KR100701980B1 - Preparing method of led package and led package manufactured thereby - Google Patents

Abstract

A method for manufacturing LED package and an LED package manufactured thereby are provided to enhance a light condensing efficiency and to improve a heat radiating efficiency by using a reflective wall and a heat radiating path. First to third electrode patterns(122,123,124) are formed on a substrate(110). An Ag reflective wall is formed on the resultant structure by performing Ag plating on the third electrode pattern. An insulating solder layer(140) is formed on the substrate including the first and the second electrode patterns. A plurality of LED chips(150) are attached to the resultant structure. The first and the second electrode patterns are electrically connected with the plurality of LED chips by a wire bonding process.

Description

Method for manufacturing LED package and LED package manufactured therefrom {PREPARING METHOD OF LED PACKAGE AND LED PACKAGE MANUFACTURED THEREBY}

1 is a view of a lighting LED package according to the manufacturing method of the present invention, Figure 1a is a plan view, Figure 1b is a cross-sectional view taken along the cutting line A1-A1 '.

2 is a view of a LED package for a backlight according to the manufacturing method of the present invention, Figure 2a is a plan view, Figure 2b is a cross-sectional view for the cutting line A2-A2 ', Figure 2c is a cross-sectional view for the cutting line B1-B1'. to be.

3 is a partial cross-sectional perspective view of the LED package with a metal reflecting wall according to the present invention.

<Explanation of symbols for the main parts of the drawings>

110, 210: laminated ceramic substrate 111, 211: through hole

122, 222: first electrode 123, 223: second electrode

124: electrode for reflecting wall 130, 230: reflecting wall

140, 240: solder layer 150, 250: LED

160, 260: heat sink 171: copper (Cu) layer

172: nickel (Ni) layer 173: gold (Au) layer

180, 280: bonding wires 231, 261: adhesive layer

300: metal reflective wall 310: metal plate

311: nickel electroless plating layer 312: silver (Ag) plating layer

313: transparent polymer protective layer

The present invention relates to a method of manufacturing a light emitting diode (LED) package and an LED package manufactured therefrom, and more particularly, to a backlight or lighting LED package including an LED array in which a plurality of LEDs are arranged.

In general, the light emitting device has been used as a display device using simple light emission, but recently, the possibility of a light source having various wavelengths and energy has been studied. Among light emitting devices, LEDs are applied to a wide range of applications such as not only general display devices but also backlight devices of lighting devices and LCD displays. In particular, LED has the advantage of low heat generation and long life due to high energy efficiency while being able to drive at a relatively low voltage, and most of the currently used technologies have been developed to provide high brightness of white light, which was difficult to implement in the past. It is expected to replace the light source device.

Research is being conducted to arrange such LEDs in an array and use them as backlights for display devices that are difficult to emit light. In particular, cold cathode tubes (CCFLs) used in thin film transistor (TFT) LCDs, which are rapidly increasing in use, are being researched. It is expected to be a backlight source that can replace).

The LED emits light by applying a voltage between the p-electrode and the n-electrode. When the voltage is applied, holes and electrons are injected into the p-electrode and the n-electrode. To use the principle of emission.

The LED formed in the form of a chip may be directly applied on a substrate, and may be attached to various packages such as an epoxy molding and a can-type package. However, when the epoxy molding is formed, the light efficiency is lowered by the epoxy, it is difficult to obtain an even luminous effect, and the light spreads in all directions, so that the light cannot be condensed to the front. Difficult to place When used in a can-type package, the size of the package is large, which makes it difficult to form a compact source for forming a light source and increases the cost. Therefore, in order to form such a line light source, it is common to attach a chip directly on a substrate. In this case, since light scatters in all directions, interference occurs and light is not focused on the front surface, thereby greatly reducing efficiency. In addition, it is difficult to dissipate heat generated because the LED invented during bonding is directly bonded onto the substrate, thereby reducing the lifespan and changing characteristics.

An object of the present invention is to provide a method of manufacturing an LED package excellent in light condensing efficiency and heat dissipation efficiency while increasing the integration degree of the LED chip by solving the above problems.

It is another object of the present invention to provide an LED package manufactured by the above manufacturing method and suitable for use as a light source such as for illumination or backlight.

The present invention provides a method of manufacturing a LED package, surrounding the plurality of LED chip array bonded on the metal electrode pattern formed on the substrate, the light collection efficiency of light emitted from the LED by forming a closed curved reflection wall higher than the LED chip In addition, by providing a heat dissipation passage between the reflecting wall and the heat sink of the lower part of the substrate to effectively discharge the heat generated during the LED operation was able to achieve the above object.

The present invention relates to a method for manufacturing an LED package and an LED package manufactured by the same, and more particularly, after forming a first electrode and a second electrode pattern for electrically connecting a plurality of LED chips on the substrate, The LED package manufacturing method and the LED package manufactured by surrounding the plurality of LED chip array on the reflective wall electrode pattern, comprising the step of forming a closed curved reflective wall higher than the LED chip.

In addition, the LED package manufacturing method according to the present invention is provided with a metal heat sink in the lower portion of the substrate, and a heat dissipation passage for connecting the reflective wall and the heat sink in the substrate, the heat generated from the upper substrate through the reflective wall and the heat dissipation passage The present invention relates to a method of manufacturing an LED package having excellent heat dissipation effect because it is effectively delivered to a heat sink.

In addition, the present invention provides an LED package manufactured by the above manufacturing method, the LED package according to the present invention is not necessary to limit the use, but is suitable for use for a backlight unit or lighting.

Hereinafter, the present invention will be described in more detail.

At this time, if there is no other definition in the technical terms and scientific terms used, it has a meaning commonly understood by those of ordinary skill in the art.

In addition, repeated description of the same technical configuration and operation as in the prior art will be omitted.

The LED package manufacturing method according to the first aspect of the present invention comprises the following steps.

(a) forming an electrode pattern on the substrate to form first and second electrode patterns electrically connected to the plurality of LED chips and an electrode pattern for a reflective wall surrounding the plurality of LED chip arrays;

(b) a silver (Ag) reflective wall forming step of plating silver (Ag) on the reflective wall electrode pattern at high speed;

(c) forming an insulating solder layer on the substrate on which the first electrode and the second electrode pattern are formed and attaching a plurality of LED chips; And

(d) wire bonding a step of wire bonding the first electrode and the second electrode with the mounted LED chip.

In addition, the LED package manufacturing method according to the second aspect of the present invention comprises the following steps.

(a) forming an electrode pattern on the substrate to form a first electrode and a second electrode pattern for electrically connecting the plurality of LED chips;

(b) forming an insulating solder layer on the substrate on which the first and second electrode patterns are formed and attaching a plurality of LED chips; And

(c) a wire bonding step of wire bonding the first electrode and the second electrode with the mounted LED chip;

(d) attaching a closed curved resin reflective wall or metal reflective wall surrounding the plurality of wire bonded LED chips.

The reflective wall formed by the manufacturing method according to the first and second aspects is preferably formed higher than the height at which the LED of the LED bonding step is located.

In the LED package manufacturing method according to the present invention, a ceramic substrate, a PCB, and a metal PCB may be used as the substrate. However, when the ceramic substrate is used, thermal conductivity and flatness are superior to those of the conventional PCB substrate. The multilayer ceramic substrate may be a low temperature cofired ceramic (LTCC) or a high temperature cofired ceramic (HTCC) substrate. HTCC is a high-temperature calcined multilayer ceramic, which has high dielectric constant, inferior processing accuracy to LTCC, but low cost. LTCC is a low temperature calcined multilayer ceramic with low resistance, excellent machining accuracy, and low dielectric constant than HTCC. Since HTCC requires a firing temperature of about 1600 ° C or higher, high melting point W or Mo-based metals should be used, whereas LTCC has a firing temperature of 1000 ° C or lower, so it is inexpensive and low melting point like Ag or Cu. It has the advantage that the metal of conductivity can be used as the inner wiring material, and the line resistance is reduced by more than 70% than HTCC, and the LTCC process is basically based on MLC (Multi-Layer Ceramic) technology. Although similar to the HTCC process, the green sheet is sintered at the same time as the electrode. The thickness of the ceramic substrate is suitably in the range of 300 µm to 1500 µm.

In the multilayer ceramic substrate according to the present invention, multilayer ceramic substrates are electrically connected to each other by via holes. In addition, the multilayer ceramic substrate according to the present invention preferably includes a heat dissipation passage connected to the heat sink under the substrate by forming a plurality of through holes in the region where the reflective wall is formed. The size of the through hole may vary depending on the thickness of the substrate and the width of the reflective wall forming region, but preferably, the hole has a diameter of 100 μm to 500 μm. The heat dissipation passage is made before the simultaneous firing step in the manufacturing of the substrate, forming a plurality of through holes penetrating the substrate in a portion of the region where the upper reflective wall is formed, filling the conductive metal paste in the through holes; And a metal paste filled during the firing of the substrate is fired. The LED package according to the present invention has a heat dissipation passage connected to a reflective wall located on the upper substrate and a heat sink attached to the lower substrate, thereby effectively dissipating heat generated by the operation of the plurality of LEDs on the upper substrate. There are advantages to it. The metal paste to be filled is preferably a silver (Ag) paste in consideration of thermal conductivity and compatibility.

The forming of the electrode pattern may include forming a copper plating layer by electroless copper plating and electrolytic copper plating, forming a copper wiring by a photolithography process and an etching process on the multilayer ceramic substrate, nickel plating, And gold or silver plating steps sequentially. Electroless copper plating thickness is about 0.1-1 micrometer, and the thickness of the electroplated copper is about 1-10 micrometers. In the conventional case, the electrode was formed by a printing method using silver paste. However, since the electrode pattern gradually becomes fine according to the high integration of the semiconductor device, it is difficult to form the fine pattern by the conventional method and the adhesiveness with the substrate is also poor. After the copper plating layer is formed by electroless plating and copper plating, the photoresist pattern is formed on the copper plating layer by a photolithography process, the copper plating layer is etched by wet etching, and the resist pattern is removed to remove copper. An electrode pattern is formed. At this time, the copper electrode pattern is formed in the region where the reflective wall is formed. Subsequently, nickel plating and gold or silver plating are sequentially performed to form an electrode pattern made of copper-nickel-gold or copper-nickel-silver. Nickel plating thickness is about 2-4 micrometers, gold plating thickness advances so that it may become 0.5 micrometer or more, It is preferable to have a range of about 0.5-1.5 micrometers, and silver plating thickness advances so that it may be 1 micrometer or more, It is preferable to have a range of about 3 μm.

In the manufacturing method according to the first aspect, the electrode pattern is also formed in the reflecting wall and the heat sink forming region, thereby forming a reflecting wall by electroplating silver (Ag) on the metal wiring formed in the reflecting wall and the heat sink region. It is preferable to use a high speed plating method using a high speed electrolytic plating apparatus because it takes a very long time to form a reflective wall having a height of about 200 to 1000 μm by conventional electroplating. The high speed electrolytic plating method may be performed by the high speed silver plating apparatus disclosed in Korean Patent Application No. 2006-0017325 filed by the present inventors.

After forming the electrode pattern, a solder layer for LED bonding is formed on the formed first electrode and the second electrode pattern. The solder layer uses an insulating material capable of structurally bonding LEDs, and an epoxy resin may be exemplified. After the solder layer is formed, the LED is disposed on the solder layer, and then the LED is bonded to the substrate on which the electrode wiring is formed.

According to the manufacturing method according to the second aspect of the present invention, a reflective wall is formed by attaching a resin reflective wall or a metal reflective wall. The resin for the reflective wall may be a resin composition prepared by mixing a fiber-like or flake-shaped inorganic compound that can reflect light to a thermoplastic resin, and the resin composition may be in the form of a closed curve surrounding the plurality of LED chip arrays. After injection and molding, the reflective wall can be formed by attaching to the reflective wall forming region. The resin reflecting wall or the metal reflecting wall has an inclination angle of 8 to 45 ° with respect to the substrate, and the inclination angle can be adjusted in the above range in consideration of the concentration of light. The metal reflective wall is a metal reflective wall forming step of forming a metal plate selected from Ni, Cu, or Al into a closed curve surrounding a plurality of LED chips, and silver (Ag), chromium (Cr), Or it is produced by a manufacturing method comprising an electroplating step of forming a mixed plating layer of silver and chromium. In the forming step, a metal plate having excellent thermal conductivity selected from Ni, Cu or Al is manufactured in the form of a reflective wall having a height of 300 μm to 2 mm by a mold method. In the case of using Cu or Al as the metal plate, it is preferable to further include forming a Ni electroless plating layer before the silver (Ag) electroplating step, since the adhesion of the electrolytic plating layer is significantly improved by the nickel electroless plating layer. to be. In the electrolytic plating step, the reflection efficiency is increased by forming silver (Ag), chromium (Cr), or a mixed plating layer of silver and chromium. As for the thickness of an electrolytic plating layer, 5-10 micrometers is preferable. When plating below the thickness, the effect of improving the luminance may be insignificant due to the increase in reflectivity. In the case of plating above the thickness, the reflectivity may not be improved any more, which may be economically disadvantageous. The method may further include forming a transparent polymer resin layer on the electroplating layer to protect the reflective wall from contamination of metal, dust, fingerprints, and the like. When the transparent polymer resin layer is formed by coating a coating solution containing 10 to 30% by weight of the modified silicone resin, the decrease in reflectance hardly occurs, and the heat resistance and antifouling performance were excellent. The coating may be made by a conventional method such as spray coating or dip coating, and drying after the coating step is preferably performed at 200 to 300 ° C. for 10 to 30 minutes.

The resin reflecting wall, the metal reflecting wall or the heat sink is attached to the substrate by an adhesive layer, the adhesive layer may be epoxy resin, silicone resin and the like, but polymethyl siloxane (Polymethyl siloxane; PDMS) 90 ~ 99% by weight and boron nitrite In the case of using a silicone resin composition in which a platinum (Pt) catalyst is contained in an amount of 0.05 to 0.5 parts by weight based on 100 parts by weight of the mixture, it is not only excellent in adhesiveness, It was more preferable because it was excellent in thermal conductivity.

The metal heat sink attached to the lower portion of the ceramic substrate is required to improve heat and reliability of the package by dissipating heat generated by the LED operation on the substrate, and copper or silver materials may be used, but the present invention is not limited thereto. . In addition, the metal heat dissipation plate is more preferable to increase the surface area by forming irregularities on the heat dissipation plate in order to more effectively release heat. In consideration of the heat dissipation effect and economic efficiency, the thickness of the heat sink is preferably in the range of 200 to 1000 μm.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to ensure that the spirit of the invention to those skilled in the art will fully convey. Accordingly, the invention is not limited to the embodiments described below and may be embodied in other forms. In the drawings, lengths, thicknesses, and the like of layers and regions may be exaggerated for convenience. Like numbers refer to like elements throughout.

Figure 1 shows an illumination LED package as an embodiment according to the invention Figure 1a shows a plan view of the illumination LED package, Figure 1b shows a cross-sectional view (A1-A1 '). Hereinafter, a manufacturing method of the LED package according to the present invention will be described in more detail with reference to FIG. 1. Referring to FIG. 1B, a plurality of through holes 111 are formed in the multilayer ceramic substrate 110. The multilayer ceramic substrate is a 900 μm thick LTCC substrate, 300 μm before firing of the substrate After forming a plurality of holes of the size, the silver (Ag) paste was filled in the holes and simultaneously fired when the substrate was fired. The first electrode 122 and the second electrode 123 are formed on the ceramic substrate, which includes a copper layer 171, a nickel layer 172, and a gold layer 173. The copper layer was formed by 0.5㎛ by the conventional electroless plating method and 4.5㎛ by the electroplating method, and then formed a resist pattern through a conventional photolithography process using a dry film resist and then etching the copper film Copper patterns were prepared. Nickel 3 μm and gold 0.7 μm were sequentially grown on the prepared copper pattern by electrolytic plating to form an electrode pattern made of a copper-nickel-gold layer. When forming the copper pattern, a reflective wall electrode 124 pattern was formed even in a region where a reflective wall was formed, and the high-speed silver plating apparatus disclosed in Korean Patent Application No. 2006-0017325 was applied to the reflective wall electrode pattern at a high speed of 600 μm. A silver (Ag) reflective wall 130 of height was formed. After the reflective wall forming process, the solder layer 140 is formed at a predetermined position where the LED is disposed. As a solder layer, the adhesive epoxy resin normally used was used. As shown in FIGS. 1A and 1B, the LEDs 150 are placed on the epoxy resin layer so that the six LEDs are arranged in a circular shape, and then compressed and dried to cure the epoxy resin. Subsequently, a wire bonding 180 process for electrically connecting the LED mounted on the substrate to the first electrode and the second electrode was performed. The wire bonding process was performed according to a conventional wire bonding method using gold (Au) wire. 500㎛ after wire bonding The Ag heat sink 160 having a thickness was attached to the lower portion of the substrate 110 by the adhesive layer 161. The adhesive layer was formed using a silicone resin adhesive. The heat sink attachment process may be performed after the step of plating the silver with the high speed silver plating apparatus to form the reflective wall.

2A to 2C show an LED package for an LCD backlight as another embodiment of the present invention. The detailed manufacturing method is the same as the manufacturing method of the LED package for illumination of FIG. 1, but the reflective wall 230 is formed using a resin reflective wall instead of silver (Ag) plating on the reflective wall electrode. The reflective wall resin was injected and molded at 600 μm in the shape of the reflective wall region of FIG. 2A using Otsuka Chemical's trade name TISMO POTICON NM114WA. The reflective wall 230 is attached to the laminated ceramic substrate 210 by the adhesive layer 231. Heat emitted from the LED is transferred to the heat sink 260 by the through hole 211 in the substrate formed under the reflective wall 230, and the heat sink is attached to the substrate by the adhesive layer 261. Referring to Figure 2a it can be seen that the LED package for the LCD backlight is manufactured in the form of a plurality of LEDs arranged in a straight line. Although FIG. 2A shows that 6 to 9 LEDs are arranged, the LEDs to be arranged are not limited thereto. In the case of a conventional LED package, a maximum of about 30 LEDs may be arranged in 7 inches. It can be arranged up to 48 in 7 inches has the advantage of high LED integration.

FIG. 2B is a cross-sectional view taken along the line A2-A2 'of FIG. 2A, and the reflective wall 230 is formed adjacent to the LED 250 to effectively collect the emitted light, and through the inside of the substrate 210. The heat generated by the LED operation through the 211 is effectively discharged to the heat sink (260). 2C is a cross-sectional view of B1-B1 ', in which a plurality of arrays of LEDs 250 are formed in a row, each LED is mounted on a solder layer 240 formed on a substrate on which a metal pattern is formed, and a first electrode. 222 and the second electrode 223 are electrically connected to each other by wire bonding 280.

In addition, a metal reflective wall may be attached instead of the resin reflective wall of FIG. As an example of a metal reflective wall, FIG. 3 shows an LED package in which a metal reflective wall is attached by an adhesive layer 231. Referring to the partial cross-sectional view of FIG. 3, the metal reflective wall 300 is formed by forming a metal reflective wall having a height of 1 mm using a Cu metal plate 310 as a mold, and then forming a Ni electroless plating layer 311 having a thickness of 2.5 μm. Afterwards, silver electroplating was performed to form an electrolytic plating layer 312 having a thickness of 6.5 μm, and then immersed in a transparent polymer coating liquid containing a modified silicone resin and dried to form a polymer protective layer 313 having a thickness of 1.5 μm. Adhered to the substrate.

The present invention relates to a method of manufacturing an LED package including a plurality of LED arrays and to an LED package manufactured therefrom. The LED package according to the method of the present invention has a high degree of LED integration to form a line light source for use in lighting and backlighting. It has a reflective wall surrounding the LED array made up of a plurality of LED chips, and effectively reflects the light emitted from the LED, so that the light condensing effect is excellent, and a heat dissipation path connecting the reflective wall and the heat sink under the substrate. It is provided inside the substrate has an advantage of excellent heat dissipation effect.

Claims (14)

(a) forming an electrode pattern on the substrate to form first and second electrode patterns electrically connected to the plurality of LED chips and an electrode pattern for a reflective wall surrounding the plurality of LED chip arrays; (b) a silver (Ag) reflective wall forming step of plating silver (Ag) on the reflective wall electrode pattern at high speed; (c) forming an insulating solder layer on the substrate on which the first electrode and the second electrode pattern are formed and attaching a plurality of LED chips; And (d) a wire bonding step of wire bonding the first electrode and the second electrode with the mounted LED chip; LED package manufacturing method comprising a. (a) forming an electrode pattern on the substrate to form a first electrode and a second electrode pattern for electrically connecting the plurality of LED chips; (b) forming an insulating solder layer on the substrate on which the first and second electrode patterns are formed and attaching a plurality of LED chips; And (c) a wire bonding step of wire bonding the first electrode and the second electrode with the mounted LED chip; (d) attaching a closed curved resin or metal reflective wall surrounding the plurality of wire bonded LED chips; LED package manufacturing method comprising a. The method of claim 2, The metal reflective wall is a metal reflective wall forming step of forming a metal plate selected from Ni, Cu or Al in a closed curve surrounding a plurality of LED chips; And An electroplating step of forming silver (Ag), chromium (Cr), or a mixed plating layer of silver and chromium on the surface of the formed metal reflective wall; LED package manufacturing method characterized in that it was manufactured by a manufacturing method comprising a. The method of claim 3, The metal reflection wall is a metal reflection wall forming step of forming a metal plate selected from Cu or Al into a closed curve surrounding a plurality of LED chips; A Ni electroless plating step of forming a Ni layer on the formed metal reflective wall surface; And An electroplating step of forming silver (Ag), chromium (Cr), or a mixed plating layer of silver and chromium on the Ni layer; LED package manufacturing method characterized in that it was manufactured by a manufacturing method comprising a. The method of claim 3, The method of claim 1, further comprising forming a transparent polymer protective layer after the electrolytic plating step. The method of claim 4, wherein The method of claim 1, further comprising forming a transparent polymer protective layer after the electrolytic plating step. The method of claim 5, The transparent polymer protective layer is formed by coating a coating liquid containing a modified silicone resin. The method according to any one of claims 1 to 7, wherein The substrate is a method of manufacturing an LED package, characterized in that the laminated ceramic substrate selected from LTCC or HTCC substrate. The method of claim 8, The multilayer ceramic substrate may be formed by forming a plurality of holes in a portion of a region where a reflective wall is formed, filling conductive metal paste in the holes, and firing the filled metal paste during firing of the substrate. LED package manufacturing method comprising the formed heat dissipation passage. The method of claim 8, The LED package manufacturing method further comprising the step of attaching a metal heat sink under the multilayer ceramic substrate. The method of claim 9, The resin reflecting wall, the metal reflecting wall, or the metal heat dissipating plate may include 0.05 to 0.5 parts by weight of a platinum catalyst in a mixture composed of 90 to 99% by weight of polymethylsiloxane and 1 to 10% by weight of boron nitride. LED package manufacturing method characterized in that the adhesive to the substrate by a silicone resin. The method of claim 8, The forming of the electrode pattern may include forming a copper plating layer by electroless copper plating and electrolytic copper plating, forming a copper wiring by a photolithography process and an etching process on the multilayer ceramic substrate, nickel plating, And a gold or silver plating step sequentially. delete delete

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