WO2007049938A1

WO2007049938A1 - Electronic parts packages and method for forming a cavity thereof

Info

Publication number: WO2007049938A1
Application number: PCT/KR2006/004419
Authority: WO
Inventors: Young-Il Lee; Jong-Weon Park; Yun-Min Cho
Original assignee: Amosense Co., Ltd.
Priority date: 2005-10-28
Filing date: 2006-10-27
Publication date: 2007-05-03
Also published as: CN101322254B; CN101322254A; KR20070045655A; KR100719072B1

Abstract

Disclosed is an electronic part package for improving reflectability of light emitted from a light emitting device, and a method of forming a cavity of the electronic part package to improve the reflectability of light so that the cavity of a ceramic substrate is easily formed to have the desired shape. The cavity of the ceramic substrate has a shape tapered inward so that an inclined side is roundly concave and convex. The method includes shifting a tool that includes a cutting part having a cutting blade formed on an external surface thereof toward the ceramic substrate by a predetermined distance while the tool rotates along with a rotational processing part of a ceramic processing device and returning the tool to an original position of the tool to form a cavity having the inclined side in the ceramic substrate.

Description

ELECTRONIC PARTS PACKAGES AND METHOD FOR FORMING A CAVITY THEREOF

Technical Field

[1] The present invention relates to an electronic part package and a method of forming a cavity of the electronic part package. More particularly, the present invention pertains to an electronic part package that is provided to maximize emission efficiency of light emitted from a light emitting device and a method of forming a cavity in a ceramic substrate of the electronic part package through a simple procedure.

[2]

Background Art

[3] A light emission diode (hereinafter, referred to as an LED) is a semiconductor device that is capable of providing various types of colors. The LED includes a light emission source which is provided so that compound semiconductor materials such as GaAs, AlGaAs, GaN, InGaN, and AlGaInP are changed. Currently, the package type of semiconductor devices is applied to electronic parts.

[4] Generally, the criteria in determining the properties of LED devices are the color, luminance, and the intensity range of luminance. The properties of the LED devices are determined by the compound semiconductor material that is used in the LED device. Furthermore, the properties are significantly affected by the structure of the package on which chips are to be mounted.

[5] With reference to FIG. 1, package structures of a lamp type of LED and a surface mount type of LED are compared to each other. A lamp type of an LED package 10 that is shown in FIG. IA includes two lead frames 3a and 3b. A metal electrode having a cup shape is formed over the lead frame 3b. An LED device 5 is mounted on an upper part of the lead frame 3b. The lamp type of an LED package 10 has a structure in which the packaging is performed using a hemispheric case 7 made of transparent molding resins.

[6] Meanwhile, the surface mount type of LED package 20 that is shown in FIG. IB is provided with a package body 11 that is formed of a molding epoxy resin. The package body 11 includes a cavity having a predetermined inclination angle. The cavity is formed to correspond to a position of a mounting region of a light emitting device on which an LED device 15 is to be mounted. The LED device 15 is mounted on the mounting region of the light emitting device of the package body 11. The LED device 15 is connected by wires 13 to a pattern electrode (not shown).

[7] In the lamp type of LED package 10, the hemispheric case 7 acts as a lens to control distribution of luminance. Particularly, the distribution of the luminance is controlled to be narrow so as to increase the luminance at a predetermined angle and to reflect light emitted from the light emitting source on the metal electrode, thereby increasing the luminance.

[8] However, in the surface mount type of LED package 20, the wide luminance distribution is assured due to the package, and the luminance is low. As described above, the luminance and the luminance distribution are significantly affected by the package structure. Accordingly, in the surface mount type of LED package using the molding resins, if the high output LED device is used to increase the luminance, since the thermal conductivity of the molding resins is very low, the quantity of emitted heat is increased, thus negatively affecting the package. In the case of when the high output LED device is mounted to increase the luminance, the ceramic substrate having the thermal conductivity that is higher than that of the molding resin is used as the substrate for package.

[9] However, in the LED package using the ceramic substrate, it is difficult to assure the luminance and the luminance distribution that are the same as those of the surface mount type of LED package using the molding resin. That is, an injection molding process such as the molding of the resin cannot be applied to the ceramic substrate due to the properties of the material of the ceramic substrate. The ceramic substrate is formed using a punching process, a layering process, or a cutting process. Typically, since the mounting region of the light emitting device of the ceramic substrate is formed using the punching to have a groove shape, it is difficult to form a lateral side of the mounting region of the light emitting device having a predetermined reflection angle. A description regarding this will be given with reference to FIG. 2.

[10] FIG. 2 is a sectional view of a known LED package formed using a ceramic substrate. An LED package 30 is formed of two ceramic substrates 21 and 22 that each have a structure where a plurality of ceramic sheets are layered. The ceramic substrate

21 that is disposed at a lower part of the LED package has a mounting region on which an LED device 25 is to be mounted at an upper side thereof. Electrodes 23 that are connected by wires 27 to the LED device 25 extend from the mounting region through both sides of the LED package to a lower side of the package. The ceramic substrate

22 that is disposed at an upper part of the LED package has a predetermined cavity to surround the mounting region of the LED device 25.

[11] In connection with this, since the cavity for the mounting region of the LED device

25 is formed using the punching process or the cutting process, the section of the cavity is vertically formed as shown in the drawing. Due to the above-mentioned characteristics, since the sectional view of the cavity is vertically formed unlike the package that is formed using the molding resins, there is a problem in that it is impossible to form the excellent reflection film.

[12] As a result, in the LED package using the ceramic substrate, adjustment can only be performed by controlling the area of the mounting region of the LED device and the height of the substrate constituting walls of the LED package. Accordingly, it is difficult to produce the LED package having the luminance and the luminance angular distribution which are capable of satisfying various types of needs for users.

[13] However, the ceramic substrate is excellent in terms of thermal conductivity and heat emission. Therefore, it is possible to avoid problems including reduced performance of the device or heat stress of the resin due to heat emitted from the LED device. In the related art, there was a strong need to produce the semiconductor package for light emission diodes where the ceramic substrate having the excellent thermal conductivity and heat emission is used as the substrate for package and a difficulty in adjustment of the luminance and the luminance angular distribution due to the vertical structure necessarily required in the production process is avoided.

[14] Therefore, as shown in FIG. 3, an LED package where a cavity is formed to be tapered in a ceramic substrate has been suggested.

[15] The LED package of FIG. 3 is provided with a chip type of LED device 32; a lower ceramic substrate 35 on which the LED device 32 is to be mounted; an upper ceramic substrate 40 which is disposed on the lower ceramic substrate 35 and in which a cavity is formed to be inclined at a predetermined inclination angle in a region corresponding to a position of the region on which the LED device 32 is to be mounted; pattern electrodes (an anode electrode 34 and a cathode electrode 36) that are formed on the lower ceramic substrate 30; and a reflection plate (also called a reflection film) 44 that is provided on a lateral side of the cavity of the upper ceramic substrate 40 to surround the LED device 32. A hanging part 44a is formed at an upper end of the reflection plate 44 to hang on the upper side of the upper ceramic substrate 40.

[16] In the LED package of FIG. 3, the inclined cavity is formed in the upper ceramic substrate 40 to improve the luminance and to control the luminance angular distribution. In order to control the various types of directional angles and the luminance, it is necessary to modify simply the inclined side (internal side) of the cavity to have the desired shape. However, in the LED package of FIG. 3, since the inclined side of the cavity is flat, the degree of freedom is reduced. Accordingly, it is difficult to control the various types of directional angles and the luminance. Since it is required that the inclined side (internal side) of the cavity of the upper ceramic substrate 40 of FIG. 3 is evenly formed, the following problems may occur.

[17] In order to form the cavity in the upper ceramic substrate 40 of FIG. 3, typically, a powder process in which powder (ceramic powder) is put on a press to perform the shaping is used. [18] Meanwhile, another process of forming the cavity in the upper ceramic substrate 40 is shown in FIG. 4. That is, as shown in FIG. 4A, a plurality of ceramic sheets (also referred as the green sheet) 51 to 58 that include holes having different diameters at the centers thereof are layered on the lower ceramic substrate 35. Subsequently, as shown in FIG. 4B, a jig 60 is pressed to move toward the holes formed in a plurality of ceramic sheets 51 to 58 that are layered. Thereby, the structure of FIG. 4C is obtained. Next, if the jig 60 is vertically pulled upward, the upper ceramic substrate 40 has the cavity with the inclined internal side.

[19] Still another process of forming the cavity in the upper ceramic substrate 40 is shown in FIG. 5. That is, as shown in FIG. 5A, a plurality of ceramic sheets 51 to 58 that include holes having different diameters at the centers thereof are layered on the lower ceramic substrate 35. Subsequently, as shown in FIG. 5B, metal or a dielectric paste 62 is charged on step portions and then sintered. After the sintering is finished, the upper ceramic substrate 40 has the cavity with the inclined internal side.

[20]

Disclosure of Invention Technical Problem

[21] However, the above-mentioned processes in which the cavity is formed in the upper ceramic substrate have the following problems.

[22] First, in the process shown in FIG. 3, it is very difficult to produce a mold used to shape powder. Furthermore, a tolerance in dimension is formed due to a difference in the contraction ratio during sintering according to a change of the physical properties of the powder. In the case of when the change of the physical properties of the powder is significant in the course of avoiding the tolerance in dimension, there is a problem in that it is necessary to produce a novel mold. In order to obtain the desired directional angle and luminance, in the case of when the inclined side of the cavity is not processed flat but processed round, there is a problem in that it is necessary to separately produce a costly press.

[23] Second, in the process shown in FIG. 4, it is necessary to form the holes having the different diameters in the layers to perform the layering through multi-steps. During the layering, since the central axes are shifted due to the tolerance, the shape of the holes may be deformed. After the pressing is performed using the jig or during sintering, a difference in contraction ratio occurs resulting from a difference in density of the ceramics at the step portions which are pressed by the jig. Accordingly, the process is disadvantageous in that the inclined side is curved. In order to obtain the desired directional angle and luminance, in the case of when the inclined side of the cavity is not processed flat but processed round, there is a problem in that it is necessary to produce an additional jig.

[24] Third, in the process shown in FIG. 5, the shape of the holes may be deformed due to the tolerance during the layering through the multi-steps like the problem of the second process. Furthermore, the process is disadvantageous in that the inclined side of the cavity is curved due to a difference in contraction ratio of the metal or the dielectric paste which is discharged during the sintering to the ceramic material. In order to obtain the desired directional angle and luminance, in the case of when the inclined side of the cavity is not processed flat but processed round, it is difficult to appropriately fill the metal or the dielectric paste.

[25] The present invention has been made to avoid the above problems occurring in the related art, and an object of the present invention is to provide an electronic part package for improving reflectability of light emitted from a light emitting device.

[26] Another object of the present invention is to provide a method of forming a cavity of an electronic part package to improve reflectability of light emitted from a light emitting device so that the cavity of a ceramic substrate is easily formed to have the desired shape.

[27] Still another object of the present invention is to provide an electronic part package that quickly emits heat generated incidentally from a light emitting device.

[28]

Technical Solution

[29] In order to accomplish the above object, an electronic part package according to an embodiment of the present invention includes a lower ceramic substrate on which a mounting region of a light emitting device is formed, and an upper ceramic substrate which is disposed on the lower ceramic substrate and has a cavity formed in a region corresponding to the mounting region of the light emitting device where a cavity is formed. The cavity has a shape tapered inward so that an inclined side is roundly concave and convex.

[30] A reflection plate is formed on the inclined side. The reflection plate is connected to a second pattern electrode which is formed on an upper side of a lower ceramic substrate to be spaced apart from a first pattern electrode formed in a mounting region of a light emitting device.

[31] In detail, the inclined side is roundly convex in a range from an uppermost portion thereof to a lower point that is apart from the uppermost portion by a predetermined distance, and is roundly concave in a range from a lowermost portion of the convex side to a lowermost portion thereof. On the other hand, the inclined side may be roundly concave in a range from an uppermost portion thereof to a lower point that is apart from the uppermost portion by a predetermined distance, and is roundly convex in a range from a lowermost portion of the concave side to a lowermost portion thereof.

[32] A cavity is formed in a lower side of the lower ceramic substrate. A thermal via body is interposed between the cavity formed in the lower side of the lower ceramic substrate and a pattern electrode formed in the mounting region of the light emitting device.

[33] A first pattern electrode that is electrically connected to at least one of the pattern electrodes formed on an upper side of the lower ceramic substrate, a second pattern electrode that is formed in the mounting region of the light emitting device and is electrically connected to the pattern electrode covering an upper side of the thermal via body, and a metal member that covers an internal lateral surface of the cavity of the lower ceramic substrate, is connected to a lower side of the thermal via body, and is spaced apart from the first and the second pattern electrodes are formed on the lower side of the lower ceramic substrate.

[34] A thermal conductive medium fills the cavity formed in the lower side of the lower ceramic substrate.

[35] A method of forming a cavity in a ceramic substrate of an electronic part package according to the embodiment of the present invention includes a first step of removably providing a tool that includes a cutting part having a cutting blade formed on an external surface thereof in a rotational processing part of a ceramic processing device, and a second step of shifting the tool toward the ceramic substrate by a predetermined distance while the tool rotates along with the rotational processing part and returning the tool to an original position of the tool to form a cavity having an inclined side in the ceramic substrate.

[36] The cutting part is longitudinally tapered.

[37] The cutting part may longitudinally taper to have a round longitudinal end.

[38] The cutting part may longitudinally taper to have a round longitudinal end and protrusions formed on the longitudinal end.

[39] The cutting part may longitudinally taper to have teeth on an edge of a longitudinal end thereof. A flat portion may be formed at the center of the edge of the longitudinal end.

[40] A length of the cutting part is greater than or identical to a depth of the cavity formed in the ceramic substrate.

[41]

Advantageous Effects

[42] According to the present invention, since a cavity having a desired shape is formed in a ceramic sheet by means of a tool (jig) for forming various types of inclined sides using a simple process, it is possible to easily form the cavity having the desired shape.

Accordingly, it is possible to simply control directional angles and luminances. [43] Since an internal side of a cavity of a ceramic substrate may not be flat but uneven with a combination of concave and convex, it is possible to reflect light emitted from an LED device in a desired direction. Thus, it is possible to maximize emission efficiency of light. [44] Heat generated from the LED device is emitted through an anode, a reflection plate, a cathode, and a thermal via body to minimize thermal stress of the LED device. Accordingly, it is possible to stably operate the LED device.

[45] Unlike the known art, it is unnecessary to produce an additional mold, and deformation of the cavity due to the tolerance during the layering through the multi-steps does not occur. [46]

Brief Description of the Drawings [47] FIG. 1 illustrates a known LED package;

[48] FIG. 2 is a sectional view of a known LED package using a ceramic substrate;

[49] FIG. 3 is a sectional view of another known LED package using a ceramic substrate; [50] FIG. 4 illustrates sectional views showing a process of forming a cavity of the upper ceramic substrate of FIG. 3; [51] FIG. 5 illustrates sectional views showing another process of forming a cavity of the upper ceramic substrate of FIG. 3; [52] FIG. 6 is a sectional view of an electronic part package according to a first embodiment of the present invention; [53] FIG. 7 is a sectional view of an electronic part package according to a second embodiment of the present invention; [54] FIG. 8 is a sectional view of an electronic part package according to a third embodiment of the present invention; [55] FIG. 9 illustrates the formation of a cavity of the electronic part package according to the first embodiment of the present invention; [56] FIG. 10 is a partial sectional view showing an inclined side forming tool of FIG. 9 which is provided in a ceramic processing device; [57] FIG. 11 illustrates the formation of a cavity of an electronic part package according to the second embodiment of the present invention; [58] FIG. 12 illustrates the formation of a cavity of an electronic part package according to the third embodiment of the present invention; [59] FIG. 13 illustrates the formation of a cavity of an electronic part package according to a fourth embodiment of the present invention;

[60] FIG. 14 illustrates the formation of a cavity of an electronic part package according to a fifth embodiment of the present invention;

[61] FIG. 15 illustrates the formation of a cavity of an electronic part package according to a sixth embodiment of the present invention; and

[62] FIG. 16 illustrates the formation of a cavity of an electronic part package according to a seventh embodiment of the present invention.

[63]

Mode for the Invention

[64] Hereinafter, a description will be given of an electronic part package and a method of forming a cavity of the electronic part package according to the present invention with reference to the accompanying drawings. Hereinafter, a semiconductor package to which a light emission diode is applied, that is, an LED package, will be described as the electronic part package.

[65] FIG. 6 is a sectional view of an electronic part package according to a first embodiment of the present invention.

[66] The LED package of FIG. 6 is provided with a chip type of LED device 62; a lower ceramic substrate 60 on which the LED device 62 is to be mounted; an upper ceramic substrate 70 which is disposed on the lower ceramic substrate 60 and in which a cavity having a predetermined shape is formed in a region corresponding in position to the region on which the LED device 62 is to be mounted; pattern electrodes 64 and 66 that are formed on the lower ceramic substrate 60; and a reflection plate (also called a reflection film) 74 that is provided on a lateral side of the cavity of the upper ceramic substrate 70 to surround the LED device 62. A hanging part 74a is formed at an upper end of the reflection plate 74 to hang on the upper side of the upper ceramic substrate 70.

[67] Particularly, the cavity of the upper ceramic substrate 70 has a shape tapered inward having an inclination angle (for example, 10° to 45°). A lateral surface of the cavity of the upper ceramic substrate 70 includes a concave portion and a convex portion that are combined with each other. That is, the lateral surface of the cavity of the upper ceramic substrate 70 is convex in the range from the uppermost portion of the lateral surface to a predetermined point that is apart from the uppermost portion by a predetermined distance (that is, the distance between the uppermost portion and the inflection point (a)). Additionally, the lateral surface is concave in the range from the lowermost portion of the convex surface to the lowermost portion of the whole lateral surface of the cavity of the upper ceramic substrate 70.

[68] Therefore, the reflection plate 74 that closely adheres to the lateral surface of the cavity of the upper ceramic substrate 70 has a convex portion and a concave portion to correspond to the shape to those of the lateral surface of the cavity. Additionally, the sizes of the round portions of the convex portion and the concave portion are set to maximumly reflect light emitted from the LED device 62.

[69] The sizes of the round portions of the convex portion and the concave portion are experimentally obtained. The convex portion and the concave portion of the reflection plate 74 that are obtained due to the shape of the cavity reflect light which is emitted from the LED device 62 frontward. Thereby, light emission efficiency of the LED package is maximized.

[70] Any substrate may be used as the lower ceramic substrate 60 as long as the LED device 62 is capable of being densely mounted on the substrate. For example, the lower ceramic substrate 60 may be formed of a material such as alumina, quartz, calcium zirconate, forsterite, SiC, graphite, fused silica, mullite, cordierite, zirconia, beryllia, aluminum nitride, LTCC (low temperature co-fired ceramic), and varistor material. The material of the lower ceramic substrate 60 is not limited. In FIG. 6, it seems that the lower ceramic substrate 60 is formed of the single ceramic sheet (green sheet). However, in practice, a plurality of ceramic sheets are layered to form the lower ceramic substrate 60.

[71] The upper ceramic substrate 70 may be formed of the same material as the lower ceramic substrate 60.

[72] The reflection plate 74 is connected to at least one (for example, the anode electrode

64) of the pattern electrodes that are formed on the lower ceramic substrate 60. A gap between a lower end of the reflection plate 74 and the anode electrode 64 is removed to minimize the loss of light emitted from the LED device 62.

[73] Preferably, the reflection plate 74 may be separately produced and then provided on the lateral surface of the cavity of the upper ceramic substrate 70 using a silicon-based bonding agent.

[74] Alternatively, a low temperature co-fired ceramic process may be used. In the case of when the low temperature co-fired ceramic process is used, after conductive metal such as Ag in the range of 2 to 20 microns is printed on a ceramic surface (that is, the lateral surface of the cavity of the upper ceramic substrate 70), sintering is performed using the low temperature co-fired ceramic process. After sintering, Ni in the range of 2 to 10 microns is plated on the sintered surface, and Ag (Au) in the range of 2 to 20 microns is additionally plated thereon. Thereby, the reflection plate 74 is formed on the lateral surface of the cavity of the upper ceramic substrate 70. During the sintering using the low temperature co-fired ceramic process, the temperature is increased from 25⁰C at a rate of 2°C/min. If the temperature reaches 830°C~900°C, the temperature is maintained for 20 min. The temperature is then reduced at a rate of 2°C/min. Next, if the temperature reaches 25⁰C, sintering is finished.

[75] The above-mentioned plating and sintering condition is typical, and may vary in terms of the composition and the additive.

[76] In FIG. 6, a hanging part 74a of the reflection plate 74 is hung on an upper side of the upper ceramic substrate 70. Thus, an area of the exposed hanging part 74a is increased to increase heat emission efficiency. The hanging part 74a may cover a whole upper surface of the upper ceramic substrate 70. The shape of the hanging part 74a may vary according to an appearance of a package main body and the heat emission efficiency. It is apparent that the modification of the hanging part 74a is possible in the range of the present invention.

[77] The above-mentioned reflection plate 74 may be used as a means for efficiently emitting heat of the LED device 62 through the hanging part 74a.

[78] The pattern electrodes 64 and 66 are formed of the anode electrode 64 and the cathode electrode 66 that are spaced apart from each other.

[79] The anode electrode 64 is formed on a left portion and a right portion of an upper side of the lower ceramic substrate 60. The anode electrode 64 is formed to be spaced apart from the cathode electrode 66 that is formed on the mounting region of the light emitting device of the lower ceramic substrate 60 (that is, the center of the upper side of the lower ceramic substrate 60) so that the anode electrode and the cathode electrode are electrically insulated. The anode electrode 64 is formed on a lower surface of the lower ceramic substrate 60. The anode electrode 64 that is formed on the lower surface of the lower ceramic substrate 60 may extend from the anode electrode 64 that is formed on the upper surface of the lower ceramic substrate 60. Meanwhile, the anode electrode 64 that is formed on the lower surface of the lower ceramic substrate 60 may be separated from the anode electrode 64 that is formed on the upper surface of the lower ceramic substrate 60 while electric connection is maintained.

[80] The cathode electrode 66 is provided on the mounting region of the light emitting device of the lower ceramic substrate 60. An end of the cathode electrode 66 is provided to be spaced apart from the anode electrode 64 by a predetermined distance, and extends to the lower surface of the lower ceramic substrate 60 so that the cathode electrode 66 is vertically formed through the body of the lower ceramic substrate 60 and closely adheres to the lower surface of the lower ceramic substrate 60.

[81] The LED device 62 is mounted on the cathode electrode 66. The LED device 62 is electrically connected by wires 72 to the anode electrode 64 and the cathode electrode 66. The LED device 62 is insulated from the cathode electrode 66 on which the LED device 62 is mounted by an insulating material. This is not shown.

[82] Needless to say, the anode electrode 64 may act as the cathode electrode and the cathode electrode 66 may act as the anode electrode. In this case, a driving power applying manner is reversed.

[83] FIG. 7 is a sectional view of an electronic part package according to a second embodiment of the present invention. The second embodiment is almost similar to the above-mentioned first embodiment (see FIG. 6).

[84] The second embodiment is different from the first embodiment in terms of the shapes of the cavity of the upper ceramic substrate 70 and the reflection plate 74 which closely adheres to the upper ceramic substrate. That is, the structure of the convex portion and the concave portion of the cavity of FIG. 6 is opposite to the structure of the convex portion and the concave portion of the cavity of FIG. 7. Accordingly, the structure of the convex portion and the concave portion of the reflection plate 74 of FIG. 6 is opposite to the structure of the convex portion and the concave portion of the reflection plate 74 of FIG. 7. The structure of the second embodiment is the same as the structure of the embodiment of FIG. 6, with the exception of the above-mentioned differences.

[85] The above-mentioned structure of the convex portion and the concave portion of the reflection plate 74 that is obtained due to the shape of the cavity maximumly reflects light that is emitted from the LED device 62 frontward. Accordingly, light emission efficiency of the LED package is maximized.

[86] FIG. 8 is a sectional view of an electronic part package according to a third embodiment of the present invention.

[87] In FIG. 8, the shape of the cavity of the upper ceramic substrate 70 and the shape of the reflection plate 74 are the same as those of the first embodiment (see FIG. 6). Of course, the shape of the cavity of the upper ceramic substrate 70 and the shape of the reflection plate 74 of FIG. 8 may be the same as those of the second embodiment (see FIG. 7).

[88] In FIG. 8, the constitution of the lower ceramic substrate 60 is different from the constitutions of the lower ceramic substrates 60 of the first embodiment and the second embodiment. Hereinafter, only the different constitution elements will be described.

[89] In FIG. 8, a cavity having a predetermined inclination angle (for example, 10° to

45°; the angle at which the heat emission is well performed) is formed on the lower surface of the lower ceramic substrate 60 (that is, the portion corresponding to a position of the mounting region of the light emitting device). The shape of the cavity that is formed on the lower surface of the lower ceramic substrate 60 may vary. However, it is preferable that the shape of the cavity be a tapering cylinder. Of course, in FIG. 8, the cavity may not be formed on the lower surface of the lower ceramic substrate 60. In the case of when the cavity is not formed, it is unnecessary to form the metal core 76. Instead, it is necessary to form the thermal via body 68 that extends to the lower surface of the lower ceramic substrate 60. [90] Meanwhile, a plurality of thermal via holes 80a, 80b, and 80c are formed through a portion between the mounting region of the light emitting device of the upper surface of the lower ceramic substrate 60 and the cavity in the lower side of the substrate. A plurality of thermal via holes 80a, 80b, and 80c are vertically formed while being spaced apart from each other. The thermal via bodies 68 (68a, 68b, 68c) that are formed of metal are plugged in a plurality of thermal via holes 80a, 80b, and 80c. A plurality of thermal via holes 80a, 80b, and 80c may be formed to have a circular, rectangular, or polygonal section.

[91] In FIG. 8, the three thermal via holes 80a, 80b, and 80c are formed. However, the number of the thermal via holes may be three or more, or can be unified as one. The central thermal via hole 80b of a plurality of thermal via holes 80a, 80b, and 80c has a diameter that is larger than or the same as the size of the LED device 62.

[92] The reason why the thermal via hole 80b having the diameter that is larger than or the same as the size of the LED device 62 is provided directly under the LED device 62 is as follows. The thermal via hole 80b is disposed at the position to which heat emitted from the LED device 62 is first applied in the greatest amount as compared to the other thermal via holes 80a and 80c. If heat generated from the LED device 62 is not efficiently emitted, the temperature of the LED device 62 is increased, causing deterioration. Accordingly, light emission efficiency is reduced, causing a reduced life span. Therefore, the diameter of the thermal via hole 80b is set to be larger than or the same as the size of the LED device 62. The diameter of each of the other thermal via holes 80a and 80c may be larger or smaller than the size of the LED device 62.

[93] For example, in the case of when a plurality of LED devices 62 are arrayed, the thermal via hole 80b and the thermal via body 68b are disposed directly under each of the LED devices 62. The above-mentioned thermal via holes 80a and 80c and the thermal via bodies 68a and 68c are disposed around the thermal via hole 80b and the thermal via body 68b to emit heat generated from the LED devices 62 therethrough.

[94] The anode electrode 64 that is one of the pattern electrodes is formed on the left portion and the right portion of the upper side of the lower ceramic substrate 60. The anode electrode 64 is formed to be spaced apart from the cathode electrode 66 that is formed on the mounting region of the light emitting device of the lower ceramic substrate 60 (that is, the center of the upper side of the lower ceramic substrate 60) so that the anode electrode and the cathode electrode are electrically insulated. The anode electrode 64 is formed to be spaced apart from the thermal via holes 80a and 80c. The anode electrode 64 is also formed on a lower surface of the lower ceramic substrate 60. The anode electrode 64 that is formed on the lower surface of the lower ceramic substrate 60 may extend from the anode electrode 64 that is formed on the upper surface of the lower ceramic substrate 60. Meanwhile, the anode electrode 64 that is formed on the lower surface of the lower ceramic substrate 60 may be separated from the anode electrode 64 that is formed on the upper surface of the lower ceramic substrate 60 while electric connection is maintained.

[95] The cathode electrode 66 that is another of the pattern electrodes covers upper openings of the thermal via holes 80a, 80b, and 80c in the mounting region of the light emitting device. An end of the cathode electrode 66 extends through the body of the lower ceramic substrate 60 to the lower surface of the lower ceramic substrate 60.

[96] A metal member 82 (also can be referred to as a metal film) closely adheres to the lateral surface of the cavity that is formed in the lower surface of the lower ceramic substrate 60. Both ends of the metal member 82 are spaced apart from the anode electrode 64 and the cathode electrode 66 that are provided on the lower surface of the lower ceramic substrate 60.

[97] A metal core 76 that is made of a conductive material such as Cu or Al fills the cavity that is formed in the lower surface of the lower ceramic substrate 60. The metal core 76 acts as a thermal sink. The reason why the metal member 82 covers the lateral surface of the cavity of the lower surface of the lower ceramic substrate 60 is as follows. If the metal core 76 is directly applied on the cavity that is formed of ceramic, attachment between the ceramic and the metal is poor. If the metal member 82 is formed on the lateral surface of the cavity which is to be filled with the metal core 76 in advance, the attachment of the metal core 76 may be improved.

[98] In the case of when the shape of the cavity that is formed in the lower surface of the lower ceramic substrate 60 is a tapering cylinder, for example, an inner diameter of the cavity is set to 1.0 mm or more, and an outer diameter of the cavity is set to 3.5 mm or less. This is data that is obtained with respect to the LED having the size of 5 * 5 mm. The shape and the size of the cavity that is formed in the lower surface of the lower ceramic substrate 60 vary according to the size of the LED device 62 to be mounted. With respect to the LED device 62 having the size of 3 * 3 mm, an inner diameter of the cavity which is formed in the lower surface of the lower ceramic substrate 60 may be set to 0.3 mm or more and an outer diameter of the cavity may be set to 2.0 mm or less so that the metal core 76 acts as the thermal sink.

[99] Meanwhile, the constitutional elements that perform heat emission in FIG. 8, that is, the thermal via holes 80a, 80b, and 80c, the thermal via body 68, and the metal core 76, may be applied to the LED packages of FIGS. 6 and 7.

[100] Hereinafter, a description will be given of a method of simply and reliably forming various types of cavities in the ceramic substrate. Accordingly, in the electronic part packages according to the first embodiment to the third embodiment of the present invention, the cavity of the upper ceramic substrate 70 may be formed through the following procedure. Of course, the method may be applied to the known structure of FIG. 3 to assure the following advantages.

[101] FIG. 9 illustrates the formation of the cavity of the electronic part package according to the first embodiment of the present invention. FIG. 10 is a partial sectional view showing an inclined side forming tool of FIG. 9 which is provided in a ceramic processing device.

[102] The inclined side forming tool 90 (see FIG. 9A) includes a cylindrical trunk part 92 and a conical cutting part 94. A cutting part 94 is formed at a lower portion of the trunk part 92. In other words, the cutting part 94 tapers at a lower portion thereof. A plurality of distorted cutting blades 96 are densely formed on a surface of the cutting part 94 at predetermined intervals. An upper portion of the trunk part 92 is inserted into a groove of a rotational processing part 91 (see FIG. 10) of a ceramic processing device (not shown), or comes from the groove of the rotational processing part. In order to insert the trunk part 92 or push the trunk part 92 from the groove, the groove of the rotational processing part 91 may be internally threaded and a surface of an upper portion of the trunk part 92 may be externally threaded. This is not shown.

[103] In the above-mentioned description, the trunk part 92 has the cylinder shape.

However, the shape of the trunk part may be a polyhedron such as a tetrahedron or a pentahedron, if necessary.

[104] The ceramic processing device, which is not shown, is a device for forming a hole that has an inclined side and a desired shape of a ceramic (or a ceramic sheet) using various types of inclined side forming tools. Typically, a program regarding operation is provided in the ceramic processing device. Additionally, an operation panel is provided in the ceramic processing device to perform operation by a worker.

[105] The rotational processing part 91 of the ceramic processing device is capable of rotating, ascending, and descending. The rotational processing part 91 may be manually operated or automatically operated by an automation program. The rotational processing part 91 rotates at a rate of, for example, 10000 to 30000 rpm.

[106] Hereinafter, a description will be given of a method of forming the cavity in the ceramic using the inclined side forming tool 90. It is considered that the ceramic processing device (not shown) is operated by the automation program. In connection with this, the term "cavity" is defined as a hole that is formed in the ceramic to have the inclined side and to surround the mounting region of the LED device. The above- mentioned definition of the cavity is applied to descriptions of other drawings.

[107] First, the upper portion of the trunk part 92 of the inclined side forming tool 90 is inserted into the groove of the rotational processing part 91 of the ceramic processing device. Next, the rotational processing part 91 and the trunk part 92 are firmly combined with each other by using the tightening part 93.

[108] Subsequently, if the ceramic processing device is turned on by the worker, the ceramic processing device is operated according to the automation program to form the hole in the ceramic. That is, the rotational processing part 91 which is combined with the inclined side forming tool 90 moves upward and downward with respect to the ceramic that is disposed under the inclined side forming tool while rotating. A hole 95a is formed in the ceramic 95 (see FIG. 9B) by a single reciprocation of descending and ascending. In other words, the inclined side forming tool 90 that protrudes downward from the rotational processing part 91 vertically descends while rotating in conjunction with the rotational processing part 91 that rotates at a high speed. If the descending is performed to some degree (that is, the inclined side forming tool descends to a predetermined distance), the cutting part 94 of the inclined side forming tool 90 comes into contact with the ceramic 95. At this time, the descending is slightly performed (that is, the inclined side forming tool descends to a predetermined distance) while the inclined side forming tool 90 rotates at a high speed, and the ascending is then performed. Accordingly, the hole 95a (cavity) is formed in the ceramic 95 to have the inclined side shown in FIG. 9B. Since the shape of the cutting part 94 of the inclined side forming tool 90 is conical, the hole 95a that is formed in the ceramic 95 has the corresponding shape to the cutting part. The hole 95a corresponds to the cavity of the upper ceramic substrate of FIG. 3.

[109] In connection with this, in order to form the hole 95a shown in FIG. 9B, it is required that a length (a) of the cutting part 94 (see FIG. 9A) is larger than a depth (b) of the hole 95a (see FIG. 9B). Subsequently, a reflection plate is provided on the inclined side of the hole 95a. In order to desirably emit light frontward that is emitted from the LED device and reflects from the reflection plate, the inclination angle of the tapering cutting part 94 is set to 10° to 45°. Accordingly, the inclination angle of the hole 95a that is formed in the ceramic 95 is set to 10° to 45°. Needless to say, the inclination angle of the inclined side of the hole 95a that is formed in the ceramic 95 may be set to 1° to 89° in some cases.

[110] In FIG. 9, the cutting blades 96 are distorted. However, the cutting blades may be straight. In the following description, the straight cutting blades may be used.

[I l l] In the description of FIGS. 9 and 10, the cavity shown in FIG. 3 may be precisely formed using the inclined side forming tool 90. Particularly, the problems that occur in FIGS. 3 to 5 may be avoided.

[112] In the following description that is given with reference to the other drawings, the rotational processing part 91 and the tightening part 93 are disclosed. The disclosed rotational processing part and the tightening part correspond to the rotational processing part 91 and the tightening part 93 shown in FIG. 10.

[113] FIG. 11 illustrates the formation of the cavity of the electronic part package according to the second embodiment of the present invention. [114] An inclined side forming tool 100 of FIG. 11 is different from the above-mentioned inclined side forming tool of FIG. 9 in view of the shape of the cutting part. That is, a cutting part 104 of the inclined side forming tool 100 of FIG. 11 is tapered at a lower portion and has the round tip. The cutting part 104 is formed at a lower portion of the cylindrical trunk part 102. A plurality of distorted cutting blades 106 are densely formed on a surface of the cutting part 104 at predetermined intervals. The other constitutions are the same as those of the above-mentioned inclined side forming tool of FIG. 9.

[115] The above-mentioned inclined side forming tool 100 is applied to the ceramic processing device (not shown). A description will be given of a method of forming the cavity in the ceramic using the inclined side forming tool 100. It is considered that the ceramic processing device (not shown) is operated by the automation program.

[116] First, the upper portion of the trunk part 102 of the inclined side forming tool 100 is inserted into the groove of the rotational processing part 91 of the ceramic processing device. Next, the rotational processing part 91 and the trunk part 102 are firmly combined with each other by using the tightening part 93.

[117] Subsequently, if the ceramic processing device is turned on by the worker, the ceramic processing device is operated according to the automation program to form the hole in the ceramic. That is, the rotational processing part 91 which is combined with the inclined side forming tool 100 moves upward and downward with respect to the ceramic that is disposed under the inclined side forming tool while rotating. A hole 105a is formed in the ceramic 105 (see FIG. 1 IB) by a single reciprocation of descending and ascending. In other words, the inclined side forming tool 100 that protrudes downward from the rotational processing part 91 vertically descends while rotating in conjunction with the rotational processing part 91 that rotates at a high speed. If the descending is performed to some degree (that is, the inclined side forming tool descends to a predetermined distance), the cutting part 104 of the inclined side forming tool 100 comes into contact with the ceramic 105. At this time, the descending is slightly performed (that is, the inclined side forming tool descends to a predetermined distance) while the inclined side forming tool 100 rotates at a high speed, and the ascending is then performed. Accordingly, the hole 105a (cavity) is formed in the ceramic 105 to have the inclined side shown in FIG. 1 IB. Since the cutting part 104 of the inclined side forming tool 100 is tapered at the lower end thereof and has the round tip, the hole 105a that is formed in the ceramic 105 has the corresponding shape to the cutting part.

[118] In order to form the hole 105a shown in FIG. 1 IB, it is required that a length (a) of the cutting part 104 (see FIG. 1 IA) is larger than a depth (b) of the hole 105a (see FIG. 1 IB). Since the inclined side of the hole 105a is formed to be concave, a pre- determined directional angle may be obtained with respect to light that reflects from the reflection plate which is to be subsequently provided. Accordingly, the desired direction of light may be ensured.

[119] FIG. 12 illustrates the formation of the cavity of the electronic part package according to the third embodiment of the present invention.

[120] An inclined side forming tool 110 of FIG. 12 is different from the above-mentioned inclined side forming tools of FIGS. 9 and 11 in view of the shape of the cutting part. That is, a cutting part 114 of the inclined side forming tool 110 of FIG. 12 is formed at a lower portion of a cylindrical trunk part 112. The cutting part 114 is formed to have a breast-like shape. A plurality of distorted cutting blades 116 are densely formed on a surface of the cutting part 114 at predetermined intervals. The other constitutions are the same as those of the above-mentioned inclined side forming tools of FIGS. 9 to 11.

[121] The above-mentioned inclined side forming tool 110 is applied to the ceramic processing device (not shown). A description will be given of a method of forming the cavity in the ceramic using the inclined side forming tool 110. It is considered that the ceramic processing device is operated by the automation program.

[122] First, the upper portion of the trunk part 112 of the inclined side forming tool 110 is inserted into the groove of the rotational processing part 91 of the ceramic processing device. Next, the rotational processing part 91 and the trunk part 112 are firmly combined with each other by using the tightening part 93.

[123] Subsequently, if the ceramic processing device is turned on by the worker, the ceramic processing device is operated according to the automation program to form the hole in the ceramic. That is, the rotational processing part 91 which is combined with the inclined side forming tool 110 moves upward and downward with respect to the ceramic that is disposed under the inclined side forming tool while rotating. A hole 115a is formed in the ceramic 115 (see FIG. 12B) by a single reciprocation of descending and ascending. In other words, the inclined side forming tool 110 that protrudes downward from the rotational processing part 91 vertically descends while rotating in conjunction with the rotational processing part 91 that rotates at a high speed. If the descending is performed to some degree (that is, the inclined side forming tool descends to a predetermined distance), the cutting part 114 of the inclined side forming tool 110 comes into contact with the ceramic 115. At this time, the descending is slightly performed (that is, the inclined side forming tool descends to a predetermined distance) while the inclined side forming tool 110 rotates at a high speed, and the ascending is then performed. Accordingly, the hole 115a (cavity) is formed in the ceramic 115 to have the inclined side shown in FIG. 12B. A portion of the lateral surface of the hole 115a which ranges from the uppermost portion of the hole to a predetermined point that is downward spaced apart from the uppermost portion is formed to be convex, and another portion of the lateral surface of the hole 115a which ranges from the lowermost portion of the convex portion to the lowermost portion of the hole 115a is formed to be concave. The hole 115a corresponds to the cavities of the upper ceramic substrates of FIGS. 6 and 8.

[124] In order to form the hole 115a shown in FIG. 12B, it is required that a length (a) of the cutting part 114 (see FIG. 12A) is larger than a depth (b) of the hole 115a (see FIG. 12B). Since the inclined side of the hole 115a has both the concave portion and the convex portion, the reflection plate which is to be provided on the inclined side of the hole 115a has the convex portion and the concave portion.

[125] FIG. 13 illustrates the formation of the cavity of the electronic part package according to the fourth embodiment of the present invention.

[126] An inclined side forming tool 120 of FIG. 13 is different from the above-mentioned inclined side forming tools of FIGS. 9 to 12 in view of the shape of the cutting part. That is, a cutting part 124 of the inclined side forming tool 120 of FIG. 13 is tapered at a lower portion and has the round tip. A protrusion 128 is formed at the center of the lower portion of the cutting part 124. The cutting part 124 is formed at a lower portion of the cylindrical trunk part 122. A plurality of distorted cutting blades 126 are densely formed on a surface of the cutting part 124 at predetermined intervals. The other constitutions are the same as those of the above-mentioned inclined side forming tools of FIGS. 9 to 12.

[127] The above-mentioned inclined side forming tool 120 is applied to the ceramic processing device (not shown). A description will be given of a method of forming the cavity in the ceramic using the inclined side forming tool 120. It is considered that the ceramic processing device is operated by the automation program.

[128] First, the upper portion of the trunk part 122 is inserted into the groove of the rotational processing part 91 of the ceramic processing device. Next, the rotational processing part 91 and the trunk part 122 are firmly combined with each other by using the tightening part 93.

[129] Subsequently, if the ceramic processing device is turned on by the worker, the ceramic processing device is operated according to the automation program to form the hole in the ceramic. That is, the rotational processing part 91 which is combined with the inclined side forming tool 120 moves upward and downward with respect to the ceramic that is disposed under the inclined side forming tool while rotating. A hole 125a is formed in the ceramic 125 (see FIG. 13B) by a single reciprocation of descending and ascending. In other words, the inclined side forming tool 120 that protrudes downward from the rotational processing part 91 vertically descends while rotating in conjunction with the rotational processing part 91 that rotates at a high speed. If the descending is performed to some degree (that is, the inclined side forming tool descends to a predetermined distance), the cutting part 124 of the inclined side forming tool 120 comes into contact with the ceramic 125. At this time, the descending is slightly performed (that is, the inclined side forming tool descends to a predetermined distance) while the inclined side forming tool 120 rotates at a high speed, and the ascending is then performed. Accordingly, the hole 125a (cavity) is formed in the ceramic 125 to have the inclined side shown in FIG. 13B. The hole 125a corresponds to the cavity of the upper ceramic substrate of FIG. 7.

[130] In order to form the hole 125a shown in FIG. 13B, it is required that a length (a) of the cutting part 124 (see FIG. 13A) is larger than a depth (b) of the hole 125a (see FIG. 13B).

[131] The above-mentioned ceramics that have the holes (that is, the cavities) formed using the inclined side forming tools of FIGS. 9 to 13 correspond to the upper ceramic substrates of FIGS. 2, 6, 7, and 8. That is, in the case of when the above-mentioned ceramics that have the holes formed using the inclined side forming tools of FIGS. 9 to 13 are produced, it is required that attachment to the lower ceramic substrate is performed.

[132] Hereinafter, a description will be given of the case of when the upper and the lower ceramic substrates are not separately produced.

[133] FIG. 14 illustrates the formation of the cavity of the electronic part package according to the fifth embodiment of the present invention.

[134] An inclined side forming tool 130 of FIG. 14 is different from the above-mentioned inclined side forming tools of FIGS. 9 to 13 in view of the shape of the cutting part. That is, a cutting part 134 of the inclined side forming tool 130 of FIG. 14 is tapered at a lower portion. Teeth 138 are formed on a lower surface of the cutting part 134. The cutting part 134 is formed at a lower portion of the cylindrical trunk part 132. A plurality of distorted cutting blades 136 are densely formed on a surface of the cutting part 134 at predetermined intervals. The other constitutions are the same as those of the above-mentioned inclined side forming tools of FIGS. 9 to 13.

[135] The above-mentioned inclined side forming tool 130 is applied to the ceramic processing device (not shown). A description will be given of a method of forming the cavity in the ceramic (or the ceramic substrate) using the inclined side forming tool 130. It is considered that the ceramic processing device is operated by the automation program.

[136] First, the upper portion of the trunk part 132 is inserted into the groove of the rotational processing part 91 of the ceramic processing device. Next, the rotational processing part 91 and the trunk part 132 are firmly combined with each other by using the tightening part 93.

[137] Subsequently, if the ceramic processing device is turned on by the worker, the ceramic processing device is operated according to the automation program to form the hole in the ceramic. That is, the rotational processing part 91 which is combined with the inclined side forming tool 130 moves upward and downward with respect to the ceramic that is disposed under the inclined side forming tool while rotating. A hole 135a is formed in the ceramic 135 (see FIG. 14B) by a single reciprocation of descending and ascending. In other words, the inclined side forming tool 130 that protrudes downward from the rotational processing part 91 vertically descends while rotating in conjunction with the rotational processing part 91 that rotates at a high speed. If the descending is performed to some degree (that is, the inclined side forming tool descends to a predetermined distance), the cutting part 134 of the inclined side forming tool 130 comes into contact with the ceramic 135. At this time, the descending is slightly performed (that is, the inclined side forming tool descends to a predetermined distance) while the inclined side forming tool 130 rotates at a high speed, and the ascending is then performed. Accordingly, the hole 135a (cavity) is formed in the ceramic 135 to have the bottom side and the inclined side shown in FIG. 14B.

[138] In order to form the hole 135a shown in FIG. 14B, it is required that a length (a) of the cutting part 134 (see FIG. 14A) is almost the same as a depth (b) of the hole 135a (see FIG. 14B).

[139] As shown in FIGS. 9 and 10, the ceramic 135 that has the hole 135a formed using the inclined side forming tool 130 desirably emits light frontward. Further, since the bottom side of the hole 135a is additionally processed, light that is generated downward from the LED device is desirably emitted frontward.

[140] FIG. 15 illustrates the formation of the cavity of the electronic part package according to the sixth embodiment of the present invention.

[141] An inclined side forming tool 140 of FIG. 15 is different from the above-mentioned inclined side forming tools of FIGS. 9 to 14 in view of the shape of the cutting part. That is, a cutting part 144 of the inclined side forming tool 140 of FIG. 15 is tapered at a lower portion. Teeth 148a and 148b are formed on a lower surface of the cutting part 144. A flat portion 150 is formed between the teeth 148a and the teeth 148b. The cutting part 144 is formed at a lower portion of the cylindrical trunk part 142. A plurality of distorted cutting blades 146 are densely formed on a surface of the cutting part 144 at predetermined intervals. The other constitutions are the same as those of the above-mentioned inclined side forming tools of FIGS. 9 to 14.

[142] The above-mentioned inclined side forming tool 140 is applied to the ceramic processing device (not shown). A description will be given of a method of forming the cavity in the ceramic (or the ceramic substrate) using the inclined side forming tool 140. It is considered that the ceramic processing device is operated by the automation program. [143] First, the upper portion of the trunk part 142 is inserted into the groove of the rotational processing part 91 of the ceramic processing device. Next, the rotational processing part 91 and the trunk part 142 are firmly combined with each other by using the tightening part 93.

[144] Subsequently, if the ceramic processing device is turned on by the worker, the ceramic processing device is operated according to the automation program to form the hole in the ceramic. That is, the rotational processing part 91 which is combined with the inclined side forming tool 140 moves upward and downward with respect to the ceramic that is disposed under the inclined side forming tool while rotating. A hole 145a (see FIG. 15B) is formed in the ceramic 145 (see FIG. 15B) by a single reciprocation of descending and ascending. In other words, the inclined side forming tool 140 that protrudes downward from the rotational processing part 91 vertically descends while rotating in conjunction with the rotational processing part 91 that rotates at a high speed. If the descending is performed to some degree (that is, the inclined side forming tool descends to a predetermined distance), the cutting part 144 of the inclined side forming tool 140 comes into contact with the ceramic 145. At this time, the descending is slightly performed (that is, the inclined side forming tool descends to a predetermined distance) while the inclined side forming tool 140 rotates at a high speed, and the ascending is then performed. Accordingly, the hole 145a (cavity) is formed in the ceramic 145 to have the bottom side and the inclined side shown in FIG. 15B.

[145] In order to form the hole 145a shown in FIG. 15B, it is required that a length (a) of the cutting part 144 (see FIG. 15A) is almost the same as a depth (b) of the hole 145a (see FIG. 15B).

[146] As shown in FIGS. 9 and 10, the ceramic 145 that has the hole 145a formed using the inclined side forming tool 140 desirably emits light frontward. Further, since the bottom side of the hole 145a is additionally processed, light that is generated downward from the LED device is desirably emitted frontward. Furthermore, since the LED device is mounted on the flat portion which is formed on the bottom side of the hole 145a, it is very easy to mount the LED device as compared to FIG. 14.

[147] In FIGS. 9 to 15, the inclined side forming tool on which a plurality of green sheets

(ceramic sheets) are layered is used. The inclined side forming tool may be used after the ceramic is sintered.

[148] That is, a metal layer 168 is applied on the ceramic 165 in which the inclined hole is formed as shown in FIG. 16A so as to form a power line and to ensure desirable reflection efficiency. Metal, such as Ag or AgPd, is shaped to form fine powder, mixed with a binder and a solvent to form a paste, and subjected to a printing process, a spraying process, or a sputtering process to form the metal layer 168. An Ag or an AgPd layer (that is, the metal layer 168) is formed in the hole of the ceramic 165 due to the interdiffusion between metal powders during the sintering of the ceramic 165 in an oxidation atmosphere at 800⁰C to 1000⁰C. An oxidized film that is formed of AgO is formed on the surface of the hole. If the Ag oxide film generated during the oxidation is removed, luster efficiency may be increased during the plating, and reflection efficiency of light is increased by 2% to 4% as compared to the case of before the oxide film is formed. Thus, light efficiency of the LED package is increased.

[149] Next, the metal layer 168 is processed using the inclined side forming tool 160 shown in FIG. 16B. Thereby, as shown in FIG. 16C, fine prominences and depressions are formed on the metal layer 168, or the metal layer 168 is flattened (that is, the metal layer is ground to be flat like a mirror). Therefore, surface roughness of the metal layer 168 can be controlled to ensure optimum efficiency. The surface roughness of the metal layer 168 is designed depending on the inclination angle, the shape of the inclined side, and the size of the LED device of the LED package. Typically, the surface roughness is designed to be 1 to 200 μm.

[150] Meanwhile, the inclined side forming tool 160 of FIG. 16B is almost similar to the inclined side forming tool of FIG. 14 or 15. However, they are different from each other in view of the shape of the cutting part. In FIG. 16B, reference numeral 162 denotes a trunk part. Reference numeral 164 denotes a cutting part. Reference numeral 166 denotes a cutting blade. Distortion of the cutting blade 166 of the inclined side forming tool 160 of FIG. 16 is more significant as compared to the inclined side forming tools of FIGS. 14 and 15.

[151] In other words, in FIG. 16, the metal layer 168 is applied on the inclined side of the hole 168a (also referred to as cavity) of the ceramic 165, and then, the metal layer 168 is processed using the inclined side forming tool 160. Alternatively, after the hole 168a (the cavity having the inclined side on which fine prominences and depressions are formed) is formed in the ceramic 165 using the inclined side forming tool 160, metal (for example, Ag, Al, or Au) may be applied on the inclined side of the hole 168a by sputtering.

[152] The present invention has been described in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Claims

[ 1 ] An electronic part package comprising: a lower ceramic substrate on which a mounting region of a light emitting device is formed; and an upper ceramic substrate which is disposed on the lower ceramic substrate and has a cavity formed in a region corresponding to the mounting region of the light emitting device, wherein the cavity has an inclined side tapered inward and the inclined side is roundly concave and convex.

[2] The electronic part package as set forth in claim 1, wherein a reflection plate is formed along the inclined side.

[3] The electronic part package as set forth in claim 2, wherein the inclined side is roundly convex in a range from an uppermost portion thereof to a lower point that is apart from the uppermost portion by a predetermined distance, and is roundly concave in a range from a lowermost portion of the convexed portion to a lowermost portion thereof.

[4] The electronic part package as set forth in claim 2, wherein the inclined side is roundly concave in a range from an uppermost portion thereof to a lower point that is apart from the uppermost portion by a predetermined distance, and is roundly convex in a range from a lowermost portion of the concaved pertion to a lowermost portion thereof.

[5] The electronic part package as set forth in claim 2, wherein the reflection plate is connected to a second pattern electrode which is formed on an upper side of the lower ceramic substrate to be spaced apart from a first pattern electrode formed in the mounting region of the light emitting device.

[6] The electronic part package as set forth in claim 1, wherein a cavity is formed in a lower side of the lower ceramic substrate.

[7] The electronic part package as set forth in claim 6, wherein a thermal via body is interposed between the cavity formed in the lower side of the lower ceramic substrate and a pattern electrode formed in the mounting region of the light emitting device.

[8] The electronic part package as set forth in claim 7, wherein a first pattern electrode that is electrically connected to at least one of the pattern electrodes formed on an upper side of the lower ceramic substrate, a second pattern electrode that is formed in the mounting region of the light emitting device and is electrically connected to the pattern electrode covering an upper side of the thermal via body, and a metal member that covers an internal lateral surface of the cavity of the lower ceramic substrate, is connected to a lower side of the thermal via body, and is spaced apart from the first and the second pattern electrodes are formed on the lower side of the lower ceramic substrate. [9] The electronic part package as set forth in claim 8, wherein a thermal conductive medium fills the cavity formed in the lower side of the lower ceramic substrate. [10] A method of forming a cavity in a ceramic substrate of an electronic part package, the method comprising: a first step of removably providing a tool that includes a cutting part having a cutting blade formed on an external surface thereof in a rotational processing part of a ceramic processing device; and a second step of shifting the tool toward the ceramic substrate by a predetermined distance while the tool rotates along with the rotational processing part and returning the tool to an original position of the tool to form a cavity having an inclined side in the ceramic substrate. [11] The method as set forth in claim 10, wherein the cutting part is longitudinally tapered toward a longitudinal end thereof. [12] The method as set forth in claim 10, wherein the cutting part longitudinally tapers toward a longitudinal end thereof to have a round longitudinal end. [13] The method as set forth in claim 10, wherein the cutting part longitudinally tapers toward a longitudinal end thereof to have a round longitudinal end and protrusion formed on the longitudinal end. [14] The method as set forth in claim 10, wherein the cutting part longitudinally tapers toward a longitudinal end thereof to have teeth on an edge of the longitudinal end thereof. [15] The method as set forth in claim 14, wherein a flat portion is formed at the center of the edge of the longitudinal end. [16] The method as set forth in claim 10, wherein a length of the cutting part is greater than or identical to a depth of the cavity formed in the ceramic substrate. [17] The method as set forth in claim 10, wherein the ceramic substrate is formed by layering a plurality of green sheets.