JP2018182168A - Method of manufacturing light emitting diode chip and light emitting diode chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a light emitting diode chip capable of obtaining sufficient brightness and a light emitting diode chip. SOLUTION: Each of having 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 partitioned by a plurality of planned division lines intersecting each other on the surface of the laminate layer. A wafer preparation step of preparing a wafer in which an LED circuit 19 is formed in each region, and a first transparent member 21'in which a plurality of through holes are formed over the entire surface or a second transparent member in which a plurality of bubbles are formed inside. A transparent member processing step of forming a plurality of grooves 23B corresponding to each LED circuit on at least one front surface or back surface of 21A', and a first transparent member while adhering the front surface of the first transparent member to the back surface of the wafer. A transparent member attaching step of attaching the front surface of the second transparent member to the back surface of the member to form an integrated wafer, and cutting the integrated wafer along a planned division line to divide the integrated wafer into individual light emitting diode chips 31. It includes a division process. [Selection diagram] FIG. 9

Description

  The present invention relates to a method of 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 stacked is formed on the surface of a crystal growth substrate such as a sapphire substrate, a GaN substrate, or a SiC substrate. A wafer on which a plurality of light emitting devices such as light emitting diodes (LEDs) are formed in a region partitioned by a planned dividing line is cut along the planned dividing line and divided into individual light emitting device chips, and the divided light emission Device chips are widely used in various electric devices such as mobile phones, personal computers, and lighting devices.

  Since the light emitted from the light emitting layer of the light emitting device chip is isotropic, it is also irradiated to the inside of the crystal growth substrate and the light is emitted also from the back surface and the side surface of the substrate. However, among the light emitted to the inside of the substrate, light having an incident angle at the interface with the air layer of not less than the critical angle is totally reflected at the interface and confined inside the substrate and is not emitted from the substrate to the outside As a result, there is a problem that the luminance of the light emitting device chip is reduced.

  In order to solve this problem, in order to suppress the light emitted from the light emitting layer from being trapped inside the substrate, a light emitting diode in which a transparent member is stuck on the back surface of the substrate to improve the brightness (LED) is described in Unexamined-Japanese-Patent No. 2014-175354.

JP, 2014-175354, A

  However, the light emitting diode disclosed in Patent Document 1 has a problem that although the luminance is slightly improved by sticking the transparent member on the back surface of the substrate, sufficient luminance can not be obtained.

  The present invention has been made in view of these 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 brightness.

  According to the invention of claim 1, there is provided a method of 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; Wafer preparing step of preparing a wafer on which an LED circuit is formed in each area partitioned by a plurality of planned dividing lines intersecting each other on the surface of the first transparent substrate, and a first transparent substrate having a plurality of through holes formed over the entire surface Or a transparent substrate processing step of forming a plurality of grooves corresponding to each LED circuit on at least one of the front surface or the back surface of the second transparent substrate in which a plurality of air bubbles are formed, and the transparent substrate processing step After implementation, the surface of the first transparent substrate is attached to the back surface of the wafer and the surface of the second transparent substrate is attached to the back surface of the first transparent substrate to form an integrated wafer. Board sticking work And dividing the integrated wafer into individual light emitting diode chips by cutting the wafer with the first and second transparent substrates along the dividing lines after performing the transparent substrate bonding step. And providing a method of manufacturing a light emitting diode chip.

  Preferably, the cross-sectional shape of the groove formed in the transparent substrate processing step is any of triangular, square, or semicircular. Preferably, the groove formed in the transparent substrate processing step is formed by any of a cutting blade, etching, sand blast, and laser.

  Preferably, the first and second transparent substrates are formed of any of transparent ceramics, optical glass, sapphire, and transparent resin, and in the transparent substrate bonding step, the first transparent substrate is a wafer with a transparent adhesive. Bonded, the second transparent substrate is bonded to the first transparent substrate with a transparent adhesive.

  According to the invention of claim 5, the light emitting diode chip is a light emitting diode having an LED circuit formed on the surface, and a first transparent member having a plurality of through holes attached to the back surface of the light emitting diode. A second transparent member having a plurality of air bubbles in the inside attached to the back surface of the first transparent member, and at least one of the first transparent member and the second transparent member A light emitting diode chip is provided in which grooves are formed on the front or back surface.

  In the light emitting diode chip according to the present invention, the groove is formed on the front surface or the back surface of at least one of the first transparent member having the plurality of through holes or the second transparent member having the plurality of bubbles therein. In addition to the increase in the surface area of the first transparent member or the second transparent member, the light is complicatedly refracted by the at least two layers of the transparent member and the groove and light is confined in the first and second transparent members. And the amount of light emitted from the first and second transparent members is increased to improve the brightness of the light emitting diode chip.

It is a surface side perspective view of an optical device wafer. FIG. 2 (A) is a perspective view showing a transparent substrate processing step, and FIG. 2 (B) to FIG. 2 (D) are cross-sectional views showing the formed groove shape. In FIG. 3A, the first transparent substrate having a plurality of grooves extending in the first direction is attached to the back surface of the wafer on the surface of the first transparent substrate having a plurality of through holes formed over the entire surface. 3B is a perspective view of the first integrated wafer. FIG. 3B is a perspective view of the first integrated wafer. A first transparent substrate having a plurality of grooves extending in a first direction and a second direction orthogonal to the first direction is provided on the surface, and a plurality of through holes are formed over the entire surface, and is adhered to the back surface of the wafer. It is a perspective view which shows the 1st integration process of wearing and integrating. FIG. 5A shows a second integration step of bonding and integrating the surface of the second transparent substrate having a plurality of bubbles formed therein on the back surface of the first transparent substrate of the first integrated wafer. FIG. 5B is a perspective view of the second integrated wafer. It is a perspective view which shows the support process which supports a 2nd integrated wafer by an annular frame via a dicing tape. It is a perspective view which shows the division process which divides | segments a 2nd integrated wafer into a light emitting diode chip. It is a perspective view of the 2nd integrated wafer after the end of a division process. FIGS. 9A to 9D are perspective views of a light emitting diode chip according to an embodiment of the present invention.

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

  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 surface 11 a on which the epitaxial layer 15 is stacked and a back surface 11 b on which the sapphire substrate 13 is exposed.

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

  The stack layer (epitaxial layer) 15 is an n-type semiconductor layer (for example, an n-type GaN layer) in which electrons are majority carriers, a semiconductor layer (for example, InGaN layer) It forms by carrying out epitaxial growth of the semiconductor layer (for example, p-type GaN layer) in order.

  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 in the laminate layer 15 by being divided by a plurality of planned division lines 17 formed in a lattice shape. The wafer 11 has a 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 of manufacturing a light emitting diode chip of the embodiment of the present invention, first, a wafer preparation step of preparing an optical device wafer 11 as shown in FIG. 1 is performed. Then, a plurality of air bubbles are attached to the surface or the back surface of the first transparent substrate having a plurality of through holes formed over the entire surface to be attached to the back surface 11 b of the wafer 11 or the inside to be attached to the back surface A transparent substrate processing step of forming a plurality of grooves corresponding to the LED circuits 19 on the surface or the back surface of the formed second transparent substrate is performed.

  This transparent substrate processing step is performed, for example, using a well-known cutting device. As shown in FIG. 2A, the cutting unit 10 of the cutting apparatus includes a spindle housing 12, a spindle (not shown) rotatably inserted in the spindle housing 12, and a cutting blade 14 attached to the tip of the spindle. Contains.

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

  The upper half of the cutting blade 14 is covered with a blade cover (wheel cover) 16, and the blade cover 16 has a pair of cooler nozzles (only one is shown) extending horizontally to the back and front sides of the cutting blade 14 18 are provided.

  In the transparent substrate processing step of forming a plurality of grooves 23 on the surface 21 a of the first transparent substrate 21, the first transparent substrate 21 having a plurality of through holes 29 over the entire surface is suctioned and held by a chuck table of a cutting device not shown. Do.

  Then, while rotating the cutting blade 14 at high speed in the direction of arrow R, the surface 21a of the first transparent substrate 21 is cut to a predetermined depth while processing the first transparent substrate 21 held by a chuck table (not shown) in the direction of arrow X1. As a result, the groove 23 extending in the first direction is formed by cutting.

  As shown in FIG. 3, the surface 21a of the first transparent substrate 21 is cut while indexing and feeding the first transparent substrate 21 in the direction orthogonal to the direction of the arrow X1 by the pitch of the planned dividing line 17 of the wafer 11. , And a plurality of grooves 23 extending in the first direction are formed one after another.

  As shown in FIG. 3A, the plurality of grooves 23 formed on the surface 21a of the first transparent substrate 21 may extend in only one direction, or as shown in FIG. A plurality of grooves 23 extending in a first direction and a second direction orthogonal to the first direction may be formed on the surface 21 a of the first transparent substrate 21.

  The groove formed on the surface 21a of the first transparent substrate 21 is a groove 23 having a triangular cross section as shown in FIG. 2 (B), or a groove 23A having a rectangular cross section as shown in FIG. 2 (C), or It may be any of the grooves 23B having a semicircular cross section as shown in FIG. 2 (D).

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

  In the transparent substrate processing step described above, the plurality of grooves 23 are formed on the surface 21 a of the first transparent substrate 21. However, instead of this embodiment, the plurality of grooves 23 is formed on the back surface 21 b of the first transparent substrate 21. May be formed.

  Alternatively, without subjecting the front and back surfaces of the first transparent substrate 21 to any processing, each LED circuit of the wafer 11 is formed on the front surface 21a or the back surface 21b of the second transparent substrate 21A having a plurality of bubbles formed therein. A plurality of grooves 23 may be formed correspondingly. Similarly to the first transparent substrate 21, the second transparent substrate 21A is also formed of any of transparent resin, optical glass, sapphire, and transparent ceramics. The grooves 23 may be formed by etching, sand blast, or laser.

  After carrying out the transparent substrate processing step, the front surface 21a of the first transparent substrate 21 is adhered to the back surface 11b of the wafer 11, and the front surface 21a of the second transparent substrate 21A is adhered to the back surface 21b of the first transparent substrate 21. Implement the transparent substrate bonding process to be worn.

  In this transparent substrate bonding step, first, as shown in FIG. 3A, the surface 21a of the first transparent substrate 21 in which a plurality of grooves 23 are formed on the surface 21a corresponding to the LED circuits 19 of the wafer 11. Then, the back surface 11b of the wafer 11 is adhered with a transparent adhesive, and as shown in FIG. 3B, the wafer 11 and the first transparent substrate 21 are integrated to form a first integrated wafer 25.

  Then, as shown in FIG. 5A, the surface 21a of the second transparent substrate 21A having a plurality of bubbles 29A formed therein is attached to the back surface 21b of the first transparent substrate 21 of the first integrated wafer 25. Then, a second integrated wafer 25A as shown in FIG. 5B is formed.

  The transparent substrate attaching step is not limited to the above-described order, and the first transparent substrate 21 is attached after the surface 21a of the second transparent substrate 21A is attached to the back surface 21b of the first transparent substrate 21. The front surface 21a of the second integrated wafer 25A may be bonded to the back surface 11b of the wafer 11 to form the second integrated wafer 25A.

  After carrying out the transparent substrate bonding step, as shown in FIG. 6, the second transparent substrate 21A of the second integrated wafer 25A is bonded to a dicing tape T whose outer peripheral portion is bonded to the annular frame F. A frame unit is formed, and a supporting step of supporting the second integrated wafer 25A with the annular frame F via the dicing tape T is performed.

  After carrying out the supporting step, the frame unit is put into a cutting device, and the dividing step of cutting the second integrated wafer 25 with the cutting device and dividing it into individual light emitting diode chips is carried out. This division step will be described with reference to FIG.

  As shown in FIG. 7, the cutting unit 10 of the cutting apparatus includes a spindle housing 12, a spindle (not shown) rotatably inserted in the spindle housing 12, and a cutting blade 14 attached to the tip of the spindle. There is.

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

  The upper half of the cutting blade 14 is covered with a blade cover (wheel cover) 16, and the blade cover 16 has a pair of cooler nozzles (only one is shown) extending horizontally to the back and front sides of the cutting blade 14 18 are provided.

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

  Then, while rotating the cutting blade 14 at high speed in the direction of arrow R, the dividing line 17 of the wafer 11 is cut until the tip of the cutting blade 14 reaches the dicing tape T, and the cooler nozzle 18 is used to cut the cutting blade 14 and the wafer 11 By feeding the second integrated wafer 25A in the direction of arrow X1 while supplying the cutting fluid toward the wafer 11, the first transparent substrate 21 and the second transparent substrate 21 along the planned dividing line 17 of the wafer 11. Cutting groove 27 is formed.

  Similar cutting grooves 27 are formed one after another along the planned dividing line 17 extending in the first direction while indexing and feeding the cutting unit 10 in the Y-axis direction. Next, after rotating the chuck table 20 by 90 °, similar cutting grooves 27 are formed along all the planned dividing lines 17 extending in the second direction orthogonal to the first direction, as shown in FIG. By setting the state, the second integrated wafer 25A is divided into light emitting diode chips 31, 31A, 31B and 31C as shown in FIGS. 9A to 9D.

  In the embodiment described above, a cutting device is used to divide the second integrated wafer 25A into the individual light emitting diode chips 31, but at a wavelength having transparency to the wafer 11 and the transparent substrates 21 and 21A. A laser beam is applied to the wafer 11 along the dividing lines 13 to form a plurality of modified layers in the thickness direction inside the wafer 11 and the transparent substrates 21 and 21A, and then the second integrated wafer 25A is formed. An external force may be applied to divide the second integrated wafer 25A into the individual light emitting diode chips 31 using the modified layer as the dividing start point.

  In the light emitting diode chip 31 shown in FIG. 9A, a first transparent member 21 ′ having a groove 23B on the surface is attached to the back surface of the LED 13A having the LED circuit 19 on the surface. The surface of the second transparent member 21A 'is attached to the back surface of the surface' A '.

  In the light emitting diode chip 31A of the second embodiment shown in FIG. 9B, the surface of the first transparent member 21 'having the groove 23B on the back is attached to the back of the LED 13A having the LED circuit 19 on the front, The surface of the second transparent member 21A 'is attached to the back surface of the first transparent member 21'.

  In the light emitting diode chip 31B of the third embodiment shown in FIG. 9C, the surface of the first transparent member 21 'is attached to the back surface of the LED 13A having the LED circuit 19 on the front surface. The surface of the second transparent member 21A 'in which the groove 23B is formed on the front surface is attached to the back surface.

  In the light emitting diode chip 31C of the fourth embodiment shown in FIG. 9D, the surface of the first transparent member 21 'is attached to the back surface of the LED 13A having the LED circuit 19 on the front surface. On the back surface, the surface of the second transparent member 21A 'in which the groove 23B is formed on the back surface is attached.

  In the light emitting diode chips 31, 31A, 31B, 31C according to the above-described embodiment, the light emitted from the LED circuit 19 and incident on the first transparent member 21 'and the second transparent member 21A' is refracted by the groove 23B. Since the amount of light confined in the first and second transparent members 21 ′ and 21A ′ decreases to be incident or emitted, the light emitted to the outside from the first and second transparent members 21 ′ and 21A ′ The amount is increased, and the brightness of the light emitting diode chips 31, 31A, 31B, 31C is improved.

10 Cutting Unit 11 Optical Device Wafer (Wafer)
13 sapphire substrate 14 cutting blade 15 laminated body layer 17 division intended line 19 LED circuit 21 first transparent substrate 21 'first transparent member 21A second transparent substrate 21A' second transparent member 23, 23A, 23B groove 25 first Integrated wafer 25A Second integrated wafer 27 Cutting groove 29 Through hole 29A Bubbles 31, 31A, 31B Light emitting diode chip

Claims (5)

A method of 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 a transparent substrate for crystal growth, and in each of the regions partitioned by a plurality of planned dividing lines crossing each other on the surface of the laminate layer. A wafer preparation step of preparing a wafer on which an LED circuit is formed;
A plurality of first transparent substrates having a plurality of through holes formed over the entire surface or a second transparent substrate having a plurality of air bubbles formed therein are provided corresponding to respective LED circuits on the front surface or the back surface. A transparent substrate processing step of forming a groove;
After carrying out the transparent substrate processing step, the surface of the first transparent substrate is attached to the back surface of the wafer and the surface of the second transparent substrate is attached to the back surface of the first transparent substrate to form an integral body. A transparent substrate bonding step for forming a siliconized wafer;
A dividing step of dividing the integrated wafer into individual light emitting diode chips by cutting the wafer along with the dividing lines with the first and second transparent substrates after performing the transparent substrate bonding step; ,
A method of manufacturing a light emitting diode chip, comprising:   The method for manufacturing a light emitting diode chip according to claim 1, wherein a cross sectional shape of the groove formed in the transparent substrate processing step is any one of a triangular shape, a square shape and a semicircular shape.   The method for manufacturing a light emitting diode chip according to claim 1, wherein the groove is formed by any one of a cutting blade, etching, sand blast, and laser in the transparent substrate processing step.   The first and second transparent substrates are formed of any of transparent ceramics, optical glass, sapphire, and transparent resin, and in the transparent substrate bonding step, the first transparent substrate is formed of a transparent adhesive. The method for manufacturing a light emitting diode chip according to claim 1, wherein the second transparent substrate is attached to the back surface of the wafer, and the second transparent substrate is attached to the back surface of the first transparent substrate using a transparent adhesive. A light emitting diode chip,
A light emitting diode having an LED circuit formed on the surface;
A first transparent member having a plurality of through holes attached to the back surface of the light emitting diode;
A second transparent member having a plurality of air bubbles in the inside attached to the back surface of the first transparent member;
Equipped with
A light emitting diode chip having a groove formed on the surface or the back surface of at least one of the first transparent member and the second transparent member.