KR100801921B1 - Fabrication method of light emitting diode - Google Patents

Abstract

A method for manufacturing a light emitting diode is provided to obtain light with a uniform color by coating powders including phosphors having uniform density on a semiconductor layer. A substrate preparation process is performed to prepare a substrate(100). A semiconductor layer forming process is performed to form a semiconductor layer(210) on an upper surface of the substrate. A power preparation process is performed to prepare powders including phosphors. A phosphor layer forming process is performed to form a phosphor layer(240) by coating the powders including the phosphors on the semiconductor layer. The power preparation process includes a process for manufacturing the powders including the phosphors by mixing a powder resin with the phosphor powders.

Description

Light emitting diode manufacturing method {FABRICATION METHOD OF LIGHT EMITTING DIODE}

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

2 is a perspective view of a phosphor layer according to a first embodiment of the present invention;

3 to 6 are perspective views illustrating a manufacturing process of a light emitting diode according to a first embodiment of the present invention.

7 is a schematic cross-sectional view of a light emitting diode according to a second embodiment of the present invention.

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

100: substrate 210: semiconductor layer

210a: first semiconductor layer 210b: second semiconductor layer

210c: active layer 212: electrode

212a: first electrode 212b: second electrode

214: wire bonding pad 214a: first wire bonding pad

214b: second wire bonding pad 230: wiring

230a: first wiring 230b: second wiring

240: phosphor layer 241: phosphor-containing powder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to light emitting diodes, and more particularly, to light emitting diodes having a phosphor layer in which phosphors are uniformly distributed.

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. In order to use the light emitting diode as described above, the light emitting diode should emit visible light. As the light emitting diode for lighting, a light emitting diode emitting white light is usually used. In order to emit light wavelength of the white region, the light emitting diode implements white light by combining a light emitting chip emitting a specific range of light wavelengths and a phosphor that can excite the light emitted from the light emitting chip to a light wavelength in a desired range. . In this case, in order for the phosphor to excite the light emitted from the light emitting chip, a phosphor should be formed on the light emitting chip.

Conventionally, when the phosphor is formed on the light emitting chip, a mixture of the phosphor and the liquid resin is applied or molded on the light emitting chip. However, the light emitting diode according to the related art having the structure described above has a problem that the phosphor is not uniformly distributed in the liquid resin, so that light having a uniform color cannot be realized when the light emitted from the light emitting chip is excited by the phosphor. have. When a mixture of various phosphor powders are used, for example, when a white light emitting diode is manufactured using a mixture of red (R), green (G), and blue (B) phosphor powders having an appropriate blending ratio with an ultraviolet light emitting chip, Since each phosphor has a different specific gravity and particle size, the distribution of the phosphor is nonuniform and the problem of color nonuniformity is further exacerbated. In addition, as described above, when the phosphor is mixed with the liquid resin, the degree of precipitation increases according to the curing time, and as a result, the color coordinates may change depending on the process time, thereby increasing the defect rate and spreading the color coordinates along the package. There is a growing problem.

In addition, when the reflecting plate is installed below the light emitting chip, the phosphor mixed in the liquid resin is precipitated toward the reflecting plate to reduce the reflecting effect of the reflecting plate, and as a result, a problem of lowering the luminance of light is generated.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a light emitting diode capable of realizing uniform color light.

Another object of the present invention is to provide a light emitting diode in which the phosphor layer is easily formed.

In order to achieve the above object, the present invention comprises the steps of preparing a substrate; Forming a semiconductor layer on the substrate; Preparing a phosphor-containing powder; It provides a light emitting diode manufacturing method comprising the step of forming a phosphor layer by applying the phosphor-containing powder on the semiconductor layer. In this case, the preparing of the phosphor-containing powder may include preparing a phosphor-containing powder by mixing the powder resin and the phosphor powder. The forming of the phosphor layer by applying the phosphor-containing powder on the semiconductor layer may include applying the phosphor-containing powder on the semiconductor layer; The phosphor-containing powder may include curing at 150 degrees to 350 degrees for 2 hours to 3 hours.

In this case, the phosphor-containing powder may mix a phosphor of 5wt% to 50wt% with respect to the powder resin.
In addition, the present invention comprises the steps of forming a semiconductor layer; Preparing a phosphor-containing powder in which phosphors of 5 wt% to 50 wt% are mixed with respect to the powder resin; It provides a light emitting diode manufacturing method comprising the step of forming a phosphor layer by applying the phosphor-containing powder on the semiconductor layer.

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 embodiment of the present invention, Figure 2 is a perspective view of a phosphor layer according to a first embodiment of the present invention.

As shown in FIG. 1, the light emitting diode according to the first embodiment of the present invention includes a substrate 100, a semiconductor layer 210 formed on the substrate 100, and a phosphor formed on the semiconductor layer 210. Layer 240.

The substrate 100 refers to a conventional wafer for fabricating a light emitting diode, and includes sapphire (Al ₂ O ₃ ), silicon carbide (SiC), aluminum nitride (AlN), silicon (Si) substrate 100, and the like. It may include. However, the present invention is not limited thereto, and any substrate may be used as long as the substrate capable of forming the semiconductor layer 210.

The semiconductor layer 210 is a compound semiconductor stacked structure having a p-n junction structure and uses a phenomenon in which light is emitted by recombination of minority carriers (electrons or holes). The semiconductor layer 210 may include an active layer 210c formed between the first and second semiconductor layers 210a and 210b and the first and second semiconductor layers 210a and 210b. In this embodiment, the active layer 210c is formed in a partial region on the second semiconductor layer 210b, and the first semiconductor layer 210a is formed on the active layer 210c.

The first semiconductor layer 210a may be a P-type semiconductor layer in which holes are increased by doping an intrinsic semiconductor with P-type impurities, that is, a group III element, and the second semiconductor layer 210b may be an N-type impurity, that is, 5 in the intrinsic semiconductor. It may be an N-type semiconductor layer doped with a group element to increase the number of electrons. In this case, the P-type semiconductor layer may be formed of a P-type cladding layer and a P-type compound semiconductor layer, and the N-type semiconductor layer may be formed of an N-type cladding layer and an N-type compound semiconductor layer. In the present invention, the first semiconductor layer 210a will be described as a P-type semiconductor layer, and the second semiconductor layer 210b will be described as an N-type semiconductor layer. However, the present invention is not limited thereto, and the first semiconductor layer 210a may be an N-type semiconductor layer, and the second semiconductor layer 210b may be a P-type semiconductor layer.

The active layer 210c is a region where a predetermined bandgap and a quantum well are made to recombine electrons and holes. The emission wavelength generated by the combination of electrons and holes is changed according to the type of material constituting the active layer 210c. Therefore, it is preferable to use the semiconductor material whose composition was controlled according to the target wavelength as the active layer 210c.

The semiconductor layer 210 may be formed with an electrode 212 for applying an external power source.

The electrode 212 includes first and second electrodes 212a and 212b, and may be formed on the first and second semiconductor layers 210a and 210b, respectively. The electrode 212 is an ohmic metal making ohmic contact with the first and second semiconductor layers 210a and 210b and may be formed by applying germanium (Ge), nickel (Ni), gold (Au), or an alloy thereof. Can be.

In addition, by applying chromium (Cr) and gold (Au) or alloys thereof at predetermined positions on the first and second electrodes 212a and 212b, an electrode material for a bonding pad, that is, a wire bonding pad 214 may be formed. Can be. The wire bonding pad 214 includes first and second wire bonding pads 214a and 214b. The first and second wire bonding pads 214a and 214b serve as contacts when forming the wiring 230 for applying an external power source, and the wiring 230 is connected to the first and second electrodes 212a and 214b. 212b) to be firmly bonded.

The wiring 230 is for connecting the first and second wire bonding pads 214a and 214b with an external power input member such as a lead pattern (not shown). In this embodiment, the first and second wire bonding pads 230a are connected. , 230b). The external power input through the external power input member is transferred to the first and second wire bonding pads 214a and 214b to pass the first and second semiconductor layers through the first and second electrodes 212a and 212b. 210a and 210b and the active layer 210c. As the wiring 230, a metal having good electrical conductivity and ductility such as gold (Au) or aluminum (Al) may be used.

The phosphor layer 240 is to excite the light emitted from the semiconductor layer 210 and convert it into light having a different wavelength, and various phosphors that may be combined with the semiconductor layer 210 according to a color to be implemented. It may include. For example, in order to emit light of white light, the light emitting diode may use a phosphor layer in which a semiconductor layer emitting blue light and a yellow phosphor are mixed. The phosphor layer 240 according to the present invention is in the form of a solid having a uniform thickness of the phosphor powder cured by mixing with the powder resin. In this case, the light emitting diode according to the present exemplary embodiment illustrated in FIG. 1 is formed such that the phosphor layer 240 exposes the first electrode 212a, but is not limited thereto. It may be formed to cover part or the whole area. In addition, the phosphor layer 240 may be formed on the side surface of the semiconductor layer 210. That is, the phosphor layer 240 may be formed on a portion or the entire area of the side of the semiconductor layer 210. The phosphor 240a distributed in the phosphor layer 240 is formed to have a uniform density. That is, the phosphor 240a is evenly distributed in the x, y, z axis directions of the phosphor layer 240. Accordingly, the light emitting diode according to the present invention can implement a more uniform color than when the light emitted from the semiconductor layer 210 is excited by the phosphor layer 240. As described above, in the present invention, the light emitted from the semiconductor layer 210 may be excited by the phosphor layer 240 in which the phosphor is distributed at a uniform density, thereby having a uniform color.

In the light emitting diode according to the present embodiment, indium tin oxide (ITO) or indium zinc oxide (IZO), which are transparent electrodes, may be formed on the first semiconductor layer 210a as an electrode. have. Of course, the transparent electrode may not be formed.

Next, a manufacturing process of the light emitting diode according to the first embodiment of the present invention described above will be described with reference to the drawings. In the following description, duplicated descriptions will be omitted or briefly described.

3 to 6 are perspective views illustrating a manufacturing process of a light emitting diode according to a first embodiment of the present invention.

Referring to FIG. 3, first, a semiconductor layer 210 including first and second semiconductor layers 210a and 210b and an active layer 210c is formed on a prepared substrate 100. In this case, the semiconductor layer 210 is a metal organic chemical vapor deposition (MOCVD), a chemical vapor deposition (CVD), a plasma-enhanced chemical vapor deposition (PCVD), molecular beam growth method (Molecular Beam Epitaxy, MBE), hydride vapor phase growth (Hydride Vapor Phase Epitaxy, HVPE) and the like can be deposited and grown in a variety of ways.

Subsequently, a photoresist film is coated on the first semiconductor layer 210a and then a photoresist pattern (not shown) is formed through a photolithography process. The photoresist pattern is formed in a shape of opening a region between the semiconductor layers 210. That is, the first semiconductor layer 210a, the active layer 210c, and the second semiconductor layer 210b are etched by an etching process using the photoresist pattern as an etch mask, and a portion of the substrate 100 is exposed to expose the substrate 100. A plurality of semiconductor layers 210 are formed on the substrate. After the plurality of semiconductor layers 210 are formed as described above, the photoresist pattern is removed through a predetermined strip process. In this case, a mask film of various materials may be used instead of the photoresist pattern.

After the above process, the first semiconductor layer 210a and the active layer 210c are etched to expose the second semiconductor layer 210b of each semiconductor layer 210. To this end, a photoresist pattern (not shown) is formed on the entire structure to open a part of the first semiconductor layer. An etching process using the photoresist pattern as an etching mask is performed to etch the first semiconductor layer and the active layer. Thereafter, the photoresist pattern is removed. The etching process used in the patterning process may be a wet or dry etching process, it is effective in this embodiment to perform a dry etching using a plasma.

After removing the mask, as shown in FIG. 4, first and second electrodes 212a and 212b are formed on the first and second semiconductor layers 210a and 210b, respectively, and the first and second electrodes are formed. First and second wire bonding pads 214a and 214b are formed on the electrodes 212a and 212b, respectively. After the process, the substrate 100 is cut (A region) to separate each semiconductor layer 210.

After cutting the substrate 100 as described above, a wire bonding process is performed as shown in FIG. 5. In the wire bonding process, the first and second wire bonding pads 214a and 214b and an external power input member such as a lead pattern (not shown) are connected to the wiring 230.

Next, as shown in FIG. 6, a phosphor-containing powder 241 in which powder resin and phosphor powder are evenly mixed is coated on the first semiconductor layer 210a. In this case, the phosphor-containing powder 241 is mixed with the phosphor in the range of 5wt% to 50wt% with respect to the powder resin, and the mixed phosphor-containing powder 241 using the nozzle 250 or the like to the first semiconductor layer It apply | coats on (210a).

As described above, the phosphor-containing powder 241 is coated on the first semiconductor layer 210a and then cured to complete the light emitting diode in which the phosphor layer 240 is formed as shown in FIG. 1. In this embodiment, the phosphor-containing powder 241 is preferably cured for at least 1 hour at 150 to 350 degrees Celsius, and more preferably at 2 to 3 hours at 250 to 350 degrees Celsius. In this case, the phosphor layer 240 may be formed to cover a part or the entire area of the exposed first electrode 212a.

As described above, the present embodiment can prevent the generation of bubbles, which is a disadvantage of the phosphor molding part molded by mixing the liquid resin and the phosphor according to the prior art by using the phosphor-containing powder in which the powder resin and the phosphor are mixed. In addition, since the powder resin is used rather than the liquid resin, the above-mentioned phosphor powder may be prevented from being precipitated. In addition, the chromaticity deviation of the color coordinates by the Commission Internationale de I'Eclairage (CIE) is extremely small, and excellent yields for strict quality levels can be realized.

Next, a light emitting diode according to a second embodiment of the present invention will be described with reference to the accompanying drawings. Duplicate contents that will be described later with the above-described embodiments will be omitted or briefly described.

7 is a perspective view of a light emitting diode according to a second embodiment of the present invention.

As shown in FIG. 7, the light emitting diode according to the second embodiment of the present invention includes a semiconductor layer 310, electrodes 312 formed on and under the semiconductor layer 310, and the semiconductor layer 310. And a phosphor layer 340 formed on the substrate.

The semiconductor layer 310 includes the first and second semiconductor layers 310a and 310b and the active layer 310c as in the first embodiment of the present invention. However, in the present embodiment, unlike the first embodiment described above, the first semiconductor layer 310a and the active layer 310c are not formed in a partial region on the second semiconductor layer 310b but in the entire region.

The electrode 312 is for applying an external power source to the semiconductor layer 310 and includes first and second electrodes 312a and 312b. The first electrode 312a is formed in the first semiconductor layer 310a and may include any one of chromium (Cr), gold (Au), and chromium / gold (Cr / Au). The second electrode 312b is formed on the second semiconductor layer 310b and includes nickel (Ni), aluminum (Al), titanium (Ti), gold (Au), and indium tin oxide (ITO). It may include at least one of.

Meanwhile, the light emitting diode according to the present embodiment may further include a reflective layer 330 between the first semiconductor layer 310a and the first electrode 312a. The reflective layer 330 is for reflecting light emitted from the active layer 310c to the second semiconductor layer 310b, and any one of nickel / gold (Ni / Au), silver (Ag), and copper (Cu) It may include. Light reflected by the reflective layer 330 may be emitted to the outside through the second semiconductor layer 310b.

The phosphor layer 340 is to excite the light emitted from the semiconductor layer 310 and convert the light emitted from the semiconductor layer 310 into light having a different wavelength in the same manner as in the first embodiment, and the semiconductor layer 310 according to the color to be implemented. ) May include various phosphor layers 340. The phosphor layer 340 according to an embodiment of the present invention is in the form of a solid substance in which phosphor powder and powder resin are uniformly mixed and cured, and powder resin is formed on the second semiconductor layer 310b as in the first embodiment. It can be formed by applying and curing a phosphor-containing powder mixed with a phosphor powder. In this case, when the phosphor layer 340 is formed on the second semiconductor layer 310b, the phosphor layer 340 is formed in a shape not covering the second electrode 312b, and the density of the phosphor distributed in the phosphor layer 340 is overall. It is formed uniformly. However, the present invention is not limited thereto, and the phosphor layer 340 may cover part or the entirety of the exposed second electrode 213b.

As described above, when the light emitted from the semiconductor layer 310 is excited by the phosphor layer 340, the light emitting diode according to the present exemplary embodiment may implement a more uniform color.

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 illustrated embodiment, the horizontal and vertical light emitting diodes have been described as examples, but the present invention is not limited thereto. The present invention may be applied to all light emitting diodes using phosphors.

As described above, in the present invention, the powder resin and the phosphor powder are mixed to apply a phosphor-containing powder having a uniform phosphor distribution density on the semiconductor layer to form a phosphor layer, thereby realizing light of uniform color and the manufacturing process It is possible to provide a simple light emitting diode.

Claims (5)

Preparing a substrate; Forming a semiconductor layer on the substrate; Preparing a phosphor-containing powder; And forming a phosphor layer by coating the phosphor-containing powder on the semiconductor layer. The method according to claim 1, Preparing the phosphor-containing powder, A method of manufacturing a light emitting diode comprising mixing a powder resin and a phosphor powder to produce a phosphor-containing powder. The method according to claim 2, Forming the phosphor layer by applying the phosphor-containing powder on the semiconductor layer, Applying the phosphor-containing powder onto the semiconductor layer; And curing the phosphor-containing powder at 150 degrees to 350 degrees for 2 to 3 hours. The method according to any one of claims 1 to 3, The phosphor-containing powder is a light emitting diode manufacturing method, characterized in that the phosphor mixed with 5wt% to 50wt% relative to the powder resin. Forming a semiconductor layer; Preparing a phosphor-containing powder in which phosphors of 5 wt% to 50 wt% are mixed with respect to the powder resin; And forming a phosphor layer by coating the phosphor-containing powder on the semiconductor layer.

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