JP2018041783A - Light-emitting diode chip manufacturing method and light-emitting diode chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting diode chip manufacturing method and a light-emitting diode chip which can provide sufficient brightness.SOLUTION: A light-emitting diode chip manufacturing method comprises: a wafer preparation step of preparing a wafer which has a laminate layer where a plurality of semiconductor layers including a luminescent layer is formed on a transparent substrate for crystal growth and on which LED circuits are formed on a surface of the laminate layer in respective regions partitioned by a plurality of division scheduled lines which cross each other; a transparent substrate processing step of forming on a surface and a rear face of a transparent substrate where a plurality of through holes are formed across a whole area, a plurality of depressions corresponding the respective LED circuits of the wafer; an integration step of attaching the surface of the transparent substrate to a rear face of the wafer to form an integrated wafer after performing the transparent substrate processing step; and a division step of cutting the wafer along the division scheduled lines together with the transparent substrate to divide the integrated wafer into individual light-emitting diode chips.SELECTED DRAWING: Figure 4

Description

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

  A stacked body 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 in which a plurality of light emitting devices such as LEDs (Light Emitting Diodes) are formed in a region partitioned by the planned division line is cut along the planned division 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, the light is emitted also to the inside of the crystal growth substrate, and the light is also emitted from the back and side surfaces of the substrate. However, of the light irradiated to the inside of the substrate, light whose incident angle at the interface with the air layer is greater than the critical angle is totally reflected at the interface and confined inside the substrate, and is not emitted outside from the substrate. Therefore, there is a problem that the luminance of the light emitting device chip is lowered.

  In order to solve this problem, a light emitting diode in which a transparent member is attached to the back surface of the substrate to improve the luminance in order to prevent light emitted from the light emitting layer from being confined inside the substrate. (LED) is described in Japanese Patent Application Laid-Open No. 2014-175354.

JP 2014-175354 A

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

  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 that can obtain sufficient luminance.

  According to invention of Claim 1, it is a manufacturing method of a light emitting diode chip | tip, Comprising: It has a laminated body layer in which the several semiconductor layer containing a light emitting layer was formed on the transparent substrate for crystal growth, This laminated body layer A wafer preparation step of preparing a wafer in which LED circuits are formed in each region partitioned by a plurality of division lines intersecting each other on the surface, a surface of a transparent substrate on which a plurality of through holes are formed over the entire surface, and After carrying out the transparent substrate processing step for forming a plurality of depressions corresponding to each LED circuit of the wafer on the back surface and the transparent substrate processing step, the surface of the transparent substrate is adhered to the back surface of the wafer and integrated An integration step for forming a wafer, and a division step for cutting the wafer together with the transparent substrate along the division line to divide the integrated wafer into individual light emitting diode chips; LED chip production method of which is characterized by comprising is provided.

  Preferably, the cross-sectional shape of the recess formed in the transparent substrate processing step is any one of a triangular shape, a quadrangular shape, and a circular shape. Preferably, the recess formed in the transparent substrate processing step is formed by any one of etching, sandblasting, and laser.

  Preferably, the transparent substrate is formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin, and in the integration step, the transparent substrate is bonded to the wafer with a transparent adhesive.

  According to the invention of claim 5, a light-emitting diode chip comprising a light-emitting diode having an LED circuit formed on the surface and a transparent member having a plurality of through-holes attached to the back surface of the light-emitting diode. And a light emitting diode chip in which depressions are formed on the front surface and the back surface of the transparent member.

  Since the light emitting diode chip of the present invention has depressions formed on the surface and the back surface of the transparent member having a plurality of through-holes attached to the back surface of the LED, in addition to increasing the surface area of the transparent member, Light emitted from the light emitting layer and incident on the transparent member is refracted in a complicated manner at the recessed portion, and light emitted from the transparent member is refracted in a complicated manner at the recessed portion. The ratio of the light whose incident angle at the interface is greater than or equal to the critical angle is reduced, the amount of light emitted from the transparent member is increased, and the luminance of the light emitting diode chip is improved.

It is a surface side perspective view of an optical device wafer. FIG. 2A is a perspective view showing a state in which a mask having a plurality of holes corresponding to each LED circuit of the optical device wafer is attached to the surface of the transparent substrate, and FIG. FIG. 2 (C) to FIG. 2 (E) are partial perspective views showing the shape of the depression formed on the surface of the transparent substrate. 3A is a perspective view showing a state in which a plurality of depressions corresponding to each LED circuit of the optical device wafer are formed on the surface of the transparent substrate by laser beam irradiation, and FIG. 3B is a portion showing the shape of the depressions. It is a perspective view. 4A is a cross-sectional view of a transparent substrate having circular recesses on the front and back surfaces of the transparent substrate, and FIG. 4B is a view of a transparent substrate having recesses formed by laser processing on the front and back surfaces of the transparent substrate. It is sectional drawing. FIG. 5A is a perspective view showing an integration process in which a transparent substrate having a plurality of depressions on the front surface and the back surface is attached to the back surface of the wafer and integrated, and FIG. 5B is a perspective view of the integrated wafer. is there. It is a perspective view which shows the support process which supports an integrated wafer with a cyclic | annular flame | frame via a dicing tape. It is a perspective view which shows the division | segmentation process which divides | segments an integrated wafer into a light emitting diode chip. It is a perspective view of the integrated wafer after completion | finish of a division | segmentation process. 1 is a perspective view 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, there is shown a front side perspective view of an optical device wafer 11 (hereinafter sometimes simply referred to as a wafer) 11.

  The optical device wafer 11 is configured by laminating an epitaxial layer (laminated body layer) 15 such as gallium nitride (GaN) on a sapphire substrate 13. The optical device wafer 11 has a front surface 11a on which an epitaxial layer 15 is stacked 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 crystal growth substrate. However, a GaN substrate or a SiC substrate may be employed instead of the sapphire substrate 13.

  The stacked body layer (epitaxial layer) 15 includes an n-type semiconductor layer (for example, an n-type GaN layer) in which electrons are majority carriers, a semiconductor layer (for example, an InGaN layer) that is a light emitting layer, and a p in which holes are majority carriers. It is formed by epitaxially growing a type semiconductor layer (for example, a p-type GaN layer) in this order.

  The sapphire substrate 13 has a thickness of 100 μm, for example, and the laminate layer 15 has a thickness of 5 μm, for example. A plurality of LED circuits 19 are defined on the laminate layer 15 by a plurality of division lines 17 formed in a lattice pattern. 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 light emitting diode chip manufacturing method of the embodiment of the present invention, first, a wafer preparation step for preparing an optical device wafer 11 as shown in FIG. 1 is performed. Then, a transparent substrate processing step for forming a plurality of depressions corresponding to the LED circuit 19 on the front surface 21a and the back surface 21b of the transparent substrate 21 having a plurality of through holes 29 to be bonded to the back surface 11b of the wafer 11 is performed. To do.

  In this transparent substrate processing step, for example, as shown in FIG. 2A, 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. 2B, the holes 4 of the mask 2 are attached to the surface 21 a of the transparent substrate 21 so as to correspond to the LED circuits 19 of the wafer 11.

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

  By changing the shape of the hole 4 of the mask 2 to a rectangular shape or a circular shape, a rectangular recess 5A as shown in FIG. 2D is formed on the surface 21a of the transparent substrate 21, or FIG. A circular recess 5B may be formed on the surface 21a of the transparent substrate 21 as shown in FIG.

  The transparent substrate 21 is formed from any one of transparent resin, optical glass, sapphire, and transparent ceramics. In the present embodiment, the transparent substrate 21 is formed from a transparent resin such as polycarbonate or acrylic that is more durable than optical glass.

  After the transparent substrate processing step for forming the plurality of depressions 5, 5 </ b> A, or 5 </ b> B on the front surface 21 a of the transparent substrate 21 is completed, the plurality of depressions 5 corresponding to the LED circuits 19 of the wafer 11 are also formed on the back surface 21 b of the transparent substrate 21. , 5A, or 5B is performed.

  As a modification of the present embodiment, the mask 2 is attached to the front surface 21a or the back surface 21b of the transparent substrate 21, and then sandblasting is performed, whereby the front surface 21a and the back surface 21b of the transparent substrate 21 are subjected to FIG. Alternatively, a triangular recess 5 as shown in FIG. 2, a quadrangular recess 5A as shown in FIG. 2D, or a circular recess 5B as shown in FIG. 2E may be formed.

  A laser processing apparatus may be used to form a plurality of depressions corresponding to the LED circuit 19 on the front surface 21a and the back surface 21b of the transparent substrate 21 having a plurality of through holes 29 over the entire surface. In the embodiment by laser processing, as shown in FIG. 3A, a laser beam having a wavelength (for example, 266 nm) having an absorptivity with respect to the transparent substrate 21 is transmitted from the condenser (laser head) 24 to the transparent substrate 21. A plurality of depressions corresponding to the LED circuit 19 of the wafer 11 are formed on the surface 21a of the transparent substrate 21 by processing and feeding a chuck table (not shown) holding the transparent substrate 21 in the direction of the arrow X1 while intermittently irradiating the surface 21a. 9 is formed by ablation.

  While the transparent substrate 21 is indexed and fed in the direction orthogonal to the arrow X1 direction by the pitch of the division planned line 17 of the wafer 11, the surface 21a of the transparent substrate 21 is ablated to form a plurality of recesses 9 one after another. The cross-sectional shape of the recess 9 is usually a circular shape as shown in FIG. 3B corresponding to the spot shape of the laser beam.

  Next, the front and back of the transparent substrate 21 are reversed, the front surface 21a side of the transparent substrate 21 is sucked and held by the chuck table of the laser processing apparatus, and the back surface 21b of the transparent substrate 21 is exposed. Then, similarly to the formation of the plurality of depressions 9 on the surface 21a of the transparent substrate 21, the transparent substrate 21 is held while the laser beam is intermittently irradiated from the condenser 24 to the back surface 21b of the transparent substrate 21 (not shown). By processing and feeding the chuck table in the direction of arrow X1, a plurality of recesses 9 corresponding to the LED circuits 19 of the wafer 11 are formed on the back surface 21b of the transparent substrate 21 by ablation.

  According to the transparent substrate processing step using the mask 2, as shown in FIG. 4A, the recess 5B is formed at a position slightly shifted between the front surface 21a and the back surface 21b of the transparent substrate 21, and in the embodiment by the laser processing apparatus, As shown in FIG. 4B, a recess 9 is formed at a position slightly shifted between the front surface 21a and the back surface 21b of the transparent substrate 21.

  After performing the transparent substrate processing step, an integration step is performed in which the front surface 21a of the transparent substrate 21 is adhered to the back surface 11b of the wafer 11 to form the integrated wafer 25. In this integration step, as shown in FIG. 5A, the surface of the wafer 11 is formed on the surface 21a of the transparent substrate 21 in which a plurality of depressions 9 corresponding to the LED circuits 19 of the wafer 11 are formed on the front surface 21a and the back surface 21b. The back surface 11b is bonded with a transparent adhesive, and the wafer 11 and the transparent substrate 21 are integrated to form an integrated wafer 25 as shown in FIG. 5B.

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

  After carrying out the supporting process, the frame unit is put into a cutting device, and the dividing step of cutting the 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 into the spindle housing 12, and a cutting blade 14 attached to the tip of the spindle. Yes.

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

  The upper half of the cutting blade 14 is covered with a blade cover (wheel cover) 16, and the blade cover 16 is a pair of cooler nozzles (only one is shown) extending horizontally toward the back side and the near side of the cutting blade 14. 18 is arranged.

  In the dividing step, the integrated wafer 25 is sucked and held by 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 clamp (not shown).

  Then, while rotating the cutting blade 14 in the direction of arrow R at high speed, the cutting blade 14 is cut into the division line 17 of the wafer 11 until the tip of the cutting blade 14 reaches the dicing tape T. From the cooler nozzle 18 to the processing point of the cutting blade 14 and the wafer 11. The cutting groove 27 for cutting the wafer 11 and the transparent substrate 21 is formed along the division line 17 of the wafer 11 by processing and feeding the integrated wafer 25 in the direction of the arrow X1 while supplying the cutting fluid.

  While indexing and feeding the cutting unit 10 in the Y-axis direction, similar cutting grooves 27 are formed one after another along the planned dividing line 17 extending in the first direction. Next, after the chuck table 20 is rotated 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. In this state, the integrated wafer 25 is divided into light emitting diode chips 31 as shown in FIG.

  In the embodiment described above, the cutting device is used to divide the integrated wafer 25 into the individual light emitting diode chips 31. However, the laser beam having a wavelength that is transmissive to the wafer 11 and the transparent substrate 21 is divided. Irradiate the wafer 11 along the planned line 13 to form a plurality of modified layers in the thickness direction inside the wafer 11 and the transparent substrate 21, and then apply an external force to the integrated wafer 25 to modify the wafer. The integrated wafer 25 may be divided into individual light emitting diode chips 31 using the layers as division starting points.

  The light emitting diode chip 31 shown in FIG. 9 has a transparent member 21A in which a plurality of through holes 29 are formed on the back surface of an LED 13A having an LED circuit 19 on the front surface. Furthermore, dents 5, 5A, 5B or dents 9 are formed on the front and back surfaces of the transparent member 21A.

  Therefore, in the light emitting diode chip 31 shown in FIG. 9, since the depression is formed on the surface of the transparent member 21A, the surface area of the transparent member 21A increases. Further, a part of the light emitted from the LED circuit 19 of the light emitting diode chip 31 and incident on the transparent member 21A is refracted in the recessed portion and then enters the transparent member 21A, and a part of the light emitted from the transparent member 21A is The light is refracted into a plurality of portions at the depression and emitted.

  Accordingly, when the light is refracted and emitted from the transparent member 21A, the ratio of the light whose incident angle at the interface between the transparent member 21A and the air layer is greater than the critical angle is reduced, and the light emitted from the transparent member 21A is reduced. The amount increases, and the luminance of the light emitting diode chip 31 is improved.

2 Mask 5, 5A, 5B, 9 Recess 10 Cutting unit 11 Optical device wafer (wafer)
13 Sapphire substrate 14 Cutting blade 15 Laminate body layer 17 Divided line 19 LED circuit 21 Transparent substrate 21A Transparent member 25 Integrated wafer 27 Cutting groove 29 Through hole 31 Light emitting diode chip

Claims (5)

A method of manufacturing a light emitting diode chip,
Each of the regions 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 is divided into a plurality of division lines intersecting 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 transparent substrate processing step of forming a plurality of depressions corresponding to each LED circuit of the wafer on the front and back surfaces of the transparent substrate in which a plurality of through holes are formed over the entire surface;
After performing the transparent substrate processing step, an integration step of forming an integrated wafer by sticking the surface of the transparent substrate to the back surface of the wafer;
A dividing step of cutting the wafer along with the transparent substrate together with the transparent substrate to divide the integrated wafer into individual light emitting diode chips;
A method for producing 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 recess formed in the transparent substrate processing step is any one of a triangular shape, a square shape, and a circular shape.   2. The method of manufacturing a light-emitting diode chip according to claim 1, wherein in the transparent substrate processing step, the recess is formed by any one of etching, sandblasting, and laser.   The transparent substrate is formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin, and the transparent substrate is attached to the wafer using a transparent adhesive in the integration step. Manufacturing method of light emitting diode chip. A light emitting diode chip,
A light emitting diode having an LED circuit formed on the front surface, and a transparent member having a plurality of through holes attached to the back surface of the light emitting diode;
A light emitting diode chip in which depressions are formed on the front surface and the back surface of the transparent member.