JP5125060B2 - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high performance and highly reliable light-emitting device by achieving both effects, i.e., enhancement of light intensity and high precision mounting of a light-emitting element without alignment deviation as to the trade-off relation between the reduction of light loss caused by an insulating substrate and the prevention of alignment deviation. <P>SOLUTION: This light-emitting device comprises a light-emitting element 3 having a metal film formed on its bottom, and a metal member 2 on which the light-emitting element 3 is mounted and which surrounds the periphery of the light-emitting element 3. The metal member 2 and the metal film of the light emitting element 3 are bonded together with a die bond member consisting of metal. A region (exposure region) 1b having wettability to the die bond member lower than that to the bonding region of the die bond member is arranged under the light-emitting element 3 and in the periphery of the die bond member. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a light emitting device, and more particularly to a light emitting device in which a light emitting element is formed by die bonding to a metal member.

  Conventionally, there has been proposed a light emitting device in which a light emitting element is die-bonded to a die pad portion made of a metal member that covers the surface of an insulating substrate and is embedded in a package (sealing member). In this light emitting device, when die bonding is performed on the die pad portion formed on the surface of the insulating substrate, an appropriate amount of a heat-meltable die bond member such as solder paste is applied to the surface of the die pad portion. It is manufactured by a method in which a light emitting element is placed on a member and the die bonding member is reflowed and then solidified (for example, Patent Document 1).

  In this manufacturing method, the die pad portion in the insulating substrate is 0.50 to 1.50 times the length and width of the rectangular light-emitting element to be die-bonded, whereby the surface of the die bond member is reflowed. Due to the self-alignment effect due to tension, the light emitting element is accurately arranged at the center of the die pad portion.

JP 2003-264267 A

  However, if the size of the die pad portion in the insulating substrate is only 0.50 to 1.50 times the size of the light emitting device, the light emitting device cannot be accurately placed at the center of the die pad portion. The exact requirement for misalignment cannot be fully satisfied. Moreover, even if it can arrange | position correctly to some extent, the new subject that the light loss of light-emitting device itself cannot be avoided arises.

  That is, when the dimension of the die pad portion is set to be substantially equal to or smaller than the dimension of the light emitting element, the surface tension of the die bonding member works well, and the light emitting element can be accurately arranged at an appropriate place. However, since the light emitting element is usually placed on an insulating substrate with low reflectivity, if the size of the die pad is almost the same as the dimension of the light emitting element, the light emitting element is emitted from the side surface of the light emitting element toward the periphery of the light emitting element. Light is absorbed / transmitted by the insulating substrate, and the light intensity of the light emitting device is greatly impaired.

  Further, in order to prevent a decrease in light emission intensity, it is necessary to form a separate metal film on the outer periphery of the die pad portion. However, even in this case, since the metal film does not cause misalignment, it is necessary to form the metal film separately from the die pad portion. Again, avoid light loss in this separated region (region where the insulating substrate is exposed). I can't.

  Further, in order to prevent absorption of light emitted from the light emitting element, it is conceivable to form a metal film on the entire back surface (that is, die bond surface) of the light emitting element. However, when the metal film is formed on the entire back surface of the light emitting element, the difference in alignment between the size of the die pad portion and the size of the metal film occurs due to the surface tension of the die bonding member, and the die pad portion is centered. It cannot be placed accurately.

In addition, when the size of the die pad portion is larger than the size of the light emitting element, the light from the light emitting element can be reflected by the die pad portion around the light emitting element, thereby preventing the light intensity of the light emitting device from decreasing. However, on the other hand, the light emitting element moves within the die pad portion, resulting in a difference in alignment between the size of the light emitting element and the size of the die pad portion.
This misalignment of the light emitting elements causes color misregistration, color unevenness, and the like of the light emitting device, and is not satisfactory particularly in the current situation where there is an increasing demand for improving color unevenness for the light emitting device in recent years. .

  The present invention has been made in view of the above-described problems. The trade-off relationship between reduction of light loss due to an insulating substrate and prevention of misalignment is achieved. It is an object to provide a high-performance and highly reliable light-emitting device by realizing both effects of accurate mounting.

According to the light emitting device of the present invention,
A light emitting device having a metal film formed on the bottom;
A metal member on which the light emitting element is mounted and disposed from the lower part of the light emitting element to the periphery thereof;
A die-bonding member made of a metal that bonds the metal member and the metal film of the light-emitting element;
The die bond is located below the light emitting element, starting from the peripheral edge of the metal film on the bottom surface of the light emitting element and extending toward the inside of the light emitting element , and at the periphery of the die bond member rather than the metal member. A region having poor wettability with respect to the member is arranged, or
A substrate,
A metal member formed on the substrate;
A light emitting device having a metal film formed on the bottom;
A light-emitting device comprising a die-bonding member made of a metal that bonds the metal member and a metal film of the light-emitting element,
A part of the substrate is exposed from the metal member so as to start from the periphery of the metal film on the bottom surface of the light emitting element and spread toward the inside of the light emitting element. To do.
In these light emitting devices,
It is preferable that the metal member is formed on a substrate, and a part of the substrate is exposed in the poor wettability region.
The metal film is preferably formed on the entire bottom surface of the light emitting element.
The poor wettability region is preferably formed as two or more separate regions.
The region having poor wettability is preferably arranged with a size of 1 to 20% of the size of the metal film.
The region formed by exposing a part of the substrate formed below the light emitting element is preferably formed as two or more separate regions.
The metal film is preferably an electrode of the light emitting element.
It is preferable that the metal film has a reflectance of 70% or more with respect to light emitted from the light emitting element.
The metal member and / or metal film preferably has a contact angle with the die bond member of 45 ° or less.
The region where a part of the substrate is exposed is preferably arranged with a size of 1 to 20% of the size of the metal film.

  According to the light-emitting device of the present invention, both the effects of improving the light intensity and mounting the light-emitting element with high accuracy are realized with respect to the trade-off relationship between the reduction of the optical loss due to the insulating substrate and the prevention of the alignment shift. can do. As a result, a high-performance and highly reliable light-emitting device can be obtained.

  The light-emitting device of the present invention includes a light-emitting element and a metal member, a metal film is formed on the bottom of the light-emitting element, and the light-emitting element and the metal member are bonded by a die bond member. The metal member is usually formed on the substrate.

(Light emitting element)
The light emitting element may be a semiconductor light emitting element, and any element may be used as long as it is an element called a light emitting diode. For example, a laminated structure including an active layer is formed on a substrate by various semiconductors such as a nitride semiconductor such as InN, AlN, GaN, InGaN, AlGaN, InGaAlN, a III-V compound semiconductor, and a II-VI compound semiconductor. What was formed is mentioned. As a substrate, an insulating substrate such as sapphire or spinel (MgA1 ₂ O ₄ ) whose main surface is any one of C-plane, A-plane and R-plane, silicon carbide (6H, 4H, 3C), silicon, ZnS ZnO, GaAs, diamond; oxide substrates such as lithium niobate and neodymium gallate, nitride semiconductor substrates (GaN, AlN, etc.), and the like. Examples of the semiconductor structure include a homostructure such as a MIS junction, a PIN junction, and a PN junction, a hetero bond, and a double hetero bond. Alternatively, the semiconductor active layer may have a single quantum well structure or a multiple quantum well structure in which a thin film in which a quantum effect is generated is formed. The active layer may be doped with donor impurities such as Si and Ge and / or acceptor impurities such as Zn and Mg. The emission wavelength of the resulting light-emitting element can be changed from the ultraviolet region to red by changing the semiconductor material, the mixed crystal ratio, the In content of InGaN in the active layer, the type of impurities doped in the active layer, etc. .

The shape of the light emitting element is not particularly limited. For example, it is suitable that the light emitting element has a circular shape, an elliptical shape, a polygonal shape or a shape close thereto, and in particular, a rectangular shape, a rectangular shape, a square shape, or a shape similar thereto. Is more preferable.
Such a light emitting device may be a single-sided electrode in which an n-electrode and a p-electrode are formed on the same side with respect to the substrate, or a double-sided electrode in which the n-electrode or p-electrode is formed on the back surface of the substrate It may be.

(Metal film)
A metal film is formed on the entire bottom surface of the light emitting element (die bonding surface of the light emitting element). In particular, the metal film is preferably polygonal or formed on the entire back surface of the light emitting element. Thereby, since the wettability on the light emitting element side is increased, the self-alignment effect can be efficiently exhibited. The metal film preferably has a reflectance of 70% or more, more preferably 80% or more, with respect to light emitted from the light emitting element. When the electrode is formed on the back surface of the substrate, the metal film is preferably formed on the electrode. However, the electrode and / or the metal film may have both functions.

The metal film can be formed of, for example, a single layer film or a laminated film such as Al, Ag, Au, and Pd. As a method for forming the metal film, various known methods such as vapor deposition, sputtering, and plating can be used.
In addition, it is preferable that the barrier layer which prevents the spreading | diffusion of the die-bonding member mentioned later is formed in the surface (namely, surface on the die-bonding side) of a metal film. The barrier layer can be formed of, for example, a single-layer film or a laminated film of a refractory metal such as Mo, W, or Rh. As a method for forming the barrier layer, various known methods such as vapor deposition, sputtering, and plating can be used.
The metal film is preferably a material having a contact angle with the die bond member of about 90 ° or less, about 80 ° or less, about 60 ° or less, and further about 45 ° or less. From another point of view, it is preferable that the contact angle of the die-bonding member to a region having poor wettability (for example, the substrate surface) described later is about 10 ° smaller, about 20 ° smaller, or about 30 ° smaller. As a result, the die bond member infiltrates into a region that is more easily wetted, and the light emitting element can be easily aligned in a desired region. In this specification, the contact angle was measured by a sessile drop method at a melting point of the bonding material +40 to 50 ° C. (“Wetting of graphite by molten magnesium”, “Light metal” Vol. 55, No. 7 (2005) p310). -314) refers to the value.

(Metal member)
The metal member is usually used as a die pad portion for mounting and fixing the light emitting element. Moreover, the metal member is arrange | positioned from the lower part of the light emitting element to the peripheral part. The metal member is preferably arranged on the substrate so as to cover the substrate surface. The metal member does not necessarily have to cover the entire surface of the substrate, but includes 120% or more, 130% or more, 150% of the area occupied by the light emitting element including the region where the light emitting element is die-bonded and its peripheral part. The above region is preferably covered. Thereby, the light radiate | emitted from a light emitting element can be utilized effectively. In this case, the metal member is preferably arranged continuously or partially continuously from directly below the light emitting element to the periphery thereof. In addition, it is preferable that the light emitting elements are arranged almost uniformly without being unevenly distributed. Furthermore, it is more preferable that the metal member extends from the outside of the light emitting element to at least directly below the peripheral edge of the light emitting element.

The material of the metal member is not particularly limited. However, in order to effectively use light emitted from the element, for example, about 70% or more, preferably about 80% or more, about 85% with respect to light emitted from the light emitting element. As described above, those having a reflectance of about 90% or more are suitable. Further, a material having a higher reflectance than a region having poor wettability described later is suitable.
In order to obtain a self-alignment effect, the metal member is preferably a material having a contact angle with the die bond member of about 90 ° or less, about 80 ° or less, about 60 ° or less, and further about 45 ° or less. From another point of view, it is preferable that the contact angle of the die-bonding member to a region having poor wettability (for example, the substrate surface) described later is about 10 ° smaller, about 20 ° smaller, or about 30 ° smaller.

  Further, a material having a relatively large mechanical strength or a material that can be easily punched or etched or etched is preferable. For example, it can be formed of a single layer film or a laminated film of Al, Ag, Au, Pd or the like. When the metal member is formed in a film shape on the substrate, various known methods such as vapor deposition, sputtering, plating, etc. can be used.

Usually, in a light emitting device, a metal lead electrode electrically connected to the light emitting element is embedded in a sealing member (sealing resin) described later together with the light emitting element and the like, but the metal member is used as the lead electrode. You can also
When the metal member and the light emitting element are connected by wire bonding using a wire, the wire has a good ohmic property with the electrode of the light emitting element, a good mechanical connectivity, or an electric conduction It is preferable that the property and heat conductivity are favorable. The thermal conductivity, preferably ^{0.01cal / S · cm 2 · ℃} / than about cm further ^{0.5cal / S · cm 2 · ℃} / cm or higher order is more preferable. Considering workability and the like, the diameter of the wire is preferably about 10 μm to 45 μm. Examples of such wires include metals such as gold, copper, platinum, and aluminum, and alloys thereof.

(Die bond member)
The die bond member is a bonding member that is used to mount and fix the metal film of the light emitting element on the metal member so as to face the metal member described later. For example, materials such as SnPb-based, SnAgCu-based, AuSn-based, SnZn-based, and SuCu-based materials can be preferably used. Among these, AuSn eutectic is preferable. Optionally, Bi, In or the like may be added to these for the purpose of improving wettability or solder cracking property. Note that the die-bonding member is usually disposed directly under the light-emitting element and is not disposed so as to extend to the peripheral portion of the light-emitting element, and is preferably not disposed in such a region. In the present invention, it may extend to a part of the periphery of the light emitting element to the extent that it can be ignored with respect to the alignment effect.

(Area with poor wettability)
In the present invention, the light-emitting element is usually die-bonded on the metal member by the die-bonding member. However, the light-emitting element is below the light-emitting element and in the periphery of the die-bonding member with respect to the die-bonding member rather than the bonding region of the die-bonding member. And areas with poor wettability are placed. In this specification, the region having poor wettability refers to a region where the contact angle with the die bond member exceeds 90 °. The region having poor wettability is preferably a material having a contact angle of 100 °, 105 °, 110 ° or more. Such a region with poor wettability may be formed of any material or state. For example, this region may be a thin film or the like formed on the metal member, but is preferably disposed by exposing a part of the substrate or the like under the metal member. Accordingly, since the region having poor wettability can be disposed at a position lower than the portion where the die bonding member is disposed, the light emitting element easily moves when the peripheral height is low, and the light emitting element self Alignment is easy.
The position of this region is not particularly limited as long as it is arranged in the periphery of the die bond member, but it is inside from the peripheral portion of the metal film of the light emitting element (in other words, the center side of the light emitting element, directly below the light emitting element). It is preferable that the region corresponds to. More specifically, it is preferably a region having a predetermined width inward from the peripheral edge of the metal film. However, it does not need to be uniformly arranged in the entire peripheral part of the die bond member, and may not be arranged in a part of the peripheral part as described later. In addition, in order to reduce the area of the poorly wettable region that causes the optical loss while maintaining the self-alignment effect, this region is separated in the region corresponding to the inner side from the peripheral portion of the metal film. These regions are suitable, and are preferably configured by arranging two pairs of regions facing each other. Here, a pair of regions facing each other means a region along an opposing arc or each side having a shape of a metal film provided in the light emitting element or a shape similar to the shape. In addition, the arrangement of two sets means that there are at least two sets of regions along each side. Furthermore, this region is preferably formed symmetrically with respect to the center line of the metal film. Thereby, the self-alignment effect can be exhibited more.

  Specifically, as will be described later, the two pairs of regions facing each other are, as will be described later, four regions along each side, that is, parallel to each side when the metal film of the light-emitting element is a quadrangle ( In the case of a hexagon, it means four regions (see FIG. 4E) along at least four sides facing each other among the six sides. Each region may be, for example, a circle, an ellipse, a polygon, or any shape that approximates this. However, the regions are not necessarily completely independent / separated regions, and two or more of two pairs of regions, that is, four regions may be integrally connected (FIG. 1B to ( d)). In particular, as shown in FIG. 1A, in this region, the metal film has a quadrangular shape, in particular, a rectangular shape, and a rectangular shape having a predetermined width from the peripheral portion in parallel to the periphery of the metal film. In particular, it is preferable that the rectangular regions form a pair of independent regions facing each other in parallel, and two pairs of independent regions are formed independently.

Each independent region is preferably formed at the center of each side of the peripheral portion of the metal film. The width of this region is suitably such that the die bond members are not connected to each other beyond this region during normal die bonding. For example, the width is about 20 to 200 μm. From another point of view, the width of the metal film is about 5 to 20%, and the length is preferably about 20 to 90% of the length of the metal film, and more preferably about 20 to 80%.
In addition, when two pairs of regions are formed of two or more regions, each region may have a different area, but is formed by four regions having the same size and / or the same shape. It is preferable that Specifically, it is suitable that the four regions each have an area of about 1 to 20% of the metal film. From another viewpoint, when it is formed of two or more regions, the total area of this region is preferably 4 to 80% of the metal film.

(substrate)
The substrate is a substrate for mounting and fixing the light emitting element, and is preferably formed of an appropriate material in order to ensure insulation. Specific examples include ceramics such as Al ₂ O ₃ and AlN, plastics such as high melting point nylon, and glass. Especially, it is suitable for the material that a contact angle with a die-bonding member exceeds 90 degrees, and it is more preferable that it is a material more than 100 degrees, 105 degrees, and 110 degrees. By selecting such a material, the alignment effect of the die bonding member at the time of die bonding of the light emitting element can be more remarkably exhibited.

(Other parts)
(Sealing member)
The sealing member is formed of any material as long as the above-described light emitting element or the like is preferably sealed integrally or in a lump shape, and insulation can be ensured with respect to the light emitting element or the like. May be. Examples thereof include polyphthalamide (PPA), polycarbonate resin, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), ABS resin, epoxy resin, phenol resin, acrylic resin, PBT resin, and the like, ceramic, glass, and the like. Among these, a translucent resin is preferable. In these materials, various dyes or pigments may be mixed and used as a colorant. For _{example, Cr 2 O 3, MnO 2} , Fe 2 O 3, carbon black and the like. Note that the light-transmitting property means a property of transmitting light emitted from the light emitting element to about 70% or more, about 80% or more, about 90% or more, or about 95% or more.
The size and shape of the sealing member are not particularly limited, and may be any shape such as a cylinder, an elliptical column, a sphere, an oval, a triangular column, a quadrangular column, a polygonal column, or a shape similar to these, A lens for condensing light may be integrally formed.

The sealing member may contain a diffusing agent or a fluorescent material. The diffusing agent diffuses light and can reduce the directivity from the light emitting element and increase the viewing angle. The fluorescent substance converts light from the light emitting element, and can convert the wavelength of light emitted from the light emitting element to the outside of the sealing member. When the light from the light-emitting element is high-energy short-wavelength visible light, nitrogen-containing CaO—Al ₂ O activated with a perylene derivative, ZnCdS: Cu, YAG: Ce, Eu and / or Cr, which is an organic fluorescent material Various inorganic phosphors such as _3- SiO ₂ are suitably used. In the present invention, when white light is obtained, in particular, when a YAG: Ce fluorescent material is used, light from the blue light emitting element and a yellow color which is a complementary color by partially absorbing the light can be emitted depending on the content. The system can be formed relatively easily and reliably. Similarly, when a nitrogen-containing CaO—Al ₂ O ₃ —SiO ₂ fluorescent material activated by Eu and / or Cr is used, the light from the blue light emitting element and a part of the light are absorbed depending on the content. Thus, a red color which is a complementary color can emit light, and a white color can be formed relatively easily and with high reliability. In addition to these fluorescent materials, any of the known fluorescent materials described in, for example, Japanese Patent Application Laid-Open Nos. 2005-19646 and 2005-8844 can be used.

(Other parts)
The light-emitting device of the present invention is attached to the surface of the sealing member as a part of the light-emitting device, for example, a lens made of plastic or glass at the light emitting portion of the light-emitting element (for example, above the light-emitting element) May be provided. In order to efficiently extract light from the light emitting element, various components such as a reflection member, an antireflection member, and a light diffusion member may be provided. Further, a protective element for improving electrostatic withstand voltage may be provided.

The light-emitting device of the present invention is formed as a surface-mount (SMD) light-emitting device in which a light-emitting element and a sealing resin are disposed in a recess of a package having a bottom surface and a wall portion surrounding the light-emitting element. Also good. The package may be formed of any material as long as it can protect the light emitting element, the sealing resin, and the like. Especially, it is preferable that it is a material which has insulation and light-shielding properties, such as a ceramic and milky white resin. Further, it is preferable to select a package having a small difference in thermal expansion coefficient with respect to the sealing resin or the like when affected by the heat generated from the light emitting element or the like. . The bottom surface and the wall of the package may be made of a material that is continuous with the substrate and the metal member, and a part of the metal member may be exposed to form an electrical connection or a heat dissipation path. A reflective material that reflects light from the light emitting element may be provided inside the package, or may be formed in a reflector shape for condensing light.
Embodiments of the light emitting device according to the present invention will be described below in detail with reference to the drawings.

Example 1
As shown in FIGS. 2A and 2B, the light emitting device of this embodiment has a package 1 made of Al ₂ O ₃ having a recess 1a formed on the surface thereof, and 1a insulation that is the bottom surface of the recess. A metal member 2, 2a made of Ag covering a part of the upper surface of the substrate and the insulating substrate 1, positive and negative electrodes 5 on the surface, and an Al metal film (not shown) formed on the entire back surface. The light emitting element 3 is provided.
In the metal member 2 in the recess, an exposed region 1b where the insulating substrate 1 is partially exposed is formed as a region with poor wettability. The exposed region 1 b is disposed inside the light emitting element 3 from directly below the peripheral edge 3 a of the metal film formed on the light emitting element 3.

This light emitting device can be manufactured as follows.
First, a square light-emitting element 3 having a length of 800 μm and a width of 800 μm is prepared.
The light emitting element 3 is made of a nitride semiconductor that emits blue light, and emits light having a wavelength of 465 nm. Positive and negative electrodes 5 are respectively formed on the surface of the light emitting element 3. On the back surface, an Al metal film, a W barrier film for preventing diffusion of the solder material, and a Pt film wetted by the solder are laminated in this order on the entire surface by sputtering.

Next, an Al ₂ O ₃ substrate (the reflectance of light having a wavelength of 465 nm is approximately 70%) having a length of 3.0 mm, a width of 3.0 mm, and a thickness of 1.0 mm is prepared as the insulating substrate 1. A cylindrical recess 1a having a diameter of 2.5 mm and a depth of 0.6 mm is formed in the center of the insulating substrate 1.

A W film is formed on a part of the upper surface of the insulating substrate 1 and the bottom surface of the recess 1a by a printing method. After the W film is sintered, Ag plating with a film thickness of about 7 μm is performed. The metal members 2 and 2a to be formed are formed. This metal member has a reflectance of about 95% for light having a wavelength of 465 nm.
The metal member 2 formed on the bottom surface of the recess 1a includes a die pad, reflection of light emitted toward the insulating substrate 1 during LED light emission, and a wire bond pad connected to one (for example, negative) electrode of the light emitting element 3. It also has three functions. The die pad function is mainly performed by the metal member 2 in a region corresponding to the size of the light emitting element 3, and the reflection function and the wire bond pad function are performed by the metal member 2 in the outer peripheral portion of the light emitting element 3.
Further, the metal member 2 a on the upper surface of the insulating substrate 1 fulfills a wire bond pad function for connecting to the other (for example, positive) electrode of the light emitting element 3.

On the metal member 2 on the bottom surface of the recess 1a, an exposed region 1b for exposing the Al ₂ O ₃ as the insulating substrate 1 is formed. The exposed region 1b is arranged as a region extending from the peripheral edge 3a of the light emitting element 3 (strictly speaking, the metal film on the back surface of the light emitting element 3) to the inside of the light emitting element 3, and is a rectangular region having a width of 50 μm and a length of 600 μm, respectively. It is. A total of four exposed regions 1b are independently arranged at the center of each side of the peripheral edge 3a of the light emitting element 3.

  Subsequently, on the metal member 2 corresponding to the die pad, an appropriate amount of 80 wt% Au, a paste made of Au—Su particles and a flux is applied as a die bond member (not shown), and the light emitting element 3 is mounted thereon. And temporarily fix.

Thereafter, in order to align the light emitting element 3 with high accuracy in a predetermined region, the insulating substrate 1 on which the light emitting element 3 is temporarily fixed is passed through a reflow furnace at 340 ° C. to volatilize the flux as the paste solvent, and Au -Sn is melted, further solidified, and bonded and bonded to a region corresponding to the die pad of the metal member 2.
Thereafter, the flux is washed with a semi-aqueous detergent.

Next, the wires 4 are wired between the positive and negative electrodes on the upper surface of the light emitting element 3 and the wire bond pads corresponding to the respective electrodes.
Subsequently, as a translucent coating material (not shown), a silicone resin containing a fluorescent material is formed on the main light extraction surface and side surfaces of the light emitting element 3.

The variation in mounting accuracy of the light emitting device thus obtained was measured and found to be 30 μm at 4σ. Further, when the luminous flux was measured when driven at 350 mW, it was about 45 lm.
From this result, in the light emitting device of this example, when the light emitting element is mounted, the metal member 2 functioning as a die pad and the exposed area of the insulating substrate which is a poorly wettable area where the mounting position of the light emitting element 3 can be strictly controlled. Since the self-alignment effect is sufficiently exhibited by 1b, the mounting accuracy can be remarkably improved. Accordingly, when the light emitting element 3 emits light, the light radiated in the direction of the insulating substrate 1 can be efficiently reflected by the metal member 2 existing on the outer peripheral portion of the light emitting element 3, so that the light extraction efficiency is improved. Can do.

Comparative Example 1
As Comparative Example 1, as shown in FIGS. 3A and 3B, the shape of the metal member 12 formed on the bottom surface of the recess 1a of the insulating substrate 1 is substantially the same as the shape of the light emitting element 3, except that the shape is substantially the same. A light emitting device having the same structure as in Example 1 was formed. In this light emitting device, the insulating substrate is exposed at the bottom surface of the recess 1a where the metal member 12 is not formed.

In this light emitting device, the metal member 12 does not have the reflection function in the first embodiment.
Therefore, when this light-emitting device is manufactured, although the self-alignment effect is obtained, the loss of light emitted toward the insulating substrate 1 is larger when the light-emitting element 3 emits light than in Example 1. The luminous flux in this case was measured in the same manner as in Example 1. As a result, it was about 36 lm, and an optical loss of about 20% occurred from the light emitting device of Example 1.
Further, when the mounting variation was measured in the same manner as in Example 1, it was about 50 to 70 μm at 4σ.

Comparative Example 2
As Comparative Example 2, as shown in FIGS. 4A and 4B, the shape of the metal member 22 formed on the bottom surface of the recess 1a of the insulating substrate 1 is the same as the size of the light emitting element 3, and A light emitting device having a structure substantially similar to that of Example 1 was formed except that the metal film 23 was formed on the outer peripheral portion so as to be separated from the metal member 22 by 50 μm.

In this light emitting device, the surface of the insulating substrate 1 is exposed between the metal member 22 functioning as a die pad portion and the metal film 23.
Therefore, when manufacturing this light-emitting device, a self-alignment effect can be obtained. Compared with Comparative Example 1, the loss of light emitted toward the insulating substrate 1 when the light-emitting element 3 emits light due to the effect of the metal film 23. Is alleviated. However, when the luminous flux of this light-emitting device was measured, it was about 40 lm, and about 10% of the light loss was generated from the light-emitting device of Example 1.
Further, when the mounting variation was measured in the same manner as in Example 1, it was about 50 to 70 μm at 4σ.

  It can be used for various light sources such as illumination light sources, various indicator light sources, in-vehicle light sources, display light sources, liquid crystal backlight light sources, traffic lights, in-vehicle components, and signboard channel letters.

It is a schematic plan view of the principal part for demonstrating the area | region where the wettability in the light-emitting device of this invention is bad. It is the schematic exploded view and perspective view which show the principal part of the light-emitting device of this invention. It is the schematic exploded view and perspective view which show the principal part of the light-emitting device for a comparison. It is the schematic exploded view and perspective view which show the principal part of another light-emitting device for a comparison.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light-emitting device 1 Insulating substrate 1a Recessed part 1b, 11b, 21b, 31b, 41b Exposed area | region 2, 2a Metal member 3 Light emitting element 3a Peripheral part 4 Wire 5 Electrode

Claims (11)

A light emitting device having a metal film formed on the bottom;
A metal member on which the light emitting element is mounted and disposed from the lower part of the light emitting element to the periphery thereof;
A die-bonding member made of a metal that bonds the metal member and the metal film of the light-emitting element;
The die bond is located below the light emitting element, starting from the peripheral edge of the metal film on the bottom surface of the light emitting element and extending toward the inside of the light emitting element , and at the periphery of the die bond member rather than the metal member. An area having poor wettability with respect to a member is disposed.   The light-emitting device according to claim 1, wherein the metal member is formed on a substrate, and a portion of the substrate is exposed in the poor wettability region.   The light emitting device according to claim 1, wherein the metal film is formed on the entire bottom surface of the light emitting element.   The light emitting device according to claim 1, wherein the poor wettability region is formed as two or more separate regions.   The light emitting device according to any one of claims 1 to 4, wherein the region having poor wettability is arranged in a size of 1 to 20% of a size of the metal film. A substrate,
A metal member formed on the substrate;
A light emitting device having a metal film formed on the bottom;
A light-emitting device comprising a die-bonding member made of a metal that bonds the metal member and a metal film of the light-emitting element,
A part of the substrate is exposed from the metal member so as to start from the peripheral portion of the metal film on the bottom surface of the light emitting element and toward the inside of the light emitting element. Light-emitting device.   The light-emitting device according to claim 6, wherein a region formed by exposing a part of the substrate formed below the light-emitting element is formed as two or more separate regions.   The light emitting device according to claim 1, wherein the metal film serves as an electrode of the light emitting element.   The light emitting device according to claim 1, wherein the metal film has a reflectance of 70% or more with respect to light emitted from the light emitting element.   The light emitting device according to claim 1, wherein the metal member and / or the metal film has a contact angle with the die bond member of 45 ° or less.   The light emitting device according to claim 6 or 7, wherein a region where a part of the substrate is exposed is arranged in a size of 1 to 20% of a size of the metal film.

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