KR20120000291A - Wavelength converted light emitting diode chip and method of manufacturing the same - Google Patents

Abstract

PURPOSE: A wavelength converted light emitting diode chip and a manufacturing method thereof are provided to minimize color temperature deviation according to directional angles by producing a uniform light emitting property. CONSTITUTION: A plurality of LED chips(20) is attached to the chip layout area in the upper side of a temporary supporting plate(11). Conductive bumps(28a,28b) are formed on the electrode of each LED chip. A resin encapsulation part(29') with a fluorescent substance is formed in the chip layout area to cover the conductive bumps. The resin encapsulation part containing the fluorescent substance is ground so that the conductive bumps are exposed to the upper side of the resin encapsulation part containing the fluorescent substance. A wavelength converted LED chip(30) is formed between LED chips by cutting the resin encapsulation part containing the fluorescent substance.

Description

Wavelength converting light emitting diode chip and method for manufacturing the same {WAVELENGTH CONVERTED LIGHT EMITTING DIODE CHIP AND METHOD OF MANUFACTURING THE SAME}

The present invention relates to a wavelength conversion type light emitting diode chip, and more particularly, to a wavelength conversion type light emitting diode chip capable of reducing color temperature variation according to an emission angle while implementing uniform light emitting characteristics and a method of manufacturing the same.

Light Emitting Diode (hereinafter, referred to as 'LED') is a semiconductor device that converts electrical energy into optical energy, and is composed of a compound semiconductor that emits light of a specific wavelength according to an energy band gap. Its use is expanding from the back light unit (BlU) for displays and LCDs to computer monitors.

In particular, the development of lighting LEDs requires higher current, higher light intensity and uniform light emission characteristics than conventional LEDs, and therefore, new designs and process developments are required.

Conventionally, a light emitting device package has been manufactured by applying a mixture of a phosphor and a transparent resin around a LED chip by a known method such as dispensing for white light emission. In this case, there is a problem that a difference in color characteristics such as a color temperature occurs between the white light emitted from the upper surface and the side of the chip is different from the amount of phosphor located on the upper surface and the side of the LED chip.

In addition, in the case where a cup structure is formed in the region where the LED chip is mounted and the resin is filled in the cup structure, the optical path is long due to scattering by the phosphor and thus there is a problem that the light efficiency is also lowered.

On the other hand, even in the case of forming the phosphor layer under the same conditions directly at the wafer level, there is a problem that it is difficult to ensure uniform light emission characteristics.

Specifically, even when the semiconductor epitaxial layer is grown on the same wafer under the same growth conditions, it has different emission light characteristics according to each chip region.

Therefore, when the same phosphor layer is applied, the final white LED chip has different characteristics of white light due to different emitted light characteristics, which may cause color scattering problems.

The present invention is to solve the above problems of the prior art, one object of the present invention is to provide a wavelength conversion type LED chip manufacturing method having a fluorescent film that can be uniformly coated on the surface of the chip to provide a white light corresponding to the desired color coordinate region. It is.

Another object of the present invention is to provide a wavelength conversion type LED chip manufacturing method having a fluorescent film that is uniformly coated on the chip surface and can provide white light corresponding to a desired color coordinate region.

In order to solve the above technical problem, an aspect of the present invention

Attaching a plurality of LED chips to the chip array region of the upper surface of the temporary support plate such that a surface on which at least one electrode is formed faces upward; forming a conductive bump on the electrodes of the respective LED chips; Forming a resin packaging part containing a phosphor in the chip array region to cover the surface, polishing the phosphor-containing resin packaging part to expose the conductive bumps on an upper surface of the phosphor-containing resin packaging part, and Cutting the phosphor-containing resin packaging part to form a wavelength conversion type LED chip, wherein a wavelength conversion layer obtained from the phosphor-containing resin packing part is formed on side and top surfaces of the wavelength conversion type LED chip; It provides a wavelength conversion type LED chip manufacturing method comprising the step of removing the temporary support plate from the LED chip.

Preferably, the plurality of LED chips may be selected based on the characteristics of a particular emitted light from among a plurality of LED chips obtained from at least one wafer. Here, the characteristic of the emitted light may be at least one of the peak wavelength and the light output of the emitted light.

Preferably, the temporary support plate may have a dam structure surrounding the chip arrangement region. In this case, the dam structure may have a height that is at least greater than the height of the chip on which the conductive bumps are formed.

An interval of the LED chip attached to the temporary support plate may be set larger than twice the thickness of the portion of the wavelength conversion layer to be located on the side of the LED chip.

The phosphor-containing resin package forming process may be performed by a process selected from dispensing, screen printing, spin coating, spray coating, or transfer molding.

In a particular embodiment, the plurality of LED chips comprises an insulating substrate, a semiconductor epitaxial layer having a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer sequentially formed on the insulating substrate, and the first substrate. And first and second electrodes respectively formed on the second conductive semiconductor layer.

In another embodiment, the plurality of LED chips comprises a conductive substrate, a semiconductor epitaxial layer having a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer sequentially formed on the conductive substrate, and the second It may include an electrode formed on the conductive semiconductor layer.

Another aspect of the invention is a semiconductor epitaxial layer having a substrate, a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer sequentially formed on the substrate, and at least one formed on the semiconductor epitaxial layer An electrode, a conductive bump formed on a surface of the at least one electrode, and a resin containing at least one phosphor powder, the conductive epitaxial layer being formed to surround the side surface of the substrate, wherein the conductive Provided is a wavelength conversion type LED chip including a wavelength conversion layer having an upper surface forming the same plane as an upper surface of a bump.

In one example, the substrate is an insulating substrate, and the at least one electrode may include first and second electrodes formed on the first and second conductive semiconductor layers, respectively.

Alternatively, the substrate may be a conductive substrate, and the at least one electrode may include an electrode formed on the second conductive semiconductor layer.

According to the present invention, in manufacturing the phosphor film at the chip level, it is possible to provide a phosphor film forming technology capable of improving color scattering yield and minimizing color temperature variation for each orientation by applying the entire surface to the side as well as the top surface of the chip.

In particular, by forming a fluorescent film by dividing the LED chip by wavelength and / or light output in advance, the phosphor can be uniformly coated according to the optical characteristics of the LED chip, thereby providing a high quality white LED chip corresponding to a desired target color coordinate region. It can achieve mass production through process yield and manufacturing cost reduction.

1A to 1F are cross-sectional views of processes for explaining a manufacturing process according to an embodiment of the present invention.
Figure 2 is a side cross-sectional view showing an example of an LED chip that can be used in one embodiment of the present invention.
Figure 3 is a top plan view showing a temporary support plate attached to the LED chip during the manufacturing process according to an embodiment of the present invention.
Figure 4 is a side cross-sectional view showing a wavelength conversion type LED chip according to an embodiment of the present invention.
5 is a side sectional view showing a wavelength conversion type LED chip according to another embodiment of the present invention.
6A and 6B are cross-sectional views illustrating a backlight unit according to various embodiments of the present disclosure.
7 is an exploded perspective view showing a display device according to an embodiment of the present invention.

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

1A to 1F are cross-sectional views of processes for explaining a manufacturing process according to an embodiment of the present invention.

First, the manufacturing process according to the present embodiment begins with attaching a plurality of LED chips 20 to the chip arrangement region on the upper surface of the temporary support plate 11, as shown in FIG.

The plurality of LED chips 20 may have a structure shown in FIG. 1. That is, in the LED chip 20 employed in the present embodiment, the semiconductor epitaxial layer on which the first conductive semiconductor layer 25a, the active layer 25c and the second conductive semiconductor layer 25b are formed is formed on the insulating substrate 21. It has a shir layer 25. In addition, the first and second electrodes 27a and 27b may be formed on the first conductive semiconductor layer 25a and the second conductive semiconductor layer 25b which are exposed by mesa etching.

As described above, when the electrodes 27a and 27b of both polarities are located toward the direction in which the semiconductor epitaxial layer 25 is formed, the surfaces on which the two electrodes 27a and 27b are formed are attached upward.

On the other hand, when only one electrode of the other polarity is formed on the conductive substrate and the opposite side (generally referred to as a "vertical structure light emitting element") is formed so that the surface on which the electrode on which the conductive bump is to be formed is formed is directed upward. Can be.

The plurality of LED chips 20 may be selected based on characteristics of a particular emitted light from among a plurality of LED chips obtained from at least one wafer. Here, the characteristic of the emitted light may be at least one of the peak wavelength and the light output of the emitted light.

In general, chips obtained on the same wafer also exhibit different wavelength characteristics. Therefore, when the phosphor film is collectively applied to the entire chip region at the wafer level, deviation occurs in the converted wavelength, that is, the characteristic of the white light, so that a plurality of chips do not satisfy the desired target color coordinate region.

However, in the present embodiment, since the phosphor layer forming process is performed at the chip level, an appropriate phosphor film for distinguishing chips having similar wavelength characteristics in advance and obtaining desired color coordinate characteristics can be applied, and thus, a wafer level process. It can provide an advantageous advantage in providing a high-quality wavelength conversion type LED chip corresponding to the target color coordinate region than in.

The temporary support plate 11 is not limited, but is preferably a material that is easy to separate the LED chip on which the fluorescent film is formed after the formation of the fluorescent film or a material having excellent thermal characteristics. For example, a UV curable PET film having high heat resistance Or a metal substrate such as Al or Cu having excellent thermal conductivity, or an inorganic substrate such as silicon.

As shown in FIG. 1A, the spacing D of the LED chip 20 attached to the temporary support plate 11 is the thickness of the portion of the wavelength conversion layer 29 to be positioned on the side surface of the LED chip 20. It is preferable to set larger than twice ("d" in Fig. 1E). That is, the distance D may be set in consideration of the slicing width to be removed in the cutting process of FIG. 1E.

Preferably, the temporary support plate 11 may include a dam structure 14 surrounding the chip arrangement region, as shown in FIG. 2. As shown, the LED chip 20 attached to the chip arrangement region may have an M x N arrangement to maintain a constant interval.

The dam structure 14 may have a height greater than at least the height of the chip on which the conductive bumps are formed so that the phosphor layer to be formed in FIG. 1C may cover the conductive bumps 28a and 28b.

Subsequently, as illustrated in FIG. 1B, conductive bumps 28a and 28b are formed on the electrodes 27a and 27b of the respective LED chips 20.

The conductive bumps 28a and 28b are formed to have a height greater than the desired thickness of the phosphor layer to be formed on the surface thereof. For example, the conductive bumps 28a and 28b may be formed to have a thickness of 50 to 120 μm. In order to form a bump having such a large height, the stud bumps can be laminated in two or more stages.

Next, as shown in Fig. 1C, a resin packaging portion 29 'containing phosphors is formed in the chip arrangement region.

The phosphor-containing resin packaging portion 29 'formed in this step is preferably formed to have a height H that can cover the conductive bumps 28a and 28b.

The phosphor-containing resin packaging part forming process may be performed by a process selected from dispensing, screen printing, spin coating, spray coating, and transfer molding. Among them, in the case of applying a liquid resin such as dispensing, the dam structure may play a role in determining the formation height.

Next, as shown in FIG. 1D, the phosphor-containing resin packaging part 29 'is polished so as to expose the conductive bumps 28a and 28b on the upper surface of the phosphor-containing resin packaging part 29'.

Through this process, the thickness of the resin packaging portion 29 'can be adjusted to the desired thickness over the entire area, and the bonding area e of the conductive bumps (e) can be provided to have almost the same thickness for the entire chip. ) Can be exposed on the upper surface of the phosphor resin packaging portion 29 '.

Next, as shown in FIGS. 1E and 1F, the phosphor-containing resin packaging part 29 ′ between the LED chips is cut to form a wavelength converting LED chip 30, and a wavelength converting LED chip 30. ) Is separated from the temporary support substrate (11).

The wavelength conversion type LED chip 30 obtained in this step may have a wavelength conversion layer 29 obtained from the above-mentioned phosphor-containing resin packaging part on its side and top surface.

In the wavelength conversion layer 29 provided in the wavelength conversion type LED chip, the thickness h of the portion located on the upper surface of the chip can be precisely adjusted to an appropriate thickness by a polishing process, and the thickness d of the portion located on the side of the chip. By setting the spacing D and the slicing width w at the time of attaching the LED chip 20, it is possible to obtain a precise and uniform thickness.

As such, by providing a wavelength conversion layer having a uniform thickness not only on the upper surface of the chip but also on the side surface, it is possible to improve color scattering yield and minimize color temperature variation for each direction, particularly at the chip level for each wavelength and / or light output. By dividing the chip in advance and forming a fluorescent film, an appropriate wavelength conversion layer may be provided according to the optical characteristics of the LED chip to provide a high quality white LED chip corresponding to a desired target color coordinate region.

4 is a side sectional view showing a wavelength conversion type LED chip obtained through the process shown in FIG. 1 as one embodiment of the present invention.

The wavelength conversion type LED chip 30 shown in FIG. 4 includes a substrate 21 and a first conductive semiconductor layer 25a, an active layer 25c, and a second conductive type sequentially formed on the substrate 21. A semiconductor epitaxial layer 25 having a semiconductor layer 25b.

The substrate 21 may be an insulating substrate such as a sapphire substrate. In order to form an electrode for conducting the first conductive semiconductor layer 25a, an exposed region is provided through mesa etching, and the exposed region of the first conductive semiconductor layer 25a is formed of the first electrode 27a. Form. The second electrode 27b is formed on the second conductive semiconductor layer 25b. In this way, both the bipolar electrodes 27a and 27b are located toward the same surface.

Conductive bumps 28a and 28b are formed on the surfaces of the first and second electrodes 27a and 27b, respectively. In addition, a wavelength conversion layer 29 made of a resin body 29b containing at least one phosphor powder 29a is formed. The wavelength conversion layer 29 is formed to surround the surface of the semiconductor epitaxial layer 25 and the side surface of the substrate 21.

The wavelength conversion layer 29 has an overall flat top surface to have a predetermined thickness h in the upper surface region of the chip 20, and the conductive bumps 28a and 28b have the same plane as the top surface of the wavelength conversion layer 29. It has a bonding area. In addition, the wavelength conversion layer 29 is provided to have a constant thickness d on the side of the chip 20.

As described above, the wavelength conversion type LED chip 30 provided according to the present embodiment may have the thickness of the wavelength conversion layer 29 as a whole, and the thickness thereof may be precisely adjusted, thereby reducing the color temperature difference according to the emission angle. It can be minimized.

5 is a side sectional view showing a wavelength conversion type LED chip according to another embodiment of the present invention.

The wavelength conversion type LED chip 60 shown in FIG. 5 includes a substrate 51 and a first conductivity type semiconductor layer 55a, an active layer 55c, and a second conductivity type sequentially formed on the substrate 51. A semiconductor epitaxial layer 55 having a semiconductor layer 55b.

The substrate 51 may be a conductive substrate such as a metal layer formed by plating. In this case, an electrode that is conductive to the first conductivity type semiconductor layer 55a is provided through the substrate 51. Meanwhile, the exposed region electrode 57 of the first conductivity type semiconductor layer 55a is formed.

Conductive bumps 58 are formed on the surface of the electrode 57. Further, a wavelength conversion layer 59 made of a resin body 59b containing at least one phosphor powder 59a is formed.

The wavelength conversion layer 59 is formed to surround the surface of the semiconductor epitaxial layer 55 and the side surface of the substrate 51. The wavelength conversion layer 59 has an overall flat upper surface to have a predetermined thickness h1 in the upper surface region of the chip 50, and the conductive bumps 58 have the same plane as the upper surface of the wavelength conversion layer 59. Has an area. In addition, the wavelength conversion layer 59 is provided to have a constant thickness d1 at the side of the chip 50.

The wavelength conversion type LED chip 60 according to the present embodiment (vertical structure light emitting device) also has a thickness of the wavelength conversion layer 59 as a whole, similarly to the form shown in FIG. Because it can be precisely adjusted, the color temperature difference according to the radiation angle can be minimized. As such, the phosphor film forming technology according to the present invention may be advantageously applied to light emitting diodes having various structures.

The LED chip having the wavelength conversion layer described above may be implemented as various types of packages having electrode connection structures for easy connection with external circuits, and thus may be used as LED light sources of various devices.

6A and 6B are cross-sectional views illustrating an example of a backlight unit according to various embodiments of the present disclosure.

Referring to FIG. 6A, an edge type backlight unit 1300 is illustrated as an example of a backlight unit to which a light emitting diode package according to the present invention may be applied as a light source.

The edge type backlight unit 1300 according to the present exemplary embodiment may include a light guide plate 1340 and an LED light source module 1310 provided on both side surfaces of the light guide plate 1340.

In this embodiment, the LED light source module 1310 is illustrated in the form provided on opposite sides of the light guide plate 1340, but may be provided only on one side, alternatively, additional LED light source module may be provided on the other side. .

As shown in FIG. 6A, a reflecting plate 1320 may be additionally provided under the light guide plate 1340. The LED light source module 1310 employed in the present embodiment includes a printed circuit board 1301 and a plurality of LED light sources 1305 mounted on an upper surface of the substrate 1301, wherein the LED light source 1305 has the aforementioned wavelength. It is applied to a light emitting device package employing a conversion type LED chip.

Referring to FIG. 6B, a direct backlight unit 1400 is illustrated as an example of another type of backlight unit.

The direct type backlight unit 1400 according to the present exemplary embodiment may include a light diffusion plate 1440 and an LED light source module 1410 arranged on the bottom surface of the light diffusion plate 1440.

The backlight unit 1400 illustrated in FIG. 6B may include a bottom case 1460 to accommodate the light source module under the light diffusion plate 1440.

The LED light source module 1410 employed in this embodiment includes a printed circuit board 1401 and a plurality of LED light sources 1405 mounted on an upper surface of the substrate 1401. The plurality of LED light sources 1405 are applied to the light emitting device package employing the above-described wavelength conversion type LED chip.

7 is an exploded perspective view showing a display device according to an embodiment of the present invention.

The display device 2400 illustrated in FIG. 7 includes a backlight unit 2200 and an image display panel 2300 such as a liquid crystal panel. The backlight unit 2200 includes a light guide plate 224 and an LED light source module 2100 provided on at least one side of the light guide plate 2240.

In the present exemplary embodiment, the backlight unit 2200 may further include a bottom case 2210 and a reflector 2220 disposed under the light guide plate 2120 as shown.

In addition, according to the demand for various optical properties, the light guide plate 2240 and the liquid crystal panel 2300 may include various types of optical sheets 2260 such as a diffusion sheet, a prism sheet, or a protective sheet.

The LED light source module 2100 may be mounted on at least one side of the light guide plate 2240 and mounted on the printed circuit board 2110 to inject light into the light guide plate 2240. A plurality of LED light source 2150 is included. The plurality of LED light sources 2150 may be light emitting device packages including the above-described wavelength converting LED chip. The plurality of LED light sources employed in the present embodiment may be side view type light emitting device packages in which side surfaces adjacent to the light emitting surface are mounted.

As described above, the above-described phosphor may be applied to a package of various mounting structures to be applied to an LED light source module that provides various types of white light. The light emitting device package or the light source module including the same may be applied to various types of display devices or lighting devices.

The present invention is not limited by the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims, and various forms of substitution, modification, and within the scope not departing from the technical spirit of the present invention described in the claims. It will be apparent to those skilled in the art that changes are possible.

Claims (17)

Attaching a plurality of LED chips such that a surface on which at least one electrode is formed is upward in a chip array region of an upper surface of a temporary support plate;
Forming a conductive bump on an electrode of each LED chip;
Forming a resin packaging part containing phosphors in the chip array region to cover the conductive bumps;
Polishing the phosphor-containing resin packaging part to expose the conductive bumps on the upper surface of the phosphor-containing resin packaging part;
Cutting the phosphor-containing resin packaging part between the LED chips to form a wavelength conversion type LED chip, wherein a wavelength conversion layer obtained from the phosphor-containing resin packing part is formed on the side and the upper surface of the wavelength conversion type LED chip; ; And
And removing the temporary support plate from the wavelength converting LED chip.
The method of claim 1,
The plurality of LED chips, the wavelength conversion type LED chip manufacturing method, characterized in that selected from the plurality of LED chips obtained from at least one wafer on the basis of the characteristics of the light emitted.
The method of claim 2,
The emission light is characterized in that the wavelength conversion type LED chip manufacturing method characterized in that at least one of the peak wavelength and the light output of the emitted light.
The method of claim 1,
The temporary support plate is a wavelength conversion type LED chip manufacturing method comprising a dam structure surrounding the chip array region.
The method of claim 4, wherein
The dam structure is a wavelength conversion type LED chip manufacturing method characterized in that it has a height at least greater than the height of the chip on which the conductive bump is formed.
The method of claim 1,
The spacing of the LED chip attached to the temporary support plate, the wavelength conversion type LED chip manufacturing method, characterized in that greater than twice the thickness of the portion of the wavelength conversion layer to be located on the side of the LED chip.
The method of claim 1,
The temporary support plate is a wavelength conversion type LED chip manufacturing method, characterized in that the UV curable PET film.
The method of claim 1,
Forming the phosphor-containing resin packaging portion, the wavelength conversion type LED chip manufacturing method characterized in that it is performed by a process selected from dispensing, screen printing, spin coating, spray coating and transfer molding.
The method of claim 1,
The plurality of LED chips include an insulating substrate, a semiconductor epitaxial layer having a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer sequentially formed on the insulating substrate, and the first and second conductive types. A wavelength conversion type LED chip manufacturing method comprising a first electrode and a second electrode formed on the semiconductor layer, respectively.
The method of claim 1,
The plurality of LED chips includes a conductive substrate, a semiconductor epitaxial layer having a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer sequentially formed on the conductive substrate, and on the second conductive semiconductor layer. A wavelength conversion type LED chip manufacturing method comprising an electrode formed on.
Board;
A semiconductor epitaxial layer having a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer sequentially formed on the substrate;
At least one electrode formed on the semiconductor epitaxial layer;
A conductive bump formed on a surface of the at least one electrode; And
The semiconductor epitaxial layer is formed to surround the side surface of the substrate, and includes a resin containing at least one phosphor powder, the wavelength conversion layer having a top surface that is the same plane as the top surface of the conductive bumps. Wavelength converting LED chip.
The method of claim 11,
The substrate is an insulating substrate, wherein the at least one electrode includes a first and second electrodes formed on the first and second conductive semiconductor layer, respectively.
The method of claim 11,
The substrate is a conductive substrate, the at least one electrode is a wavelength conversion type LED chip, characterized in that it comprises an electrode formed on the second conductive semiconductor layer.
A light emitting device package comprising a wavelength conversion type LED chip manufactured by the method according to any one of claims 1 to 10.
Light guide plate; And
And a LED light source module disposed on at least one side of the light guide plate to provide light inside the light guide plate.
The LED light source module includes a LED light source having a circuit board and a wavelength conversion type LED chip mounted on the circuit board and manufactured by the method according to any one of claims 1 to 10. Light source device.
An image display panel for displaying an image; And
And a backlight unit having the surface light source device according to claim 15 for providing light to the image display panel.
LED light source module; And
And a diffusion sheet disposed on the LED light source module and uniformly diffusing the light incident from the LED light source module.
The LED light source module includes an LED light source having a circuit board and a wavelength conversion type LED chip mounted on the circuit board and manufactured by the method according to any one of claims 1 to 10. Device.

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