TW201812889A - Method for manufacturing light-emitting diode chip and light-emitting diode chip - Google Patents

Abstract

To provide a method for manufacturing a light-emitting diode chip capable of obtaining sufficient luminance, and the light-emitting diode chip. A method for manufacturing a light-emitting diode chip comprises: a wafer preparing step of preparing a wafer which includes a laminate layer in which a plurality of semiconductor layers containing a light-emitting layer are formed on a transparent substrate for crystal growth, and in which an LED circuit is formed in each of the regions partitioned by a plurality of division schedule lines mutually crossing a surface of the laminate layer; a transparent substrate processing step of forming a plurality of grooves corresponding to each LED circuit of the wafer on a rear surface of the transparent substrate; an integrating step of forming an integrated wafer by sticking the surface of the transparent substrate to a rear surface of the wafer after performing the transparent substrate processing step; and a dividing step of dividing the integrated wafer into individual light-emitting diode chips by cutting the wafer together with the transparent substrate along the division schedule lines.

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 a front surface of a crystal growth substrate such as a sapphire substrate, a GaN substrate, or a SiC substrate, a multilayer body layer formed by laminating a plurality of n-type semiconductor layers, light-emitting layers, and p-type semiconductors is formed, and a plurality of LEDs ( A light emitting element such as a light emitting diode (Light Emitting Diode) is formed on the laminated body layer in a region defined by a plurality of intersecting predetermined division lines. The light-emitting element wafers are one by one, and the divided light-emitting element wafers are 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, and to prevent the light emitted from the light-emitting layer from being enclosed inside the substrate, a light-emitting diode (LED) formed by attaching a transparent member to the rear surface of the substrate to improve the brightness has been described in a special feature. In 2014-175354. 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 of claim 1, it is possible to provide a method for manufacturing a light emitting diode wafer, comprising: a wafer preparation step, preparing a wafer, the wafer having a light emitting diode formed on a transparent substrate for crystal growth; A multilayer body layer of a plurality of semiconductor layers, and an LED circuit is formed in each area defined by a plurality of predetermined division lines crossing each other on the front side of the multilayer body layer; a transparent substrate processing step is on the back of the transparent substrate Forming a plurality of grooves corresponding to each LED circuit of the wafer; an integration step, after implementing the transparent substrate processing step, attaching the front surface of the transparent substrate to the back of the wafer to form an integrated wafer; and dividing In the step, the wafer and the transparent substrate are cut together along the predetermined dividing line to divide the integrated wafer into individual light emitting diode wafers.

Preferably, the cross-sectional shape of the groove formed in the transparent substrate processing step is any one of a triangle, a quadrangle, or a semi-circular shape. Preferably, the grooves formed in the processing step of the transparent substrate are formed by any one of a cutter, etching, sandblasting, and laser.

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

According to the invention of 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 the front surface; and a transparent member attached to a back surface of the light-emitting diode; A groove is formed on a surface opposite to the attachment surface of the light-emitting diode. Invention effect

Since the light emitting diode wafer of the present invention has grooves 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, the light emitting layer is also irradiated from the LED light emitting layer and made incident The light to the transparent member is complicatedly refracted in the groove portion, so that the ratio of light having an incident angle at the interface between the transparent member and the air layer above the critical angle when emitted from the transparent member is reduced, and the light from the transparent member is reduced. The amount of emitted light 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 epitaxial 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. Further, a transparent substrate processing step is performed. The transparent substrate processing step is to form a plurality of grooves on the back surface 21 b of the transparent substrate 21 to be attached to the back surface 11 b of the wafer 11 corresponding to the LED circuit 19.

This transparent substrate 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 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 particles are fixed by nickel plating, and the shape of the tip thereof is triangular, quadrangular, or semicircular.

A substantially upper part of the cutting blade 14 is covered with a blade cover (wheel cover) 16. The blade cover 16 is provided with a horizontally elongated one on the back side and the front side of the cutting blade 14. Pairs (only one is shown) of cooling nozzles 18.

In the transparent substrate processing step in which a plurality of grooves 23 are formed on the back surface 21b of the transparent substrate 21, the transparent substrate 21 is sucked and held on a work clamp of a cutting device (not shown). Then, while turning the cutter 14 at a high speed in the direction of the arrow R, it is cut into a predetermined depth on the back surface 21b of the transparent substrate 21, and the transparent substrate 21 held on a work clamp (not shown) is processed in the direction of arrow X1. The groove 23 is formed to be elongated in the first direction by cutting.

The transparent substrate 21 is fed in the direction orthogonal to the direction of the arrow X1 at each pitch of the predetermined division line 17 of the wafer 11, and the back surface 21 b of the transparent substrate 21 is cut as shown in FIG. 3 one by one. A plurality of grooves 23 extending in the first direction are formed.

As shown in FIG. 3 (A), the plurality of grooves 23 formed on the back surface 21b of the transparent substrate 21 may be in a form elongated in only one direction, or may be made as shown in FIG. 3 (B) and transparently formed. A plurality of grooves 23 are formed on the back surface 21 b of the substrate 21 and extend in the first direction and in the second direction orthogonal to the first direction.

The groove formed on the back surface 21b of the transparent substrate 21 is a groove 23 with a triangular cross section as shown in FIG. 2 (B), or a groove 23A with a quadrangular cross section as shown in FIG. 2 (C), or as shown in FIG. 2 Any one of the grooves 23B having a semicircular cross section as shown in (D) may be used.

The transparent substrate 21 may be formed of any one of transparent resin, optical glass, sapphire, and transparent ceramic. In this embodiment, the transparent substrate 21 is formed of a transparent resin such as polycarbonate or acrylic which is more durable than optical glass. In addition, as a method of forming the groove, sandblasting, etching, and laser may be used.

After the transparent substrate processing step of forming a plurality of grooves 23, 23A, and 23B on the back surface 21b of the transparent substrate 21 is performed, an integration step is performed. The integration step is to attach the transparent substrate 21 to the back surface 11b of the wafer 11 to form Integrated wafer 25.

In this integration step, as shown in FIG. 4 (A), the back surface 11b of the wafer 11 is adhered to the back surface 21b with a plurality of grooves 23 extending in the first direction on the back surface 21b with a transparent adhesive. As shown in FIG. 3 (B), the front surface of the substrate 21 is integrated with the transparent substrate 21 to form an integrated wafer 25.

As an alternative embodiment, as shown in FIG. 3 (B), the back surface 11b of the wafer 11 may be bonded with a transparent adhesive, and the back surface 21b of the transparent substrate 21 may have a first direction and a first direction. The front surface 21a of the transparent substrate 21 of the plurality of grooves 23 elongated in the second direction orthogonal to the direction integrates the wafer 11 and the transparent substrate 21. Here, the pitch of the grooves 23 formed on the back surface 21 b of the transparent substrate 21 is a pitch corresponding to the planned division line 17 of the wafer 11.

After the integration step is performed, a support step is performed. The support step is formed by attaching the transparent substrate 21 of the integrated wafer 25 to the dicing tape T whose outer periphery has been attached to the ring frame F as shown in FIG. 5. The frame unit supports the integrated wafer 25 with the ring frame F through the dicing tape T.

After the supporting step is performed, a dividing step is performed, in which the frame unit is put into a cutting device, and the integrated wafer 25 is cut by the cutting device to be divided into individual light emitting diode wafers. This division step will be described with reference to FIG. 6.

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

Then, while cutting the cutter 14 at a high speed in the direction of the arrow R, it cuts into the planned division line 17 of the wafer 11 until the tip of the cutter 14 reaches the dicing tape T, and processes from the cooling nozzle 18 toward the cutter 14 and the wafer 11 Cutting fluid is supplied at a point to process and feed the integrated wafer 25 in the direction of the arrow X1, thereby forming a cutting groove 27 that cuts the wafer 11 and the transparent substrate 21 along the planned division line 17 of the wafer 11.

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 that are extended in the second direction orthogonal to the first direction to form the state shown in FIG. 7. Thus, the integrated wafer 25 is divided into the light-emitting diode wafer 31 as shown in FIG. 8 (A).

In the above-mentioned embodiment, the cutting device is used for the light-emitting diode wafer 31 that divides the integrated wafer 25 into individual wafers. However, it is also possible to make the wafer 11 and the transparent substrate 21 transparent. Laser beams of a characteristic wavelength are 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 substrate 21, and then the integrated wafer 25 is formed. An external force is applied to divide the integrated wafer 25 into individual light-emitting diode wafers 31 with the reforming layer as a starting point for division.

The light-emitting diode wafer 31 shown in FIG. 8A is a transparent member 21A with a back surface of an LED 13A having an LED circuit 19 on the front surface. A groove 23 is formed on the front surface of the transparent member 21A.

Therefore, in the light-emitting diode wafer 31 shown in FIG. 8 (A), 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 wafer 31 and entered into the transparent member 21A is refracted in a complicated manner at the groove 23 and is emitted to the outside.

Therefore, when light is emitted from the transparent member 21A to the outside, the proportion of light having an incident angle at the interface between the transparent member 21A and the air layer that is equal to or greater than the critical angle is reduced, and the amount of light emitted from the transparent member 21A is reduced. The amount is increased, and the brightness of the light-emitting diode wafer 31 is increased.

In the light-emitting diode wafer 31A shown in (B) of FIG. 8, a transparent structure 21A having a cross-section-shaped groove 23A on the back surface is attached to the LED 13A with a transparent adhesive. Also in the light-emitting diode wafer 31A of this embodiment, similarly to the light-emitting diode wafer 31 shown in FIG. 8 (A), a part of the light emitted from the LED circuit 19 and entering the transparent member 21 is reflected in The section quadrangular groove 23A is refracted in a complicated manner and is projected to the outside.

Therefore, when light is emitted from the inside of the transparent member 21A to the outside, the proportion of light whose incident angle at the interface between the transparent member 21A and the air layer becomes greater than a critical angle is reduced, and the light emitted from the transparent member 21A is reduced. The amount is increased, and the brightness of the light-emitting diode wafer 31A is increased.

8 (C), a perspective view of a light-emitting diode wafer 31B according to another embodiment is shown. In the light-emitting diode wafer 31B of this embodiment, a semi-circular groove 23B is formed on the back surface of the transparent member 21A in a direction orthogonal to each other. Therefore, the light-emitting diode wafer 31B is emitted from the LED circuit 19 and enters into transparency. A part of the light in the member 21A is complicatedly refracted in the groove 23B and emitted to the outside.

Therefore, when light is emitted from the transparent member 21A to the outside, the amount of light whose incident angle at the interface between the transparent member 21A and the air layer becomes greater than a critical angle is reduced, and the light emitted from the transparent member 21A to the outside is reduced. The amount of light is increased, and the brightness of the light-emitting diode wafer 31B is increased.

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‧‧‧Laminated body layer (crystalline film layer)

16‧‧‧Blade cover

17‧‧‧ divided scheduled line

18‧‧‧ cooling nozzle

19‧‧‧LED circuit

20‧‧‧Work clamp table

21‧‧‧ transparent substrate

21A‧‧‧Transparent member

23, 23A, 23B‧‧‧ trench

25‧‧‧Integrated wafer

27‧‧‧ cut off the trench

31, 31A, 31B ‧‧‧ Light Emitting Diode Chips

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 the processing steps of the transparent substrate, and FIGS. 2 (B) to 2 (D) are cross-sectional views showing the shape of the grooves formed. FIG. 3 (A) is a rear perspective view of a transparent substrate having a plurality of grooves extending in the first direction on the back surface, and FIG. 3 (B) is a transparent substrate having a plurality of grooves crossing each other on the back surface. Perspective view of the back side. FIG. 4 (A) is a perspective view showing an integration step of attaching a transparent substrate having a plurality of grooves on the back surface to the back surface of the wafer to form an integration, and FIG. 4 (B) is a perspective view of the integrated wafer. FIG. 5 is a perspective view showing a supporting step of supporting an integrated wafer with a ring frame through a dicing tape. FIG. 6 is a perspective view showing a step of dividing an integrated wafer into light emitting diode wafers. FIG. 7 is a perspective view of the integrated wafer after the dividing step. 8 (A) to 8 (C) are perspective views of a light emitting diode device according to an embodiment of the present invention.

Claims (5)

A method for manufacturing a light emitting diode wafer, comprising: a wafer preparation step, preparing a wafer, the wafer having a laminated body layer formed with a plurality of semiconductor layers including a light emitting layer on a transparent substrate for crystal growth; LED circuits are formed on the front side of the multilayer body by areas that are divided by a plurality of predetermined division lines that cross each other. In the transparent substrate processing step, the LED circuits on the back of the transparent substrate correspond to the LED circuits on the wafer. Forming a plurality of grooves; an integration step, after implementing the transparent substrate processing step, attaching a front side of the transparent substrate to a back surface of the wafer to form an integrated wafer; and a slicing step along the predetermined division line The wafer and the transparent substrate are cut together to divide the integrated wafer into individual light emitting diode wafers. The method for manufacturing a light-emitting diode wafer according to claim 1, wherein a cross-sectional shape of the groove formed in the transparent substrate processing step is any one of a triangle, a quadrangle, and a semicircle. The method for manufacturing a light-emitting diode wafer according to claim 1, wherein in the transparent substrate processing step, the groove is formed by any one of a cutter, etching, sandblasting, and laser. The method for manufacturing a light-emitting diode wafer according to claim 1, wherein the transparent substrate is formed of any one of transparent ceramic, optical glass, sapphire, and transparent resin, and in the integration step, the transparent substrate is made of transparent adhesive. Agent to attach to the wafer. A light-emitting diode wafer includes: a light-emitting diode having an LED circuit formed on a front surface thereof; and a transparent member attached to a back surface of the light-emitting diode; and the transparent member is attached to the light-emitting diode. A groove is formed on the surface on the opposite side of the surface.