KR102166197B1 - Method for manufacturing a light emitting diode chip and the light emitting diode chip - Google Patents

Abstract

(Task) To provide a method of manufacturing a light emitting diode chip and a light emitting diode chip in which sufficient luminance is obtained.
(Solution means) 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 a plurality of division scheduled lines intersecting 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 of the regions partitioned by the wafer, a wafer back surface processing step of forming a plurality of recesses or first grooves corresponding to each LED circuit on the back surface of the wafer, and a transparent substrate After performing the transparent substrate processing step of forming a plurality of second grooves corresponding to each LED circuit of the wafer on the back surface, the wafer back surface processing step, and the transparent substrate processing step, the surface of the transparent substrate on the back surface of the wafer And a dividing step of bonding the integrated wafer to form an integrated wafer, and a dividing step of dividing the integrated wafer into individual light emitting diode chips by cutting the wafer along with the transparent substrate along the line to be divided.

Description

Light emitting diode chip manufacturing method and light emitting diode chip {METHOD FOR MANUFACTURING A LIGHT EMITTING DIODE CHIP AND THE 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 crossing the laminate layer is formed. A wafer in which a plurality of light emitting devices such as LEDs (Light Emitting Diode) is formed in an area partitioned by a line is cut along the line to be divided and divided into individual light emitting device chips, and the divided light emitting device chips are mobile phones, PCs, and lighting It is widely used in various electric devices such as appliances.

Since the light emitted from the light emitting layer of the light emitting device chip has isotropic properties, it is irradiated to the inside of the substrate for crystal growth, and light is also emitted from the rear and side surfaces of the substrate. However, among the light irradiated to the inside of the substrate, light having an incident angle greater than or equal to the critical angle at the interface with the air layer is totally reflected at the interface and is trapped inside the substrate and is not emitted from the substrate to the outside, resulting in a decrease in the brightness of the light emitting device chip. There is.

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) in which a transparent member is attached to the back surface of the substrate to improve the luminance is provided. It is described in Japanese Unexamined Patent Application Publication No. 2014-175354.

Japanese Unexamined Patent Publication No. 2014-175354

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

The present invention has been made in view of such a point, and an object thereof is to provide a light emitting diode chip manufacturing method and a light emitting diode chip in which sufficient luminance can be obtained.

According to the invention according to 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 transparent substrate for crystal growth, and a plurality of divisions crossing each other on the surface of the laminate layer A wafer preparation step of preparing a wafer in which an LED circuit is formed in each area divided by a predetermined line; a wafer back surface processing step of forming a plurality of recesses or first grooves corresponding to each LED circuit on the back surface of the wafer; and , After performing the transparent substrate processing step of forming a plurality of second grooves corresponding to each LED circuit of the wafer on the back surface of the transparent substrate, the wafer back surface processing step, and the transparent substrate processing step, the wafer is placed on the back surface of the wafer. An integrated process of attaching the surface of a transparent substrate to form an integrated wafer, and a division process of cutting the wafer along with the transparent substrate along the line to be divided and dividing the integrated wafer into individual light emitting diode chips. A method of manufacturing a light emitting diode chip as characterized is provided.

Preferably, the cross-sectional shape of the second groove formed in the transparent substrate processing step is any of a triangular shape, a square shape, or a semicircular shape. Preferably, the concave portion or the first groove formed in the wafer back surface processing step is formed by any one of a cutting blade, etching, sand blast, and laser, and the second groove formed in the transparent substrate processing step is a cutting blade. It is formed by either etching, sandblasting, or laser.

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

According to the invention according to claim 5, a light emitting diode chip comprising: a light emitting diode having a concave portion or a first groove formed on a rear surface of which an LED circuit is formed on the surface, and a transparent member affixed to the rear surface of the light emitting diode, and the transparent member A light emitting diode chip in which a second groove is formed is provided on a surface opposite to the surface to which the light emitting diode is adhered.

In the light emitting diode chip of the present invention, since the second groove is formed on the back surface of the transparent member attached to the back 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 Since the concave portion or the first groove and the second groove portion are complicatedly refracted, the ratio of the light whose incident angle at the interface between the transparent member and the air layer is greater than or equal to the critical angle decreases when light exits from the transparent member. As the amount of emitted light increases, the brightness of the LED chip is improved.

1 is a front perspective view of an optical device wafer.
Fig. 2(A) is a perspective view showing a process of processing the back surface of a wafer using a cutting blade, and Figs. 2(B) to 2(D) are cross-sectional views showing a formed groove shape.
3(A) is a perspective view of the back side of a wafer having a plurality of grooves extending in a first direction formed on the back surface of the wafer, and FIG. 3(B) is a first direction formed on the back surface of the wafer and a first direction orthogonal to the first direction. It is a perspective view on the back side of a wafer in which a plurality of grooves extending in two directions are formed.
Fig. 4(A) is a perspective view showing a state in which a mask is attached to the back surface of a wafer, Fig. 4(B) is a perspective view showing a state in which a mask having a plurality of holes is attached to the back surface of the wafer, and Figs. 4(C) to Figs. 4(E) is a partial perspective view of the wafer showing the shape of the concave portion formed on the back surface of the wafer.
Fig. 5(A) is a perspective view showing a state in which grooves are formed on the back surface of a wafer by a laser beam, Fig. 5(B) is a partial cross-sectional view of a wafer showing a groove shape, and Fig. 5(C) is a view of the wafer by a laser beam. A perspective view showing a state in which a circular recess is formed on the back surface, and Fig. 5D is a partial perspective view of a wafer showing the formed circular recess.
Fig. 6(A) is a perspective view showing a process of processing a transparent substrate, and Figs. 6(B) to 6(D) are cross-sectional views showing a formed groove shape.
7(A) is a rear perspective view of a transparent substrate in which a plurality of grooves extending in a first direction are formed on the rear surface, and FIG. 7(B) is a rear perspective view of a transparent substrate in which a plurality of grooves crossing each other are formed on the rear surface.
Fig. 8(A) is a perspective view showing an integration process in which a transparent substrate having a plurality of grooves on the back surface is attached to the back surface of the wafer to be integrated, and Fig. 8(B) is a perspective view of the integrated wafer.
Fig. 9 is a perspective view showing a support step of supporting an integrated wafer with an annular frame via a dicing tape.
10 is a perspective view showing a dividing process for dividing the integrated wafer into light emitting diode chips.
11 is a perspective view of the integrated wafer after the dividing process is finished.
12(A) to 12(C) 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, sometimes abbreviated simply as a wafer) 11 is shown.

The optical device wafer 11 is configured 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 back surface 11b on which the sapphire substrate 13 is exposed.

Here, in the optical device wafer 11 of the present 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 laminated layer (epitaxial layer) 15 has an n-type semiconductor layer (e.g., an n-type GaN layer), a semiconductor layer (e.g., an InGaN layer) serving as a light emitting layer, and a number of holes. It is formed by sequentially epitaxially growing a p-type semiconductor layer (for example, a p-type GaN layer) serving as a carrier.

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 partitioned and formed by a plurality of planned division lines 17 formed in a grid shape. The wafer 11 has a 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 shown in FIG. 1 is performed. Further, a wafer back surface processing step of forming a plurality of grooves 3 corresponding to the LED circuit 19 on the back surface 11b of the wafer 11 is performed.

This wafer back surface processing step is performed using, for example, a well-known cutting device. As shown in Fig. 2(A), the cutting unit 10 of the cutting device includes a spindle housing 12, a spindle (not shown) rotatably inserted into the spindle housing 12, and mounted on the tip of the spindle. And a cutting blade (14).

The cutting blade of the cutting blade 14 is formed of, for example, an electroformed 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 semicircular shape.

The schematic upper half of the cutting blade 14 is covered with a blade cover (wheel cover) 16, and in the blade cover 16, only one pair (only one shown) extending horizontally to the inner and front sides of the cutting blade 14 ) The cooler nozzle 18 is arranged and formed.

In the wafer back surface processing step of forming a plurality of grooves 3 in the back surface 11b of the wafer 11, the surface 11a of the wafer 11 is suction-held by a chuck table of a cutting device (not shown). Then, while cutting the cutting blade 14 at a high speed in the direction of the arrow R, cutting a predetermined depth into the rear surface 11b of the wafer 11, and processing and transferring the wafer 11 held on the chuck table (not shown) in the direction of arrow X1 , A groove 3 extending in the first direction is formed by cutting.

The back surface 11b of the wafer 11 is cut while calculating and conveying the wafer 11 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 is shown in Fig. 3(A). As shown, a plurality of grooves 3 extending in the first direction are sequentially formed.

As shown in Fig. 3(A), the plurality of grooves 3 formed on the rear surface 11b of the wafer 11 may be extended only in one direction, or as shown in Fig. 3(B), A plurality of grooves 3 extending in one direction and a second direction orthogonal to the first direction may be formed in the rear surface 11b of the wafer 11.

The grooves formed on the rear surface 11b of the wafer 11 are the grooves 3 having a triangular cross-sectional shape shown in Fig. 2(B), or the groove 3A having a rectangular cross-sectional shape shown in Fig. 2(C), or Any of the cross-sectional semicircular grooves 3B shown in 2(D) may be used.

Instead of the embodiment in which a plurality of grooves 3, 3A, 3B are formed by cutting on the rear surface 11b of the wafer 11, a plurality of LED circuits 19 are provided on the rear surface 11b of the wafer 11 You may make it form the concave part of. In this embodiment, as shown in FIG. 4(A), a mask 2 having a plurality of holes 4 corresponding to the LED circuit 19 of the wafer 11 is used.

As shown in FIG. 4(B), the hole 4 of the mask 2 is made to correspond to each LED circuit 19 of the wafer 11, and the back surface 11b of the wafer 11 is attached|attached. Then, on the rear surface 11b of the wafer 11 by wet etching or plasma etching, as shown in Fig. 4(C), a triangular concave portion corresponding to the shape of the hole 4 of the mask 2 ( 5) to form.

By changing the shape of the hole 4 of the mask 2 to a square shape or a circular shape, a square-shaped concave portion 5A shown in Fig. 4(D) is formed on the back surface 11b of the wafer 11, or In addition, the circular concave portion 5B may be formed on the back surface 11b of the wafer 11 shown in FIG. 4E.

As a modified example of this embodiment, after attaching the mask 2 to the back surface 11b of the wafer 11, by performing sand blasting, the back surface 11b of the wafer 11 is shown in Fig. 4(C). The triangular concave part 5 shown in FIG., the rectangular concave part 5A shown in FIG. 4(D), or the circular concave part 5B shown in FIG. 4(E) may be formed.

A laser processing apparatus may be used to form a plurality of grooves or a plurality of recesses corresponding to the LED circuit 19 in the rear surface 11b of the wafer 11. In the first embodiment by laser processing, as shown in Fig. 5(A), a laser beam of a wavelength (e.g., 266 nm) having absorbency with respect to the wafer 11 is condensed (laser head) 24 While irradiating the back surface 11b of the wafer 11 from the wafer 11, the chuck table, not shown, holding the wafer 11 is processed and transferred in the direction of the arrow X1, thereby forming the groove 7 extending in the first direction into the wafer 11 It is formed by ablation on the back surface 11b of

The back surface 11b of the wafer 11 is ablation processed while the wafer 11 is computed and conveyed 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, in the first direction. A plurality of elongated grooves 7 are formed in sequence. The cross-sectional shape of the groove 7 may be, for example, a semicircular shape as shown in Fig. 5(B), or other shapes.

As an alternative embodiment, as shown in Fig. 5(C), a pulsed laser beam of a wavelength having absorption properties (e.g., 266 nm) is intermittently irradiated from the concentrator 24 to the wafer 11, 11) You may form a plurality of recesses 9 corresponding to the LED circuit 19 in the rear surface 11b. The shape of the concave portion 9 is usually a circular shape shown in Fig. 5(D) corresponding to the spot shape of the laser beam.

After or before carrying out the wafer back surface processing step, a plurality of grooves are formed corresponding to the LED circuit 19 on the back surface 21b of the transparent substrate 21 adhered to the back surface 11b of the wafer 11 A transparent substrate processing step is performed.

This transparent substrate processing step is performed using, for example, a well-known cutting device. In the transparent substrate processing step of forming a plurality of grooves 23 in the rear surface 21b 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 high speed in the direction of the arrow R, the transparent substrate 21 is cut to a predetermined depth in the rear surface 21b of the transparent substrate 21, and the transparent substrate 21 held on the chuck table (not shown) is processed in the direction of the arrow X1. By feeding, a groove 23 extending in the first direction is formed by cutting.

The back surface 21b of the transparent substrate 21 is cut while calculating and conveying 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, as shown in FIG. As described above, a plurality of grooves 23 extending in the first direction are sequentially formed.

As shown in Fig. 7(A), the plurality of grooves 23 formed on the rear surface 21b of the transparent substrate 21 may be extended only in one direction, or as shown in Fig. 7(B), A plurality of grooves 23 extending in the first direction and in the second direction orthogonal to the first direction may be formed in the rear surface 21b of the transparent substrate 21.

The groove formed in the rear surface 21b of the transparent substrate 21 is a groove 23 having a triangular cross-sectional shape shown in Fig. 6B, or a groove 23A having a rectangular cross-sectional shape shown in Fig. 6C, or Any of the grooves 23B having a semicircular cross section shown in Fig. 6D may be used.

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

After performing the transparent substrate processing step of forming a plurality of grooves 23, 23A, 23B on the rear surface 21b of the transparent substrate 21, the transparent substrate 21 is attached to the rear 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. 8(A), on the surface of the transparent substrate 21 in which a plurality of grooves 23 extending in the first direction are formed on the rear surface 21b, the rear surface of the wafer 11 ( 11b) is adhered with a transparent adhesive, and as shown in FIG. 8(B), the wafer 11 and the transparent substrate 21 are integrated to form an integrated wafer 25.

As an alternative embodiment, the rear surface 21b 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 rear surface 21b of the transparent substrate 21 ), the back surface 11b of the wafer 11 may be bonded to each other with a transparent adhesive, as shown in Fig. 8A, so that the wafer 11 and the transparent substrate 21 are integrated. Here, the pitch of the grooves 23 formed in the rear surface 21b of the transparent substrate 21 corresponds to the pitch of the line to be divided 17 of the wafer 11.

After performing the integration step, as shown in FIG. 9, the transparent substrate 21 of the integrated wafer 25 is adhered to the dicing tape T with the outer peripheral portion 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 via the dicing tape T is performed.

After performing the supporting step, the frame unit is put into a cutting device, and the integrated wafer 25 is cut with the cutting device, and a dividing step of dividing it into individual light emitting diode chips is performed. This division step will be described with reference to FIG. 10.

In the dividing step, the integrated wafer 25 is sucked and held by the chuck table 20 of the cutting device via 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, and the cooler nozzle The integrated wafer 25 is processed and transported in the direction of the arrow X1 while supplying the cutting fluid from 18 to the processing point of the cutting blade 14 and the wafer 11, whereby the line 17 to be divided of the wafer 11 Along the same, cut grooves 27 for cutting the wafer 11 and the transparent substrate 21 are formed.

While calculating and conveying the cutting unit 10 in the Y-axis direction, the same cutting grooves 27 are sequentially formed along the division scheduled line 17 extending in the first direction. Next, after rotating the chuck table 20 by 90°, the same cut grooves 27 are formed along all the division scheduled lines 17 extending in the second direction orthogonal to the first direction, and the state shown in FIG. 11 By setting it as, the integrated wafer 25 is divided into light emitting diode chips 31 shown in Fig. 12A.

In the above-described embodiment, a cutting device is used to divide the integrated wafer 25 into individual light emitting diode chips 31, but the wavelength having transmittance to the wafer 11 and the transparent substrate 21 A laser beam is irradiated to the wafer 11 along the line to be divided 13 to form a plurality of modified layers in the thickness direction inside the wafer 11 and the transparent substrate 21, and then, the integrated wafer 25 ) May be applied to an external force 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. 12A, a transparent member 21A is affixed to the rear surface of an LED 13A having an LED circuit 19 on the surface. Further, the concave portion 5 or the groove 3 is formed in the rear surface 11b of the wafer 11, and the groove 23 is formed in the rear surface of the transparent member 21A.

Therefore, in the light emitting diode chip 31 shown in Fig. 12A, since the groove 23 is formed on the back surface of the transparent member 21A, the surface area of the transparent member 21A is increased. In addition, 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 a concave portion 5 or a groove 3 formed in the back surface 11b of the wafer 11 ), after being refracted at the portion of the groove 23 formed on the rear surface of the transparent member 21A, it enters 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 decreases, and the amount of light emitted from the transparent member 21A decreases. Increases, and the brightness of the light emitting diode chip 31 is improved.

In the light emitting diode chip 31A shown in FIG. 12B, in addition to the recess 5 or the groove 3 formed on the rear surface of the LED 13A, the LED 13A has a rectangular cross-sectional shape on the rear surface. The transparent member 21A having the groove 23A is adhered with 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. 12A, a part of the light emitted from the LED circuit 19 and incident on the transparent member 21A is an LED After refracting in the concave portion 5 or groove 3 formed on the rear surface of 13A and the groove 23A formed on the rear surface of the transparent member 21A, it enters the transparent member 21A.

Therefore, when emitted from the transparent member 21A 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 increases. Then, the luminance of the light emitting diode chip 31A is improved.

Referring to Fig. 12C, a perspective view of a light emitting diode chip 31B according to another embodiment is shown. In the light emitting diode chip 31B of this embodiment, the recessed portion 5 or the groove 3 is formed on the rear surface of the LED 13A, and the groove 23B having a semicircular cross-section on the rear surface of the transparent member 21A. ) Are formed in directions orthogonal to each other.

In the light emitting diode chip 31B of the present embodiment, since the groove 23B having a semicircular cross-section is formed on the rear surface of the transparent member 21A in a direction orthogonal to each other, it is emitted from the LED circuit 19 and is emitted from the transparent member ( A part of the light entering 21A) is complexly refracted in the groove 23B and is emitted to the outside.

Therefore, when light is emitted from the transparent member 21A to the outside, 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 decreases, the amount of light emitted from the transparent member 21A to the outside is reduced. The amount of light increases, and the brightness of the light emitting diode chip 31B is improved.

2: mask
3, 3A, 3B: groove
4: hole
5, 5A, 5B: recess
7: home
9: recess
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: cutting groove
31, 31A, 31B: light emitting diode chip

Claims (5)

As a method of manufacturing a light emitting diode chip,
A wafer having 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 in which an LED circuit is formed in each region divided by a plurality of scheduled division lines intersecting the surface of the laminate layer. The wafer preparation process to be prepared,
A wafer back surface processing step of forming a plurality of recesses or first grooves corresponding to each LED circuit on the back surface of the wafer; and
A transparent substrate processing step of forming a plurality of second grooves corresponding to each LED circuit of the wafer on the rear surface of the transparent substrate,
After performing the wafer back surface processing step and the transparent substrate processing step, an integration step of attaching the surface of the transparent substrate to the back surface of the wafer to form an integrated wafer, and
A method of manufacturing a light emitting diode chip, comprising: a dividing step of cutting the wafer along with the transparent substrate along the line to be divided and dividing the integrated wafer into individual light emitting diode chips. The method of claim 1,
A method of manufacturing a light emitting diode chip in which the cross-sectional shape of the second groove formed in the transparent substrate processing step is any of a triangular shape, a square shape, and a semicircular shape. The method of claim 1,
In the wafer back surface processing step, the concave portion or the first groove is formed by any one of a cutting blade, etching, sand blast, and laser,
In the transparent substrate processing step, the second groove is formed of a cutting blade, etching, sand blast, or laser. The method of claim 1,
The transparent substrate is formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin, and in the integration step, the transparent substrate is affixed to the wafer using a transparent adhesive. As a light emitting diode chip,
A light emitting diode having an LED circuit formed on the surface and a concave portion or a first groove formed on the rear surface thereof;
A transparent member adhered to the back surface of the light emitting diode is provided,
A light emitting diode chip in which a second groove is formed on a surface of the transparent member on the opposite side of the surface to which the light emitting diode is adhered.

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