KR102225477B1 - Method for manufacturing a light emitting diode chip and a light emitting diode chip - Google Patents

Abstract

An object of the present invention is to provide a method of manufacturing a light emitting diode chip and a light emitting diode chip capable of obtaining sufficient luminance.
A method of manufacturing a light emitting diode chip, comprising a laminate layer in which a plurality of semiconductor layers including a light emitting layer are formed on a transparent substrate for crystal growth, and each partitioned by a plurality of scheduled division lines crossing each other on the surface of the laminate layer. After performing the wafer preparation process of preparing a wafer in which each LED circuit is formed in the region, a transparent substrate processing process of forming a plurality of grooves corresponding to each LED circuit of the wafer on the surface of the transparent substrate, and the transparent substrate processing process , An integrated process of forming an integrated wafer by attaching the surface of the transparent substrate to the rear surface of the wafer, and cutting the wafer along with the transparent substrate along the line to be divided to divide the integrated wafer into individual light emitting diode chips. It characterized in that it includes a dividing process.

Description

Light emitting diode chip manufacturing method and light emitting diode chip {METHOD FOR MANUFACTURING A LIGHT EMITTING DIODE CHIP AND A LIGHT EMITTING DIODE CHIP}

The present invention relates to a method of manufacturing a light emitting diode chip and a light emitting diode chip.

A laminate layer in which a plurality of n-type semiconductor layers, light emitting layers, and p-type semiconductor layers are stacked is formed on the surface of a crystal growth substrate such as a sapphire substrate, a GaN substrate, or a SiC substrate, and a plurality of division scheduled lines intersecting the laminate layer are formed. A wafer in which a plurality of light emitting devices such as LEDs (Light Emitting Diode) is formed in an area partitioned by the device is cut along a line to be divided and divided into individual light emitting device chips, and the divided light emitting device chips are mobile phones, personal computers, and It is widely used in various electric devices such as lighting equipment.

Since the light emitted from the light emitting layer of the light emitting device chip has isotropic property, it is irradiated to the inside of the substrate for crystal growth, and light is also emitted from the back and side surfaces of the substrate. However, among the light irradiated to the inside of the substrate, light having an incidence angle greater than or equal to the critical angle at the interface with the air layer is totally reflected at the interface, trapped inside the substrate, and is not emitted from the substrate to the outside, thereby reducing the luminance of the light emitting device chip. There is a problem to cause.

In order to solve this problem, in order to suppress the light emitted from the light-emitting layer from being trapped inside the substrate, a light-emitting diode (LED) is designed to improve luminance by attaching a transparent member to the back surface of the substrate. It is described in Japanese Patent Laid-Open No. 2014-175354.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2014-175354

However, in the light emitting diode disclosed in Patent Document 1, there is a problem that the luminance is slightly improved by attaching a transparent member to the back surface of the substrate, but a sufficient luminance cannot be obtained.

The present invention has been made in view of these points, and an object thereof is to provide a method of manufacturing a light emitting diode chip and a light emitting diode chip capable of obtaining sufficient luminance.

According to the invention of claim 1, a method of manufacturing a light emitting diode chip, comprising a laminate layer in which a plurality of semiconductor layers including a light emitting layer are formed on a first transparent substrate for crystal growth, and crossing each other on the surface of the laminate layer. A wafer preparation step of preparing a wafer in which LED circuits are formed in each area divided by a plurality of scheduled division lines, and a transparent substrate forming a plurality of grooves on the surface of a second transparent substrate corresponding to each of the LED circuits of the wafer After performing the processing step and the transparent substrate processing step, an integrated step of forming an integrated wafer by attaching the surface of the second transparent substrate to the back surface of the wafer, and the second transparent wafer along the line to be divided There is provided a method of manufacturing a light emitting diode chip comprising a dividing step of cutting the integrated wafer together with a substrate to divide the integrated wafer into individual light emitting diode chips.

Preferably, the cross-sectional shape of the groove formed in the transparent substrate processing step is any one of a triangular shape, a square shape, or a semicircular shape. Preferably, the groove formed in the transparent substrate processing step is formed by any one of a cutting blade, etching, sand blast, and laser.

Preferably, the second transparent substrate is formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin, and in the integration step, the second transparent substrate is adhered to the wafer with a transparent adhesive.

According to the invention as set forth in claim 5, the light emitting diode chip includes a light emitting diode having an LED circuit formed on a surface thereof, and a transparent member affixed to the back surface of the light emitting diode, and a groove on the adhesion surface of the transparent member to the light emitting diode A light emitting diode chip is provided.

In the light emitting diode chip of the present invention, since a groove is formed on the surface of the transparent member attached to the rear surface of the LED, in addition to increasing the surface area of the transparent member, light irradiated from the light emitting layer of the LED and incident on the transparent member is grooved. Due to the complicated refraction at the part, the ratio of light whose incident angle at the interface between the transparent member and the air layer is greater than or equal to the critical angle when emitted from the transparent member decreases, and the amount of light emitted from the transparent member increases, thereby improving the luminance of the LED chip. do.

1 is a front perspective view of an optical device wafer.
Fig. 2A is a perspective view showing a process of processing a transparent substrate, and Figs. 2B to 2D are cross-sectional views showing a formed groove shape.
Fig. 3(A) is a perspective view showing an integration process in which a transparent substrate having a plurality of grooves extending in a first direction on its surface is adhered to the rear surface of the wafer to be integrated, and Fig. 3B is a perspective view of the integrated wafer. .
Fig. 4 is a perspective view showing an integration process in which a transparent substrate having a plurality of grooves on its surface extending in a first direction and a second direction orthogonal to the first direction is attached to the rear surface of the wafer to be integrated.
5 is a perspective view showing a supporting process of supporting the integrated wafer with an annular frame through a dicing tape.
6 is a perspective view showing a dividing process of dividing the integrated wafer into light emitting diode chips.
7 is a perspective view of the integrated wafer after the dividing process is completed.
8A to 8C are perspective views of a light emitting diode chip according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to Fig. 1, a perspective view on the front side of an optical device wafer (hereinafter, simply referred to as a wafer in some cases) 11 is shown.

The optical device wafer 11 is formed by laminating an epitaxial layer (laminate layer) 15 such as gallium nitride (GaN) on a sapphire substrate 13. The optical device wafer 11 has a surface 11a on which the epitaxial layer 15 is laminated, and a rear surface 11b on which the sapphire substrate 13 is exposed.

Here, in the optical device wafer 11 of this embodiment, the sapphire substrate 13 is employed as the substrate for crystal growth, but instead of the sapphire substrate 13, a GaN substrate or a SiC substrate may be employed.

The laminate layer (epitaxial layer) 15 includes an n-type semiconductor layer (e.g., an n-type GaN layer) in which electrons become a majority carrier, a semiconductor layer (e.g., an InGaN layer) serving as a light-emitting layer, and p It is formed by sequentially epitaxially growing a type semiconductor layer (for example, a p-type GaN layer).

The sapphire substrate 13 has a thickness of, for example, 100 µm, and the laminate layer 15 has a thickness of, for example, 5 µm. In the laminate layer 15, a plurality of LED circuits 19 are formed by being divided by a plurality of division scheduled lines 17 formed in a lattice shape. The wafer 11 has a front surface 11a on which the LED circuit 19 is formed and a rear surface 11b on which the sapphire substrate 13 is exposed.

According to the manufacturing method of the light emitting diode chip of the embodiment of the present invention, first, a wafer preparation step of preparing the optical device wafer 11 as shown in FIG. 1 is performed. Further, a transparent substrate processing step of forming a plurality of grooves corresponding to the LED circuit 19 on the surface 21a of the transparent substrate 21 adhered to the rear surface 11b of the wafer 11 is performed.

This transparent substrate processing step is performed using, for example, a well-known cutting device. 2A, the cutting unit 10 of the cutting device includes a spindle housing 12, a spindle (not shown) rotatably inserted in the spindle housing 12, and a front end of the spindle. It includes a mounted cutting blade (14).

The cutting edge of the cutting blade 14 is formed of, for example, an electric pole grindstone in which diamond abrasive grains are fixed by nickel plating, and the tip shape thereof has a triangular shape, a square shape, or a semicircle shape.

The substantially upper half of the cutting blade 14 is covered with a blade cover (wheel cover) 16, and the blade cover 16 has a pair (only one) extending horizontally to the depth side and the front side of the cutting blade 14. Figure) A cooler nozzle 18 is disposed.

In the transparent substrate processing step of forming a plurality of grooves 23 in the surface 21a of the transparent substrate 21, the transparent substrate 21 is suction-held by a chuck table of a cutting device (not shown). Then, while rotating the cutting blade 14 at a high speed in the direction of the arrow R, a predetermined depth is cut into the surface 21a of the transparent substrate 21, and the transparent substrate 21 held on a chuck table (not shown) is indicated by an arrow X1. By machining and feeding in the) direction, a groove 23 extending in the first direction is formed by cutting.

The surface 21a of the transparent substrate 21 is cut while indexing and transferring the transparent substrate 21 by the pitch of the line 17 to be divided of the wafer 11 in a direction orthogonal to the direction of the arrow X1, and FIG. 3 As shown in, a plurality of grooves 23 extending in the first direction are sequentially formed.

As shown in FIG. 3A, the plurality of grooves 23 formed on the surface 21a of the transparent substrate 21 may extend in only one direction, or as shown in FIG. 4. , A plurality of grooves 23 extending in the first direction and in a second direction orthogonal to the first direction may be formed in the surface 21a of the transparent substrate 21.

The groove formed on the surface 21a of the transparent substrate 21 is a groove 23 having a triangular cross-sectional shape as shown in (B) of FIG. 2, or a rectangular cross-sectional shape as shown in (C) of FIG. 2. Any one of the groove 23A of the shape or the groove 23B having a semicircular cross-sectional shape as shown in Fig. 2D may be used.

The transparent substrate 21 is formed of any one of transparent resin, optical glass, sapphire, and transparent ceramics. In this embodiment, the transparent substrate 21 was formed of a transparent resin such as polycarbonate and acrylic, which is more durable than optical glass. Further, as a method of forming the grooves, sand blasting, etching, or laser may be used.

After performing a transparent substrate processing step of forming a plurality of grooves 23, 23A, 23B on the surface 21a of the transparent substrate 21, the transparent substrate 21 is adhered to the back surface 11b of the wafer 11 An integration process of forming the integrated wafer 25 is performed.

In this integration step, as shown in Fig. 3A, the wafer 11 is formed on the surface of the transparent substrate 21 in which a plurality of grooves 23 extending in the first direction are formed on the surface 21a. The rear surface 11b is adhered with a transparent adhesive, and as shown in Fig. 3B, the wafer 11 and the transparent substrate 21 are integrated to form an integrated wafer 25.

As an alternative embodiment, the surface 21a of the transparent substrate 21 having a plurality of grooves 23 extending in a first direction and a second direction orthogonal to the first direction on the surface 21a of the transparent substrate 21 ), the back surface 11b of the wafer 11 may be adhered with a transparent adhesive, so that the wafer 11 and the transparent substrate 21 are integrated. Here, the pitch of the grooves 23 formed in the surface 21a of the transparent substrate 21 corresponds to the pitch of the line to be divided 17 of the wafer 11.

After performing the integration process, as shown in FIG. 5, the transparent substrate 21 of the integrated wafer 25 is attached to the dicing tape T with the outer circumference attached to the annular frame F to form a frame unit. , A support step of supporting the integrated wafer 25 with the annular frame F through the dicing tape T is performed.

After carrying out the supporting process, the frame unit is put into a cutting device, and the integrated wafer 25 is cut with the cutting device and divided into individual light emitting diode chips. This division step will be described with reference to FIG. 6.

In the dividing step, the integrated wafer 25 is sucked and held by the chuck table 20 of the cutting device through the dicing tape T of the frame unit, and the annular frame F is clamped and fixed with a clamp (not shown).

Then, while rotating the cutting blade 14 at high speed in the direction of the arrow R, it cuts into the line 17 to be divided of the wafer 11 until the tip of the cutting blade 14 touches the dicing tape T, The wafer 11 is scheduled to be divided by processing and transferring the integrated wafer 25 in the direction of the arrow X1 while supplying the cutting fluid from the cooler nozzle 18 toward the processing point of the cutting blade 14 and the wafer 11 A cutting groove 27 for cutting the wafer 11 and the transparent substrate 21 along the line 17 is formed.

While the cutting unit 10 is indexed and conveyed in the Y-axis direction, the same cutting grooves 27 are sequentially formed along the line to be divided 17 extending in the first direction. Subsequently, after rotating the chuck table 20 by 90°, the same cutting groove 27 is formed along all the division scheduled lines 17 extending in the second direction orthogonal to the first direction, as shown in FIG. 7. As a result, the integrated wafer 25 is divided into light emitting diode chips 31 as shown in Fig. 8A.

In the above-described embodiment, a cutting device is used to divide the integrated wafer 25 into individual light emitting diode chips 31, but a laser beam having a wavelength having transmittance to the wafer 11 and the transparent substrate 21 Is irradiated to the wafer 11 along the line 13 to be divided, to form a plurality of modified layers in the thickness direction inside the wafer 11 and the transparent substrate 21, and then to the integrated wafer 25. An external force may be applied to divide the integrated wafer 25 into individual light-emitting diode chips 31 with the modified layer as a division starting point.

In the light emitting diode chip 31 shown in Fig. 8A, a transparent member 21A is affixed to the rear surface of an LED 13A having an LED circuit 19 on its surface. Further, a groove 23 is formed on the surface of the transparent member 21A.

Therefore, in the light emitting diode chip 31 shown in Fig. 8A, since the groove 23 is formed on the surface of the transparent member 21A, the surface area of the transparent member 21A is increased. Further, a part of the light emitted from the LED circuit 19 of the light emitting diode chip 31 and incident on the transparent member 21A is refracted in the groove 23 and then enters into the transparent member 21A.

Accordingly, when the transparent member 21A is refracted to the outside and is emitted, the ratio of the light at which the incident angle at the interface between the transparent member 21A and the air layer becomes equal to or greater than the critical angle is reduced, and the amount of light emitted from the transparent member 21A This increases, and the luminance of the light emitting diode chip 31 is improved.

In the light emitting diode chip 31A shown in Fig. 8B, a transparent member 21A having a groove 23A having a rectangular cross-section on the surface is adhered to the rear surface of the LED 13A by a transparent adhesive. . In the light emitting diode chip 31A of the present embodiment, as in the light emitting diode chip 31 shown in Fig. 8A, a part of the light emitted from the LED circuit 19 and incident on the transparent member 21A is, After refracting in the portion of the groove 23A of the cross-sectional square, it enters into the transparent member 21A.

Accordingly, when the transparent member 21A is emitted from the inside to the outside, the ratio of the light at which the incident angle at the interface between the transparent member 21A and the air layer becomes equal to or greater than the critical angle decreases, and the amount of light emitted from the transparent member 21A decreases. Increases, and the luminance of the light emitting diode chip 31A is improved.

Referring to FIG. 8C, a perspective view of a light emitting diode chip 31B according to another embodiment is further shown. In the light emitting diode chip 31B of the present embodiment, since the grooves 23A having a rectangular cross-section are formed on the surface of the transparent member 21A in directions orthogonal to each other, they are emitted from the LED circuit 19 and are emitted from the transparent member ( Of the light incident on 21A), the amount of light that is refracted and incident in the groove 23A is increased.

Therefore, since the amount of light at which the incident angle at the interface between the transparent member 21A and the air layer becomes equal to or greater than the critical angle is reduced, the amount of light emitted from the transparent member 21A to the outside is increased, and thus the light emitting diode chip 31B is The luminance is improved.

In the embodiment shown in Figs. 8A to 8C, the transparent member 21A has a groove 23 having a triangular cross-section or a groove 23A having a rectangular cross-section, but the transparent member ( The same effect is also obtained when 21A) has the groove 23B having a semicircular cross-sectional shape shown in Fig. 2D.

10 cutting unit 11 optical device wafer (wafer)
13: sapphire substrate 14: cutting blade
15: laminate layer 17: line to be divided
19: LED circuit 21: transparent substrate
21A: transparent member 23, 23A, 23B: groove
25: integrated wafer 27: cut groove
31, 31A, 31B: light emitting diode chip

Claims (5)

As a method of manufacturing a light emitting diode chip,
On a first transparent substrate for crystal growth, a laminate layer including a plurality of semiconductor layers including a light emitting layer is formed on the surface thereof, and each LED in each region divided by a plurality of scheduled division lines crossing the surface of the laminate layer A wafer preparation step of preparing a wafer on which a circuit is formed, and
A transparent substrate processing process of forming a plurality of grooves having a predetermined depth corresponding to each LED circuit of the wafer on a surface of a second transparent substrate, wherein the plurality of grooves are formed in directions orthogonal to each other, and a pitch of the plurality of grooves Is corresponding to the pitch of the plurality of division scheduled lines, a transparent substrate processing process,
After performing the transparent substrate processing step, an integration step of forming an integrated wafer by adhering the surface of the second transparent substrate to the back surface of the wafer opposite to the surface of the wafer on which the laminate layer is formed;
Dividing process of dividing the integrated wafer into individual light emitting diode chips by cutting the wafer along with the second transparent substrate along the division scheduled line
Including,
The light emitting diode chip obtained by the dividing process includes a light emitting diode having an LED circuit formed on a surface thereof, and a transparent member that is the second transparent substrate adhered to the rear surface of the light emitting diode, and the light emitting diode of the transparent member is combined with the light emitting diode. A method of manufacturing a light emitting diode chip, wherein the plurality of grooves are formed in a direction orthogonal to each other on the adhesive surface. The method of claim 1, wherein the cross-sectional shape of the groove formed in the transparent substrate processing process is any one of a triangular shape, a square shape, and a semicircular shape. The method of claim 1, wherein in the transparent substrate processing process, the groove is formed by any one of a cutting blade, etching, sand blast, and laser. The method of claim 1, wherein the second transparent substrate is formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin, and in the integration process, the second transparent substrate is adhered to the wafer using a transparent adhesive. The method of manufacturing a light emitting diode chip. As a light emitting diode chip,
A light emitting diode having an LED circuit formed on a surface thereof, and a transparent member bonded to the back surface of the light emitting diode,
A light emitting diode chip wherein a plurality of grooves having a predetermined depth are formed in a direction orthogonal to each other on an adhesive surface of the transparent member with the light emitting diode.

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