WO2012057234A1

WO2012057234A1 - Substrate for light-emitting element, and light emitting device

Info

Publication number: WO2012057234A1
Application number: PCT/JP2011/074726
Authority: WO
Inventors: 勝寿中山
Original assignee: 旭硝子株式会社
Priority date: 2010-10-27
Filing date: 2011-10-26
Publication date: 2012-05-03
Also published as: JP5958342B2; JPWO2012057234A1; TW201233265A

Abstract

Provided are: a substrate for a ceramic light-emitting element that has a concave section with reduced warpage of the entire substrate; and a light-emitting device using same that has highly reliable light directivity and electrical connectivity. The substrate for the light-emitting element has: a plate-shaped base with a flat main surface comprising a first inorganic insulating material; a frame comprising a second inorganic insulating material bonded to the upper side main surface of the base; and a mounting section for the light-emitting element in the bottom surface of the concave section, which is formed by using part of the upper side main surface of the base as the bottom surface thereof and an inside wall surface of the frame as the side surface thereof. The substrate for the light-emitting element is characterized by: being arranged on top of the concave section bottom surface, between the frame and the base and with at least part thereof straddling the outer circumference of the concave section bottom surface; and by having a metal layer provided so as to not touch the outer edge of the base.

Description

Light emitting element substrate and light emitting device

The present invention relates to a light emitting element substrate and a light emitting device using the same.

Conventionally, a wiring board for mounting a light-emitting element such as a light-emitting diode element has a structure in which a wiring conductor layer is disposed on or inside an insulating substrate. A typical example of this wiring substrate is an insulating substrate made of alumina ceramic (hereinafter referred to as an alumina substrate). In this alumina substrate, a recess for accommodating a light emitting element is formed in the upper part, and a plurality of wiring conductor layers made of refractory metal powder such as tungsten and molybdenum are disposed on the surface and inside thereof, In some cases, the wiring conductor layer is electrically connected to the light emitting element housed in the recess. A wiring board on which such a light emitting element is mounted (hereinafter also referred to as a light emitting element substrate or simply a substrate) further dissipates heat generated by the light emitting element quickly, or the light emitting element emits light. A metal layer is often provided for purposes other than electrical connection, such as reflecting light as far forward as possible.

In addition to alumina substrates, low temperature co-fired ceramics (Low Temperature Co-fired Ceramics, hereinafter) can be used as light-emitting element substrates in addition to alumina substrates because of low temperature firing, low dielectric constant and high electrical conductivity copper and silver wiring. , Indicated as LTCC) has been proposed.

The substrate for a light-emitting element having the recess is generally a green sheet having at least a flat plate-like green sheet (also referred to as a ceramic substrate precursor) that constitutes the bottom surface of the recess and a through-hole that constitutes the wall of the recess. It is manufactured by firing a laminate in which (also referred to as a ceramic frame precursor) is laminated. At this time, the wiring conductor layer is formed on the surface or inside of each green sheet before or after the green sheet is laminated, and is fired at the same time as the green sheet is fired. The ceramic substrate precursor and the ceramic frame precursor described above may be composed of a single layer or a plurality of layers.

Here, in the light emitting element substrate having the recesses manufactured in this way, stress concentration or the like due to firing shrinkage occurs in the above manufacturing process, and the center of the flat ceramic substrate constituting the recess bottom surface of the obtained substrate There was a problem that the club was warped. If a substrate with this warpage is used, when the light emitting element is mounted on the substrate, the mounting position of the light emitting element or the position of the bonding wire is shifted and disconnection occurs, the light emitting element is mounted with an inclination and the light directivity is affected. It was a problem in terms of, etc. In addition, when this board is mounted on a printed wiring board or the like using solder, a warp on the back side of this board may cause a gap between the board and the solder, which may cause disconnection or prevent heat dissipation. There was a problem of becoming.

In order to solve the problem of warpage of the light emitting element substrate having the concave portion, for example, in Patent Document 1, a ceramic member having a flat ceramic substrate constituting the bottom surface of the concave portion and a through hole constituting the wall portion of the concave portion The method of forming a layer made of a ceramic material having a different shrinkage from the ceramic material constituting the other part in the vicinity of the interface between the two is employed.

In Patent Document 2 and Patent Document 3, a plurality of green sheets including a thin green sheet having a through-hole in a portion corresponding to the bottom surface of the recess are laminated on the flat ceramic substrate constituting the bottom surface of the recess. In this way, while suppressing the warping of the central portion (the bottom surface of the recess), further recesses are formed, and the conductor layer is formed on the entire surface of the flat ceramic substrate or partially so as to fill the recesses. By doing so, the bottom surface of the recess is flattened.

Japanese Unexamined Patent Publication No. 2007-281108 Japanese Unexamined Patent Publication No. 2010-186880 Japanese Unexamined Patent Publication No. 2010-186881

The present invention has been made in order to solve the problem of warpage of a substrate for a light emitting element having the above-mentioned concave portion, and is a substrate for a light emitting element having a concave portion in which the amount of warpage of the entire substrate is reduced, and light using the same. An object of the present invention is to provide a light-emitting device with high reliability in terms of directivity and electrical connection.

The substrate for a light-emitting element of the present invention comprises a plate-like substrate having a flat main surface made of the first inorganic insulating material, and a frame made of the second inorganic insulating material bonded to the upper main surface of the substrate. A substrate for a light emitting element having a mounting portion for mounting a light emitting element on a bottom surface of a recess formed with a part of the upper main surface of the base as a bottom surface and an inner wall surface of the frame body as a side surface, Further, at least a part of the metal layer is disposed between the frame body and the base so as to straddle the outer periphery of the bottom surface of the recess, and has a metal layer disposed so as not to reach the outer edge of the base.

In the light emitting element substrate of the present invention, it is preferable that the metal layer is disposed between the frame body and the base so as to straddle the outer periphery of the bottom surface of the recess in the entire periphery. Alternatively, the total length of the outer periphery of the portion where the metal layer is disposed across the outer periphery of the bottom surface of the recess is preferably 40% or more with respect to the total outer peripheral length of the bottom surface of the recess. The distance (L) from the outer periphery of the bottom surface of the recess to the edge of the metal layer between the frame and the substrate is preferably 100 to 200 μm.
Unless otherwise specified, “to” indicating the numerical range described above is used to mean that the numerical values described before and after it are used as a lower limit value and an upper limit value, and hereinafter “to” Used with meaning.
In the substrate for a light-emitting element of the present invention, the metal layer has a function of reducing warpage of the entire substrate by being provided as described above, and the metal layer is electrically connected to, for example, an electrode of the light-emitting element. It can also serve as an element connection terminal, a heat dissipation layer, a reflective layer, or a base layer for forming a reflective layer. In this case, the metal layer is disposed between the frame body and the base so as to straddle the outer periphery of the bottom surface of the recess. Especially, it is preferable to provide the said metal layer as a reflection layer which can select the shape to arrange | position comparatively freely, or as a base layer for reflection layer formation.

Furthermore, in the substrate for a light emitting device of the present invention, the glass ceramic composition in which each of the first inorganic insulating material and the second inorganic insulating material constituting the base body and the frame body includes glass powder and ceramic powder, respectively. It is a sintered body, and the metal constituting the metal layer is preferably a metal mainly composed of silver.
In the substrate for a light emitting device of the present invention, the first inorganic insulating material and the second inorganic insulating material are both sintered bodies of an alumina ceramic composition, and the metal constituting the metal layer is tungsten and molybdenum. It is preferable that the main component is at least one selected from the group consisting of: Further, it is preferable to form a metal reflective layer mainly composed of silver on the metal layer mainly composed of at least one selected from the group consisting of tungsten and molybdenum.

The light-emitting device of the present invention includes the light-emitting element substrate of the present invention and a light-emitting element mounted on the light-emitting element substrate.

According to the present invention, it is possible to provide a light emitting element substrate in which the amount of warpage of the entire substrate is reduced in the light emitting element substrate having a recess. Further, according to the present invention, by mounting a light emitting element on such a light emitting element substrate, a light emitting device with high reliability in light directivity, electrical connection, and the like can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing which shows an example of embodiment of the board | substrate for light emitting elements of this invention, (a) is a top view, (b) is sectional drawing. It is drawing which shows another example of embodiment of the board | substrate for light emitting elements of this invention, (a) is a top view, (b) is sectional drawing. It is drawing which shows an example of the light-emitting device of this invention using the board | substrate for light emitting elements shown in FIG. 1, (a) is a top view, (b) It is sectional drawing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is limited to the following description and is not interpreted.

In the present specification, a plate-like substrate having a flat main surface refers to a substrate having a flat surface with a level at which both the upper and lower main surfaces can be recognized as a flat plate shape at the visual level. The term “substrate” refers to a substrate whose upper and lower main surfaces are such flat surfaces. Similarly, the abbreviations indicate levels that can be recognized as such on the visual level unless otherwise specified.

According to the present invention, in a light emitting element substrate made of an inorganic insulating material having a recess and having a light emitting element mounted on the bottom surface, at least a part of the substrate straddles the outer periphery of the recess bottom surface on the bottom surface of the recess. By having a metal layer disposed between the frame body and the base body constituting the bottom surface of the recess and disposed so as not to reach the outer edge of the base body, the amount of warpage of the substrate for the light emitting element, specifically, It is possible to reduce the rate of warping that goes up to the center. As a result, the bottom surface of the concave portion is flattened, the positional deviation and inclination of the light emitting element when mounting the light emitting element are reduced, the problem that the directivity of light is different from the design, and the occurrence of disconnection due to the positional deviation of the bonding wire. Can be suppressed. Further, when the light emitting element substrate is mounted on a printed wiring board or the like by using solder, problems such as disconnection and deterioration of heat dissipation, which are caused by the warpage of the substrate, can be reduced.

In the substrate for a light emitting device of the present invention, when an element connection terminal, a heat dissipation layer, a reflective layer, or a base layer for forming a reflective layer, which is usually provided on the bottom surface of the recess, is disposed, a part of the bottom surface of the recess If it can be provided so as to straddle the outer periphery of the substrate, it is not necessary to separately provide a metal layer for reducing the warpage of the entire substrate. That is, in the present invention, the metal layer for reducing warpage is usually formed by the element connection terminal, the heat dissipation layer, the reflection layer, or the reflection layer formed so that a part thereof straddles the outer periphery of the bottom surface of the recess. For the underlayer for the purpose. Especially, it is preferable to provide the said metal layer as a reflective layer which can select the shape to arrange | position relatively freely, or a base layer for reflective layer formation.
In the present invention, when the metal film disposed on the bottom surface of the recess in order to reduce the warpage of the substrate is used as a layer constituting the reflective layer, the metal layer of the reflective layer is used in the present invention. A metal layer may be used, and when a metal layer is used as a layer constituting the base layer, the metal layer of the base layer may be a metal layer in the present invention.

Further, as the first inorganic insulating material and the second inorganic insulating material constituting the substrate and the frame, respectively, specifically, an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, mullite And ceramics such as a sintered body of a glass ceramic composition containing glass powder and ceramic powder (hereinafter sometimes referred to as LTCC (low temperature co-sintered ceramic)). Since these ceramics have different firing temperatures, the substrate and the frame are usually made of the same kind of ceramic. In the present invention, as the first and second inorganic insulating materials, LTCC is preferable from the viewpoints of ease of manufacture, easy processability, economy, and the like. As long as the first and second inorganic insulating materials are made of the same kind of ceramics, for example, a glass ceramic composition capable of obtaining a high bending strength is applied to the base body in LTCC, and the frame body has diffuse reflectivity. The raw material composition of the glass powder or the ceramic powder may be different depending on the required characteristics of the base body and the frame so that the glass ceramic composition emphasized is applied.

Here, when LTCC is selected as the inorganic insulating material, a metal layer containing silver as a main component as the metal layer (for example, a metal layer or alloy containing 95% by mass or more of silver) can be fired at a low temperature. It is preferable to design a substrate for a light-emitting element using this as a reflective layer. Further, when high-temperature co-fired ceramics such as alumina ceramics are selected as the inorganic insulating material, high-temperature firing is necessary, so that the metal layer includes at least one refractory metal selected from the group consisting of tungsten and molybdenum. A metal layer made of a refractory metal as a main component is selected. Since these refractory metal layers formed to reduce the warpage of the substrate do not function sufficiently as a reflective layer, they are usually reflected using a highly reflective metal such as silver on the refractory metal layer after firing. Form a layer. When such a refractory metal layer is employed, the refractory metal layer is designed to function also as an underlayer.

As an example of an embodiment of the light emitting element substrate of the present invention, a light emitting element substrate in which the first and second inorganic insulating materials are each composed of a base body and a frame body made of LTCC, and the metal layer is designed as a reflective layer. This will be described below.

1A is a plan view showing an example of a light-emitting element substrate 1 for mounting one light-emitting element according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line XX in FIG. FIG.

The light emitting element substrate 1 has a substantially flat base 2 that is mainly composed of the light emitting element substrate 1 and has a substantially square shape when viewed from above. When the substrate 2 is used as a substrate for a light emitting element, it has an upper surface on which the light emitting element is mounted as a main surface 21, and in this example, the opposite surface is a back surface 23. The thickness, size, etc. of the substrate 2 are not particularly limited, and can be the same as that of a normal light emitting element wiring substrate. The light emitting element substrate 1 further includes a frame body 3 joined to the peripheral edge portion of the main surface 21 of the base body so as to form a concave portion 4 having a substantially circular portion at the center of the main surface 21 of the base body 2 as a bottom surface 24. . Note that the side surface 25 of the recess 4 is formed by the inner wall surface of the frame 3. In the light emitting element substrate 1, a substantially central portion of the recess bottom surface 24 is a mounting portion 22 on which the light emitting element is mounted.

Here, the side surface 25 of the recess 4 is provided substantially perpendicular to the bottom surface 24 thereof. That is, the frame body 3 is shaped so that the opening portions have the same shape in the upper and lower sides, and is joined to the peripheral edge portion of the substrate main surface 21. The shape of the frame 3 may be, for example, a taper-shaped side surface with a large upper opening and a small lower opening.

Specific numerical values of the distance between the side surface 25 of the concave portion 4 and the edge of the light emitting element mounting portion 22 include the output of the mounted light emitting element, the size (size), and, if necessary, for example, Depending on the type of phosphor to be contained in the sealing layer, which will be described later, its content, conversion efficiency, etc., for example, the distance at which the light emitted from the light emitting element is most efficiently emitted in the light extraction direction is used as an index. It may be used.

Further, the height of the side surface 25 of the concave portion 4, that is, the distance from the bottom surface 24 of the concave portion 4 to the highest position of the frame body 3 (that is, the height of the frame body 3) determines the light from the mounted light emitting element. The height is not particularly limited as long as it can be sufficiently reflected in the extraction direction. Specifically, depending on the design of the light emitting device, for example, the output of the light emitting element to be mounted, the distance from the edge of the light emitting element mounting portion, etc., the shape of the product on which the light emitting device is mounted and the wavelength conversion From the standpoint of efficiently filling a sealing material containing a phosphor for the purpose, it is preferable that the height is 100 to 500 μm higher than the height of the highest part of the light emitting element when the light emitting element is mounted. The height of the frame 3 is more preferably equal to or less than the height of 450 μm added to the height of the highest part of the light emitting element, and more preferably equal to or less than the height of 400 μm.

In this example, the base 2 and the frame 3 are both made of LTCC. With respect to the LTCC material constituting the substrate 2, for example, the bending strength of the substrate 2 and the frame 3 formed of the LTCC material is 250 MPa from the viewpoint of suppressing damage or the like when the light emitting element is mounted and thereafter used. The above is preferable. The LTCC material that constitutes the frame 3 is preferably the same as the material that constitutes the substrate 2 in consideration of adhesion to the substrate 2.

Further, depending on the required characteristics of the light emitting device, the LTCC material may be an LTCC material having diffuse reflectivity. The LTCC having diffuse reflectivity is not particularly limited as long as the light extraction efficiency is improved in the light emitting device. Preferably, a material capable of obtaining light extraction efficiency corresponding to the silver reflective film is used. A haze value measured by JIS K 7105 is used as an index for evaluating diffuse reflectance. The value is preferably 95% or more, and more preferably 98% or more.
The raw material composition, sintering conditions, and the like of the sintered body of the glass ceramic composition including the glass powder and the ceramic powder constituting the substrate 2 and the frame body 3 are as described later.

In the light emitting element substrate 1, the element connection terminals 5 electrically connected to the pair of electrodes of the light emitting element are provided on the concave bottom surface 24 formed by a part of the main surface 21 of the base 2. A pair of substantially rectangular shapes are provided so as to face the outer periphery of the element mounting portion 22, specifically, both sides.

A pair of external connection terminals 6 that are electrically connected to an external circuit are provided on the back surface 23 of the base 2, and the element connection terminals 5 and the external connection terminals 6 are electrically connected to the inside of the base 2. A pair of through conductors 7 is provided. About the element connection terminal 5, the external connection terminal 6, and the through conductor 7, as long as these are electrically connected by a route of the light emitting element → the element connection terminal 5 → the through conductor 7 → the external connection terminal 6 → the external circuit, The position and shape of the arrangement are not limited to those shown in FIG. 1 and can be adjusted as appropriate.

The constituent materials of the element connection terminal 5, the external connection terminal 6, and the through conductor 7 (hereinafter, collectively referred to as “wiring conductor”) are generally the same as those of the wiring conductor used for the light emitting element substrate. Any material can be used without particular limitation. Specific examples of the constituent material of these wiring conductors include metal materials mainly composed of copper, silver, gold, and the like. Among these metal materials, silver, a metal material composed of silver and platinum, or a metal material composed of silver and palladium is preferably used.

The element connection terminal 5 and the external connection terminal 6 are made of these metal materials, preferably on a metal layer having a thickness of 5 to 15 μm, and this layer is protected from oxidation and sulfidization and has conductivity. A configuration in which a protective layer (not shown) is formed so as to cover the whole including its edge is preferable. The conductive protective layer is not particularly limited as long as it is made of a conductive material having a function of protecting the metal layer. Specific examples include a conductive protective layer made of nickel plating, chrome plating, silver plating, nickel / silver plating, gold plating, nickel / gold plating, or the like.

In the present invention, among these, as a conductive protective layer for covering and protecting the element connection terminals 5 and the external connection terminals 6, for example, bonding wires and other connection materials used for connection with electrodes of light emitting elements to be described later It is preferable to use a metal plating layer having a gold plating layer as at least the outermost layer from the viewpoint of obtaining good bonding. The conductive protective layer may be formed of only a gold plating layer, but is more preferably formed as a nickel / gold plating layer obtained by performing gold plating on nickel plating. In this case, the thickness of the conductive protective layer is preferably 2 to 20 μm for the nickel plating layer and 0.1 to 1.0 μm for the gold plating layer.

The metal layer disposed to reduce the warpage in the light emitting element substrate of the present invention, in this example, the metal layer 8 that also functions as a reflective layer, is formed on the bottom surface 24 of the recess 4 on the pair of the bottom surfaces 24. It includes a region where the element connection terminal 5 is disposed and a region excluding the vicinity thereof, and an edge thereof is disposed between the frame 3 and the substrate 2 across the outer periphery A of the bottom surface 24 of the recess. It is arranged so as not to reach the outer edge. Here, the area where the element connection terminal 5 is disposed and the region excluding the vicinity thereof are specifically electrically insulated from the element connection terminal 5 and the metal layer 8, and further, at the time of lamination or printing This is a region that is considered so as not to cause deterioration of the insulation property or obstruction of the conductivity of the element connection terminal 5 due to a manufacturing defect such as positional misalignment, and preferably from the edge of the element connection terminal 5 It is a region outside 100 μm or more, and more preferably a region outside 150 μm from the edge.

As shown in FIG. 1, in the light emitting element substrate 1, the metal layer 8 has a similar shape (substantially circular shape) having the same center as the outer periphery of the bottom surface 24 of the recess 4, and straddles the entire outer periphery of the bottom surface 24. . Here, it is formed at a substantially circular edge. The distance L from the outer periphery of the bottom surface 24 of the recess 4 to the edge of the metal layer 8 is such that the warp of the light emitting element substrate is sufficiently reduced and the frame 3 and the base body 2 are joined with sufficient adhesion strength. It is selected as appropriate. Further, when taking into account the displacement (printing displacement) of the arrangement position of the metal layer 8 and the misalignment of the frame 3 and the substrate 2 when manufacturing the light emitting element substrate 1, the metal from the outer periphery of the bottom surface 24 of the recess 4. The distance L to the edge of the layer 8 is preferably 100 to 200 μm, more preferably 130 to 170 μm.

In the light emitting element substrate 1 shown in FIG. 1, the metal layer 8 is formed so that the edge extends over the entire outer periphery of the bottom surface 24 of the recess 4 and extends between the base 2 and the frame 3. However, as in the example shown in FIG. 2 to be described later, the metal layer 8 may be formed so that the edge of the metal layer 8 straddles a part of the outer periphery of the bottom surface 24 as necessary. In this example, since the metal layer 8 is disposed as a reflective layer, the metal layer 8 is disposed on the bottom surface 24 of the concave portion 4 as large as possible. However, the metal layer is not considered in light reflection performance. In the range which does not impair the effect of this invention, the shape of the metal layer 8 can be changed suitably.

The metal layer 8 is not particularly limited as long as the metal layer 8 has a property of suppressing the stress that deforms into a convex shape during firing faster than the base 2 from the viewpoint of reducing warpage of the light emitting element substrate 1. However, in the light emitting element substrate 1 shown in FIG. 1, the metal layer 8 also has a function as a reflection layer. Therefore, the metal material constituting the metal layer 8 can be fired simultaneously with the LTCC substrate and is light reflective. Further, a metal material containing silver as a main component (for example, a metal material containing 95% by mass or more of silver) is preferable. Specific examples of the metal material containing silver as a main component include silver, a metal material composed of silver and platinum, or a metal material composed of silver and palladium. Specific examples of the metal material composed of silver and platinum or the metal material composed of silver and palladium include a metal material in which the ratio of platinum or palladium to the total amount of the metal material is 5% by mass or less. Among these, the metal layer 8 comprised only of silver is preferable from the point which can obtain a high reflectance in this invention.

The film thickness of the metal layer 8 is preferably 5 to 15 μm, more preferably 8 to 12 μm. If the thickness of the metal layer 8 is less than 5 μm, sufficient strength and light reflectivity may not be obtained, and if it exceeds 15 μm, it is economically disadvantageous and heat with the base 2 and the frame 3 during the manufacturing process. There is a possibility that deformation due to an expansion difference occurs, and a reduction in warpage of the substrate cannot be sufficiently achieved.

Further, the light emitting element substrate 1 shown in FIG. 1 has an overcoat glass layer 9 for insulating and protecting the metal layer 8. The overcoat glass layer 9 covers the whole of the metal layer 8 including the edge of the metal layer 8 except for the portion extending between the base 2 and the frame 3 of the metal layer 8 formed on the bottom surface 24 of the recess 4. Is formed. Here, the edge of the overcoat glass layer 9 may be in contact with the element connection terminal 5 as long as the insulation between the element connection terminal 5 provided on the concave bottom surface 24 and the metal layer 8 is ensured. The distance between the two is preferably 75 μm or more, more preferably 100 μm or more, taking into account the occurrence of problems in manufacturing such as misalignment during lamination and printing.

In the portion where the edge of the metal layer 8 is covered with the overcoat glass layer 9, the distance between the edge of the metal layer 8 and the edge of the overcoat glass layer 9 is that the metal layer 8 is an external deterioration factor. It is preferable that the distance be as short as possible within a range that is sufficiently protected from. Specifically, 10 to 50 μm is preferable, and 20 to 30 μm is more preferable. When the distance is less than 10 μm, the metal layer 8 is exposed, and the metal material constituting the metal layer 8, particularly the metal material mainly containing silver, which is preferably used, is oxidized or sulfided, and the light reflectivity is lowered. If it exceeds 50 μm, as a result, the area of the region where the metal layer 8 is disposed is reduced, so that the light reflectivity is lowered.

Although the film thickness of the overcoat glass layer 9 depends on the design of the light emitting device, it is 5 to 50 μm in consideration of the manufacturing cost, the deformation due to the difference in thermal expansion from the substrate, etc. preferable. Moreover, it is preferable that the surface of the overcoat glass layer 9 has surface smoothness in order to obtain sufficient heat dissipation at least in the light emitting element mounting portion 22. Specifically, the surface roughness Ra is preferably 0.03 [mu] m or less, more preferably 0.01 [mu] m or less, from the viewpoint of manufacturing ease while ensuring sufficient heat dissipation. In addition, the raw material composition of the glass which comprises an overcoat glass layer is demonstrated in the below-mentioned manufacturing method.

In the light emitting element substrate 1 shown in FIG. 1, the overcoat glass layer 9 does not cover the metal layer 8 formed between the base 2 and the frame 3, but the effect of the present invention is not impaired. As long as necessary, the metal layer 8 formed between the base 2 and the frame 3 may be covered.

Although not shown in FIG. 1, a thermal via is embedded in the light emitting element substrate 1 in the direction perpendicular to the main surface 21 of the base 2 in the base 2 in order to reduce the thermal resistance. A heat dissipation layer may be arranged in a direction parallel to 21. The thermal via has a columnar shape smaller than the mounting portion 22, for example, and a plurality of thermal vias are provided immediately below the mounting portion 22. When providing a thermal via, it is preferable to provide it from the back surface 23 to the vicinity of the main surface 21 so as not to reach the main surface 21 of the base 2. By adopting such an arrangement, the flatness of the main surface 21, particularly the mounting portion 22, can be improved, the thermal resistance can be reduced, and the inclination when the light emitting element is mounted can be suppressed.

Next, as another example of the embodiment of the light emitting element substrate of the present invention, a light emitting element designed in exactly the same manner as the light emitting element substrate shown in FIG. 1 except that the region where the metal layer is formed is different. The substrate for use will be described.

FIG. 2 shows a light emitting element substrate 1 as an example different from the light emitting element substrate 1 shown in FIG. 1 of the light emitting element substrate 1 for mounting one light emitting element according to the embodiment of the present invention. FIG. 2 is a plan view (a) and a sectional view taken along line XX of FIG.

As described above, the light emitting element substrate 1 shown in FIG. 2 is the same as the light emitting element substrate 1 shown in FIG. 1 except for the region where the metal layer 8 is formed. Therefore, only the metal layer 8 will be described below.
In the light emitting element substrate 1 shown in FIG. 2, the metal layer 8 is provided to reduce the warpage of the light emitting element substrate and also serve as a reflective layer. The metal layer 8 includes, on the bottom surface 24 of the concave portion 4, a portion of the bottom surface 24 where the pair of element connection terminals 5 are disposed and a region excluding the vicinity thereof, and the edge of the metal layer 8 is partially Further, it is disposed between the frame 3 and the base 2 so as to straddle the outer periphery A of the bottom surface 24 of the recess, and is arranged in a substantially square shape so as not to reach the outer edge of the base 2. The region excluding the vicinity of the periphery of the element connection terminal 5 is the same as the region described in the light emitting element substrate 1 shown in FIG.

The shape of the outer edge of the metal layer 8 is a substantially similar shape (substantially square) with the same center as the shape of the base 2 as viewed from above, and each side constituting the outer edge of the metal layer 8 and the outer edge of the base 2 are formed. Each side is positioned so as to have a parallel relationship. As shown in FIG. 2, the metal layer 8 has a predetermined length and straddles the outer periphery at four locations of the substantially circular outer periphery A on the bottom surface 24 of the recess 4, and the edges of the metal layer 8 are the frame body 3 and the base body. It is formed to extend between two.

Here, the ratio of the metal layer 8 straddling the outer periphery A of the bottom surface 24 of the recess 4 is the length of the outer periphery of the four locations where the metal layer 8 straddles the entire outer peripheral length (b) (in FIG. 2). , A1, a2, a3, and a4), the total percentage ((a1 + a2 + a3 + a4) / b × 100) is preferably 40% or more, and more preferably 60% or more. In particular, the case where 100% (that is, everything) is straddled as shown in FIG. 1 is particularly preferable.

The shape of the metal layer 8 is not particularly limited as long as the ratio of the metal layer 8 straddling the outer periphery of the bottom surface 24 of the recess 4 is in the above range. By making the shape of the metal layer 8 into a substantially square shape as described above, it is preferable in that the ratio of the metal layer 8 straddling the outer periphery can be within the above range without considering the stacking deviation and printing deviation in detail. On the other hand, when the metal layer 8 is formed in a substantially square shape so that the ratio of straddling the outer periphery of the bottom surface 24 becomes 100%, the substantially circular metal layer shown in FIG. Although the same effect as that obtained is obtained, the area of the metal layer existing between the base 2 and the frame 3 is increased, which is not preferable for the adhesion between the base 2 and the frame 3.

In designing the metal layer 8 in this way, the light emitting element substrate itself and the characteristics required in manufacturing, for example, adhesion between the base 2 and the frame 3, warpage of the light emitting element substrate 1, ease of manufacture, etc. Accordingly, the shape of the metal layer, the ratio formed across the outer periphery of the bottom surface 24, the area of the metal layer formed between the base 2 and the frame 3, and the like are adjusted as appropriate. Specifically, it may be a polygonal metal layer. In the case of an n-polygon other than a substantially square, the total percentage of the length of the outer periphery of the portion where the metal layer 8 straddles the entire outer peripheral length (b) depends on the number of sides of the polygon. Calculated. For example, in the case of an n-polygon, the total length of each side of the outer periphery of the n-polygon that the metal layer straddles with respect to the total outer peripheral length (b) of the n-polygon (that is, each side of the outer periphery is c1. , C2, c3, c4,..., Cn, the percentage of c1 + c2 + c3 + c4... + Cn) (c1 + c2 + c3 + c4.

As described above, the embodiment of the light emitting element substrate of the present invention has been described. For example, the light emitting element 11 such as a light emitting diode element is mounted on the mounting portion 22 using the light emitting element substrate 1 shown in FIG. Thus, for example, the light emitting device 10 shown in FIG. 3 can be manufactured.

As shown in FIG. 3, the light emitting device 10 of the present invention has a light emitting diode element or the like mounted on a mounting portion 22 located substantially at the center of the bottom surface 24 of the recess 4 of the light emitting element substrate 1 by a die bond agent such as a silicone die bond agent. The light emitting element 11 is mounted, and a pair of electrodes (not shown) is connected to each of the pair of element connection terminals 5 by bonding wires 12. The light emitting device 10 is further configured by providing the sealing layer 13 so as to fill the concave portion 4 while covering the light emitting element 11 and the bonding wire 12 arranged as described above on the bottom surface 24 of the concave portion 4. ing. In addition, the material (sealing material) which comprises the sealing layer 13 may contain the fluorescent substance normally used for the sealing layer of a light-emitting device as needed.

Such a light-emitting device 10 of the present invention is a light-emitting element substrate having a recess and a light-emitting element mounted on the bottom surface thereof, and the light-emitting element substrate 1 of the present invention in which the ratio of warpage of the substrate itself is reduced. This is a light emitting device in which the positional deviation and inclination of the light emitting element are reduced and the problems such as the difference in the directivity of light from the design and the occurrence of disconnection due to the positional deviation of the bonding wire are suppressed. Further, when the light emitting device 10 is further mounted on a printed wiring board or the like by using solder, problems such as disconnection and deterioration of heat dissipation caused by the warping of the board can be reduced. Such a light-emitting device of the present invention can be suitably used as a backlight for a liquid crystal display of a mobile phone, a personal computer, or a flat television, for example, illumination for automobiles or decoration, general illumination, and other light sources.

As mentioned above, although the embodiment in the light emitting element substrate of the present invention and the light emitting device using the same has been described as an example, the light emitting element substrate and the light emitting device of the present invention are not limited thereto. As long as it does not contradict the spirit of the present invention, the configuration can be changed as necessary.

Hereinafter, a method for manufacturing a light emitting element substrate according to the present invention will be described using the light emitting element substrate 1 shown in FIG. 1 as an example. 1 can be manufactured by a manufacturing method including, for example, the following (A) green sheet manufacturing step, (B) paste layer forming step, (C) laminating step, and (D) firing step. . In addition, about the member used for manufacture, the same code | symbol as the member of a finished product is attached | subjected and demonstrated. For example, the base and the green sheet for the base are represented by the same reference numeral 2, and the element connection terminal and the element connection terminal conductor paste layer are represented by the same reference numeral 5. is there.

(A) Green sheet preparation process (A) process is a green sheet 2 for substrates and a frame that constitute a substrate of a substrate for a light emitting device using a glass ceramic composition (LTCC composition) containing glass powder and ceramic powder. Is a step of producing a green sheet 3 for a frame that constitutes. Specifically, the base green sheet 2 and the frame green sheet 3 are composed of a glass ceramic composition containing a glass powder and a ceramic powder described below, a binder, and a plasticizer, a dispersant, a solvent, and the like as necessary. The slurry prepared by adding the material is formed into a sheet having a predetermined shape and film thickness such that the shape and film thickness after firing are within the above desired range by a doctor blade method or the like, and dried. Can be made.

For the green sheet 2 for the substrate, the sheet-like molded product obtained above is subjected to (B) paste layer forming step and subjected to lamination in step (C). About the green sheet 3 for a frame, a through hole is formed in the shape of the bottom surface 24 of the concave portion 4 (for example, a circle) by a normal method in the central portion of the sheet-like molded product obtained as described above. What was obtained is subjected to lamination in step (C).

(Preparation of glass ceramic composition and slurry)
The glass powder used in the glass ceramic composition is not necessarily limited, but the glass transition point (Tg) is preferably 550 ° C. or higher and 700 ° C. or lower. 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.

Further, it is preferable that crystals precipitate when fired at 800 ° C. or higher and 930 ° C. or lower. If crystals do not precipitate, sufficient mechanical strength may not be obtained. Furthermore, the crystallization peak temperature (Tc) measured by DTA (differential thermal analysis) is preferably 880 ° C. or less. When the crystallization peak temperature (Tc) exceeds 880 ° C., the dimensional accuracy may be lowered.

As a glass composition of such a glass powder, for example, in the following oxide conversion display, 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, and CaO is 9 mol% or more and 23 mol% or less. In addition, it is preferable that Al ₂ O ₃ is contained in an amount of 3 mol% to 8 mol% and at least one selected from K ₂ O and Na ₂ O in total of 0.5 mol% to 6 mol%. Thereby, it becomes easy to improve the flatness of the surface of the obtained base or frame.

Here, SiO ₂ becomes 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 64 mol% or less, more preferably 63 mol% or less.

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 content of B ₂ O ₃ is preferably 14 mol% or more, more preferably 15 mol% or more. Further, the content of B ₂ O ₃ is preferably 17 mol% or less, more preferably 16 mol% or less.

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. The content of Al ₂ O ₃ is preferably 7 mol% or less, more preferably 6 mol% or less.

CaO is added to increase glass stability and crystal precipitation, and to lower the glass melting temperature and glass transition point (Tg). When the content of CaO is less than 9 mol%, the glass melting temperature may be excessively high. On the other hand, when the content of CaO 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 the total content of K ₂ O and Na ₂ O is less than 0.5 mol%, the glass melting temperature and the glass transition point (Tg) may be excessively 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 other components are contained, the total content is preferably 10 mol% or less.

The glass powder is obtained by producing glass from a glass raw material by a melting method and pulverizing by a dry pulverization method or a wet pulverization method so as to have the glass composition as described above. In the case of the wet pulverization method, water is preferable as the solvent. The pulverization is performed using a pulverizer such as a roll mill, a ball mill, or a jet mill.

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. The particle size is adjusted by, for example, classification as necessary after pulverization. In addition, in this specification, a particle size means the value obtained with the particle diameter measuring apparatus by a laser diffraction scattering method.

On the other hand, as the ceramic powder, 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. Moreover, when producing the LTCC which has a diffuse reflectance used as needed in this invention, the mixture of an alumina powder and a zirconia powder is used preferably as said ceramic powder. The mixture of alumina powder and zirconia powder is preferably a mixture in which the mixing ratio of alumina powder: zirconia powder is 90:10 to 60:40 by mass ratio. The 50% particle size (D ₅₀ ) of the ceramic powder is preferably 0.5 μm or more and 4 μm or less in any of the above cases.

A glass ceramic composition is prepared by blending and mixing such glass powder and ceramic powder such that the glass powder is 30% by mass to 50% by mass and the ceramic powder is 50% by mass to 70% by mass. obtain.

A slurry is obtained by adding a binder and, if necessary, a plasticizer, a dispersant, a solvent and the like to the glass ceramic composition. As the binder, for example, polyvinyl butyral or acrylic resin is preferably used. As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate, or the like is used. As the solvent, for example, an organic solvent such as toluene, xylene, 2-propanol, 2-butanol or the like is preferably used.

(B) Paste layer forming step In the (B) step, the following (B-1) wiring conductor paste layer forming step and (B-2) metal layer paste layer are applied to the green sheet 2 for the substrate obtained above. Each paste layer is formed in the order of the forming step and (B-3) overcoat glass paste layer forming step.

(B-1) Wiring conductor paste layer forming step First, the substrate green sheet 2 is formed by using a conductor paste to form a wiring conductor paste layer (element connection terminal paste layer 5, external connection terminal paste layer 6, and A through conductor paste layer 7) is formed. Specifically, a pair of through-holes penetrating from the main surface 21 to the back surface 23 for arranging the pair of through-conductors 7 at the predetermined positions of the base green sheet 2 is formed and filled with the through-holes. Thus, the paste layer 7 for through conductors is formed. Further, the element connection terminal paste layer 5 is formed in a substantially rectangular shape so as to cover the through conductor paste layer 7 on the main surface 21, and the external connection terminal is electrically connected to the through conductor paste layer 7 on the back surface 23. A paste layer 6 is formed.

As a conductor paste used for forming a wiring conductor paste layer, for example, a metal powder mainly composed of copper, silver, gold, etc., added with a vehicle such as ethyl cellulose, and a solvent, etc., if necessary, is made into a paste. Can be used. As the metal powder, a metal powder composed of silver, a metal powder composed of silver and platinum, or a metal powder composed of silver and palladium is preferably used.

Examples of a method for forming the element connection terminal paste layer 5, the external connection terminal paste layer 6, and the through conductor paste layer 7 include a method of applying and filling the conductor paste by a screen printing method. The film thicknesses of the element connection terminal paste layer 5 and the external connection terminal paste layer 6 to be formed are adjusted so that the film thicknesses of the element connection terminals and the external connection terminals finally obtained are the above-described predetermined film thicknesses. The

(B-2) Metal layer paste layer forming step The metal layer at the predetermined position excluding the portion where the element connection terminal paste layer 5 is formed and the vicinity thereof on the main surface 21 of the green sheet 2 for the substrate. A paste layer 8 is formed. The metal layer paste layer 8 is positioned so that the outer edge of the metal layer paste layer 8 is outside the outer periphery of the bottom surface 24 of the recess 4 after firing, preferably 100 to 200 μm outside on one side, more preferably 130 to 170 μm outside. It is formed in a shape similar to the outer periphery of the bottom surface 24 of the recess 4. The film thickness of the metal layer paste layer 8 is adjusted so that the finally obtained metal layer has the predetermined film thickness.

Here, the light emitting element substrate shown in FIG. 2 differs from the light emitting element substrate shown in FIG. 1 only in the shape of the outer edge of the metal layer paste layer 8. In the light emitting element substrate shown in FIG. 2, the outer edge of the metal layer paste layer 8 has a substantially square shape similar to the shape of the main surface 21 of the base green sheet 2, and at least after firing, The total length of the entire outer periphery of the bottom surface 24 is preferably 40% or more, more preferably 60% or more so that a part of the edge straddles the outer periphery of the bottom surface 24 of the recess 4. 8 is formed to straddle. The light emitting element substrate shown in FIG. 2 can be manufactured in the same manner as the light emitting element substrate shown in FIG. 1 except for the shape when the metal layer paste layer is formed.

As the metal layer paste, it is possible to use a paste obtained by adding the above-described metal material containing silver as a main component to a vehicle such as ethyl cellulose and, if necessary, a solvent.

(B-3) Overcoat Glass Paste Layer Formation Step Next, the edge of the metal layer paste layer 8 formed on the main surface 21 of the base green sheet 2 is formed on the portion serving as the bottom surface 24 of the recess 4. An overcoat glass paste layer 9 is formed so as to cover the whole and exclude the portion where the element connection terminal paste layer 5 is formed and the vicinity thereof.

As the overcoat glass paste, a paste obtained by adding a vehicle such as ethyl cellulose to a glass powder (glass powder for an overcoat glass layer) and a solvent as required can be used. The film thickness of the overcoat glass paste layer 9 to be formed is adjusted so that the film thickness of the finally obtained overcoat glass layer 9 becomes the desired film thickness.

As the glass powder for the overcoat glass layer, any glass powder can be obtained by firing in the following (D) firing step, and its 50% particle size (D ₅₀ ) is 0.5 μm or more and 2 μm. The following is preferred. The surface roughness Ra of the overcoat glass layer 9 can be adjusted, for example, by adjusting the particle size of the glass powder for the overcoat glass layer. That is, as the glass powder for the overcoat glass layer, the surface roughness Ra can be adjusted to the above preferable range within the range of the 50% particle size (D ₅₀ ), which is sufficiently melted during firing and excellent in fluidity.

(C) Laminating Step On the green sheet 2 for the substrate on which the various paste layers are formed obtained in the step (B), the green sheet 3 for a frame body prepared in the step (A) is laminated. A sintered light-emitting element substrate 1 is obtained.

(D) Firing step After the step (C), the obtained unsintered substrate 1 for light-emitting element is degreased to remove a binder or the like as necessary, and the glass ceramic composition or the like is sintered. Firing (firing temperature: 800 to 930 ° C.) is performed.

Degreasing can be performed, for example, by holding at a temperature of 500 ° C. to 600 ° C. for 1 hour to 10 hours. When the degreasing temperature is less than 500 ° C. or the degreasing time is less than 1 hour, the binder or the like may not be sufficiently removed. On the other hand, if the degreasing temperature is about 600 ° C. and the degreasing time is about 10 hours, the binder and the like can be sufficiently removed, and if it exceeds this, productivity and the like may be lowered.

In addition, the firing can be performed by appropriately adjusting the time in a temperature range of 800 ° C. to 930 ° C. in consideration of obtaining a dense structure of the base 2 and the frame 3 and productivity. Specifically, it is preferable to hold at a temperature of 850 ° C. or higher and 900 ° C. or lower for 20 minutes or longer and 60 minutes or shorter, particularly preferably at a temperature of 860 ° C. or higher and 880 ° C. or lower. If the firing temperature is less than 800 ° C., the base 2 and the frame 3 may not be obtained as a dense structure. On the other hand, if the firing temperature exceeds 930 ° C., the substrate may be deformed and the productivity may decrease. Further, when a metal paste containing a metal powder mainly composed of silver is used as the conductor paste for the wiring conductor or the metal layer paste, when the firing temperature exceeds 880 ° C., the metal paste is excessively softened. It may become impossible to maintain the shape.

In this way, the unsintered light emitting element substrate 1 is fired to obtain the light emitting element substrate 1. After firing, the whole of the element connection terminals 5 and the external connection terminals 6 are covered as necessary. The conductive protective layers used for conductor protection in the substrate for a light emitting element, such as nickel plating, chrome plating, silver plating, nickel / silver plating, gold plating, nickel / gold plating, etc., described above can be provided. Of these, nickel / gold plating is preferably used. For example, the nickel plating layer can be formed by electrolytic plating using a nickel sulfamate bath or the like, and the gold plating layer using a potassium gold cyanide bath or the like.

As mentioned above, although the manufacturing method was demonstrated about the example of embodiment of the board | substrate for light emitting elements of this invention, the green sheet 2 for base | substrates, the green sheet 3 for frames, etc. do not necessarily need to consist of a single green sheet. Alternatively, a laminate of a plurality of green sheets may be used. Further, the order of forming each part can be changed as appropriate as long as the light emitting element substrate can be manufactured.

In addition, the light emitting element substrate of the present invention is usually manufactured as a connection substrate or a large-sized substrate so that a large number of light emitting element substrates can be manufactured at a time, and a process for dividing the substrate is performed to manufacture individual light emitting element substrates. It may be produced by a method. In that case, as long as the timing of division is after the firing, it may be before the light emitting element is mounted, or after the light emitting element is mounted, before the solder fixing and mounting to the printed wiring board or the like.

The substrate for a light emitting element of the present invention using LTCC as an inorganic insulating material, the manufacturing method thereof, and the light emitting device have been described above. For the light emitting element of the present invention when alumina ceramic is used as the inorganic insulating material, A configuration and a manufacturing method of the embodiment of the substrate will be briefly described.

For example, when a light-emitting element substrate similar to the light-emitting element substrate 1 using LTCC shown in FIG. 1 is manufactured using alumina ceramics, in order to reduce warpage of the entire light-emitting element substrate, as already described. A part of the metal layer to be provided is disposed between the base and the frame. For this reason, since co-firing with alumina ceramics is essential, one made of a refractory metal containing at least one refractory metal selected from the group consisting of tungsten and molybdenum as a main component is selected. Here, the metal layer composed of a refractory metal containing as a main component at least one of the refractory metals described above includes such a refractory metal (herein, the refractory metal includes an alloy of the refractory metal described above), It refers to a metal layer containing 90% or more.

Here, in the light emitting element substrate 1 shown in FIG. 1, the metal layer 8 is made of a metal material mainly composed of silver that can be fired at a low temperature, and functions as a reflective layer. In the case of the conventional light emitting element substrate, the metal layer made of tungsten, molybdenum, or the like used in combination with the metal material layer mainly composed of silver does not have sufficient light reflectivity. Usually, after firing, it is designed to serve as a base layer for forming a reflective layer using a metal having good reflectivity such as silver.

Therefore, as a structure of the light emitting element substrate using alumina ceramics, for example, a reflective layer such as silver is formed between the overcoat glass layer 9 and the metal layer 8 as compared with the light emitting element substrate 1 shown in FIG. In addition, the constituent material of each member, specifically, the inorganic insulating material, the metal material, etc. can be the same as the configuration of the light emitting element substrate 1 shown in FIG. . When a reflective layer (silver reflective layer) using a metal having good reflectivity such as silver is formed on the upper layer of a metal layer made of tungsten, molybdenum or the like, the silver reflective layer is an outer periphery of the bottom surface 24 of the recess 4. It is not formed between the base 2 and the frame body 3 across the frame. The overcoat glass layer 9 is formed as necessary, and may not be formed depending on the design of the light emitting element substrate.

Moreover, the light emitting element substrate using such alumina ceramics can be manufactured as follows, for example.
(A ′) Green sheet production step In place of the glass ceramic composition (LTCC composition) containing glass powder and ceramic powder, an alumina ceramic composition containing alumina as a main component is used. Through the same process as the sheet manufacturing process, the base green sheet 2 and the frame green sheet 3 are obtained. In addition, as a composition for alumina ceramics which has an alumina as a main component, the composition for alumina ceramics normally used when producing an alumina ceramic can be used without a restriction | limiting in particular.

(B ′) Wiring conductor paste layer and metal layer paste layer forming step In the case of a substrate for a light emitting device using alumina ceramics, a wiring conductor layer and a metal layer for reducing warping (functions as a base layer of a reflective layer) As described above, a metal material mainly composed of a refractory metal such as tungsten or molybdenum is used as the metal material constituting the metal layer. That is, in place of the silver-based conductor paste and metal layer paste used above, a highly heat-resistant wiring conductor paste and metal layer paste mainly composed of a refractory metal such as tungsten or molybdenum And (B) the same process as the (B) wiring conductor paste layer and metal layer paste layer forming process. In this manner, the wiring conductor paste layer and the metal layer paste layer are formed on the base green sheet 2 obtained in the step (A ′).

(C ′) Lamination Step An unsintered substrate 1 for a light emitting element is obtained through the same step as the above (C) lamination.

(D ′) Firing Step After the step (C ′), the obtained unsintered substrate 1 for light-emitting element is degreased to remove a binder or the like as necessary, and a composition for alumina ceramics or the like is obtained. Firing (firing temperature: 1400 to 1700 ° C.) is performed for sintering. For example, the degreasing is preferably performed under a condition of holding at a temperature of 200 ° C. to 500 ° C. for about 1 hour to 10 hours. For example, the firing is preferably performed at a temperature of 1400 ° C. or higher and 1700 ° C. or lower for several hours. However, in order not to oxidize the conductor during heating, particularly during firing, heating must be performed in a reducing atmosphere (for example, a hydrogen atmosphere), in an inert gas atmosphere, or in a vacuum, while maintaining a non-oxidizing atmosphere. Don't be.

In this way, the unsintered light emitting element substrate 1 is baked to obtain the light emitting element substrate 1, and silver or the like having good reflectivity is applied to the surface of the metal layer 8 formed as the base layer of the reflective layer. The reflective layer as a main component is formed by combining methods such as screen printing, sputter deposition, and ink jet coating. Furthermore, an overcoat glass layer 9 similar to the light emitting element substrate 1 using, for example, the LTCC is formed as necessary so as to cover the entire reflective layer. Also, the conductive protective layer similar to that of the light emitting element substrate 1 using the LTCC can be disposed on the element connection terminals 5 and the external connection terminals 6 as needed so as to cover the whole. .

Examples of the present invention will be described below. The present invention is not limited to these examples.
[Example 1]
A light emitting element substrate having a structure similar to that of the light emitting element substrate shown in FIG. 1 was manufactured by the method described below. In addition, the same code | symbol used for a member before and behind baking was used similarly to the above.

First, the base green sheet 2 and the frame green sheet 3 for manufacturing the base 2 and the frame 3 of the light emitting element substrate 1 were prepared. Each green sheet, the following terms of oxide, SiO ₂ is _60.4mol%, B 2 _{O 3} is 15.6mol%, _Al 2 _{O 3} is 6 mol%, CaO is 15 mol%, _{K 2} O is 1 mol%, Na _The raw materials were blended and mixed so that the glass had a composition of ₂ O in 2 mol%. 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 40 hours to produce a glass powder. In addition, ethyl alcohol was used as a solvent for pulverization.

35% by mass of this glass powder, 40% by mass of alumina powder (manufactured by Showa Denko KK, trade name: AL-45H), and zirconia powder (manufactured by Daiichi Rare Element Chemical Industries, trade name: HSY-3F-J) A glass ceramic composition was produced by blending and mixing so as to be 25% by mass. 50 g of this glass ceramic composition, 15 g of an organic solvent (mixed with toluene, xylene, 2-propanol, 2-butanol in a mass ratio of 4: 2: 2: 1), a plasticizer (di-2-ethylhexyl phthalate) 2.5 g of polyvinyl butyral (trade name: PVK # 3000K, manufactured by Denka Co., Ltd.) as a binder, 5 g, and 0.5 g of a dispersant (trade name: BYK180, manufactured by Big Chemie) were blended and mixed to prepare a slurry. .

The slurry is applied on a PET film by a doctor blade method, and dried green sheets are laminated to form a substantially flat plate-like green sheet 2 having a thickness of 0.5 mm after firing. Is the same as the green sheet 2 for the substrate, and the frame green sheet 3 having a substantially circular shape with a diameter of 4.2 mm after firing and a frame height of 0.5 mm was manufactured. In this embodiment, the light-emitting element substrate 1 is manufactured as a multi-piece connecting substrate, and is divided into pieces after firing, which will be described later, for a substantially square light-emitting element having an outer size of 5 mm × 5 mm. A substrate 1 was obtained. The following description explains one division which becomes one light-emitting element substrate 1 after the division among the multi-piece connection substrates.

On the other hand, conductive powder (silver powder, manufactured by Daiken Chemical Industry Co., Ltd., trade name: S550) and ethyl cellulose as a vehicle are blended at a mass ratio of 85:15, and used as a solvent so that the solid content is 85% by mass. After being dispersed in α-terpineol, kneading was conducted for 1 hour in a porcelain mortar, and further three times of dispersion with a three roll to produce a wiring conductor paste.

The metal layer paste is prepared by mixing silver powder (manufactured by Daiken Chemical Co., Ltd., trade name: S400-2) and ethyl cellulose as a vehicle in a mass ratio of 90:10, and a solid content of 87% by mass. Then, it was dispersed in α-terpineol as a solvent so as to be kneaded for 1 hour in a porcelain mortar, and further dispersed three times with three rolls.

A through hole having a diameter of 0.3 mm is formed in a portion corresponding to the pair of through conductors 7 of the green sheet 2 for the substrate by using a punching machine, and the wiring conductor paste obtained above is filled by screen printing. A through conductor paste layer 7 was formed, and a pair of external connection terminal paste layers 6 was formed on the back surface 23. Further, a pair of element connection terminal paste layers 5 are formed in a substantially rectangular shape on the main surface 21 of the base green sheet 2 so as to cover the through conductor paste layer 7 by a screen printing method. A green sheet 2 for a substrate with a substrate was obtained.

Next, the center is the same as the center of the bottom surface 24 of the recess 4 so as to exclude the range of 150 μm from the edge of the element connection terminal paste layer 5 on the main surface 21 of the base green sheet 2. A metal layer paste layer 8 was formed by screen printing the metal layer paste obtained above in a circular range having a diameter of 4.5 mm after firing. The film thickness of the metal layer paste layer 8 was adjusted so that the finally obtained metal layer had a film thickness of 10 μm.

Further, the element connection terminal paste layer of the metal layer paste layer 8 is removed from the edge of the element connection terminal paste layer 5 on the main surface 21 of the base green sheet 2 so as to exclude the range of 100 μm. The following overcoat glass paste is screen-printed in a circular area including the peripheral edge of 5 and the formed area is the same as the bottom surface 24 of the recess 4 (that is, the diameter becomes 4.2 mm after firing). Thus, an overcoat glass paste layer 9 was formed. The film thickness of the overcoat glass paste layer 9 was adjusted so that the film thickness of the finally obtained overcoat glass layer was 30 μm. Further, the surface roughness Ra of the overcoat glass layer 9 after firing was 0.006 μm as measured by Surfcom 1400D manufactured by Tokyo Seimitsu Co., Ltd.

Here, the glass powder for the overcoat glass layer used for the preparation of the overcoat glass paste was produced as follows. First, in terms of the following oxides, the raw materials are blended and mixed so that SiO ₂ is 81.6 mol%, B ₂ O ₃ is 16.6 mol%, and K ₂ O is 1.8 mol%. 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 8 to 60 hours to obtain a glass powder for an overcoat glass layer.

In this porcelain mortar, the glass powder for the overcoat glass layer was blended so as to be 60% by mass and the resin component (containing ethyl cellulose and α-terpineol at a mass ratio of 85:15) to 40% by mass. Were kneaded for 1 hour and further dispersed three times with three rolls to prepare an overcoat glass paste.

The green sheet 3 for a frame body obtained above was laminated on the main surface 21 of the green sheet 2 for a substrate with various paste layers obtained above to obtain an unsintered multi-piece connection substrate. After putting the cut line for dividing such that each section of the unsintered light emitting element substrate 1 has an outer size of 5 mm × 5 mm after firing, in the unfired multi-piece connection substrate obtained above, 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 a multi-piece connected substrate. The obtained multi-piece connection substrate was divided along the cut line to manufacture the light emitting device substrate 1.

In the obtained light emitting element substrate 1, the recess 4 having the side wall 25 as the inner wall surface of the frame 3 and the bottom surface 24 as a part of the substrate main surface 21 is a circle having a diameter of 4.2 mm with respect to the shape of the bottom surface 24. It was a shape. In addition, the metal layer 8 was formed so that 150 μm entered between the base 2 and the frame 3 almost evenly so as to straddle the entire length (100%) of the outer periphery of the bottom surface 24. The side surface 25 of the recess 4 is formed substantially perpendicular to the bottom surface 24, and the haze value on the inner wall surface of the frame body is 100% when measured with a haze meter (NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.). .

When the warpage of the obtained light emitting element substrate 1 was measured with a surfcom 1400D manufactured by Tokyo Seimitsu Co., Ltd., the heights of the lowest position (both ends) and the highest position (substantially central portion) of the back surface 23 of the light emitting element substrate 1 The difference was 10 μm. Further, when the bonding strength between the base 2 and the frame 3 was measured with a multi-bond tester SS-30WD (manufactured by Seishin Shoji Co., Ltd.) for the obtained light emitting device substrate 1,> 40 N / mm ² (base 2 and frame 3). 3) No peeling at the interface. The results are shown in Table 1.

[Examples 2 to 4]
A light-emitting element substrate 1 that was the same as the light-emitting element substrate in Example 1 was prepared except that it had a substantially square metal layer 8 similar to the light-emitting element substrate shown in FIG.
In Example 2, the outer shape of the portion where the metal layer 8 was formed was a substantially square shape that became 3.5 mm square after firing. Moreover, in the light emitting element use substrate 1 of Example 2, the rate that the metal layer 8 straddled the outer periphery of the bottom surface 24 of the recess 4 was 43% with respect to the entire outer peripheral length. In the same manner as in Example 1, the warpage of the light emitting element substrate 1 and the bonding strength between the base 2 and the frame 3 were measured. The results are shown in Table 1.

Example 2 Light-emitting element substrates 1 of Example 3 and Example 4 were produced in exactly the same manner as Example 2 except that the size of the metal layer 8 was changed to the size shown in Table 1. In Example 3 and Example 4, the rate at which the metal layer 8 straddled the outer periphery of the bottom surface 24 of the recess 4 was 53% and 70%, respectively, with respect to the total outer peripheral length. For these light emitting element substrates 1, the warpage of the light emitting element substrate 1 and the bonding strength between the base 2 and the frame 3 were measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative example]
In Example 1 above, except that the metal layer 8 was formed in a circular shape with a diameter of 4.2 mm exactly the same as the bottom surface 24 of the recess 4, and the metal layer 8 was formed so as not to straddle the outer periphery of the bottom surface 24 at all. A light emitting device substrate 1 of a comparative example was produced in exactly the same manner as in Example 1. For the obtained light emitting element substrate 1, the warpage of the light emitting element substrate 1 and the bonding strength between the base 2 and the frame 3 were measured in the same manner as in Example 1. The results are shown in Table 1.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to reduce the ratio of curvature of board | substrate itself in the board | substrate for light emitting elements which has a recessed part and mounts a light emitting element in the bottom face. The light emitting device according to the present invention has the light emitting element substrate according to the present invention in which the warpage is reduced as described above, thereby reducing the positional deviation and inclination of the light emitting element, the light directivity being different from the design, and the bonding wire. This is a light-emitting device in which problems such as occurrence of disconnection due to misalignment are suppressed. In addition, when the light emitting device is further mounted on a printed wiring board or the like using solder, problems such as disconnection and deterioration of heat dissipation, which are caused by the warpage of the board, can be reduced. Such a light-emitting device of the present invention can be suitably used as a backlight for a liquid crystal display of a mobile phone, a personal computer, or a flat television, for example, illumination for automobiles or decoration, general illumination, and other light sources.
The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2010-241077 filed on Oct. 27, 2010 are incorporated herein as the disclosure of the present invention. .

DESCRIPTION OF SYMBOLS 1 ... Light emitting element substrate, 2 ... Base | substrate (green sheet for board | substrates), 3 ... Frame body (green sheet for frame bodies), 4 ... Recessed part, 5 ... Element connection terminal (element connection terminal paste layer), 6 ... External Connection terminal (external connection terminal paste layer), 7 ... through conductor (through conductor paste layer), 8 ... metal layer (metal layer paste layer), 9 ... overcoat glass layer (overcoat glass paste layer), 10 DESCRIPTION OF SYMBOLS ... Light-emitting device, 11 ... Light emitting element, 12 ... Bonding wire, 13 ... Sealing layer 21 ... Main surface of base | substrate, 22 ... Light-emitting-element mounting part, 23 ... Back surface of base | substrate, 24 ... Bottom face of a recessed part, 25 ... Side surface of a recessed part

Claims

A plate-like substrate having a flat main surface made of the first inorganic insulating material; and a frame made of a second inorganic insulating material joined to the upper main surface of the substrate, the upper main surface of the substrate A light emitting element substrate having a light emitting element mounting portion on a bottom surface of a recess formed with a part of the bottom surface as an inner wall surface of the frame body,
A metal layer is provided on the bottom surface of the recess so that at least part of the metal layer is disposed between the frame body and the base so as to straddle the outer periphery of the bottom of the recess and does not reach the outer edge of the base. Light emitting element substrate.
The light emitting element substrate according to claim 1, wherein the metal layer is disposed between the frame body and the base so as to straddle the outer periphery of the bottom surface of the recess in the entire periphery.
2. The light emitting element substrate according to claim 1, wherein a total outer peripheral length of a portion where the metal layer is disposed across the outer periphery of the concave bottom surface is 40% or more with respect to a total outer peripheral length of the concave bottom surface. .
The light emitting element substrate according to any one of claims 1 to 3, wherein a distance (L) from an outer periphery of the bottom surface of the recess to an edge of the metal layer between the frame and the base is 100 to 200 µm. .
The light emitting element substrate according to any one of claims 1 to 4, wherein the metal layer is a reflective layer or a base layer for forming the reflective layer.
The first inorganic insulating material and the second inorganic insulating material are both sintered bodies of a glass ceramic composition containing glass powder and ceramic powder, and the metal constituting the metal layer is a metal mainly composed of silver. The light emitting device substrate according to any one of claims 1 to 5, wherein:
The first inorganic insulating material and the second inorganic insulating material are both sintered bodies of an alumina ceramic composition, and the metal constituting the metal layer is mainly composed of at least one selected from the group consisting of tungsten and molybdenum. The light-emitting element substrate according to claim 1, wherein the light-emitting element substrate is a metal.
The light emitting element substrate according to claim 7, wherein a metal reflective layer mainly composed of silver is formed on a metal layer mainly composed of at least one selected from the group consisting of tungsten and molybdenum.
A light emitting device substrate according to any one of claims 1 to 8,
And a light emitting device mounted on the light emitting device substrate.