KR102296118B1 - Method for manufacturing a light emitting diode chip and a light emitting diode chip - Google Patents

Abstract

An object of the present invention is to provide a method for manufacturing a light emitting diode chip and a light emitting diode chip capable of obtaining sufficient luminance.
A method for 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; A wafer preparation step of preparing a wafer having each LED circuit formed thereon; a wafer backside processing step of forming a plurality of recesses or grooves corresponding to each LED circuit on the back surface of the wafer; and a first transparent substrate on the back surface of the wafer A first transparent substrate adhering step of forming a first integrated wafer by adhering the surface of A second transparent substrate adhering step of forming an integrated wafer, and a division step of cutting the wafer together with the first and second transparent substrates along the division line to divide the second integrated wafer into individual light emitting diode chips characterized by including.

Description

Method for manufacturing a light emitting diode chip and a light emitting diode chip

The present invention relates to a method for 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 laminated is formed on the surface of a substrate for crystal growth such as a sapphire substrate, a GaN substrate, or a SiC substrate, and a plurality of division lines intersecting the laminate layer are formed. A wafer in which a plurality of light emitting devices such as LEDs (Light Emitting Diodes) are formed in an area partitioned by the slit is cut along a division scheduled line and divided into individual light emitting device chips, and the divided light emitting device chips are used for cell phones, personal computers, It is widely used in various electric devices such as lighting equipment.

Since the light emitted from the light emitting layer of the light emitting device chip has isotropy, it is also irradiated to the inside of the substrate for crystal growth, and light is emitted from the back and side surfaces of the substrate as well. However, among the light irradiated to the inside of the substrate, light whose incident angle at the interface with the air layer is greater than or equal to the critical angle is totally reflected at the interface, confined inside the substrate, and is not emitted from the substrate to the outside, thereby reducing the luminance of the light emitting device chip. There is a problem that it causes.

In order to solve this problem, in order to suppress the light emitted from the light emitting layer from being confined inside the substrate, a light emitting diode (LED) in which a transparent member is adhered to the back surface of the substrate to improve luminance. It describes in Unexamined-Japanese-Patent No. 2014-175354.

[Patent Document 1] Japanese Patent Laid-Open No. 2014-175354

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

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

According to the invention as set forth in claim 1, there is provided a method for 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 intersecting layers on the surface of the laminate layer A wafer preparation step of preparing a wafer each having an LED circuit formed thereon in each region partitioned by a line to be divided; A first transparent substrate bonding step of bonding the surface of the first transparent substrate to the back surface of the wafer to form a first integrated wafer, and after performing the first transparent substrate bonding step, a second transparent substrate is formed on the back surface of the first transparent substrate A second transparent substrate bonding step of bonding the surface of a substrate to form a second integrated wafer, and cutting the wafer along with the first and second transparent substrates along the scheduled division line to separate the second integrated wafer There is provided a method of manufacturing a light emitting diode chip comprising a division process of dividing the light emitting diode chip.

Preferably, the recesses or grooves formed in the wafer back surface processing step are formed by any one of a cutting blade, etching, sand blasting, and laser.

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 bonding steps are performed using a transparent adhesive.

According to the invention according to claim 4, there is provided a light emitting diode chip, comprising: a light emitting diode having an LED circuit formed on its surface and a recess or groove formed on its rear surface; a first transparent member having a surface attached to the rear surface of the light emitting diode; There is provided a light emitting diode chip comprising a second transparent member whose surface is adhered to the back surface of the first transparent member.

In the light emitting diode chip of the present invention, a surface of a first transparent member is adhered to a rear surface of a light emitting diode having an LED circuit formed on the surface and a recess or groove formed on the rear surface, and a second transparent member is attached to the rear surface of the first transparent member Since the surface of the , light is complicatedly refracted in the recesses or grooves and the first and second transparent members to reduce the light confined in the first and second transparent members, and the first and second transparent members The amount of light emitted from the light emitting diode chip is increased to improve the luminance of the light emitting diode chip.

1 is a front side perspective view of an optical device wafer;
FIG. 2A is a perspective view illustrating a back surface processing step of a wafer by a cutting blade, and FIGS. 2B to 2D are cross-sectional views illustrating the formed groove shape.
3A is a rear perspective view of a wafer having a plurality of grooves extending in a first direction formed on the back surface of the wafer, and FIG. 3B is a first direction formed on the back surface of the wafer and orthogonal to the first direction. It is a rear side perspective view of a wafer in which a plurality of grooves extending in the second direction are formed.
Fig. 4 (A) is a perspective view showing a state that a mask is attached to the back surface of the 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, Fig. 4 ( C) to 4(E) are partial perspective views of a wafer showing the shape of a recess formed on the back surface of the wafer.
FIG. 5A is a perspective view showing a state in which a groove is formed on the back surface of the wafer by a laser beam, FIG. 5B is a partial cross-sectional view of the wafer showing the groove shape, and FIG. 5C is a laser beam A perspective view showing a state in which a circular concave portion is formed on the back surface of the wafer by a beam, and FIG. 5D is a partial perspective view of the wafer showing the formed circular concave portion.
Fig. 6(A) is a perspective view showing a first transparent substrate adhering process in which the front surface of the first transparent substrate is adhered to the back surface of the wafer to be integrated, and Fig. 6(B) is a perspective view of the first integrated wafer.
Fig. 7(A) is a perspective view showing a second transparent substrate adhering process in which the surface of the second transparent substrate is adhered to the back surface of the first transparent substrate of the first integrated wafer to be integrated, and Fig. 7(B) is the second It is a perspective view of an integrated wafer.
8 is a perspective view illustrating a supporting process of supporting a second integrated wafer with an annular frame through a dicing tape.
9 is a perspective view illustrating a division process of dividing a second integrated wafer into a light emitting diode chip.
10 is a perspective view of the second integrated wafer after the division process has been completed.
11 is a perspective view of a light emitting diode chip according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 side perspective view of an optical device wafer (hereinafter, may simply be abbreviated as a wafer) 11 .

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 front 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. Instead of the sapphire substrate 13, a GaN substrate or a SiC substrate may be employed.

The laminate layer (epitaxial layer) 15 is an n-type semiconductor layer in which electrons are majority carriers (eg, n-type GaN layer), a semiconductor layer (eg, InGaN layer) that becomes a light emitting layer, and p in which holes are majority carriers. It is formed by sequentially epitaxially growing a type semiconductor layer (eg, a p-type GaN layer).

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

This wafer back surface processing process is performed using a well-known cutting apparatus, for example. As shown in FIG. 2A, 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 a tip of the spindle. It includes a mounted cutting blade (14).

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

An approximately upper half of the cutting blade 14 is covered with a blade cover (wheel cover) 16 , and the blade cover 16 has a pair (only one) extending horizontally on the depth side and the front side of the cutting blade 14 . shown) a cooler nozzle 18 is disposed.

In the wafer back surface processing step of forming the plurality of grooves 3 in the back surface 11b of the wafer 11 , the front surface 11a of the wafer 11 is sucked and held by a chuck table of a cutting device (not shown). Then, while the cutting blade 14 is rotated at a high speed in the direction of the arrow R, a predetermined depth is cut into the back surface 11b of the wafer 11, and the wafer 11 held on a chuck table (not shown) is moved by the arrow X1. By machining feed in the direction, the groove 3 extending in the first direction is formed by cutting.

The back surface 11b of the wafer 11 is cut while the wafer 11 is indexed and transferred at each pitch of the division line 17 of the wafer 11 in a direction orthogonal to the direction of the arrow X1, as shown in FIG. As shown in A), a plurality of grooves 3 extending in the first direction are sequentially formed.

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

The groove formed in the back surface 11b of the wafer 11 is a groove 3 having a triangular cross-section as shown in Fig. 2B, or a rectangular cross-section as shown in Fig. 2C. may be any one of the grooves 3A of , or the grooves 3B having a semicircular cross-section as shown in Fig. 2D.

Instead of the embodiment in which a plurality of grooves 3 , 3A, 3B are formed by cutting on the back surface 11b of the wafer 11 , a plurality of grooves 3 , 3A and 3B are formed on the back surface 11b of the wafer 11 corresponding to the LED circuit 19 . It may be made to form a recessed part of In this embodiment, as shown in FIG. 4A , 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. 4B , the holes 4 of the mask 2 correspond to the respective LED circuits 19 of the wafer 11 and are adhered to the back surface 11b of the wafer 11 . Then, as shown in FIG. 4C , on the back surface 11b of the wafer 11 by wet etching or plasma etching, a triangular concave corresponding to the shape of the hole 4 of the mask 2 . form part (5).

By changing the shape of the hole 4 of the mask 2 to a square shape or a circular shape, a rectangular recess 5A as shown in FIG. 4D is formed on the back surface 11b of the wafer 11 . ), or a circular recess 5B may be formed on the back surface 11b of the wafer 11 as shown in FIG. 4E.

As a modified example of this embodiment, the mask 2 is adhered to the back surface 11b of the wafer 11, and then sandblasting is applied to the back surface 11b of the wafer 11 in FIG. 4(C). ), a triangular-shaped concave portion 5 as shown in Fig. 4(D), or a square-shaped concave portion 5A as shown in Fig. 4(D), or a circular shape as shown in Fig. 4(E). You may make it form the recessed part 5B.

A laser processing apparatus may be used to form a plurality of grooves or a plurality of recesses corresponding to the LED circuits 19 on the back surface 11b of the wafer 11 . In the first embodiment by laser processing, as shown in FIG. 5A , a laser beam of a wavelength (eg, 266 nm) having absorptivity to the wafer 11 is directed to a condenser (laser head) 24 . While irradiating the back surface 11b of the wafer 11 from the 11) is formed by ablation on the back surface 11b.

The back surface 11b of the wafer 11 is ablated while transferring the wafer 11 in a direction orthogonal to the direction of the arrow X1 at each pitch of the line 17 to be divided. A plurality of grooves 7 extending in the direction are sequentially formed. The cross-sectional shape of the groove 7 may be, for example, a semicircular shape, as shown in FIG. 5B , or other shapes.

As an alternative embodiment, as shown in FIG. 5(C), a pulsed laser beam of a wavelength having absorptivity (eg, 266 nm) is intermittently irradiated from the condenser 24 to the wafer 11, and the wafer ( You may make it form the some recessed part 9 corresponding to the LED circuit 19 in the back surface 11b of 11). The shape of the concave portion 9 is usually a circular shape as shown in Fig. 5(D) corresponding to the spot shape of the laser beam.

After performing the wafer back surface processing step, as shown in FIG. 6A , the first transparent substrate bonding in which the front surface 21a of the first transparent substrate 21 is attached to the back surface 11b of the wafer 11 . carry out the process. 6B is a perspective view of the first integrated wafer 25 .

The first transparent substrate 21 is formed of any one of transparent resin, optical glass, sapphire, and transparent ceramics. In this embodiment, the 1st and 2nd transparent substrates were formed with transparent resins, such as polycarbonate and an acrylic resin, which are durable compared with optical glass.

After performing the first transparent substrate adhering step, as shown in FIG. 7A , the surface 21a of the second transparent substrate 21A is applied to the first transparent substrate 21 of the first integrated wafer 25 . is adhered to the back surface of (second transparent substrate adhering step), and a second integrated wafer 25A as shown in FIG. 7B is formed. The material of the second transparent substrate 21A is also the same as that of the above-described first transparent substrate 21 .

Instead of the first transparent substrate adhering step and the second transparent substrate adhering step described above, the surface of the second transparent substrate 21A is attached to the back surface of the first transparent substrate 21 to be integrated, and then the first transparent substrate 21 ), the back surface 11b of the wafer 11 may be adhered to the front surface 21a.

After performing the second transparent substrate adhering step, as shown in FIG. 8 , a dicing tape T in which the outer periphery of the second transparent substrate 21A of the second integrated wafer 25A is adhered to the annular frame F. A support step of supporting the second integrated wafer 25A with the annular frame F through the dicing tape T is performed to form a frame unit.

After carrying out the supporting step, the frame unit is put into a cutting device, and the second integrated wafer 25A is cut with the cutting device and divided into individual light emitting diode chips. This division process is demonstrated with reference to FIG.

This division process is performed using, for example, a well-known cutting device. 9, 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 a cutting blade mounted on the tip of the spindle. (14) is included.

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

An approximately upper half of the cutting blade 14 is covered with a blade cover (wheel cover) 16 , and the blade cover 16 has a pair (only one) extending horizontally on the depth side and the front side of the cutting blade 14 . shown) a cooler nozzle 18 is disposed.

In the division process, the second integrated wafer 25A is sucked and held by the chuck table 20 of the cutting device through the dicing tape T of the frame unit, and the annular frame F is clamped and fixed with a clamp (not shown). do.

Then, while rotating the cutting blade 14 at high speed in the direction of the arrow R, the tip of the cutting blade 14 cuts into the division scheduled line 17 of the wafer 11 until the tip of the cutting blade 14 touches the dicing tape T, While supplying the cutting fluid from the cooler nozzle 18 toward the processing point of the cutting blade 14 and the wafer 11, the second integrated wafer 25A is processed and transported in the direction of the arrow X1, whereby the A cutting groove 27 for cutting the wafer 11 and the first and second transparent substrates 21 and 21A is formed along the dividing line 17 .

While the cutting unit 10 is fed by indexing in the Y-axis direction, the same cutting grooves 27 are sequentially formed along the dividing line 17 extending in the first direction. Subsequently, after rotating the chuck table 20 by 90°, the same cut grooves 27 are formed along all the divisional lines 17 extending in the second direction orthogonal to the first direction, as shown in FIG. In this state, the second integrated wafer 25A is divided into light emitting diode chips 31 as shown in FIG.

In the above-described embodiment, a cutting device is used to divide the second integrated wafer 25A into individual light emitting diode chips 31, but having transparency to the wafer 11 and the transparent substrates 21 and 21A. A laser beam of a wavelength is irradiated to the wafer 11 along the dividing line 13, and a plurality of layers are formed inside the wafer 11 and the first transparent substrate 21 and the second transparent substrate 21A in the thickness direction. A modified layer may be formed and then an external force may be 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 division starting point.

In the light emitting diode chip 31 shown in Fig. 11, a first transparent member 21' is adhered to the rear surface of the LED 13A having the LED circuit 19 on the surface and the recessed portion formed on the rear surface. Moreover, the 2nd transparent member 21A' is pasted on the back surface of the 1st transparent member 21'.

Accordingly, in the light emitting diode chip 31 shown in Fig. 11, in addition to increasing the surface areas of the first and second transparent members 21' and 21A', light is transmitted through the recesses 5 and the first and second Light that is complicatedly refracted in the transparent members 21' and 21A' and is confined in the transparent member is reduced, and the amount of light emitted from the transparent members 21' and 21A' is increased, so that the Brightness is improved.

2: Mask 3, 3A, 3B: Home
4: hole 5, 5A, 5B: recess
7: groove 9: recess
10 cutting unit 11 optical device wafer (wafer)
13: sapphire substrate 14: cutting blade
15: laminate layer 17: division scheduled line
19: LED circuit 21: first transparent substrate
21A: second transparent substrate 25: first integrated wafer
25A: second integrated wafer 27: cutting groove
31: light emitting diode chip

Claims (4)

A method for manufacturing a light emitting diode chip, comprising:
It has a laminate layer in which a plurality of semiconductor layers including a light emitting layer are formed on the surface of a transparent substrate for crystal growth, and an LED circuit is respectively provided in each region partitioned by a plurality of division lines intersecting each other on the surface of the laminate layer. A wafer preparation process of preparing the formed wafer;
A wafer back surface processing step of forming a plurality of recesses or grooves in correspondence with each LED circuit on the back surface of the transparent substrate for crystal growth, wherein the plurality of recesses or grooves are formed on the back surface of the transparent substrate for crystal growth. The wafer back surface processing process, which is formed to be spaced apart from each other by the pitch of the line to be divided;
a first transparent substrate adhering step of forming a first integrated wafer by adhering the surface of the first transparent substrate to the back surface of the transparent substrate for crystal growth;
a second transparent substrate adhering step of forming a second integrated wafer by attaching the surface of a second transparent substrate to the back surface of the first transparent substrate after performing the first transparent substrate adhering step;
A division process of dividing the second integrated wafer into individual light emitting diode chips by cutting the wafer together with the first and second transparent substrates along the division line
including,
A method for manufacturing a light emitting diode chip, wherein in the light emitting diode chip obtained by the dividing step, side surfaces of the transparent substrate for crystal growth and the first and second transparent substrates are coplanar. 2 . The first transparent substrate according to claim 1 , wherein, instead of the first transparent substrate bonding step and the second transparent substrate bonding step, a surface of the second transparent substrate is attached to the back surface of the first transparent substrate and integrated, and then the first transparent substrate is integrated. A method for manufacturing a light emitting diode chip, wherein the back surface of the wafer is adhered to the surface of the substrate. The method of claim 1, 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 bonding processes are performed using a transparent adhesive. A method of manufacturing a light emitting diode chip. A light emitting diode chip comprising:
A light emitting diode in which an LED circuit is formed on the surface of a transparent substrate, and a recess or groove is formed on the back surface of the transparent substrate;
a first transparent member having a surface attached to the back surface of the transparent substrate;
A second transparent member having a surface attached to the rear surface of the first transparent member
to provide
The light emitting diode chip, characterized in that the transparent substrate and side surfaces of the first transparent member and the second transparent member form a coplanar surface.

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