JP4132043B2 - Light emitting element storage package and light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light-emitting element housing package for housing a light-emitting element, which is used in a display device using a light-emitting element such as a light-emitting diode.
[0002]
[Prior art]
Conventionally, a ceramic package has been used as a light-emitting element storage package (hereinafter also referred to as a package) for storing light-emitting elements such as light-emitting diodes, and an example thereof is shown in FIG. Reference 1). As shown in the figure, the conventional package is for mounting the light emitting element 13 on the bottom surface of the recess 14 of the substantially rectangular parallelepiped insulating base in which a plurality of ceramic layers are laminated and the recess 14 is formed on the upper surface. A base body 11 provided with a mounting portion 12 made of a conductor layer, and a pair of wiring layers 15 electrically connected from the mounting portion 12 of the base body 11 and its periphery to an external terminal conductor layer 18 formed on the lower surface of the base body 11 And is composed mainly of.
[0003]
Then, the light emitting element 13 is placed and fixed on the mounting portion 12 to which one end of one wiring layer 15 is electrically connected via a conductive adhesive, solder, etc., and the electrode of the light emitting element 13 and the other wiring The conductor 15 is electrically connected via the bonding wire 16, and then the light emitting device 13 is sealed by filling the recess 14 of the base 11 with a transparent resin (not shown) and sealing the light emitting element 13. .
[0004]
Further, in order to reflect the light of the light emitting element 13 on the inner surface of the recess 14 and to emit light above the package, the metallization having a nickel (Ni) plating layer or a gold (Au) plating layer on the inner surface of the recess 14 on the surface. A metal layer 17 composed of layers may be applied.
[0005]
[Patent Document 1]
JP 2002-232017 Gazette [0006]
[Problems to be solved by the invention]
However, in the conventional package described above, the package is firmly bonded to the external electric circuit board or peeled off from the portion where the metallized layer or the plating layer forming the metal layer 17 in the recess 14 is deposited by the heat generation of the light emitting element 13. As a configuration to effectively prevent this, the external terminal conductor layer 18 is formed in a wide area on the lower surface of the base 11 to increase the bonding area with the external electric circuit board and to provide good thermal conductivity, However, the space between the external terminal conductor layers 18 formed on the lower surface of the insulating base is narrowed with the recent downsizing of the package, and the external terminal conductor layer is reduced. There is a problem that the risk of short-circuiting the external terminal conductor layer 18 increases due to misalignment or bleeding during printing of 18 or short-circuiting of solder or the like when connecting the wiring layer 15 to the external electric circuit board. Which was.
[0007]
Therefore, the present invention has been completed in view of the above-described conventional problems, and the object thereof is to efficiently dissipate heat generated by the light emitting element to the outside of the package, and a plurality of external terminal conductor layers are short-circuited. It is an object of the present invention to provide a light-emitting element storage package that can effectively prevent this from occurring and can be firmly connected to an external electric circuit board.
[0008]
[Means for Solving the Problems]
The light emitting element storage package of the present invention includes an insulating base having a region on which the light emitting element is to be mounted on the upper surface, a wiring layer provided on the upper surface of the insulating base, a lower surface of the insulating base, and the wiring layer A plurality of electrically connected external terminal conductor layers, and the lower surface of the insulating base extends from one side of the insulating base to the opposite side between the external terminal conductive layers. A groove-like recess having an open end is formed.
[0009]
According to the light emitting element storage package of the present invention, the groove-like recesses having the open ends on both side surfaces are formed between the external terminal conductor layers on the lower surface of the insulating base from one side to the opposite side. In addition, air can pass through the groove-shaped concave portion provided on the lower surface of the insulating base, so that the heat dissipation of the insulating base can be enhanced and the external terminal conductor layers can be effectively prevented from being short-circuited. Can do. As a result, the external terminal conductor layer can be reliably formed in a wide area on the lower surface of the insulating base, and the external terminal conductor layer and the external electric circuit board can be firmly connected, The dispersibility can be further improved.
[0010]
The light emitting element storage package of the present invention is preferably characterized in that a plurality of the groove-like recesses are formed.
[0011]
Since the light emitting element storage package of the present invention is preferably formed with a plurality of groove-shaped recesses, the surface area of the groove-shaped recesses is increased, and the heat dissipation of the insulating substrate is further improved.
[0012]
The light-emitting device of the present invention includes the light-emitting element storage package of the present invention, a light-emitting element mounted on the mounting portion, and a transparent resin that covers the light-emitting element.
[0013]
The light-emitting device of the present invention has high performance and high reliability, which has high heat dissipation and can reliably prevent a short circuit between the outer terminal conductor layers.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The light emitting element storage package of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an example of an embodiment of a package of the present invention, in which 1 is an insulating substrate, 2 is a mounting portion of a light emitting element 3, 3 is a light emitting element, and 4 is a light emitting element 3. It is a recessed part for accommodating.
[0015]
In the package of the present invention, a recess 4 for accommodating the light emitting element 3 is provided on the upper surface of the insulating substrate 1, and the mounting portion 2 on which the light emitting element 3 is mounted and the electrode of the light emitting element 3 are connected to the bottom surface of the recess 4. The wiring layers 5a and 5b are formed, and a plurality of external terminal conductor layers 8a and 8b electrically connected to the wiring layers 5a and 5b are formed on the lower surface of the insulating base 1, respectively. Between the external terminal conductor layers 8a and 8b on the lower surface of 1 is formed a groove-like recess 9 having open ends on both side surfaces from one side surface to the opposite side surface.
[0016]
The insulating substrate 1 of the present invention is made of ceramics or resin, and when made of ceramics, for example, aluminum oxide sintered body (alumina ceramics), aluminum nitride sintered body, mullite sintered body, glass ceramic sintered body, etc. The insulating layer made of the above ceramics has a substantially square box shape, and a recess 4 for accommodating the light emitting element 3 is formed at the center of the upper surface. When the insulating substrate 1 is made of, for example, an aluminum oxide sintered body, an appropriate organic binder, solvent, etc. are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide to form a slurry. A green sheet (ceramic raw sheet) is obtained by forming into a sheet shape by a conventionally known doctor blade method or calendar roll method, and then a through hole for the recess 4 is formed in the green sheet by punching and a light emitting element A plurality of green sheets for mounting 3 and green sheets for the recesses 4 are stacked, fired at a high temperature (about 1600 ° C.), and integrated.
[0017]
Further, a mounting portion 2 for mounting the light emitting element 3 is formed on the bottom surface of the concave portion 4, and the mounting portion 2 is made of tungsten (W), molybdenum (Mo), copper (Cu), silver (Ag), or the like. It consists of a metallized layer of metal powder.
[0018]
Also, the insulating base 1 is formed by adhering wiring layers 5a and 5b electrically connected to the external terminal conductor layers 8a and 8b formed on the lower surface of the insulating base 1 from the mounting portion 2 and its periphery. The wiring layers 5a and 5b and the external terminal conductor layers 8a and 8b are made of a metallized layer of metal powder such as W or Mo, and are conductive paths for electrically connecting the light emitting element 3 housed in the recess 4 to the outside. . A light emitting element 3 such as a light emitting diode or a semiconductor laser is fixed to the mounting portion 2 with a conductive bonding material such as gold (Au) -silicon (Si) alloy or Ag-epoxy resin, and the wiring layer 5b The electrodes of the light emitting element 3 are electrically connected via bonding wires 6. The external terminal conductor layers 8a and 8b on the lower surface of the base 1 are connected to the respective wiring electrodes of the light emitting element 3 by being connected to the wiring conductors of the external electric circuit board, and power and driving signals are supplied to the light emitting element 3. Is done. The light emitting element 3 may be connected to the mounting portion 2 and the wiring layer 5b by flip chip mounting.
[0019]
The wiring layers 5a and 5b and the external terminal conductor layers 8a and 8b are preliminarily screen-printed on a green sheet serving as the base 1 with a metal paste obtained by adding and mixing an appropriate organic solvent and solvent to a metal powder such as W or Mo. By printing and applying to a predetermined pattern by the method, it is deposited on a predetermined position of the substrate 1.
[0020]
In addition, a metal having excellent corrosion resistance such as nickel (Ni), gold (Au), Ag or the like is formed on the exposed surfaces of the wiring layers 5a and 5b, the mounting portion 2, and the external terminal conductor layers 8a and 8b to a thickness of about 1 to 20 μm. The wiring layers 5a and 5b, the mounting portion 2, and the external terminal conductor layers 8a and 8b can be effectively prevented from being oxidized and corroded, and the mounting portion 2 and the light-emitting element 3 can be firmly fixed. The bonding between the wiring layers 5a and 5b and the bonding wire 6 and the bonding between the external terminal conductor layers 8a and 8b and the wiring conductor of the external electric circuit board can be strengthened. Therefore, on the exposed surfaces of the wiring layer 5b, the mounting portion 2, and the external terminal conductor layers 8a and 8b, there are an Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer or an Ag plating layer having a thickness of about 0.1 to 3 μm. More preferably, the electrodes are sequentially deposited by electrolytic plating or electroless plating.
[0021]
In addition, it is preferable that a metal layer 7 on which a metallized metal layer and a plating metal layer having a reflectance of 80% or more with respect to light emitted from the light emitting element 3 are deposited is formed on the inner peripheral surface of the recess 4. The metal layer 8 is formed by, for example, depositing a plated metal layer such as Ni, Au, or Ag on a metallized metal layer made of W, Mo, or the like. % Or more. When the reflectance with respect to the light emitted from the light emitting element 3 is less than 80%, it becomes difficult to favorably reflect the light emitted from the light emitting element 3 accommodated in the recess 4.
[0022]
Moreover, it is preferable that the inner peripheral surface of the recessed part 4 is an inclined surface, and spreads outward at an angle of 35 to 70 ° from the bottom surface of the recessed part 4 toward the upper surface of the insulating base. If the angle θ exceeds 70 °, it tends to be difficult to favorably reflect the light emitted by the light emitting element 3 accommodated in the recess 4 to the outside. On the other hand, when the angle θ is less than 35 °, it tends to be difficult to stably and efficiently form the inner peripheral surface of the recess 4 at such an angle, and the package becomes large.
[0023]
Moreover, as for the arithmetic mean roughness of the surface of the metal layer 7 of the inner peripheral surface of the recessed part 4, Ra has preferable 1-3 micrometers. If it is less than 1 μm, it becomes difficult to uniformly reflect the light emitted by the light emitting element 3 accommodated in the recess 4, and the intensity of the reflected light tends to be biased. If it exceeds 3 μm, the light emitted from the light emitting element 3 accommodated in the recess 4 is scattered, and it becomes difficult to uniformly radiate the reflected light to the outside with high reflectivity.
[0024]
Moreover, it is preferable that the cross-sectional shape of the recessed part 4 is circular. In this case, the light emitted from the light emitting element 3 accommodated in the recess 4 can be uniformly reflected in all directions by the metal plating layer on the surface of the metal layer 7 on the inner surface of the recess 4 and can be radiated to the outside very uniformly. There is.
[0025]
The external terminal conductor layers 8a and 8b preferably have an area of 15% or more with respect to the lower surface of the insulating base 1, and a flatness of the surface of 20 μm / 10 mm or less. If the area is less than 15%, the flatness of the external terminal conductor layers 8a and 8b is likely to be deteriorated, and the strength of the connection with the wiring conductor of the external electric circuit board is liable to be reduced, and if it exceeds 20 μm / 10 mm. When connecting to the wiring conductor of the external electric circuit board via solder, a variation in height occurs between the external terminal conductor layers 8a and 8b, and the external terminal conductor layers 8a and 8b are connected to the wiring conductor of the external electric circuit board. It becomes difficult to mount at the exact position.
[0026]
Further, the external terminal conductor layers 8a and 8b extend to the side surface of the insulating base 1, or form notches on the corners and side surfaces of the insulating base 1 to extend to the side surfaces of the notches. Also good. In this case, since the bonding area of the external electric circuit board with the wiring conductor can be increased, the connectivity between the external terminal conductor layers 8a and 8b and the external electric circuit board can be improved. Further, the external terminal conductor layers 8 a and 8 b may have different areas on the lower surface of the base 1.
[0027]
In the present invention, a groove-shaped recess 9 having open ends on both side surfaces is formed between one side surface of the insulating substrate 1 and the opposite side surface between the external terminal conductor layers 8 a and 8 b on the lower surface of the insulating substrate 1. The groove-like recess 9 is preferably 10% or more deep from the bottom surface of the recess 4 of the insulating substrate 1 to the lower surface of the insulating substrate 1. If it is less than 10%, the effect of heat dissipation becomes small. If the thickness from the bottom surface of the recess 4 of the insulating substrate 1 to the lower surface of the insulating substrate 1 is increased in order to enhance heat dissipation, the package will be enlarged.
[0028]
Moreover, the recessed part 9 may penetrate the bottom face of the recessed part 4 in order to improve heat dissipation. In this case, the insulating substrate 1 is divided at a portion below the bottom surface of the recess 4, but is integrally formed by joining at the frame-shaped portion of the recess 4.
[0029]
The concave portion 9 is formed at a substantially central portion between the external terminal conductor layers 8a and 8b, and the width of the concave portion 9 is 10 times the width of the lower surface of the insulating substrate 1 in the direction perpendicular to the longitudinal direction of the groove-shaped concave portion 9. It is preferably ˜50%. If it exceeds 50%, the formation region of the external terminal conductor layers 8a and 8b on the lower surface of the insulating substrate 1 becomes narrow, and deformation is likely to occur in the firing process or the like. On the other hand, if it is less than 10%, the effect of heat dissipation and prevention of short-circuiting of the external short-circuit conductor layers 8a and 8b is reduced. If the width of the substrate 1 is increased in order to enhance the effect of preventing short circuit, the package will be enlarged.
[0030]
Further, by forming a metal layer such as a W metallized layer on the inner surface of the recess 9 or by providing a solder or brazing material after forming the metal layer, a metal layer or metal lump having a high thermal conductivity is provided in the recess 9. By providing, it is also possible to obtain high heat dissipation. In addition, if the metal layer or the metal block having high thermal conductivity is formed with unevenness or a fin-like fin or the like, the heat dissipation can be further improved.
[0031]
In the present invention, it is preferable that a plurality of groove-like recesses 9 are formed. In this case, the surface area of the recess 9 is increased and the heat dissipation is further improved. 5 to 10 show various examples of embodiments of a package in which a plurality of recesses 9 are formed. 5 and 6 show two recesses 9 formed. FIG. 7 shows a configuration in which the height of the convex portion 9 a between the groove-like concave portions 9 in the configuration of FIG. 5 is made smaller than the depth of the concave portion 9. In this case, since air can circulate between the two recesses 9, heat dissipation is further improved.
[0032]
Moreover, as shown in FIG. 8, the groove-shaped recessed part 9 may be connected in the center part. Moreover, the site | part which the groove-shaped recessed part 9 communicates may be formed other than a center part, and may be formed in multiple numbers. In this case, since air can circulate between the two recesses 9, heat dissipation is further improved.
[0033]
In FIG. 9, three groove-like recesses 9 are formed, the surface area of the recesses 9 is further increased, and the heat dissipation is further improved. FIG. 10 is an example in which the portion 9a between the recesses 9 is formed lower than the other portions in the configuration of FIG. The height of the convex portion 9 a between the groove-shaped concave portions 9 is made smaller than the depth of the concave portion 9. In this case, since air can flow between the three recesses 9, heat dissipation is further improved.
[0034]
The light emitting device of the present invention includes the package of the present invention, the light emitting element 3 mounted on the mounting portion 2, and a transparent resin such as a silicone resin that covers the light emitting element 3. As a result, the heat dissipation is high, and the high-performance and high-reliability can be obtained, which can surely prevent a short circuit between the external terminal conductor layers 8a and 8b. The transparent resin that covers the light emitting element 3 may cover only the light emitting element 3 and its periphery, or may fill the recess 4 to cover the light emitting element 3.
[0035]
It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, as shown in the cross-sectional view of the package in FIG. 11, the light emitting element 3 is directly mounted on the bottom surface of the recess 4 without forming the mounting portion 2 as a conductor layer, and the electrodes of the light emitting element 3 are electrically connected to the periphery thereof. Wiring layers 5a and 5b connected to the substrate may be formed. In this case, the light emitting element 3 is mounted on the mounting portion 2, and the electrode of the light emitting element 3 and the wiring layers 5a and 5b are electrically connected via the bonding wires 6a and 6b. Further, a plurality of light emitting elements 3 may be mounted, or a plurality of wiring layers may be formed.
[0036]
【The invention's effect】
The light emitting element storage package of the present invention is insulated by forming groove-shaped recesses having open ends on both side surfaces from one side surface to the opposite side surface between the external terminal conductor layers on the lower surface of the insulating substrate. Air can pass through the groove-like recesses provided on the lower surface of the base body, so that the heat dissipation of the insulating base body can be improved, and a plurality of external terminal conductor layers can be effectively prevented from being short-circuited. . As a result, the external terminal conductor layer can be reliably formed in a wide area on the lower surface of the insulating base, and the external terminal conductor layer and the external electric circuit board can be firmly connected, The dispersibility can be further improved.
[0037]
Since the light emitting element storage package of the present invention is preferably formed with a plurality of groove-shaped recesses, the surface area of the groove-shaped recesses is increased, and the heat dissipation of the insulating substrate is further improved.
[0038]
The light-emitting device of the present invention includes the light-emitting element storage package of the present invention, the light-emitting element mounted on the mounting portion, and the transparent resin covering the light-emitting element. High performance and high reliability can be surely prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a light-emitting element storage package according to the present invention.
2 is a bottom view of the light emitting element storage package of FIG. 1; FIG.
FIG. 3 is a cross-sectional view of a conventional light emitting element storage package.
4 is a bottom view of the light emitting element storage package of FIG. 3. FIG.
FIG. 5 is a cross-sectional view showing another example of the embodiment of the light emitting element storage package of the present invention.
6 is a bottom view of the light emitting element storage package of FIG. 5. FIG.
FIG. 7 is a cross-sectional view showing another example of the embodiment of the light emitting element storage package of the present invention.
FIG. 8 is a bottom view showing another example of the embodiment of the light emitting element storage package of the present invention.
FIG. 9 is a cross-sectional view showing another example of the embodiment of the light emitting element storage package of the present invention.
FIG. 10 is a cross-sectional view showing another example of the embodiment of the light emitting element storage package of the present invention.
FIG. 11 is a cross-sectional view showing another example of the embodiment of the light emitting element storage package of the present invention.
[Explanation of symbols]
1: Substrate 2: Mounting portion 3: Light emitting element 4: Recesses 5a, 5b: Wiring conductors 8a, 8b: External connection conductor layer 9: Groove-shaped recess

Claims (3)

An insulating base having a region on the top surface where the light emitting element is to be mounted;
A wiring layer provided on the upper surface of the insulating substrate;
A plurality of external terminal conductor layers provided on the lower surface of the insulating base and electrically connected to the wiring layer;
Comprising
The lower surface of the insulating base is characterized in that a groove-like recess having open ends on both side surfaces is formed between the external terminal conductor layers from one side to the opposite side. Light emitting element storage package. 2. The light emitting element storage package according to claim 1 , wherein a plurality of the groove-shaped recesses are formed on the lower surface of the insulating base . The light emitting element storage package according to claim 1 or 2,
A light emitting element mounted on the mounting portion;
A transparent resin covering the light emitting element ;
A light emitting device comprising:

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