JP2012018948A - Board for device, light-emitting device and method of manufacturing board for device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a board for devices, a light-emitting device and a method of manufacturing the board for devices, which can prevent the increase in the heat conduction resistance of each thermal via hole formed in the board even if through-holes of respective layers of green sheets are displaced in stacking the green sheets to form a laminate.SOLUTION: A board 1 for devices has: a board main body 2 including a sintered compact of glass ceramic composition containing glass powder and a ceramic filler, and having a device-mount face 21 to mount a light-emitting element 11 thereon; and thermal via holes 6 each provided in the board main body 2 to pierce the main body from the device-mount face 21 to the non-mount face 23 and formed by stacking the plurality of layers from the device-mount face 21 towards the non-mount face 23. In at least two adjacent layers of the stacked layers, the diameter of the thermal via hole 6 in the layer on the side of the device-mount face 21 is smaller than the diameter in the layer in contact with the side of the non-mount face 23.

Description

  The present invention relates to an element substrate on which an element is mounted, a light emitting device including a light emitting element mounted on the element substrate and the element substrate, and a method for manufacturing the element substrate.

  In recent years, with the increase in brightness and whiteness of light emitting diode (LED) elements (chips), white light is emitted using light emitting elements such as LED elements as backlights for lighting, various displays, and large liquid crystal TVs. A light emitting device is used.

  Such a light-emitting device cannot be used outdoors for a long time unless it has excellent weather resistance. Further, if the light extraction efficiency of the light emitting device is low, sufficient light emission luminance cannot be obtained for the same driving power. In addition, if the light emitting device is not excellent in heat dissipation, the amount of heat generated increases as the brightness of the LED element increases, and the temperature rises excessively, so that sufficient light emission luminance cannot be obtained. Therefore, the element substrate for mounting a light emitting element such as an LED element needs to satisfy the required specifications for the respective characteristics of weather resistance, light extraction efficiency, and heat dissipation. Therefore, a low-temperature co-fired ceramic substrate (hereinafter referred to as “LTCC substrate”) is widely used as a device substrate.

  The LTCC substrate includes, for example, a ceramic layer, a front conductor layer and a rear conductor layer formed on the front and rear surfaces of the ceramic layer, and a through conductor that penetrates the ceramic layer and connects the front conductor layer and the rear conductor layer. (For example, refer to Patent Document 1).

  Such an LTCC substrate is provided with a thermal via made of a high thermal conductive material such as a metal so as to penetrate from the mounting surface on which the light emitting element is mounted to the opposite surface thereof, and is transmitted between the mounting surface and the opposite surface. Thermal resistance is reduced. The thermal via forms a through-hole penetrating the green sheet in the green sheet for forming the ceramic layer, and the formed through-hole includes a high thermal conductive material such as metal (usually also a conductive material). It is formed by filling a conductive paste and baking it. For example, an example of an LTCC substrate in which a plurality of thermal vias smaller than a light emitting element are arranged, or an example of an LTCC substrate in which only one having a size approximately the same as the light emitting element is arranged is disclosed (for example, Patent Document 2). reference).

JP 2009-117564 A Japanese Patent Laid-Open No. 2006-41230

  However, an element substrate on which a light emitting element such as the above-described LTCC substrate is mounted has the following problems.

  In the element substrate as described in Patent Document 2, a slurry is prepared by adding a binder to a glass ceramic composition containing glass powder and a ceramic filler, and this is formed into a sheet by a doctor blade method or the like. And drying to produce a green sheet. And the board | substrate for elements is obtained by baking the laminated body formed by laminating | stacking several produced green sheets. A through hole is formed by punching, for example, so as to penetrate the green sheet at the same position of each green sheet, and since the formed through hole is filled with a conductive paste containing a conductive material such as metal, By laminating and firing the green sheets, thermal vias are provided so as to penetrate the element substrate.

  However, when the green sheets are stacked, the position of the green sheet is shifted due to the limit of alignment accuracy, or when the through hole is formed in the green sheet, The position may shift. When such positional deviation of the through holes in each layer occurs, the contact area between the thermal vias in each layer decreases. When the contact area decreases, the heat transfer resistance of the thermal via increases, and the heat dissipation characteristics from the mounting surface of the light emitting element toward the opposite surface deteriorate.

  In addition, the above-described problem is not only in the case where a light emitting element is mounted on an element substrate, but also in recent years, various types of semiconductors such as power-based semiconductor elements, in which the amount of heat generation has increased as the driving frequency of the element has increased. This is also common when mounting elements.

  The present invention has been made in view of the above points, and when a green sheet is laminated to form a laminate, the heat transfer of the formed thermal via is also performed when the position of the through hole of each layer is displaced. Provided are a device substrate, a light emitting device, and a method for manufacturing the device substrate, which can prevent an increase in resistance.

  In order to solve the above problems, the present invention is characterized by the following measures.

  The present invention consists of a sintered body of a glass ceramic composition containing glass powder and a ceramic filler, and has a substrate body having a mounting surface on which a semiconductor element is mounted, and a non-surface opposite from the mounting surface to the mounting surface. A thermal via that is provided in the substrate body so as to penetrate the mounting surface, and in which a plurality of layers are laminated from the mounting surface toward the non-mounting surface; Provided is an element substrate characterized in that the diameter of the thermal via on the mounting surface side is smaller than the diameter of the thermal via on the non-mounting surface side in at least any two layers that are in contact with each other.

  The layer having a thermal via having a small diameter is preferably the outermost layer on the mounting surface side. Moreover, it is preferable that the diameter of the thermal via in each layer gradually increases from the outermost layer on the mounting surface side toward the non-mounting surface within a predetermined distance from the mounting surface. In the thermal via, it is preferable that the diameter of the thermal via in each layer sequentially increases from the outermost layer on the mounting surface side to the outermost layer on the non-mounting surface side.

  The difference in diameter of the thermal vias in the two layers in contact with each other is preferably 30 μm or more and 60 μm or less. Further, the diameter of the thermal via in the layer having the thermal via having a small diameter is 100 μm or more and 200 μm or less, and the height difference between the highest part and the lowest part of the mounting surface in the vicinity of the thermal via is 5 μm or less. It is preferable. Moreover, it is preferable that the thermal via contains silver, and the larger the diameter of the thermal via, the larger the silver content in the thermal via in the layer. The semiconductor element is preferably a light emitting element.

  Moreover, this invention provides the light-emitting device which has the board | substrate for elements based on this invention, and the said light emitting element mounted in the said mounting surface.

  The present invention also includes a substrate body having a mounting surface on which a semiconductor element is mounted, and a surface opposite to the mounting surface from the mounting surface, which is made of a sintered body of a glass ceramic composition including glass powder and a ceramic filler. A thermal via provided in the substrate body so as to penetrate a certain non-mounting surface, and a plurality of layers stacked from the mounting surface toward the non-mounting surface, and the thermal via is a layer to be stacked A method of manufacturing a device substrate, wherein the diameter of the thermal via on the mounting surface side is smaller than the diameter of the thermal via on the non-mounting surface side in at least any two layers in contact with each other. A firing step of firing a laminate formed by laminating a plurality of green sheets made of the glass ceramic composition, each having a through-hole filled with a conductive paste containing The laminated body has at least two arbitrary layers in contact with each other, and the diameter of the through hole in the green sheet on the mounting surface side is smaller than the diameter of the through hole in the green sheet on the non-mounting surface side, A method for manufacturing a device substrate is provided.

  According to the present invention, when forming a laminated body by laminating green sheets, it is possible to prevent an increase in the heat transfer resistance of the formed thermal via even when the position of the through hole of each layer is displaced.

It is sectional drawing which shows an example of the board | substrate for elements concerning embodiment (1st aspect). It is sectional drawing which expands and shows the vicinity of the thermal via in the board | substrate for elements concerning embodiment (1st aspect). It is sectional drawing which expands and shows the vicinity of the thermal via at the time of position shift about the board | substrate for elements concerning a comparative example when laminating | stacking a green sheet. It is sectional drawing which expands and shows the vicinity of the thermal via at the time of position shift, when laminating | stacking a green sheet about the element | substrate board | substrate which concerns on embodiment (1st aspect). It is sectional drawing for demonstrating the height difference between the highest part and the lowest part in a mounting surface. It is sectional drawing which shows another example of the board | substrate for elements provided with the glass film. It is sectional drawing which shows an example of the light-emitting device 10 which concerns on embodiment (1st aspect). It is a figure which shows typically a part of process in the manufacturing method of the board | substrate for elements concerning embodiment (1st aspect). It is sectional drawing which expands and shows the vicinity of the thermal via in the element | substrate board | substrate which concerns on a 2nd aspect. It is sectional drawing which expands and shows the vicinity of the thermal via in the element | substrate board | substrate which concerns on a 3rd aspect.

Next, a mode for carrying out the present invention will be described with reference to the drawings.
(Embodiment)
First, an element substrate and a light emitting device according to an embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing an example of an element substrate 1 according to the present embodiment. FIG. 2 is an enlarged cross-sectional view showing the vicinity of the thermal via 6 in the element substrate 1 according to the present embodiment (first aspect, which will be described later). FIG. 3 is an enlarged cross-sectional view of the vicinity of the thermal via when the element substrate according to the comparative example is displaced when the green sheets are stacked. FIG. 4 is an enlarged cross-sectional view showing the vicinity of the thermal via when the element substrate 1 according to the present embodiment (first aspect) is displaced when the green sheets are stacked. FIG. 5 is a cross-sectional view for explaining the height difference between the highest portion and the lowest portion on the mounting surface 21.

  The element substrate 1 includes a substrate body 2, connection terminals 3, external electrode terminals 4, through conductors 5, and thermal vias 6.

  The substrate body 2 is made of a sintered body of a glass ceramic composition containing glass powder and a ceramic filler, and has a mounting surface 21 on which a light emitting element is mounted as one main surface (upper side in the figure). . A substantially central portion of the mounting surface 21 is a mounting portion 22 on which a light emitting element is actually mounted. The substrate body 2 has a non-mounting surface 23 on which the light emitting element is not mounted as the other main surface. The non-mounting surface 23 is the opposite surface of the mounting surface 21 that is the main surface. 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 and thereafter used.

  The mounting surface 21 is provided with a connection terminal 3 that is electrically connected to the light emitting element. The non-mounting surface 23 is provided with external electrode terminals 4 that are electrically connected to an external circuit. A through conductor 5 that electrically connects the connection terminal 3 and the external electrode terminal 4 is provided inside the substrate body 2.

  The thermal via 6 for reducing the heat transfer resistance is provided in the substrate body 2 so as to penetrate from the mounting surface 21 to the non-mounting surface 23, and a plurality of layers are formed from the mounting surface 21 toward the non-mounting surface 23. It is laminated.

  Here, as shown in FIG. 2, an example in which six layers 2-1 to 2-6 are stacked in the substrate body 2 will be described. The mounting surface side outermost layer 2-1 is the first layer 2-1, the non-mounting surface side outermost layer 2-6 is the sixth layer 2-6, the mounting surface side outermost layer 2-1 and the non-mounting surface side The layers between the outermost layer 2-6 and the second layer 2-2, the third layer 2-3, the fourth layer 2-4, and the fifth layer in order from the mounting surface side outermost layer 2-1 side. Layer 2-5. In addition, the diameters of the thermal vias 61 to 66 in the layers from the first layer 2-1 to the sixth layer 2-6 are D1, D2, D3, D4, D5, and D6.

  Note that the number of layers stacked in the substrate body 2 is not limited to six, and may be any of a plurality of two or more (also in the first to third aspects described later). The same).

  The thermal vias 61 to 66 in each layer may be provided with lands 7 having diameters slightly larger than the diameters D1 to D6 of the thermal vias 61 to 66 on the upper and lower surfaces of the layers. The land 7 is provided to increase the contact area of the thermal vias 61 to 66 in each layer.

  Further, as shown in FIG. 1, a plurality of thermal vias 6 may be provided immediately below the mounting portion 22.

  The thermal via in the present invention is characterized in that the diameter of the thermal via on the mounting surface side is smaller than the diameter of the thermal via on the non-mounting surface side in at least any two layers in contact with each other among the layers to be laminated. There are mainly three modes. In addition to the three modes, each mode may be changed slightly.

  First, a 1st aspect is a case where it has the said relationship in all the layers laminated | stacked (when the number of laminated | stacked layers is 6, all 6 layers). The second aspect has the above relationship from the light emitting element mounting surface to an intermediate layer (for example, when the number of stacked layers is 6, the first layer to the third layer), and the layer having the above relationship This is a case where the diameter of the thermal via is the same in the layer on the most non-mounting surface side and the remaining layers (for example, the third layer and the fourth to sixth layers).

A 3rd aspect is a case where it has the said relationship in the at least 2 layer which mutually contact | connects the middle among the layers to laminate | stack. As an example of the third mode, for example, when the number of stacked layers is 6, the diameters of the thermal vias of the first layer and the second layer are the same, and the thermals of the third layer and the fourth layer are the same. This is a case where the diameter of the via has the above relationship and the diameters of the thermal vias of the fourth layer and the fifth and sixth layers are the same. Hereinafter, the first aspect will be described in order.
[First aspect]
In the element substrate 1 according to the present embodiment, as illustrated in FIG. 2, the thermal vias 6 have the diameters D1 to D6 of the thermal vias 61 to 66 in the respective layers from the mounting surface side outermost layer 2-1 to the non-mounting surface. It gradually increases to the side outermost layer 2-6.

  In the conventional element substrate 101, for example, as shown in FIG. 3, when six layers 102-1 to 102-6 are laminated in the substrate body 102, the diameters of the thermal vias 161 to 166 in each layer are the mounting surface. It is the same from the side outermost layer 102-1 to the non-mounting surface side outermost layer 102-6. Therefore, when forming the laminated body by laminating the green sheets, if the positions of the through holes of each layer are displaced, the contact area between the thermal vias 161 to 166 in each layer may decrease, or each layer May break between the thermal vias 106. As a result, the heat transfer resistance of the formed thermal via 106 increases.

  On the other hand, in the element substrate 1 according to the present embodiment, the diameter of the thermal vias 61 to 66 in each layer sequentially increases from the mounting surface side outermost layer 2-1 to the non-mounting surface side outermost layer 2-6. Therefore, as shown in FIG. 4, when the green sheets are laminated to form a laminate, the contact area between the thermal vias 61 to 66 in each layer is reduced even when the position of the through hole in each layer is displaced. Or disconnection between the thermal vias 61 to 66 in each layer can be prevented. And the increase in the heat transfer resistance of the formed thermal via 6 can be prevented.

  Moreover, when the diameter D1 of the thermal via 61 in the mounting surface side outermost layer 2-1 is less than 100 μm, the heat transfer resistance may increase, and the heat dissipation may be deteriorated. Further, when the diameter D1 of the thermal via 61 in the mounting surface side outermost layer 2-1 exceeds 200 μm, the diameter D6 of the thermal via 66 in the non-mounting surface side outermost layer 2-6 becomes too large. As will be described later, the surface flatness of the conductor paste to be filled may decrease, or the surface flatness of the thermal via 6 to be formed may decrease. Accordingly, the diameter D1 of the thermal via 61 in the mounting surface side outermost layer 2-1 is preferably 100 μm or more and 200 μm or less. Thereby, heat dissipation is securable without reducing the surface flatness of the conductor paste.

  In addition, when the difference in the diameter of the thermal via 6 in the two layers that are in contact with each other is less than 30 μm, the thermal via 6 is likely to be disconnected due to misalignment when the green sheets are stacked. This is because the limit of alignment accuracy when laminating a general green sheet and the limit of punching processing accuracy when forming a through hole in the green sheet are about 20 μm.

  On the other hand, if the difference between the diameters of the thermal vias 6 in the two layers in contact with each other exceeds 60 μm, the diameter of the thermal via 6 in the non-mounting surface side outermost layer 2-6 becomes too large, and the degree of freedom of arrangement of the thermal vias 6 is increased. Limited. Therefore, the difference in the diameter of the thermal via 6 in the two layers in contact with each other is preferably 30 μm or more and 60 μm or less. In the example shown in FIG. 2, all of D2-D1, D3-D2, D4-D3, D5-D4, and D6-D5 are preferably 30 μm or more and 60 μm or less. Thereby, disconnection of the thermal via 6 due to misalignment can be prevented when the green sheets are stacked while securing the degree of freedom of arrangement of the thermal via 6.

  In addition, when the thickness T of the green sheet in each layer is less than 70 μm, the green sheet may be cut or stretched when the green sheet is handled at the time of manufacture. Disconnection of the via 6 is likely to occur. On the other hand, when the thickness T of each layer exceeds 200 μm, the ratio of the height to the diameter of the through hole for forming the thermal via formed in the green sheet (aspect ratio) becomes large, and the conductor paste is filled in the through hole. In addition, there is a possibility that the conductor paste cannot be sufficiently filled.

  Specifically, when the diameter D1 of the thermal via 61 in the mounting surface side outermost layer 2-1 is 100 μm and the thickness T of each layer exceeds 200 μm, the aspect ratio of the through hole for forming the thermal via is 2 Since it becomes larger, the through-hole cannot be sufficiently filled with the conductive paste. Accordingly, the thickness T of the green sheet in each layer is preferably 70 μm or more and 200 μm or less. As a result, when the green sheet is handled, the green sheet can be prevented from being cut or stretched, and the through-hole can be sufficiently filled with the conductive paste.

  That is, the thickness T of each layer of the plurality of layers is preferably 70 μm or more and 200 μm or less.

  Moreover, when the diameter D1 of the thermal via 61 in the mounting surface side outermost layer 2-1 is less than 100 μm, there is a possibility that the conductor paste cannot be sufficiently filled when filling the through hole with the conductor paste. That is, as shown in FIG. 5A, when the thermal via 6 is formed, the height difference ΔH between the highest part and the lowest part on the mounting surface 21 at the periphery of the through hole may exceed 5 μm. On the other hand, when the diameter D1 of the thermal via 61 in the mounting surface side outermost layer 2-1 exceeds 200 μm, the surface flatness of the filled conductive paste may be lowered when the through hole is filled with the conductive paste.

  Moreover, when baking the green sheet with which the through-hole is filled with the conductor paste, a conductor paste may flow and the surface flatness of the thermal via 6 formed may fall. That is, as shown in FIG. 5B, when forming the thermal via 6, the height difference ΔH between the highest part and the lowest part of the mounting surface 21 at the periphery of the through hole may exceed 5 μm. . Accordingly, the diameter D1 of the thermal via 61 in the mounting surface side outermost layer 2-1 is preferably 100 μm or more and 200 μm or less. Thereby, the height difference ΔH between the highest part and the lowest part of the mounting surface 21 in the vicinity of the thermal via 6 can be reduced to 5 μm or less.

  Here, the highest part is the highest part of the mounting surface 21, and usually the vicinity where the thermal via 6 is provided is the highest part. On the other hand, the lowest part is the lowest part of the mounting surface 21, and usually the middle part between adjacent thermal vias 6 is the lowest part. The height difference ΔH is obtained as a difference in height between the highest part and the lowest part. The height difference ΔH is an index indicating the flatness. If the height difference ΔH is 5 μm or less, the heat transfer resistance is sufficiently small, and the inclination of the light emitting element is also effectively suppressed. .

  In addition, the larger the diameter of the thermal via 6, the more the conductor paste flows when the green sheet is baked to form the thermal via 6, and the surface flatness of the formed thermal via 6 may be lowered. Therefore, when the thermal via 6 contains silver, it is preferable that the layer with the larger diameter of the thermal via 6, that is, the layer on the non-mounting surface 23 side, has a larger silver content in the conductor paste. Thereby, the conductor paste is less likely to flow in the layer on the non-mounting surface 23 side, and deformation of the thermal via 6 can be prevented.

  That is, it is preferable that the thermal via 6 has a larger silver content in the conductor paste as the diameter of the thermal via 6 is larger, that is, as the layer is closer to the non-mounting surface 23 side.

  With such a configuration, the flatness of the mounting surface 21, particularly the mounting portion 22, can be improved, the heat transfer resistance can be reduced, and the inclination when the light emitting element is mounted can be suppressed.

  The thermal via 6 does not necessarily have to be directly below the mounting portion 22 and may be provided in the vicinity thereof. Further, the thermal via 6 is not necessarily smaller than the mounting portion 22, and may have a size substantially the same as that of the mounting portion 22.

  Further, as shown in FIG. 6, for example, the mounting portion 22 may be provided with a glass film 8 having a surface roughness Ra of 0.1 μm or less. FIG. 6 is a cross-sectional view showing another example of the element substrate 1 on which the glass film 8 is provided. Since the surface roughness Ra of a general LTCC substrate is about 0.5 μm, the flatness can be further improved by providing such a glass film 8 on the mounting portion 22. The surface roughness Ra is the arithmetic average roughness Ra, and the value of the arithmetic average roughness Ra is represented by 3 “Definition and display of defined arithmetic average roughness” of JIS: B0601 (1994). It is what is done.

  When the semiconductor element to be mounted is a light emitting element, the mounting portion 22 may be provided with a silver reflecting film for the purpose of reflecting the light emitted from the light emitting element as far forward as possible. As a constituent material of the reflective film, silver is preferably used from the viewpoint of economy and reflectance. When the reflective film is silver, a glass film (also referred to as a glass overcoat film) may be provided on the surface so as to cover the silver reflective film in order to prevent oxidation and sulfurization of silver.

  As described above, the element substrate 1 according to the present embodiment has been described with reference to an example. However, the configuration can be appropriately changed as long as it is not contrary to the gist of the present invention. As already described, the number and arrangement of the thermal vias 6 can be changed as appropriate. The mounting surface 21 may be provided with a frame (reflector) that reflects light from the light emitting element, for example.

  In addition, the vertical cross section of the thermal via 6 in the direction penetrating the substrate body 2 may not be circular, and may be rectangular, for example. When the vertical cross section of the thermal via 6 in the direction penetrating the substrate body 2 is a rectangular shape, the length of each side of each layer, for example, constituting the rectangle is from the mounting surface side outermost layer 2-1 to the non-mounting surface side. What is necessary is just to increase to the outermost layer 2-6 sequentially. However, it is preferable that the vertical cross section of the thermal via 6 in the direction penetrating the substrate body 2 has a circular shape for reasons such as easy fabrication of the mold.

  In the light emitting device 10 according to the present embodiment, for example, as shown in FIG. 7, a light emitting element 11 such as an LED element is mounted on the mounting portion 22 of the element substrate 1. FIG. 7 is a cross-sectional view illustrating an example of the light-emitting device 10 according to the present embodiment. The light emitting element 11 is fixed to the mounting portion 22 with an adhesive 12, and an electrode (not shown) is electrically connected to the connection terminal 3 by a bonding wire 13. The light emitting device 10 is configured by providing a molding material 14 so as to cover the light emitting element 11 and the bonding wire 13.

  According to the light emitting device 10 according to the present embodiment, the heat transfer resistance of the formed thermal via 6 is formed even when the position of the through hole of each layer is displaced when the green sheet is laminated to form a laminated body. Can be prevented. Therefore, an excessive temperature rise of the light emitting element 11 can be suppressed and light can be emitted with high luminance. In addition, the diameter of the thermal via 6 on the mounting surface 21 can be set to an appropriate range for improving the surface flatness while preventing an increase in the heat transfer resistance of the thermal via 6. Thereby, since the inclination of the light emitting element 11 is suppressed, the damage and the optical axis shift can be suppressed. Such a light emitting device 10 according to the present embodiment can be suitably used as a backlight such as a mobile phone or a large liquid crystal display, an illumination for automobiles or decoration, and other light sources.

  Next, with reference to FIG. 8, the manufacturing method of the element substrate according to the present embodiment will be described. FIG. 8 is a diagram schematically showing a part of the process in the method for manufacturing an element substrate according to the present embodiment. In the following description, the members used for the manufacture will be described with the same reference numerals as those of the finished product.

  The element substrate 1 can be obtained, for example, as shown in FIG. First, the unfired mounting surface side outermost layer member 2-1, the unfired main body members 2-2 to 2-5, and the unfired unmounted surface side outermost layer in which the unfired thermal vias 6 having different diameters are formed. The member 2-6 is manufactured, these are laminated | stacked, a laminated body is formed, and the formed laminated body is made into the board | substrate 1 for unbaking elements. The element substrate 1 can be obtained by degreasing and firing the unfired element substrate 1.

  The unsintered mounting surface side outermost layer member 2-1 forms the unsintered thermal via 61 on the mounting surface side outermost layer green sheet 2a-1, for example, and unsintered connection terminals 3 and unsintered throughs on the mounting surface 21. It can be manufactured by forming the conductor 5. For example, the unfired main body members 2-2 to 2-5 are provided with unfired thermal vias 62, 63, 64, and 65 in four main body green sheets 2a-2 to 2a-5 so as to penetrate both main surfaces thereof. It can be manufactured by forming.

  Further, the unfired non-mounting surface side outermost layer member 2-6 is formed, for example, on the non-mounting surface side outermost layer green sheet 2a-6 with unfired thermal vias 66 penetrating both main surfaces, It can be manufactured by forming the unfired external electrode terminal 4 and the unfired through conductor 5 on the non-mounting surface 23. Here, the unfired thermal via 6 is formed in the mounting surface side outermost layer green sheet 2a-1, the main body green sheet layers 2a-2 to 2a-5, and the non-mounting surface side outermost layer green sheet 2a-6. The diameters of the unfired thermal vias 61 to 66 are sequentially increased from the mounting surface side outermost layer 2-1 to the non-mounting surface side outermost layer 2-6.

  The mounting surface side outermost layer green sheet 2a-1, the main body green sheets 2a-2 to 2a-5, and the non-mounting surface side outermost layer green sheet 2a-6 can be manufactured as follows. First, a slurry is prepared by adding a binder, and if necessary, a plasticizer and a solvent to a glass ceramic composition containing glass powder and a ceramic filler. Then, the prepared slurry is formed into a sheet by a doctor blade method or the like and dried.

  The glass powder is not necessarily limited, but a glass transition point (Tg) of 550 ° C. or higher and 700 ° C. or lower is preferable. When the glass transition point (Tg) is less than 550 ° C., degreasing may be difficult. When the glass transition point (Tg) exceeds 700 ° C., the shrinkage start temperature becomes high and the dimensional accuracy may be lowered.

  Moreover, it is preferable that a crystal | crystallization precipitates when it bakes at 850 degreeC or more and 900 degrees C or less. 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 is 880 degrees C or less is preferable. When the crystallization peak temperature (Tc) exceeds 880 ° C., the dimensional accuracy may be lowered.

As such glass powder, for example, SiO ₂ is 57 mol% or more and 65 mol% or less, B ₂ O ₃ is 13 mol% or more and 18 mol% or less, CaO is 9 mol% or more and 23 mol% or less, and Al ₂ O ₃ is 3 mol% or more and 8 mol% or less. hereinafter, those containing less 0.5 mol% or more 6 mol% of at least one in total selected from _{K 2} O and Na ₂ O are preferred. By using such a thing, it becomes easy to improve the flatness of the mounting surface 21 more.

Here, SiO ₂ serves as a glass network former. When the content of SiO ₂ is less than 57 mol%, 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 mol%, the glass melting temperature and the glass transition point (Tg) may be excessively high. The content of SiO ₂ is preferably 58 mol% or more, more preferably 59 mol% or more, and particularly preferably 60 mol% or more. The content of SiO ₂ is preferably less 64 mol%, more preferably not more than 63 mol%.

B ₂ O ₃ is a glass network former. If the content of B ₂ O ₃ is less than 13 mol%, there is a possibility that the glass melting temperature or the glass transition point (Tg) becomes too high. On the other hand, when the content of B ₂ O ₃ exceeds 18 mol%, it is difficult to obtain a stable glass, and the chemical durability may be lowered. The B ₂ O ₃ content is preferably at least: 14 mol%, more preferably more than 15 mol%. _The content of B 2 _{O 3} is preferably less 17 mol%, more preferably not more than 16 mol%.

Al ₂ O ₃ is added to increase the stability, chemical durability, and strength of the glass. When the content of Al ₂ O ₃ is less than 3 mol%, the glass may become unstable. On the other hand, when the content of Al ₂ O ₃ exceeds 8 mol%, the glass melting temperature and the glass transition point (Tg) may be excessively high. The content of Al ₂ O ₃ is preferably 4 mol% or more, more preferably 5 mol% or more. Further, the content of _Al 2 _{O 3} is preferably less 7 mol%, more preferably at most 6 mol%.

  CaO is added to increase glass stability and crystal precipitation, and to lower the glass melting temperature and the glass transition point (Tg). If the CaO content is less than 9 mol%, the glass melting temperature may be excessively high. On the other hand, if the CaO content exceeds 23 mol%, the glass may become unstable. The content of CaO is preferably 12 mol% or more, more preferably 13 mol% or more, and particularly preferably 14 mol% or more. The CaO content is preferably 22 mol% or less, more preferably 21 mol% or less, and particularly preferably 20 mol% or less.

K ₂ O and Na ₂ O are added to lower the glass transition point (Tg). When K ₂ O and Na ₂ O summed content is less than 0.5 mol%, there is a possibility that the glass melting temperature or the glass transition point (Tg) becomes too high. On the other hand, when the total content of K ₂ O and Na ₂ O exceeds 6 mol%, 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 mol% or more and 5 mol% or less.

  In addition, glass powder 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 a glass transition point (Tg), are satisfy | filled. When it contains another component, it is preferable that the total content rate is 10 mol% or less.

  The glass powder can be obtained by producing a glass having the above glass 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 as a solvent. For the pulverization, for example, a pulverizer such as a roll mill, a ball mill, or a jet mill can be used.

The 50% particle size (D ₅₀ ) of the glass powder is preferably 0.5 μm or more and 2 μm or less. When the 50% particle size of the glass powder is less than 0.5 μm, the glass powder is likely to aggregate, making it difficult to handle and uniformly dispersing. On the other hand, when the 50% particle size of the glass powder exceeds 2 μm, the glass softening temperature may increase or the sintering may be insufficient. Adjustment of the particle size can be obtained, for example, by classifying as necessary after pulverization.

On the other hand, as the ceramic filler, those conventionally used for the production of LTCC substrates can be used without particular limitation. For example, alumina powder, zirconia powder, or a mixture of alumina powder and zirconia powder can be suitably used. The 50% particle size (D ₅₀ ) of the ceramic filler is preferably, for example, from 0.5 μm to 4 μm.

  By mixing and mixing such glass powder and ceramic filler, for example, glass powder is 30% by mass to 50% by mass and correspondingly ceramic filler is 70% by mass to 50% by mass. A ceramic composition can be obtained. Moreover, a slurry can be obtained by adding a binder and, if necessary, a plasticizer, a solvent, and the like to the glass ceramic composition.

  As the binder, for example, polyvinyl butyral, acrylic resin and the like can be suitably used. As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate and the like can be used. Moreover, as a solvent, organic solvents, such as toluene, xylene, butanol, can be used suitably.

  The slurry is formed into a sheet by a doctor blade method or the like, and dried to allow the mounting surface side outermost layer green sheet 2a-1, the main body green sheets 2a-2 to 2a-5, and the non-mounting surface side outermost layer. Green sheet 2a-6 can be manufactured. The green sheet 2a-1 for the mounting surface side outermost layer is formed with the unfired thermal via 61 and the unfired connection terminals 3 and the unfired through conductors 5 to form the unfired mounting surface side outermost layer member 2-1. And can.

  The green sheets 2a-2 to 2a-5 for the main body are filled with a conductive paste in through holes formed by a punching machine or the like, thereby forming unfired thermal vias 62 to 65 to form an unfired main body member 2-2. ~ 2-5. The green sheet 2a-6 for the non-mounting surface side outermost layer is formed with the unfired thermal via 66 and the unfired external electrode terminals 4 and the unfired through conductors 5 to form the unfired unmounted surface side outermost layer member. 2-6.

  The formation method of the unfired thermal via 6, the unfired external electrode terminal 4, and the unfired through conductor 5 is not particularly limited, and can be performed by applying and filling a conductor paste by a screen printing method. 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 described above, regarding the unfired thermal via 6, it is preferable that the silver content in the conductor paste is larger in the layer on the non-mounting surface 23 side. When filling the through hole with a conductor paste mainly composed of silver to form the unfired thermal via 6, the silver component in the conductor paste filling the through hole of the mounting surface side outermost surface green sheet 2a-1 Can be 85 mass%. Then, the green sheets 2a-2 to 2a-5 for the main body and the green sheet 2a-6 for the non-mounting surface side outermost layer penetrate from the mounting surface side outermost surface green sheet 2a-1 toward the non-mounting surface 23 side. The silver component in the conductor paste filling the holes can be sequentially increased by 1 to 2% by mass up to 95% by mass.

  Moreover, when providing the glass film 8, a glass paste is apply | coated by the screen printing method to the part used as the mounting part 22 of the unbaking mounting surface side outermost layer member 2-1, and the unbaking glass film 8 is formed. As the glass paste, a paste obtained by adding a vehicle such as ethyl cellulose to a glass powder and, if necessary, a solvent or the like can be used.

The glass powder is fired simultaneously with the unfired mounting surface side outermost layer member 2-1, the unfired main body members 2-2 to 2-5, and the unfired unmounted surface side outermost layer member 2-6. as long as the resulting glass, 50% particle size _{(D 50)} is preferably at 0.5μm or 2μm or less. Moreover, adjustment of the surface roughness Ra of the glass film 8 can be performed, for example with the particle size of this glass powder.

  Moreover, when providing a reflective film, the paste for conductive reflective films is apply | coated to the part used as the mounting part 22 of the unbaking mounting surface side outermost layer member 2-1 by a screen printing method, and an unbaking reflective film is formed. Specific examples of the constituent material of such a reflective film include silver, a silver palladium mixture, and a silver platinum mixture. In the present invention, silver is preferably used from the viewpoint of economy and reflectivity.

Further, when a glass overcoat film for protecting the reflective film is formed on the reflective film, glass powder composed of a desired component (for example, SiO ₂ : 81.6% in terms of mol%, B ₂ O). ₃ : 16.6%, K ₂ O: 1.8%, etc.), and a method of forming the paste by screen printing and baking it in the same manner as the reflective film.

  Here, the film thickness of the reflection film depends on the material of the reflection film and the design of the light emitting device using the light emitting element mounting substrate. For example, when a silver reflection film is used, sufficient reflection performance is obtained. Therefore, the thickness is preferably 5 μm or more, and is preferably 50 μm or less in consideration of economy, deformation due to a difference in thermal expansion coefficient from the substrate body, and the like. Similarly, the thickness of the glass overcoat film is preferably 5 to 50 μm.

  The unfired mounting surface side outermost layer member 2-1, the unfired main body members 2-2 to 2-5, and the unfired non-mounting surface side outermost layer member 2-6 were laminated and laminated, and integrated by thermocompression bonding. By forming a laminated body, the unfired element substrate 1 can be formed. At this time, the unfired element substrate 1 that is a laminated body has a through hole filled with a conductive paste, and is a green sheet made of a glass ceramic composition. It has a laminated structure in which a plurality of unfired main body members 2-2 to 2-5 and unfired non-mounting surface side outermost layer member 2-6 are laminated. Moreover, the diameter of the through-hole in each layer increases sequentially from the unfired mounting surface side outermost layer member 2-1 to the unfired non-mounting surface side outermost layer member 2-6.

  Thereafter, degreasing for removing the binder and the like is performed, and firing for sintering the glass ceramic composition and the like is performed to obtain the element substrate 1.

  Degreasing can be performed, for example, by holding at 550 ° C. for 5 hours. If the degreasing temperature is too low, the binder or the like may not be sufficiently removed. On the other hand, if the degreasing temperature is about 550 ° C. and the degreasing time is about 5 hours, the binder or the like can be sufficiently removed, and if it exceeds this, productivity and the like may be lowered.

  Moreover, baking can be performed by hold | maintaining for 20 minutes or more and 60 minutes or less at the temperature of 850 degreeC or more and 900 degrees C or less, for example, and it is preferable to perform especially at the temperature of 860 degreeC or more and 880 degrees C or less. If the firing temperature is less than 850 ° C. and the firing time is less than 20 minutes, a dense product may not be obtained. On the other hand, if the firing temperature is about 900 ° C. and the firing time is about 60 minutes, a sufficiently dense product can be obtained, and if it exceeds this, productivity and the like may be lowered. Moreover, when the conductor paste containing the metal powder which has silver as a main component is used, when a calcination temperature exceeds 880 degreeC, there exists a possibility that it may become impossible to maintain a predetermined shape, since it softens too much.

  As described above, the manufacturing method of the element substrate 1 has been described. However, the order of forming each part can be changed as appropriate as long as the element substrate 1 can be manufactured.

  In the present embodiment, the diameters of the thermal vias 61 to 66 in each layer of the element substrate 1 are sequentially increased from the unfired mounting surface side outermost layer member 2-1 to the unfired non-mounting surface side outermost layer member 2-6. An increasing example has been described. However, the specific relationship regarding the shape of the through hole is not limited to the example of the thermal via 6. Therefore, the diameter of the through conductor 5 in each layer of the element substrate 1 may sequentially increase from the unfired mounting surface side outermost layer member 2-1 to the unfired non-mounting surface side outermost layer member 2-6. . Thereby, when forming the laminated body by laminating the green sheets, it is possible to prevent the electrical resistance of the formed through conductor 5 from increasing even when the position of the through hole of each layer is displaced.

In the present embodiment, the example in which the light emitting element 11 is mounted on the element substrate 1 has been described. However, the element substrate 1 according to the present embodiment can be applied to an example in which various semiconductor elements such as a power semiconductor element having a large calorific value are mounted.
[Second embodiment]
Next, the element substrate and the light emitting device according to the second aspect will be described with reference to FIG. FIG. 9 is an enlarged sectional view showing the vicinity of the thermal via 6a in the element substrate 1a according to the present modification.

  In the element substrate 1a according to the second aspect, the diameter of the thermal vias 61 to 66 in each layer is from the mounting surface side outermost layer 2-1 to the non-mounting surface 23 within a predetermined distance L from the mounting surface 21. Will gradually increase.

  The mounting surface side outermost layer 2-1 in the second embodiment corresponds to a layer having a thermal via with a small diameter of the thermal via and a mounting surface side outermost layer in the present invention. Moreover, the non-mounting surface side outermost layer 2-6 in this modification corresponds to the outermost layer on the non-mounting surface side that is the surface opposite to the mounting surface in the present invention.

  The element substrate 1a includes a substrate body 2, a connection terminal 3, an external electrode terminal 4, a through conductor 5, and a thermal via 6a. Except for the point that the shape of the thermal via 6a is different, the element substrate 1a is described with reference to FIG. This can be performed in the same manner as the element substrate 1 according to the embodiment.

  In the element substrate 1a according to the second aspect, as shown in FIG. 9, the thermal via 6a is within a predetermined distance L from the mounting surface 21, and the diameter of the thermal vias 61 to 66 in each layer is the mounting surface side. It increases sequentially from the outermost layer 2-1 toward the non-mounting surface 23. And in the range which is larger than the predetermined distance L from the mounting surface 21, that is, outside the range of the predetermined distance L from the mounting surface 21, the diameters of the thermal vias 61 to 66 in each layer are substantially constant. The predetermined distance L can be 400 μm, for example. In the present specification, “substantially constant” means that the difference in diameter is less than 5 μm.

  In the example shown in FIG. 9, the diameters D <b> 1 to D <b> 3 of the thermal vias 61 to 63 are within a predetermined distance L from the mounting surface 21, and the mounting surface side outermost layer (first layer) 2-1 to the third layer. Sequentially increases to 2-3. Outside the range of the predetermined distance L from the mounting surface 21, the diameter of the thermal vias 64 to 66 is substantially constant from the fourth layer 2-4 to the non-mounting surface side outermost layer (sixth layer) 2-6. is there.

  Thereby, when forming the laminated body by laminating the green sheets, the contact area between the thermal vias 61 to 66 in each layer is reduced even when the position of the through hole of each layer is displaced, or in each layer Disconnection between the thermal vias 61 to 66 can be prevented. And the increase in the heat transfer resistance of the formed thermal via 6a can be prevented.

  Also in the second aspect, the diameter D1 of the thermal via 61 in the mounting surface side outermost layer 2-1 is preferably 100 μm or more and 200 μm or less. Thereby, heat dissipation is securable without reducing the surface flatness of the conductor paste.

  Also in the second aspect, it is preferable that the difference in the diameter of the thermal via 6a between two layers in contact with each other is 30 μm or more and 60 μm or less. In the example shown in FIG. 9, both D2-D1 and D3-D2 are preferably 30 μm or more and 60 μm or less. Thereby, it is possible to prevent disconnection of the thermal via 6a due to misalignment when the green sheets are stacked while securing the degree of freedom of arrangement of the thermal via 6a.

  Also in the second aspect, the thickness T of each of the plurality of layers is preferably 70 μm or more and 200 μm or less. Accordingly, when the green sheet is handled, the green sheet can be prevented from being cut or stretched, and the through-hole formed in the green sheet can be sufficiently filled with the conductor paste.

  Also in the second aspect, the diameter D1 of the thermal via 61 in the mounting surface side outermost layer 2-1 is preferably 100 μm or more and 200 μm or less. Thereby, the height difference ΔH between the highest portion and the lowest portion of the mounting surface 21 in the vicinity of the thermal via 6a can be reduced to 5 μm or less.

  Also in the second aspect, it is preferable that the thermal via 6a has a higher silver content in a layer having a larger diameter of the thermal via 6a. Thereby, the flatness of the mounting surface 21, particularly the mounting portion 22, can be improved, the heat transfer resistance can be reduced, and the inclination when the light emitting element is mounted can be suppressed.

  In the light emitting device in which the light emitting element is mounted on the element substrate 1a according to the second aspect, the diameters of the thermal vias 64 to 66 are constant in a range that is larger than the predetermined distance L from the mounting surface 21. For example, the light emitting device 10 according to the embodiment described with reference to FIG.

  In the method for manufacturing the element substrate according to the second aspect, as shown in FIG. 8 except that the diameter of the unfired thermal vias 64 to 66 is constant in a range that is larger than the predetermined distance L from the mounting surface 21. This can be performed in the same manner as the device substrate manufacturing method according to the embodiment described above.

  That is, also in the second embodiment, the unfired element substrate 1a has a through-hole filled with a conductive paste, and is a green sheet made of a glass ceramic composition. It is a laminated body formed by laminating a plurality of layers including unfired main body members 2-2 to 2-5 and unfired non-mounting surface side outermost surface layer member 2-6. However, in the second mode, within the range of a predetermined distance L from the mounting surface 21, the unfired thermal vias 61 to 63 in the layers from the mounting surface side outermost surface green sheet 2 a-1 to the main body green sheet 2 a-3. The diameters D1 to D3 increase sequentially from the mounting surface side outermost surface green sheet 2a-1 to the main body green sheet 2a-3. And in the range which exists in the distance larger than the predetermined distance L from the mounting surface 21, the diameter of the unfired thermal vias 64-66 in each layer of the green sheet 2a-3 for the main body to the green sheet 2a-6 for the non-mounting surface side outermost layer Is constant.

  Also in the second aspect, the specific relationship regarding the shape of the through hole is not limited to the example of the thermal via 6a. The diameter of the through conductor 5 in each layer of the element substrate 1a is sequentially increased from the mounting surface 21 to the non-mounting surface 23 within a range of the predetermined distance L from the mounting surface 21, and is larger than the predetermined distance L from the mounting surface 21. In a range within the distance, the diameter of the through conductor 5 in each layer may be substantially constant. Thereby, when forming the laminated body by laminating the green sheets, it is possible to prevent an increase in electrical resistance of the formed through conductor 5 even when the position of the through hole of each layer is displaced.

  The element substrate 1a according to the second aspect can also be applied to an example in which various semiconductor elements such as a power semiconductor element having a large calorific value are mounted.

As a modified form of the second aspect, there is an aspect in which the thermal via diameter of the 2-6 layer is larger than the thermal via diameter of the 2-5 layer (second aspect A) in the second aspect. Further, the thermal via diameter is substantially the same within a predetermined distance L from the mounting surface 21, and the thermal via diameter sequentially increases from the mounting surface side toward the non-mounting surface side in the lower layer (first). 2B).
[Third aspect]
Next, the element substrate and the light emitting device according to the third aspect will be described with reference to FIG. FIG. 10 is an enlarged cross-sectional view showing the vicinity of the thermal via 6b in the element substrate 1b according to the third aspect.

  In the element substrate 1b according to the third aspect, the diameter of the thermal via 6b in the second layer 2-2 is in the third layer 2-3 in contact with the non-mounting surface side 23 of the second layer 2-2. The diameter is smaller than the diameter of the thermal via 6b.

  The element substrate 1b includes a substrate body 2, a connection terminal 3, an external electrode terminal 4, a through conductor 5, and a thermal via 6b. Except for the difference in the shape of the thermal via 6b, for example, an explanation will be given with reference to FIG. This can be performed in the same manner as the element substrate 1 according to the embodiment.

  In the element substrate 1b according to the third aspect, as shown in FIG. 10, the thermal vias 61 and 62 in each of the mounting surface side outermost layer (first layer) 2-1 and the second layer 2-2 are formed. The diameter is substantially constant. The diameter D2 of the thermal via 63 in the third layer 2-3 in contact with the non-mounting surface 23 side of the second layer 2-2 is larger than the diameter D1 of the thermal via 62 in the second layer 2-2. . The diameter D3 of the thermal via 64 in the fourth layer 2-4 in contact with the non-mounting surface 23 side of the third layer 2-3 is larger than the diameter D2 of the thermal via 63 in the third layer 2-3. . The diameters of the thermal vias 64 to 66 in each layer from the fourth layer 2-4 to the non-mounting surface side outermost layer (sixth layer) 2-6 are substantially constant.

  Thereby, when the green sheet is laminated to form a laminated body, the positions of the through holes in the respective layers on the non-mounting surface 23 side from the second layer 2-2 are also displaced. The contact area between 66 can be reduced, or disconnection between the thermal vias 62 to 66 in each layer can be prevented. And the increase in the heat transfer resistance of the formed thermal via 6b can be prevented.

  Also in the third aspect, the diameters of the thermal vias 61 and 62 in each of the mounting surface side outermost layer 2-1 and the second layer 2-2 are preferably 100 μm or more and 200 μm or less. Thereby, heat dissipation is securable without reducing the surface flatness of the conductor paste.

  Also in the third mode, the difference in the diameter of the thermal via 6b between the second layer 2-2 and the third layer 2-3 and the third layer 2-3 and the fourth layer 2-4 The difference in the diameter of the thermal via 6b is preferably 30 μm or more and 60 μm or less. In the example shown in FIG. 10, both D2-D1 and D3-D2 are preferably 30 μm or more and 60 μm or less. Thereby, it is possible to prevent disconnection of the thermal via 6b due to misalignment when the green sheets are stacked while securing the degree of freedom of arrangement of the thermal via 6b.

  Also in the third aspect, the thickness T of each of the plurality of layers is preferably 70 μm or more and 200 μm or less. Accordingly, when the green sheet is handled, the green sheet can be prevented from being cut or stretched, and the through-hole formed in the green sheet can be sufficiently filled with the conductor paste.

  Also in the third aspect, it is preferable that the diameter of the thermal via 6b in each layer from the mounting surface side outermost layer 2-1 to the second layer 2-2 is 100 μm or more and 200 μm or less. Thereby, the height difference ΔH between the highest part and the lowest part of the mounting surface 21 in the vicinity of the thermal via 6b can be reduced to 5 μm or less.

  In the third mode, the thermal via 6b has a larger silver content in the layer having the larger diameter of the thermal via 6b, that is, the silver content in the thermal via 63 in the third layer 2-3 is as follows. The silver content of the thermal via 62 in the second layer 2-2 is preferably larger. Thereby, the flatness of the mounting surface 21, particularly the mounting portion 22, can be improved, the heat transfer resistance can be reduced, and the inclination when the light emitting element is mounted can be suppressed.

  In the light emitting device in which the light emitting element is mounted on the element substrate 1b according to the third aspect, the diameters of the thermal vias 61 and 62 in each of the mounting surface side outermost layer 2-1 and the second layer 2-2 are constant. Except for the point that the diameters of the thermal vias 64 to 66 in each layer are constant from the fourth layer 2-4 to the non-mounting surface side outermost layer 2-6, for example, the embodiment described with reference to FIG. This can be the same as the light emitting device 10 according to the embodiment.

  In the device substrate manufacturing method according to the third aspect, the diameters of the unfired thermal vias 61 and 62 in each of the mounting surface side outermost layer 2-1 and the second layer 2-2 are constant, The element substrate according to the embodiment described with reference to FIG. 8 except that the diameter of the unfired thermal vias 64 to 66 in each layer is constant from the layer 2-4 to the non-mounting surface side outermost layer 2-6. This can be done in the same way as the manufacturing method.

  That is, also in the third aspect, the unfired element substrate 1b has a through hole filled with a conductive paste, and is a green sheet made of a glass ceramic composition. It is a laminated body formed by laminating a plurality of layers including unfired main body members 2-2 to 2-5 and unfired non-mounting surface side outermost surface layer member 2-6. However, in the third aspect, the diameters of the unfired thermal vias 61 and 62 in the layers of the mounting surface side outermost layer green sheet 2a-1 and the main body green sheet 2a-2 are constant.

  The diameter D2 of the unfired thermal via 63 in the main body green sheet 2a-3 in contact with the non-mounting surface 23 side of the main body green sheet 2a-2 is equal to the diameter of the unfired thermal via 62 in the main body green sheet 2a-2. Greater than D1. Further, the diameter D3 of the unfired thermal via 64 in the main body green sheet 2a-4 in contact with the non-mounting surface 23 side of the main body green sheet 2a-3 is equal to the diameter of the unfired thermal via 63 in the main body green sheet 2a-3. Greater than D2. Further, the diameter of the unfired thermal vias 64 to 66 in each layer is constant from the main body green sheet 2 a-4 to the non-mounting surface side outermost layer 2-6.

  In the third aspect, the specific relationship regarding the shape of the through hole is not limited to the example of the thermal via 6b, and the diameter of the through conductor 5 in the second layer 2-2 of the element substrate 1b is not limited. The diameter of the through conductor 5 in the third layer 2-3 in contact with the non-mounting surface side of the second layer 2-2 may be smaller. Thereby, when forming the laminated body by laminating the green sheets, it is possible to prevent an increase in electrical resistance of the formed through conductor 5 even when the position of the through hole of each layer is displaced.

  The element substrate 1b according to the third aspect is also applicable to an example in which various semiconductor elements such as a power semiconductor element having a large calorific value are mounted.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not construed as being limited to the examples.
Example 1
First, the mounting surface side outermost surface green sheet 2a-1, the main body green sheets 2a-2 to 2a-5, and the non-mounting surface side outermost surface green sheet 2a-6 were manufactured. That, SiO ₂ is _60.4mol%, B 2 _{O 3} is 15.6mol%, _Al 2 _{O 3} is 6 mol%, CaO is 15mol%, _{K 2} O is 1 mol%, as Na ₂ O is 2 mol% The raw materials were blended and mixed. 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. This glass was pulverized with an alumina ball mill for 20 to 60 hours to produce a glass powder. In addition, ethyl alcohol was used as a solvent for pulverization.

  A glass ceramic composition was produced by blending and mixing the glass powder at 40% by mass and alumina filler (made by Showa Denko KK, trade name: AL-45H) at 60% by mass. 50 g of this glass ceramic composition, 15 g of an organic solvent (toluene, xylene, 2-propanol, 2-butanol mixed at a mass ratio of 4: 2: 2: 1), plasticizer (di-2-ethylhexyl phthalate) 2.5 g of polyvinyl butyral (trade name: PVK # 3000K, manufactured by Denka) as a binder and 5 g of a dispersant (trade name: BYK180, manufactured by Big Chemie) were further blended and mixed to prepare a slurry.

  This slurry was applied onto a PET film by a doctor blade method, dried, and one layer of green sheet 2a-1 for mounting surface side outermost layer having a thickness after firing of 0.1 mm was produced. Similarly, four layers (2a-2 to 2a-5) of green sheets for a main body having a thickness after firing of 0.12 mm were produced. Furthermore, similarly, one layer of the non-mounting surface side outermost layer green sheet 2a-6 having a thickness after firing of 0.15 mm was manufactured.

  On the other hand, conductive 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 α-terpineol as a solvent so that the solid content is 85 mass%. Dispersed. Thereafter, kneading was carried out for 1 hour in a porcelain mortar, and further dispersed three times with three rolls to produce a conductor paste.

  A through hole is formed in the mounting surface side outermost surface green sheet 2a-1 using a hole punch, and a conductive paste is filled by a screen printing method to form an unfired thermal via 61. An unfired through conductor 5 was formed to produce an unfired mounting surface side outermost layer member 2-1. The body green sheets 2a-2 to 2a-5 are formed with through holes using a punching machine, filled with a conductive paste by a screen printing method to form unfired thermal vias 62 to 65, and the unfired body member 2 -2 to 2-5 were produced. Further, through holes are formed in the non-mounting surface side outermost surface green sheet 2a-6 using a hole punch, and a conductive paste is filled by a screen printing method to form an unfired thermal via 66. An electrode terminal 4 and an unfired through conductor 5 were formed to produce an unfired unmounted surface-side outermost layer member 2-6.

  Here, the diameter of the through hole of the green sheet 2a-1 for the mounting surface side outermost layer is 100 μm, and the diameters of the through holes of the four-layer green sheets 2a-2 to 2a-5 for the main body are 130 μm, 160 μm, and 160 μm, respectively. 160 μm, and the diameter of the through hole of the non-mounting surface side outermost surface green sheet 2 a-6 was 190 μm.

Then, from the lower layer side, one layer of unfired non-mounting surface side outermost layer member 2-6, four layers of unfired main body members 2-5 to 2-2, and one layer of unfired mounting surface side outermost layer member 2- By laminating and laminating 1 and forming a laminated body integrated by thermocompression bonding, a substrate 1 for an unfired element was obtained. Thereafter, degreasing was carried out by holding at 550 ° C. for 5 hours, and further holding at 870 ° C. for 30 minutes and firing to produce an element substrate.
(Comparative Example 1)
In the substrate main body 102, the element substrate 101 having a conventional structure was manufactured so that the diameters of the thermal vias 106 in each layer were substantially equal. That is, the penetration in the one mounting surface side outermost surface green sheet 102a-1, the four layers main body green sheets 102a-2 to 102a-5, and the one non-mounting surface side outermost surface green sheet 102a-6. Manufacture was carried out in the same manner as in Example 1 except that all the diameters of the holes were equally set to 150 μm.

  Next, regarding the element substrates of Example 1 and Comparative Example 1, the height difference ΔH of the mounting portion and, when a glass film was provided, the surface roughness Ra thereof was measured with a surface roughness meter.

  Moreover, the LED element was mounted on the element substrate of Example 1 and Comparative Example 1, and the thermal resistance was measured. That is, six LED elements (product name: GQ2CR460Z, manufactured by Showa Denko KK) are connected in series to the mounting portion and fixed with a die bond material (product name: KER-3000-M2 manufactured by Shin-Etsu Chemical Co., Ltd.). Furthermore, it was sealed with a sealant (Shin-Etsu Chemical Co., Ltd., trade name: SCR-1016A).

  About the element | substrate board | substrate with which this LED element was mounted, the thermal resistance was measured using the thermal resistance measuring device (The product made from Fluorescence sound electric company, brand name: TH-2167). The applied current was set to 35 mA, current was applied until the voltage drop saturated, and the saturation temperature Tj (° C.) was calculated from the dropped voltage and the temperature coefficient derived from the temperature-voltage drop characteristics of the LED element.

  Table 1 shows the measurement results of the height difference ΔH, the surface roughness Ra of the glass film, and the thermal resistance in the mounting portion in Example 1 and Comparative Example 1.

尚、熱抵抗は実施例１の測定値を１００とした時の結果を比較例１に示した。熱抵抗は大きくなるほど伝熱抵抗が悪く、小さければ伝熱抵抗が良い。

In addition, the thermal resistance is shown in Comparative Example 1 when the measured value of Example 1 is 100. The larger the heat resistance, the worse the heat transfer resistance, and the smaller the heat resistance, the better the heat transfer resistance.

  As is apparent from Table 1, it was confirmed that the height difference ΔH and the thermal resistance of the element substrate 101 of Comparative Example 1 having a conventional structure were increased as a whole. On the other hand, for the element of Example 1, the diameter of the thermal vias 61 to 66 in each layer increases in at least two layers in contact with each other among the mounting surface side outermost layer 2-1 to the non-mounting surface side outermost layer 2-6. Regarding the substrate 1, it was confirmed that the height difference ΔH was suppressed as a whole and the thermal resistance was also lowered. This is because when a green sheet is laminated to form a laminate, the contact area between the thermal vias 6 in each layer is reduced or the thermal vias in each layer are reduced even if the positions of the through holes in each layer are displaced. This is because it is possible to prevent disconnection between the six.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

DESCRIPTION OF SYMBOLS 1 Element board | substrate 2 Board | substrate body 3 Connection terminal 4 External electrode terminal 5 Through-conductor 6 Thermal via 7 Land 8 Glass film 10 Light-emitting device 11 Light-emitting element 12 Adhesive 13 Bonding wire 14 Mold material 21 Mounting surface 22 Mounting part 23 Non-mounting surface

Claims (10)

A substrate body comprising a sintered body of a glass ceramic composition containing glass powder and a ceramic filler, and having a mounting surface on which a semiconductor element is mounted;
A thermal via provided in the substrate body so as to penetrate from the mounting surface to a non-mounting surface opposite to the mounting surface, and having a plurality of layers stacked from the mounting surface toward the non-mounting surface; Have
The element substrate, wherein the thermal via has a diameter of the thermal via on the mounting surface side smaller than the diameter of the thermal via on the non-mounting surface side in at least two arbitrary layers that are in contact with each other among the laminated layers. .   The element substrate according to claim 1, wherein the layer having a thermal via having a small diameter is an outermost layer on the mounting surface side.   3. The element according to claim 2, wherein the thermal via has a diameter within a predetermined distance from the mounting surface, and the diameter of the thermal via in each layer sequentially increases from the outermost layer on the mounting surface side toward the non-mounting surface. Substrate.   4. The element substrate according to claim 3, wherein the diameter of the thermal via in each layer increases sequentially from the outermost layer on the mounting surface side to the outermost layer on the non-mounting surface side.   5. The element substrate according to claim 1, wherein a difference in diameter of the thermal via in two layers in contact with each other is 30 μm or more and 60 μm or less.   A diameter of the thermal via in a layer having a thermal via having a small diameter is 100 μm or more and 200 μm or less, and a height difference between the highest part and the lowest part of the mounting surface in the vicinity of the thermal via is 5 μm or less. The element substrate according to any one of claims 1 to 5.   The element substrate according to any one of claims 1 to 6, wherein the thermal via includes silver, and a layer having a larger diameter of the thermal via has a larger silver content in the thermal via in the layer. .   The element substrate according to claim 1, wherein the semiconductor element is a light emitting element. A device substrate according to claim 8,
A light emitting device having the light emitting element mounted on the mounting surface. It consists of a sintered body of a glass ceramic composition containing glass powder and ceramic filler, and has a substrate body having a mounting surface on which a semiconductor element is mounted, and penetrates from the mounting surface to a non-mounting surface opposite to the mounting surface And a thermal via formed by laminating a plurality of layers from the mounting surface toward the non-mounting surface, and the thermal via is at least arbitrarily in contact with each other among the layers to be stacked In the two layers, the diameter of the thermal via on the mounting surface side is smaller than the diameter of the thermal via on the non-mounting surface side.
Having a through-hole filled with a conductive paste containing metal powder and glass powder, and having a firing step of firing a laminate formed by laminating a plurality of green sheets made of the glass ceramic composition;
In the laminated body, in at least any two layers in contact with each other, the diameter of the through hole in the green sheet on the mounting surface side is smaller than the diameter of the through hole in the green sheet on the non-mounting surface side Manufacturing method.

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