JP2004165308A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device wherein a light emitting element formed with electrodes on one and the same surface can be stably mounted by flip chip bonding technology with respect to lead electrodes located in a concave portion of a package. <P>SOLUTION: The light emitting device comprises the package 7 which has the concvave portion and is formed by insert molding so that the pair of positive and negative lead electrodes 4 may be exposed on the bottom of the concave portion, and the light emitting element 1 mounted face down on the lead electrodes 4. Between the lead electrodes and the light emitting element 1, there is a sub-mount 2 whereon the light emitting element can be mounted. The sub-mount 2 is provided with a conductive member at least on the front surface, and the conductive member is electrically connected to the light emitting element 1 and the lead electrodes 4 via a conductive joint member 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light-emitting diode that emits red light from ultraviolet light that is optimal for a light source of a display, optical communication, OA equipment, or portable equipment, and has a particularly excellent heat-dissipating path and reduces mechanical stress from the outside. The present invention relates to a light-emitting device having excellent durability.
[0002]
[Prior art]
Today, light emitting diodes capable of emitting ultraviolet light, light emitting diodes and laser diodes capable of emitting white light, in addition to light emitting diodes capable of emitting RGB (red, green, blue) light with high luminance have been developed as light emitting devices. These semiconductor light emitting devices have excellent characteristics such as high luminance, low power consumption and long life. For this reason, it has begun to be used not only for various displays outdoors and indoors, for traffic lights such as traffic and railroads, for various indicators and signs, and for backlights of liquid crystal devices, but also as lighting itself.
[0003]
As such a light emitting device, a surface mount type light emitting device shown in FIGS. 14 and 15 is used. 14 and 15 is called a frame insert type, in which a pair of positive and negative lead electrodes to which a light emitting element is electrically connected are injected by a resin so as to be sandwiched from above and below by a resin. Is integrated with the resin package. The end of the lead electrode protrudes to the outside, and is connected to a wiring pattern or the like by bending the end later. The resin package has an opening, and the lead electrode is exposed so that the light emitting element is mounted on the lead electrode. The opening has a tapered shape, and the light from the light emitting element can be efficiently reflected by the inner wall being inclined. Further, the light emitting element has a pair of positive and negative electrodes formed on opposing surfaces. One electrode of the light emitting element is connected to the lead electrode of the resin package, and the other electrode is connected to the other electrode by a conductive wire. Are connected to the lead electrodes of
[0004]
[Patent Document 1]
JP-A-11-87780
[0005]
[Problems to be solved by the invention]
However, when using a light emitting element such as a gallium nitride-based compound semiconductor for which it is difficult to form electrodes on both sides and mounting it on a frame insert type resin package, the electrodes are placed on the same surface as in the face-up mounting mode. It must be formed and electrically connected by two wires. As described above, when two wires are formed, not only is the wire shaded, light extraction efficiency is deteriorated, but also a failure due to a broken wire or the like is caused to lower the yield. Therefore, it is preferable to mount the light emitting element by face down. However, in the case of the frame insert type, when a copper alloy having a thickness of 0.15 mm is used, the distance between the positive and negative lead electrodes is limited to about 0.15 mm, and the light emission between the positive and negative electrodes is 0.1 mm or less. It is difficult to set the element face down with a stable mounting distance. In addition, the lead electrodes do not always have good adhesion to the resin package, and are affected by heat, weight, and ultrasonic waves applied when the light emitting element and the lead electrodes are joined, and both of the lead electrodes facing each other are not affected. Can not be sufficiently alloyed because each of them vibrates slightly. Therefore, an object of the present invention is to provide a surface-mounted light-emitting device which has high stability and extremely high reliability using a flip-chip type light-emitting element.
[0006]
[Means for Solving the Problems]
A semiconductor light emitting device according to claim 1 of the present invention has a concave portion, a package formed by insert molding so that a pair of positive and negative lead electrodes are exposed on the bottom surface of the concave portion, and a package mounted face down on the lead electrode. A light emitting device, comprising: a submount between which the lead electrode and the light emitting element can be mounted, the submount having a conductive member on at least a surface thereof, The member is electrically connected to the light emitting element and the lead electrode by a conductive bonding member. With such a configuration, the light-emitting element and the lead electrode can be electrically connected with good stability by face-down mounting, so that a highly reliable surface-mounted light-emitting device can be obtained.
[0007]
Further, in the semiconductor light emitting device according to claim 2 of the present invention, the submount has a rectangular shape extending in the direction between the lead electrodes. With such a configuration, the submount is arranged from above the positive electrode to above the negative electrode, and the light emitting element can be electrically connected to the lead electrode.
[0008]
Further, in the semiconductor light emitting device according to claim 3 of the present invention, the length of the short side of the submount is longer than the diagonal line of the light emitting element. With such a configuration, the adhesion between the conductive member formed on the submount surface and the light emitting element by the conductive bonding member can be enhanced, and the device can be used with good stability.
[0009]
Further, in the semiconductor light emitting device according to claim 4 of the present invention, the submount has at least twice the area of the light emitting element. With such a configuration, heat dissipation is improved, and handling becomes easy when mounting on a lead electrode.
[0010]
Further, in the semiconductor light emitting device according to claim 5 of the present invention, the submount has a through hole penetrating in the thickness direction, and the through hole is continuous with the conductive members on the upper surface and the lower surface of the submount on the inner wall. An upper surface and a lower surface of the submount are electrically connected to each other through the through hole. With such a configuration, a heat radiation path can be further provided at a position close to the light emitting element, and heat radiation efficiency can be increased.
[0011]
In the semiconductor light emitting device according to claim 6 of the present invention, a plurality of through holes are formed. With such a configuration, the above-described heat radiation efficiency can be further enhanced.
[0012]
Further, in the semiconductor light emitting device according to claim 7 of the present invention, the central axis of the light emitting element coincides with the central axis of the submount, and the through hole is located at a position symmetrical with respect to the central axis at the outer peripheral portion of the light emitting element. Is formed. Such a configuration is preferable because the stability of the mounting portion of the light emitting element is increased, and there is no deviation in the adhesion and the heat radiation path.
[0013]
Further, in the semiconductor light emitting device according to claim 8 of the present invention, the through hole has a cylindrical shape. Such a configuration is preferable because the conductive members formed on the upper surface and the lower surface of the submount on which the light emitting element is mounted can easily conduct, and the heat flow can be smoother.
[0014]
Further, in the semiconductor light emitting device according to claim 9 of the present invention, the bonding portion is in contact with at least a part of the inner wall of the through hole. With such a configuration, the bonding area between the submount and the conductive bonding member can be further increased, so that separation and displacement of the submount from the lead electrode can be suppressed.
[0015]
Further, in the semiconductor light emitting device according to claim 10 of the present invention, the submount is made of glass epoxy resin or BT resin. With such a configuration, the submount can be formed relatively easily.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
1 and 2 show a light emitting device according to an embodiment of the present invention.
A submount is arranged inside the package in which the lead electrodes are integrally formed so as to straddle both the positive and negative electrodes of the lead electrodes. Conductive members are formed on the upper and lower surfaces of the submount. The conductive member on the lower surface of the submount is in a state of being electrically connected to the lead electrode. The conductive members on the upper surface of the submount are formed so as to be separated from each other so that the light emitting elements are placed with their electrode forming surfaces facing each other and can be electrically connected.
[0018]
With such a structure, the light-emitting element can be mounted face down with good stability. The light from the light emitting element is emitted to the outside from the substrate side, so that the efficiency of taking out the light to the outside is improved, and since there is no need for a wire for conducting, there is no defect due to disconnection or the like. , The yield can be increased. Further, since the submount is formed with a conductive member made of a thin metal thin film on a relatively hard insulating substrate or the like, it is affected by micro-vibration that occurs when the electrode of the light emitting element and the conductive member are joined. It can be alloyed without. Therefore, peeling, displacement, and the like of the light-emitting element can be prevented, so that a highly reliable light-emitting device can be provided.
[0019]
Further, when a through hole is formed in the submount as shown in FIG. 3, it is possible to provide a conductive material also inside the through hole, heat radiation can be improved, and furthermore, it is arranged on the lead electrode. In this case, the conductive bonding member used in the process can be provided up to the inside of the through hole, so that the adhesion is improved.
[0020]
Further, after the submount on which the light emitting element is mounted is placed so as to extend between the two lead electrodes, a light transmitting resin such as an epoxy resin or a silicone resin is formed. Can also be sealed. In this case, the light emitting element and the submount can be protected, and the luminance of light can be increased by mixing a glass filler or the like.
[0021]
In addition, it is also possible to integrate the light emitting element and the submount in advance with a sealing resin before disposing them in the package recess as shown in FIG. By doing so, the adhesion between the light emitting element and the submount can be further improved and peeling can be prevented, so that it is easy to handle. By incorporating a fluorescent substance or a diffusing agent into the sealing resin, the light emitting property can be further improved. Can also be increased. Hereinafter, each configuration in the embodiment of the present invention will be described in detail.
[0022]
(Light emitting element)
In the present invention, the light-emitting element is not particularly limited, but has a pair of positive and negative electrodes on the same surface, and when a fluorescent substance is used, a light-emitting layer capable of emitting an emission wavelength capable of exciting the fluorescent substance is used. Is preferred. As such a semiconductor light emitting device, various semiconductors such as AlInGaP and GaN can be cited, but a nitride semiconductor (In) capable of emitting a short wavelength light capable of efficiently exciting a fluorescent substance can be used. _X Al _Y Ga _1-XY N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1) are preferred. Examples of the semiconductor structure include a homostructure having a MIS junction, a PIN junction, and a pn junction, a heterostructure, and a double heterostructure. Various emission wavelengths can be selected depending on the material of the semiconductor layer and the degree of mixed crystal thereof. Further, a single quantum well structure or a multiple quantum well structure in which the semiconductor active layer is formed as a thin film in which a quantum effect occurs can be used.
[0023]
When a nitride semiconductor is used, a material such as sapphire, spinel, SiC, Si, or ZnO is preferably used for the semiconductor substrate. In order to form a nitride semiconductor with good crystallinity with good mass productivity, it is preferable to use a sapphire substrate. A buffer layer of GaN, AlN, GaAlN, or the like is formed on the sapphire substrate, and a nitride semiconductor having a pn junction is formed thereon.
[0024]
As an example of a light emitting device having a pn junction using a nitride semiconductor, a first contact layer formed of n-type gallium nitride, a first cladding layer formed of n-type aluminum-gallium nitride on a buffer layer, A double hetero structure in which an active layer formed of indium gallium nitride, a second cladding layer formed of p-type aluminum gallium nitride, and a second contact layer formed of p-type gallium nitride are sequentially stacked.
[0025]
A nitride semiconductor shows n-type conductivity without doping impurities. When a desired n-type nitride semiconductor is formed, for example, to improve luminous efficiency, it is preferable to appropriately introduce Si, Ge, Se, Te, C, or the like as an n-type dopant. On the other hand, in the case of forming a p-type nitride semiconductor, the p-type dopant such as Zn, Mg, Be, Ca, Sr, or Ba is doped. Since it is difficult to make a nitride semiconductor p-type only by doping it with a p-type dopant, it is preferable to lower the resistance by introducing a p-type dopant and then heating the furnace or irradiating plasma. After the electrodes are formed, a light emitting element made of a nitride semiconductor can be formed by cutting the semiconductor wafer into chips.
[0026]
In the light-emitting diode of the present invention, in order to emit white light, the emission wavelength of the light-emitting element is preferably 400 nm or more and 530 nm or less in consideration of the complementary color relationship with the emission wavelength from the fluorescent substance and the deterioration of the light-transmitting resin. , 420 nm or more and 490 nm or less. In order to improve the excitation and luminous efficiency of the light emitting element and the fluorescent substance, respectively, it is more preferably 450 nm or more and 475 nm or less.
[0027]
(Submount)
As shown in FIG. 2, the submount according to the embodiment of the present invention is configured such that a light emitting element is mounted on a conductive member formed on an upper surface, and a conductive member formed on a lower surface is a lead integrated with a package. Joined with electrodes. Since the conductive member is patterned by etching a thin film of copper or the like formed on the surface of the submount, the conductive member can be provided with a smaller interval than between the positive and negative lead electrodes in the package. With such a configuration, the light emitting element and the lead electrode can be electrically connected with good stability. As the material of the submount, any material can be used as long as it is easily processed and durable. As specific examples, glass epoxy resin described later, or various things such as copper, aluminum, various alloys, and ceramics can be used.
[0028]
When the submount is made of a conductive material such as a metal material, the heat generated in the light emitting element can be efficiently guided to the outside because the submount has a higher thermal conductivity than the insulating material. As a material used for the conductive member, a material having good heat conductivity is preferable in order to efficiently extract heat from the light emitting element to the outside, and Au, Cu, Al, an alloy thereof, or the like can be suitably used. In particular, copper and aluminum can be suitably used because of ease of processing. When a conductive material is used for the submount as described above, SiO 2 is used for electrical insulation. ₂ And SiN _X After forming an insulating film such as, for example, copper, gold, a thin film pattern such as silver, an alloy containing these metals, a laminated film containing these metals, such as a film formed by CVD, sputtering or plating can be suitably used. it can. Further, a metal or an alloy having a high reflectance can be appropriately used according to the emission wavelength.
[0029]
If the submount is made of a semiconductor material, it is possible to provide a protection element inside the submount, and it is possible to increase the electrostatic withstand voltage.
[0030]
Further, it is preferable to use an insulating material because it is easy to handle. For example, a submount can be formed by forming a conductive member on the above-described glass epoxy resin flat plate. Such a conductive member is provided so as to be continuous from the upper surface to the lower surface of the submount in order to conduct an electrode provided on the light emitting element and a lead electrode of the package. The conductive member may be provided so as to be exposed on the side surface of the submount. In the case where a through hole is provided as shown in FIG. 5, the conductive member may be provided inside the through hole. In the case where the light emitting element is provided through the through hole, the light emitting element may be provided only on the side where the light emitting element is arranged as shown in FIG. 6, but by covering the entire inner wall of the through hole, a more effective heat radiation effect can be obtained. When the distance between the positive and negative electrodes of the light emitting element is 0.1 mm, the conductive member on the upper surface of the submount can be provided with an interval of about 0.05 to 0.08 mm so that the electrodes can be joined to these electrodes. Because of this, face-down implementation is also possible.
[0031]
The above-mentioned through-hole can be formed using a flat plate made of a glass epoxy resin having a surface on which a copper thin film for forming a conductive member is formed in advance by a drill, a laser, a punching process, or the like. By providing the through-hole, the heat dissipation is further enhanced, and the inner wall of the through-hole is in contact with and fixed to the conductive bonding member, so that the bonding with the lead electrode can be further strengthened.
[0032]
Such a through hole is formed so as to have openings on the upper surface and the lower surface of the submount on which the light emitting element is mounted. If the submount is electrically connected to the light emitting element, a through hole can be provided near the mounting portion of the light emitting element. However, if the through hole is formed separately from the light emitting element, stability is improved. This is preferable because the light emitting element can be mounted on the submount well.
[0033]
Further, the number and size of the through holes are not limited. Although only one through-hole can be provided, providing a plurality of through-holes increases the portion covered with the conductive material and expands a heat-dissipating path, thereby improving heat-dissipating properties. Further, the contact area between the joining member provided for joining with the lead electrode and the inner wall of the through hole increases, so that the adhesion is improved. If the number of through holes is even, for example, the through holes are provided symmetrically with respect to the center of the submount or the center axis of the light emitting element mounted on the center of the submount, the stability and heat dissipation are improved. Is preferred. In FIG. 5, the through-hole has the same shape from the upper surface to the lower surface and is formed substantially directly below, but may be formed to be inclined from the upper surface to the lower surface. In addition, it is preferable that the through-hole has a cylindrical shape, since stress is hardly partially concentrated, so that a problem does not occur and heat can be uniformly radiated. However, the shape is not limited to such a shape, and an ellipse, a square, a triangle, and the like can be selected. The shape of the opening, the angle of the side surface of the through hole, and the like are not particularly limited. Further, if the conductive bonding member is formed so as to become smaller as approaching the lower surface as shown in FIG. 9, the conductive bonding member becomes caught inside the through-hole when cured, so that it is more stable and hard to peel off.
[0034]
The size and the like of the submount can be appropriately determined according to the light emitting element and the package. The submount may be narrower than the light emitting element as long as it can be installed across the lead electrodes and the light emitting element can be placed and conducted. If the submount is substantially rectangular and the length is shorter than the diagonal line of the light emitting element, it should be easy to handle and be placed on the lead electrode with good stability. Can be. If the area of the submount is twice or more, or 5 to 100% of the area of the bottom surface of the concave portion of the package, the heat dissipation becomes good. As shown in FIG. 10, the submount can be arranged on the entire surface so as to cover the concave portion of the package. The submount covers part or all of the package exposed between the lead electrodes, and the conductive member on the surface of the submount has high reflectivity, so that light can be suppressed and reflected by the package. Therefore, light can be efficiently extracted to the outside. Further, as described above, the reflectivity can be increased by covering the exposed portion of the package between the lead electrodes with the submount by 5 to 100%, preferably 50% or more.
[0035]
The thickness of the submount is not particularly limited as long as it fits in the package and does not affect the directivity of the light emitting device, but when it is 0.2 to 0.3 mm, the heat radiation becomes good, Since the light emitting element is located at an intermediate portion with respect to the depth of the package, the influence of the thermal stress of the resin sealing the package on the light emitting element is preferably reduced.
[0036]
(package)
The package of the present invention has a concave shape, and a pair of positive and negative lead electrodes is exposed on the bottom surface of the concave portion. When such a package is made of a resin, the lead electrode is sandwiched by a forming mold, and the molten resin is injected from a gate into the closed mold, and is relatively easily formed by insert molding to be cured. can do.
[0037]
The lead electrode can be configured using a high thermal conductor such as iron-containing copper. Further, the surface of the lead electrode may be plated with a metal such as silver, aluminum, copper, or gold to improve the reflectance of light from the light emitting element and prevent oxidation of the lead base material. Further, it is preferable to make the surface smooth in order to improve the reflectance of the surface of the lead electrode. In addition, it is preferable that the area of the lead electrode is large. In this manner, heat dissipation can be increased, and a temperature rise of the light emitting element disposed via the submount can be effectively suppressed. . As a result, a relatively large amount of power can be applied to the light emitting element, and the light output can be improved.
[0038]
The lead electrode is formed by punching a long metal plate using a press to form a portion serving as a positive or negative lead electrode of each package molded body. In the portion corresponding to each package molded body of the long metal plate after the press working, the positive lead electrode is negative so that one end surface thereof faces the one end surface of the negative lead electrode on the bottom surface of the molded package concave portion. Are separated from the lead electrodes.
[0039]
The material used for the package in which the lead electrode is insert-molded is a liquid crystal polymer, polyphthalamide, polybutylene terephthalate, or the like, preferably polyphthalamide, and a package made of such a resin emits light. It is hardly deteriorated by heat or light from the element, and withstands stress such as bending of the lead frame.
[0040]
Further, the inside of the package concave portion can be sealed with a mold resin after joining the submount on which the light emitting element is mounted with the lead electrode.
[0041]
(Conductive bonding member)
The conductive bonding member according to the embodiment of the light emitting device of the present invention includes a first bonding member for bonding the light emitting element and the conductive member on the upper surface of the submount, and a conductive member and a package on the lower surface of the submount. And a second joining member for joining the formed lead electrode.
[0042]
The first joining member is formed by a bump made of aluminum, gold, solder, or the like. Such a bump is placed on the electrode of the light emitting element, placed so as to face the wiring pattern on the light emitting element mounting surface of the submount, and applied with an ultrasonic wave of 0.5 to 2 W at a temperature of about 50 to 150 ° C. While applying a load to the light emitting element, the light emitting element and the submount are joined by alloying of a conductive joining member.
[0043]
The second adhesive member is joined by a conductive paste of silver, gold, or copper. After applying an appropriate amount of such a conductive paste to two portions of the submount mounting portion, the submount is mounted, and thermosetting is performed at 150 ° C. for 1 hour to enable bonding.
[0044]
Further, it is also possible to provide a fixing portion made of an insulating adhesive or the like between the submount and the lead electrode, in addition to the portion where the second adhesive member is provided. At this time, if a fixing portion made of an insulating material is provided in the package portion exposed between the lead electrodes, it is possible to prevent a short circuit or the like due to the conductive adhesive placed on both the lead electrodes flowing out.
[0045]
(Sealing member)
In the embodiment of the present invention, after the light emitting element is mounted on the submount, at least a part of the light emitting element can be covered with a sealing member as shown in FIG. Such a sealing member not only protects the light emitting element, but also has a function as an adhesive for fixing the submount and the light emitting element. The light emitting element and the submount can be adhered to each other with only the first bonding member. However, if stronger adhesion is required, the sealing member is provided so as to cover the light emitting element and the periphery thereof. Can be improved. In the present invention, it is preferable to provide a through-hole and to form the through-hole so as to be continuous to the inside, since the contact area with the submount is increased and the contact can be made three-dimensionally.
[0046]
As a material used as the sealing member, a material including a light reflecting member that reflects light from the light-emitting element or a light-transmitting member that can transmit light can be used, which is cured by heat or light. Possible resins can be used. When a sealing member including a light reflecting member is used, the sealing member may not be provided on the upper surface of the light emitting element, and may be provided so as to be continuous from the side surface of the element to the through hole. By providing the sealing member including the light reflecting member on the side surface of the light emitting element, light can be emitted only from the top surface of the light emitting element. Since the resin used as the sealing member may easily deteriorate depending on the wavelength of light emitted from the light-emitting element, the deterioration can be suppressed by using the sealing member including the light reflecting member only on the side surface. . When the resin is deteriorated and yellowed, light is absorbed, so that the luminous efficiency is reduced. However, such a problem can be avoided by suppressing the deterioration.
[0047]
In the case where a sealing member including a light reflecting member is used as shown in FIG. 8, light can be prevented from being emitted to the submount side by providing the sealing member not only on the side surface but also on the bottom surface. . Although the first conductive member is provided between the submount and the light emitting element, if there is a gap, it is preferable to provide a light reflecting member so as to fill the gap. Since the distance between the bottom surface of the light-emitting element and the submount is short, when light is emitted from the bottom of the light-emitting element, reflection is repeated and the resin is likely to be deteriorated. Such deterioration can be prevented. In this case, the sealing member including the light reflecting member is provided so as to be continuous from the side surface of the light emitting element, and further provided so as to be continuous to the through hole, so that it has adhesiveness to the submount and improves light extraction efficiency. Can be done. Further, even when the light emitting element is provided so as to be continuous from the bottom to the through hole, the light extraction efficiency can be improved.
[0048]
As the light reflecting member, it is preferable to use at least one selected from the group consisting of silicon oxide, barium titanate, titanium oxide, and aluminum oxide. Particles composed of these members can be used as a light reflecting member mixed in a sealing member.
[0049]
In the case where a translucent member is used, it can be provided continuously from the upper surface of the light emitting element to the through hole, so that a stronger adhesive force can be obtained. Then, using the sealing member having both the light reflecting member and the light transmitting member as described above, for example, as shown in FIGS. May be formed so as to reach the through hole from the upper surface of the light emitting element. As described above, the through-hole may be filled with a light-transmitting member or a light-reflecting member, and if provided continuously from at least the side surface of the light-emitting element, the effect of improving the adhesive strength is obtained. Is obtained.
[0050]
When a light-transmitting member is used as shown in FIG. 7, a light diffusing material that diffuses light may be mixed. Thereby, light dispersibility is improved and a uniform light emitting device can be obtained. Further, a fluorescent substance which can be excited by light from the light emitting element and emit light having a wavelength longer than that wavelength may be mixed. Thus, mixed light of light from the light emitting element and light from the fluorescent substance can be emitted, so that a light emitting device having various emission wavelengths can be obtained. After disposing the submount on which the light emitting element is mounted in the package concave part, the fluorescent substance can be contained in the resin that seals the concave part.However, this reduces the amount of the fluorescent substance used. In addition, since they can be uniformly mixed, luminance unevenness and the like can be prevented.
[0051]
The sealing member may be continuous from at least the side surface of the light-emitting element to the through hole, and even if it is continuous to the lower surface, as long as it is formed so as to be continuous through a part of the side surface of the through hole. Good. In addition, it is also possible to provide a space for the second joining member and seal it so that the second joining member can be provided even inside the through hole. Such a sealing member can be provided by potting, or can be provided by a method such as printing and coating after protecting the upper surface of the light emitting element with a mask or the like.
[0052]
(Fluorescent substance)
The fluorescent substance that can be used in the present invention may be an inorganic fluorescent substance or an organic fluorescent substance as long as the fluorescent substance can be excited by an emission wavelength emitted from the light-emitting element and emit visible light having a longer wavelength than that light. Emission colors of all visible light from purple to red can be applied. Specifically, examples of the inorganic phosphor include a silicate-based phosphor, a phosphate-based phosphor, an aluminate-based phosphor, a rare-earth-based phosphor, an rare-earth-based phosphor, and a zinc sulfide-based phosphor. . Specifically, in the case of a green light-emitting phosphor, Y ₂ SiO ₅ : Ce, Tb, MgAl ₁₁ O ₁₉ : Ce, Tb, BaMg ₂ Al ₁₆ O ₂₇ : Mn, (Zn, Cd) S: Ag, ZnS: Au, Cu, Al, ZnS: Cu, Al, SrAl ₂ O ₄ : Eu, (SrCaBa) for blue light-emitting phosphor ₅ (PO ₄ ) ₃ Cl: Eu, (BaCa) ₅ (PO ₄ ) ₃ Cl: Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, Sr ₅ (PO ₄ ) ₃ Cl: Eu, Sr ₂ P ₂ O ₇ : Eu, ZnS: Ag, Al, ZnS: Ag, Al (pigmented), ZnS: AgCl, ZnS: AgCl (pigmented), and Y for the red light emitting phosphor ₂ O ₂ S: Eu, Y ₂ O ₂ S: Eu (pigmented), Y ₂ O ₃ : Eu, 3.5MgO.0.5MgF ₂ ・ GeO ₂ : Mn, Y (PV) O ₄ : Eu, 5MgO.3Li ₂ O ・ Sb ₂ O ₅ : Mn, Mg ₂ TiO ₄ : Mn and the like. As a material having relatively high luminous efficiency, SrAl ₂ O ₄ : Eu, Sr for blue light emitting phosphor ₅ (PO ₄ ) ₃ Cl: Eu, Y for the red light emitting phosphor ₂ O ₂ S: Eu.
[0053]
【Example】
(Example 1)
A flat plate made of glass epoxy is used as the submount. A copper thin film as a conductive member is formed on the upper and lower surfaces of the flat plate by bonding or lamination. Next, a negative film is attached to a flat plate, exposed, and removed by chemical etching or the like to form a copper thin film pattern as shown by the hatched portion in FIG. Using a drill, etching, laser, or the like, this copper thin film forming plate is formed so that a plurality of through holes are arranged in the X direction and the Y direction as shown in FIG. Next, as shown in the cross-sectional view of FIG. 13C, the copper thin film is formed so as to be continuous from the upper surface to the lower surface via the through hole, through the through hole. As a result, the through-holes arranged in the X direction are provided so as to be continuous, but a copper thin film is formed such that the glass epoxy resin is exposed apart from each other on the upper surface and the lower surface. That is, the copper thin films of the four through holes arranged in the X direction are continuous, and the copper thin films of the two through holes arranged in the Y direction are formed without contact.
[0054]
Next, as shown in FIG. 13D, the light emitting element is arranged on the copper thin film so as to be in contact with both of the copper thin films formed between the through holes arranged in the Y direction and apart from each other. At this time, a glass epoxy flat plate was placed on a heater heated to 100 ° C., and a gold bump was applied to the mounting portion of the light emitting element of the glass epoxy flat plate while applying a 1 W ultrasonic wave and a load of 60 gf using a bump bonder. Form. Thereafter, the light emitting element is alloyed on the glass epoxy flat plate while applying heat, load and ultrasonic waves by a mounter.
[0055]
Next, as a light reflecting member, TiO ₂ Is potted on the through hole as shown in FIG. At this time, TiO ₂ It is necessary to control the amount of the resin so that the contained resin does not cover the upper surface of the light emitting element. TiO ₂ After the resin is cured, the flat plate is cut along the broken line in FIG. 13 (f) to obtain individual submounts on which the light emitting elements are mounted as shown in FIG. 13 (g). The submount thus formed has a shape with a short side of 0.6 mm, a long side of 1.4 mm, and a thickness of 0.3 mm, and the distance between the copper thin films on the upper surface of the submount is 0.08 mm. is there. The distance between the electrodes of the mounted light emitting element is 0.1 mm.
[0056]
Next, the lead electrodes are placed in a resin package in which insert molding is performed. In the resin package, a portion to be a lead electrode is formed by punching a metal plate made of a copper alloy metal having a thickness of 0.15 mm using a press, and the pair of positive and negative lead electrode portions thus formed is placed in a mold. It is inserted and closed, and a resin is poured into a mold and cured to form. The resin package has a concave shape, and a part of the package is exposed between a pair of positive and negative lead electrodes and a lead of 0.15 mm. The copper thin film on the lower surface of the submount on which the above-described light emitting element is mounted and each lead electrode are joined with a silver paste so as to cross the positive and negative lead electrodes in such a package. The light-emitting device of the present invention can be obtained by sealing.
[0057]
(Example 2)
In the first embodiment, the light emitting element mounted on the glass epoxy resin flat plate on which the conductive member made of the copper thin film is formed by the gold bump is cut, and the individual light emitting element mounted thereon is cut. Split as mount. Next, using a silver paste as a conductive bonding member, the submount was bonded to a lead electrode of a resin package. Since the conductive bonding member hardens after entering the inside of the through hole, the bonding between the submount and the lead electrode can be made strong. Next, the inside of the concave portion of the package is sealed with epoxy resin. The epoxy resin contains 5% by weight of YAG. With such a structure, the light-emitting device of the present invention can be obtained.
[0058]
【The invention's effect】
According to the present invention, by using a submount having a sufficient length for mounting between the lead electrodes, the light emitting element can be electrically connected with good stability by face-down mounting, so that the reliability is improved. And a surface-mounted light-emitting device with a rich surface.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a light emitting device of the present invention.
FIG. 2 is a schematic plan view showing a light emitting device of the present invention.
FIG. 3 is a schematic plan view showing another light emitting device of the present invention.
FIG. 4 is a schematic sectional view showing AA in FIG. 3;
FIG. 5 is a schematic sectional view showing another light emitting device of the present invention.
FIG. 6 is a schematic sectional view showing another light emitting device of the present invention.
FIG. 7 is a schematic sectional view showing another light emitting device of the present invention.
FIG. 8 is a schematic sectional view showing another light emitting device of the present invention.
FIG. 9 is a schematic sectional view showing another light emitting device of the present invention.
FIG. 10 is a schematic plan view showing another light emitting device of the present invention.
FIG. 11 is a schematic sectional view showing another light emitting device of the present invention.
FIG. 12 is a schematic sectional view showing another light emitting device of the present invention.
FIG. 13 is a process chart showing a step of forming a light emitting device of the present invention.
(A) Schematic diagram of a flat plate on which a conductive member is formed
(B) Schematic diagram of a flat plate with a through hole formed
(C) Sectional view of FIG.
(D) Schematic view of a flat plate on which light emitting elements are arranged
(E) Sectional view of FIG.
(F) Schematic view of substrate on which light reflecting member is formed
(G) Sectional view of FIG.
FIG. 14 is a schematic plan view showing a light emitting device shown for comparison with the present invention.
FIG. 15 is a schematic sectional view showing AA in FIG. 14;
[Explanation of symbols]
1. Light emitting element
2. Submount
3. Conductive member
4. Lead electrode
5. First joining member
6. Second joining member
7. package
8. Wire
9. Through hole
10. Translucent member
11. Sealing member including light reflecting member

Claims (10)

A light emitting device having a concave portion, a package formed by insert molding such that a pair of positive and negative lead electrodes are exposed on the bottom surface of the concave portion, and a light emitting element mounted face down on the lead electrode,
Between the lead electrode and the light emitting element, has a submount capable of mounting the light emitting element, the submount has a conductive member at least on the surface, the conductive member, the light emitting element and the A light emitting device, which is electrically connected to a lead electrode by a conductive bonding member. 2. The semiconductor light emitting device according to claim 1, wherein the submount has a rectangular shape extending in a direction between the lead electrodes. The semiconductor light emitting device according to claim 2, wherein a length of a short side of the submount is longer than a diagonal line of the light emitting element. The semiconductor light emitting device according to claim 1, wherein the submount has an area at least twice as large as the light emitting element. The submount has a through hole penetrating in the thickness direction, the through hole has a conductive member on the inner wall that is continuous with a conductive member on the upper surface and the lower surface of the submount, and the submount is formed through the through hole. 5. The semiconductor light emitting device according to claim 1, wherein an upper surface and a lower surface of the submount are electrically connected. The semiconductor light emitting device according to claim 5, wherein a plurality of the through holes are formed. 7. The light emitting device according to claim 6, wherein a central axis of the light emitting element coincides with a central axis of the submount, and the through hole is formed at a position symmetrical with respect to the central axis at an outer peripheral portion of the light emitting element. Semiconductor light emitting device. 8. The semiconductor light emitting device according to claim 5, wherein said through hole has a cylindrical shape. 9. The semiconductor light emitting device according to claim 5, wherein the adhesive portion contacts at least a part of an inner wall of the through hole. 10. 10. The semiconductor light emitting device according to claim 1, wherein the submount is made of glass epoxy or BT resin.

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