KR101021416B1 - Light emitting diodes having wavelength conversion pillars and a manufacturing method thereof - Google Patents

Abstract

Provided are a light emitting diode and a light emitting diode manufacturing method. The light emitting diode is disposed on an upper surface of the first type semiconductor layer and a first type semiconductor layer disposed on the upper surface of the substrate, and exposes at least a portion of the upper surface of the first type semiconductor layer. A light emitting structure having a layer, except for the first type electrode and the second type electrode, the first type electrode and the second type electrode, respectively disposed on upper surfaces of the first type semiconductor layer and the second type semiconductor layer. A transmissive protective layer disposed on a substrate and having an upper surface at a level higher than an upper surface level of the second type semiconductor layer, and exposing upper surfaces of the first type electrode and the second type electrode, and the transparent protective layer; Wavelength conversion pillars are disposed in each of the plurality of through holes penetrating the edge of the substrate.

Light Emitting Diodes, Wafer Level Light Emitting Diodes, Wavelength Conversion Columns

Description

Light emitting diodes having wavelength conversion pillars and a method for manufacturing the same

The present invention relates to a light emitting diode, and more particularly, to a light emitting diode having a wavelength conversion pillar and a manufacturing method thereof.

A light emitting diode (LED) is a semiconductor device that converts current into light and is mainly used as a light source of a display device. These light emitting diodes are very small compared to the conventional light sources, have very low power consumption, long lifespan, and fast reaction speed. In addition, it does not emit harmful electromagnetic waves such as ultraviolet rays, and is environmentally friendly since it does not use mercury and other discharge gases.

Such a light emitting diode converts the wavelength of light emitted from the light emitting diode chip using a wavelength conversion material. In order to change the light of the LED chip using the wavelength conversion material, the wavelength conversion material should be formed on the entire light emitting surface of the LED chip.

To this end, conventionally, individualized light emitting diode chips were manufactured by dicing, and wavelength converting materials were disposed on emission surfaces including upper and side surfaces of each light emitting diode chip.

However, when the wavelength conversion material is formed on the light emitting surface of the light emitting diode in this manner, the wavelength conversion may not be uniform along with an increase in manufacturing time and manufacturing cost.

The technical problem to be solved by the present invention is to form a wavelength conversion material in the fab process, it is easy to control the quality of optical properties such as color temperature, color rendering, etc., the wavelength conversion uniformity for each orientation is improved, mass production is easy A light emitting diode containing a wavelength conversion material and a method of manufacturing the same are provided.

Technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above technical problem, an aspect of the present invention provides a light emitting diode. The light emitting diode is disposed on an upper surface of the first type semiconductor layer and a first type semiconductor layer disposed on the upper surface of the substrate, and exposes at least a portion of the upper surface of the first type semiconductor layer. A light emitting structure having a layer, except for the first type electrode and the second type electrode, the first type electrode and the second type electrode, respectively disposed on upper surfaces of the first type semiconductor layer and the second type semiconductor layer. A transmissive protective layer disposed on a substrate and having an upper surface at a level higher than an upper surface level of the second type semiconductor layer, and exposing upper surfaces of the first type electrode and the second type electrode, and the transparent protective layer; Wavelength conversion pillars are disposed in each of the plurality of through holes penetrating the edge of the substrate.

The wavelength conversion pillars may be arranged in the form of a plurality of columns in the direction of the edge of the substrate, wherein the wavelength conversion pillars may be alternately arranged each wavelength conversion pillar.

The light emitting diode may further include a wavelength conversion material film disposed on a lower surface of the substrate. The substrate may include a plurality of grooves on a bottom surface thereof, and the wavelength conversion material layer may be disposed in the grooves. The light transmissive protective layer may include a wavelength conversion material and the light emitting diode may further include a reflective layer disposed on a lower surface of the substrate.

The light emitting structure is a device that emits blue light or ultraviolet light, and the wavelength conversion column may contain at least one material selected from the group consisting of a yellow conversion material, a red conversion material, a green conversion material, and a blue conversion material.

Another aspect of the present invention provides a light emitting diode manufacturing method for achieving the above technical problem. The light emitting diode manufacturing method includes a first type semiconductor layer disposed on an upper surface of a substrate and a second layer disposed on an upper surface of the first type semiconductor layer and exposing at least a portion of an upper surface of the first type semiconductor layer. Providing a light emitting structure having a type semiconductor layer, forming a first type electrode and a second type electrode on top surfaces of the first type semiconductor layer and the second type semiconductor layer, the first type electrode and Forming a transmissive protective layer on the substrate other than the second type electrode, the upper surface having a level higher than that of the second type semiconductor layer and exposing the top surfaces of the first type electrode and the second type electrode; Forming a plurality of through holes penetrating through the transmissive protective layer and the edge of the substrate; and inserting wavelength converting materials into the through holes, respectively, to form wavelength converting columns. .

The wavelength converting material further contains a cured material in which curing occurs by light, heat, or high frequency. The light emitting diode manufacturing method includes introducing the wavelength converting material into the through hole, and then converting the wavelength converting material into light, heat, or the like. The method may further include exposing to high frequency. The light may be light applied from a mechanism for generating light or light generated from the light emitting structure. The through holes may be formed using a laser drill, wet etching, or dry etching.

The light emitting diode manufacturing method may further include forming a wavelength conversion film on a lower surface of the substrate. The light emitting diode manufacturing method may further include forming a reflective layer on a lower surface of the substrate.

The light emitting diode manufactured as described above may form the wavelength conversion material on the upper surface, the lower surface, and both side surfaces of the light emitting structure in the fab process, and thus, the overall manufacturing time of the light emitting diode through the wavelength conversion material such as a white light emitting diode. It is possible to reduce the quality, easy management of optical characteristics such as color temperature, color rendering, etc., improve uniformity of wavelength conversion for each direction, and facilitate mass production.

In addition, since the substrate is used as a frame, which is a skeleton of the package, and all processes can be performed in a substrate or wafer state, a wafer level LED package can be implemented. As a result, manufacturing cost can be reduced.

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 described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Like numbers refer to like elements throughout.

1A to 1F are cross-sectional views illustrating a method of manufacturing a light emitting diode according to an embodiment of the present invention, and FIG. 2 is a plan view illustrating the top surface of FIG. 1F. The cross section of the light emitting diode shown in FIG. 1F corresponds to the cross section taken along cut line A-A of FIG. 2. Hereinafter, only the unit cell of the light emitting element is shown.

Referring to FIG. 1A, a first type semiconductor layer 12 is formed on the substrate 10. The substrate 10 may be a substrate made of a light transmissive material. The substrate 10 may be an Al ₂ O ₃ (sapphire), SiC, GaAs, InP, AlN or GaN substrate. Preferably, the substrate 10 may be an Al ₂ O ₃ substrate. The substrate 10 may include a unit substrate on which a single device is formed or a wafer on which a plurality of devices are formed.

The first type semiconductor layer 12 may be a group III-V compound semiconductor layer or a group II-VI compound semiconductor layer implanted with a first type impurity, for example, an n-type impurity. In detail, the first type semiconductor layer 12 may be a GaN layer, a GaAs layer, or an InGaAs layer.

A buffer layer (not shown) may be further disposed between the substrate 10 and the first type semiconductor layer 12 to reduce lattice defects between the substrate 10 and the first type semiconductor layer 12. The buffer layer may be an AlN layer, an InP layer, or a GaN layer.

An active layer 14 may be formed on the first semiconductor layer 12. The active layer 14 may have a quantum dot structure or a multi quantum well structure.

The light emitting structure S may be formed by forming the second type semiconductor layer 16 on the active layer 14. The second type semiconductor layer 16 may be a III-V compound semiconductor layer or a II-VI compound semiconductor layer implanted with a second type impurity, that is, a p-type impurity. In detail, the second type semiconductor layer 16 may be a GaN layer, a GaAs layer, or an InGaAs layer.

The first type semiconductor layer 12, the active layer 14, and the second type semiconductor layer 16 may be formed using a metal organic chemical vapor deposition (MOCVD) technique or a molecular beam epitaxy (MBE) technique. .

Referring to FIG. 1B, the second type semiconductor layer 16, the active layer 14, and the first type semiconductor layer 12 are mesa-etched to expose edge portions of the upper surface of the substrate 10. A portion of the second type semiconductor layer 16 and the active layer 14 are etched to expose at least a portion of the upper surface of the first type semiconductor layer 12. In this case, a portion of the upper surface of the first type semiconductor layer 12 may also be etched.

Accordingly, the light emitting structure S is disposed on the first type semiconductor layer 12 and the top surface of the first type semiconductor layer 12 disposed on the top surface of the substrate 10, but the first type semiconductor layer 12 is disposed on the first surface of the substrate 10. The active layer 14 and the second type semiconductor layer 16 exposing at least a portion of the upper surface of the type semiconductor layer 12 may be provided. The light emitting structure S manufactured as described above may be a device emitting blue light or ultraviolet light.

Referring to FIG. 1C, a first type electrode 22 and a second type electrode 24 are formed on upper surfaces of the first type semiconductor layer 12 and the second type semiconductor layer 16, respectively. In this case, upper surface levels of the first type electrode 22 and the second type electrode 26 may be formed to be the same.

In addition, a transparent conductive film (not shown) is further added between the first type semiconductor layer 12 and the first type electrode 22, and between the top surface of the second type semiconductor layer 16 and the second type electrode 24, respectively. It may include. The transparent conductive film may contain ITO, IZO or AZO.

The first type electrode 22 and the second type electrode 26 may be formed of any one of Cr, Ni, or Ti, and a mixed layer of any one of Au, Al, Cu, Mo, W, Ag, Sn, or Pd. Can be. In addition, a surface of the electrodes 22 and 24 may further include a conductive material layer (not shown) that is well wetted with solder. The electrically conductive material layer may be SnBi, PbSn, SnAgCu, SnAgCuBi, AuSn, Sn, or In.

The first type electrode 22, the second type electrode 26, the conductive layer (not shown), and the transparent conductive film (not shown) may be sputtered, electron beam deposition, thermal deposition, pulse laser deposition, or laser molecular beam deposition. Can be used.

Referring to FIG. 1D, an upper surface of the first type electrode 22 and the second type electrode 24 on the substrate 10 except for the first type electrode 22 and the second type electrode 24. A transmissive protective layer 26 is formed to expose the film. In this case, the transparent protective layer 26 may be formed to have an upper surface of a level higher than the upper surface level of the active layer 14.

The transparent protective layer 26 may not only serve to protect the light emitting structure S, but also serve as a support. In addition, the transparent protective layer 26 may contain an insulating material to electrically insulate the first type semiconductor layer 12 and the second type semiconductor layer 16 from each other.

The transparent protective layer 26 includes a silicon oxide layer, a silicon nitride layer, a boro-phosphor silicate glass (BPSG) layer, a spin on glass (SOG) layer, a benzocyclobutene (BCB) layer, a polyimide (PI) layer, and a silicone polymer (silicone). It may be a polymer layer or an epoxy resin layer.

The transmissive protective layer 26 may be formed using a wet coating method using a mask, or after forming a translucent material film using a wet coating method, and then using a planarization apparatus, an upper surface of the translucent material film may be removed.

As a result, the first type electrode 22 and the second type electrode 24 may be exposed between the transparent protective layer 26.

Referring to FIG. 1E, wavelength converting pillars 32 are formed in a plurality of through holes penetrating through the transparent protective layer 26 and the edge of the substrate 10.

The wavelength conversion columns 52 may be arranged in one or more columns to maximize the wavelength conversion effect. In this case, the wavelength conversion pillars 52 may alternately arrange the wavelength conversion pillars 52 so that the optical paths of each other are the same.

The wavelength conversion column 52 forms a plurality of through holes penetrating the edges of the transparent protective layer 26 and the substrate 10, and introduces a liquid wavelength conversion material into the through holes, respectively. Can be formed. In this case, the liquid wavelength converting material may be filled in the through holes by capillary action.

In addition, the wavelength conversion material further contains a curing material, thereby shortening the curing time. Specifically, the cured material may be a material that is cured by light, heat, or high frequency. As one example, the cured material may be a silicone resin, an epoxy resin, an acrylic resin, a urethane resin, or a photoresist.

Accordingly, the wavelength conversion material may be quickly cured by an external light source, heat, or high frequency. In this case, the external light source may include a light source generated by applying an electric field to the light emitting structure S, as well as a light source irradiated using a mechanism for generating light. The through holes may be formed using a laser drill or an etching process such as wet etching or dry etching.

The wavelength conversion pillar 32 may contain at least one material selected from the group consisting of a yellow conversion material, a red conversion material, a green conversion material, and a blue conversion material. Specifically, when the light emitting structure S generates ultraviolet light, the wavelength conversion pillar 32 may contain red, green, and blue converting materials, and when the light emitting structure S generates blue light. The wavelength conversion pillar 32 may contain a yellow conversion material. Accordingly, the light emitting diode of the final structure may emit white light.

The blue converting material is a phosphor or a blue wire such as Sr (PO) Cl: Eu, SrMgSiO: Eu, BaMgSiO: Eu, BaMgAlO: Eu, SrPO: Eu, SrSiAlON: Eu (Fe ₄ [Fe (CN) ₆ ] ₃ ), It may be a pigment such as cobalt blue (CoO-Al ₂ O ₃ ).

The green conversion material is BaSiO: Eu, SrSiO: Eu, SrAlO: Eu, SrAlO: Eu, SrGaS: Eu, SrSiAlON: Eu, (Ca, Sr, Ba) SiNO: Eu, YSiON: Tb, YSiON: Tb, GdSiON: Phosphor of Tn or chromium oxide (Cr ₂ O ₃ ), chromium hydroxide (Cr ₂ O (OH) ₄ ), basic copper acetate (Cu (C ₂ H ₃ O ₂ ) -2Cu (OH) ₂ ), cobalt green ( It may be a pigment such as Cr ₂ O ₃ -Al ₂ O ₃ -CoO).

The red converting material may be a sulfide-based or nitride-based phosphor or a pigment such as iron oxide (Fe ₂ O ₃ ), lead tetraoxide (Pb ₃ O ₄ ), or mercury sulfide (HgS). Specifically, the sulfide phosphor may be SrS: Eu or CaS: Eu, and the nitride phosphor is SrSiN: Eu, CaSiN: Eu, CaAlSiN, (Ca, Sr, Ba) SiN: Eu, LaSiN: Eu or Sr -α-SiAlON.

The yellow conversion material may be a pigment such as YAG-based (yttrium aluminum garnet), silicate-based phosphor or lead chromate (PbCrO ₄ ), zinc chromate (ZnCrO ₄ ), sulfide-cadmium-zinc sulfide (CdS-ZnS). Specifically, the YAG-based phosphor may be YAG: Ce, TbYAG: Ce, GdYAG: Ce or GdTbYAG: Ce, and the silicate-based phosphor may be methyl silicate, ethyl silicate, magnesium aluminum silicate, or aluminum silicate.

The wavelength conversion column 52 is preferably formed to 100nm, the diameter of the wavelength conversion column 52 can be adjusted to control the wavelength conversion effect.

1F and 2, a wavelength converting material film 34 is disposed on a lower surface of the substrate 10 to form a light emitting diode. The wavelength conversion material film 34 is formed as a single layer on the bottom surface of the substrate 10 or after forming a plurality of grooves on the bottom surface of the substrate 10, the wavelength conversion material in the grooves. It may be formed by filling.

The light emitting diodes manufactured as described above are separated by dicing including sawing, cleaving, scribing, breaking, laser dicing, and the like, and are unit light emitting diodes. Can be individualized into As described above, when the lower surface of the substrate 10 has a concave-convex surface by the grooves, when the unit light emitting diode is mounted in the shape of a chip, it is possible to prevent total reflection and improve external quantum efficiency.

In addition, the light emitting diode manufactured as described above may form the wavelength conversion material on the side surface and the bottom surface of the light emitting structure in the fab process, thereby reducing the manufacturing time of the light emitting diode and facilitate mass production.

In addition, since the substrate is used as a frame, which is a skeleton of the package, and all processes can be performed in a substrate or wafer state, a wafer level LED package can be implemented. As a result, manufacturing cost can be reduced.

3 is a cross-sectional view illustrating a structure of a light emitting diode according to another embodiment of the present invention. It is similar to the light emitting diode described with reference to FIGS. 1A to 1F except as described later.

Referring to FIG. 3, the light emitting diode is disposed on the first type semiconductor layer 12 disposed on the top surface of the substrate 10 and the top surface of the first type semiconductor layer 12. A light emitting structure S having a second type semiconductor layer 16 exposing at least a portion of the upper surface of the semiconductor layer 12 is provided. In this case, the active layer 14 may be positioned between the first type semiconductor layer 12 and the second type semiconductor layer 16.

The substrate 10 may include wavelength converting columns 32 disposed in a plurality of through holes penetrating both edges, and a reflective layer 36 may be positioned on a lower surface of the substrate 10. As an example, the reflective layer 36 may be an Ag layer or an Al layer.

The reflective layer 36 may increase the amount of the light source emitted to the upper surface of the light emitting structure S by reflecting the light emitted downward in the light source emitted from the light emitting structure S, the light extraction effect Can be improved.

The first type electrode 22 and the second type electrode 24 may be disposed on upper surfaces of the first type semiconductor layer 12 and the second type semiconductor layer 16, respectively. On the substrate 10 except for the second type electrode 24 and the second type semiconductor layer 16, the first type electrode 22 and the second type have a top surface of a level higher than that of the second type semiconductor layer 16. A transmissive protective layer 26 may be disposed to expose the top surface of the type electrode 24. In this case, the transparent protective layer 26 may contain a wavelength conversion material. The wavelength conversion material may be formed using the same material as the wavelength conversion material pillar 32.

The light-transmissive protective layer 26 may include a wavelength conversion material to convert light emitted to the upper surface into another wavelength.

4 is a cross-sectional view illustrating a surface mount light emitting diode package according to an embodiment of the present invention.

Referring to FIG. 4, a unit light emitting diode is flipped and disposed on a circuit board CB including an insulating coating layer 101 and a plurality of bonding pads 102 disposed on a base board 100. The unit light emitting diode may be a unit light emitting diode described with reference to FIGS. 1A to 1F and 2.

The unit light emitting diodes may be electrically connected to the bonding pads 102 and the electrodes 22 and 24 exposed on the bottom surface of the unit light emitting diodes, respectively, by the conductive bonding material 110.

The circuit board CB may be a board made of silicon, metal, ceramic material, FR4, etc. The bonding pads may be metal pads of Au, Ag, Cr, Ni, Cu, Zn, Ti, or Pd. The conductive bonding material 110 may be the same material as the bonding pad or a thermosetting adhesive containing Ag or a solder material such as SnBi, PbSn, SnAgCu, SnAgCuBi, AuSn, Sn, or In. The insulating coating layer 101 may be omitted.

5 is a cross-sectional view illustrating a wire bonded light emitting diode package according to another embodiment of the present invention.

Referring to FIG. 5, a unit light emitting diode is disposed on a package lead frame including a support 202, a first electrode 204, a second electrode 206, and the like. The light emitting diode may be a unit light emitting diode described with reference to FIG. 3.

The unit light emitting diode may be attached to the support part 202 through a thermally conductive adhesive material 206. The electrode parts 204 and 206 and the electrodes 22 and 24 exposed in the upper surface of the unit light emitting diode may be electrically connected to each other by a conductive wire 120.

As mentioned above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications and changes may be made by those skilled in the art within the spirit and scope of the present invention. You can change it.

1A to 1F are cross-sectional views illustrating a method of manufacturing a light emitting diode according to an embodiment of the present invention.

FIG. 2 is a plan view illustrating the top surface of FIG. 1F.

3 is a cross-sectional view illustrating a structure of a light emitting diode according to another embodiment of the present invention.

4 is a cross-sectional view illustrating a surface mount light emitting diode package according to an embodiment of the present invention.

5 is a cross-sectional view illustrating a wire bonded light emitting diode package according to another embodiment of the present invention.

Claims (13)

A first type semiconductor layer disposed on an upper surface of the substrate and a second type semiconductor layer disposed on an upper surface of the first type semiconductor layer and exposing at least a portion of the upper surface of the first type semiconductor layer; Light emitting structure; First and second type electrodes respectively disposed on upper surfaces of the first type semiconductor layer and the second type semiconductor layer; It is disposed on the substrate except for the first type electrode and the second type electrode, and has an upper surface having a level higher than that of the upper surface of the second type semiconductor layer, and an upper surface of the first type electrode and the second type electrode. A translucent protective layer exposing the light; And And a wavelength conversion pillar disposed in each of the plurality of through holes penetrating through the transparent protective layer and the edge portion of the substrate. The method of claim 1, The wavelength conversion pillars are arranged in the form of a plurality of columns in the direction of the edge of the substrate. The method of claim 2, The wavelength conversion pillars are light emitting diodes, each wavelength conversion pillar is arranged alternately. The method of claim 1, The light emitting diode further comprising a wavelength conversion material film disposed on the lower surface of the substrate. The method of claim 4, wherein The substrate is provided with a plurality of grooves on the lower surface, And the wavelength conversion material film is disposed in the grooves. The method of claim 1, The translucent protective layer contains a wavelength conversion material, And a reflective layer disposed on the bottom surface of the substrate. The method of claim 1, The light emitting structure is a device emitting blue light or ultraviolet light, The wavelength conversion column includes at least one material selected from the group consisting of a yellow conversion material, a red conversion material, a green conversion material and a blue conversion material. A first type semiconductor layer disposed on an upper surface of the substrate and a second type semiconductor layer disposed on an upper surface of the first type semiconductor layer and exposing at least a portion of the upper surface of the first type semiconductor layer; Providing a light emitting structure; Forming a first type electrode and a second type electrode on upper surfaces of the first type semiconductor layer and the second type semiconductor layer, respectively; An upper surface having a level higher than that of the upper surface of the second type semiconductor layer on the substrate except for the first type electrode and the second type electrode, and exposing the upper surfaces of the first type electrode and the second type electrode; Forming a light transmitting protective layer; Forming a plurality of through holes penetrating through the transparent protective layer and the edge of the substrate; And And inserting wavelength converting materials into the through holes, respectively, to form wavelength converting pillars. The method of claim 8, The wavelength conversion material further contains a cured material that hardening occurs by light, heat or high frequency, And introducing the wavelength conversion material into the through-hole, and then exposing the wavelength conversion material to light, heat, or high frequency. 10. The method of claim 9, Wherein the light is light applied from a mechanism for generating light or light generated from the light emitting structure. The method of claim 8, The through-holes are formed using a laser drill, wet etching or dry etching. The method of claim 8, A method of manufacturing a light emitting diode, the method comprising: forming a wavelength conversion film on a lower surface of the substrate. The method of claim 8, And forming a reflective layer on a lower surface of the substrate.

Images