JP2010087181A - Package for optical elements, semiconductor light emitting apparatus, and illuminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat radiation and assemblability in a semiconductor light emitting apparatus. <P>SOLUTION: A package 1 for optical elements is constructed such that a heat slag 20 is arranged in its internal space 11 for a ring-shaped base 10, a gap between the inner peripheral surface 11a of the base 10 and the outer circumference of the heat slag 20 is filled with an insulating material 40, and leads 31 and 32 are inserted so as to pass through the insulating material 40. The insulating material 40 fixes the heat slag 20 and the leads 31 and 32 such that they are mutually insulated. Stretching parts 31c and 32c stretching outward of the leads 31 and 32 are bent in a direction of the base 10's outer edge and extended beyond the outer edge of the base 10 along the base plane of the base 10, and its terminal parts 31d and 32d are bent to the upper side in a perpendicular direction. The heat slag 20 is provided with a mount section 21 and a drooping part 22, and its bottom surface 22b is exposed from the insulating material 40. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an optical element package including a mount portion on which an optical element such as an LED is mounted, and leads for electrically connecting the optical element to the outside.

  2. Description of the Related Art As a package for an optical element for packaging an optical element such as a light emitting diode (LED), a package having a base on which the optical element is mounted and a lead for electrically connecting the optical element to an external circuit is known. . Then, an optical element is mounted on the optical element package, the optical element and the conductive member are wire-bonded, and sealed with a transparent resin to form a semiconductor light emitting device.

FIG. 10 is a diagram showing a semiconductor light emitting device 118 disclosed in Patent Document 1. In FIG.
In this semiconductor light emitting device 118, the ceramic base 102 is made of Al ₂ O ₃ , AlN, or the like, and a through hole 107 through which the lead terminal 106 is inserted is formed.
The lead portion 104 of the lead terminal 106 passes through the through hole 107 and is filled with a sealing glass 108 made of borosilicate glass, and is sealed so as to maintain insulation and airtightness. The element connection terminals 103 are arranged so as to face the upper surface side of the ceramic substrate 102, and the mounting terminals 105 are arranged so as to face the bottom surface side of the ceramic substrate 102.

On the ceramic base 102, an element mounting member 109 made of copper or a copper alloy is brazed with a brazing material 110 made of an Ag alloy or the like.
In the element mounting member 109, an element mounting recess 111 is formed in a cup shape, and a silver or silver alloy film 114 is formed on the surface of the recess. The optical semiconductor element 113 mounted in the element mounting recess 111 is connected to the element connection terminal 103 by the conductive wire 115.

On the ceramic base 102, a lid 117 having a light transmitting portion 116 is provided so as to cover the optical semiconductor element 113.
Such a semiconductor light emitting device is mounted on a mounting board or the like having an external circuit and used for a lighting device or the like.
JP 2006-4987 A

In such a semiconductor light emitting device, there is a need to improve heat dissipation to dissipate heat generated by the optical element to the outside, and it is desired to simplify the assembly process.
For example, when the semiconductor light emitting device 118 is mounted on a mounting substrate, heat is radiated from the optical semiconductor element 113 to the mounting substrate via the element mounting member 109 and the ceramic substrate 102. Since the thermal conductivity is inferior to that of metal and voids are easily generated at the interface with the brazing material 110, heat is not easily released from the optical semiconductor element 113 to the mounting substrate.

Further, when assembling the semiconductor light emitting device, a step of brazing the element mounting member 109 to the ceramic base 102 is necessary, and the positions of the elements may be shifted in the brazing step.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a semiconductor light emitting device that improves heat dissipation, can be assembled with high accuracy, and has a simple assembly process.

  To achieve the above object, according to the present invention, there is provided an optical element package for packaging an optical element, wherein a ring-shaped base made of a ceramic material, an inner space surrounded by the ring-shaped base, A heat slag disposed with a gap between them, an insulating material filled in the gap, and a lead that penetrates the insulating material and is inserted from the outside of the package to the inside, and the outside of the insulating material of the lead The heat slug is mounted on the inside of the package as the top surface and the outside side as the bottom surface, and the top surface is exposed inside the package to mount the optical device. The bottom surface was suspended until it was level with the bottom surface of the base, and was exposed outside the package.

In the optical element package of the present invention, it is preferable to further perform the following.
This heat slag is formed of oxygen-free copper or a copper alloy.
In the heat slug, the mount portion has a shape that expands with respect to the suspended portion.
The portion of the heat slug that is suspended is formed so that the cross-sectional shape varies depending on the position in the direction of the suspension.

The bottom surface of the heat slug and the surface of the portion extending along the base bottom surface of the lead are present on the same plane.
A fitting portion for fitting with each other is formed on the outer periphery of the heat slug and the inner peripheral surface of the base.
The position of the penetrating portion penetrating through the gap in the lead is offset toward the base inner peripheral surface side with respect to the outer periphery of the heat slag, and the lead end portion close to the mount portion is bent toward the heat slag side.

The outer peripheral part of the base is formed higher than the mount part.
The base is formed of white highly reflective alumina having a reflectance of 85% or more for light having a wavelength of 450 nm.
An insulating material is comprised with white highly reflective glass.
The extended portion of the lead is extended to the outside of the outer edge of the base, and the terminal portion is bent upward.

The bottom part of the base is sandwiched between the lead insertion part and the terminal part.
As the insulating material, soda glass or borosilicate glass is used.
The lead is composed of an iron-nickel alloy system.
In the optical element package of the present invention, a plurality of heat slugs may be provided.
A semiconductor light emitting device can be configured by mounting an optical element on the electronic component package of the present invention and wire bonding the optical element and the lead.

  The lighting device can be configured by mounting the semiconductor light emitting device on a substrate provided with wiring connected to a driving circuit.

According to the optical element package of the present invention, the heat slag is fixed in the internal space of the base by the insulating material filled between the base inner periphery and the heat slug outer periphery, and the leads are also fixed by the insulating material.
In addition, the heat slag, which is a heat dissipation means, is the mount part on which the top surface is exposed inside the package to mount the optical element, the bottom surface of the heat slag is suspended until it is level with the base bottom surface, and is exposed outside the package, In addition, since the insulating material outer side of the lead is bent in the outer edge direction of the base and extends along the bottom surface of the base, if the optical semiconductor device is configured using the optical element package and mounted on the substrate, If the lead portion extending along the bottom surface of the base is connected to the mounting substrate, the bottom surface of the heat slug approaches or contacts the mounting substrate.

Therefore, the heat generated from the optical element mounted on the mount part is well transmitted downward through the heat slug having good thermal conductivity, and is efficiently radiated from the bottom surface of the heat slug to the mounting substrate.
In addition, even after the lead is soldered to the mounting board, the lead can be freely deformed to some extent, so even if an external force is applied to the lead due to a difference in thermal expansion between the base and the mounting board, the lead is applied to the solder joint. The stress is small. Accordingly, even in a heat cycle test after mounting on the substrate, cracks are unlikely to occur at the solder joint between the lead and the wiring on the mounting substrate.

In particular, when the mounting substrate is made of a metal such as copper or aluminum, if the base is made of a metal material, the difference in thermal expansion itself is reduced, so that the effect of suppressing the occurrence of solder cracks is great.
Moreover, since the lead penetrates the insulating material and is inserted from the outside to the inside of the package, the insulation between the lead and the heat slug is ensured.

  The package for optical elements of the present invention can be assembled by processing the base, the heat slug, and the lead, setting the heat slug and the lead in the through hole of the base, and filling the through hole with the insulating material. it can. Therefore, there is no need to braze the heat slag to the base, and the heat slag can be produced with high precision using press working, so that the assembly accuracy is good and the assembly process is simple.

In the optical element package of the present invention, if the heat slug is formed of oxygen-free copper or a copper alloy, particularly excellent thermal conductivity can be obtained.
In the heat slug, if the mount portion has a shape that expands with respect to the suspended portion, the area of the mount portion can be secured even if the suspended portion is formed thin.

If the hanging part of the heat slug is formed so that the cross-sectional shape differs depending on the position in the drooping direction, the hanging part buried in the insulating material has an anchor effect, so the heat slug is firmly fixed by the insulating material. .
If the bottom surface of the heat slug and the surface of the portion extending along the base bottom surface of the lead are present on the same surface, the bottom surface of the heat slug contacts the mounting substrate when mounted on the mounting substrate. The heat dissipation to the substrate becomes better.

If a fitting portion that fits into each other is formed on the outer periphery of the heat slug and the inner peripheral surface of the base, it is easy to position and arrange the heat slug in the inner space of the base at the time of package assembly.
If the position of the penetrating part that penetrates the gap in the lead is offset to the inner peripheral surface side of the base from the outer periphery of the heat slag, the lead end even if the lead end close to the mount is bent to the heat slag side An area that maintains the insulation between the slag and the heat slug can be secured. Then, by bending the lead end portion toward the center side of the base in this way, the pad area becomes wide and it becomes easy to wire bond to the lead end portion. In addition, since the distance between the bottom surface of the heat slug and the lead can be increased, an effect of preventing a short circuit can be achieved when mounting on the mounting board.

If the outer peripheral portion of the base is formed higher than the mount portion, the upper surface of the mount portion is recessed with respect to the upper surface of the outer peripheral portion of the base, so that the inner surface of the concave portion can function as a reflector.
If the base is made of white highly reflective alumina having a reflectance of 85% or more for light having a wavelength of 450 nm, the reflectance for blue light (short wavelength visible light) on the surface of the base is improved. In particular, when the concave reflector is formed as described above, it contributes to the improvement of the reflectance.

By extending the lead extension part to the outside of the outer edge of the base and bending the end part upward, a fillet is formed in the solder joint and the solder joint strength is increased, so the occurrence of solder cracks is further suppressed. It is done.
In addition, if the bottom part of the base is sandwiched between the lead insertion part and the terminal part, the lead can be temporarily fixed to the bottom part of the base during package assembly. Contributes to improvement.

  Generally, a glass material has a higher viscosity than a resin and is effective for bonding with a wide clearance. Therefore, if soda glass or borosilicate glass is used as an insulating material, a heat slag and a lead can be stably fixed.

1. Configuration of Optical Element Package FIG. 1 shows an optical element package 1 according to an embodiment, where (a) is a top view and (b) is a bottom view. FIG. 2 is a cross-sectional view taken along the line AA ′ in FIG. 1 and 2 show the optical element package 1 in which the optical element 50 is mounted. Here, an LED chip is used as the optical element 50.

The configuration of the optical element package 1 will be described with reference to FIGS. For the sake of explanation, the direction along the plane of FIG. 1 is referred to as the horizontal direction, and the direction perpendicular thereto is referred to as the vertical direction.
The optical element package 1 is used to package an optical element, and forms a gap between a ring-shaped base 10 in which an internal space 11 is formed and an inner peripheral surface 11a of the base 10. As described above, the heat slug 20 inserted into the internal space 11, the leads 31 and 32 inserted so as to penetrate the gap between the inner peripheral surface 11 a and the heat slug 20, and the gap is filled with the heat slug 20 and And an insulating material 40 for fixing the leads 31 and 32 in an insulated state.

The heat slug 20 has a mount portion 21 on which the optical element 50 is mounted on the upper surface side, and a hanging portion 22 extends downward from the mount portion 21. The hanging portion 22 penetrates the interior space 11 in the vertical direction and hangs to the same level as the bottom surface of the base 10 or below.
The periphery of the drooping portion 22 and the leads 31, 32 penetrating portions 31b, 32b is filled with an insulating material 40, but the bottom surface 22b of the drooping portion 22 is exposed as shown in FIG.

(Configuration of base 10 and heat slug 20)
The base 10 is formed of a ceramic material, and as shown in FIGS. 1 (a) and 1 (b), the outer periphery has a substantially square shape when viewed in plan from the vertical direction, and is circular so as to penetrate the center portion thereof. An internal space 11 having a shape is opened to form a ring shape.
If white highly reflective alumina is used as the ceramic material forming the base 10, the reflectance of the surface of the base 10 with respect to blue light (short wavelength visible light) becomes good. In particular, it is preferable to use white highly reflective alumina having a reflectance of 85% or more for light having a wavelength of 450 nm.

The outer peripheral portion 12 of the base 10 is formed higher than the mount portion 21, and an inclined surface 13 that is inclined from the outer peripheral portion 12 to the upper edge of the internal space 11 is formed on the upper surface of the base 10. That is, a mortar-shaped inclined surface 13 is formed around the internal space 11.
It is preferable that the heat slag 20 be integrally formed of a material made of a metal or an alloy because the heat conductivity becomes good and the heat slag 20 can be accurately formed. In particular, if oxygen-free copper or a copper alloy is used as a material, good thermal conductivity can be obtained.

The mount portion 21 is formed in a plate shape extending in the horizontal direction, and is substantially rectangular when viewed in plan from the vertical direction. The length in the vertical direction of FIG. 1 is set to be approximately equal to the diameter of the internal space 11. The inner space 11 is arranged so as to run vertically.
The horizontal length of the mount portion 21 is set to be shorter than the vertical length, and a gap is formed between the side wall 21 a of the mount portion 21 and the inner peripheral surface 11 a of the internal space 11 on both sides of the mount portion 21. The upper end portion 31a of the lead 31 and the upper end portion 32a of the lead 32 are arranged in each gap. The insulating material 40 is also filled around the mount portion 21 and the upper end portions 31a and 32a.

The outer periphery of the mount part 21 and the inner peripheral surface 11a of the base 10 are formed with fitting parts that fit each other. That is, a fitting convex portion 21b protruding in the vertical direction of FIG. 1 is formed on the short side portion of the mount portion 21 near the inner peripheral surface 11a, while the fitting convex portion 21b is filled in the internal space 11 of the base 10. A fitting recess 11b to be stuck is formed.
As a result, when the heat slug 20 is set in the internal space 11 when the package is assembled, the mounting portion 21 is set at a fixed position in the center of the internal space 11 when the fitting convex portion 21b is fitted into the fitting concave portion 11b. become.

In addition, although such a fitting convex part 21b may be formed in the hanging part 22, it is preferable to form in the part close | similar to the internal peripheral surface 11a of the mount part 21. FIG.
The upper surface of the mount portion 21 is covered with a plating layer (not shown). The plated layer is formed by laminating a layer of a material selected from gold, silver, a gold alloy, and a silver alloy on the nickel layer, and emits light emitted from the optical element 50 mounted on the mount unit 21. It is designed to reflect.

As shown in FIG. 2, the drooping portion 22 extends downward from the central portion of the mount portion 21.
The shape of the horizontal section of the drooping portion 22 is not particularly limited, and is circular in the example shown in FIG. 1B, but may be a polygon or the like.
Further, the horizontal cross-sectional shape of the drooping portion 22 may be uniform, but as shown in FIG. 2, the cross-sectional shape varies depending on the position in the vertical direction, which fixes the heat slug 20 with the insulating material 40. It is preferable for securing.

That is, since the heat slag 20 has a larger coefficient of thermal expansion than the insulating material 40, the interface between the heat slag 20 and the insulating material 40 may be peeled off due to the temperature change. This is because, if the position differs depending on the position in the vertical direction, an anchor effect is produced when the drooping portion 22 is buried in the insulating material 40.
Basically, by providing a portion whose cross-sectional area is enlarged on the lower side with respect to the drooping portion 22, it is possible to prevent the heat slug 20 from being pulled upward from the insulating material 40. For example, as shown in FIG. 2, the drooping portion 22 may be formed so that the cross-sectional area is large at the central portion in the vertical direction and the cross-sectional area is small toward the upper and lower ends. You may form a cross-sectional area smaller than a part.

Even if the cross-sectional area of the drooping portion 22 is uniform, the anchor effect can be obtained if the outer peripheral surface of the drooping portion 22 has a portion that changes instead of being straight. For example, the anchor effect can be obtained also when a screw is formed on the outer periphery of the drooping portion 22.
The bottom surface 22b of the drooping portion 22 and the lower surfaces of the leads 31c and 32c are preferably set so as to be on the same plane.

In addition, when glass is used as the insulating material 40, the glass generally has a higher viscosity at the time of melting than the resin material, and air bubbles are likely to remain. Therefore, the shape related to the peripheral surface 22a of the heat slag 20 described above takes air bubbles out of consideration. However, it should be inclined or stepped so as not to cause bubble accumulation.
In addition, when glass is used for the insulating material 40 and a copper-based material is used for the heat slag 20, the adhesiveness between the two is relatively good, and the difference in thermal expansion coefficient is large, so stress is generated by heating and cooling, There is a risk of cracks in the insulating material 40 made of glass. In order to prevent this, nickel plating is applied to the surface of the heat slag 20 made of a copper-based material to prevent the insulating material 40 made of glass and the heat slag 20 made of a copper-based material from sticking to each other.

As shown in FIG. 2, the concave surface 14 is formed by the inclined surface 13, the upper surface of the mount portion 21, the upper end portions 31 a and 32 a of the leads, and the upper surface of the insulating material 40, and the mount portion 21 is formed at the bottom of the concave surface 14. positioned. The concave surface 14 functions as a reflector that efficiently reflects light emitted from the optical element 50 upward.
(Configuration of leads 31 and 32)
The leads 31 and 32 are formed by bending a long metal plate material. As the metal plate, for example, a plate material made of an iron-nickel alloy is used.

The leads 31 and 32 have through portions 31b and 32b inserted so as to pass through the gap between the peripheral surface 22a of the hanging portion 22 and the inner peripheral surface 11a of the base 10, and the through portions 31b and 32b are It is embedded and fixed in the insulating material 40.
The penetrating portions 31b and 32b of the lead pass horizontally between the peripheral surface 22a of the drooping portion 22 and the inner peripheral surface 11a of the internal space 11, and are positioned outside (the outer periphery of the heat slug 20 and the inner peripheral surface of the base 10). 11a, but not on the center between 11a and the inner peripheral surface 11a.

  Further, in the leads 31 and 32, end portions 31a and 32a on the side adjacent to the mount portion 21 are bent toward the mount portion 21 side. That is, the penetrating portions 31b and 32b extend in the vertical direction, and the lead end portions 31a and 32a extend in the horizontal direction to form a pad area. Thus, the wire bonding process is facilitated by securing the horizontal length of the lead end portions 31a and 32a and providing the pad area.

  As described above, since the positions of the through portions 31b and 32b are offset to the outside, even if the horizontal lengths of the lead end portions 31a and 32a are set to be large, the tips of the lead end portions 31a and 32a are The insulation between the leads 31 and 32 and the heat slag 20 can be ensured without contacting the heat slag 20. In addition, when mounted on the mounting substrate 3, there is an effect of preventing a short circuit between the leads 31 and 32 and the heat slug 20.

On the other hand, the extending portions 31 c and 32 c extending downward from the insulating material 40 are bent toward the outer edge of the base 10 with respect to the through portions 31 b and 32 b and extend along the bottom surface of the base 10.
The extending portions 31c and 32c extend outward beyond the outer extension of the base 10, and the end portions 31d and 32d are bent upward. Accordingly, the through portions 31b and 32b and the end portions 31d and 32d are disposed to face each other in the horizontal direction with the base 10 interposed therebetween.

As shown in FIG. 5, a protrusion 31f is provided at the penetrating portion 31b, and a protrusion 31g is provided at the terminal end 31d. As shown in FIG. 2, the base 10 is sandwiched between the protrusion 31f and the protrusion 31g. Yes.
Similarly, a protrusion 32f is provided at the penetrating portion 32b, and a protrusion 32g is provided at the terminal end 32d, and the base 10 is sandwiched between the protrusion 32f and the protrusion 32g.
In the lead, the width of the end portions 31d and 32d (W2 in FIG. 5) is set narrower than the width of the extended portions 31c and 32c (W1 in FIG. 5) along the bottom surface of the base. Thereby, when the leads 31 and 32 are formed by bending the metal plate material, the end portions 31d and 32d can be easily bent. As shown in FIG. 5, openings 31 e and 32 e are formed in the regions of the leads 31 and 32 that are buried in the insulating material 40.

(Configuration of insulation material)
The insulating material 40 is filled in the internal space 11, covers the peripheral surface 22a of the hanging portion 22 of the heat slug 20, covers the through portions 31b, 32b of the leads 31, 32, and fills the openings 31e, 32e. Has been. Furthermore, the insulating material 40 is also in contact with the lower surfaces of the end portions 31 a and 32 a of the leads 31 and 32.

With such an insulating material 40, the heat slug 20 and the leads 31 and 32 are firmly fixed in an insulated state, and the internal space 11 is sealed.
As the insulating material 40, a material that can fix the heat slug 20 and the leads 31 and 32 in the internal space 11 of the base 10 is used. Specifically, a resin can be used, but soda glass or borosilicate glass is preferable.

In general, glass materials are highly viscous even when melted compared to resins, and are therefore effective for bonding with a wide clearance. Therefore, if a glass material is used as the insulating material 40, the heat slag 20 and the leads 31, 32 can be stably held by keeping the glass material in the internal space 11 even when melted.
In addition, it is preferable to use white highly reflective glass as the insulating material 40 in order to increase the reflectance of the upper surface of the insulating material 40.

(Structure of semiconductor light emitting device 2 and lighting device)
FIG. 2 shows a semiconductor light emitting device 2 in which an optical element is mounted on the optical element package 1, and FIG. 3 shows a state in which this is mounted on a mounting substrate 3.
Here, a light emitting diode (LED) is used as the optical element, but a laser diode or the like may be used.

As shown in FIGS. 2 and 3, in the semiconductor light emitting device 2, the optical element 50 is mounted on the mount portion 21 of the optical element package 1, and the terminals of the optical element 50 and the lead end portions 31 a and 32 a are connected to the wires 51, 52 and connected. In the semiconductor light emitting device 2, the optical element 50 is sealed by filling the inside of the concave surface 14 with a transparent resin.
As shown in FIG. 3B, the semiconductor light emitting device 2 is mounted on the mounting substrate 3 and soldered to the extended portions 31 c and 32 c of the leads 31 and 32 to be used as a lighting device. Note that a wiring pattern (not shown) is formed of a metal such as copper on the surface of the mounting substrate 3, and an insulating film 60 is provided to avoid unnecessary electrical contact with the semiconductor light emitting device 2. Yes.

2. FIG. 4 is a process flow diagram showing a method for manufacturing the optical element package 1 and the semiconductor light emitting device 2.
This will be described with reference to this figure.

In P1 to P4, the base 10, the heat slug 20, the leads 31, 32, and the glass column used in the glass sealing step are produced.
The base 10 is produced by press-molding a material made of alumina powder with a press machine (P1).
The heat slug 20 is produced by press-molding a material made of oxygen-free copper or copper alloy with a press machine (P2).
Leads 31 and 32 are produced by bending a plate material made of an iron-nickel alloy (P3). As needed, it heats at 650 degreeC in the air, and oxidizes.

FIG. 5 shows the metal plate before the lead 31 is bent. The lead 31 is produced by bending the metal plate material along broken lines Y1, Y2, and Y3 in the figure.
A glass column is produced by press-molding glass powder into a columnar shape and pre-baking (P4).
Glass sealing step (P5):
FIG. 6 is a diagram showing a glass sealing step. This will be described with reference to FIG.

The base 10 and the heat slug 20 are mounted at fixed positions of the carbon jig 71 (FIG. 6A). At this time, since the heat slug 20 is set at a fixed position in the internal space 11 by fitting the fitting convex portion 21b of the mount portion 21 to the fitting concave portion 11b of the internal space 11, the positioning of the heat slug 20 is easy. is there.
The leads 31 and 32 are set so as to penetrate the internal space 11 of the base 10 on both sides of the heat slug 20, and fixed with the carbon jig 72 (FIG. 6B). When the lead 31 is set, if the base 10 is sandwiched between the protrusion 31f and the protrusion 31g and temporarily fixed, the lead 31 can be easily set at a fixed position.

The glass column 73 is inserted between the heat slug 20 and the leads 31 and 32 (FIG. 6C), and heated to a temperature equal to or higher than the temperature at which the glass melts (for example, 1000 ° C.) to be cooled. During heating and cooling, the positions of the leads 31 and 32 and the base 10 are fixed by the carbon jigs 71 and 72 (FIG. 6D).
The heated glass is melted and partly passes through the openings 31e and 32e of the leads 31 and 32 to fill the entire space in the internal space 11, and the peripheral surface 22a of the drooping portion 22 of the heat slug 20 and the leads The surfaces of the through portions 31b and 32b of the 31 and 32 are covered.

When the glass is cooled, it solidifies to become the insulating material 40, and the heat slag 20 and the leads 31 and 32 are firmly fixed to the base 10 by the insulating material 40.
The one assembled as described above is plated (P6 in FIG. 4).
In this step, it is preferable to form a base layer by nickel plating, and then perform plating with a material selected from gold, silver, and gold-silver alloy.

By the plating process, a nickel underlayer and a plated layer of gold, silver, or a gold-silver alloy are formed on exposed portions of the heat slug 20 and the leads 31 and 32. Thus, when plating with silver or an alloy containing silver, the reflectance with respect to blue light is improved.
Thus, the optical element package 1 is manufactured.
(Production and mounting of semiconductor light-emitting devices)
Using the optical element package 1, the semiconductor light emitting device 2 is manufactured through a die bonding process (P7 in FIG. 4), a wire bonding process (P8 in FIG. 4), and an encap process (P9 in FIG. 4).

These steps will be described with reference to FIG. 7A shows the case without the lens with reflector shown in FIG. 2, and FIG. 7B shows the case with the lens without reflector as a modification.
In the die bonding step P7, an Au—Sn alloy or Ag paste is applied on the mount portion 21 in the optical element package 1, and the optical element 50 is mounted and bonded by heating. The heating temperature is 320 ° C. for Au—Sn alloy and 150 ° C. for Ag.

In the wire bonding step P8, the terminals of the mounted optical element 50 and the lead end portions 31a and 32a are connected by wires (Au wires) 51 and 52. Here, since the lead end portions 31a and 32a extend in the horizontal direction as described above, the connection between the lead end portions 31a and 32a and the wires 51 and 52 can be easily performed.
In the encap process P9, the optical element 50 is sealed by pouring a transparent resin for sealing (epoxy resin or silicon resin) into the concave surface 14 and curing it.

  In the modification shown in FIG. 7 (b), the outer peripheral portion of the base 10 is not formed higher than the mount portion 21, and therefore a concave reflector is not formed. Instead, a lens capping step for mounting the lens 80 so as to cover the optical element 50 is added after the wire bonding step. In the encap process, the optical element 50 is sealed by pouring a transparent resin for sealing between the lens 80 and the optical element package 1 and curing it.

As another modification, until the wire bonding step, the outer peripheral portion of the base 10 is raised as shown in FIG. 7A to form a concave reflector, and in the lens capping step and the encap step, FIG. The lens 80 may be mounted as shown in (b).

The semiconductor light emitting device 2 manufactured as described above is mounted on the mounting substrate 3.

The mounting process will be described with reference to FIG.
As described above, a wiring pattern (not shown) is formed on the surface portion of the mounting substrate 3, and the insulating film 60 is provided. In addition, cream solder 61 is applied on the wiring pattern at positions where the leads 31 and 32 are placed on the mounting substrate 3.
By placing the semiconductor light emitting device 2 on the mounting substrate 3 and heating it in a reflow furnace, the cream solder 61 is melted, and the extended portions 31 c and 32 c of the leads 31 and 32 are soldered onto the mounting substrate 3. The At this time, the melted solder flows so as to wet the surfaces of the terminal end portions 31d and 32d, and a rounded fillet is formed in the solder joint portion 62, whereby the strength of the solder joint portion 62 is increased. Moreover, the state of soldering can also be confirmed by observing this fillet shape.

3. As described above, the optical element package 1 according to the present embodiment is fixed in a state where the leads 31 and 32 are insulated from the heat slug 20 by the insulating material 40. As explained in the above manufacturing method, the base 10, the heat slug 20 and the leads 31 and 32 are prepared in advance, and the heat slug 20 and the leads 31 and 32 are set in the internal space 11 of the base 10. It can be produced by a method of filling a material.

Therefore, the base 10, the heat slug 20, and the leads 31 and 32 can be accurately manufactured by press working. Moreover, since the optical element package 1 can be produced by a method of fixing them with the insulating material 40, a process of brazing the heat slag to the base is unnecessary, and the manufacturing process is simple.
Further, the bottom surface 22 b of the heat slug 20 is exposed without being covered with the insulating material 40, and the extended portions 31 c and 32 c of the leads 31 and 32 are bent toward the outer edge of the base 10 to form the bottom surface of the base 10. As shown in FIG. 3, if the extended portions 31 c and 32 c are soldered to the mounting substrate 3 during mounting, 22 b immediately below the mounting portion 21 approaches or contacts the mounting substrate 3. Therefore, the heat generated from the optical element 50 is transmitted downward through the heat slug 20 having good thermal conductivity, and is efficiently radiated from the bottom surface 22b of the hanging portion 22 to the mounting substrate 3. In particular, if the heat slag 20 is formed of a copper material (oxygen-free copper or copper alloy), the heat conductivity is good, so that excellent heat dissipation is obtained.

Here, when the bottom surface 22b of the heat slug 20 and the surfaces of the extended portions 31c and 32c of the leads 31 and 32 are positioned on the same surface, the bottom surface is obtained when the semiconductor light emitting device 2 is mounted on the mounting substrate 3. Since 22b contacts the mounting board | substrate 3, the heat dissipation to the mounting board | substrate 3 becomes more favorable.
Further, the leads 31 and 32 are not directly joined to the base 10, but are fixed through the insulating material 40, and the extended portions 31c and 32c of the leads are bent toward the outer edge of the base 10 to form the base 10. The leads 31 and 32 can be freely deformed to some extent even after being mounted. Therefore, even if an external force is applied to the leads 31 and 32 due to the difference in thermal expansion between the base 10 and the mounting substrate 3, the leads 31 and 32 are deformed and absorb this force. The stress applied to is small. Therefore, even in the heat cycle test, cracks are unlikely to occur in the solder joint portion 62.

In the optical element package 1, when the base 10 is formed of white highly reflective alumina as described above, the reflectance of the base surface with respect to blue light becomes good. This point will be described with reference to FIG.
FIG. 9 is a characteristic diagram showing the reflectance when light of each wavelength is irradiated onto the highly reflective alumina and Ag plating layer in the range of 350 nm to 750 nm.

At a wavelength of 500 nm or longer, all have a reflectivity of about 90%. On the other hand, at a wavelength of 450 nm or less, the reflectance is reduced in the Ag plating layer, whereas the reflectance of about 90% is maintained in the highly reflective alumina. Thus, the surface of white highly reflective alumina has a good reflectivity for short wavelength light of 500 nm or less.
In particular, as shown in FIG. 2, when the outer peripheral portion 15 of the base 10 is made higher than the mount portion 21 and the concave surface 14 serving as a reflector is formed, the reflectance improvement of the inclined surface 13 is greatly improved in the reflectance improvement of the reflector. Contribute.

Further, the surface of the white highly reflective alumina is less subject to a decrease in reflectance over time than the Ag plating layer.
Since glass materials are highly viscous, they are generally effective for bonding with a wide clearance. Therefore, if soda glass or borosilicate glass is used as the insulating material 40, the entire gap in the internal space 11 can be stably sealed, and the heat slug 20 and the leads 31, 32 can be stably fixed.

Moreover, if white highly reflective glass is used as the insulating material 40, the reflectance of a reflector can also be raised.
(Modification)
In the optical element package 1, one heat slug 20 is arranged in the internal space 11 of the base 10 and one optical element 50 is mounted. However, a plurality of heat slugs are installed in the internal space 11 of the base 10. 20 may be arranged and a plurality of optical elements 50 may be mounted.

FIG. 8 is a drawing showing an optical element package according to such a modification, wherein (a) is a plan view, (b) is a bottom view, and (c) is a cross-sectional view. In this figure, an optical element 50 mounted on an optical element package and wire-bonded is shown.
In this optical element package, two heat slugs 20 are vertically arranged in the internal space 11 of the base 10, and the optical element 50 is mounted on each heat slug 20. Here, since the two heat slugs 20 are arranged at intervals, the optical element 50 mounted on each heat slug 20 is not electrically short-circuited.

In the internal space 11, the pair of leads 31 and 32 are disposed so as to penetrate both sides of the heat slug 20.
Each optical element 50 is connected to the pair of leads 31 and 32 by wires 51 and 52.
In addition, the number and arrangement | positioning form of the heat slag 20 arrange | positioned in the internal space 11 of the base 10 can be set freely, for example, arranges four heat slags 20 in 2 rows and 2 columns, or 8 pieces. The heat slugs 20 may be arranged in four rows and two columns.

As described above, when a plurality of heat slugs 20 are disposed, optical elements having the same light emission color may be mounted on the plurality of heat slugs 20, but optical elements having different light emission colors may be mixed and mounted. For example, white light can be emitted as a whole by mixing optical elements of RGB colors.
In the optical element package 1, a pair of leads 31 and 32 are provided. However, if the heat slug 20 itself also serves as a terminal, only one lead may be provided.

The present invention can be applied to a package for an optical element that packages an optical element such as a light emitting diode (LED), and can be used for an illumination device by forming an optical semiconductor element.
Particularly, since the heat dissipation is good, it is suitable for an optical semiconductor element for high power.

It is the top view and bottom view of the package for optical elements which concerns on embodiment. FIG. 2 is a cross-sectional view taken along line A-A ′ in FIG. 1. It is a figure which shows a mode that the semiconductor light-emitting device which mounted the optical element in the said package for optical elements, and this mounted on a mounting substrate. It is a process flowchart which shows the manufacturing method of the package for optical elements, and a semiconductor light-emitting device. It is a figure which shows the metal plate material before bending a lead | read | reed. It is a figure which shows a glass sealing process. It is a figure which shows the process of producing a semiconductor light-emitting device. It is a figure which shows the package for optical elements which concerns on a modification. It is a characteristic view which shows the reflectance of the highly reflective alumina and Ag plating layer with respect to the light of each wavelength. It is a figure which shows the package for optical elements which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Package for optical elements 2 Semiconductor light-emitting device 3 Mounting board 10 Base 11 Internal space 11a Inner peripheral surface 11b Mating recessed part 12 Outer peripheral part 13 Inclined surface 14 Concave surface 15 Outer peripheral part 20 Heat slug 21 Mount part 31, 32 Lead 21a Side wall 21b Mating convex Part 22 Hanging part 22a Peripheral surface 22b Bottom surface 31, 32 Lead 31a, 32a Lead upper end part 31b, 32b Through part 31c, 32c Extension part 31d, 32d Termination part 31e, 32e Opening part 31f, 32f Projection part 32g, 32g Projection part
40 Insulating material 50 Optical element 51, 52 Wire

Claims (17)

An optical element package for packaging an optical element,
A ring-shaped base made of ceramic material;
A heat slag disposed in an internal space surrounded by the ring-shaped base with a gap between the inner peripheral surface of the base, and
An insulating material filled in the gap;
A lead that penetrates the insulating material and is inserted from the outside to the inside of the package,
The outer insulating material side of the lead is bent in the direction of the outer edge of the base and extends along the bottom surface of the base,
The heat slug has a top surface on the inner side of the package and a bottom surface on the outer side. The upper surface is exposed to the inside of the package and is used as a mounting portion for mounting an optical element. An optical device package, characterized by being exposed to   2. The optical element package according to claim 1, wherein the heat slag is made of oxygen-free copper or a copper alloy.   3. The optical element package according to claim 1, wherein the heat slug has a shape in which a mount portion is widened with respect to a hanging portion. 4. The portion of the heat slag that is suspended is
The optical element package according to any one of claims 1 to 3, wherein a cross-sectional shape differs depending on a position in a hanging direction.   5. The optical element package according to claim 1, wherein a bottom surface of the heat slug and a surface of a portion extending along a base bottom surface of the lead are on the same plane. On the outer periphery of the heat slag and the inner peripheral surface of the base,
The optical element package according to any one of claims 1 to 5, wherein a fitting portion for fitting each other is formed. The lead is
The position of the penetrating portion penetrating through the gap is offset to the base inner peripheral surface side from the outer periphery of the heat slag,
The optical element package according to claim 1, wherein an end portion close to the mount portion is bent toward the heat slug side. The outer periphery of the base is
The optical element package according to claim 1, wherein the optical element package is formed higher than the mount portion. The base is
9. The optical element package according to claim 1, wherein the optical element package is made of white highly reflective alumina having a reflectance of 85% or more for light having a wavelength of 450 nm.   The electronic component package according to claim 1, wherein the insulating material is made of white highly reflective glass.   The package for an optical element according to any one of claims 1 to 10, wherein the extended portion of the lead extends to the outside of the outer edge of the base, and a terminal portion thereof is bent upward.   12. The optical element package according to claim 11, wherein the lead insertion portion and the terminal end portion sandwich the bottom portion of the base.   The optical element package according to claim 1, wherein the insulating material is made of soda glass or borosilicate glass.   14. The optical element package according to claim 1, wherein the lead is made of an iron-nickel alloy system. The heat slug is
The optical element package according to claim 1, wherein a plurality of the optical element packages are provided. In the package for optical elements according to any one of claims 1 to 15,
A semiconductor light-emitting device in which an optical element is mounted and the optical element and a lead are wire-bonded. A semiconductor light-emitting device according to claim 16
An illumination device mounted on a substrate provided with wiring connected to a drive circuit.

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