TW201837999A - Manufacturing method of light-emitting diode chip and light-emitting diode chip to obtain a sufficient luminance - Google Patents

Abstract

To provide a manufacturing method of light-emitting diode chip and light-emitting diode chip which can obtain a sufficient luminance. The manufacturing method of a light-emitting diode chip comprises the steps of: a wafer preparing step to prepare a wafer, the wafer having a laminated body on a transparent substrate for crystal growth, the front surface of the laminated layer having LED circuits respectively formed in each region divided by plural mutually intersected and predetermined division lines, a plurality of semiconductor layers including a light-emitting layer being formed in the laminated layer; a transparent substrate processing step of forming a plurality of recesses corresponding to each LED circuit on the front surface or back surface of at least one of the first transparent substrate or the second transparent substrate; a transparent substrate adhering step, after performing the step of processing the transparent substrate, adhering the front surface of the first transparent substrate to the back surface of the wafer, and adhering the front surface of the second transparent substrate to the back surface of the first transparent substrate to form an integrated wafer; and a dividing step, after performing the transparent substrate adhering step, cutting the wafer together with the first and second transparent substrates along the predetermined division lines to divide the integrated wafer into individual light-emitting diode chips.

Description

Manufacturing method of light emitting diode wafer and light emitting diode wafer

FIELD OF THE INVENTION The present invention relates to a method for manufacturing a light emitting diode wafer and a 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 multilayer body layer formed by laminating a plurality of n-type semiconductor layers, light-emitting layers, and p-type semiconductor layers is formed, and on the multilayer body layers A wafer in which a plurality of light emitting elements such as LEDs (Light Emitting Diodes) are formed in an area defined by a plurality of intersecting division lines is cut along the division line and divided into The light-emitting element wafers one by one, and the divided light-emitting element wafers can be widely used in various electric devices 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 to the inside of the substrate for crystal growth, the light is emitted from the back and sides of the substrate. However, since the light that has been irradiated to the inside of the substrate has an incident angle above the critical angle at the interface with the air layer, the light is totally reflected on the interface and is enclosed inside the substrate. Since it is emitted from the substrate to the outside, there is a problem that the brightness of the light emitting element wafer is reduced.

In order to solve this problem, Japanese Patent Laid-Open No. 2014-175354 has described a light-emitting diode (LED) that is formed on the substrate in order to prevent the light emitted from the light-emitting layer from being enclosed inside the substrate. A transparent member is attached to the back of the lens to increase brightness. Prior Art Literature Patent Literature

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

SUMMARY OF THE INVENTION Problems to be Solved by the 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 points, and an object thereof is to provide a method for manufacturing a light emitting diode wafer and a light emitting diode wafer capable of obtaining sufficient brightness. Means to solve the problem

According to the invention described in claim 1, a method for manufacturing a light emitting diode wafer can be provided. The method for manufacturing a light emitting diode wafer includes: a wafer preparation step, preparing a wafer, and the wafer is crystallized A growth substrate has a laminated body layer, and an LED circuit is formed in each of the areas defined by a plurality of predetermined division lines crossing each other on the front side of the laminated body layer. The laminated body layer is formed with a plurality of layers including a light emitting layer. A semiconductor layer; a transparent substrate processing step, forming a plurality of depressions corresponding to each LED circuit on the front or back of at least one of the first transparent substrate or the second transparent substrate; the transparent substrate attaching step, in which the transparent substrate is implemented After the processing step, attaching the front surface of the first transparent substrate to the back of the wafer, and attaching the front surface of the second transparent substrate to the back of the first transparent substrate to form an integrated wafer; and a dividing step, After the transparent substrate attaching step is performed, the wafer is cut along with the first and second transparent substrates along the predetermined dividing line to form the integrated crystal. A light emitting diode is divided into a number of wafer.

Preferably, the cross-sectional shape of the depression formed in the transparent substrate processing step is any one of a triangle, a quadrangle, or a circle. Preferably, the depressions formed in the transparent substrate processing step are formed by any one of etching, sandblasting, and laser.

Preferably, the first and second transparent substrates are formed of any one of transparent ceramic, optical glass, sapphire, and transparent resin, and in the transparent substrate attaching step, the first transparent substrate is made of a transparent adhesive. The second transparent substrate is adhered to the wafer, and is adhered to the first transparent substrate by a transparent adhesive.

According to the invention described in claim 5, it is possible to provide a light-emitting diode wafer including a light-emitting diode in which an LED circuit is formed on a front surface, and a first transparent layer attached to a back surface of the light-emitting diode. A member and a second transparent member adhered to the back surface of the first transparent member, and a depression is formed on the front surface or the back surface of at least one of the first transparent member or the second transparent member. Invention effect

Since the light-emitting diode wafer of the present invention has recesses formed on the front surface or the back surface of at least one of the first transparent member or the second transparent member, the surface area of the first transparent member or the second transparent member is increased. In addition, at least two layers of transparent members and recesses can be used to refract light intricately, reduce the light enclosed in the first and second transparent members, and allow light emitted from the first and second transparent members to be reduced. The amount is increased and the brightness of the light emitting diode wafer is increased.

Embodiments for Carrying Out the Invention Embodiments of the present invention will be described in detail below with reference to the drawings. Referring to FIG. 1, a front perspective view of an optical element wafer (hereinafter sometimes referred to as a wafer) 11 is shown.

The optical element wafer 11 is formed by laminating an epitaxial layer (laminated body layer) 15 such as gallium nitride (GaN) on the sapphire substrate 13. The optical element wafer 11 includes a front surface 11 a on which the crystal film layer 15 is laminated, and a back surface 11 b on which the sapphire substrate 13 is exposed.

Here, although the sapphire substrate 13 is used as the substrate for crystal growth in the optical element wafer 11 of this embodiment, 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 an n-type semiconductor layer (for example, an n-type GaN layer), a semiconductor layer (for example, an InGaN layer) that becomes a light-emitting layer, and holes are formed by sequentially making electrons a majority carrier. A carrier p-type semiconductor layer (for example, a p-type GaN layer) is formed by crystal film growth.

The sapphire substrate 13 has a thickness of, for example, 100 μm, and the laminated body layer 15 has a thickness of, for example, 5 μm. The laminated body layer 15 is divided into a plurality of predetermined division lines 17 formed in a grid pattern to form a plurality of LED circuits 19. The wafer 11 includes 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 method for manufacturing a light-emitting diode wafer according to the embodiment of the present invention, first, a wafer preparation step of preparing an optical element wafer 11 as shown in FIG. 1 is performed. Then, a transparent substrate processing step is performed, which is performed on the front or back surface of the first transparent substrate to be attached to the back surface 11b of the wafer 11, or on the second surface of the first transparent substrate to be attached. A plurality of depressions are formed on the front or back of the transparent substrate corresponding to the LED circuit 19.

In this transparent substrate processing step, for example, as shown in FIG. 2 (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. 2 (B), the hole 4 of the mask 2 is made to correspond to each LED circuit 19 of the wafer 11, and the mask is attached to the front surface 21 a of the first transparent substrate 21.

Then, as shown in FIG. 2 (C), a triangular shape corresponding to the shape of the hole 4 of the mask 2 is formed on the front surface 21a of the first transparent substrate 21 by wet etching or plasma etching. Depression (recess) 5.

It can also be set to change the shape of the hole 4 of the mask 2 into a quadrangle or a circle, and form a quadrangular depression 5A as shown in FIG. 2 (D) on the front surface 21a of the first transparent substrate 21, or As shown in FIG. 2 (E), a circular depression 5B is formed on the front surface 21 a of the first transparent substrate 21.

The first transparent substrate 21 is formed of any one of transparent resin, optical glass, sapphire, and transparent ceramic. In this embodiment, the first transparent substrate 21 is formed of a transparent resin such as polycarbonate or acrylic which is more durable than optical glass.

As a modification of this embodiment, it is also possible to form the front surface 21a of the first transparent substrate 21 as shown in FIG. 2 by attaching the mask 2 to the front surface 21a of the first transparent substrate 21 and then performing sandblasting. A triangular depression 5 shown in (C), or a quadrangular depression 5A shown in FIG. 2 (D), or a circular depression 5B shown in FIG. 2 (E).

It is also possible to use a laser processing device in which a plurality of depressions corresponding to the LED circuit 19 are formed on the front surface 21 a of the first transparent substrate 21. In the embodiment performed by laser processing, as shown in FIG. 3 (A), the laser beam having a wavelength (for example, 266 nm) having an absorptivity to the first transparent substrate 21 is intermittently removed from the condenser (Laser head) 24 irradiates the front surface 21a of the first transparent substrate 21, and feeds a work clamp (not shown) holding the first transparent substrate 21 in the direction of arrow X1, thereby ablating (ablation) ) A plurality of depressions 9 corresponding to the LED circuits 19 of the wafer 11 are formed on the front surface 21 a of the first transparent substrate 21.

The first transparent substrate 21 is fed in the direction orthogonal to the direction of the arrow X1 at each pitch of the planned division line 17 of the wafer 11, and the front surface 21a of the first transparent substrate 21 is subjected to ablation processing to A plurality of depressions 9 are successively formed. The cross-sectional shape of the depression 9 is generally a circle as shown in FIG. 3 (B) corresponding to the spot shape of the laser beam.

Although the plurality of depressions 5, 5A, 5B, and 9 are formed on the front surface 21a of the first transparent substrate 21 in the above-mentioned transparent substrate processing step, the first transparent substrate 21 may be replaced by this embodiment. A plurality of recesses 5, 5A, 5B, and 9 are formed on the back surface 21b of the substrate.

Alternatively, it is also possible to provide a plurality of depressions 5 on the front surface 21 and the back surface of the first transparent substrate 21 without performing any processing, but on the front surface 21a or the back surface 21b of the second transparent substrate 21A corresponding to the LED circuits of the wafer 11 , 5A, 5B, 9. Similarly to the first transparent substrate 21, the second transparent substrate 21A is formed of any one of transparent resin, optical glass, sapphire, and transparent ceramic.

After the transparent substrate processing step has been performed, a transparent substrate attaching step is performed in which the front surface 21a of the first transparent substrate 21 is attached to the back surface 11b of the wafer 11 and the front surface of the second transparent substrate 21A is attached. 21a is attached to the back surface 21b of the first transparent substrate 21.

In this transparent substrate attaching step, first, as shown in FIG. 4 (A), the back surface 11b of the wafer 11 is adhered to the LED circuit 19 corresponding to the wafer 11 on the front surface 21a by a transparent adhesive. The front surface 21 a of the first transparent substrate 21 having the plurality of depressions 9 is integrated with the first transparent substrate 21 to form a first integrated wafer 25 as shown in FIG. 4 (B).

Next, as shown in FIG. 5 (A), the front surface 21a of the second transparent substrate 21A is attached to the back surface 21b of the first transparent substrate 21 of the first integrated wafer 25 to form a surface as shown in FIG. 5 (B). The second integrated wafer 25A.

This transparent substrate attaching step is not limited to the above-mentioned steps, and it may be set as follows: After the front surface 21a of the second transparent substrate 21A is attached to the back surface 21b of the first transparent substrate 21, the first transparent substrate 21 is attached. The front surface 21a is attached to the back surface 11b of the wafer 11 to form a second integrated wafer 25A.

After the transparent substrate attaching step has been performed, a supporting step is performed. As shown in FIG. 6, the second transparent substrate 21A of the second integrated wafer 25A is attached to the outer peripheral portion and attached to the ring frame F. The dicing tape T is used to form a frame unit, and the second integrated wafer 25A is supported by the cyclic frame F through the dicing tape T.

After the supporting step has been performed, a slicing step is performed. The slicing step is to put the frame unit into a cutting device, and use the cutting device to cut the second integrated wafer 25 to be divided into individual light-emitting diode wafers. This division step will be described with reference to FIG. 7.

As shown in FIG. 7, the cutting unit 10 of the cutting apparatus includes a main shaft housing 12, a main shaft (not shown) rotatably inserted into the main shaft housing 12, and a cutting blade 14 installed at a front end of the main shaft.

The cutting edge of the cutting blade 14 is formed by, for example, an electroformed grindstone in which diamond abrasive grains are fixed by nickel plating, and the front end shape is made into a triangle, a quadrangle, or a semicircle.

Approximately the upper half of the cutting blade 14 is covered by a blade cover (wheel cover) 16. The blade cover 16 is provided with a horizontally elongated one on the inner side and near the front side of the cutting blade 14. Pairs (only one is shown) of cooling nozzles 18.

In the dividing step, the second integrated wafer 25A is sucked and held on the work table 20 of the cutting device via the cutting tape T of the frame unit, and the ring frame F is held by a clamp (not shown). fixed.

Then, the cutting blade 14 is cut into the predetermined division line 17 of the wafer 11 while rotating at a high speed in the direction of the arrow R until the tip of the cutting blade 14 reaches the cutting 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 the arrow X1 while the cutting fluid is supplied at the processing point, thereby forming the planned division line 17 of the wafer 11 to cut the wafer 11 and the first and second transparent substrates 21, 21A 的 剪 沟 27。 21A of the cut groove 27.

The cutting unit 10 is fed in increments in the Y-axis direction, and the same cutting groove 27 is successively formed along a predetermined division line 17 extending in the first direction. Next, after the work clamp 20 is rotated by 90 °, the same cut grooves 27 are formed along all the planned division lines 17 extending in the second direction orthogonal to the first direction to form the state shown in FIG. 8 Thus, the second integrated wafer 25A is divided into the light-emitting diode wafer 31 shown in FIG. 9.

In the embodiment described above, a cutting device is used for the light-emitting diode wafer 31 that divides the second integrated wafer 25A into individual wafers. However, the wafer 11 and the transparent substrate 21, A laser beam having a penetrating wavelength of 21A is irradiated toward the wafer 11 along the planned division line 13 and a plurality of modified layers are formed in the thickness direction inside the wafer 11 and the transparent substrates 21 and 21A. An external force is applied to the second integrated wafer 25A to divide the second integrated wafer 25A into individual light-emitting diode wafers 31 with the modified layer as a starting point of division.

The light-emitting diode wafer 31 shown in FIG. 9 has a first transparent member 21 'attached to the back surface of the LED 13A having the LED circuit 19 on the front surface. In addition, depressions 5, 5A, 5B, or depressions 9 are formed on the front surface of the first transparent member 21 '. A second transparent member 21A 'is attached to the back surface of the first transparent member 21'.

Therefore, in the light-emitting diode wafer 31 shown in FIG. 9, since a recess is formed on the front surface of the first transparent member 21 ', the surface area of the first transparent member 21' is increased. A part of the light emitted from the LED circuit 19 of the light-emitting diode wafer 31 and incident on the first transparent member 21 'is refracted by the recessed portion and enters the first transparent member 21'.

Therefore, when light is refracted and emitted from the first transparent member 21 'and the second transparent member 21A' to the outside, the incident angle at the interface between the first and second transparent members 21 ', 21A' and the air layer. The proportion of light above the critical angle is reduced, the amount of light emitted from the first and second transparent members 21 ′, 21A ′ is increased, and the brightness of the light-emitting diode wafer 31 is increased.

2‧‧‧Mask

4‧‧‧ hole

5, 5A, 5B, 9‧‧‧ depression

10‧‧‧ cutting unit

11‧‧‧Optical element wafer (wafer)

11a, 21a‧‧‧ Front

11b, 21b‧‧‧ back

12‧‧‧ Spindle housing

13‧‧‧Sapphire substrate

13A‧‧‧LED

14‧‧‧ Cutter

15‧‧‧ Stratified body

16‧‧‧Blade cover

17‧‧‧ divided scheduled line

18‧‧‧ cooling nozzle

19‧‧‧LED circuit

20‧‧‧Work clamp table

21‧‧‧The first transparent substrate

21A‧‧‧The second transparent substrate

21’‧‧‧The first transparent member

21A’‧‧‧The second transparent member

24‧‧‧ Condenser (laser head)

25‧‧‧The first integrated wafer

25A‧‧‧2nd integrated wafer

27‧‧‧ cut off the trench

31‧‧‧light-emitting diode chip

R, X1‧‧‧ arrows

T‧‧‧Cutting Tape- + F‧‧‧Ring Frame

X, Y, Z‧‧‧ directions

FIG. 1 is a front perspective view of an optical element wafer. FIG. 2 (A) is a perspective view showing a state where a mask having a plurality of holes corresponding to each LED circuit of the optical element wafer is attached to the front surface of the first transparent substrate, and FIG. 2 (B) is a mask having been applied A perspective view of a state of being attached to the front surface of the first transparent substrate. FIGS. 2 (C) to 2 (E) are partial perspective views showing shapes of depressions formed on the front surface of the first transparent substrate. FIG. 3 (A) is a perspective view showing a state in which a plurality of depressions corresponding to the LED circuits of the optical element wafer are formed on the front surface of the first transparent substrate by irradiation of a laser beam, and FIG. 3 (B) is a perspective view Partial perspective view of the shape. FIG. 4 (A) is a perspective view showing a first integration step in which a first transparent substrate having a plurality of depressions on the front surface is attached to the back surface of a wafer to form an integration, and FIG. 4 (B) is a first integration crystal Round perspective view. FIG. 5 (A) is a perspective view showing a second integration step of attaching the front side of the second transparent substrate to the back surface of the first transparent substrate of the first integrated wafer to perform integration, and FIG. 5 (B) is a first 2 perspective view of integrated wafer. FIG. 6 is a perspective view showing a supporting step of supporting a second integrated wafer with a ring frame through a dicing tape. FIG. 7 is a perspective view showing a step of dividing a second integrated wafer into light-emitting diode wafers. FIG. 8 is a perspective view of a second integrated wafer after the dividing step is completed. FIG. 9 is a perspective view of a light emitting diode wafer according to an embodiment of the present invention.

Claims (5)

A method for manufacturing a light-emitting diode wafer. The method for manufacturing a light-emitting diode wafer is characterized by comprising: a wafer preparation step, preparing a wafer, the wafer having a laminated body layer on a transparent substrate for crystal growth, LED circuits are formed on the front surface of the laminated body layer in areas divided by a plurality of predetermined division lines that cross each other, and the laminated body layer is formed with a plurality of semiconductor layers including a light emitting layer; The front surface or the back surface of at least any one of the 1 transparent substrate or the 2nd transparent substrate forms a plurality of depressions corresponding to each LED circuit; the transparent substrate attaching step, after implementing the transparent substrate processing step, the first transparent substrate And attaching the front surface of the second transparent substrate to the back surface of the first transparent substrate to form an integrated wafer; and a slicing step. After implementing the transparent substrate attaching step, The wafer is cut along with the first and second transparent substrates along the predetermined division line to divide the integrated wafer into individual light-emitting diode crystals. . The method for manufacturing a light-emitting diode wafer according to claim 1, wherein the cross-sectional shape of the depression formed in the transparent substrate processing step is any one of a triangle, a quadrangle, and a circle. The method for manufacturing a light-emitting diode wafer according to claim 1, wherein in the step of processing the transparent substrate, the depression is formed by any one of etching, sandblasting, and laser. The method for manufacturing a light-emitting diode wafer according to claim 1, wherein the first and second transparent substrates are formed of any one of transparent ceramic, optical glass, sapphire, and transparent resin, and in the step of attaching the transparent substrate The first transparent substrate is attached to the back surface of the wafer using a transparent adhesive, and the second transparent substrate is attached to the back surface of the first transparent substrate using a transparent adhesive. A light-emitting diode wafer includes a light-emitting diode having an LED circuit formed on a front surface thereof, a first transparent member attached to a back surface of the light-emitting diode, and a first transparent member attached to a back surface of the first transparent member. 2 transparent members, and depressions are formed on the front surface or the back surface of at least one of the first transparent member and the second transparent member.