KR20080029571A - Light emitting diode - Google Patents

Abstract

A light emitting diode is provided to prevent a substrate from being damaged caused by the generation of step when a molding part is formed in a transfer mold scheme and the high pressure is applied. A light emitting diode includes a substrate(100), a light emitting chip(120), first and second lead patterns(104) and a molding unit. A through-hole(106) is formed on the substrate. The light emitting chip is adapted on a portion of the substrate. The first and second lead patterns are formed in one side and another side of the substrate with a distance therebetween, to apply external power source to the light emitting chip. The molding unit is employed to envelop the light emitting chip and fill the through-hole. The trough-hole is formed in at least a portion of the first lead pattern or second lead pattern or between the first and second patterns.

Description

Light Emitting Diodes {LIGHT EMITTING DIODE}

1 is a perspective view of a light emitting diode according to a first embodiment of the present invention;

FIG. 2 is a sectional view taken on line A-A in FIG. 1; FIG.

3 to 5 are perspective views illustrating a manufacturing process of a light emitting diode according to a first embodiment of the present invention.

6 is a perspective view of a light emitting diode according to a second embodiment of the present invention;

FIG. 7 is a sectional view taken on line B-B in FIG. 6; FIG.

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

100: substrate 104: lead pattern

106: through hole 120: light emitting chip

140: wiring 160: molding part

162: heat dissipation mold 164: heat dissipation mold plate

The present invention relates to a light emitting diode, and more particularly, to a light emitting diode having a structure capable of preventing the formation of steps in the lower surface of the substrate.

A light emitting diode (LED) refers to a device that generates a small number of carriers (electrons or holes) injected using a P-N junction structure of a compound semiconductor, and emits predetermined light by recombination thereof. The light emitting device using the light emitting diode as described above has a small power consumption and a lifetime of several to several tens of times compared to a conventional light bulb or a fluorescent lamp, and is superior in terms of reducing power consumption and durability. Such a light emitting diode typically includes a light emitting chip that is a compound semiconductor that emits light, a substrate on which the light emitting chip is mounted, and an external power supply member for applying external power is formed, and a molding for encapsulating and protecting the light emitting chip. It consists of wealth. In this case, a method of forming the molding part may include a casting mold method, a transfer molding method, and the like.

Among the light emitting diodes according to the related art, the light emitting diode forming the molding part by the transfer molding method is injected with an epoxy molding compound (EMC) using a mold press, encapsulating the light emitting chip with sufficient pressure and heat, and fixing the wiring. The molding part was formed.

However, in the light emitting diode according to the related art, a step is formed on the lower surface of the substrate due to the thickness of the external power supply member such as a lead pattern formed on the substrate, for example, the thickness of the lead pattern. When a high pressure is applied when the molding part is formed in the transfer molding method by the step as described above, a problem occurs in that the substrate is damaged by the step.

An object of the present invention is to solve the problems of the prior art described above, and to provide a light emitting diode capable of preventing damage to the substrate during transfer molding.

In order to achieve the above object, the present invention provides a substrate having a through hole, a light emitting chip mounted on a substrate other than the region where the through hole is formed, and an external power source applied to the light emitting chip to be spaced apart from each other, It provides a light emitting diode comprising a first and second lead pattern formed on the other side, and a molding part for sealing the light emitting chip and filling the through hole.

In this case, the through hole may be formed between at least a partial region of the first lead pattern or the second lead pattern or between the first and second lead patterns.

The molding part may include a lens part for encapsulating the light emitting chip, a heat dissipation mold filled in the through hole, and a heat dissipation mold plate formed between the first and second lead patterns of the lower surface of the substrate. In this case, the molding part may be formed by a transfer mold method.

In addition, the first and second lead patterns may include a heat sink.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Like reference numerals in the drawings refer to like elements.

1 is a perspective view of a light emitting diode according to a first exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line A-A of FIG.

As shown in FIGS. 1 and 2, the light emitting diode according to the first embodiment of the present invention includes a substrate 100 having a through hole 106, a heat sink 107 formed on a lower surface of the substrate 100, and First and second lead patterns 104a and 104b formed on upper and lower surfaces of the substrate 100, a light emitting chip 120 mounted on the first lead pattern 104a, and the light emitting chip. And a wiring 140 for electrically connecting the 120 and the second lead pattern 104b and a molding part 160 for encapsulating the light emitting chip 120 and the wiring 140.

The substrate 100 is to form a structure for mounting the light emitting chip 120 and applying an external power source, on both sides of the base plate, such as a double-side printed circuit board (DS PCB) The substrate on which the lead pattern is formed can be used.

The substrate 100 according to the present exemplary embodiment includes a base plate 102 and first and second lead patterns 104a and 104b formed to cover one side and the other side of the base plate 102. In addition, the through hole 106 vertically penetrates the substrate 100 to withstand the high pressure applied when the molding unit 160 is formed in the transfer mold method. In this case, EMC, which is a material used to form the molding part 160, is filled in the through hole 106 to form a heat dissipation mold 162, and the lower surface of the substrate 100 through the through hole 106. Is filled between the first and second lead patterns 104a and 104b to form the heat dissipation mold plate 164.

That is, a material forming the molding part 160 is formed on the bottom surface of the base plate 102 through the through hole 106 to compensate for the step formed by the first and second lead patterns 104a and 104b. The heat dissipation mold plate 164 is formed between the first and second lead patterns 104a and 104b formed at one side and the other side of the substrate. In this case, the heat dissipation molding plate 164 and the first and second lead patterns 104a and 104b have the same thickness, and therefore, the lower surface of the substrate 100 according to the present embodiment is formed flat.

In the light emitting diode according to the present embodiment, as described above, the step of the lower surface of the substrate 100 is removed, so that the pressure applied during the transfer mold process is evenly applied to the entire area of the lower surface of the substrate 100, thereby causing the substrate 100 to be reduced. ) Can be damaged.

In addition, in the light emitting diode according to the present exemplary embodiment, the heat dissipation molding plate 164 is formed by the thicknesses of the first and second lead patterns 104a and 104b and the heat dissipation plate 107 so that the bottom surface of the substrate 100 is flat. Therefore, even when the thick heat sink 107 is mounted on the substrate, the thickness of the heat dissipation mold plate 164 is also increased by the thickness thereof, so that the lower surface of the substrate 100 is flattened, thus enabling use of a thick heat sink. In addition, the heat generated from the light emitting diode can be discharged to the outside faster, thereby making it possible to manufacture a reliable light emitting diode less likely to be damaged by heat.

Meanwhile, the first and second lead patterns 104a and 104b are formed on the surfaces of the copper (Cu) layers 105d and 105a and the copper (Cu) layers 105d and 105a and have excellent electrical conductivity. Au) or silver (Ag) layers 105c and 105f, and nickel (Ni) layers 105b and 105e which are buffer layers for forming the gold (Au) or silver (Ag) layers. In this case, the copper (Cu) layer (105d, 105a) is formed on the front surface of the base plate 102, the lower surface of the copper (Cu) layer (105d, 105a) formed on the lower surface of the base plate 102 The pre-preg layer 101 for attaching the heat sink 107 by thermocompression is formed thereon. In addition, a heat dissipation plate 107 is formed on a lower surface of the pre-preg layer 101, and surrounds the copper (Cu) layers 105d and 105a and the heat dissipation plate 107 formed of the copper (Cu). Gold (Au) layers or silver (Ag) layers 105c and 105f are formed. In this case, the copper (Cu) layer 105d, the gold (Au) layer or silver (Ag) layer (105c, 105f) can be formed on the copper (Cu) layer (105d, 105a) and the heat sink (107) Nickel (Ni) layers 105b and 105e may be formed between the 105a) and the heat sink 107 and the gold (Au) layer or the silver (Ag) layer 105c and 105f.

The heat sink 107 is for quickly discharging heat generated during the operation of the light emitting chip 120 to the outside, and may be formed of a metal material having excellent thermal conductivity such as copper (Cu). The heat sink 107 may be formed on the bottom surface of the base plate 102.

In the present embodiment, when forming the through hole 106, a partial region of the first lead pattern 104a is overlapped. That is, the through hole 106 is a base plate 102 between at least a portion of the first lead pattern 104a and the first and second lead patterns 104a and 104b in which the first lead pattern 104a is not formed. Is formed. Therefore, heat generated in the light emitting chip 120 is transferred to the heat dissipation mold 162 formed in the through hole 106 and the heat dissipation mold plate 164 connected to the heat dissipation mold 162. However, the present invention is not limited thereto, and the through hole 106 may include at least a portion of the second lead pattern 104b and the first and second lead patterns 104a and 104b in which the second lead pattern 104b is not formed. It may be formed in the base plate 102 in between. However, it is preferable to improve the heat dissipation performance by forming the through hole 106 in a portion of the first lead pattern 104a that receives heat generated during the operation of the light emitting chip 120 directly. In addition, the through hole 106 may be enlarged in size or the number of the through holes 106 may be increased so that at least partial regions of the first and second lead patterns 104a and 104b and the first and second lead patterns 104a are formed. It may be formed on the base plate 102 between the 104b.

As described above, in the light emitting diode according to the present embodiment, heat generated during the operation of the light emitting chip 120 is transferred to the heat dissipation mold plate 164 through the heat dissipation mold 162 connected to the lens unit 161. The heat generated in 120 may be more quickly discharged to the outside. In addition, since the lens unit 161, the heat dissipation mold 162, and the heat dissipation mold plate 164 are integrally formed of the same material, heat is transferred more quickly because there is no heat resistance phenomenon occurring at the interface of different materials.

In addition, the lens unit 161 is connected to the heat dissipation mold plate 164 and the heat dissipation mold 162 by forming the through hole 106 as described above. Therefore, since the lens unit 161 is supported by the heat dissipation molding plate 164, the adhesion of the lens unit 161 becomes more excellent.

The light emitting chip 120 uses a phenomenon of emitting light by recombination of minority carriers (electrons or holes) as a compound semiconductor stacked structure having a p-n junction structure. The light emitting chip 120 may include first and second semiconductor layers (not shown) and active layers (not shown) formed between the first and second semiconductor layers. In this embodiment, the first semiconductor layer is a P-type semiconductor layer, and the second semiconductor layer is an N-type semiconductor layer. In addition, a P-type electrode (not shown) is formed on an upper surface of the light emitting chip 120, that is, on one surface of the P-type semiconductor layer, and an N-type electrode (on the lower surface of the light emitting chip 120, that is, on one surface of the N-type semiconductor layer). Not shown) is formed. In this case, the N-type electrode may be in contact with the first lead pattern 104a, and the P-type electrode may be electrically connected to the second lead pattern 104b by the wiring 140. However, the present invention is not limited thereto, and the light emitting chip 120 according to the present invention may use a horizontal light emitting chip in addition to the vertical light emitting chip as described above, and may use various types of light emitting chips emitting visible or ultraviolet light. .

Meanwhile, the light emitting device according to the present invention may use the wiring 140 to electrically connect the light emitting chip 120 and the lead pattern 104.

The wiring 140 is for electrically connecting the light emitting chip 120 and the second lead pattern 104b. The wiring 140 is formed of gold (Au) or silver (Ag) through a process such as a wire bonding process. Or it may be formed of a metal having excellent ductility and electrical conductivity, such as aluminum (Al). Meanwhile, when the light emitting chip 120 is horizontal, two wires may be used to electrically connect the first and second lead patterns 104a and 104b and the horizontal light emitting chip.

The molding part 160 encapsulates the light emitting chip 120, fixes the wiring 140 connected to the light emitting chip 120, and removes a step of the lower surface of the substrate 100. ) Is formed by a transfer mold method. In addition, the molding part 160 is formed in a specific shape to encapsulate the light emitting chip 120 and to fix the wiring 140 as well as to serve as a lens for collecting light emitted from the light emitting chip 120. It may be. Since the molding part 160 should serve as a lens part for transmitting the light emitted from the light emitting chip 120 to the outside, it is usually formed of a transparent resin. That is, the molding part 160 includes a lens part 161 for encapsulating the light emitting chip 120, a heat dissipation mold 162 connected to the lens part and filled in the through hole 106, and the heat dissipation mold ( The heat dissipation mold plate 164 connected to the 162 and filled between the first and second lead patterns 104a and 104b is included.

In this case, the molding unit 160 may further include a diffusion agent (not shown) to uniformly emit light by diffusing light emitted from the light emitting chip 120 by scattering. As the diffusion agent, barium titanate, titanium oxide, aluminum oxide, silicon oxide, or the like may be used. In addition, the molding unit 160 may further include a phosphor (not shown). The phosphor absorbs a part of the light emitted from the light emitting chip 120 and emits light having a wavelength different from that of the absorbed light. The phosphor is composed of a host lattice and an active ion in which impurities are mixed at an appropriate position. The role of the active ions determines the emission color by determining the energy level involved in the emission process, the emission color is determined by the energy gap between the ground state and the excited state of the active ion in the crystal structure. Such a phosphor and a diffusing agent are preferably included in the lens unit 161.

Next, a manufacturing process of a light emitting diode according to a first embodiment of the present invention will be described with reference to the accompanying drawings.

2 and 3 to 5 are perspective views for explaining the manufacturing process of the light emitting diode according to the first embodiment of the present invention.

2 and 3, a light emitting diode according to a first exemplary embodiment of the present invention firstly includes first and second lead patterns 104a and 104b and a heat dissipation plate surrounding one side and the other side of the base plate 102. 107 is formed, and a through hole 106 penetrating a partial region of the first lead pattern 104a and the base plate 102 is formed.

After the pattern is formed on the base plate through a dry film (D / F) process, the base plate 102, the pre-preg layer 101, the copper (Cu) layers 105d and 105a, and the heat sink ( A lay-up process of stacking 107 is performed. In addition, the substrate 100 having the layup process completed as described above is supplied to a press, and the prepreg is melted and cured by pressing and heating to form copper (Cu) layers 105d and 105a and the heat sink 107. The base plate 102 is bonded. Drilling to form through-holes 106 and connection holes 108 in the substrate 100 to which the copper (Cu) layers 105d and 105a and the heat sink 107 and the base plate 102 are bonded as described above. Perform the process. In this case, the through hole 106 overlaps the base plate 102 between the partial region of the first lead pattern 104a and the first and second lead patterns 104a and 104b to be formed later. 108 is preferably formed at the interface for cutting the substrate 100 for separation into unit light emitting diodes. Subsequently, this is patterned to form first and second lead patterns 104a and 104b and the heat sink 107 spaced apart from each other.

After forming the through hole 106 and the connection hole 108 as described above, the conductive layers of the upper and lower surfaces of the substrate 100, that is, the first and second lead patterns 104a and 104b are electrically connected to each other. In order to perform the electroless copper plating process, the first plating is performed to plate the inner circumference of the connection hole 108. In this case, the inner circumference of the through hole 106 may also be plated in the same manner as the connection hole 108.

Subsequently, unnecessary burrs and through holes 106 and connection holes 108 generated in the copper layers 105d and 105a and the heat sink 107 when the through hole 106 and the connection hole 108 are processed. The process of removing foreign substances in the shell) is carried out.

Next, a metal to be plated using a substrate 100 on which copper (Cu) layers 105d and 105a and a heat sink 107 are formed in a solution containing nickel sulfate, ammonium chloride, boric acid solution or nickel chloride, namely, Nickel (Ni) is disposed as an anode and then a DC current is conducted. In addition, after the nickel (Ni) layers 105b and 105e are formed, gold (Au) or silver (Ag) is plated in the same manner to form gold (Au) layers or silver (Ag) layers 105c and 105f. do. As described above, the direct current is conducted so that the metal in the solution is reduced by an electrochemical reaction, thereby performing secondary plating to form a thin film of the metal on the substrate 100 of the cathode. By performing the second plating, a gold (Au) layer or a silver (Ag) layer may be electrically plated on the inner wall and the surface of the electroless copper plated connection hole 108 to form a stable circuit thickness. The lead patterns 104a and 104b have high conductivity.

After performing a process such as a washing process for removing contaminants on the surface of the substrate 100 manufactured as described above, a substrate 100 cutting process is performed to cut a region in which the connection hole 108 is formed. However, the present invention is not limited thereto, and the cutting of the substrate 100 may be performed after the last step of the LED manufacturing process, that is, the molding part 160 is formed.

Next, referring to FIG. 4, the light emitting chip 120 is mounted on the first lead pattern 104a and the light emitting chip 120 and the second lead pattern 104b are connected to the wiring 140.

The light emitting chip 120 may be manufactured separately using various growth and deposition methods, and the light emitting chip 120 is mounted on the first lead pattern 104a using the light emitting chip 120 mounting equipment. . In this case, the light emitting chip 120 may be mounted using an adhesive member (not shown) such as silver paste. In addition, after mounting the light emitting chip 120 as described above, a wire bonding process may be performed to connect the light emitting chip 120 and the second lead pattern 104b to the wiring 140. ), A metal having excellent ductility and electrical conductivity, such as gold (Au), silver (Ag), or aluminum (Al), may be used.

Subsequently, as shown in FIG. 5, the molding unit 160 may be formed to encapsulate and protect the light emitting chip 120 and the wiring 140 to complete the light emitting diode according to the present embodiment.

The molding part 160 may be formed by injecting EMC using a mold press (not shown) and applying sufficient pressure and heat. At this time, in the present embodiment, the EMC is filled in the through hole 106 formed in the substrate 100 to form a heat dissipation mold 162, and the first and second lead patterns 104a and 104b through the through hole 106. The heat dissipation mold plate 164 is formed therebetween.

As described above, the EMC is filled between the first and second lead patterns 104a and 104b so that a step is not formed on the lower surface of the substrate 100. The substrate 100 is formed by a high pressure (about 1 ton) applied during the transfer mold. ) Can be prevented from being broken.

Next, a light emitting diode according to a second exemplary embodiment of the present invention will be described with reference to the accompanying drawings. The description overlapping with the first embodiment described above will be omitted or briefly described.

6 is a perspective view of a light emitting diode according to a second exemplary embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along line B-B of FIG. 6.

As shown in FIGS. 6 and 7, the light emitting diode according to the second embodiment of the present invention has a substrate 100 having a through hole 106 formed therein, and a first substrate formed on upper and lower surfaces of the substrate 100. And electrically connecting the second lead patterns 103a and 103b, the light emitting chip 120 mounted on the first lead pattern 103a, and the light emitting chip 120 and the second lead pattern 103b. And a molding unit 160 for encapsulating the light emitting chip 120 and the wiring 140.

The substrate 100 is to form a structure for mounting the light emitting chip 120 and applying an external power source, the same as the first embodiment described above, a double-side printed circuit board (DS); Like the PCB), a substrate having lead patterns formed on both surfaces of the substrate may be used.

At this time, in the above-described first embodiment, a partial region of the first lead pattern 103a or the second lead pattern 103b and the first and second lead patterns 103a and 103b are not formed in the through hole 106. Although not formed in the base plate 102 between the first and second lead patterns 103a and 103b, in the present embodiment, the through hole 106 is formed in the first lead pattern 103a and the second lead pattern 103b. Form between. That is, the through hole 106 is formed in the base plate 102 on which the first and second lead patterns 103a and 103b are not formed.

In addition, the first and second lead patterns 103a and 103b of the light emitting diode according to the present embodiment may include copper (Cu) layers 101d and 101a formed on the surface of the base plate 102 and the copper (Cu) layer. Gold (Au) layer or silver (Ag) layer 101f, 101c formed on the surface of (101d, 101a) is included. In this case, the copper (Cu) layers 101d and 101a and gold (A) to form a gold (Au) layer or a silver (Ag) layer (101f, 101c) on the surfaces of the copper (Cu) layers 101d and 101a. Nickel (Ni) layers 101e and 101b may be formed between the Au layer or the silver (Ag) layers 101f and 101c. That is, the light emitting diode according to the present invention may be applied to a light emitting diode in which the heat sink 107 is not formed in the first and second lead patterns 103b and 103a, and the effects thereof are the same as in the above-described first embodiment. May appear.

Although described above with reference to the drawings and embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit of the invention described in the claims below. I can understand.

For example, in the present embodiment, the case where the light emitting chip is mounted on the lead pattern has been described as an example. However, the present invention is not limited thereto, and the present invention may be applied to the case where the light emitting chip is mounted on the base plate.

As described above, the present invention can provide a light emitting diode capable of preventing the breakage of the substrate due to the pressure by removing the step of the lower surface of the substrate so that the pressure applied during the transfer mold process is evenly applied to the entire area of the lower surface of the substrate. have.

In addition, it is easy to remove the step of the lower surface of the substrate can be used than the conventional heat sink, and the heat generated during the operation of the light emitting chip by the heat dissipation mold formed when the step of removing the heat sink and the lower surface of the substrate to the outside more quickly It can be discharged to minimize the damage of the light emitting diode due to heat can provide a reliable light emitting diode.

In addition, since the molding part, the heat dissipation mold, and the heat dissipation mold plate are integrally formed of the same material, there is no heat resistance phenomenon occurring at the interface of different materials so that heat generated from the light emitting chip can be discharged to the outside more quickly.

In addition, since the molding part is connected to the heat dissipation mold plate and the heat dissipation mold by the through hole formed in the substrate, and is supported by the heat dissipation mold plate, the adhesion of the molding part is more excellent.

Claims (5)

A substrate having a through hole formed therein; A light emitting chip mounted on a substrate other than the region where the through hole is formed; First and second lead patterns formed on one side and the other side of the substrate while being spaced apart from each other by applying external power to the light emitting chip; And a molding part encapsulating the light emitting chip and filling a through hole. The method according to claim 1, The through hole may be formed in at least a portion of the first lead pattern or the second lead pattern or between the first and second lead patterns. The method according to claim 1, The molding unit and the lens unit for encapsulating the light emitting chip; A heat dissipation mold filled in the through hole, And a heat dissipation mold plate formed between the first and second lead patterns of the lower surface of the substrate. The method according to claim 1, The molding unit is a light emitting diode, characterized in that formed in the transfer mold method. The method according to any one of claims 1 to 3, The first and second lead pattern is a light emitting diode, characterized in that it comprises a heat sink.

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