TWI771358B - Manufacturing method of light-emitting diode chip and light-emitting diode chip - Google Patents

Abstract

[Subject] To provide a method for producing a light emitting diode wafer and a light emitting diode wafer capable of obtaining sufficient brightness. [Solution] A method of manufacturing a light-emitting diode wafer, comprising: a wafer preparation step of preparing a wafer having a laminate layer on a transparent substrate for crystal growth, and the laminate layer is LED circuits are formed in each area demarcated by a plurality of predetermined dividing lines crossing each other on the front surface of the LED, and a plurality of semiconductor layers including a light-emitting layer are formed on the laminated body layer; the first transparent substrate attaching step is to attach the first transparent substrate. The front side of the substrate is attached to the back side of the wafer to form a first integrated wafer; the second transparent substrate attaching step, after the first transparent substrate attaching step has been performed, the front side of the second transparent substrate is attached to the the backside of the first transparent substrate to form a second integrated wafer, wherein a plurality of air bubbles are formed in the second transparent substrate; and a dividing step, the wafer and the first and second The transparent substrate is cut together to divide the second integrated wafer into individual light-emitting diode wafers.

Description

Manufacturing method of light-emitting diode chip and light-emitting diode chip Field of Invention

The present invention relates to a manufacturing method of a light-emitting diode wafer and the light-emitting diode wafer.

Background of the Invention

On the front surface of a substrate for crystal growth such as a sapphire substrate, a GaN substrate, and a SiC substrate, a laminate layer formed by laminating a plurality of layers of an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer is formed. A wafer in which a plurality of light-emitting elements such as LEDs (Light Emitting Diodes) are formed in an area demarcated by a plurality of intersecting planned dividing lines is cut along the planned dividing lines and divided into individual pieces. The divided light-emitting element wafers can be widely used in various electrical equipment such as mobile phones, personal computers, and lighting equipment.

Since the light emitted from the light emitting layer of the light emitting element wafer is isotropic, even if it is irradiated into the inside of the substrate for crystal growth, the light is emitted from the back surface and the side surface of the substrate. However, among the light irradiated inside the substrate, light whose incident angle on the interface with the air layer is greater than or equal to the critical angle is totally reflected at the interface and enclosed inside the substrate, and there is no When it is emitted from the substrate to the outside, there is a problem that the brightness of the light-emitting element wafer is lowered.

In order to solve this problem, Japanese Patent Laid-Open No. 2014-175354 discloses a light emitting diode (LED) which is formed on the substrate in order to prevent the light emitted from the light emitting layer from being trapped inside the substrate. A transparent member is attached to the back to improve the brightness.

prior art literature Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2014-175354

Summary of Invention

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

The present invention has been made in view of such a point, and an object of the present invention is to provide a method for producing a light-emitting diode wafer and a light-emitting diode wafer capable of obtaining sufficient brightness.

According to the invention described in claim 1, there can be provided a method of manufacturing a light-emitting diode chip, the method of manufacturing a light-emitting diode chip comprising: a wafer preparation step of preparing a wafer, the wafer being crystallized The transparent substrate for growth has a laminated body layer, and the front surface of the laminated body layer is mutually LED circuits are respectively formed in each area demarcated by a plurality of intersecting predetermined dividing lines, and a plurality of semiconductor layers including a light-emitting layer are formed on the laminated body layer; the first transparent substrate attaching step is to attach the front surface of the first transparent substrate. attached to the back of the wafer to form a first integrated wafer; a second transparent substrate attaching step, after the first transparent substrate attaching step has been performed, attaching the front surface of the second transparent substrate to the first transparent substrate the back surface to form a second integrated wafer, wherein the second transparent substrate has a plurality of air bubbles formed therein; and a dividing step, cutting the wafer together with the first and second transparent substrates along the planned dividing line The second integrated wafer is divided into individual light-emitting diode chips.

Preferably, the first and second transparent substrates are formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin, and the first and second transparent substrate attaching steps are performed using a transparent adhesive. implement.

According to the invention described in claim 4, a light-emitting diode chip can be provided, the light-emitting diode chip is characterized by comprising: a light-emitting diode having an LED circuit formed on the front surface; The 1st transparent member of the back surface of a body, and the 2nd transparent member which attached the front surface to the back surface of this 1st transparent member, and has a some bubble inside.

Since the light-emitting diode chip of the present invention attaches the front surface of the first transparent member to the back surface of the LED, and will have a plurality of gas inside The front surface of the second transparent member of the bubble is attached to the back surface of the first transparent member, so the light is refracted in a complicated manner in the first and second transparent members, and the light enclosed in the first and second transparent members is reduced. , and the amount of light emitted from the first and second transparent members is increased to improve the brightness of the light-emitting diode chip.

10: Cutting unit

11: Optical element wafer (wafer)

11a, 21a: Front

11b: Back

12: Spindle housing

13: Sapphire substrate

13A: LED

14: Cutter

15: Laminated body layer (crystal film layer)

16: Blade cover

17: Divide the scheduled line

18: Cooling Nozzles

19: LED circuit

20: Work clamp table

21: The first transparent substrate

21A: Second transparent substrate

21': 1st transparent member

21A': 2nd transparent member

25: 1st integrated wafer

25A: 2nd integrated wafer

27: Cut off the ditch

29: Bubbles

31: LED chip

R, X1: arrow

T: cutting tape

F: Ring frame

X, Y, Z: direction

FIG. 1 is a front perspective view of an optical element wafer.

FIG. 2(A) is a perspective view showing a first transparent substrate attaching step in which the front surface of the first transparent substrate is attached to the back surface of the wafer for integration, and FIG. 2(B) is a perspective view of the first integrated wafer .

3(A) is a perspective view showing a second transparent substrate attaching step of integrating the front surface of the second transparent substrate to the back surface of the first transparent substrate of the first integrated wafer, and FIG. 3(B) It is a perspective view of the second integrated wafer.

4 is a perspective view showing a supporting step of supporting the second integrated wafer by the annular frame through the dicing tape.

FIG. 5 is a perspective view showing a dividing step of dividing the second integrated wafer into light-emitting diode wafers.

FIG. 6 is a perspective view of the second integrated wafer after the dividing step is completed.

7 is a perspective view of a light-emitting diode wafer according to an embodiment of the present invention.

Form for carrying out the invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1 , there is shown a front perspective view of an optical element wafer (hereinafter, sometimes simply referred to as a wafer) 11 .

The optical element wafer 11 is formed by depositing nitrogen on the sapphire substrate 13 An epitaxial layer (laminate layer) 15 of gallium nitride (GaN) or the like is formed. The optical element wafer 11 has a front surface 11 a on which the die film layer 15 is laminated, and a back surface 11 b on which the sapphire substrate 13 is exposed.

Here, in the optical element wafer 11 of the present embodiment, although the sapphire substrate 13 is used as the substrate for crystal growth, a GaN substrate, a SiC substrate, or the like may be used instead of the sapphire substrate 13 .

The laminated body layer (crystal film layer) 15 is formed by an n-type semiconductor layer (for example, an n-type GaN layer) in which electrons become a majority carrier, a semiconductor layer (for example, an InGaN layer) serving as a light-emitting layer, and a majority of holes in this order. A p-type semiconductor layer (eg, a p-type GaN layer) of carriers is formed by crystal film growth.

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. A plurality of LED circuits 19 are formed on the laminate layer 15 by dividing by a plurality of planned division lines 17 formed in a lattice shape. The wafer 11 has a front surface 11 a on which the LED circuit 19 is formed, and a back surface 11 b on which the sapphire substrate 13 is exposed.

According to the manufacturing method of the light emitting diode wafer according to the embodiment of the present invention, a wafer preparation step of preparing the optical element wafer 11 as shown in FIG. 1 is first performed. In addition, the transparent substrate preparation step of preparing the first and second transparent substrates is also carried out.

After the transparent substrate preparation step is performed, a first transparent substrate attaching step is performed, which is to attach the front surface 21 a of the first transparent substrate 21 to the wafer 11 as shown in FIG. 2(A) . Backside 11b. FIG. 2(B) is a perspective view of the first integrated wafer 25 .

The first transparent substrate 21 is made of transparent resin, optical glass, Any of sapphire and transparent ceramics. In the present embodiment, the first and second transparent substrates are formed of transparent resins such as polycarbonate and acrylic resin which are more durable than optical glass.

After the first transparent substrate attaching step has been performed, as shown in FIG. 1. The back surface of the transparent substrate 21 (second transparent substrate attaching step) to form the second integrated wafer 25A as shown in FIG. 3(B) . The material of the second transparent substrate 21A is also the same as the material of the first transparent substrate 21 described above.

Instead of the first transparent substrate attaching step and the second transparent substrate attaching step described above, the front surface of the second transparent substrate 21A is attached to the back surface of the first transparent substrate 21 to form an integration, and then the The back surface 11 b of the wafer 11 may be attached to the front surface 21 a of the first transparent substrate 21 .

After the second transparent substrate attaching step has been performed, a supporting step is performed. As shown in FIG. 4 , the second transparent substrate 21A of the second integrated wafer 25A is attached to the outer peripheral portion and attached to the ring shape. The dicing tape T on the frame F forms a frame unit, and the second integrated wafer 25A is supported by the annular frame F through the dicing tape T.

After the supporting step has been performed, a dividing step is performed in which the frame unit is put into a cutting device and the second integrated wafer 25A is cut by the cutting device to be divided into individual light emitting diode wafers. This dividing step will be described with reference to FIG. 5 .

This dividing step is carried out using, for example, a well-known cutting device. As shown in FIG. 5, the cutting unit 10 of the cutting device includes The spindle housing 12, a spindle (not shown) that is rotatably inserted into the spindle housing 12, and a cutting tool 14 attached to the front end of the spindle.

The cutting edge of the cutting blade 14 is formed of, for example, an electroforming grindstone in which diamond abrasive grains are fixed by nickel plating, and the tip shape thereof is triangular, quadrangular, or semicircular.

A substantially upper half of the cutting blade 14 is covered by a blade cover (wheel cover) 16, and the blade cover 16 is provided with a horizontally extending portion on the back side and the front side of the cutting blade 14. Pair (only one is shown in the figure) cooling nozzle 18.

In the dividing step, the second integrated wafer 25A is sucked and held on the table 20 of the cutting apparatus through the dicing tape T of the frame unit, and the ring-shaped frame F is clamped and fixed by a jig not shown. .

Then, the cutting blade 14 is rotated at a high speed in the direction of the arrow R while cutting into the line 17 to be divided into the wafer 11 until the tip of the cutting blade 14 reaches the dicing tape T, and from the cooling nozzle 18 toward the cutting blade 14 and the wafer 11 The second integrated wafer 25A is processed and fed in the direction of arrow X1 while the cutting fluid is supplied at the processing point, thereby forming the cutting wafer 11 and the first and second transparent substrates 21 and The cutting groove 27 of 21A.

The cutting unit 10 is indexed and fed in the Y-axis direction, and the same cutting grooves 27 are sequentially formed along the planned dividing line 17 extending in the first direction. Next, after the table 20 is rotated by 90°, the same cutting grooves 27 are formed along all the planned dividing lines 17 extending in the second direction orthogonal to the first direction to form the state shown in FIG. 6 . , thereby integrating the second The wafer 25A is divided into light emitting diode chips 31 as shown in FIG. 7 .

In the above-mentioned embodiment, although the cutting device is used for the light-emitting diode wafers 31 for dividing the second integrated wafer 25A into individual pieces, it may be arranged such that the wafer 11 and the transparent substrate 21, 21A is irradiated to the wafer 11 along the planned dividing line 17 with a laser beam having a penetrating wavelength, and a plurality of layers are formed in the thickness direction of the wafer 11 and the inside of the first transparent substrate 21 and the second transparent substrate 21A. Next, an external force is applied to the second integrated wafer 25A to divide the second integrated wafer 25A into individual light-emitting diode chips 31 using the modified layer as a starting point for division.

In the light-emitting diode chip 31 shown in FIG. 7, a first transparent member 21' is attached to the back surface of the LED 13A having the LED circuit 19 on the front surface. In addition, a second transparent member 21A' having a plurality of air cells 29 inside is attached to the back surface of the first transparent member 21'.

Therefore, in the light-emitting diode wafer 31 shown in FIG. 7 , in addition to increasing the surface areas of the first and second transparent members 21 ′ and 21A′, light is also allowed to pass through the first and second transparent members 21 ′. 21A' is refracted in a complex manner, so that the light enclosed in the transparent member is reduced, the amount of light emitted from the transparent members 21', 21A' is increased, and the brightness of the light-emitting diode chip 31 is improved.

11‧‧‧Optical component wafer (wafer)

11a, 21a‧‧‧Front

21‧‧‧First transparent substrate

21A‧‧‧Second transparent substrate

25‧‧‧First integrated wafer

25A‧‧‧Second integrated wafer

29‧‧‧Bubble

Claims (4)

A method for manufacturing a light-emitting diode chip, the method for manufacturing a light-emitting diode chip is characterized by comprising: a wafer preparation step of preparing a wafer having a laminate layer on a transparent substrate for crystal growth, LED circuits are respectively formed in each area demarcated by a plurality of predetermined dividing lines crossing each other on the front surface of the laminated body layer, and the laminated body layer is formed with a plurality of semiconductor layers including a light-emitting layer; the first transparent substrate attaching step , the front side of the first transparent substrate is attached to the back side of the wafer to form a first integrated wafer, and the first transparent substrate has no air bubbles formed inside; the second transparent substrate attaching step has already implemented the first transparent substrate After the substrate attaching step, the front surface of the second transparent substrate is attached to the back surface of the first transparent substrate to form a second integrated wafer, and the second transparent substrate is formed with a plurality of air bubbles inside; and the dividing step is performed along the The wafer and the first and second transparent substrates are cut along the planned dividing line to divide the second integrated wafer into individual light-emitting diode chips. The method for manufacturing a light-emitting diode chip as claimed in claim 1, wherein instead of the first transparent substrate attaching step and the second transparent substrate attaching step, the front surface of the second transparent substrate is attached to the After the back surface of the first transparent substrate is integrated, the back surface of the wafer is attached to the front surface of the first transparent substrate. The manufacturer of the light-emitting diode chip as claimed in claim 1 method, wherein the first and second transparent substrates are formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin, and the first and second transparent substrate attaching steps are performed using a transparent adhesive . A light-emitting diode chip, the light-emitting diode chip is characterized by comprising: a light-emitting diode, an LED circuit is formed on the front surface; a first transparent member, the front surface is attached to the back of the light-emitting diode, and No air bubbles are formed inside; and the second transparent member has a front surface attached to the back surface of the first transparent member and has a plurality of air bubbles inside.

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