JP2012248593A - Light-emitting element substrate and light-emitting device - Google Patents

Abstract

The present invention provides a ceramic light emitting device substrate having a recess in which the amount of warpage of the entire substrate is reduced, and a light emitting device having high reliability in light directivity and electrical connection using the substrate.
A base having a flat main surface made of a first inorganic insulating material and a frame made of a second inorganic insulating material joined to an upper main surface of the base, the base A substrate for a light emitting element having a light emitting element mounting portion on a bottom surface of a recess formed with a part of the upper main surface as a bottom surface and an inner wall surface of the frame as a side surface, and passes through a center point of the upper main surface. A substrate for a light-emitting element, characterized in that a warpage amount, which is a difference in height between the highest portion and the lowest portion of the upper main surface in the cross section, measured using a cross section of the substrate orthogonal to the main surface is 30 μm or less. .
[Selection] Figure 2

Description

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

  2. Description of the Related Art 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. As a typical example of this wiring substrate, a concave portion for accommodating a light emitting element is formed on an insulating substrate made of alumina ceramic, and the surface and the inside of the insulating substrate are made of refractory metal powder such as tungsten or molybdenum. There is a wiring board having a configuration in which a plurality of wiring conductor layers are arranged and electrically connected to a light emitting element housed in a recess.

  Further, as an insulating substrate of such a wiring substrate for a light-emitting element, low temperature firing, low dielectric constant, and high electrical conductivity copper and silver wiring are possible, so that glass ceramics containing glass powder and ceramic powder are included. A substrate composed of a low temperature co-fired ceramics (hereinafter referred to as LTCC), which is a sintered body of the composition, has been proposed.

  A ceramic wiring board such as LTCC having the above-mentioned concave portion is usually fired a laminate in which at least a flat green sheet constituting the bottom surface of the concave portion and a green sheet having a through-opening portion constituting the wall portion of the concave portion are laminated. It is manufactured by doing. The wiring conductor layer is formed as an unsintered layer on the surface or inside of each green sheet before the lamination of the green sheets, and is fired at the same time as the green sheets are fired.

  In the ceramic wiring board having the recesses manufactured in this way, there is a problem that the central portion of the flat substrate constituting the bottom surface of the recess is warped due to stress concentration caused by firing shrinkage in the manufacturing process. Was. When such a warped wiring board is used, when the light emitting element is mounted, the mounting position of the light emitting element and the positional deviation of the bonding wire occur, resulting in disconnection, and the result that the light emitting element is mounted tilted. There were problems such as affecting the directivity of light. Also, when mounting this wiring board on a printed wiring board or the like using solder, the warping of the center of the back surface of the wiring board causes warpage between the wiring conductor layer on the back surface, which is an external connection electrode, and the solder. There was a problem that a gap was formed, causing disconnection and preventing heat dissipation.

  In order to solve the problem of warping of the ceramic wiring board having the concave portion, for example, in Patent Document 1, a ceramic member having a flat ceramic substrate constituting the concave bottom surface and a through opening constituting the wall portion of the concave portion A method is adopted in which a layer made of a ceramic material having a different shrinkage from the ceramic material constituting the other part is formed near the interface between the two.

  In Patent Document 2 and Patent Document 3, a plurality of green sheets including a thin green sheet having a through-opening portion 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, a dent is further formed while suppressing the warping of the central portion (bottom surface of the concave portion), and a conductor layer is formed on the entire surface of the flat ceramic substrate or partially so as to fill the dent portion. Thus, the bottom of the recess is flattened.

  Furthermore, in addition to the external connection electrode pattern on the back side of the wiring board, a dummy electrode pattern that is not soldered to the printed wiring board or the like, or a reflective film such as silver formed on the top surface of the wiring board Attempts have also been made to suppress warping of a flat substrate by adjusting the shape. However, in any of these methods, the warp of the ceramic wiring board having the recesses could not be sufficiently suppressed.

JP 2007-281108 A JP 2010-186880 A JP 2010-186881 A

  The present invention has been made in order to solve the problem of warping of the substrate for a ceramic 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. An object of the present invention is to provide a light-emitting device that is highly reliable in terms of directivity of light and electrical connection. Note that in this specification, the light emitting element substrate may be referred to as an element substrate.

The element substrate of the present invention has 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 joined to the upper main surface of the substrate. An element substrate having a light emitting element mounting portion on a bottom surface of a recess formed with a part of an upper main surface of the base as a bottom surface and an inner wall surface of the frame body as a side surface, the center point of the upper main surface being a center point A warpage amount, which is a difference in height between the highest portion and the lowest portion of the upper main surface in the cross section, measured using a cross section of the substrate perpendicular to the main surface passing therethrough is 30 μm or less.
In the element substrate of the present invention, the amount of warpage is preferably 25 μm or less.

Further, in the element substrate of the present invention, the base body and the frame body are made of a fired body of a laminated body in which a plurality of ceramic green sheets are laminated, and at least the number of green sheets to be the base body is two or more, It is preferable that the area shrinkage rate during firing of the green sheet constituting the lowermost layer of the body is smaller than the area shrinkage rate during firing of the green sheet constituting the layer other than the lowermost layer.
In the element substrate of the present invention, the area of the main surface of the substrate is 16 to 25 mm ² , the area of the bottom surface of the recess is 50 to 70% of the area of the main surface of the substrate, and the total thickness of the substrate and the frame is 0.00. 6 to 1.2 mm, and the thickness of the substrate is 40 to 60% of the total thickness, and the green sheet constituting the lowermost layer has a thickness after firing of 10 to 10% of the total thickness. It is preferably 20%.

In the element substrate of the present invention, the size and the thickness condition after firing of the green sheet constituting the lowermost layer are the above cases, and the area shrinkage ratio is defined by the length of the main surface in the vertical and horizontal directions. When the area reduction rate of the main surface when a flat green sheet having a thickness of 40 mm and a thickness of 1.0 mm is used as a fired body, the area shrinkage rate of the green sheet constituting the bottom layer of the laminate is It is preferably 0.2 to 1.0% smaller than the area shrinkage rate of the green sheet other than the lowermost layer.
In the element substrate of the present invention, both the first inorganic insulating material and the second inorganic insulating material are preferably a sintered body of a glass ceramic composition containing glass powder and ceramic powder.
The light emitting device of the present invention includes the element substrate of the present invention and a light emitting element mounted on the mounting portion of the element substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the board | substrate for ceramics light emitting elements which has a recessed part can provide the element board | substrate which reduced the curvature amount of the whole board | substrate. Further, according to the present invention, by mounting a light emitting element on such an element substrate, a light emitting device with high reliability in light directivity, electrical connection, and the like can be obtained.

It is a figure which shows the curvature amount of the board | substrate for light emitting elements. It is the top view and sectional drawing which show an example of embodiment of the board | substrate for light emitting elements of this invention. It is sectional drawing which shows an example of the light-emitting device of this invention using the board | substrate for light emitting elements shown in FIG.

Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is limited to the following description and is not interpreted.
The element substrate of the present invention has 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 joined to the upper main surface of the substrate. An element substrate having a light emitting element mounting portion 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, the center point of the upper main surface The amount of warpage, which is a difference in height between the highest portion and the lowest portion of the upper main surface in the cross section, measured using a cross section of the base body orthogonal to the main surface passing through is 30 μm or less. The amount of warpage is preferably 25 μm or less, and more preferably 10 μm or less.

  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 on the visual level unless otherwise specified.

  First, the “warping amount” of the element substrate will be described with reference to FIG. FIG. 1A shows a plan view of the element substrate as viewed from above. Specifically, the amount of warpage will be described by taking the element substrate 1 having the base body 2 and the frame 3 as an example, and the cross section of the base body 2 orthogonal to the main surface passing through the center point C of the upper main surface of the base body 2; For example, the height difference H between the highest part and the lowest part of the upper main surface of the substrate 2 measured using the cross section shown in FIG. The cross section of the base 2 for measuring the amount of warpage may be any cross section as long as it is a cross section orthogonal to the main surface passing through the center point C. For example, when the upper main surface of the base 2 is rectangular, the main surface However, a cross section including a straight line passing through the center point C and parallel to the long side as shown in FIG. 1B is preferably used.

  The amount of warpage is measured by, for example, cutting the element substrate with a dicing machine or the like so that a cross section orthogonal to the main surface passing through the center point of the upper main surface of the base is obtained, and measuring the obtained cross section with a length measuring microscope. Can be calculated. The “warpage amount” used in this specification refers to the warpage amount measured by the above method unless otherwise specified. In addition, about the measurement of curvature amount, you may use the method of measuring nondestructively, without cutting | disconnecting an element substrate as needed. A non-destructive method for measuring the amount of warping is a method using a three-dimensional measuring instrument using a laser displacement meter. For example, the surface shape of the bottom surface of the concave portion of the element substrate using a high-precision shape measuring system KS1100 manufactured by Keyence, etc. It is possible to measure the amount of warping.

  According to the present invention, in an element substrate made of an inorganic insulating material having a recess and having a light emitting element mounted on its bottom surface, the warp amount is 30 μm or less, preferably 25 μm or less, more preferably 10 μm or less. The bottom surface is sufficiently flattened, so that the positional deviation and inclination of the light emitting element when the light emitting element is mounted can be reduced, and 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 this 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 order to make the amount of warpage within the scope of the present invention, for example, in the element substrate of the present invention, the base body and the frame body are a fired body of a laminate in which a plurality of ceramic green sheets are laminated as a whole, The green sheet constituting the substrate is configured so that the number of laminated green sheets is 2 or more, and the area shrinkage ratio during the firing of the green sheet constituting the lowermost layer of the laminate is the green sheet constituting other than the lowermost layer What is necessary is just to comprise so that it may become small compared with the area shrinkage rate at the time of baking. A specific method will be described later.

  Here, the area shrinkage rate in this specification is the area reduction rate calculated by (Sb−Sa) / Sb × 100 from the area Sb before firing and the area Sa after firing on the main surface of the ceramic green sheet. Say. As the area shrinkage rate, the length and width of the main surface are 40 mm each, and the ceramic green sheet having a thickness of 1.0 mm is used to produce a fired body of the ceramic green sheet laminate, that is, It is preferable to use a value measured and calculated when firing under the same firing conditions as firing when the element substrate is manufactured. In addition, it does not restrict | limit especially as a means to measure the vertical and horizontal length of a ceramic green sheet and the obtained sintered body, For example, it can measure with a digital caliper. Hereinafter, the area shrinkage ratio of the ceramic green sheet measured as described above at this size is represented by “D” as necessary.

  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 (LTCC) of a glass ceramic composition containing a glass sintered body and glass powder and ceramic powder. 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, from the viewpoints of ease of manufacture, easy processability, economy, and the like, when the substrate and the frame are further composed of a plurality of ceramic green sheets, LTCC is preferred because it is easy to make a difference in the area shrinkage rate between the green sheets. In addition, as long as the first and second inorganic insulating materials are made of the same kind of ceramic, for example, a glass ceramic composition capable of obtaining a high bending strength is applied to the base body in LTCC, and the diffused reflectivity is emphasized in the frame. The raw material composition of the ceramics may be different depending on the required characteristics of the substrate and the frame so that the glass ceramic composition is applied.

As an example of the embodiment of the element substrate of the present invention, an 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 will be described below.
FIG. 2A is a plan view showing an example of an element substrate 1 for mounting one light emitting element according to an embodiment of the present invention, and FIG.

  The element substrate 1 has a substantially flat base 2 that is mainly composed of the element substrate 1 and has a substantially square shape when viewed from above. The base body 2 has an upper surface on which the light emitting element is mounted as a main surface 21 as an element substrate, 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 element substrate 1 further has a frame body 3 joined to the peripheral edge portion of the main surface 21 of the base body so as to constitute a recess 4 having a substantially circular portion at the center of the main surface 21 of the base body 2 as a bottom surface 24. In addition, the side surface of the recess 4 is constituted by the inner wall surface of the frame 3. In the element substrate 1, a substantially central portion of the concave bottom surface 24 is a mounting portion 22 on which a light emitting element is mounted.

  Here, the side surface of the recess 4 is provided so as to be substantially perpendicular to the bottom surface 24 thereof. That is, the frame body 3 is formed with the same opening at the top and bottom, and is joined to the peripheral edge portion of the main surface 21 of the base 2. The shape of the frame 3 is not limited to this, and the frame 3 may be formed such that the upper opening is large and the lower opening is small, and the side surface is tapered. When such a frame 3 is used, a concave portion 4 whose side surface is inclined with respect to the bottom surface 24 is formed.

  Specific numerical values of the distance between the side surface 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, For example, the distance at which the light emitted from the light emitting element is most efficiently emitted in the light extraction direction, depending on the type of phosphor used for inclusion in a sealing layer, which will be described later, the content thereof, conversion efficiency, and the like. May be used as an index.

  The height of the side surface of the recess 4, that is, the distance from the bottom surface 24 of the recess 4 to the highest position of the frame body 3 (the height of the frame body 3) The height is not particularly limited as long as the height can be sufficiently reflected. 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 the sealing material containing the phosphor for the purpose, it is preferable that the height is 100 to 500 μm higher than the height of the highest portion 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.

  The base 2 and the frame 3 are both composed of a sintered body (LTCC) of a glass ceramic composition containing glass powder and ceramic powder. Specifically, a sintered body of the glass ceramic composition is formed by firing a green sheet for LTCC produced using a slurry containing a glass ceramic composition for LTCC, a binder resin, a solvent, and the like. .

  Here, the base body 2 and the frame body 3 are formed by laminating two LTCC green sheets for the base body 2, and the frame body 3 is composed of a single-layer LTCC green sheet. It is comprised by the sintered body of the laminated body which laminated | stacked. In the laminate, the lower green sheet constituting the lower layer of the base body is obtained as compared with the upper green sheet of the base body laminated thereon and the frame green sheet laminated thereon. The area shrinkage rate at the time of firing is configured to be small. In addition, it is preferable that the area shrinkage rate at the time of baking of a base body upper side green sheet and a frame body green sheet is equivalent.

Hereinafter, the comparison of the area shrinkage rate is performed between the lower green sheet of the substrate (hereinafter referred to as “lower green sheet”) and the upper green sheet of the substrate (hereinafter referred to as “upper green sheet”). Unless otherwise indicated, the comparison is based on the premise that the area shrinkage rate during firing of the upper green sheet and the frame green sheet is equal.
In FIG. 2 (b), portions where the lower green sheet and the upper green sheet are fired are shown as a base lower layer portion 2b and a base upper layer portion 2a, respectively.

The ratio of the thickness of the base layer 2b in the thickness of the base 2 or the thickness of the element substrate 1 includes the shape and size of the element substrate 1, the height of the frame, and the shape of the bottom of the recess. It is adjusted as appropriate depending on the size and the like.
For example, in the element substrate 1, the area of the main surface 21 of the base 2 is 16 to 25 mm ² , the area of the bottom surface 24 of the recess 4 is 50 to 70% of the area of the main surface 21 of the base 2, and the thickness of the base 2 The total thickness T (T = t2 + t3) of t2 and the thickness 3 of the frame 3, that is, the thickness T of the element substrate 1 is 0.6 to 1.2 mm, and the thickness t2 of the base 2 is equal to that of the element substrate 1. When the thickness T is 40 to 60%, the thickness of the lower green sheet after firing, that is, the thickness t2b of the base lower layer portion 2b is 10 to 20% of the thickness T of the element substrate 1. preferable.

  Further, when the size of the element substrate 1 and the thickness t2b of the base lower layer portion 2b with respect to the thickness T of the element substrate 1 are in the above conditions, the difference in area shrinkage between the lower green sheet and the upper green sheet is as follows. When the area shrinkage ratio D measured using a ceramic green sheet having a vertical and horizontal length of 40 mm each and a thickness of 1.0 mm is used, the area shrinkage ratio of the lower green sheet is defined as Db. It is preferable that Da-Db when the area shrinkage ratio Da of the sheet is in the range of 0.2 to 1.0%.

  If the Da-Db is less than 0.2%, the warpage amount of the element substrate 1 may not be suppressed to be within 30 μm, which is the range of the present invention. There is a possibility that the interface between the upper green sheet and the upper green sheet may peel off.

  More specifically, when the size of the element substrate 1 is in the above range and the thickness t2b of the base lower layer portion 2b with respect to the thickness T of the element substrate 1 is 10%, the lower green sheet and the upper green sheet The difference in area shrinkage rate, Da-Db, is preferably in the range of 0.4 to 1.0% from the viewpoint that peeling between the green sheet layers can be sufficiently prevented while keeping the warpage amount within 30 μm. The difference in area shrinkage rate is more preferably 0.4 to 0.8%, and the warping amount can be suppressed to 10 μm or less within this range.

  Further, when the size of the element substrate 1 is in the above range and the thickness t2b of the base lower layer portion 2b with respect to the thickness T of the element substrate 1 is 20%, the area shrinkage ratio of the lower green sheet and the upper green sheet is reduced. The difference, Da-Db, is preferably in the range of 0.2 to 0.5% from the viewpoint that peeling between the green sheet layers can be sufficiently prevented while keeping the warpage amount within 30 μm. The difference in the area shrinkage rate is more preferably 0.3 to 0.4%, and the warpage amount can be suppressed to 10 μm or less within this range.

  As a method of adjusting the area shrinkage rate in the lower green sheet and the upper green sheet constituting the base body 2 as a fired body, the composition of a glass ceramic composition for LTCC, which will be described later, is adjusted. Adjusting the composition of the slurry containing the glass ceramic composition and binder resin, solvent, etc. used in the process, adjusting the molding conditions for molding the slurry into a green sheet, and the like.

  Among the methods for adjusting the area shrinkage rate, when the method of adjusting the composition of the glass ceramic composition for LTCC is used, the LTCC constituting the base 2 is different in the base layer lower part 2b and the base upper layer part 2a. However, when adjusting the slurry and the green sheet forming conditions, the base lower layer 2b and the base upper layer 2a are made of the same LTCC.

  With respect to the LTCC constituting the base 2, any of the LTCCs constituting the base lower layer 2 b and the base upper layer 2 a has, for example, bending strength from the viewpoint of suppressing damage or the like when the light emitting element is mounted and thereafter used. LTCC having a Mn of 250 MPa or more is preferable. The LTCC that constitutes the frame 3 is preferably the same as the material that constitutes the substrate 2 in consideration of improvement in adhesion to the substrate 2 and reduction in the amount of warpage.

  Moreover, according to the required characteristic of a light-emitting device, you may use the LTCC which has diffuse reflectivity as said LTCC. The LTCC having diffuse reflectivity is not particularly limited as long as the light extraction efficiency can be improved in a light emitting device using the LTCC as a substrate material. 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.

  In addition, the raw material composition of the sintered body of the glass-ceramics composition containing the glass powder and ceramics powder which comprise such a base | substrate 2 and the frame 3, Green which contains this glass-ceramics composition, binder resin, a solvent, etc. The adjustment of the slurry for forming the sheet, the forming condition of the green sheet, the sintering condition, etc. are as described later.

  In such an element substrate 1, a pair of element connection terminals 5 electrically connected to a pair of electrodes included in the light emitting element are provided on the bottom surface 24 of the recess 4 that occupies a part of the main surface 21 of the base 2. The light emitting element mounting portion 22 is provided so as to face both sides of the mounting portion 22. One end of the pair of element connection terminals 5 extends in the peripheral direction of the bottom surface 24 of the recess 4, and the frame body 3 is disposed so as to cover the upper end. The planar shape and arrangement position of the element connection terminal 5 are not limited to those illustrated.

  The film thickness of the element connection terminal 5 is such that the particle size of metal particles in a metal paste usually used for formation is about several μm, and a sufficient amount of metal particles must be present by sintering the metal paste. Therefore, 5 to 15 μm is preferable, and a range of 7 to 12 μm is more preferable.

  Further, in such an element substrate 1, a pair of external connection terminals 6 are provided on the back surface 23 of the base 2 so as to be electrically connected by soldering to an external circuit when the light emitting device is formed. A pair of through conductors 7 that electrically connect the element connection terminals 5 and the external connection terminals 6 are provided inside the base 2.

  Further, in order to reduce the thermal resistance of the base 2, a thermal via 8 is provided through the base 2 immediately below the light emitting element mounting portion 22 positioned substantially at the center of the bottom surface 24 of the recess 4. The other end of the thermal via 8 is in contact with one of the external connection terminals 6 at the back surface 23. Therefore, in the element substrate 1, one of the pair of external connection terminals 6 has a large area so as to cover the end portion of the thermal via 8 exposed at the substantially central portion of the back surface 23, and the other external connection terminal 6 is small. It is an area. The pair of external connection terminals 6 having different electrode areas are disposed asymmetrically with respect to the center line of the back surface 23. The planar shape and arrangement position of the external connection terminals 6 are not limited to this, but from the viewpoint of heat dissipation, the total electrode area of the pair of external connection terminals 6 is the entire area of the back surface 23 of the base 2. 70% or more is preferable.

  The position, shape, size, number, and the like of the thermal vias 8 are not limited to those shown in FIG. 2 and can be adjusted as appropriate. Furthermore, instead of disposing the thermal via 8, a heat dissipating layer may be disposed using a heat dissipating material similar to the constituent material of the thermal via in a direction parallel to the main surface 21. The material constituting the thermal via 8 is not particularly limited as long as it has a heat dissipation property, but a metal material containing silver, specifically, a metal material made of silver, silver and platinum, or silver and palladium is preferable. .

  The constituent material of the element connection terminal 5, the external connection terminal 6, and the through conductor 7 can be used without particular limitation as long as it is the same as that of the wiring conductor used for the element substrate. Specific examples of the constituent material of these wiring conductors include metal materials mainly composed of copper, silver, gold, and the like. Among such metal materials, a metal material composed of silver, silver and platinum, or silver and palladium is preferably used. Hereinafter, the element connection terminal 5, the external connection terminal 6, and the through conductor 7 may be collectively referred to as a “wiring conductor”.

  The wiring conductor is formed by firing a metal paste containing such a metal material powder. As the metal powder other than the metal material powder, a composite metal powder in which a metal oxide is deposited on the surface of conductive metal particles can be used. As the composite metal powder, for example, composite silver powder in which phosphor oxide and yttrium oxide are deposited on the surface of silver particles can be used.

  In the element connection terminal 5 and the external connection terminal 6, a conductive protective layer (not shown) that protects this layer from oxidation and sulfurization and has conductivity on the metal layer made of these metal materials, The structure formed so that the whole including an edge may be covered 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 embodiment of the element substrate of the present invention has been described above. For example, by mounting the light emitting element 11 such as a light emitting diode element on the mounting portion 22 using the element substrate 1 shown in FIG. A light-emitting device 10 whose cross-sectional view is shown in FIG. 3 can be manufactured.

  As shown in FIG. 3, the light emitting device 10 has a light emitting element 11 such as a light emitting diode element mounted on a mounting portion 22 positioned substantially at the center of the bottom surface 24 of the recess 4 of the element substrate 1 by a die bond agent 14 such as a silicone die bond agent. A pair of electrodes (not shown) is mounted and 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 element substrate 1 of the present invention in which the amount of warpage of the substrate itself is reduced. This is a light emitting device in which problems such as a difference in light directivity from the design and problems such as occurrence of disconnection due to positional deviation of bonding wires 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.

  The embodiments of the element substrate of the present invention and the light emitting device using the element substrate have been described above by way of example, but the 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.

  Moreover, the element substrate manufacturing method of the present invention will be described below using the element substrate 1 shown in FIG. 2 as an example. The element substrate 1 shown in FIG. 2 can be manufactured by, for example, a manufacturing method including the following (A) green sheet manufacturing step, (B) metal 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.

(A) Green sheet preparation process (A) process comprises the lower green sheet 2b, the upper green sheet 2a, and the frame which comprise the base | substrate of an element substrate using the glass-ceramics composition containing glass powder and ceramic powder. This is a step of producing the frame green sheet 3 to be performed. In this green sheet manufacturing process, the area shrinkage rate of the lower green sheet 2 b is adjusted to be lower than the area shrinkage rates of the upper green sheet 2 a and the frame green sheet 3.

  First, the production of the upper green sheet 2a and the frame green sheet 3 having the same area shrinkage rate will be specifically described. The upper green sheet 2a and the frame green sheet 3 are prepared by adding a binder resin and, if necessary, a plasticizer, a dispersant, a solvent, etc. to a glass ceramic composition containing glass powder and ceramic powder described below. The slurry can be produced by forming into a sheet shape 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 drying.

  About the upper side green sheet 2a, the sheet-like molding obtained above is used for lamination in the step (C) through the (B) metal paste layer forming step. The frame green sheet 3 was obtained by forming a through hole in the shape (circular shape) of the bottom surface 24 of the concave portion 4 by a normal method in this step in the central portion of the sheet-like molded product obtained above. Things are subjected to lamination in step (C). As a method of processing the frame body green sheet 3 in which the side surface of the recess 4 is tapered, for example, the frame body green sheet 3 is prepared as a plurality of green sheets having different through-hole sizes, and ( In the step C), there is a method in which corners are formed by a conventional method after laminating in a stepped manner from the bottom through the through holes in ascending order.

(Preparation of glass ceramic composition and slurry)
Although the glass powder used for the glass ceramic composition is not necessarily limited, 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.

  Moreover, it is preferable that a crystal | crystallization precipitates when it bakes at 800 degreeC or more and 930 degrees C or less. 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 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. 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 the 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 blending and mixing glass raw materials so as to be the glass as described above, producing glass by a melting method, and pulverizing the obtained glass 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. 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. As the laser diffraction / scattering particle size distribution measuring device, a laser diffraction / scattering particle size distribution measuring device (trade name: SALD2100) manufactured by Shimadzu Corporation was used.

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 is 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 resin and, if necessary, a plasticizer, a dispersant, a solvent and the like to the glass ceramic composition. As the binder resin, for example, polyvinyl butyral, acrylic resin or the like is preferably used. Moreover, as a compounding quantity of binder resin in a slurry, 5-15 mass parts is preferable with respect to 100 mass parts of glass ceramic compositions. As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate and the like are used. Moreover, as a solvent, organic solvents, such as toluene, xylene, 2-propanol, 2-butanol, are used suitably.

  The obtained slurry 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 to form the upper green sheet 2a. And the frame green sheet 3 is produced.

(Method for reducing area shrinkage)
Next, the production of the lower green sheet 2b having a smaller area shrinkage rate than the upper green sheet 2a and the frame green sheet 3 will be described. The lower green sheet 2b is formed into a sheet shape, for example, in the preparation of the upper green sheet 2a and the frame green sheet 3, the composition of the glass ceramic composition is adjusted, and the blending amount of the binder resin in the slurry is adjusted. The sheet can be produced as a green sheet having a smaller area shrinkage rate by a method such as press working later. One of these methods for reducing the area shrinkage rate may be performed alone, or two or more methods may be used in combination. In addition, any other method can be used without particular limitation as long as it can accurately reduce the area shrinkage rate of the green sheet.

<Adjustment of glass ceramic composition>
The lower green sheet 2b has a lower area shrinkage than the upper green sheet 2a by using a glass ceramic composition having a larger amount of ceramic powder than the glass ceramic composition used for the upper green sheet 2a. It can be a green sheet. When both alumina powder and zirconia powder are used as the ceramic powder as in the preferred glass ceramic composition described above, the amount of alumina powder alone or zirconia powder alone may be increased, or the amount of both May be increased. About the compounding quantity of the glass powder in a glass ceramic composition, the part which increased the compounding quantity of the ceramic powder should just be reduced.

As described above, in the element substrate 1, the area of the main surface 21 of the base 2 is 16 to 25 mm ² , and the area of the bottom surface 24 of the recess 4 is 50 to 70% of the area of the main surface 21 of the base 2. The thickness T of the element substrate 1 combined with the frame 3 is 0.6 to 1.2 mm, the thickness t2 of the base 2 is 40 to 60% of the thickness T of the element substrate 1, and the lower green sheet When the thickness after firing, that is, the thickness t2b of the base lower layer portion 2b is 10 to 20% of the thickness T of the element substrate 1, it is 0 than the area shrinkage rate of the upper green sheet 2a and the frame green sheet 3. The lower green sheet 2b having a lower area shrinkage of 2 to 1.0% is preferable.
For example, in order to obtain the lower green sheet 2b having such an area shrinkage rate in a state where the strength of the LTCC after sintering is sufficiently maintained, the amount of the ceramic powder blended with respect to the total amount of the glass ceramic composition is The ratio is preferably 1.05 to 1.16 times the blending amount of the ceramic powder used for the upper green sheet 2a.

  Further, for example, in the element substrate 1, when the thickness t2b of the base lower layer portion 2b is 10% of the thickness T of the element substrate 1, the area shrinkage rate of the upper green sheet 2a and the frame green sheet 3 is 0. The lower green sheet 2b having a lower area shrinkage of 4 to 1.0% is preferable, and in this case, the ceramic powder used for the upper green sheet 2a in a mass ratio of the amount of the ceramic powder to the total amount of the glass ceramic composition. It is preferable to set it as 1.05-1.16 times the compounding quantity of.

  Here, the mixing ratio of the ceramic powder and the glass powder in the glass ceramic composition and the mixing ratio of the alumina powder and the zirconia powder in the ceramic powder are also exemplified in the upper green sheet 2a in the glass ceramic composition used for the lower green sheet 2b. It is preferable to be within the preferable range. Therefore, when the area shrinkage rate of the lower green sheet 2b is adjusted by adjusting the composition of the glass ceramic composition, the composition of the glass ceramic composition of the upper green sheet 2a is within the above range in consideration of this. It is preferable to adjust the amount of the ceramic powder to the low side.

<Slurry adjustment>
The lower green sheet 2b may be a green sheet having a lower area shrinkage than the upper green sheet 2a by using a lower green sheet 2b having a smaller amount of binder resin than the slurry used for the upper green sheet 2a. it can.

  For example, in the element substrate 1 similar to the above, the lower green sheet 2b having an area shrinkage rate that is 0.2 to 1.0% lower than the area shrinkage rate of the upper green sheet 2a and the frame green sheet 3 is set between the green sheets. In order to obtain in a state in which the adhesion is sufficiently ensured, the blending amount of the binder resin with respect to 100 parts by mass of the glass ceramic composition in the slurry is, in mass ratio, 0. 0 of the blending amount of the binder resin used for the upper green sheet 2a. It is preferable to be 88 to 0.94 times.

  Further, for example, in the element substrate 1, when the thickness t2b of the base lower layer portion 2b is 10% of the thickness T of the element substrate 1, the area shrinkage rate of the upper green sheet 2a and the frame green sheet 3 is 0. The lower green sheet 2b having a lower area shrinkage of 4 to 1.0% is preferable. In this case, the amount of binder resin added to 100 parts by mass of the glass-ceramic composition in the slurry is expressed in terms of mass ratio. It is preferably 0.88 to 0.94 times the blending amount of the binder resin used in 2a.

  Here, the blending ratio of the glass ceramic composition and the binder resin in the slurry is preferably within the preferred range exemplified for the upper green sheet 2a even in the slurry used for the lower green sheet 2b. Therefore, when the area shrinkage rate of the lower green sheet 2b is adjusted by adjusting the composition of the slurry, considering this, the composition of the slurry of the upper green sheet 2a is within the above range and the amount of binder resin is high. It is preferable to make adjustments.

<Press processing>
The lower green sheet 2b can be produced as a green sheet having a lower area shrinkage than the upper green sheet 2a by forming the slurry into a sheet and then pressing to increase the packing density of the green sheet.
Here, when the lower green sheet 2b, the upper green sheet 2a, and the frame green sheet 3 are stacked in the stacking step of (C) below, usually, thermocompression bonding is performed in the same manner as stacking a green sheet for LTCC. The method to do is taken. The lower green sheet 2b is preferably formed by pressing a green sheet obtained by forming the slurry into a sheet shape at a pressure higher than the pressure condition for thermocompression bonding in the (C) lamination step.

For example, specific conditions for thermocompression bonding in the (C) laminating step are as follows: the area of the main surface 21 of the substrate 2 is 16 to 25 mm ² , and the area of the bottom surface 24 of the recess 4 is 50 of the area of the main surface 21 of the substrate 2. The thickness T of the element substrate 1 including the base 2 and the frame 3 is 0.6 to 1.2 mm, and the thickness t2 of the base 2 is 40 to 60 of the thickness T of the element substrate 1. %, And when the element substrate 1 in which the thickness t2b of the base lower layer portion 2b is 10 to 20% of the thickness T of the element substrate 1 is used, isotropic pressure is applied under the warm isotropic pressure. It is preferable to perform thermocompression bonding under conditions of 50 to 80 ° C. and 10 to 30 MPa with a hydraulic press of a (WIP: warm isostatic press) method.

  Here, when the thermocompression bonding in the (C) lamination step is performed at 50 to 80 ° C. and 10 to 30 MPa, the area is 0.2 to 1.0% lower than the area shrinkage rate of the upper green sheet 2a and the frame green sheet 3 In order to obtain the lower green sheet 2b having a shrinkage rate in a state in which the adhesion between the green sheets is sufficiently ensured, the green sheet obtained by forming the slurry into a sheet shape is heated at the same temperature as the above temperature. It is preferable to perform warm isostatic pressing under a pressure condition of 1.5 to 2 times.

  Further, for example, in the element substrate 1, when the thickness t2b of the base lower layer portion 2b is 10% of the thickness T of the element substrate 1, the area shrinkage rate of the upper green sheet 2a and the frame green sheet 3 is 0. The lower green sheet 2b having a lower area shrinkage of 4 to 1.0% is preferable. In this case, when the thermocompression bonding in the (C) lamination step is performed at 50 to 80 ° C. and 10 to 30 MPa, the slurry is formed into a sheet shape. It is preferable to subject the green sheet formed into a warm isotropic pressure to the same temperature as that described above and 1.5 to 2 times the pressure.

(B) Metal paste layer forming step In the step (B), the wiring conductor paste layer (element connection) is formed on the upper green sheet 2a and the lower green sheet 2b for constituting the base 2 obtained above by the following method. Metal paste layers such as the terminal paste layer 5, the external connection terminal paste layer 6, the through conductor paste layer 7) and the thermal via metal paste layer 8 are formed.

  First, a through conductor paste layer 7 and a thermal via metal paste layer 8 are formed on the upper green sheet 2a and the lower green sheet 2b using a metal paste. Specifically, a pair of through-holes and thermal vias 8 penetrating from the upper surface to the lower surface for disposing a pair of through conductors 7 are disposed at the predetermined positions of the upper green sheet 2a and the lower green sheet 2b, respectively. Through-holes for forming the through-conductor are formed, and the through-conductor paste layer 7 and the thermal via metal paste layer 8 are formed so as to fill these through-holes.

  Next, the element connection terminal paste layer 5 having the predetermined shape is formed so as to cover the through conductor paste layer 7 on the upper surface of the upper green sheet 2 a, that is, the surface to be the main surface 21 of the base 2. Also, a pair of external connection terminal paste layers 6 that are electrically connected to the through conductor paste layer 7 are formed on the lower surface of the lower green sheet 2 b, that is, the surface that becomes the back surface 23 of the base 2. One of the pair of external connection terminal metal paste layers 6 is formed in contact with the lower end of the thermal via metal paste layer 8. Thus, an upper green sheet 2a and a lower green sheet 2b with a metal paste layer are obtained. Although not shown, alignment marks for stacking may be formed on these green sheets.

  As the metal 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, an additive, or the like as necessary can be used. In addition, as said metal powder, the metal powder which consists of silver, the metal powder which consists of silver and platinum or silver and palladium is used preferably. A composite silver powder in which phosphorous oxide and yttrium oxide are deposited on the surface of spherical silver particles can also be used.

  As a method for forming the element connection terminal paste layer 5, the external connection terminal paste layer 6, the through conductor paste layer 7 and the thermal via metal paste layer 8, there is a method of applying and filling the metal paste by screen printing. Can be mentioned. The film thicknesses of the element connection terminal paste layer 5 and the external connection terminal paste layer 6 are adjusted so that the finally obtained element connection terminals 5 and external connection terminals 6 have a predetermined film thickness.

(C) Laminating step The upper green sheet 2a is overlaid on the lower green sheet 2b for forming the substrate 2 on which various metal paste layers are formed, obtained in the step (B), and further, The green body sheet 3 produced in the step (A) is overlapped and the whole is thermocompression bonded to obtain the unfired element substrate 1.

  Thermocompression bonding is a commonly used method for laminating and integrating ceramic green sheets. Usually, isotropic pressure is used to pressurize the object to be pressed with a uniform pressure (isotropic pressure) from all directions so that the green sheets are firmly joined to each other. For the same reason as described above, a warm isostatic press (WIP) system is preferably used. Specifically, the warm isostatic pressurization method (hereinafter also referred to as the WIP method) uses a heated fluid or liquid such as warm water as a pressure medium, and the green sheet laminate is pressurized via this pressure medium. By applying an isotropic pressure, the stacked green sheets are pressure-bonded with equal pressure from all directions.

  In the thermocompression bonding of the green sheet laminate by isotropic pressure pressing in the WIP method, the temperature condition is a temperature not exceeding the glass transition point of the binder resin contained in the above three types of green sheets and not higher than the glass transition point by 20 ° C. A range is preferred. For example, when polyvinyl butyral, acrylic resin, or the like is used as the binder resin, the preferred temperature range is generally between 50 and 80 ° C. Moreover, as a pressure condition, the pressure range of 10-30 MPa is preferable, and 15-25 MPa is more preferable. However, when the area shrinkage rate of the lower green sheet 2b is adjusted by pressing, isotropic pressure is applied by the WIP method within a pressure range of 1 / 1.5 to 1/2 of the pressure of the pressing. I do. The isotropic pressure is preferably about 3 to 20 minutes.

(D) Firing Step After the step (C), the obtained unfired element substrate 1 is degreased to remove the binder resin and the like as necessary, and fired to sinter the glass ceramic composition and the like. I do. Generally, the firing temperature is 800 to 930 ° C.

  The degreasing conditions are, for example, maintained at a temperature of 500 ° C. or more and 600 ° C. or less for 1 hour or more and 10 hours or less. When the degreasing temperature is less than 500 ° C. or the degreasing time is less than 1 hour, the binder resin 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 resin or the like can be sufficiently removed, and if it exceeds this, the productivity may be lowered.

  Further, in the firing, considering the acquisition of the dense structure of the base 2 and the frame 3 and the productivity, the time is preferably adjusted appropriately in the temperature range of 800 ° C to 930 ° C. 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 containing silver as a main component is used as the metal paste for the wiring conductor or thermal via, when the firing temperature exceeds 880 ° C., the metal paste is excessively softened. The shape may not be maintained.

  In this way, the unfired element substrate 1 is fired to obtain the element substrate 1, and after firing, as described above, the whole of the element connection terminals 5 and the external connection terminals 6 are covered as necessary. In general, a conductive protective layer used for conductor protection in a substrate for a light emitting element, such as nickel plating, chrome plating, silver plating, nickel / silver plating, gold plating, and nickel / gold plating, 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 an example of embodiment of the element substrate of this invention, the upper side green sheet 2a and the lower side green sheet 2b for comprising the base | substrate 2, the frame body green sheet 3, etc. are not necessarily single. The green sheets need not be formed, and a plurality of green sheets may be laminated as long as the area shrinkage rate is satisfied. Further, the order of forming each part can be changed as appropriate as long as the element substrate can be manufactured.

  In addition, the element substrate of the present invention is usually used when producing a wiring substrate such as an element substrate depending on its size, and a multi-piece connection substrate is produced, and a process for dividing the substrate is obtained. You may produce by the method of producing a wiring board. 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.

  Although the element substrate of the present invention using LTCC as the inorganic insulating material, the manufacturing method thereof, and the light emitting device have been described above, the embodiment of the element substrate of the present invention when alumina ceramic is used as the inorganic insulating material is described below. The structure and manufacturing method will be briefly described.

  For example, when an element substrate similar to the element substrate 1 using LTCC shown in FIG. 2 is manufactured using alumina ceramics, the area shrinkage ratio of the lower green sheet 2b is set to the upper green sheet 2a and the frame green sheet 3. Examples of a method of designing lower than the area shrinkage rate include a method of reducing the amount of the binder resin in the slurry for the lower green sheet 2b, or pressing with a pressure equal to or higher than the pressurizing condition of the lamination process. An element substrate using such alumina ceramics can be manufactured, for example, as follows.

(A ′) Green sheet production process In place of the glass ceramic composition (LTCC composition) containing glass powder and ceramic powder, the above-mentioned (A) green The upper green sheet 2a and the frame green sheet 3 are obtained through the same process as the sheet manufacturing process.

  Specifically, as the composition for alumina ceramics mainly composed of alumina, the same composition for alumina ceramics that is usually used when preparing alumina ceramics is prepared. A slurry is obtained by adding a binder resin and, if necessary, a plasticizer, a dispersant, a solvent, and the like to the composition for alumina ceramics in the same manner as in preparing a slurry for LTCC. The upper green sheet 2a and the frame green sheet 3 are produced by molding into a sheet shape having a predetermined shape and film thickness so that the shape and film thickness after firing are within the above desired range by a method, etc. Is done.

  The lower green sheet 2b can be produced as a green sheet having a smaller area shrinkage than the upper green sheet 2a by reducing the amount of binder resin in the slurry when the upper green sheet 2a is produced. The amount of reduction in the area shrinkage rate of the lower green sheet 2b relative to the upper green sheet 2a can be the same as in the case of the LTCC, and the reduction rate of the binder resin amount in the slurry to achieve this can be the same.

  Further, the conditions for pressing the lower green sheet 2b after the slurry is formed into a sheet shape may be adjusted in the same manner as in the case of the LTCC, thereby reducing the area shrinkage with respect to the upper green sheet 2a. The lower green sheet 2b whose amount is appropriately adjusted can be produced.

(B ′) Metal paste layer forming step In the case of an element substrate using alumina ceramics, the metal material constituting the metal layer such as the wiring conductor layer and the thermal via is mainly composed of a refractory metal such as tungsten or molybdenum. A metal material is used. That is, in place of the silver-based metal paste used in the production of the LTCC element substrate, a highly heat-resistant metal paste containing a refractory metal such as tungsten or molybdenum as a main component was prepared, and the above (B) The same process as the metal paste layer forming process is performed. Thus, a metal paste layer is formed on the upper green sheet 2a and the lower green sheet 2b for constituting the base 2 obtained in the step (A ′).

(C ′) Lamination Step An unfired element substrate 1 is obtained through the same steps as in the above (C) lamination.

(D ′) Firing Step After the step (C ′), the obtained unfired element substrate 1 is degreased to remove the binder resin and the like as necessary, and the alumina ceramic composition is sintered. For firing. Generally, the firing temperature is 1400-1700 ° C. 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 while maintaining a non-oxidizing atmosphere in a reducing atmosphere such as a hydrogen atmosphere, an inert gas atmosphere, or a vacuum.

  In this way, the unfired element substrate 1 is fired to obtain the element substrate 1. A conductive protective layer similar to that of the element substrate 1 using the LTCC is disposed on the element connection terminal 5 and the external connection terminal 6 of the obtained element substrate 1 so as to cover the whole as necessary. You may set up.

  Examples of the present invention will be described below. The present invention is not limited to these examples. An element substrate of an example and a comparative example having the same structure as shown in FIG. 2 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.

[Example of preparation of glass ceramic composition]
The glass powder used for preparation of the green sheets of the following examples and comparative examples was produced as follows.
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%, the glass raw material as Na ₂ O is 2 mol% The glass raw material was put in a platinum crucible and melted at 1600 ° C. for 60 minutes. Thereafter, the molten glass was poured out and cooled. The obtained glass was pulverized with an alumina ball mill for 40 hours to produce a glass powder having a D ₅₀ of 2.5 μm. In addition, ethyl alcohol was used as a solvent for pulverization.
As ceramic powder, the product name: AL-45H manufactured by Showa Denko KK was used for the alumina powder, and the product name: HSY-3F-J manufactured by Daiichi Rare Elemental Chemical Co., Ltd. was used for the zirconia powder.

  The glass ceramic composition A was manufactured by mixing and mixing the above-mentioned glass powder at 35% by mass, alumina powder at 40% by mass, and zirconia powder at 25% by mass. Moreover, the glass ceramic composition B was manufactured by mix | blending and mixing so that a glass powder might be 32 mass%, an alumina powder might be 43 mass%, and a zirconia powder might be 25 mass%. Furthermore, the glass ceramic composition C was manufactured by mix | blending and mixing so that a glass powder might be 32 mass%, an alumina powder might be 40 mass%, and a zirconia powder might be 28 mass%.

[Example 1]
Using the glass ceramic composition obtained in the above preparation example, an upper green sheet 2a, a lower green sheet 2b, and a frame green sheet 3 for producing the base 2 and the frame 3 of the element substrate 1 were produced. .
First, 50 g of the glass ceramic composition A, 15 g of an organic solvent (toluene, xylene, 2-propanol, 2-butanol mixed in a mass ratio of 4: 2: 2: 1), a plasticizer (diphthalate di- 2.5 g of 2-ethylhexyl), 5 g of polyvinyl butyral (trade name: PVK # 3000K) as a binder resin, and 0.5 g of a dispersant (product name: BYK180, trade name: BYK180) are blended. The slurry A was prepared by mixing. A slurry B was prepared in the same manner as described above except that the glass ceramic composition A was replaced with the glass ceramic composition B.

  The slurry A is applied on a PET film by a doctor blade method, and dried green sheets are laminated to form an upper green sheet 2a having a substantially flat plate shape with a thickness after firing of 0.4 mm. Was the same as the upper side green sheet 2a, and the frame body green sheet 3 having a substantially circular shape with a diameter of 4.4 mm after firing and a frame height of 0.5 mm was prepared.

Also, slurry B is applied on a PET film by a doctor blade method and dried green sheets are laminated to produce a lower green sheet 2b that is substantially flat and has a thickness after firing of 0.1 mm. did.
In this embodiment, the element substrate 1 is manufactured as a multi-piece connection substrate, and is divided into one after the firing, which will be described later, to form a substantially square element substrate 1 having an outer dimension of 5 mm × 5 mm. . The following description explains one section which becomes one element substrate 1 after the division among the multi-piece connection substrates.

  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%. Then, the mixture was kneaded in a porcelain mortar for 1 hour, and further dispersed three times with three rolls to produce a metal paste.

  With respect to the upper green sheet 2a and the lower green sheet 2b, a portion corresponding to the pair of through conductors 7 and a portion corresponding to the thermal via 8 are formed in a through hole having a diameter of 0.3 mm by using a hole puncher, and vertical and horizontal Through-holes each having a size of 1.0 mm were formed, and the metal paste obtained above was filled by screen printing to form a through-conductor paste layer 7 and a thermal via metal paste layer 8.

  Next, the element connection terminal paste layer 5 having the predetermined shape was formed so as to cover the through conductor paste layer 7 on the upper surface of the upper green sheet 2 a, that is, the surface to be the main surface 21 of the base 2. In addition, a pair of external connection terminal paste layers 6 that are electrically connected to the through conductor paste layer 7 were formed on the lower surface of the lower green sheet 2 b, that is, the surface to be the back surface 23 of the base 2. One of the pair of external connection terminal paste layers 6 was formed in contact with the lower end of the thermal via metal paste layer 8. Thus, an upper green sheet 2a and a lower green sheet 2b with a metal paste layer were obtained.

  The upper green sheet 2a is overlaid on the lower green sheet 2b for forming the base 2 on which the various metal paste layers are formed, and the frame green sheet 3 produced above is further formed thereon. And the whole was thermocompression bonded to obtain an unfired multi-piece connected substrate. The thermocompression bonding was performed under conditions of a temperature of 70 ° C., a pressure condition of 20 MPa, and a pressurization time of 10 minutes by WIP isotropic pressure.

  After putting the cut line for dividing such that each section of the unfired element substrate 1 has an outer size of 5 mm × 5 mm after firing on the unfired multi-piece connection substrate obtained above, it is at 550 ° C. for 5 hours. Holding and degreasing, and holding at 870 ° C. for 30 minutes and firing were performed to produce a multi-piece connected substrate. The obtained multi-piece connection substrate was divided along the cut line to manufacture the element substrate 1.

  The obtained element substrate 1 is divided by a dicing machine so that the cross section of the element substrate 1 includes the XX line shown in FIG. 2A, and the fracture surface shown in FIG. The amount of warpage of the upper surface of the substrate body 2 was measured with a length measuring microscope. The results are shown in Table 1.

Also, slurry A is coated on a PET film by the doctor blade method and dried green sheets are laminated, and the upper and lower green sheets are 40 mm in length and 1.0 mm in length on the main surface and 1.0 mm in thickness. A green sheet for measuring the area shrinkage of 2a was prepared. This was degreased by holding at 550 ° C. for 5 hours under the same conditions as the firing conditions of the element substrate 1, and further holding at 870 ° C. for 30 minutes for baking. The vertical and horizontal lengths after firing were measured with a digital caliper to determine the area Sa (mm ² ). The area shrinkage ratio Da of the upper green sheet 2a was determined as (1600−Sa) / 1600 × 100.
Similarly, the area shrinkage ratio Db of the lower green sheet 2b was obtained, and the difference from Da: Da-Db was obtained. The results are shown in Table 1.

[Example 2]
A slurry C was prepared in the same manner as the slurry A except that the glass ceramic composition C was used in place of the glass ceramic composition A in Example 1. An element substrate 1 was produced in the same manner as in Example 1 except that the slurry C was used to produce the lower green sheet 2b. About the obtained element substrate 1, the amount of warpage was measured in the same manner as in Example 1. Further, in the same manner as in Example 1, the difference between the area shrinkage ratio Db of the lower green sheet 2b and the area shrinkage ratio Da of the upper green sheet 2a: Da-Db was obtained. The results are shown in Table 1.

[Example 3]
15 g of an organic solvent (toluene, xylene, 2-propanol, 2-butanol mixed at a mass ratio of 4: 2: 2: 1) to 50 g of the glass ceramic composition A obtained in the above preparation example, plasticizer 2.5 g of (di-2-ethylhexyl phthalate), 4.5 g of polyvinyl butyral (trade name: PVK # 3000K) as a binder resin, and further a dispersant (trade name: BYK180, manufactured by BYK Chemie) 0.5 g of was mixed and mixed to prepare slurry D. An element substrate 1 was produced in the same manner as in Example 1 except that the slurry D was used to produce the lower green sheet 2b. About the obtained element substrate 1, the amount of warpage was measured in the same manner as in Example 1. Further, in the same manner as in Example 1, the difference between the area shrinkage ratio Db of the lower green sheet 2b and the area shrinkage ratio Da of the upper green sheet 2a: Da-Db was obtained. The results are shown in Table 1.

[Example 4]
In Example 1, both the upper green sheet 2a and the lower green sheet 2b were prepared using the slurry A, and the lower green sheet 2b was laminated at the temperature of 70 ° C. by the isotropic pressure pressing of the WIP method before the lamination. An element substrate 1 was manufactured in the same manner as in Example 1 except that the treatment was performed under conditions of 35 MPa and a pressing time of 10 minutes. About the obtained element substrate 1, the amount of warpage was measured in the same manner as in Example 1. Further, in the same manner as in Example 1, the difference between the area shrinkage ratio Db of the lower green sheet 2b and the area shrinkage ratio Da of the upper green sheet 2a: Da-Db was obtained. The results are shown in Table 1.

[Comparative example]
An element substrate 1 was produced in the same manner as in Example 1 except that the upper green sheet 2a and the lower green sheet 2b were both produced using the slurry A in Example 1. About the obtained element substrate 1, the amount of warpage was measured in the same manner as in Example 1. Further, in the same manner as in Example 1, the difference between the area shrinkage ratio Db of the lower green sheet 2b and the area shrinkage ratio Da of the upper green sheet 2a: Da-Db was obtained. The results are shown in Table 1.

  The light-emitting element substrate of the present invention is a light-emitting element substrate in which the amount of warpage is reduced to within 30 μm in the light-emitting element substrate having a recess and mounting the light-emitting element on the bottom surface. In the light emitting device of the present invention, due to the element substrate of the present invention in which the amount of warpage is reduced in this way, the positional deviation and inclination of the light emitting element are reduced, the light directivity is 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.

DESCRIPTION OF SYMBOLS 1 ... Element board | substrate, 2 ... Base | substrate, 3 ... Frame, 4 ... Recessed part, 5 ... Element connection terminal, 6 ... External connection terminal, 7 ... Through-conductor, 8 ... Thermal via 10 ... Light-emitting device, 11 ... Light-emitting element, 12 DESCRIPTION OF SYMBOLS ... Bonding wire, 13 ... Sealing layer, 14 ... Die bond agent 21 ... Main surface of base | substrate, 22 ... Light emitting element mounting part, 23 ... Back surface of base | substrate, 24 ... Bottom face of recessed part

Claims (7)

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,
The amount of warpage, which is a difference in height between the highest portion and the lowest portion of the upper main surface in the cross section, measured using a cross section of the base perpendicular to the main surface passing through the center point of the upper main surface is 30 μm or less. A substrate for a light-emitting element.   The light emitting element substrate according to claim 1, wherein the amount of warpage is 25 μm or less.   The base sheet and the frame body are made of a fired body of a laminate in which a plurality of ceramic green sheets are laminated, and at least the number of green sheets to be the base is two or more, and constitutes the lowermost layer of the laminate The substrate for a light-emitting element according to claim 1, wherein the area shrinkage rate at the time of firing is smaller than the area shrinkage rate at the time of firing of the green sheet constituting other than the lowermost layer. The area of the main surface of the substrate is 16 to 25 mm ² , the area of the bottom surface of the recess is 50 to 70% of the area of the main surface of the substrate, the total thickness of the substrate and the frame is 0.6 to 1.2 mm; The thickness of the base is 40 to 60% of the total thickness, and the thickness after firing of the green sheet constituting the lowermost layer is 10 to 20% of the total thickness. A substrate for a light emitting device as described in 1. above.   When the area shrinkage rate is defined as the area reduction rate of the main surface when a flat green sheet having a vertical and horizontal length of 40 mm and a thickness of 1.0 mm is used as the fired body, the laminate The substrate for light emitting elements according to claim 4, wherein the area shrinkage rate of the green sheet constituting the lowermost layer of the body is 0.2 to 1.0% smaller than the area shrinkage rate of the green sheet constituting other than the lowermost layer.   The light emitting device 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 a glass ceramic composition containing glass powder and ceramic powder. substrate. The light emitting element substrate according to any one of claims 1 to 6,
And a light emitting device mounted on the light emitting device substrate.

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