JP2008108970A - Wiring substrate for luminous element, and luminous apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring substrate for luminous elements which has an excellent heat radiating property and can be manufactured inexpensively, and to provide a luminous apparatus. <P>SOLUTION: In the wiring substrate for luminous elements, an insulating layer 5 is so provided on the principal surface of a flat-plate-form metal base body 1 made of a sintered metal as to substantially reduce its area requiring an expensive plating without sacrificing its heat radiating property. Further, it reduces its area wherein conductive materials are exposed to the external and suppresses the generation of its electrical short-circuit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting element wiring board and a light emitting device for mounting a light emitting element such as a light emitting diode.

  Conventionally, light emitting devices using LEDs have been used for various applications because of their extremely high luminous efficiency and the small amount of heat generated by light emission compared to incandescent bulbs. However, since it emits less light than incandescent bulbs and fluorescent lamps, it is not used for illumination but as a light source for display, and the energization amount is as small as about 30 mA (for example, see Patent Document 1). reference.).

  In recent years, with the increase in brightness and whiteness of light-emitting devices using light-emitting elements, light-emitting devices have been frequently used for backlights of mobile phones, large liquid crystal TVs, and the like. However, the luminance of the light emitting element is improved and the heat generated from the light emitting device is also increasing. In order to prevent a decrease in luminance of the light emitting element, a wiring board for a light emitting element having a high heat dissipation property that dissipates such heat more quickly than the element is required (for example, Patent Documents 2 and 3). See).

In response to such a requirement, the present applicant has proposed a wiring board for a light emitting element including a flat metal base made of a sintered metal having excellent heat dissipation (see, for example, Patent Document 4).
JP 2002-134790 A Japanese Patent Laid-Open No. 11-112025 JP 2003-347600 A Japanese Patent Application No. 2006-019581

  However, although the method disclosed in Patent Document 4 can improve heat dissipation, most of the wiring board for light emitting element is formed of sintered metal, which increases the plating area and increases the cost. There is a problem that. Accordingly, an object of the present invention is to provide a light-emitting element wiring board and a light-emitting device that are inexpensive and excellent in heat dissipation.

  A wiring board for a light-emitting element according to the present invention includes a flat metal substrate made of sintered metal, a mounting portion for mounting a light-emitting element formed on the upper surface of the metal substrate, and a metal substrate that is thinner than the metal substrate. An insulating layer made of ceramic covering the lower surface, a through insulator made of ceramic that penetrates at least the metal substrate, a through conductor that is electrically insulated from the metal substrate and penetrates the inside of the through insulator, The wiring that is electrically connected to the through conductor and insulated from the metal base and provided around the mounting portion; and the wiring that is electrically connected to the through conductor and insulated from the metal base; An external connection terminal that penetrates, and a reflective portion made of sintered metal formed so as to surround the mounting portion and the wiring, the metal base, the insulating layer, and the through insulator, Serial it through conductor and the wiring and the external connection terminal and said reflection portion is fired simultaneously, characterized in that plating on the metal substrate is applied.

  In the light-emitting element wiring board according to the present invention, it is preferable that a non-metal coating film is formed on the upper surface of the reflecting portion.

  In the light emitting element wiring board according to the present invention, the coating film is made of ceramics, and the metal base, the insulating layer, the through insulator, the through conductor, the wiring, the external connection terminal, and the reflecting portion. And the coating film are preferably fired at the same time.

  The light-emitting device of the present invention is characterized in that a light-emitting element is mounted on the mounting portion of the light-emitting element wiring board described above.

  The wiring board for a light emitting device of the present invention has a higher thermal conductivity than that of a resin mold substrate, a ceramic substrate, or the like by forming the substrate from a sintered metal, and efficiently generates heat from the light emitting device from the entire substrate. It is possible to quickly dissipate out of the system and to prevent the light emitting element from being heated excessively. For this reason, it is possible to prevent a decrease in luminance or to further increase the luminance. In addition, by forming wiring electrically insulated through an insulator on the surface of the metal substrate and further penetrating through the metal substrate, it is possible to increase the number of layers and to cope with complicated wiring designs and the substrate. Miniaturization is possible. In addition, by forming a reflective portion made of metal so as to surround the light emitting element mounting portion and the wiring, heat generated by the light emitting element can be dissipated not only from the metal substrate but also from the reflective portion. The light emitting element can be protected by the reflecting portion, and a phosphor or the like can be easily disposed around the light emitting element. Further, the light emitted from the light emitting element can be reflected by the reflecting portion to increase the light extraction efficiency, and high luminance can be realized. Furthermore, since the metal substrate and the reflecting portion are made of sintered metal, the metal substrate, the insulating layer, the penetrating insulator, the penetrating conductor, the wiring, the external connection terminal, and the reflecting portion can be produced by simultaneous firing. Thus, the cost can be reduced. Furthermore, since the exposed area of the metal substrate can be reduced, the plating area can be reduced, and the cost can be reduced.

  In addition, since the non-metallic coating film is formed on the upper surface of the reflecting portion, the area to be plated can be further reduced, and the cost can be reduced, which is more preferable.

  Moreover, the coating layer is made of ceramics, and these coating layers can be integrally formed by simultaneously firing the metal substrate, the insulating layer, the penetrating insulator, the penetrating conductor, the wiring, the external connection terminal, and the reflecting portion. The process can be reduced.

  The light-emitting device of the present invention in which the light-emitting element is mounted on the wiring board for the light-emitting element of the present invention described above is inexpensive because the plating cost can be reduced, and heat generated from the light-emitting element can be quickly discharged out of the device. Therefore, the light-emitting device can suppress a decrease in luminance due to heat generation.

  A wiring board for a light-emitting element according to the present invention includes, for example, a light-emitting element formed on a flat metal base 1 made of sintered metal and an upper surface 1a of the metal base 1 as shown in FIG. A mounting portion 3 to be mounted; an insulating layer 5 made of ceramics that is thinner than the metal substrate 1 and covers the lower surface of the metal substrate 1; a through insulator 7 made of ceramics that penetrates at least the metal substrate 1; A through conductor 9 that is electrically insulated and penetrates the inside of the through insulator 7; a wiring 11 that is electrically connected to the through conductor 9, insulated from the metal base 1, and provided around the mounting portion 3; The reflection part 13 made of a sintered metal is formed so as to surround the mounting part 3 and the wiring 11. An external connection terminal 17 for connecting the light emitting element wiring substrate 15 to the external wiring substrate is provided on the lower surface of the light emitting element wiring substrate 15.

  Needless to say, the through conductor 7 may also penetrate the through insulator 7 and the insulating layer 5 to serve as the external connection terminal 17.

  In the light emitting element wiring substrate 15 of the present invention, the metal base 1, the insulating layer 5, the through insulator 7, the through conductor 9, the wiring 11, the external connection terminal 17, and the reflecting portion 13 are simultaneously fired. Yes.

  The exposed surface of the metal base 1 is plated with Au, Ag, Ni, Cu or the like (not shown). The plating is also applied to the surfaces of the wiring 11 and the external connection terminal 17. Moreover, it is desirable that the inner wall surface 13a of the reflecting portion 13 is also subjected to metal plating (not shown). Thereby, the light emitted from the light emitting element is well reflected by the metal plating, and the extraction efficiency of the light emitting device can be improved. In the present invention, since the surface to be subjected to metal plating is formed of sintered metal, there is no need to transfer or print a metal layer on the plating formation portion like a resin mold substrate or a ceramic substrate, and the process is simplified. Can be

  The metal plating is preferably Ag plating from the viewpoint of reflectance, and Ni plating is preferable from the viewpoint of low cost.

  According to the light emitting element wiring substrate 15 of the present invention, the sintered metal is used as the material of the metal base 1 and the reflecting portion 13, and the through insulator 7 and the through conductor 9 are provided so as to penetrate the metal base 1. is important. That is, by using a sintered metal as a material for the metal substrate 1 and the reflection portion 13, heat dissipation higher than that of a resin mold substrate or a ceramic substrate is ensured, and heat generated from the light emitting element is transmitted from the entire wiring board 15 for the light emitting element. It can be released efficiently.

  Further, by providing the insulating layer 5 made of ceramics which is thinner than the metal substrate 1 and covers the lower surface of the metal substrate 1, the light emitting element wiring substrate 15 is mounted on another external wiring substrate (not shown). It is possible to prevent the metal base 1 from coming into contact with another external wiring board and short circuiting the electric circuit. Furthermore, when plating the wiring board 15 for light emitting elements, since the area where the insulating layer 5 is exposed on the surface of the metal substrate 1 is reduced, the plating area can be reduced, thereby reducing the cost. You can also. The insulating layer 5 is desirably formed as thin as possible from the viewpoint of heat dissipation, and the influence on heat dissipation can be reduced by setting the thickness of the insulating layer to 300 μm, particularly 100 μm or less, and further 30 μm or less. The insulating layer 5 is desirably made of the same composition as that of the through insulator 7 in consideration of the bonding property with the through insulator 7.

  Further, by providing the through insulator 7 and the through conductor 9 on the metal base 1, it becomes possible to make the wiring board 15 for the light emitting element multilayer, diversify the wiring design, and reduce the size. And by providing the reflecting part 13 which consists of sintered metals in the metal base | substrate 1, while reflecting the light which arises from a light emitting element, while improving the extraction efficiency of light, the heat generated from the light emitting element is dissipated and it is for light emitting elements. The heat dissipation of the wiring board 15 can be improved.

  Further, by forming the metal substrate 1 and the reflection portion 13 from sintered metal, the metal substrate 1, the through insulator 7, the through conductor 9, the wiring 11, and the reflection portion 13 can be produced by simultaneous firing. Therefore, the number of members and the number of processes can be reduced, and the cost can be reduced.

  In addition, by forming the non-metallic coating film 19 on the upper surface 13b of the reflecting portion 13, the area of the plating applied to the light emitting element wiring substrate 15 can be further reduced. The coating layer 19 may be formed of a resin or the like, but is preferably formed of ceramics having excellent thermal conductivity from the viewpoint of heat dissipation, and is formed of the same composition as the through insulator 7 and the insulating layer 5. It is desirable. Further, when the coating film 19 is made of ceramic, the coating film 19 is simultaneously formed with the metal substrate 1, the insulating layer 5, the through insulator 7, the through conductor 9, the wiring 11, the external connection terminal 17, and the reflecting portion 13. By firing, the number of steps can be reduced, and the bonding property between the coating film 19 and the reflecting portion 13 can be easily improved.

  Further, as shown in FIG. 1B, the boundary between the metal substrate 1 and the through insulator 7 on the upper surface of the light emitting element wiring substrate 15 is liable to generate cracks or gaps, and therefore the covering insulating layer It is desirable to cover with 21. The covering insulating layer 21 is formed, for example, in a ring shape so that the through conductor 9 is exposed and connected to the wiring 11. The covering insulating layer 21 is desirably made of the same composition as that of the through insulator 7 in consideration of the bonding property with the through insulator 7.

  Furthermore, it is desirable that the thermal conductivity of the metal substrate 1 is 150 W / (m · K) or more. Thereby, favorable heat dissipation can be realized and heat generated from the light emitting element can be quickly dissipated.

  And it is desirable for the metal base | substrate 1 to have at least 1 sort (s) as a main component among W, Mo, and Cu. Since W and Mo are refractory metals, they can be co-fired with high-temperature fired ceramics at about 1300 to 1600 ° C. Furthermore, since the coefficient of thermal expansion is close to that of ceramics forming the insulating layer, a highly reliable wiring board for a light-emitting element can be manufactured. Cu has a high thermal conductivity and is particularly excellent in heat dissipation. Further, for example, when so-called glass ceramics is used as the through insulator 7 and the Cu content is increased, the light emitting element wiring substrate 15 can be fired at a low temperature of about 1000 ° C.

  Further, by combining these metals, the metal substrate 1 having a desired thermal conductivity and thermal expansion coefficient can be formed.

  Moreover, it is desirable that the reflecting portion 13 is made of the same main component as the metal substrate 1. As a result, it is possible to suppress the occurrence of problems such as the formation of an alloy between the metal base 9 and the metal base 1 and the disturbance of the densification behavior. Moreover, the deformation | transformation by simultaneous baking of the metal base | substrate 1 and the reflection part 13 can be suppressed, and the wiring board 15 for light emitting elements with a high dimensional accuracy can be obtained easily.

  Moreover, it is desirable that the through conductor 9 and the wiring 11 have at least one of W, Mo, Cu, and Ag as a main component. Thereby, since the through conductor 9 and the wiring 11 having low electric resistance can be formed, the light emitting element wiring substrate 15 having excellent electric characteristics can be obtained.

  In addition, it is needless to say that metals such as Al, Ag, Au, and Pt can be used for the metal substrate 1, the through conductor 9, and the wiring 11, although they are somewhat expensive.

  The through insulator 7, the insulating layer 5, the covering layer 19, and the covering insulating layer 21 are mainly composed of at least one of alumina, mullite, zirconia, magnesia, calcia, aluminum nitride, silicon nitride, and glass ceramics. It is desirable to do. By using these materials having excellent insulating properties, the through conductor 9 and the wiring 11 can be sufficiently insulated from the metal substrate 1 even if the through insulator 7 and the covering insulating layer 21 are thin. 7 and the covering insulating layer 21 can be formed with high density, and simultaneous firing with the metal substrate 1 is facilitated.

  In the light emitting element wiring substrate 15 of the present invention, the connection terminal 17 to the external wiring substrate is provided on the lower surface 15b of the light emitting element wiring substrate 15, and the covering insulating layer 21 is provided. Is desirable.

  Needless to say, the metal substrate 1 may be multi-layered, and the inner wall surface 13a of the reflecting portion 13 may be provided with an inclination.

  2A and 2B, the light-emitting element 23 is fixed to the light-emitting element wiring substrate 15 by a connection layer 25, and power is supplied by a bonding wire 27. Needless to say, the connection form with the wiring board 15 may be flip-chip connection.

  Further, the light emitting element 23 is covered with the molding material 29, but may be sealed with a lid (not shown) without using the molding material 29, or the molding material 29 and the lid And may be used in combination. When using a lid, it is desirable to use a translucent material such as glass for the lid.

  In addition, you may make this mold material 29 contain the fluorescent substance (not shown) for wavelength-converting the light which the light emitting element 23 radiates | emits as needed.

  Further, from the viewpoint of efficiently transferring the heat of the light emitting element 23 to the metal substrate 1, it is desirable to use a metal such as solder, indium, AuSn alloy as the connection layer 25.

  According to the light-emitting device 31 of the present invention in which the light-emitting element 23 is mounted on the light-emitting element wiring substrate 15 of the present invention described above, heat generated from the light-emitting element 23 can be quickly discharged outside the apparatus. A reduction in luminance can be suppressed.

  Next, the manufacturing method of the light emitting element wiring board 15 in the present invention will be described.

  First, by firing as described below, a metal sheet to be the metal substrate 1, a ceramic green sheet to be a through insulator, and a conductor paste to be a through metal body are produced. Moreover, a ceramic paste is produced as needed.

  The metal sheet is formed on a sheet by a conventionally known doctor blade method or the like from a metal slurry prepared by mixing a metal powder, a resin, and a solvent at a predetermined ratio. The metal slurry may contain ceramic powder as necessary.

  The ceramic green sheet is also formed into a sheet shape by a doctor blade method or the like from a ceramic slurry formed from ceramic powder, resin, solvent, and the like.

  The ceramic powder used for the metal sheet and the ceramic green sheet, and the particle diameter of the metal powder is preferably about 0.01 to 10 μm as an average particle diameter. Particularly, powder in the range of 1 to 5 μm is handled and sintered. Is excellent.

  Desirably, a conductive paste 45 containing at least one of W, Mo, Cu, and Ag as a main component is prepared. The metal powder, resin and solvent are mixed at a predetermined ratio, and the solvent is removed by heating under reduced pressure or the like. Moreover, you may make a conductor paste contain a ceramic powder as needed.

  The ceramic paste is prepared by mixing ceramic powder, resin and solvent and removing the solvent.

  The metal powder used for the conductor paste and the ceramic paste, and the ceramic powder having an average particle diameter of about 0.01 to 10 μm is preferably used. Particularly, powder in the range of 1 to 5 μm is used for handling and sintering. Are better.

  First, as shown in FIG. 3A, a via hole 47 having a diameter of 50 to 250 μm is formed in the ceramic green sheet 43 by, for example, a micro drill or a laser, and a conductor is formed in the via hole 47 as shown in FIG. The paste 45 is embedded by printing or the like to form a through conductor molded body 45a, and a conductor embedded sheet 49 is produced.

  Further, as shown in FIG. 3C, a metal sheet 54 is disposed on the upper surface of the mold 53 having the punched holes 51, and as shown in FIG. Punch out.

  Further, on the metal sheet 54 punched out as shown in FIG. 4 (e), a conductor embedded sheet 49 in which the conductor paste 45 is embedded in the ceramic green sheet 43 in advance is arranged, as shown in FIG. 4 (f). The conductor embedding sheet 49 is punched out with the pressing die 55 and at the same time, a part of the conductor embedding sheet 49 is inserted into the hole formed in the metal sheet 54. Then, by removing unnecessary portions of the metal sheet 54 and the conductor-embedded sheet 49, the composite molded body 57 to be the through conductor 9, the through insulator 7, and the metal substrate 1 after firing as shown in FIG. Can be produced. It is desirable that the metal sheet 54 and the ceramic green sheet 43 have substantially the same thickness.

  Then, for example, as shown in FIG. 4 (h), a conductor paste is printed so as not to contact the metal sheet 54 on the surface of the composite molded body 57 and to cover one end face of the through conductor molded body 45a. By forming the wiring formed body etc., the wiring molded body 59 to be the wiring 11 after firing can be formed. A ceramic green sheet 43 that has been drilled in advance is laminated on the end surface of the through conductor molded body 45a that is not formed with the conductor paste, and the conductor paste is formed by printing or the like. A wiring molded body 59 to be the connection terminal 17 can be manufactured.

  Needless to say, the wiring molded body 59 formed of the conductive paste can be used as an internal wiring after firing, for example.

  The wiring molded body 59 is formed so as to cover the boundary between the ceramic green sheet 43 and the through conductor molded body 45a in order to suppress the occurrence of cracks and gaps at the boundary between the through insulator 7 and the through conductor 9. It is desirable.

  For example, before forming the wiring molded body 59, a ceramic paste is applied to the surface of the composite molded body 57 produced in FIG. 4 (g) as shown in FIG. It is desirable to form the covering insulating layer formed body 61 so as to expose the through conductor formed body 45 a and to cover the boundary between the metal sheet 54 and the ceramic green sheet 43. Thereby, it can suppress that a crack and a clearance gap generate | occur | produce in the boundary of the metal base | substrate 1 and the penetration insulator 7. FIG. In order to expose the through conductor molded body 45a, the covering insulating layer molded body 61 may be formed in a ring shape or a donut shape.

  In addition, the insulating layer molded body 62 to be the insulating layer 5 formed on the lower surface of the metal substrate 1 may be formed using, for example, a ceramic slurry, as in the case of the coated insulating layer molded body 61, and prepared in advance. It may be formed using a ceramic green sheet provided with a through hole. Needless to say, the insulating layer 5 needs to be formed so as to cover the lower surface of the metal substrate 1, unlike the covering insulating layer 21.

  That is, it is important that the insulating layer 5 is formed over the entire lower surface of the metal substrate 1. Therefore, as shown in FIG. 5B, the insulating layer formed body 62 needs to be formed so as to cover the entire surface of the metal sheet 54.

  Then, the connection terminal molded body 58 and the insulating layer molded body are formed by forming the connection terminal molded body 58 that becomes the connection terminal after firing so as to be connected to the through conductor molded body 45a and not to be connected to the metal sheet 54. The composite molded body 57 including 62 can be manufactured.

  Further, as shown in FIG. 5C, the insulation layer molded body 61 and the wiring molded body 59 are formed by connecting the through conductor molded body 45 a and forming the wiring molded body 59 so as not to be connected to the metal sheet 54. Can be produced.

  For example, when a plurality of composite molded bodies 57 including the wiring molded body 59 and the covering insulating layer molded body 61 are laminated, the wiring molded body 59 may become an inner layer wiring after firing, and the covering insulating layer forming The body 61 may become an internal insulating layer after firing.

  Below, the formation method of the reflection part 13 is demonstrated. First, as shown in FIG. 6 (a), a metal sheet 54 and a ceramic green sheet 43 are laminated, and through holes 71 are formed in the laminate as shown in FIG. 6 (b). The reflection part molded body 73 to be 13 was formed.

  Furthermore, for example, by laminating a metal sheet 54 provided with an insulating layer formed body 62 as shown in FIG. 5B, the light emitting element wiring substrate 15 of the present invention is obtained after firing as shown in FIG. 6C. A molded body can be easily produced.

  3 to 5 are enlarged views of the main part of the portion where the through conductor 9 is formed, and a plurality of through conductor molded bodies 45a shown in FIGS. 3 to 5 may be formed on the metal sheet 54. Needless to say, it is good.

  In addition, the inner wall surface 13a of the reflection part 13 may be arrange | positioned perpendicularly | vertically with respect to the metal base | substrate 1 as shown to Fig.1 (a), and may be arrange | positioned so that it may incline. The reflecting part 13 whose inner wall surface 13a is vertical may be produced by punching with a normal mold, and the reflecting part 13 whose inner wall surface 13a is inclined has a die inner diameter of 0. 0 than the outer diameter of the punch, for example. The metal sheet 54 can be manufactured by punching using a punching die having a size of about 05 to 1 mm.

  The shape of the through insulator 7 and the through conductor 9 may be a square shape or a prism shape, or may be a desired shape such as a circular shape or a cylindrical shape.

  Needless to say, the wiring molded body 59 can be formed by a thin film method or by transferring a metal foil onto the surface of the molded body.

  W powder with a purity of 99% or more and an average particle size of 2.0 μm is mixed in a proportion of 70% by mass, Cu powder with a purity of 99% or more and an average particle size of 2.0 μm is mixed in a proportion of 30% by mass, and a molding organic resin (binder ) And an acrylic binder and toluene were added as solvents to prepare a slurry to be a metal sheet. Thereafter, a metal sheet was produced by a doctor blade method.

  Also, after mixing W powder with a purity of 99% or more and an average particle diameter of 2 μm with 70% by mass, purity 99% or more of Cu powder with an average particle diameter of 2 μm and acrylic binder and acetone as a solvent, Acetone was removed to prepare a conductor paste.

Moreover, 90 mass% of Al ₂ O ₃ powder having a purity of 99% or more and an average particle diameter of 1.5 μm as raw material powder, and 5 mass% of Mn ₂ O ₃ powder having a purity of 99% or more and an average particle diameter of 1.3 μm. Then, an SiO ₂ powder having a purity of 99% or more and an average particle size of 1.0 μm was mixed at a ratio of 5 mass%, and in the same manner as the metal sheet, an acrylic binder and toluene were mixed to prepare a ceramic slurry. Thereafter, a ceramic green sheet having Al ₂ O ₃ as a main component and substantially the same thickness as the metal sheet was produced by a doctor blade method.

Also, Al ₂ O ₃ powder, Mn ₂ O ₃ powder and SiO ₂ powder are mixed at the same ratio as the ceramic green sheet, and an acrylic binder and acetone are added thereto, and then the solvent is removed by heating under reduced pressure. A ceramic paste was prepared.

  Next, the ceramic green sheet was punched to form a via hole having a diameter of 200 μm, and a conductor paste was filled in the via hole by a screen printing method to produce a conductor embedded sheet.

  Then, a through hole is formed at a predetermined position of the metal sheet, and a part of the conductor embedded sheet is fitted into the through hole by pressing a through hole forming portion of the metal sheet from the conductor embedded sheet. And integrated.

  Three molded bodies in which such a metal sheet and a conductor-embedded sheet were integrated were stacked and laminated.

  Then, a coated insulating layer molded body was formed in a ring shape on one main surface of the laminate by using screen printing using a ceramic paste so as to cover the boundary between the metal sheet and the ceramic green sheet. At this time, the conductive paste serving as the through conductor filled in the via hole was exposed. Furthermore, a conductor paste was printed and applied on the covering insulating layer molded body so as to cover the through conductor molded body, and a wiring molded body was formed so as to become wiring and connection terminals after firing.

  Moreover, the ceramic paste was apply | coated to the main surface opposite to the main surface in which the coating insulating layer molded object was formed, and the insulating layer molded object was formed. In addition, this insulating layer molded body became an insulating layer after firing, and the thickness after firing was set to the values shown in Table 1.

  The insulating layer molded body was formed so as to expose a part of the ceramic green sheet and the through conductor molded body and to form a ring-shaped hole so as to cover the boundary between the ceramic green sheet and the metal sheet. And the external connection terminal molded object used as an external connection terminal after baking was formed by carrying out printing application | coating of the conductor paste in this ring-shaped hole.

  In this way, a composite molded body was prepared in which a metal sheet was provided with a through insulator molded body, a through conductor molded body, an insulating layer molded body, a coated insulating layer molded body, a wiring molded body, and an external connection terminal molded body.

  Furthermore, a ceramic green sheet is arranged on the surface, a two-layer metal sheet and a single-layer ceramic green sheet are laminated, a hole is formed in this laminate, and a reflecting portion molded body that becomes a reflecting portion after firing is produced. did.

  Moreover, the metal sheet of 3 layers was laminated | stacked, the hole was formed in this laminated body, and the reflection part molded object used as a reflection part after baking was produced.

  The metal sheet side of these two types of reflecting portion laminates was brought into contact with the main surface on the side where the wiring molded body of the composite molded body produced previously was formed, and laminated.

  Then, after degreasing in a nitrogen-hydrogen mixed atmosphere at a dew point of + 25 ° C., it was subsequently baked at a maximum temperature of 1300 ° C. for 2 hours in a nitrogen-hydrogen mixed atmosphere at a dew point of + 25 ° C.

  Thus, a wiring board for a light emitting element as shown in FIG. 1 was produced.

  The dimensions of the produced light-emitting element wiring board are 5 mm × 5 mm × 1 mm in outer dimensions, and the thickness of the reflecting portion is 0.4 mm. Further, a bottomed hole having an inner diameter of 3.0 mm was formed in the reflecting portion. Further, the external connection terminal had a size of 1.5 × 1.5 mm after firing.

  Further, as a comparative example, a sample whose base was made of ceramics was produced as follows. The ceramic green sheet was punched to form a via hole having a diameter of 200 μm. The via hole was filled with a conductive paste by a screen printing method and printed and applied in a wiring pattern. Next, a ceramic sheet coated with a conductive paste to be a metal layer was combined, aligned, laminated and pressure-bonded, and a laminate having an outer shape of 5 mm × 5 mm × thickness 0.6 mm after firing was produced. Further, the external connection terminal had a size of 1.5 × 1.5 mm after firing.

  Then, a molded body that becomes a reflective part in which a hole having an inner diameter of 3.0 mm is formed after firing is laminated on the previously produced laminated body after firing, in a nitrogen-hydrogen mixed atmosphere of dew point + 25 ° C. After degreasing, it was subsequently fired for 2 hours at a maximum temperature of 1300 ° C. in a nitrogen-hydrogen mixed atmosphere with a dew point of + 25 ° C.

  The samples of Examples and Comparative Examples were sequentially subjected to Ni, Au, and Ag plating after firing.

  A 1 mm square LED element, which is a light emitting element having an output of 1.5 W, is mounted on the mounting portion using Au-Sn having a thickness of 10 μm as an adhesive on the wiring board for the light emitting element, and the LED element and the connection terminal are connected by a bonding wire. And the LED element and the connection terminal were covered with a molding material made of epoxy resin to obtain a light emitting device.

  A current of 0.4 A was applied to the obtained light emitting device, and total radiant flux measurement was performed.

  Further, the thermal conductivity of the metal substrate and the insulating substrate was measured by a laser flash method using samples formed individually.

Table 1 shows the characteristics and test results of the wiring board for a light-emitting element manufactured through the above steps.

  As shown in Table 1, the wiring board for a light emitting element of the present invention has a sample No. in which an insulating layer outside the scope of the present invention is not provided. Although the total radiant flux is slightly smaller than that of Sample 2, sample No. 2 mainly composed of alumina, which is outside the scope of the present invention. It can be seen that the total radiant flux is sufficiently high compared to 1. In addition, the wiring board for a light emitting element of the present invention has a sample No. in which no insulating layer is provided. Compared to 2, the area where the plating was formed was reduced to about half, and the amount of noble metal used in the plating process could be saved. Further, the area occupied by the conductor on the lower surface of the light emitting element wiring board is the sample No. This is about 1/5 of 2, and the possibility of an electrical short circuit with the wiring formed on the external connection substrate is reduced.

It is sectional drawing of the wiring board for light emitting elements of this invention. It is sectional drawing of the light-emitting device of this invention. It is a principal part expanded sectional view for demonstrating the manufacturing method of the wiring board for light emitting elements of this invention. It is a principal part expanded sectional view for demonstrating the manufacturing method of the wiring board for light emitting elements of this invention. It is a principal part expanded sectional view for demonstrating the manufacturing method of the wiring board for light emitting elements of this invention. It is a principal part expanded sectional view for demonstrating the manufacturing method of the wiring board for light emitting elements of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal base | substrate 1a ... Upper surface 1b of metal base | substrate ... Main surface 3 of the reverse side of a light emitting element wiring board ... Mounting part 5 ... Insulating layer 7 ... Through insulator 9 ... Through conductor 11... Wiring 13... Reflecting portion 13 a... Inner wall surface 13 b of reflecting portion. Non-metallic coating film 21 ... covering insulating layer 23 ... light emitting element 31 ... light emitting device

Claims (4)

A flat metal substrate made of sintered metal, a mounting portion for mounting a light emitting element formed on the upper surface of the metal substrate, an insulating layer made of ceramics that is thinner than the metal substrate and covers the lower surface of the metal substrate; A through insulator made of ceramic that penetrates at least the metal substrate; a through conductor that is electrically insulated from the metal substrate and penetrates the inside of the through insulator; and is electrically connected to the through conductor. In addition, a wiring that is insulated from the metal base and provided around the mounting portion, an external connection terminal that is electrically connected to the through conductor and is insulated from the metal base and penetrates the insulating layer, and the mounting portion And a reflecting portion made of sintered metal so as to surround the wiring, the metal base, the insulating layer, the through insulator, the through conductor, the wiring, and the outer Connecting terminal and the reflective portion is being fired simultaneously, the wiring substrate for light-emitting element, characterized in that plating on the metal substrate is applied. The light-emitting element wiring board according to claim 1, wherein a non-metallic coating film is formed on an upper surface of the reflecting portion. The coating film is made of ceramic, and the metal base, the insulating layer, the through insulator, the through conductor, the wiring, the external connection terminal, the reflection portion, and the coating film are fired simultaneously. The light-emitting element wiring board according to claim 2. A light emitting device comprising a light emitting element mounted on the mounting portion of the light emitting element wiring board according to claim 1.

Images