CN108400111A - The manufacturing method and light-emitting diode chip for backlight unit of light-emitting diode chip for backlight unit - Google Patents

Abstract

Provided are a method for manufacturing a light-emitting diode chip and the light-emitting diode chip, which can obtain sufficient brightness. This method includes: a wafer preparation step for preparing a wafer having a laminated body layer on a transparent substrate for crystal growth, and forming the laminated body layer on the front surface of the laminated body layer in each region demarcated by a plurality of dividing lines intersecting each other. There is an LED circuit, and the laminate layer is formed with a plurality of semiconductor layers including a light-emitting layer; the first transparent substrate bonding step is to bond the front surface of the first transparent substrate with a plurality of through holes formed in the entire surface area to the wafer. The first integrated wafer is formed on the back side of the first transparent substrate; the second transparent substrate sticking process is to stick the front side of the second transparent substrate with a plurality of air bubbles formed inside on the back side of the first transparent substrate to form the second integrated wafer; and In the dividing step, the wafer is cut together with the first and second transparent substrates along the planned dividing line to divide the second integrated wafer into individual light emitting diode chips.

Description

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

technical field

The invention relates to a method for manufacturing a light emitting diode chip and the light emitting diode chip.

Background technique

On the front surface of a crystal growth substrate such as a sapphire substrate, a GaN substrate, or a SiC substrate, a laminated body layer is formed by laminating an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer. The wafer on which light-emitting devices such as LEDs (Light Emitting Diode: Light Emitting Diode) are formed in the area divided by the plurality of intersecting dividing lines on the laminate layer is cut along the dividing lines and divided into individual light-emitting device chips. The obtained light-emitting device chips are widely used in various electronic devices such as mobile phones, personal computers, and lighting equipment.

Since the light emitted from the light-emitting layer of the light-emitting device chip is isotropic, the light is also irradiated inside the crystal growth substrate and emitted from the back surface and side surfaces of the substrate. However, among the light irradiated inside the substrate, since the incident angle at the interface between the substrate and the air layer is greater than the critical angle, the light is totally reflected at the interface and is trapped inside the substrate, and is not emitted from the substrate to the outside. Therefore, there is a problem of causing a decrease in luminance of the light emitting device chip.

In order to solve this problem, Patent Document 1 describes a light emitting diode (LED) in which a transparent member is attached to the back surface of the substrate in order to prevent light emitted from the light emitting layer from being trapped inside the substrate to improve brightness.

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

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

Contents of the invention

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

According to the invention described in claim 1, there is provided a method of manufacturing a light-emitting diode chip, characterized in that the method of manufacturing a light-emitting diode chip has the following steps: a wafer preparation step, preparing the following wafer: the wafer is formed on a transparent substrate for crystal growth There is a laminated body layer on the upper surface, and LED circuits are respectively formed in each area divided by a plurality of crossing dividing lines on the front surface of the laminated body layer, wherein the laminated body layer is formed with a light-emitting layer. A plurality of semiconductor layers; the first transparent substrate sticking process, the front of the first transparent substrate having a plurality of through holes formed in the entire surface area is pasted on the back surface of the wafer to form the first integrated wafer; the second transparent substrate is pasted process, after implementing the first transparent substrate sticking process, sticking the front surface of the second transparent substrate with a plurality of air bubbles formed inside on the back surface of the first transparent substrate to form a second integrated wafer; and a dividing process, The wafer is cut together with the first transparent substrate and the second transparent substrate along the planned dividing line to divide the second integrated wafer into individual light emitting diode chips.

Preferably, the first transparent substrate and the second transparent substrate are formed of any material among transparent ceramics, optical glass, sapphire, and transparent resin, and the first transparent substrate bonding step and the second transparent substrate bonding process are implemented using a transparent adhesive. process.

According to the invention described in claim 4, there is provided a light emitting diode chip, characterized in that the light emitting diode chip has: a light emitting diode on which an LED circuit is formed on the front surface; a first transparent member having a plurality of through holes on which the front surface is pasted. on the back of the light-emitting diode; and a second transparent member with a plurality of air bubbles inside, the front side of which is pasted on the back of the first transparent member.

Regarding the light-emitting diode chip of the present invention, since the front surface of a first transparent member with a plurality of through holes is pasted on the back of the LED, a second transparent member with a plurality of air bubbles inside is pasted on the back of the first transparent member. Therefore, the light is complicatedly refracted in the first transparent member and the second transparent member to reduce the light enclosed in the first transparent member and the second transparent member, and the light emitted from the first transparent member and the second transparent member The increase of the amount increases the brightness of the light-emitting diode chip.

Description of drawings

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

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

(A) of Fig. 3 is a perspective view showing the front side of the 2nd transparent substrate bonded on the back side of the 1st transparent substrate of the 1st integrated wafer and integrated the 2nd transparent substrate sticking process, Fig. 3 (B) ) is a perspective view of the second integrated wafer.

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

Fig. 5 is a perspective view showing a dividing step of dividing the second integrated wafer into light emitting diode chips.

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

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

Label description

10: cutting unit; 11: optical device wafer (wafer); 13: sapphire substrate; 14: cutting tool; 15: laminate layer; 17: dividing line; 19: LED circuit; 21: first transparent substrate; 21A: 25: 1st integrated wafer; 25A: 2nd integrated wafer; 27: cutting groove; 29: through hole; 29A: air bubble; 31: LED chip.

Detailed ways

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 device wafer (hereinafter, sometimes simply referred to as a wafer) 11 .

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

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

The stacked body layer (epitaxial layer) 15 is formed by making electrons a majority carrier of the n-type semiconductor layer (for example, an n-type GaN layer), a semiconductor layer as a light-emitting layer (for example, an InGaN layer), and holes as a majority carrier. Sub-p-type semiconductor layers (for example, p-type GaN layers) are formed by sequential epitaxial 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 laminated body layer 15 divided by a plurality of dividing lines 17 formed in a lattice. Wafer 11 has front surface 11 a on which LED circuit 19 is formed and rear surface 11 b where sapphire substrate 13 is exposed.

According to the method of manufacturing a light emitting diode chip according to an embodiment of the present invention, first, a wafer preparation step is performed to prepare an optical device wafer 11 shown in FIG. 1 . Next, a transparent substrate preparation step is implemented to prepare the first and second transparent substrates.

After the transparent substrate preparation step is carried out, as shown in FIG. 2(A), a first transparent substrate bonding step is carried out to bond the front surface 21a of the first transparent substrate 21 in which a plurality of through holes 29 are formed in the entire area. on the backside 11b of the wafer 11. (B) of FIG. 2 is a perspective view of the first integrated wafer 25 .

The first transparent substrate 21 is formed of any material among transparent resin, optical glass, sapphire, and transparent ceramics. In this 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 carrying out the first transparent substrate sticking process, as shown in FIG. The second integrated wafer 25A shown in FIG. 3(B) is formed on the back surface of the substrate 21 (second transparent substrate bonding step). The material of the second transparent substrate 21A is also the same as that of the first transparent substrate 21 described above.

Also can replace above-mentioned 1st transparent substrate sticking process and the 2nd transparent substrate sticking process, after sticking the front side of the 2nd transparent substrate 21A on the back side of the 1st transparent substrate 21 and carrying out integration, the back side of the wafer 11 11b is pasted on the front surface 21a of the first transparent substrate 21 .

After the second transparent substrate sticking step is carried out, as shown in FIG. 4 , a supporting step is carried out to stick the second transparent substrate 21A of the second integrated wafer 25A on the dicing tape T attached to the ring frame F on the outer periphery. A frame unit is formed above, and the second integrated wafer 25A is supported by an annular frame F via a 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 second integrated wafer 25A is cut by the cutting device to be divided into individual light emitting diode chips. This dividing step will be described with reference to FIG. 5 .

For example, this dividing step is performed using a known cutting device. As shown in FIG. 5 , 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 tool 14 attached to the front end of the main shaft.

The cutting edge of the cutting tool 14 is formed of, for example, an electroformed grinder on which diamond abrasive grains are fixed by nickel plating, and its tip shape is triangular, square, or semicircular.

A substantially part of the cutting tool 14 is covered by a tool cover (wheel cover) 16. On the tool cover 16, a pair of (only one is shown) cooling nozzles extending horizontally on the back side and the front side of the cutting tool 14 are arranged. 18.

In the dividing step, the second integrated wafer 25A is sucked and held on 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 by a jig (not shown).

Then, while the cutting tool 14 is rotated at high speed in the direction of the arrow R, the front end of the cutting tool 14 is cut into the planned dividing line 17 of the wafer 11 until it reaches the dicing tape T, and the cooling nozzle 18 is directed toward the cutting tool 14 and the wafer 11. The processing point supplies the cutting fluid, and processes and feeds the second integrated wafer 25A in the direction of the arrow X1, whereby the wafer 11 and the first and second transparent substrates 21 and 21A are formed along the planned dividing line 17 of the wafer 11. Cut-off cut-off groove 27.

While index-feeding the cutting unit 10 in the Y-axis direction, similar cutting grooves 27 are sequentially formed along the planned dividing line 17 extending in the first direction. Next, after the chuck table 20 is rotated by 90°, the same cutting groove 27 is formed along all the planned dividing lines 17 extending in the second direction perpendicular to the first direction to become the state shown in FIG. 6 , Accordingly, the second integrated wafer 25A is divided into light emitting diode chips 31 shown in FIG. 7 .

In the above-mentioned embodiment, although the second integrated wafer 25A is divided into individual light-emitting diode chips 31 by using a cutting device, it is also possible to irradiate the wafer 11 along the planned division line 13 and have transparent light for the wafer 11 and the transparent substrates 21 and 21A. The laser beam with a transient wavelength forms a multi-layer modified layer along the thickness direction inside the wafer 11, the first transparent substrate 21, and the second transparent substrate 21A, and then applies an external force to the second integrated wafer 25A to modify it. The second monolithic wafer 25A is divided into individual light emitting diode chips 31 using a layer as a starting point for division.

In the light emitting diode chip 31 shown in FIG. 7 , the first transparent member 21 ′ having a plurality of through holes 29 is pasted on the back surface of the LED 13A, and the LED 13A has the LED circuit 19 on the front surface. Furthermore, a second transparent member 21A' having a plurality of bubbles 29A inside is attached to the back surface of the first transparent member 21'.

Therefore, in the light-emitting diode chip 31 shown in FIG. 7, not only the surface areas of the first and second transparent members 21', 21A' are increased, but also the light is complicated in the first and second transparent members 21', 21A'. The amount of light emitted from the transparent members 21 and 21A' is increased, and the brightness of the light emitting diode chip 31 is improved.

Claims (4)

1. A method for manufacturing a light-emitting diode chip, characterized in that, the method for manufacturing a light-emitting diode chip has the following steps: In the wafer preparation process, a wafer is prepared: the wafer has a laminated body layer on a transparent substrate for crystal growth, and LEDs are respectively formed in regions demarcated by a plurality of dividing lines intersecting each other on the front surface of the laminated body layer. A circuit, wherein the laminate layer is formed with a plurality of semiconductor layers including a light emitting layer; The first transparent substrate sticking step is sticking the front surface of the first transparent substrate having a plurality of through holes formed in the entire surface area on the back surface of the wafer to form a first integrated wafer; In the second transparent substrate bonding step, after the first transparent substrate bonding step is carried out, the front surface of the second transparent substrate having a plurality of air bubbles formed therein is bonded to the back surface of the first transparent substrate to form a second integrated wafer. ;as well as In the dividing step, the wafer is cut together with the first transparent substrate and the second transparent substrate along the planned dividing line to divide the second integrated wafer into individual light emitting diode chips. 2. The manufacturing method of light-emitting diode chip according to claim 1, wherein, Instead of the first transparent substrate sticking step and the second transparent substrate sticking step, after the front side of the second transparent substrate is pasted on the back side of the first transparent substrate for integration, the back side of the wafer is pasted on the back side of the first transparent substrate. on the front side of the first transparent substrate. 3. The manufacturing method of light emitting diode chip according to claim 1, wherein, The first transparent substrate and the second transparent substrate are formed of any material selected from transparent ceramics, optical glass, sapphire, and transparent resin, and the first transparent substrate bonding step and the second transparent substrate bonding step are performed using a transparent adhesive. . 4. A light emitting diode chip, characterized in that the light emitting diode chip has: a light emitting diode having an LED circuit formed on the front side; A first transparent member having a plurality of through holes, the front side of which is pasted on the back side of the LED; and The front side of the second transparent member having a plurality of bubbles inside is pasted on the back side of the first transparent member.