成するための内層用グリーンシート、下層を形成するための下層用グリーンシートを含む。 (A) Green sheet manufacturing process for main body A green sheet (green sheet for main body) and a frame for forming a substrate main body of a light emitting element mounting substrate using a glass ceramic composition including glass powder and ceramic powder. A green sheet for a frame is prepared for formation. As described later, the main body green sheet includes an upper layer green sheet for forming an upper layer, an inner layer green sheet for forming an inner layer, and a lower layer green sheet for forming a lower layer.
ガラス粉末とセラミックス粉末とを含むガラスセラミックス組成物を用いて、発光素子搭載用基板の基板本体を形成するためのグリーンシート（本体用グリーンシート）および枠体を形成するために枠体用グリーンシートを作製する。なお、後述するように、本体用グリーンシートは、上層を形成するための上層用グリーンシート、内層を形成するための内層用グリーンシート、下層を形成するための下層用グリーンシートを含む。 (A) Green sheet manufacturing process for main body A green sheet (green sheet for main body) and a frame for forming a substrate main body of a light emitting element mounting substrate using a glass ceramic composition including glass powder and ceramic powder. A green sheet for a frame is prepared for formation. As described later, the main body green sheet includes an upper layer green sheet for forming an upper layer, an inner layer green sheet for forming an inner layer, and a lower layer green sheet for forming a lower layer.
（Ｂ）導体ペースト層形成工程
各本体用グリーンシートの所定の位置に導体ペースト層を形成することにより、未焼成配線導体層、未焼成外部電極端子、未焼成接続ビア、未焼成サーマルビア、未焼成放熱層等をそれぞれ形成する。 (B) Conductive paste layer forming step By forming a conductive paste layer at a predetermined position on each main body green sheet, an unfired wiring conductor layer, an unfired external electrode terminal, an unfired connection via, an unfired thermal via, A fired heat dissipation layer or the like is formed.
各本体用グリーンシートの所定の位置に導体ペースト層を形成することにより、未焼成配線導体層、未焼成外部電極端子、未焼成接続ビア、未焼成サーマルビア、未焼成放熱層等をそれぞれ形成する。 (B) Conductive paste layer forming step By forming a conductive paste layer at a predetermined position on each main body green sheet, an unfired wiring conductor layer, an unfired external electrode terminal, an unfired connection via, an unfired thermal via, A fired heat dissipation layer or the like is formed.
（Ｃ）オーバーコートガラスペースト層形成工程
上層用グリーンシートにおいて、搭載可能領域のほぼ全域を覆うように、オーバーコートガラスペースト層を形成する。 (C) Overcoat glass paste layer forming step In the upper layer green sheet, an overcoat glass paste layer is formed so as to cover almost the entire mountable region.
上層用グリーンシートにおいて、搭載可能領域のほぼ全域を覆うように、オーバーコートガラスペースト層を形成する。 (C) Overcoat glass paste layer forming step In the upper layer green sheet, an overcoat glass paste layer is formed so as to cover almost the entire mountable region.
（Ｄ）積層工程
本体用グリーンシートに導体ペースト層（上層用グリーンシートにおいてはさらにオーバーコートガラスペースト層）が形成されて得られた複数枚の未焼成本体部材（以下、導体ペースト層付きグリーンシート、およびオーバーコートガラスペースト層付きグリーンシートともいう。）等を重ね合わせ、熱圧着により一体化して未焼成基板を得る。 (D) Lamination process A plurality of unfired main body members (hereinafter referred to as green sheets with a conductive paste layer) obtained by forming a conductive paste layer (in addition, an overcoat glass paste layer in the upper green sheet) on the green sheet for the main body. , And a green sheet with an overcoat glass paste layer) and the like are overlapped and integrated by thermocompression bonding to obtain a green substrate.
本体用グリーンシートに導体ペースト層（上層用グリーンシートにおいてはさらにオーバーコートガラスペースト層）が形成されて得られた複数枚の未焼成本体部材（以下、導体ペースト層付きグリーンシート、およびオーバーコートガラスペースト層付きグリーンシートともいう。）等を重ね合わせ、熱圧着により一体化して未焼成基板を得る。 (D) Lamination process A plurality of unfired main body members (hereinafter referred to as green sheets with a conductive paste layer) obtained by forming a conductive paste layer (in addition, an overcoat glass paste layer in the upper green sheet) on the green sheet for the main body. , And a green sheet with an overcoat glass paste layer) and the like are overlapped and integrated by thermocompression bonding to obtain a green substrate.
（Ｅ）焼成工程
前記未焼成基板を８００～９３０℃で焼成する。 (E) Firing step The unfired substrate is fired at 800 to 930 ° C.
前記未焼成基板を８００～９３０℃で焼成する。 (E) Firing step The unfired substrate is fired at 800 to 930 ° C.
以下、各工程についてさらに説明する。
Hereinafter, each process will be further described.
（Ａ）本体用グリーンシート作製工程
本体用グリーンシートは、ガラス粉末とセラミックス粉末とを含むガラスセラミックス組成物に、バインダー、必要に応じて可塑剤、分散剤、溶剤等を添加してスラリーを調製し、これをドクターブレード法等によりシート状に成形し、乾燥させることで製造できる。また、こうして作製されたグリーンシートを、所定の形状に加工することにより、枠体用グリーンシートが得られる。 (A) Green sheet production process for main body A green sheet for main body is prepared by adding a binder, and if necessary, a plasticizer, a dispersant, a solvent, etc. to a glass ceramic composition containing glass powder and ceramic powder. Then, it can be produced by forming it into a sheet by the doctor blade method and drying it. Moreover, the green sheet for a frame is obtained by processing the green sheet thus produced into a predetermined shape.
本体用グリーンシートは、ガラス粉末とセラミックス粉末とを含むガラスセラミックス組成物に、バインダー、必要に応じて可塑剤、分散剤、溶剤等を添加してスラリーを調製し、これをドクターブレード法等によりシート状に成形し、乾燥させることで製造できる。また、こうして作製されたグリーンシートを、所定の形状に加工することにより、枠体用グリーンシートが得られる。 (A) Green sheet production process for main body A green sheet for main body is prepared by adding a binder, and if necessary, a plasticizer, a dispersant, a solvent, etc. to a glass ceramic composition containing glass powder and ceramic powder. Then, it can be produced by forming it into a sheet by the doctor blade method and drying it. Moreover, the green sheet for a frame is obtained by processing the green sheet thus produced into a predetermined shape.
本体用グリーンシートを作製するための本体用ガラス粉末としては、ガラス転移点（Ｔｇ）が５５０℃以上７００℃以下のものが好ましい。Ｔｇが５５０℃未満の場合には、脱脂が困難となるおそれがあり、７００℃を超える場合には、収縮開始温度が高くなり、寸法精度が低下するおそれがある。
The glass powder for main body for producing the green sheet for main body preferably has a glass transition point (Tg) of 550 ° C. or higher and 700 ° C. or lower. When Tg is less than 550 ° C., degreasing may be difficult, and when it exceeds 700 ° C., the shrinkage start temperature becomes high and the dimensional accuracy may be lowered.
また、このガラス粉末は、８００℃以上９３０℃以下で焼成したときに結晶が析出するものであることが好ましい。結晶が析出しないものの場合、十分な機械的強度を得ることができないおそれがある。さらに、ＤＴＡ（示差熱分析）により測定される結晶化ピーク温度（Ｔｃ）が８８０℃以下のものが好ましい。Ｔｃが８８０℃を超える場合、寸法精度が低下するおそれがある。
Further, it is preferable that the glass powder is one in which crystals are precipitated when fired at 800 ° C. or higher and 930 ° C. or lower. In the case where crystals do not precipitate, there is a possibility that sufficient mechanical strength cannot be obtained. Furthermore, the thing whose crystallization peak temperature (Tc) measured by DTA (differential thermal analysis) is 880 degrees C or less is preferable. When Tc exceeds 880 ° C., the dimensional accuracy may be reduced.
このような本体用ガラス粉末としては、下記酸化物基準のモル％表示で、ＳｉＯ２を５７～６５％、Ｂ２Ｏ３を１３～１８％、ＣａＯを９～２３％、Ａｌ２Ｏ３を３～８％、Ｋ２ＯおよびＮａ２Ｏから選ばれる少なくとも一方を合計で０．５～６％含有するものが好ましい。このような組成のガラスを用いることで、基板本体２の表面平坦度を向上させることが容易となる。
As such glass powder for main body, SiO 2 is 57 to 65%, B 2 O 3 is 13 to 18%, CaO is 9 to 23%, and Al 2 O 3 is expressed in mol% on the basis of the following oxides. It preferably contains 3 to 8% and at least one selected from K 2 O and Na 2 O in a total amount of 0.5 to 6%. By using the glass having such a composition, it becomes easy to improve the surface flatness of the substrate body 2.
ここで、ＳｉＯ２は、ガラスのネットワークフォーマとなるものである。ＳｉＯ２の含有量が５７％未満の場合、安定なガラスを得ることが難しく、また化学的耐久性も低下するおそれがある。一方、ＳｉＯ２の含有量が６５％を超える場合には、ガラス溶融温度やＴｇが過度に高くなるおそれがある。ＳｉＯ２の含有量は、好ましくは５８％以上、より好ましくは５９％以上、特に好ましくは６０％以上である。また、ＳｉＯ２の含有量は、好ましくは６４％以下、より好ましくは６３％以下である。
Here, SiO 2 serves as a glass network former. When the content of SiO 2 is less than 57%, it is difficult to obtain a stable glass and the chemical durability may be lowered. On the other hand, when the content of SiO 2 exceeds 65%, the glass melting temperature and Tg may be excessively increased. The content of SiO 2 is preferably 58% or more, more preferably 59% or more, and particularly preferably 60% or more. Further, the content of SiO 2 is preferably 64% or less, more preferably 63% or less.
Ｂ２Ｏ３は、ガラスのネットワークフォーマとなるものである。Ｂ２Ｏ３の含有量が１３％未満の場合、ガラス溶融温度やＴｇが過度に高くなるおそれがある。一方、Ｂ２Ｏ３の含有量が１８％を超える場合、安定なガラスを得ることが難しく、また化学的耐久性も低下するおそれがある。Ｂ２Ｏ３の含有量は、好ましくは１４％以上、より好ましくは１５％以上である。また、Ｂ２Ｏ３の含有量は、好ましくは１７％以下、より好ましくは１６％以下である。
B 2 O 3 is a glass network former. If the content of B 2 O 3 is less than 13%, there is a possibility that the glass melting temperature or Tg may be too high. On the other hand, when the content of B 2 O 3 exceeds 18%, it is difficult to obtain a stable glass, and the chemical durability may be lowered. The content of B 2 O 3 is preferably 14% or more, more preferably 15% or more. Further, the content of B 2 O 3 is preferably 17% or less, more preferably 16% or less.
Ａｌ２Ｏ３は、ガラスの安定性、化学的耐久性、および強度を高めるために添加される。Ａｌ２Ｏ３の含有量が３％未満の場合、ガラスが不安定となるおそれがある。一方、Ａｌ２Ｏ３の含有量が８％を超える場合、ガラス溶融温度やＴｇが過度に高くなるおそれがある。Ａｌ２Ｏ３の含有量は、好ましくは４％以上、より好ましくは５％以上である。また、Ａｌ２Ｏ３の含有量は、好ましくは７％以下、より好ましくは６％以下である。
Al 2 O 3 is added to increase the stability, chemical durability, and strength of the glass. If the content of Al 2 O 3 is less than 3%, the glass may become unstable. On the other hand, when the content of Al 2 O 3 exceeds 8%, the glass melting temperature and Tg may be excessively high. The content of Al 2 O 3 is preferably 4% or more, more preferably 5% or more. Further, the content of Al 2 O 3 is preferably 7% or less, more preferably 6% or less.
ＣａＯは、ガラスの安定性や結晶の析出性を高めるとともに、ガラス溶融温度やＴｇを低下させるために添加される。ＣａＯの含有量が９％未満の場合、ガラス溶融温度が過度に高くなるおそれがある。一方、ＣａＯの含有量が２３％を超える場合、ガラスが不安定になるおそれがある。ＣａＯの含有量は、好ましくは１２％以上、より好ましくは１３％以上、特に好ましくは１４％以上である。また、ＣａＯの含有量は、好ましくは２２％以下、より好ましくは２１％以下、特に好ましくは２０％以下である。
CaO is added to increase glass stability and crystal precipitation, and to lower the glass melting temperature and Tg. When the content of CaO is less than 9%, the glass melting temperature may be excessively high. On the other hand, when the content of CaO exceeds 23%, the glass may become unstable. The content of CaO is preferably 12% or more, more preferably 13% or more, and particularly preferably 14% or more. Further, the content of CaO is preferably 22% or less, more preferably 21% or less, and particularly preferably 20% or less.
Ｋ２Ｏ、Ｎａ２Ｏは、Ｔｇを低下させるために添加される。Ｋ２ＯおよびＮａ２Ｏの合計した含有量が０．５％未満の場合、ガラス溶融温度やＴｇが過度に高くなるおそれがある。一方、Ｋ２ＯおよびＮａ２Ｏの合計した含有量が６％を超える場合、化学的耐久性、特に耐酸性が低下するおそれがあり、電気的絶縁性も低下するおそれがある。Ｋ２ＯおよびＮａ２Ｏの合計した含有量は、０．８％以上５％以下であることが好ましい。
K 2 O and Na 2 O are added to lower Tg. When the total content of K 2 O and Na 2 O is less than 0.5%, the glass melting temperature and Tg may be excessively high. On the other hand, when the total content of K 2 O and Na 2 O exceeds 6%, chemical durability, particularly acid resistance may be lowered, and electrical insulation may be lowered. The total content of K 2 O and Na 2 O is preferably 0.8% or more and 5% or less.
なお、本体用ガラス粉末は、必ずしも上記成分のみからなるものに限定されず、Ｔｇ等の諸特性を満たす範囲で他の成分を含有することができる。他の成分を含有する場合、その合計した含有量は１０％以下であることが好ましい。
In addition, the glass powder for main bodies is not necessarily limited to what consists only of the said component, Other components can be contained in the range with which various characteristics, such as Tg, are satisfy | filled. When other components are contained, the total content is preferably 10% or less.
本体用ガラス粉末は、上記したような組成を有するガラスを溶融法によって製造し、乾式粉砕法や湿式粉砕法によって粉砕して得られる。湿式粉砕法の場合、溶媒として水またはエチルアルコールを用いることが好ましい。粉砕機としては、例えばロールミル、ボールミル、ジェットミル等が挙げられる。
The glass powder for main body is obtained by manufacturing glass having the above composition by a melting method and pulverizing it by a dry pulverization method or a wet pulverization method. In the case of the wet pulverization method, it is preferable to use water or ethyl alcohol as a solvent. Examples of the pulverizer include a roll mill, a ball mill, and a jet mill.
本体用ガラス粉末の５０％粒径（Ｄ５０）は０．５μｍ以上２μｍ以下であることが好ましい。ガラス粉末のＤ５０が０．５μｍ未満の場合、ガラス粉末が凝集しやすくなり、取り扱いが困難になるばかりでなく、均一分散が困難になる。一方、ガラス粉末のＤ５０が２μｍを超える場合には、ガラス軟化温度の上昇や焼結不足が発生するおそれがある。粒径は、例えば粉砕後に必要に応じて分級して調整してもよい。
The 50% particle size (D 50 ) of the glass powder for main body is preferably 0.5 μm or more and 2 μm or less. If D 50 of the glass powder is less than 0.5 [mu] m, it glass powder is likely to agglomerate, handle not only difficult, uniform dispersion becomes difficult. On the other hand, if the D 50 of the glass powder exceeds 2μm, there is a possibility that increase and insufficient sintering of the glass softening temperature is generated. The particle diameter may be adjusted by classification as necessary after pulverization, for example.
セラミックス粉末としては、従来からＬＴＣＣ基板の製造に用いられるものが使用でき、例えばアルミナ粉末、ジルコニア粉末、またはアルミナ粉末とジルコニア粉末との混合物等を好適に使用できる。特に、アルミナ粉末とともに、アルミナよりも高い屈折率を有するセラミックスの粉末（以下、高屈折率セラミックス粉末と示す。）を使用することが好ましい。
As the ceramic powder, those conventionally used for the production of LTCC substrates can be used. For example, alumina powder, zirconia powder, or a mixture of alumina powder and zirconia powder can be suitably used. In particular, it is preferable to use a ceramic powder (hereinafter referred to as a high refractive index ceramic powder) having a higher refractive index than alumina together with the alumina powder.
高屈折率セラミックス粉末は、下記する焼成工程により焼結して得られた基体本体の反射率を向上させるための成分であり、例えばチタニア粉末、ジルコニア粉末、安定化ジルコニア粉末、酸化亜鉛粉末、チタン酸バリウム粉末、チタン酸鉛粉末等が挙げられる。例えば、アルミナの屈折率が１．８程度であるのに対して、チタニアの屈折率は２．７程度、ジルコニアの屈折率は２．２程度であり、アルミナに比べて高い屈折率を有している。これらのセラミックスの粉末のＤ５０は、０．５μｍ以上４μｍ以下であることが好ましい。
The high refractive index ceramic powder is a component for improving the reflectivity of the base body obtained by sintering by the firing process described below. For example, titania powder, zirconia powder, stabilized zirconia powder, zinc oxide powder, titanium Examples thereof include barium acid powder and lead titanate powder. For example, the refractive index of alumina is about 1.8, while the refractive index of titania is about 2.7 and the refractive index of zirconia is about 2.2, which is higher than that of alumina. ing. D 50 of these ceramic powders is preferably 0.5 μm or more and 4 μm or less.
このようなガラス粉末とセラミックス粉末とを、例えばガラス粉末が３０質量％以上５０質量％以下、セラミックス粉末が５０質量％以上７０質量％以下となるように配合し、混合することにより、ガラスセラミックス組成物が得られる。また、このガラスセラミックス組成物に、バインダー、必要に応じて可塑剤、分散剤、溶剤等を添加することにより所望のスラリーが得られる。
By mixing and mixing such glass powder and ceramic powder such that the glass powder is 30% by mass to 50% by mass and the ceramic powder is 50% by mass to 70% by mass, the glass ceramic composition is mixed. Things are obtained. Moreover, a desired slurry can be obtained by adding a binder and, if necessary, a plasticizer, a dispersant, a solvent, and the like to the glass ceramic composition.
バインダーとしては、例えばポリビニルブチラール、アクリル樹脂等を好適に使用できる。可塑剤としては、例えばフタル酸ジブチル、フタル酸ジオクチル、フタル酸ブチルベンジル等を使用できる。溶剤としては、トルエン、キシレン、２－プロパノール、２－ブタノール等の有機溶剤を好適に使用できる。
As the binder, for example, polyvinyl butyral, acrylic resin or the like can be suitably used. As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate and the like can be used. As the solvent, organic solvents such as toluene, xylene, 2-propanol and 2-butanol can be preferably used.
このようにして得られたスラリーをドクターブレード法等によりシート状に成形し、乾燥させて、３枚の本体用グリーンシート（上層用グリーンシート、下層用グリーンシートおよび内層用グリーンシート）を作製する。また、同様にして製造されたグリーンシートを、所定の形状に加工することにより、枠体用グリーンシートを作製する。
The slurry thus obtained is formed into a sheet by a doctor blade method or the like and dried to produce three green sheets for the main body (upper layer green sheet, lower layer green sheet and inner layer green sheet). . In addition, a green sheet for a frame is manufactured by processing the green sheet manufactured in the same manner into a predetermined shape.
（Ｂ）導体ペースト層形成工程
前記工程で作製された本体用グリーンシートの表面および内部に、配線導体層、外部電極端子、接続ビア、サーマルビア、放熱層等を形成するための導体ペースト層を形成する。すなわち、図４に示すように、上層用グリーンシート２３において、素子搭載面に相当する搭載全体領域２１の中央に、円形の第１の電極用導体ペースト層４１を形成する。 (B) Conductive paste layer forming step A conductive paste layer for forming a wiring conductive layer, external electrode terminals, connection vias, thermal vias, heat dissipation layers, etc. on the surface and inside of the green sheet for main body produced in the above step. Form. That is, as shown in FIG. 4, a circular first electrodeconductor paste layer 41 is formed in the center of the entire mounting area 21 corresponding to the element mounting surface in the upper layer green sheet 23.
前記工程で作製された本体用グリーンシートの表面および内部に、配線導体層、外部電極端子、接続ビア、サーマルビア、放熱層等を形成するための導体ペースト層を形成する。すなわち、図４に示すように、上層用グリーンシート２３において、素子搭載面に相当する搭載全体領域２１の中央に、円形の第１の電極用導体ペースト層４１を形成する。 (B) Conductive paste layer forming step A conductive paste layer for forming a wiring conductive layer, external electrode terminals, connection vias, thermal vias, heat dissipation layers, etc. on the surface and inside of the green sheet for main body produced in the above step. Form. That is, as shown in FIG. 4, a circular first electrode
また、この第１の電極用導体ペースト層４１を囲むようにリング状の連結用導体ペースト層４３を形成するとともに、８個の第２の電極用導体ペースト層４２を、連結用導体ペースト層４３から内側に延出するように略等間隔で形成する。さらに、第１の電極用導体ペースト層４１の中心部、および連結用導体ペースト層４３の所定の位置に、接続ビア用導体ペースト層７を上層用グリーンシート２３を貫通して形成する。
In addition, a ring-shaped connecting conductor paste layer 43 is formed so as to surround the first electrode conductor paste layer 41, and the eight second electrode conductor paste layers 42 are connected to the connecting conductor paste layer 43. It is formed at substantially equal intervals so as to extend inward from the inside. Further, the connection via conductor paste layer 7 is formed through the upper layer green sheet 23 at a predetermined position of the central portion of the first electrode conductor paste layer 41 and the connecting conductor paste layer 43.
また、図５に示すように、内層用グリーンシート２４において、その上面に、放熱層用導体ペースト層９を形成するとともに、このグリーンシートを貫通するように、複数の接続ビア用導体ペースト層７と複数のサーマルビア用導体ペースト層８を形成する。
Further, as shown in FIG. 5, in the inner layer green sheet 24, a heat dissipating layer conductor paste layer 9 is formed on the upper surface thereof, and a plurality of connection via conductor paste layers 7 are formed so as to penetrate the green sheet. A plurality of conductor paste layers 8 for thermal vias are formed.
さらに、図６に示すように、下層用グリーンシート２５を貫通するように、複数の接続ビア用導体ペースト層７と複数のサーマルビア用導体ペースト層８を形成するとともに、下層用グリーンシート２５の下面に、外部電極端子用導体ペースト層６を形成する。なお、各グリーンシートには、多数の発光装置に対応する多数の領域が形成され、これらが最終の焼成工程の後に分割されるが、図４～図６では、１個の発光装置に対応する一つ発光素子搭載用基板を形成するための領域を示すものとする。
Further, as shown in FIG. 6, a plurality of connection via conductor paste layers 7 and a plurality of thermal via conductor paste layers 8 are formed so as to penetrate the lower layer green sheet 25, and A conductor paste layer 6 for external electrode terminals is formed on the lower surface. Each green sheet is formed with a large number of regions corresponding to a large number of light emitting devices, and these are divided after the final baking step, but in FIGS. 4 to 6, they correspond to a single light emitting device. An area for forming one light emitting element mounting substrate is shown.
第１および第２の電極用導体ペースト層４１、４２、連結用導体ペースト層４３、接続ビア用導体ペースト層７、放熱層用導体ペースト層９、サーマルビア用導体ペースト層８、および外部電極端子用導体ペースト層６の形成方法としては、導体ペーストをスクリーン印刷により塗布、充填する方法が挙げられる。形成されるこれらの導体ペースト層の膜厚は、最終的に得られる第１および第２の電極、連結配線、接続ビア、放熱層、サーマルビアおよび外部電極端子の膜厚が所定の膜厚となるように調整される。
First and second electrode conductor paste layers 41 and 42, a connecting conductor paste layer 43, a connection via conductor paste layer 7, a heat dissipation layer conductor paste layer 9, a thermal via conductor paste layer 8, and an external electrode terminal Examples of the method for forming the conductive paste layer 6 include a method of applying and filling the conductive paste by screen printing. The thickness of these formed conductive paste layers is such that the first and second electrodes, connection wirings, connection vias, heat dissipation layers, thermal vias, and external electrode terminals finally obtained have a predetermined thickness. It is adjusted to become.
導体ペーストとしては、例えば銅、銀、金等を主成分とする金属の粉末に、エチルセルロース等のビヒクル、必要に応じて溶剤等を添加してペースト状としたものを使用できる。なお、上記金属粉末としては、銀粉末、銀と白金からなる金属粉末、または銀とパラジウムからなる金属粉末が好ましく用いられる。
As the conductive paste, for example, a paste obtained by adding a vehicle such as ethyl cellulose to a metal powder mainly composed of copper, silver, gold or the like, and a solvent or the like as required can be used. As the metal powder, silver powder, metal powder composed of silver and platinum, or metal powder composed of silver and palladium are preferably used.
（Ｃ）オーバーコートガラスペースト層形成工程
上層用グリーンシートにおいて、（Ｂ）工程で形成された配線導体ペースト層４の周囲近傍を除き搭載可能領域のほぼ全域を覆うように、スクリーン印刷によりオーバーコートガラスペースト層５を形成する。 (C) Overcoat glass paste layer forming step In the upper layer green sheet, overcoat is applied by screen printing so as to cover almost the entire mountable region except for the vicinity of the wiringconductor paste layer 4 formed in the step (B). A glass paste layer 5 is formed.
上層用グリーンシートにおいて、（Ｂ）工程で形成された配線導体ペースト層４の周囲近傍を除き搭載可能領域のほぼ全域を覆うように、スクリーン印刷によりオーバーコートガラスペースト層５を形成する。 (C) Overcoat glass paste layer forming step In the upper layer green sheet, overcoat is applied by screen printing so as to cover almost the entire mountable region except for the vicinity of the wiring
オーバーコートガラスペーストは、前記したオーバーコート層用のガラス粉末と、必要に応じて前記セラミックス粉末とを混合してなる組成物に、エチルセルロース等のビヒクル、必要に応じて溶剤等を添加してペースト状としたものを用いることができる。形成されるオーバーコートガラスペースト層５の膜厚は、最終的に得られるオーバーコート層５の厚さが、基板本体２の搭載可能領域の表面粗さＲａの３～２０倍の厚さとなり、かつこのオーバーコート層５の表面粗さＲａが０．１５μｍ以下となるように調整される。オーバーコート層５の表面粗さＲａの調整は、オーバーコート層５の厚さだけでなく、オーバーコート層用のガラス粉末の粒径や組成およびペーストの混練方法と混練時間によっても行うことができる。すなわち、オーバーコート層用ガラス粉末として、焼成時に十分に溶融する流動性に優れる組成および粒径のものを使用し、さらにセラミックス粉末との混合物の組成を焼成時に流動性に優れたものとし、その混練方法と時間を最適化することにより、オーバーコート層５の表面粗さＲａを小さくできる。
例えば、基板本体２の搭載可能領域の表面粗さＲａが０．３０～０．３５μｍの場合には、焼成後のオーバーコート層５の厚さは、０．９～７．０μｍとされる。 The overcoat glass paste is a paste prepared by adding a vehicle such as ethyl cellulose to a composition obtained by mixing the glass powder for the overcoat layer and the ceramic powder as necessary, and a solvent as necessary. What was made into a shape can be used. The thickness of the overcoatglass paste layer 5 to be formed is such that the thickness of the finally obtained overcoat layer 5 is 3 to 20 times the surface roughness Ra of the mountable area of the substrate body 2. In addition, the surface roughness Ra of the overcoat layer 5 is adjusted to be 0.15 μm or less. The surface roughness Ra of the overcoat layer 5 can be adjusted not only by the thickness of the overcoat layer 5, but also by the particle size and composition of the glass powder for the overcoat layer, the paste kneading method and the kneading time. . That is, as the glass powder for the overcoat layer, a glass powder having a composition and particle size excellent in fluidity that sufficiently melts during firing is used, and the composition of the mixture with the ceramic powder is excellent in fluidity during firing. By optimizing the kneading method and time, the surface roughness Ra of the overcoat layer 5 can be reduced.
For example, when the surface roughness Ra of the mountable region of thesubstrate body 2 is 0.30 to 0.35 μm, the thickness of the overcoat layer 5 after firing is set to 0.9 to 7.0 μm.
例えば、基板本体２の搭載可能領域の表面粗さＲａが０．３０～０．３５μｍの場合には、焼成後のオーバーコート層５の厚さは、０．９～７．０μｍとされる。 The overcoat glass paste is a paste prepared by adding a vehicle such as ethyl cellulose to a composition obtained by mixing the glass powder for the overcoat layer and the ceramic powder as necessary, and a solvent as necessary. What was made into a shape can be used. The thickness of the overcoat
For example, when the surface roughness Ra of the mountable region of the
（Ｄ）積層工程
前記（Ｂ）工程で得られた導体ペースト層付きグリーンシート（未焼成本体部材）と、前記（Ｃ）工程で得られたオーバーコートガラスペースト層付きグリーンシートを所定の順で重ね合わせ、上層用グリーンシート２３の上にさらに枠体用グリーンシートを重ねた後、熱圧着により一体化する。こうして、未焼成基板が得られる。 (D) Lamination process Green sheet with conductor paste layer (unfired main body member) obtained in step (B) and green sheet with overcoat glass paste layer obtained in step (C) in a predetermined order The green sheet for frame is further stacked on the upper layergreen sheet 23, and then integrated by thermocompression bonding. Thus, an unfired substrate is obtained.
前記（Ｂ）工程で得られた導体ペースト層付きグリーンシート（未焼成本体部材）と、前記（Ｃ）工程で得られたオーバーコートガラスペースト層付きグリーンシートを所定の順で重ね合わせ、上層用グリーンシート２３の上にさらに枠体用グリーンシートを重ねた後、熱圧着により一体化する。こうして、未焼成基板が得られる。 (D) Lamination process Green sheet with conductor paste layer (unfired main body member) obtained in step (B) and green sheet with overcoat glass paste layer obtained in step (C) in a predetermined order The green sheet for frame is further stacked on the upper layer
（Ｅ）焼成工程
上記工程で得られた未焼成基板について、必要に応じてバインダー等を脱脂後、ガラスセラミックス組成物等を焼結させるための焼成を行って発光素子搭載用基板１とする。 (E) Firing process About the unbaked board | substrate obtained at the said process, after degreasing | defatting a binder etc. as needed, the baking for sintering a glass ceramic composition etc. is performed and it is set as the light emittingelement mounting substrate 1. FIG.
上記工程で得られた未焼成基板について、必要に応じてバインダー等を脱脂後、ガラスセラミックス組成物等を焼結させるための焼成を行って発光素子搭載用基板１とする。 (E) Firing process About the unbaked board | substrate obtained at the said process, after degreasing | defatting a binder etc. as needed, the baking for sintering a glass ceramic composition etc. is performed and it is set as the light emitting
前記した脱脂は、例えば５００℃以上６００℃以下の温度で１時間以上１０時間以下保持する条件で行う。脱脂温度が５００℃未満もしくは脱脂時間が１時間未満の場合、バインダー等を十分に除去できないおそれがある。一方、脱脂温度は６００℃程度、脱脂時間は１０時間程度とすれば、バインダー等を十分に除去でき、これを超えるとかえって生産性等が低下するおそれがある。
The above-described degreasing is performed, for example, under the condition of holding at a temperature of 500 ° C. to 600 ° C. for 1 hour to 10 hours. When the degreasing temperature is less than 500 ° C. or the degreasing time is less than 1 hour, the binder or the like may not be sufficiently removed. On the other hand, if the degreasing temperature is about 600 ° C. and the degreasing time is about 10 hours, the binder and the like can be sufficiently removed, and if it exceeds this, productivity and the like may be lowered.
また、焼成は、基体本体２の緻密な構造の獲得と生産性を考慮して、８００℃～９３０℃の温度範囲で適宜時間を調整できる。具体的には、８５０℃以上９００℃以下の温度で２０分以上６０分以下保持することが好ましく、特に８６０℃以上８８０℃以下の温度が好ましい。焼成温度が８００℃未満では、基体本体２が緻密な構造のものとして得られないおそれがある。一方、焼成温度は９３０℃を超えると、基体本体２が変形するなど生産性等が低下するおそれがある。また、上記導体ペーストとして、銀を主成分とする金属粉末を含有する金属ペーストを用いた場合、焼成温度が８８０℃を超えると、過度に軟化するために所定の形状を維持できなくなるおそれがある。
Further, the firing can be appropriately adjusted in a temperature range of 800 ° C. to 930 ° C. in consideration of obtaining a dense structure of the base body 2 and productivity. Specifically, it is preferable to hold at a temperature of 850 ° C. or more and 900 ° C. or less for 20 minutes or more and 60 minutes or less, and a temperature of 860 ° C. or more and 880 ° C. or less is particularly preferable. If the firing temperature is less than 800 ° C., the base body 2 may not be obtained as a dense structure. On the other hand, if the firing temperature exceeds 930 ° C., the productivity may be lowered due to deformation of the base body 2. Further, when a metal paste containing a metal powder containing silver as a main component is used as the conductor paste, if the firing temperature exceeds 880 ° C., there is a risk that the predetermined shape cannot be maintained due to excessive softening. .
このようにして発光素子搭載用基板１が得られるが、焼成後、必要に応じて搭載面に露出した配線導体層４（第１および第２の電極４１、４２）の表面を被覆するように、Ｎｉ／金メッキの２層メッキ等の、通常発光素子搭載用基板１において導体保護用に用いられる導電性保護膜を配設することもできる。
Thus, the light-emitting element mounting substrate 1 is obtained. After firing, the surface of the wiring conductor layer 4 (first and second electrodes 41, 42) exposed on the mounting surface is coated as necessary. It is also possible to dispose a conductive protective film used for protecting the conductor in the light emitting element mounting substrate 1 such as Ni / gold plating two-layer plating.
以上、発光素子搭載用基板１の製造方法について説明したが、枠体用グリーンシートは単一のグリーンシートからなる必要はなく、複数枚のグリーンシートを積層したものであってもよい。また、枠体用グリーンシートを除いた本体用グリーンシートの枚数も、必ずしも３枚である必要はなく、２枚あるいは４枚以上であってもよい。さらに、各部の形成順序等については、発光素子搭載用基板１の製造が可能な限度において適宜変更できる。
Although the method for manufacturing the light emitting element mounting substrate 1 has been described above, the frame green sheet need not be a single green sheet, and may be a laminate of a plurality of green sheets. Further, the number of main body green sheets excluding the frame green sheet is not necessarily three, and may be two or four or more. Further, the order of forming each part can be appropriately changed as long as the light emitting element mounting substrate 1 can be manufactured.
次に、本発明の発光素子搭載用基板１を有する発光素子装置の好ましい実施形態を、図面に基づいて説明する。ただし、本発明の発光装置はこれに限定されるものではない。図７は、本発明の発光装置の一実施形態を上面側から見た平面図であり、図８は、図７の発光装置をＹ－Ｙ’線で切断した断面図である。なお、図７では、樹脂封止層を除いた状態を示す。
Next, a preferred embodiment of a light emitting device having the light emitting device mounting substrate 1 of the present invention will be described with reference to the drawings. However, the light emitting device of the present invention is not limited to this. FIG. 7 is a plan view of an embodiment of the light emitting device of the present invention as viewed from the upper surface side, and FIG. 8 is a cross-sectional view of the light emitting device of FIG. 7 cut along the line Y-Y ′. FIG. 7 shows a state where the resin sealing layer is removed.
本発明の発光装置１０は、上記した本発明の発光素子搭載用基板１と、該発光素子搭載用基板１の前記搭載部に搭載され、かつ一対の電極がそれぞれ所定の配線導体層４（第１の電極４１および第２の電極４２）にワイヤボンディングされて並列に接続された２ワイヤタイプの８個の発光素子（例えば、ＬＥＤ素子）１１を備えている。
The light-emitting device 10 of the present invention is mounted on the above-described light-emitting element mounting substrate 1 of the present invention and the mounting portion of the light-emitting element mounting substrate 1, and a pair of electrodes each have a predetermined wiring conductor layer 4 (first 8 light-emitting elements (for example, LED elements) 11 of a two-wire type, which are wire-bonded to one electrode 41 and second electrode 42) and connected in parallel.
本発明の発光装置１０において、８個の発光素子１１は、全て下面が同サイズの正方形である直方体の発光素子であり、発光素子搭載用基板１の前記した８個の搭載部Ｔにそれぞれ配置され、接着剤であるシリコーンダイボンド材（図示せず）を用いて搭載部に固定されている。
In the light emitting device 10 of the present invention, all the eight light emitting elements 11 are rectangular parallelepiped light emitting elements whose bottom surfaces are squares of the same size, and are arranged on the eight mounting portions T of the light emitting element mounting substrate 1, respectively. Then, it is fixed to the mounting portion using a silicone die bond material (not shown) that is an adhesive.
そして、各発光素子１１の電極（図示せず）の一方が、発光素子搭載用基板１の搭載全体領域２１の中央に位置する第２の電極４２に、ボンディングワイヤ１２によって接続されており、他方の電極が８個の第２の電極４２グループのうちで最も近い電極に、ボンディングワイヤ１２によって接続されている。８個の発光素子１１の８対１６個の電極を接続する１６本のボンディングワイヤ１２は、互いに交差しないように配置されている。さらに、これらの発光素子１１やボンディングワイヤ１２を覆うように、モールド樹脂からなる封止層１３が設けられている。
One of the electrodes (not shown) of each light emitting element 11 is connected to the second electrode 42 located at the center of the entire mounting region 21 of the light emitting element mounting substrate 1 by the bonding wire 12, and the other Are connected by the bonding wire 12 to the closest electrode in the group of eight second electrodes 42. The 16 bonding wires 12 connecting the 8 to 16 electrodes of the 8 light emitting elements 11 are arranged so as not to cross each other. Further, a sealing layer 13 made of mold resin is provided so as to cover these light emitting elements 11 and bonding wires 12.
本発明の発光装置１０における発光素子１１の配置は、少なくとも発光素子１１の電極と発光素子搭載用基板１の配線導体層４（第１の電極４１および第２の電極４２）を接続した際に、ボンディングワイヤ１２が交差しない配置であればよく、図７に示す配置に限定されない。
The arrangement of the light emitting element 11 in the light emitting device 10 of the present invention is such that at least the electrode of the light emitting element 11 and the wiring conductor layer 4 (first electrode 41 and second electrode 42) of the light emitting element mounting substrate 1 are connected. As long as the bonding wires 12 do not cross each other, the arrangement is not limited to the arrangement shown in FIG.
本発明の発光装置１０によれば、基板本体２の搭載面に、該搭載面の表面粗さＲａの３～２０倍の厚さのオーバーコート層５が形成され、オーバーコート層５の表面粗さＲａが０．１５μｍ以下になるように構成された発光素子搭載用基板１が使用されているので、発光素子１１から基板本体２への熱放散性に優れており、光取り出し効率に優れ高輝度の発光が可能である。このような発光装置１０は、例えば携帯電話や大型液晶ディスプレイ等のバックライト、自動車用あるいは装飾用の照明、その他の光源として好適に使用できる。
According to the light emitting device 10 of the present invention, the overcoat layer 5 having a thickness 3 to 20 times the surface roughness Ra of the mounting surface is formed on the mounting surface of the substrate body 2. Since the light emitting element mounting substrate 1 having a thickness Ra of 0.15 μm or less is used, the heat dissipation from the light emitting element 11 to the substrate body 2 is excellent, and the light extraction efficiency is excellent. Luminous light emission is possible. Such a light emitting device 10 can be suitably used, for example, as a backlight for a mobile phone, a large-sized liquid crystal display, etc., illumination for automobiles or decoration, and other light sources.
次に、本発明の具体的な実施例を記載する。なお、本発明はこれらの実施例に限定されるものではない。
Next, specific examples of the present invention will be described. The present invention is not limited to these examples.
実施例１～３、比較例１，２
以下に示す方法で、図１～図６に示すような発光素子搭載用基板、図７および図８に示す発光装置を製造した。 Examples 1 to 3, Comparative Examples 1 and 2
The light emitting element mounting substrate as shown in FIGS. 1 to 6 and the light emitting device shown in FIGS. 7 and 8 were manufactured by the following method.
以下に示す方法で、図１～図６に示すような発光素子搭載用基板、図７および図８に示す発光装置を製造した。 Examples 1 to 3, Comparative Examples 1 and 2
The light emitting element mounting substrate as shown in FIGS. 1 to 6 and the light emitting device shown in FIGS. 7 and 8 were manufactured by the following method.
まず、発光素子搭載用基板１の基板本体２を作製するための本体用グリーンシート（上層用グリーンシート、下層用グリーンシート、および内層用グリーンシート）を作製した。本体用グリーンシートの作製においては、酸化物基準のモル％表示で、ＳｉＯ２が６０．４％、Ｂ２Ｏ３が１５．６％、Ａｌ２Ｏ３が６％、ＣａＯが１５％、Ｋ２Ｏが１％、Ｎａ２Ｏが２％となるように原料を配合、混合し、この原料混合物を白金ルツボに入れて１６００℃で６０分間溶融させた後、溶融状態のガラスを流し出し冷却した。このガラスをアルミナ製ボールミルにより４０時間粉砕して本体用ガラス粉末を製造した。なお、粉砕時の溶媒にはエチルアルコールを用いた。
First, main body green sheets (upper layer green sheet, lower layer green sheet, and inner layer green sheet) for manufacturing the substrate body 2 of the light emitting element mounting substrate 1 were manufactured. In the production of the green sheet for the main body, in terms of mol% based on oxide, SiO 2 is 60.4%, B 2 O 3 is 15.6%, Al 2 O 3 is 6%, CaO is 15%, K The raw materials were blended and mixed so that 2 O was 1% and Na 2 O was 2%. The raw material mixture was put in a platinum crucible and melted at 1600 ° C. for 60 minutes, and then the molten glass was poured out and cooled. did. This glass was pulverized with an alumina ball mill for 40 hours to produce a glass powder for a main body. In addition, ethyl alcohol was used as a solvent for pulverization.
次いで、このガラス粉末が３８質量％、アルミナフィラー（昭和電工社製、商品名：ＡＬ－４５Ｈ）が３８質量％、ジルコニアフィラー（第一稀元素化学工業社製、商品名：ＨＳＹ－３Ｆ－Ｊ）が２４質量％となるように配合し、混合することにより、基板本体用のガラスセラミックス組成物を製造した。このガラスセラミックス組成物５０ｇに、有機溶剤（トルエン、キシレン、２－プロパノール、２－ブタノールを質量比４：２：２：１で混合したもの）１５ｇ、可塑剤（フタル酸ジ－２－エチルヘキシル）２．５ｇ、バインダーとしてのポリビニルブチラール（デンカ社製、商品名：ＰＶＫ＃３０００Ｋ）５ｇ、さらに分散剤（ビックケミー社製、商品名：ＢＹＫ１８０）０．５ｇを配合し、混合してスラリーを調製した。
Next, the glass powder was 38% by mass, the alumina filler (manufactured by Showa Denko KK, trade name: AL-45H) was 38% by mass, the zirconia filler (manufactured by Daiichi Rare Element Chemical Industries, trade name: HSY-3F-J). ) Was mixed so as to be 24% by mass, and mixed to produce a glass ceramic composition for a substrate body. 50 g of this glass ceramic composition, 15 g of an organic solvent (mixed with toluene, xylene, 2-propanol, 2-butanol in a mass ratio of 4: 2: 2: 1), a plasticizer (di-2-ethylhexyl phthalate) 2.5 g of polyvinyl butyral (trade name: PVK # 3000K, manufactured by Denka Co., Ltd.) as a binder, 5 g, and 0.5 g of a dispersant (trade name: BYK180, manufactured by Big Chemie) were blended and mixed to prepare a slurry. .
このスラリーをＰＥＴフィルム上にドクターブレード法により塗布し、乾燥させたグリーンシートを焼成後の厚さが０．５ｍｍになるように積層し、本体用グリーンシートを製造した。また、本体用グリーンシートと同様にして製造されたグリーンシートを、所定の形状に加工することにより枠体用グリーンシートを作製した。
This slurry was applied onto a PET film by a doctor blade method, and the dried green sheets were laminated so that the thickness after firing was 0.5 mm to produce a green sheet for a main body. Further, a green sheet for a frame was manufactured by processing a green sheet manufactured in the same manner as the green sheet for a main body into a predetermined shape.
一方、導電性金属粉末（銀粉末、大研化学工業社製、商品名：Ｓ５５０）、ビヒクルとしてのエチルセルロースを質量比８５：１５の割合で配合し、固形分が８５質量％となるように溶剤としてのαテレピネオールに分散後、磁器乳鉢中で１時間混練し、さらに三本ロールにて３回分散して金属ペースト（導体ペースト）を製造した。
On the other hand, conductive metal powder (silver powder, manufactured by Daiken Chemical Industry Co., Ltd., trade name: S550) and ethyl cellulose as a vehicle are blended at a mass ratio of 85:15, and the solvent is set so that the solid content is 85 mass%. After being dispersed in α-terpineol, the mixture was kneaded in a porcelain mortar for 1 hour, and further dispersed three times with a three roll to produce a metal paste (conductor paste).
本体用グリーンシートのうちの１枚（上層用グリーンシート２３）の上面に、前記導体ペーストを図４に示すパターンでスクリーン印刷することにより、第１の電極用、第２の電極用および連結用の各導体ペースト層４１，４２，４３を形成するとともに、接続ビアに相当する部分に孔空け機を用いて直径０．１５ｍｍの貫通孔を形成し、スクリーン印刷法により導体ペーストを充填して、接続ビア用導体ペースト層７を形成した。
On the upper surface of one of the green sheets for the main body (upper green sheet 23), the conductor paste is screen-printed with the pattern shown in FIG. 4 so that the first electrode, the second electrode, and the connection are used. And forming a through hole having a diameter of 0.15 mm using a hole puncher in a portion corresponding to the connection via, and filling the conductor paste by a screen printing method, A connection via conductor paste layer 7 was formed.
また、内層用グリーンシート２４の上面に、導体ペーストを図５に示すパターンでスクリーン印刷することにより、放熱層用導体ペースト層９を形成するとともに、サーマルビア並びに接続ビアに相当する部分に孔空け機を用いて直径０．２ｍｍおよび直径０．１５ｍｍの貫通孔をそれぞれ形成し、スクリーン印刷法により導体ペーストを充填してサーマルビア用導体ペースト層８および接続ビア用導体ペースト層７を形成した。
In addition, the conductor paste layer 9 for the heat radiation layer is formed on the upper surface of the green sheet 24 for the inner layer by screen printing with the pattern shown in FIG. 5, and the portions corresponding to the thermal vias and connection vias are perforated. Through holes having a diameter of 0.2 mm and a diameter of 0.15 mm were formed using a machine, and a conductor paste was filled by a screen printing method to form a thermal via conductor paste layer 8 and a connection via conductor paste layer 7.
さらに、下層用グリーンシート２５の下面に、導体ペーストを図６に示すパターンでスクリーン印刷することにより、外部電極端子用導体ペースト層６を形成するとともに、サーマルビア並びに接続ビアに相当する部分に孔空け機を用いて直径０．２ｍｍおよび直径０．１５ｍｍの貫通孔をそれぞれ形成し、スクリーン印刷法により導体ペーストを充填してサーマルビア用導体ペースト層８および接続ビア用導体ペースト層７を形成した。
Furthermore, the conductor paste layer 6 for external electrode terminals is formed on the lower surface of the lower layer green sheet 25 by screen printing in the pattern shown in FIG. 6, and holes are formed in portions corresponding to the thermal vias and connection vias. Through holes having a diameter of 0.2 mm and a diameter of 0.15 mm were respectively formed using an emptying machine, and a conductive paste was filled by screen printing to form a thermal via conductor paste layer 8 and a connection via conductor paste layer 7. .
次に、実施例１～３および比較例２においては、導体ペースト層が形成された上層用グリーンシート２３の搭載面に、図４に示すパターンでオーバーコートガラスペーストをスクリーン印刷し、オーバーコートガラスペースト層５を形成した。比較例１においては、このようなオーバーコートガラスペースト層５の形成は行わなかった。実施例１～３におけるオーバーコートガラスペースト層５の厚さは、焼成後のオーバーコート層の厚さが、基板本体２の搭載可能領域の表面粗さＲａの３～２０倍の範囲である、表１に示す厚さになるように調整した。また、比較例２におけるオーバーコートガラスペースト層５の厚さは、焼成後のオーバーコート層の厚さが、基板本体２の搭載可能領域の表面粗さＲａの２０倍を超える厚さとなるように調整した。なお、基板本体２の搭載可能領域の表面粗さＲａは、比較例１で得られる発光素子搭載用基板１の搭載面の表面粗さＲａに相当し、その値は後述するように０．３１μｍであった。
Next, in Examples 1 to 3 and Comparative Example 2, the overcoat glass paste was screen-printed in the pattern shown in FIG. 4 on the mounting surface of the upper layer green sheet 23 on which the conductor paste layer was formed. A paste layer 5 was formed. In Comparative Example 1, such overcoat glass paste layer 5 was not formed. The thickness of the overcoat glass paste layer 5 in Examples 1 to 3 is such that the thickness of the overcoat layer after firing is in the range of 3 to 20 times the surface roughness Ra of the mountable region of the substrate body 2. The thickness was adjusted to be as shown in Table 1. Moreover, the thickness of the overcoat glass paste layer 5 in Comparative Example 2 is such that the thickness of the overcoat layer after baking exceeds 20 times the surface roughness Ra of the mountable region of the substrate body 2. It was adjusted. The surface roughness Ra of the mountable area of the substrate body 2 corresponds to the surface roughness Ra of the mounting surface of the light emitting element mounting substrate 1 obtained in Comparative Example 1, and the value is 0.31 μm as will be described later. Met.
オーバーコートガラスペーストは、以下に示すように調製した。まず、酸化物基準のモル％表示で、ＳｉＯ２を８１．６％、Ｂ２Ｏ３を１６．６％、Ｋ２Ｏを１．８％となるように原料を配合、混合し、この原料混合物を白金ルツボに入れて１６００℃で６０分間溶融させた後、溶融状態のガラスを流し出し冷却した。このガラスをアルミナ製ボールミルにより８～６０時間粉砕してオーバーコート用ガラス粉末を製造した。なお、粉砕時の溶媒にはエチルアルコールを用いた。
The overcoat glass paste was prepared as shown below. First, raw materials are blended and mixed so that SiO 2 is 81.6%, B 2 O 3 is 16.6%, and K 2 O is 1.8% in terms of mol% based on oxide. The mixture was put in a platinum crucible and melted at 1600 ° C. for 60 minutes, and then the molten glass was poured out and cooled. This glass was pulverized with an alumina ball mill for 8 to 60 hours to produce an overcoat glass powder. In addition, ethyl alcohol was used as a solvent for pulverization.
次いで、このガラス粉末が９５質量％、シリカ微粉末（日本アエロジル社製、商品名：ＡＥＲＯＳＩＬ３８０、平均粒径７ｎｍ）が５質量％となるように配合し混合した。次いで、得られた混合物が６０質量％、樹脂成分（エチルセルロースとαテレピネオールとを質量比で８５：１５の割合で含有するもの）が４０質量％となるように配合した。そして、ジルコニア製乳鉢中で３時間混練し、さらにアルミナ製三本ロールにて３回分散を行うことによりオーバーコートガラスペーストを調製した。
Next, the glass powder was mixed and mixed so that the glass powder was 95% by mass and the silica fine powder (manufactured by Nippon Aerosil Co., Ltd., trade name: AEROSIL 380, average particle size 7 nm) was 5% by mass. Subsequently, it mix | blended so that the obtained mixture might be 60 mass% and a resin component (what contains ethyl cellulose and alpha terpineol in the ratio of 85:15 by mass ratio) may be 40 mass%. Then, an overcoat glass paste was prepared by kneading in a zirconia mortar for 3 hours and further dispersing three times with an alumina three-roll.
次に、こうして作製されたオーバーコートガラスペースト層付きの上層用グリーンシートと、導体ペースト層付きの内層用グリーンシートおよび下層用グリーンシート（未焼成本体部材）を所定の順で重ね合わせ、さらに上層用グリーンシートの上に枠体用グリーンシートを重ねた後、熱圧着により一体化した。こうして、未焼成基板が得られた。
Next, the green sheet for the upper layer with the overcoat glass paste layer thus prepared, the green sheet for the inner layer with the conductive paste layer, and the green sheet for the lower layer (unfired main body member) are superposed in a predetermined order, and the upper layer The green sheet for the frame body was overlaid on the green sheet for use, and then integrated by thermocompression bonding. Thus, an unfired substrate was obtained.
得られた未焼成基板を、５５０℃で５時間保持して脱脂し、さらに８７０℃で３０分間保持して焼成して、発光素子搭載用基板１を製造した。得られた発光素子搭載用基板１において、焼成後のオーバーコート層５の厚さを断面観察により測定した。断面観察は、オーバーコート層５を含む断面を鏡面研磨し、電子顕微鏡（日立ハイテクノロジーズＳ３０００）により１５００倍に拡大して測長した。また、実施例１～３および比較例２において、オーバーコート層５の表面粗さＲａをサーフコム１４００Ｄ（東京精密社製）により測定した。測定結果を表１に示す。なお、オーバーコート層５を設けなかった比較例１においては、基板本体２の搭載面の表面粗さＲａを同様にして測定した。そして、測定結果をオーバーコート層５等の表面粗さＲａの欄に示した。
The obtained unfired substrate was degreased by holding at 550 ° C. for 5 hours, and further held and fired at 870 ° C. for 30 minutes to produce a light emitting element mounting substrate 1. In the obtained light emitting element mounting substrate 1, the thickness of the overcoat layer 5 after firing was measured by cross-sectional observation. For cross-sectional observation, the cross-section including the overcoat layer 5 was mirror-polished and measured with an electron microscope (Hitachi High-Technologies S3000) at a magnification of 1500 times. In Examples 1 to 3 and Comparative Example 2, the surface roughness Ra of the overcoat layer 5 was measured with Surfcom 1400D (manufactured by Tokyo Seimitsu Co., Ltd.). The measurement results are shown in Table 1. In Comparative Example 1 in which the overcoat layer 5 was not provided, the surface roughness Ra of the mounting surface of the substrate body 2 was measured in the same manner. The measurement results are shown in the column of the surface roughness Ra of the overcoat layer 5 and the like.
次に、上記で作製した発光素子搭載用基板１の８箇所の搭載部Ｔに、それと同形同サイズの２ワイヤタイプのＬＥＤ素子８個を配置し、搭載した。具体的には、８箇所の搭載部５にそれぞれＬＥＤ素子（エピスター社製、商品名：ＥＳ－ＣＥＢＬＶ２４）をダイボンド材（信越化学工業社製、商品名：ＫＥＲ－３０００－Ｍ２）により固定し、各ＬＥＤ素子が有する一対の電極をボンディングワイヤ１２によってそれぞれ第１の電極４１と第２の電極４２に電気的に接続した。こうして８個のＬＥＤ素子が電気的に並列に接続されるようにした。さらに、封止剤（信越化学工業社製、商品名：ＳＣＲ－１０１６Ａ）を用いて封止層１３を形成した。
Next, eight 2-wire type LED elements of the same shape and size were arranged and mounted on the eight mounting portions T of the light-emitting element mounting substrate 1 produced as described above. Specifically, the LED elements (trade name: ES-CEBLV24, manufactured by Epistar Co., Ltd.) are respectively fixed to the eight mounting portions 5 with a die bond material (trade name: KER-3000-M2 manufactured by Shin-Etsu Chemical Co., Ltd.). A pair of electrodes included in each LED element was electrically connected to the first electrode 41 and the second electrode 42 by the bonding wire 12, respectively. In this way, eight LED elements were electrically connected in parallel. Further, a sealing layer 13 was formed using a sealing agent (trade name: SCR-1016A, manufactured by Shin-Etsu Chemical Co., Ltd.).
こうして得られた発光装置１０について、以下の方法で熱抵抗を測定した。すなわち、実施例１～３、比較例１，２で得られた発光装置１０における発光素子搭載用基板１の熱抵抗を、熱抵抗測定器（嶺光音電機社製、商品名：ＴＨ－２１６７）を用いて測定した。なお、印加電流は９６０ｍＡとし、電圧降下が飽和する時間まで通電し、降下した電圧と発光素子の温度－電圧降下特性から導かれる温度係数によって飽和温度を算出し、熱抵抗を求めた。
The thermal resistance of the light emitting device 10 thus obtained was measured by the following method. That is, the thermal resistance of the light-emitting element mounting substrate 1 in the light-emitting devices 10 obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was measured using a thermal resistance measuring instrument (trade name: TH-2167, manufactured by Gwangon Electric Co., Ltd.). ). The applied current was set to 960 mA, current was applied until the voltage drop was saturated, the saturation temperature was calculated from the dropped voltage and the temperature coefficient derived from the temperature-voltage drop characteristics of the light emitting element, and the thermal resistance was obtained.
熱抵抗の測定結果を表１に示す。なお、熱抵抗は、基板本体の搭載面にオーバーコート層５を形成しない比較例１の発光装置１０における熱抵抗を１００としたときの相対値で示した。数値が小さいほど、熱放散性が良好であることを意味する。
Table 1 shows the measurement results of thermal resistance. The thermal resistance is shown as a relative value when the thermal resistance in the light emitting device 10 of Comparative Example 1 in which the overcoat layer 5 is not formed on the mounting surface of the substrate body is 100. It means that heat dissipation is so favorable that a numerical value is small.
表１から、オーバーコート層５が、基板本体２の搭載面の表面粗さＲａ（比較例１における表面粗さＲａに相当する）０．３１μｍの３～２０倍の厚さを有し、かつオーバーコート層５自体の表面粗さＲａが０．１５μｍ以下となっている実施例１～３の発光装置１０では、オーバーコート層５を持たない比較例１の発光装置１０に比べて、熱抵抗が大幅に低減されており、熱放散性が高くなっていることがわかる。
From Table 1, the overcoat layer 5 has a thickness 3 to 20 times the surface roughness Ra of the mounting surface of the substrate body 2 (corresponding to the surface roughness Ra in Comparative Example 1) 0.31 μm, and In the light emitting devices 10 of Examples 1 to 3 in which the surface roughness Ra of the overcoat layer 5 itself is 0.15 μm or less, the thermal resistance is higher than that of the light emitting device 10 of Comparative Example 1 that does not have the overcoat layer 5. Is significantly reduced, and it can be seen that the heat dissipation is high.
オーバーコート層５の厚さが基板本体２の搭載面の表面粗さＲａの２０倍を超えている比較例２の発光装置１０では、オーバーコート層５の表面粗さＲａは極めて小さく、オーバーコート層５表面の平滑・平坦性は良好であるが、ガラス材料からなる厚いオーバーコート層が熱伝導の障害となるため、熱抵抗が高くなっている。
In the light emitting device 10 of Comparative Example 2 in which the thickness of the overcoat layer 5 exceeds 20 times the surface roughness Ra of the mounting surface of the substrate body 2, the surface roughness Ra of the overcoat layer 5 is extremely small. Although the smoothness and flatness of the surface of the layer 5 is good, a thick overcoat layer made of a glass material becomes an obstacle to heat conduction, so that the thermal resistance is high.
本発明によれば、発光素子搭載用基板の反射性が高いうえに、放熱性に優れているため、この基板を使用して発光装置とした場合に、光取り出し効率が良好であり、高輝度の発光が得られる。そして、このような発光素子搭載用基板を用いた本発明の発光装置は、例えば、携帯電話や大型液晶ディスプレイ等のバックライト、自動車用あるいは装飾用の照明、その他の光源として好適に使用できる。
なお、２０１０年９月１７日に出願された日本特許出願２０１０－２０９６６３号の明細書、特許請求の範囲、図面及び要約書の全内容をここに引用し、本発明の開示として取り入れるものである。 According to the present invention, the light-emitting element mounting substrate has high reflectivity and excellent heat dissipation. Therefore, when this substrate is used as a light-emitting device, the light extraction efficiency is good and the brightness is high. Can be obtained. And the light-emitting device of this invention using such a light emitting element mounting substrate can be used conveniently as backlights, such as a mobile telephone and a large sized liquid crystal display, the illumination for motor vehicles or decoration, and another light source, for example.
It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application 2010-209663 filed on September 17, 2010 are incorporated herein as the disclosure of the present invention. .
なお、２０１０年９月１７日に出願された日本特許出願２０１０－２０９６６３号の明細書、特許請求の範囲、図面及び要約書の全内容をここに引用し、本発明の開示として取り入れるものである。 According to the present invention, the light-emitting element mounting substrate has high reflectivity and excellent heat dissipation. Therefore, when this substrate is used as a light-emitting device, the light extraction efficiency is good and the brightness is high. Can be obtained. And the light-emitting device of this invention using such a light emitting element mounting substrate can be used conveniently as backlights, such as a mobile telephone and a large sized liquid crystal display, the illumination for motor vehicles or decoration, and another light source, for example.
It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application 2010-209663 filed on September 17, 2010 are incorporated herein as the disclosure of the present invention. .
１…発光素子搭載用基板、２…基板本体、３…枠体、４…配線導体層（配線導体ペースト層）、５…オーバーコート層（オーバーコートガラスペースト層）、６…外部電極端子（外部電極端子用導体ペースト層）、７…接続ビア（接続ビア用導体ペースト層）、８…サーマルビア（サーマルビア用導体ペースト層）、９…放熱層（放熱層用導体ペースト層）、１０…発光装置、１１…発光素子、１２…ボンディングワイヤ、１３…封止層、２１…搭載全体領域、４１…第１の電極（第１の電極用導体ペースト層）、４２…第２の電極（第２の電極用導体ペースト層）、４３…連結用導体層（連結用導体電極用導体ペースト層）。
DESCRIPTION OF SYMBOLS 1 ... Light emitting element mounting substrate, 2 ... Substrate body, 3 ... Frame, 4 ... Wiring conductor layer (wiring conductor paste layer), 5 ... Overcoat layer (overcoat glass paste layer), 6 ... External electrode terminal (external) Conductor paste layer for electrode terminals), 7 ... Connection via (conductor paste layer for connection via), 8 ... thermal via (conductor paste layer for thermal via), 9 ... heat dissipation layer (conductor paste layer for heat dissipation layer), 10 ... light emission Device: 11 ... Light emitting element, 12 ... Bonding wire, 13 ... Sealing layer, 21 ... Whole mounting area, 41 ... First electrode (first electrode conductor paste layer), 42 ... Second electrode (second electrode) Electrode conductor paste layer), 43... Connecting conductor layer (connecting conductor electrode conductor paste layer).
Claims (8)
- 無機絶縁材料からなり、発光素子が搭載される搭載部を含む搭載面を有する基板本体と、
前記基板本体の前記搭載面に少なくとも前記搭載部を覆うように形成された、ガラスを主体とする材料からなるオーバーコート層とを有し、
前記オーバーコート層は、前記基板本体の前記搭載面の表面粗さＲａの３～２０倍の厚さを有し、かつ該オーバーコート層の表面粗さＲａは０．１５μｍ以下であることを特徴とする発光素子搭載用基板。 A substrate body made of an inorganic insulating material and having a mounting surface including a mounting portion on which a light emitting element is mounted;
An overcoat layer made of a material mainly composed of glass, formed to cover at least the mounting portion on the mounting surface of the substrate body;
The overcoat layer has a thickness of 3 to 20 times the surface roughness Ra of the mounting surface of the substrate body, and the surface roughness Ra of the overcoat layer is 0.15 μm or less. A light-emitting element mounting substrate. - 前記基板本体は、ガラス粉末とセラミックス粉末とを含むガラスセラミックス組成物の焼結体からなる請求項１に記載の発光素子搭載用基板。 The light emitting element mounting substrate according to claim 1, wherein the substrate body is made of a sintered body of a glass ceramic composition containing glass powder and ceramic powder.
- 前記セラミックス粉末は、アルミナ粉末と、アルミナよりも高い屈折率を有するセラミックスの粉末を含むことを特徴とする請求項２に記載の発光素子搭載用基板。 3. The light-emitting element mounting substrate according to claim 2, wherein the ceramic powder includes an alumina powder and a ceramic powder having a higher refractive index than alumina.
- 前記セラミック粉末は、チタニア粉末、ジルコニア粉末、安定化ジルコニア粉末、酸化亜鉛粉末、チタン酸バリウム粉末、チタン酸鉛粉末からなる群から選ばれる少なくとも１種である請求項２、または３に記載の発光素子搭載用基板。 4. The light emitting device according to claim 2, wherein the ceramic powder is at least one selected from the group consisting of titania powder, zirconia powder, stabilized zirconia powder, zinc oxide powder, barium titanate powder, and lead titanate powder. Device mounting board.
- 前記オーバーコート層を構成する前記ガラスを主体とする材料は、８５０℃以下の軟化点を有する請求項１～４のいずれか１項に記載の発光素子搭載用基板。 The light emitting element mounting substrate according to any one of claims 1 to 4, wherein the glass-based material constituting the overcoat layer has a softening point of 850 ° C or lower.
- 前記オーバーコート層を構成するガラスは、少なくとも、ＳｉＯ２およびＢ２Ｏ３を含有し、かつＮａ２ＯとＫ２Ｏから選ばれる少なくとも１種を含有する請求項１～５のいずれか１項に記載の発光素子搭載用基板。 The glass constituting the overcoat layer contains at least SiO 2 and B 2 O 3 and contains at least one selected from Na 2 O and K 2 O. A substrate for mounting a light-emitting element according to 1.
- 前記ガラスは、酸化物基準のモル％表示で、ＳｉＯ２を６２～８４％、Ｂ２Ｏ３を１０～２５％、Ａｌ２Ｏ３を０～５％、ＭｇＯを０～１０％、Ｎａ２ＯおよびＫ２Ｏから選ばれる少なくとも１種を合計で１～５％含有し、ＳｉＯ２とＡｌ２Ｏ３の含有量の合計が６２～８４％であり、ＣａＯ、ＳｒＯおよびＢａＯから選ばれる少なくとも１種を含有する場合にその含有量の合計が５％以下であるホウケイ酸ガラスである請求項６に記載の発光素子搭載用基板。 The glass is expressed in terms of mol% based on oxide, SiO 2 62-84%, B 2 O 3 10-25%, Al 2 O 3 0-5%, MgO 0-10%, Na 2 The total content of at least one selected from O and K 2 O is 1 to 5%, the total content of SiO 2 and Al 2 O 3 is 62 to 84%, and at least selected from CaO, SrO and BaO The board | substrate for light emitting element mounting of Claim 6 which is the borosilicate glass whose sum total is 5% or less when it contains 1 type.
- 請求項１～７のいずれか１項に記載の発光素子搭載用基板と、
前記発光素子搭載用基板の前記搭載部に搭載された発光素子
を備えたことを特徴とする発光装置。 A light emitting element mounting substrate according to any one of claims 1 to 7,
A light emitting device comprising: a light emitting element mounted on the mounting portion of the light emitting element mounting substrate.
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| JPH01290280A (en) * | 1988-05-18 | 1989-11-22 | Tdk Corp | Glazed ceramic substrate and manufacture thereof |
| JP2002368020A (en) * | 2002-04-30 | 2002-12-20 | Sumitomo Electric Ind Ltd | Submount and semiconductor device |
| JP2006344691A (en) * | 2005-06-07 | 2006-12-21 | Fujikura Ltd | Substrate for mounting light-emitting element and light-emitting element module |
| WO2009128354A1 (en) * | 2008-04-18 | 2009-10-22 | 旭硝子株式会社 | Light-emitting diode package |
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| WO2004084319A1 (en) * | 2003-03-18 | 2004-09-30 | Sumitomo Electric Industries Ltd. | Light emitting element mounting member, and semiconductor device using the same |
| JP5345363B2 (en) * | 2008-06-24 | 2013-11-20 | シャープ株式会社 | Light emitting device |
| KR20130007538A (en) * | 2010-02-25 | 2013-01-18 | 아사히 가라스 가부시키가이샤 | Substrate for mounting light emitting element, and light emitting device |
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| JPH01290280A (en) * | 1988-05-18 | 1989-11-22 | Tdk Corp | Glazed ceramic substrate and manufacture thereof |
| JP2002368020A (en) * | 2002-04-30 | 2002-12-20 | Sumitomo Electric Ind Ltd | Submount and semiconductor device |
| JP2006344691A (en) * | 2005-06-07 | 2006-12-21 | Fujikura Ltd | Substrate for mounting light-emitting element and light-emitting element module |
| WO2009128354A1 (en) * | 2008-04-18 | 2009-10-22 | 旭硝子株式会社 | Light-emitting diode package |
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