KR20070117808A - Method of fabricating light emitting diode chip - Google Patents

Abstract

A method for fabricating an LED(light emitting diode) chip is provided to emit the light generated from an active layer to the air through the lateral surface of a substrate by inclining part or all of the lateral wall of a substrate with respect to the lower surface of the lateral wall. Semiconductor layers are formed on a substrate(S103). The semiconductor layers are patterned to form at least one light emitting region(S105). The substrate is divided into a plurality of LED chips in which at least part of the lateral wall of a substrate divided by using a blade having an inclined edge is inclined with respect to the lower surface of the substrate(S107). Both surfaces of the edge of the blade can have the same inclination.

Description

Manufacturing method of light emitting diode chip {METHOD OF FABRICATING LIGHT EMITTING DIODE CHIP}

1A and 1B are cross-sectional views illustrating a general light emitting diode chip.

2 is a flowchart illustrating a method of manufacturing a light emitting diode chip according to a preferred embodiment of the present invention.

3 to 6 are views for explaining a method of manufacturing a light emitting diode chip according to an embodiment of the present invention.

7 is a view for explaining a method of manufacturing a light emitting diode chip for AC LED according to another embodiment of the present invention.

The present invention relates to a method of manufacturing a light emitting diode chip, and more particularly, to a method of manufacturing a light emitting diode chip to increase the luminous efficiency by inclining the side wall of the substrate.

A light emitting diode (LED) is a photoelectric conversion element having a structure in which a P-type semiconductor and an N-type semiconductor are joined. When a forward voltage is applied, electrons and holes move through the junction of the P-type semiconductor and the N-type semiconductor. Recombine and emit light. In this case, since the color of the emitted light is determined by the gap energy, a light emitting diode emitting light having a desired color may be manufactured according to the selection of the semiconductor material.

Such a light emitting diode can be implemented in various colors, and is widely used as a display device and a backlight for various electronic products, instrument panels, and electronic displays.

In addition, the light emitting diode consumes less power and has a longer life than a conventional incandescent lamp or a luminaire such as a fluorescent lamp, thereby replacing the existing luminaire and expanding its use area for general lighting. However, in order to use the light emitting diode for general lighting purposes, it is very important to increase the light emitting efficiency of the light emitting diode, and various techniques have been developed for this purpose.

In general, light emitting diodes are manufactured by sequentially forming semiconductor layers on a substrate and sequentially etching the formed semiconductor layers to form light emitting regions. Subsequently, the manufactured light emitting diodes are manufactured as individual light emitting diode chips through a process of separating a substrate using a diamond wheel.

1A and 1B are schematic cross-sectional views of a light emitting diode chip manufactured according to the above-described general light emitting diode chip manufacturing method.

1A is a cross-sectional view of a single light emitting diode chip, and FIG. 1B is a cross-sectional view of a light emitting diode chip for an AC LED.

Referring to the drawings, semiconductor layers 16 and 36 including lower semiconductor layers 15 and 35, active layers 17 and 37, and upper semiconductor layers 19 and 39 on substrates 11 and 31. ) Are sequentially placed. The transparent electrode layers 21 and 41 are positioned on the semiconductor layers 16 and 36, and the electrode pads 23 and the lower electrode layers 15 and 35 are disposed on the transparent electrode layers 21 and 41 and the lower semiconductor layers 15 and 35. 43) is located. A wire 45 connecting the electrode pads 43 may be formed on the LED chip for the AC LED. Meanwhile, buffer layers 13 and 33 may be interposed between the semiconductor layers 16 and 36 and the substrates 11 and 31.

After the light emitting diode is manufactured as described above, the substrate 11 and 31 of the light emitting diode chip are separated from the light emitting diode chip as shown in FIGS. 1A and 1B. It is formed vertically.

Meanwhile, in the conventional LED chip, light is emitted from the active layers 17 and 37 and light emitted upward is emitted into the air through the metal layers 21 and 41 of the upper surface of the LED chip. do.

However, of the light emitted from the active layers 17 and 37, the light emitted into the lower substrates 11 and 31 is not easily released into the air due to the difference in refractive index between the substrates 11 and 31 and the air. There is a problem that the luminous efficiency is lowered by repeating total reflection inside (11, 31). Therefore, there is a need for a method of manufacturing a light emitting diode chip in which light emitted into a substrate can be easily emitted into the air.

An object of the present invention is to provide a method of manufacturing a light emitting diode chip with improved luminous efficiency.

In order to achieve the above technical problem, the present invention discloses a light emitting diode chip manufacturing method. According to one or more exemplary embodiments, a method of manufacturing a light emitting diode chip includes preparing a substrate; Forming semiconductor layers on the substrate; Patterning the semiconductor layers to form at least one light emitting region; And separating at least a portion of the sidewall of the separated substrate into a plurality of light emitting diode chips inclined with respect to a lower surface thereof by using a blade having a slanted blade.

Here, it is preferable that both of the blade blades have the same inclination.

Further, the inclination of the blade edge is more preferably in the vertex angle of 50 degrees to 150 degrees.

The chip separating step may be performed by cutting at least a portion of the thickness using the blade in the substrate thickness direction on the lower surface side of the substrate.

In addition, the chip separation step is preferably performed by creating a groove using the blade in the thickness direction of the substrate on the lower surface side of the substrate and then cutting by applying mechanical force to both sides thereof.

Accordingly, light emitted from the active layer into the substrate can be easily emitted into the air, thereby improving the light emitting efficiency of the LED chip.

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

2 is a flowchart illustrating a method of manufacturing a light emitting diode chip according to an embodiment of the present invention, and FIGS. 3 to 5 are views illustrating a method of manufacturing a light emitting diode chip according to an embodiment of the present invention.

2 and 3, first, a substrate 211 is prepared (S101). The substrate 211 may be, for example, a sapphire (Al ₂ O ₃ ) substrate, but is not limited thereto. The substrate 211 may be variously selected according to a material of a semiconductor layer to be formed on the substrate.

Subsequently, semiconductor layers are formed on the substrate (S103). As the semiconductor layers, the lower semiconductor layer 215, the active layer 217, and the upper semiconductor layer 219 are sequentially formed. The lower semiconductor layer 215, the active layer 217, and the upper semiconductor layer 219 may be formed of a gallium nitride-based semiconductor material, that is, (B, Al, In, Ga) N. In particular, the active layer 217 is a composition element and composition ratio is determined so as to emit light of a desired wavelength, such as ultraviolet or blue light, the lower semiconductor layer 215 and the upper semiconductor layer 219 has a band gap compared to the active layer 217 It is formed of large material.

In addition, the lower semiconductor layer 215, the upper semiconductor layer 219, and the active layer 217 may include metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy, or hydride vapor phase epitaxy; HVPE) technology and the like can be grown intermittently or continuously.

The lower semiconductor layer 215 and the upper semiconductor layer 219 are n-type and p-type, or p-type and n-type, respectively. In the gallium nitride-based compound semiconductor layer, the n-type semiconductor layer may be formed by doping with silicon (Si) as an impurity, and the p-type semiconductor layer may be formed by doping with magnesium (Mg) as an impurity.

 The lower semiconductor layer 215 and / or the upper semiconductor layer 219 may be a single layer, as shown, but may have a multilayer structure. In addition, the active layer 217 may have a single quantum well or multiple quantum well structures.

In addition, before forming the lower semiconductor layer 215, a buffer layer 213 may be interposed between the semiconductor layers 216 and the substrate 211. The buffer layer 213 is formed to mitigate lattice mismatch between the substrate 211 and the lower semiconductor layer 215 to be formed thereon, and may be formed of, for example, gallium nitride (GaN) or aluminum nitride (AlN).

Subsequently, photoresist patterns defining light emitting regions are formed on the upper semiconductor layer, and the upper semiconductor layer 219, the active layer 217, and the lower semiconductor layer 215 are sequentially formed using the formed photoresist patterns as an etching mask. Etching forms light emitting regions (S105).

Referring to FIG. 4, each of the light emitting regions thus formed may include a lower semiconductor layer 215 disposed on the substrate 211 and an upper semiconductor layer 219 positioned above one region of the lower semiconductor layer 215. And an active layer 217 interposed between the lower semiconductor layer 215 and the upper semiconductor layer 219, and other regions of the lower semiconductor layer 215 are exposed.

Meanwhile, before forming the metal wires, metal layers may be formed on the upper semiconductor layer 219, ohmic contact layers may be further formed on the exposed lower semiconductor layer 215, and an upper semiconductor layer may be formed. Ohmic contact layers may also be formed on the 219, but the detailed description thereof will be omitted.

Subsequently, the substrate is cut from the lower surface of the substrate 211 by using a blade to cut at least a portion of the substrate into an inclined shape, thereby creating a groove inclined to a portion of the substrate thickness, and then mechanical forces on both sides of the generated groove. Breaking to apply a cutting (breaking), or by cutting the entire substrate in an inclined shape to create a cutting surface inclined to the entire substrate is separated into a plurality of individual light emitting diode chip (S107).

Referring to FIG. 5, the sidewalls of the substrates of the individual LED chips thus separated have an inclination θ, and the inclination becomes an inclination in which the substrate widens toward the upper surface of the substrate.

In the present invention, the blade used to separate the light emitting diode chip has an inclined blade so that the side wall of the substrate is inclined toward the lower surface side of the substrate when cutting the substrate and the inclined shape is widened toward the upper side.

6 is a cross-sectional view of a blade used in the method of manufacturing a light emitting diode according to the present invention.

Referring to the drawings, the blade (B) used to separate the substrate 211 has an inclination on both sides of the blade blade (S) formed at its end, the inclination angle of the substrate 211 has a thickness of several tens of microns to hundreds In the case of having a micro range, it is preferable that the vertex angle φ of the blade edge is manufactured to about 50 degrees to 150 degrees.

In a preferred embodiment of the present invention, since the inclination angle θ formed by the sidewall of the substrate 211 with the lower surface thereof is determined according to the inclination of the blade edge, the inclination angle θ may be in the range of 25 degrees to 75 degrees.

In other words, while rotating the blade (B) at a high speed while rotating the blade (B) along the thickness from the lower surface direction to the upper surface direction of the substrate 211, the substrate 211 is in accordance with the inclination of the blade blade The grooves are cut to form inclined grooves in the substrate 211. In this case, the thickness W and the height H of the blade blade S may be adjusted in consideration of the thickness of the substrate.

Meanwhile, although FIG. 5 illustrates a light emitting diode chip in which a part of the sidewall of the substrate 211 is inclined, according to another embodiment of the present invention, the entire sidewall of the substrate 211 is inclined in the chip separation step. It may be separated into a light emitting diode chip having a.

That is, the light emitting diode chip in which a part of the sidewall of the substrate 211 is inclined is cut while only a part of the substrate is cut while moving the blade to create a groove, and then the substrate 211 is cut by applying mechanical force to both sides of the created groove. It is formed by breaking (breaking) as possible, but the light emitting diode chip having a side wall of the entire shape of the substrate 211 is inclined so that the blade blade S passes through the whole along the thickness of the substrate 211 so that the entire substrate 211 is It is formed by cutting the entire substrate 211 at the same time as the groove is formed by cutting.

7 is a view for explaining a method of manufacturing a light emitting diode chip for AC LED according to another embodiment of the present invention.

In the method of manufacturing a light emitting diode chip for an AC LED, in the above-described single chip manufacturing method, the substrate 311 is prepared (S101), the lower semiconductor layer 315, the active layer 317 and the upper semiconductor layer 319 are prepared. Since forming the semiconductor layers to be included (S103) and patterning the semiconductor layers to form the emission regions 316 (S105) are similar, detailed description thereof will be omitted.

In the method of manufacturing a light emitting diode chip for an AC LED, after the semiconductor layers are patterned to form the emission regions 316, the transparent electrode layer 321 may be formed on the upper semiconductor layer 319, and the transparent electrode layers may be formed. 321 transmits the light generated in the active layers 317 and distributes and supplies current to the upper semiconductor layers 319.

In addition, an electrode pad 325 may be further formed on the exposed lower semiconductor layer 315, and an electrode pad 323 may also be formed on the upper semiconductor layer 319. The wiring 329 may be formed in contact with the electrode pads 323 and 325 to electrically connect the light emitting regions spaced apart from each other. The wiring 329 may be formed using an air bridge method or, in some cases, may be formed in a step cover method.

On the other hand, in order to manufacture a light emitting diode chip for an individual AC LED including the array of light emitting regions thus formed, as described above, by using a blade from the lower surface of the substrate 311 at least in the thickness direction of the substrate 311. Cutting a part in an inclined shape to create a beveled groove in a part of the thickness of the substrate and then breaking (breaking) or cutting the entire substrate in an inclined shape to create an inclined cutting surface throughout the substrate to emit light for an individual AC LED Separate with a diode chip.

Therefore, at least part or all of the sidewalls of the substrate of the separated individual LED chip for AC LED have an inclination θ, and the inclination becomes an inclination in which the substrate becomes wider toward the upper surface of the substrate.

Accordingly, in the LED chip manufactured according to the method of manufacturing the LED chip according to the embodiments of the present invention, the sidewalls of the substrates 211 and 311 are partially or entirely formed to be inclined with respect to the bottom surface, so that the substrate 211 is upward. , 311) becomes wider. The inclination of the sidewalls improves the emission efficiency of the substrates 211 and 311 of the light generated in the active layers 217 and 317.

According to embodiments of the present invention, a light emitting diode chip is manufactured such that a sidewall of the substrate is partially or wholly inclined with respect to a lower surface thereof, so that light emitted from the active layer is more easily emitted into the air from the side of the substrate, thereby providing a light emitting device. The luminous efficiency becomes high.

Claims (5)

Preparing a substrate; Forming semiconductor layers on the substrate; Patterning the semiconductor layers to form at least one light emitting region; And And separating at least a portion of the sidewall of the separated substrate into a plurality of light emitting diode chips inclined with respect to a lower surface thereof by using a blade having an inclined blade. The method according to claim 1, The blade blade has a light emitting diode chip manufacturing method, characterized in that both sides have the same inclination. The method according to claim 2, The inclination of the blade blade is a vertex angle of 50 to 150 degrees LED chip manufacturing method, characterized in that. The method according to claim 2, The chip separating step is performed by cutting at least a portion of the thickness using the blade in the substrate thickness direction on the lower surface side of the substrate. The method according to claim 2, The chip separating step may be performed by creating grooves using the blades in the thickness direction of the substrate on the lower surface side of the substrate and then cutting them by applying mechanical force to both sides thereof. .

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