JP2013149637A - Light emitting device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve color tone unevenness, etc. and light extraction efficiency in a light emitting device having a lens shaped sealing layer.SOLUTION: A light emitting device includes: a substrate which is formed by an inorganic insulation material and has a mounting surface having a part serving as a mounting part on which a light emitting element is mounted; an element connection terminal formed on the mounting surface of the substrate; a dam layer formed on the mounting surface of the substrate so as to enclose the mounting part and made of light transmissivity glass; the light emitting element mounted on the mounting part of the substrate and electrically connecting with the element connection terminal; and a sealing layer provided at an inner region of the dam layer so as to cover the light emitting element and formed by a resin.

Description

  The present invention relates to a light emitting device and a method for manufacturing the same, and more particularly to a light emitting device having a lens-shaped sealing layer and a method for manufacturing the light emitting device.

  In recent years, a light emitting device using a light emitting diode (LED) element has been provided with a sealing layer made of silicone resin or epoxy resin in order to protect the light emitting element mounted on the substrate and the wiring conductor layer. A light-emitting device that obtains white light emission in combination with a light-emitting element by dispersing a fluorescent material in a layer has been put into practical use.

  In order to improve color unevenness and the like in such a light emitting device, it has been considered to form the sealing layer into a lens shape having a spherical outer surface. That is, by mounting a light emitting element on a flat substrate and potting a fluid resin material so as to cover the light emitting element, a hemispherical lens-shaped translucent sealing layer is formed. A light emitting device has been developed in which the length of the path through which the emitted light passes through the sealing layer is equal in all directions.

  However, when a resin material having fluidity is potted, the resin material tends to wet and spread on the substrate, so that a depression is likely to occur on the outer surface of the interface between the resin material and the substrate. And in the sealing layer of such a shape, there is a problem that the light extraction efficiency (radiation efficiency) is likely to be low as a result of the transmitted light being totally reflected on the surface of the recessed portion and confined inside the sealing layer. there were.

  In order to improve this point, an annular member is mounted on the base so as to surround the mounting portion of the light emitting element, and the light emitting element is mounted on the mounting portion formed so as to protrude higher than the annular member. There has been proposed a light-emitting device that is mounted and further provided with a translucent member so as to cover the light-emitting element inside the annular member (see, for example, Patent Document 1).

  However, in the light emitting device described in Patent Document 1, the annular member is made of a metal such as an Fe—Ni—Co alloy or an Fe—Ni alloy, or a ceramic material such as alumina ceramics. Since the annular member reflects or absorbs part of the transmitted light, the light extraction efficiency cannot be sufficiently increased.

JP 2005-340543 A

  The present invention has been made to solve the above-described problems, and in a light-emitting device having a lens-shaped sealing layer, it improves unevenness of color tone and improves light extraction efficiency, thereby increasing the brightness. The purpose is to obtain luminescence.

  The light-emitting device of the present invention is made of an inorganic insulating material, a part of which has a mounting surface serving as a mounting portion on which a light-emitting element is mounted, an element connection terminal formed on the mounting surface of the base, A damming layer made of translucent glass formed on the mounting surface of the base so as to surround the mounting portion, and mounted on the mounting portion of the base and electrically connected to the element connection terminal. And a sealing layer made of a resin provided to cover the light emitting element in a region inside the damming layer.

  In the light emitting device of the present invention, the thermal expansion coefficient of the blocking layer is preferably smaller than the thermal expansion coefficient of the substrate. The damming layer has an annular planar shape, and preferably has a height of 10 to 50 μm and a width of 80 to 300 μm. The sealing layer preferably has a substantially hemispherical three-dimensional shape. Furthermore, the sealing layer is preferably a layer formed by potting a curable resin material having fluidity.

  The manufacturing method of the light emitting device of the present invention includes a base having a mounting surface made of an inorganic insulating material, a part of which is a mounting portion on which the light emitting element is mounted, and an element connection terminal formed on the mounting surface of the base And manufacturing a light emitting element substrate having a blocking layer made of translucent glass formed so as to surround the mounting portion on the mounting surface of the base, and the base of the light emitting element substrate A step of mounting a light emitting element on the mounting portion, electrically connecting the light emitting element to the element connection terminal, and fluidity in a region inside the blocking layer on the mounting surface of the base. And a step of potting and curing a curable resin material to form a sealing layer made of a resin covering the light emitting element.

  According to the light emitting device of the present invention, high luminance light emission with improved light extraction efficiency and improved color unevenness can be obtained.

1 shows a first embodiment of a light emitting device of the present invention, (a) is a plan view seen from the upper surface (mounting surface) side, (b) is a cross-sectional view taken along line XX in (a). is there. In the light-emitting device of this invention, it is an expanded sectional view which shows the relationship between the height of a damming layer, the width | variety, the height of the top part of a sealing layer, etc. FIG. 2 shows a second embodiment of the light emitting device of the present invention, (a) is a plan view seen from the upper surface (mounting surface) side, (b) is a cross-sectional view taken along line YY in (a). is there.

Hereinafter, although an embodiment of the present invention is described, the present invention is not limited to this.
A light-emitting device according to an embodiment of the present invention includes a base having a mounting surface that is made of an inorganic insulating material, a part of which is a mounting portion on which the light-emitting element is mounted, and an element connection terminal formed on the mounting surface of the base. A damming layer made of translucent glass formed so as to surround the mounting portion on the mounting surface, and a light emitting element mounted on the mounting portion of the base and electrically connected to the element connection terminal And a sealing layer made of a resin provided to cover the light emitting element in a region inside the damming layer on the mounting surface.

  In this light-emitting device, the flow when the resin material constituting the sealing layer is potted is blocked by the blocking layer made of translucent glass, so that the resin material can reach the outer region on the mounting surface of the substrate. Wet and spread are suppressed. Therefore, by a simple and inexpensive potting method, a stable sealing layer having a hemispherical lens shape, for example, can be formed, and the path lengths through which light emitted from the light emitting element passes through the sealing layer is made equal in all directions, and stable. A light emitting device having good optical characteristics can be obtained.

  In addition, since the blocking layer is made of translucent glass and the blocking layer hardly reflects or absorbs the light transmitted through the sealing layer, a light emitting device with excellent light extraction efficiency and high emission luminance is obtained. can get. Furthermore, since the damming layer can be formed by a method such as simultaneous firing with the substrate, it is easy to adjust the height of the damming layer and the width that becomes the barrier in the direction of spreading, and the light emitting device as a whole can be easily manufactured. is there.

  Hereinafter, a first embodiment of a light emitting device of the present invention will be described with reference to the drawings. In the first embodiment, a light emitting element having a pair of electrodes on the lower surface is mounted on a pair of element connection terminals provided on a base, and is electrically connected by metal-to-metal connection such as gold-tin eutectic solder. An example of a light emitting device that has been manufactured is shown. The connection method of the light-emitting elements is not limited to this, and any light-emitting device in which the light-emitting elements are connected by flip chip bonding, such as connection by a bump, may be used.

  FIG. 1A is a plan view of the light emitting device of the first embodiment as viewed from the upper surface (mounting surface) side, and FIG. 1B shows the light emitting device of FIG. It is sectional drawing cut | disconnected by. FIG. 1A shows a state where the sealing layer is removed.

  This light-emitting device 1 has a substantially flat base 2 having a square planar shape. The substrate 2 is made of an inorganic insulating material and has an upper surface on which the light emitting element is mounted as a mounting surface 21. The opposite surface is referred to as a non-mounting surface 22. The shape, thickness, size, etc. of the substrate 2 are not particularly limited, and can be generally the same as that used as a substrate for mounting a light emitting element to form a light emitting device. In the present specification, the “substantially flat substrate” means a flat surface at a level at which the upper main surface and the lower main surface, that is, the mounting surface 21 and the non-mounting surface 22 can be recognized as a flat plate shape at the visual level. It refers to a certain substrate. Similarly, the abbreviations indicate levels that can be recognized at the visual level unless otherwise specified.

  Examples of the inorganic insulating material constituting the substrate 2 include an aluminum oxide sintered body (alumina ceramic), an aluminum nitride sintered body, a mullite sintered body, and a glass ceramic composition containing glass powder and ceramic powder. Body (Low Temperature Co-fired Ceramics, hereinafter referred to as LTCC) and the like. In the present invention, from the viewpoints of high reflectivity, ease of manufacture, easy processability, economy and the like, the inorganic insulating material constituting the substrate 2 is preferably LTCC. The raw material composition, sintering conditions, and the like of the sintered body of the glass ceramic composition constituting the substrate 2 will be described in the manufacturing method described later.

  The base body 2 preferably has a bending strength of, for example, 250 MPa or more from the viewpoint of suppressing damage or the like when the light emitting element is mounted and when it is used thereafter. The base body 2 has a mounting portion 3 for mounting the light emitting element at a substantially central portion of the mounting surface 21.

  On the mounting surface 21 of the base 2, a pair (anode and cathode) of element connection terminals 4 is provided. These element connection terminals 4 are arranged so that one end thereof overlaps the mounting portion 3 so that a metal-to-metal connection is possible via a pair of electrodes on the lower surface of the light emitting element to be mounted and gold-tin solder or the like. Is formed. A pair of external connection terminals 5 serving as an anode and a cathode electrically connected to an external circuit are provided on the non-mounting surface 22 of the base 2. The anode-side and cathode-side element connection terminals 4 are electrically connected to the pair of external connection terminals 5 formed on the non-mounting surface 22 via connection vias 6 embedded in the base 2. It is connected.

  Regarding the element connection terminal 4, the external connection terminal 5, and the connection via 6 embedded in the substrate 2, the anode and the cathode are short-circuited from the element connection terminal 4 → the connection via 6 → the external connection terminal 5 → the external circuit. As long as it is electrically connected without any limitation, the position and shape of the arrangement are not limited.

  The constituent materials of the element connection terminals 4, the external connection terminals 5, and the connection vias 6 can be used without particular limitation as long as they are the same constituent materials as the wiring conductors used for the substrate on which the light emitting element is usually mounted. Specific examples of the constituent material of the element connection terminal 4, the external connection terminal 5, and the connection via 6 include conductive 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. These metal materials will be specifically described in a light emitting device manufacturing method described later. As for the thickness of the element connection terminal 4 and the external connection terminal 5, 5-15 micrometers is preferable.

  In addition, in the element connection terminal 4 and the external connection terminal 5, a conductive protective layer (not shown) for protecting this layer from oxidation or sulfuration is provided on the edge made of the metal material. The structure formed so that the whole containing this 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 layers made of nickel plating, chromium plating, silver plating, nickel / silver plating, gold plating, nickel / gold plating, and the like.

  In the present invention, as the conductive protective layer for covering and protecting the element connection terminals 4 and the external connection terminals 5, for example, the element connection terminals 4 are bumps made of solder, gold, gold-tin eutectic, etc. It is preferable to use a metal plating layer having a gold plating layer at least as the outermost layer from the viewpoint of obtaining a good metal-to-metal connection. The conductive protective layer may be formed of only a gold plating layer, but a nickel / gold plating layer formed by gold plating on nickel plating is more preferable. 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 μm for the gold plating layer.

  On the mounting surface 21 of the substrate 2, a damming layer 7 made of glass is formed so as to surround the light emitting element mounting portion 3 and the element connection terminal 4 formed so as to overlap with a part thereof. .

Hereinafter, the glass constituting the blocking layer 7 will be described.
The glass constituting the damming layer 7 is preferably borosilicate glass containing at least one selected from SiO ₂ , B ₂ O ₃ , and Na ₂ O and K ₂ O as a constituent component.

  This glass is preferably made of only glass powder having a softening point (Ts) of 650 to 800 ° C., and is fired from a composition not containing ceramic powder. Usually, in order to obtain a dense sintered body by firing glass powder, the firing temperature needs to exceed the softening point of the glass powder. When the softening point of the glass powder for forming the blocking layer 7 exceeds 800 ° C., the metal layer mainly composed of silver of the unfired LTCC base that is usually fired at the same time is excessively fired during firing. There is a possibility that the predetermined shape cannot be maintained due to softening. Therefore, by using a glass powder having a softening point of 650 ° C. or lower, preferably 700 ° C. or lower, the weir containing the glass powder without causing deformation due to excessive softening of the metal layer mainly composed of silver. The composition for forming the stopper layer and the unfired LTCC substrate having a metal layer mainly composed of silver can be fired simultaneously. The softening point (Ts) of the glass powder is more preferably 730 ° C. or higher and 780 ° C. or lower.

  In addition, the thermal expansion coefficient of the glass constituting the blocking layer 7 is preferably smaller than the thermal expansion coefficient of the substrate 2. The reason is that if the coefficient of thermal expansion of the glass constituting the damming layer 7 is larger than that of the base 2, a tensile force is applied from the base 2 to the glass constituting the damming layer 7, and the glass breaks, or heat or impact occurs. It is easy to break. By reducing the coefficient of thermal expansion of the glass constituting the damming layer 7, a compressive force acts on the glass from the base 2, and the glass becomes difficult to break.

Specifically, as glass powder for forming the glass constituting the damming layer 7, SiO ₂ is 78 to 83%, B ₂ O ₃ is 16 to 18%, Al is expressed in terms of mol% in terms of oxide. 0 to 0.5% of ₂ O ₃ , 0.9 to 4% in total of at least one selected from Na ₂ O and K ₂ O, 0 to 0 in total of at least one selected from CaO, SrO and BaO A glass powder containing 0.6% is mentioned. Hereinafter, in the description of the glass composition, “%” represents an oxide conversion mol% unless otherwise specified.

In the glass powder, SiO ₂ serves as a glass network former and is an essential component for increasing chemical durability, particularly acid resistance. If the SiO ₂ content is less than 78%, the acid resistance may be insufficient. On the other hand, if the content of SiO ₂ exceeds 83%, the glass transition point, also referred to as the glass softening point or Tg, may be excessively high.

B ₂ O ₃ is an essential component that becomes a glass network former. If the content of B ₂ O ₃ is less than 16%, the softening point may become excessively high, and the glass may become unstable. On the other hand, if the content of B ₂ O ₃ exceeds 18%, it is difficult to obtain a stable glass, and chemical durability may be lowered.

Al ₂ O ₃ is an optional component that may be added in a range of 0.5% or less in order to enhance the stability and chemical durability of the glass. When the content of Al ₂ O ₃ exceeds 0.5%, the transparency of the glass may be lowered.

Na ₂ O and K ₂ O are essential components to be added in a range where the total content becomes 0.9 to 4% in order to lower the softening point and the glass transition point. If the total content of Na ₂ O and K ₂ O is less than 0.9%, the softening point and the glass transition point may be too high. On the other hand, when the total content of Na ₂ O and K ₂ O exceeds 4%, chemical durability, particularly acid resistance may be lowered, and electrical insulation may be lowered.
Na ₂ O and K ₂ O preferably contain at least one selected from these.

  CaO, SrO, and BaO may be added within a range where the total content of these does not exceed 0.6% in order to lower the softening point and the glass transition point and increase the stability of the glass. It is an ingredient. If the total content of CaO, SrO, and BaO exceeds 0.6%, the acid resistance may decrease.

  In addition, the said glass powder is not necessarily limited to what consists only of the said component, In the range which does not impair the effect of this invention, it can contain components other than the above. In this embodiment, lead oxide is not contained. When it contains components other than the above, the total content is preferably 10% or less.

  The glass powder constituting the damming layer 7 is obtained by manufacturing glass having the above composition by a melting method and pulverizing it by a dry pulverization method or a wet pulverization method. In the case of the wet pulverization method, it is preferable to use water or ethyl alcohol as a solvent. Examples of the pulverizer include a roll mill, a ball mill, and a jet mill.

The 50% particle size (D ₅₀ ) of the glass powder constituting the damming layer 7 is preferably 0.3 μm or more and 4 μm or less. If D ₅₀ of the glass powder is less than 0.3 [mu] m, handling the glass powder is likely to agglomerate are not only difficult, uniform dispersion becomes difficult. On the other hand, if the D ₅₀ of the glass powder exceeds 4μm, there is a possibility that increase and insufficient sintering of the glass softening temperature is generated. For example, the particle size may be adjusted by classification as necessary after pulverization. In the present specification, the 50% particle size (D ₅₀ ) refers to a value measured using a laser diffraction / scattering particle size distribution analyzer.

  A paste can be obtained by adding a binder and, if necessary, a plasticizer, a dispersant, a solvent and the like to the glass powder constituting the damming layer 7.

  As the binder, for example, polyvinyl butyral, acrylic resin and the like can be suitably used. As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate and the like can be used. As the solvent, organic solvents such as toluene, xylene, 2-propanol and 2-butanol can be suitably used.

  In the first embodiment of the present invention, the blocking layer 7 is obtained by firing a composition containing a borosilicate glass powder composed of such components, and the borosilicate glass powder having the composition is Thus, the paste is formed by screen printing and baking.

  The planar shape of the damming layer 7 made of glass is not particularly limited as long as it is a frame shape or a ring shape having a predetermined width so as to surround the light emitting element mounting portion 3. Moreover, you may have a notch partially. A rectangular frame shape or an annular shape is preferable, and an annular shape is particularly preferable from the viewpoint of forming a hemispherical lens-shaped sealing layer.

  The height h and width w of the blocking layer 7 shown in an enlarged manner in FIG. 2 are preferably in the ranges shown below. That is, by potting a curable resin material having fluidity, in order to form a sealing layer 8 having a hemispherical lens shape with a height H to the top being close to ½ of the diameter D, the blocking layer 7 The height h is preferably 10 μm or more. If the height h of the damming layer 7 is less than 10 μm, the fluid resin material extends beyond the upper surface of the damming layer 7 during potting, and the hemispherical lens shape cannot be maintained. Further, the height h of the blocking layer 7 is preferably 50 μm or less in order to suppress an excessive increase in the number of steps such as screen printing for forming the blocking layer 7 and increase productivity.

  The width w of the blocking layer 7 serving as a barrier in the direction of wetting and spreading is not particularly limited, but is preferably in the range of 80 to 300 μm. If the width w of the damming layer 7 is narrower than 80 μm, it is difficult to form it by screen printing. When the width w of the damming layer 7 exceeds 300 μm, the damming layer 7 itself contacts the cathode mark formed on the substrate 2 or the glass flows into the dividing groove when it is formed as a connecting substrate. There is a risk. In FIG. 2, reference numeral 9 denotes a light emitting element mounted. The light emitting element 9 and the sealing layer 8 will be described later.

  In order to reduce the thermal resistance of the base 2, a thermal via (not shown) can be embedded in the base 2. The thermal via is, for example, a columnar one smaller than the mounting portion 3 of the light emitting element, and is preferably disposed from the non-mounting surface 22 to an intermediate position in the thickness direction of the base 2. With this arrangement, the flatness of the entire mounting surface 21, particularly the mounting portion 3, can be improved, the thermal resistance can be reduced, and the inclination when the light emitting element is mounted can be suppressed.

  And in the light-emitting device 1 of the 1st Embodiment of this invention, LED elements etc. are mounted in the mounting part 3 provided in the approximate center part of the mounting surface 21 of the base | substrate 2 by which the thermal via etc. were embed | buried in this way. A light emitting element 9 is mounted. The light emitting element 9 has a pair of electrodes such as bumps on the lower surface, and is electrically connected to the element connection terminal 4 by an intermetallic connection 3a through solder, gold, gold-tin eutectic or the like.

  Further, a sealing layer 8 made of a translucent resin formed in a substantially hemispherical shape so as to cover the light emitting element 9 is provided in a region inside the blocking layer 7 on the mounting surface 21 of the base 2. Yes. As the resin constituting the sealing layer 8, a silicone resin is preferably used because it is excellent in terms of light resistance and heat resistance. However, the use of an epoxy resin other than the silicone resin, a fluorine resin, or the like is not limited. . As the silicone resin, a known silicone resin as a resin for a sealing layer of a light emitting device is used without particular limitation.

  Moreover, the light obtained as the light-emitting device 1 can be appropriately adjusted to a desired emission color by mixing or dispersing a phosphor or the like in such a translucent resin. That is, by mixing and dispersing the phosphor in the resin constituting the sealing layer 8, the phosphor excited by the light emitted from the light emitting element 9 emits visible light, and the visible light and the light emitting element 9 The emitted light is mixed in color, so that the light emitting device 1 can obtain a desired light emission color. The type of the phosphor is not particularly limited, and is appropriately selected according to the type of light emitted from the light emitting element 9 and the target emission color.

  In the light emitting device of the first embodiment, the flow of the resin material constituting the sealing layer 8 is blocked by the blocking layer 7 made of translucent glass, and the resin material is placed on the mounting surface 21 of the base 2. Can be prevented from spreading to the outer region, so that a stable hemispherical lens-shaped sealing layer 8 can be formed. Further, since the blocking layer 7 is made of translucent glass, and the blocking layer 7 does not reflect or absorb the light transmitted through the sealing layer 8, the light emission efficiency is excellent and the light emission is high. A device is obtained.

  Next, a second embodiment of the light emitting device of the present invention will be described based on the drawings. FIG. 3A is a plan view of the light emitting device of the second embodiment as viewed from the upper surface (mounting surface) side, and FIG. 3B shows the light emitting device of FIG. It is sectional drawing cut | disconnected by. FIG. 3B shows a state in which the sealing layer made of resin is removed.

The light emitting device 1 according to the second embodiment is a light emitting device in which the electrical connection between the light emitting element 9 such as an LED element and the element connection terminal 4 is performed by wire bonding. That is, the two-wire type light emitting element 9 is disposed on the mounting portion 3 of the mounting surface 21 of the base body 2 and fixed using the silicone die bond material 10 that is an adhesive. A pair of electrodes of the light emitting element 9 are connected to predetermined element connection terminals 4 by bonding wires 11.
In the second embodiment, other configurations, materials, and the like are configured in the same manner as in the first embodiment, and thus description thereof is omitted.

  Also in the light emitting device of the second embodiment, as in the first embodiment, a stable hemispherical lens-shaped sealing layer 8 can be formed, and the damming layer 7 reflects light transmitted through the sealing layer 8. Or since it does not absorb, it is excellent in the light extraction efficiency.

Next, a method for manufacturing the light emitting device of the present invention will be described by taking an example of manufacturing the light emitting device shown in FIG. 1 having a base made of LTCC.
The light-emitting device 1 shown in FIG. 1 includes, for example, (A) a green sheet manufacturing process for a substrate, (B) a conductor paste layer forming process, (C) a glass paste layer forming process for damming, and (D) lamination shown below. After manufacturing the light emitting element substrate by the manufacturing method including the process and (E) firing step, this light emitting element substrate is used, and after (F) the light emitting element mounting step and then (G) the sealing layer forming step. Can be manufactured. 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 production process for substrate A green sheet (green sheet for substrate) for forming a substrate is produced using a glass ceramic composition containing glass powder and ceramic powder. The base green sheet includes an upper layer green sheet for forming an upper layer, an inner layer green sheet for forming an inner layer, and a lower layer green sheet for forming a lower layer.

  A green sheet for a substrate is prepared by adding a binder, and if necessary, a plasticizer, a dispersant, a solvent, etc. to a glass ceramic composition containing glass powder and ceramic powder. It can be manufactured by molding into a sheet and drying.

  As the glass powder for the substrate for producing the green sheet for the substrate, those having a glass transition point (Tg) of 550 ° C. or more and 700 ° C. or less are preferable. When Tg is less than 550 ° C., degreasing may be difficult, and when it exceeds 700 ° C., the shrinkage start temperature becomes high and the dimensional accuracy may be lowered. The glass powder is preferably one in which crystals precipitate when fired at 800 ° C. or higher and 930 ° C. or lower. If the crystal does not precipitate, sufficient mechanical strength may not be obtained.

Such base glass powder, as represented by mol% based on oxides, the _{SiO 2 57~65%, B 2 O} 3 and 13 to 18%, the CaO 9 to 23%, the _Al 2 _{O 3} 3 8%, those containing from 0.5 to 6% of at least one of them in total selected from _{K 2} O and Na ₂ O are preferred. By using a material having such a composition, the surface flatness of the substrate 2 can be easily improved.

Here, SiO ₂ serves as a glass network former. When the content of SiO ₂ is less than 57%, it is difficult to obtain a stable glass and the chemical durability may be lowered. On the other hand, when the content of SiO ₂ exceeds 65%, the glass melting temperature and Tg may be excessively increased. The content of SiO ₂ is preferably 58% or more, more preferably 59% or more, and particularly preferably 60% or more. Further, the content of SiO ₂ is preferably 64% or less, more preferably 63% or less.

B ₂ O ₃ is a glass network former. If the content of B ₂ O ₃ is less than 13%, there is a possibility that the glass melting temperature or Tg may be too high. On the other hand, when the content of B ₂ O ₃ exceeds 18%, it is difficult to obtain a stable glass, and the chemical durability may be lowered. The content of B ₂ O ₃ is preferably 14% or more, more preferably 15% or more. Further, the content of B ₂ O ₃ is preferably 17% or less, more preferably 16% or less.

Al ₂ O ₃ is added to increase the stability, chemical durability, and strength of the glass. If the content of Al ₂ O ₃ is less than 3%, the glass may become unstable. On the other hand, when the content of Al ₂ O ₃ exceeds 8%, the glass melting temperature and Tg may be excessively high. The content of Al ₂ O ₃ is preferably 4% or more, more preferably 5% or more. Further, the content of Al ₂ O ₃ is preferably 7% or less, more preferably 6% or less.

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

K ₂ O and Na ₂ O are added to lower Tg. When the total content of K ₂ O and Na ₂ O is less than 0.5%, the glass melting temperature and Tg may be excessively high. On the other hand, when the total content of K ₂ O and Na ₂ O exceeds 6%, chemical durability, particularly acid resistance may be lowered, and electrical insulation may be lowered. The total content of K ₂ O and Na ₂ O is preferably 0.8% or more and 5% or less.

  In addition, the glass powder for base | substrates is not necessarily limited to what consists only of the said component, Other components can be contained in the range with which various characteristics, such as Tg, are satisfy | filled. When other components are contained, the total content is preferably 10% or less.

  The glass powder for a substrate is obtained by producing glass having the above composition by a melting method and pulverizing it by a dry pulverization method or a wet pulverization method. In the case of the wet pulverization method, it is preferable to use water or ethyl alcohol as a solvent. Examples of the pulverizer include a roll mill, a ball mill, and a jet mill.

The 50% particle size (D ₅₀ ) of the glass powder for substrate is preferably 0.5 μm or more and 2 μm or less. If D ₅₀ of the glass powder is less than 0.5 [mu] m, handling the glass powder is likely to agglomerate are not only difficult, uniform dispersion becomes difficult. On the other hand, if the D ₅₀ of the glass powder exceeds 2μm, there is a possibility that increase and insufficient sintering of the glass softening temperature is generated. For example, the particle size may be adjusted by classification as necessary after pulverization.

  As the ceramic powder, those conventionally used for manufacturing LTCC substrates can be used. For example, alumina powder, zirconia powder, or a mixture of alumina powder and zirconia powder can be suitably used. In particular, it is preferable to use a ceramic powder having a higher refractive index than alumina (hereinafter referred to as a high refractive index ceramic powder) together with the alumina powder.

The high refractive index ceramic powder is a component for improving the reflectance of the base body 2 that is a sintered body, and examples thereof include titania powder, zirconia powder, and stabilized zirconia powder. While the refractive index of alumina is about 1.8, the refractive index of titania is about 2.7 and the refractive index of zirconia is about 2.2, which is higher than that of alumina. . The D ₅₀ of these ceramic powders is preferably 0.5 μm or more and 4 μm or less.

  By mixing and mixing such glass powder and ceramic powder such that the glass powder is 30% by mass to 50% by mass and the ceramic powder is 50% by mass to 70% by mass, glass ceramics are mixed. A composition is obtained. In addition, a slurry can be obtained by adding a binder and, if necessary, a plasticizer, a dispersant, a solvent, and the like to the glass ceramic composition.

  As the binder, for example, polyvinyl butyral, acrylic resin and the like can be suitably used. As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate and the like can be used. As the solvent, organic solvents such as toluene, xylene, 2-propanol and 2-butanol can be suitably used.

  The slurry thus obtained is formed into a sheet by a doctor blade method or the like, and dried to produce, for example, three base sheet green sheets (upper layer green sheet, lower layer green sheet and inner layer green sheet). To do. Further, via holes for interlayer connection are formed at predetermined positions of these green sheets for the substrate using a punching die or a punching machine, and holes for thermal vias are further formed as necessary.

(B) Conductive paste layer forming step By forming a conductive paste layer at a predetermined position of each base green sheet, the unfired element connection terminals 4 and the unfired external connection terminals 5 are formed. Further, the unfired connection via 6 is formed by filling the via hole with a conductive paste. Furthermore, an unfired thermal via is formed by filling a metal paste into the hole for the thermal via.

  Examples of the method for forming the conductor paste layer and the conductor paste filling layer include a method of applying or filling the conductor paste by screen printing. The film thickness of the formed conductive paste layer is adjusted so that the film thicknesses of the finally obtained element connection terminals 4, external connection terminals 5, and the like become predetermined film thicknesses. Moreover, as a formation method of a metal paste filling layer, the method of filling a metal paste by screen printing is mentioned.

  As the conductive paste used for forming the unfired element connection terminal 4, the unfired external connection terminal 5 and the unfired connection via 6, for example, a conductive metal powder mainly composed of copper, silver, gold or the like, ethyl cellulose or the like A vehicle and a paste formed by adding a solvent or the like as necessary can be used. In addition, as said conductor metal powder, the metal powder which consists of silver powder and silver and platinum or silver and palladium is used preferably. As the metal paste used for forming the unfired thermal via, a paste obtained by adding the above-described metal powder mainly composed of silver to a vehicle such as ethyl cellulose and, if necessary, a solvent or the like can be used.

(C) Damping glass paste layer forming step In the upper layer green sheet, the glass is surrounded so as to surround a region corresponding to the mounting portion 3 including a part of the unfired element connection terminal 4 formed in the step (B). The paste is screen-printed to form a damming glass paste layer 7 having an annular shape in plan view.

  As the glass paste, a paste obtained by adding a vehicle such as ethyl cellulose and, if necessary, a solvent or the like to the glass powder for the blocking layer described above is used. The thickness of the formed glass paste layer 7 for damming is preferably adjusted so that the height h of the finally obtained damming layer 7 is 10 μm or more and 50 μm or less. Moreover, the thickness of the glass paste layer 7 for damming can be made into the range of 10-50 micrometers by adjusting the fluidity | liquidity of a glass paste, or the number of processes of screen printing. Moreover, the width w of the pattern of the glass paste layer 7 for damming has the preferable range of 80-300 micrometers. By adjusting the width of the pattern of the screen printing plate, the width w of the pattern of the glass paste layer 7 for damming is preferably in the range of 80 to 300 μm.

(D) Lamination process The conductive paste layer-attached green sheet obtained in the step (B) and the conductor paste layer obtained in the step (C) and the green sheet with a damming glass paste layer in a predetermined order. After superimposing, they are integrated by thermocompression bonding. In this way, the unfired substrate 2 is obtained.

(E) Firing step About the unfired substrate 2 obtained in the step (D), after degreasing the binder or the like as necessary, firing is performed to sinter the glass ceramic composition and the like. To do.

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

  In addition, in the firing, the time can be appropriately adjusted in a temperature range of 800 ° C. to 930 ° C. in consideration of obtaining a dense structure of the base 2 and productivity. Specifically, it is preferable to hold at a temperature of 850 ° C. or more and 900 ° C. or less for 20 minutes or more and 60 minutes or less, and a temperature of 860 ° C. or more and 880 ° C. or less is particularly preferable. If the firing temperature is less than 800 ° C., the substrate 2 may not be obtained as a dense structure. On the other hand, if the firing temperature exceeds 930 ° C., the productivity and the like may be lowered due to deformation of the substrate 2. Further, when a metal paste containing a metal powder containing silver as a main component is used as the conductor paste, if the firing temperature exceeds 880 ° C., there is a risk that the predetermined shape cannot be maintained due to excessive softening. .

  Thus, a substrate for a light emitting element can be obtained. After firing, nickel plating, chrome plating, silver plating, nickel / silver plating are applied so as to cover the entire element connection terminal 4 and external connection terminal 5 as necessary. A conductive protective layer, such as gold plating, nickel / gold plating, etc., which is usually used for protecting a conductor in a light emitting element substrate, can be formed. Among these, nickel / gold plating is preferably used. For example, the nickel / gold plating can be formed by electrolytic plating using a nickel sulfamate bath for the nickel plating layer and a potassium gold cyanide bath for the nickel plating layer.

(F) Light-Emitting Element Mounting Step In the light-emitting element substrate obtained in the step (E), an LED element or the like having a pair of bump electrodes on the lower surface on the mounting portion 3 at the substantially central portion of the mounting surface 21 of the base 2. The light emitting element 9 is disposed, and is electrically connected to the element connection terminal 4 by metal-to-metal connection via solder, gold, gold-tin eutectic or the like.

(G) Sealing Layer Forming Step In this manner, a substantially hemispherical resin layer is formed by potting a fluid curable silicone resin material so as to cover the light emitting element 9 mounted on the mounting portion 3 of the substrate 2. And cured by heating or the like. In this way, a substantially hemispherical lens-shaped sealing layer 8 is formed in the inner region of the annular damming layer 7 made of glass formed on the mounting surface 21 of the substrate 2.

  In the manufacturing method of the light emitting device 1 described above, the number of the green sheets for the base used in the manufacturing process of the light emitting element substrate is not necessarily three, and may be two or four or more. Further, the order of forming each part can be appropriately changed as long as the light emitting element substrate can be manufactured. Furthermore, the substrate for a light emitting element may be manufactured by a method in which a multi-piece connection substrate is manufactured according to its size, and a step of dividing the substrate is obtained to manufacture individual substrates. In that case, the division timing may be before the light emitting element is mounted or after the light emitting element is mounted as long as it is after the firing.

  According to such a manufacturing method, the flow of the curable resin material for forming the sealing layer 8 is blocked by the blocking layer 7 made of glass, and the resin material is blocked on the mounting surface 21 of the base 2. Since wetting and spreading to the region outside the stop layer 7 is suppressed, a stable hemispherical lens-shaped resin sealing layer 8 is formed. Further, since the damming layer 7 is made of translucent glass and the damming layer 7 does not reflect or absorb the light transmitted through the sealing layer 8, the light emission is excellent in light extraction efficiency and has high emission luminance. A device is obtained.

  Examples of the present invention will be described below. In addition, this invention is not limited to an Example.

Examples 1-8
The light emitting device having the structure shown in FIG. 1 was manufactured by the following method.

<Preparation of glass paste for damming>
First, glass powder for a weir layer was manufactured. That is, the glass raw materials were prepared and mixed so that SiO ₂ was 81.6%, B ₂ O ₃ was 16.6%, and K ₂ O was 1.8% in terms of mol% in terms of oxide. This raw material mixture was put in a platinum crucible and melted at 1500 to 1600 ° C. for 60 minutes, and then the molten glass was poured out and cooled. The obtained glass was pulverized with an alumina ball mill for 20 to 60 hours to obtain a glass powder for a weir layer. In addition, ethyl alcohol was used as a solvent for pulverization.

  The 50% particle size (μm) of the obtained glass powder was measured using a laser diffraction / scattering particle size distribution analyzer (manufactured by Shimadzu Corporation, trade name: SALD2100), and it was 2.3 μm. Moreover, when the softening point of the glass powder was measured by using a differential thermal analyzer (Bruker AXS, trade name: TG-DTA2000), the temperature was increased to 1000 ° C. at a temperature increase rate of 10 ° C./min. It was 775 ° C.

  The glass powder obtained above and a resin component are blended at a mass ratio of 60:40, kneaded for 1 hour in a porcelain mortar, further dispersed three times with three rolls, and a glass paste for damming Got. In addition, the resin component used what prepared and disperse | distributed ethyl cellulose and alpha terpineol by mass ratio 85:15.

<Preparation of substrate for mounting light emitting element>
An upper layer green sheet, an inner layer green sheet, and a lower layer green sheet for manufacturing the substrate 2 of the light emitting device 1 were prepared.
First, in terms of oxide-based mol%, SiO ₂ is 60.4%, B ₂ O ₃ is 15.6%, Al ₂ O ₃ is 6%, CaO is 15%, K ₂ O is 1%, Na _The raw materials were blended and mixed so that ₂ O would be 2%. The raw material mixture was put in a platinum crucible and melted at 1600 ° C. for 60 minutes, and then the molten glass was poured out and cooled. This glass was pulverized with an alumina ball mill for 40 hours to produce a glass powder for a substrate. Note that ethyl alcohol was used as a solvent for grinding.

  35% by mass of the glass powder for the substrate, 40% by mass of alumina powder (manufactured by Showa Denko KK, trade name: AL-45H), zirconia powder (manufactured by Daiichi Rare Element Chemical Co., Ltd., trade name: HSY-3F-J) ) Was mixed so as to be 25% by mass, and mixed to produce a glass ceramic composition. 50 g of this glass ceramic composition, 15 g of an organic solvent (toluene, xylene, 2-propanol, 2-butanol mixed at a mass ratio of 4: 2: 2: 1), plasticizer (di-2-ethylhexyl phthalate) 2.5 g of polyvinyl butyral (trade name: PVK # 3000K, manufactured by Denka 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. .

  This slurry is applied on a PET film by a doctor blade method, dried green sheets are laminated, and the upper layer and the inner layer are flat and have a size after baking of 30 mm × 30 mm and a thickness of 0.35 mm. Green sheets for the lower layer and the lower layer were manufactured. Then, in each of the green sheets for the upper layer, the inner layer, and the lower layer, through holes for connecting vias having a diameter of 0.3 mm were formed at predetermined positions using a hole puncher. In this embodiment, a substrate for mounting light emitting elements is manufactured as a multi-piece connecting substrate, and is divided into one piece after firing, which will be described later, to form a substantially square light emitting element having an outer size of 30 mm × 30 mm. A mounting substrate (substrate) 1 was obtained. The following description will explain one section of the multi-piece connection board that becomes one light-emitting element mounting board after division.

  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 for 1 hour in a porcelain mortar, and further dispersed three times with three rolls to produce a conductor paste.

  The through-hole for connecting via formed in each of the green sheets was filled with the conductive paste obtained above by a screen printing method to form a connecting via paste layer. Thereafter, the element paste terminal paste layer was formed by screen printing the conductor paste on the connection via paste layer on the upper surface of the upper layer green sheet. Moreover, the paste layer for external connection terminals was formed by screen-printing the said paste for conductors on the connection via paste layer of the lower surface of the lower layer green sheet.

  Furthermore, the above-mentioned damming glass paste is formed so as to surround the mounting portion including a part of the element connection terminal paste layer on the upper surface of the upper green sheet on which the conductor paste layer is formed, that is, the mounting surface. Screen printing was performed to form a damming glass paste layer 7 having an annular shape in plan view (the diameter of the inner peripheral edge was 2.4 mm). Here, the width of the pattern of the printing plate at the time of screen printing was changed so that the width w of the damming layer 7 after firing had the dimensions described in Table 1. Further, the height h of the blocking layer 7 was set to the dimensions described in Table 1 by changing the number of times of screen printing. In addition, the width w and height h of the blocking layer were measured with a contact-type film thickness meter (manufactured by Tokyo Seimitsu Co., Ltd., trade name: Surfcom 1400D).

  Next, the green sheet for the upper layer with the conductive paste layer and the glass paste layer, the green sheet for the inner layer with the conductive paste layer, and the green sheet for the lower layer with the conductive paste layer thus obtained were laminated to obtain an unsintered connection substrate. A dividing line (cut line) in which each section has an outer size of 3 mm × 3 mm after firing is put on this unfired connection substrate, and then degreased by holding at 550 ° C. for 5 hours, and further at 870 ° C. for 30 The substrate was fired by holding for a few minutes to produce a multi-piece connected substrate. The obtained multi-piece connection substrate was divided along a dividing line to manufacture a substrate for mounting a light emitting element.

<Mounting and sealing of light emitting element>
Next, an LED element (product name: DA350, manufactured by CREE, Inc.) 9 having a pair of electrodes on the lower surface is arranged on the mounting portion of the substrate for mounting the light emitting element thus obtained, and the pair of electrodes is connected to the element. The connection terminal 4 was connected by gold tin solder bonding. Thereafter, a curable silicone resin material (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KER-6075) is dispensed to the inner region of the blocking layer 7 formed on the mounting surface 21 in the firing step. A coating layer covering the LED element was formed by injecting using a product name, ML-5000XII). The coating layer thus formed was heated at 100 ° C. for 1 hour and then cured by heating at 150 ° C. for 3 hours to form a translucent sealing layer 8.

<Measurement and evaluation of each part of light emitting device>
The height H to the top of the sealing layer 8 thus formed was measured using a contact-type film thickness meter (trade name: Surfcom 1400D, manufactured by Tokyo Seimitsu Co., Ltd.), and the diameter D of the bottom was measured using a length measuring microscope ( It measured using the Olympus make, brand name: STM6). The measurement results are shown in Table 1 together with the width w and height h of the blocking layer.

  As is apparent from Table 1, in the light emitting devices of Examples 2 to 8 having the blocking layer 7 having a height h of 10 to 30 μm and a width w of 80 to 200 μm, the curable silicone resin material is the blocking layer 7. The height H to the top of the sealing layer 8 is ½ of the diameter D of the bottom. That is, it can be seen that the sealing layer 8 having a hemispherical lens shape is formed. By forming the sealing layer 8 having such a hemispherical lens shape, the path lengths through which the light emitted from the light emitting element 9 passes through the sealing layer 8 are equal in all directions, and stable and good optical characteristics are obtained. A light emitting device having the following can be obtained.

  On the other hand, in Example 1, the height h of the blocking layer 7 is 10 μm or less, and the blocking layer 7 cannot sufficiently suppress wetting and spreading to the outside of the curable silicone resin material. . Therefore, not only the diameter D of the bottom of the sealing layer 8 is larger than the diameter (24 mm) of the inner peripheral edge of the blocking layer 7, but also the height H of the sealing layer 8 is much more than 1/2 of the diameter D of the bottom. It is getting smaller. Therefore, it can be seen that the stable hemispherical lens-shaped sealing layer 8 is not formed so that the path lengths of transmitted light are equal in all directions.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device, 2 ... Base | substrate, 3 ... Mounting part, 4 ... Element connection terminal, 5 ... External electrode terminal, 6 ... Connection via, 7 ... Damping layer, 8 ... Sealing layer, 9 ... Light-emitting element, 11 ... Bonding wire, 21... Mounting surface, 22.

Claims (6)

A substrate made of an inorganic insulating material and having a mounting surface, a part of which is a mounting portion on which a light emitting element is mounted;
An element connection terminal formed on the mounting surface of the base;
A damming layer made of translucent glass formed on the mounting surface of the base so as to surround the mounting portion;
A light emitting element mounted on the mounting portion of the base body and electrically connected to the element connection terminal;
And a sealing layer made of a resin provided so as to cover the light emitting element in a region inside the damming layer.   The light emitting device according to claim 1, wherein a thermal expansion coefficient of the damming layer is smaller than a thermal expansion coefficient of the base.   3. The light emitting device according to claim 1, wherein the damming layer has an annular planar shape, has a height of 10 to 50 μm, and a width of 80 to 300 μm.   The light emitting device according to claim 1, wherein the sealing layer has a substantially hemispherical three-dimensional shape.   The light emitting device according to claim 1, wherein the sealing layer is a layer formed by potting a curable resin material having fluidity. A base made of an inorganic insulating material, part of which has a mounting surface serving as a mounting portion on which a light emitting element is mounted, an element connection terminal formed on the mounting surface of the base, and a mounting surface of the base Producing a light emitting element substrate having a damming layer made of translucent glass formed so as to surround the mounting portion;
Mounting a light emitting element on the mounting portion of the base of the light emitting element substrate, and electrically connecting the light emitting element to the element connection terminal;
Forming a sealing layer made of a resin covering the light emitting element by potting and curing a curable resin material having fluidity in a region inside the blocking layer on the mounting surface of the base body; A method for manufacturing a light-emitting device.

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