JP2018148016A - Light emitting diode chip manufacturing method and light emitting diode chip - Google Patents

Abstract

Provided are a method of manufacturing a light emitting diode chip and a light emitting diode chip capable of obtaining sufficient luminance. A stacked layer includes a plurality of semiconductor layers including a light emitting layer formed on a transparent substrate for crystal growth. Each of the plurality of semiconductor layers is divided by a plurality of planned dividing lines intersecting each other on a surface of the stacked layer. A wafer preparation step of preparing a wafer in each of which a LED circuit 19 is formed in a region, and a corresponding LED circuit on at least one of the front and back surfaces of the first or second transparent substrate having a plurality of bubbles formed therein. A transparent substrate processing step of forming a plurality of grooves 23B, and attaching the front surface of the first transparent substrate to the back surface of the wafer and attaching the front surface of the second transparent substrate to the back surface of the first transparent substrate. A step of attaching a transparent substrate to form an integrated wafer by dividing the integrated wafer into individual light emitting diode chips 31 by cutting the wafer along with the first and second transparent substrates along a line to be divided. The manufacturing method comprising the steps, a. [Selection diagram] FIG.

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 of the substrate, and a first transparent substrate having a plurality of bubbles formed therein or the inside A transparent substrate processing step of forming a plurality of grooves corresponding to the LED circuits on the front surface or the back surface of at least one of the second transparent substrates in which a plurality of bubbles are formed, and after performing the transparent substrate processing step Affixing the surface of the first transparent substrate to the back surface of the wafer and attaching the surface of the second transparent substrate to the back surface of the first transparent substrate to form an integrated wafer Steps, and A division step of dividing the integrated wafer into individual light emitting diode chips by cutting the wafer together with the first and second transparent substrates along the division line after performing the bright substrate attaching step; A method for manufacturing a light-emitting diode chip is provided.

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

  The first and second transparent substrates are formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin, and the first transparent substrate is bonded to the wafer with a transparent adhesive in the transparent substrate attaching step. Then, the second transparent substrate is bonded to the first transparent substrate with a transparent adhesive.

  According to invention of Claim 5, it is a light emitting diode chip | tip, Comprising: The light emitting diode by which the LED circuit was formed in the surface, and several bubble was formed in the inside stuck on the back surface of this light emitting diode. A transparent member, and a second transparent member having a plurality of bubbles formed inside attached to the back surface of the first transparent member, the first transparent member or the second transparent member There is provided a light-emitting diode chip in which a groove is formed on at least one of the front surface and the back surface.

  In the light emitting diode chip of the present invention, light is refracted in a complicated manner by a plurality of bubbles and grooves formed in at least two layers of transparent members, and the light confined in the first and second transparent members is reduced. The amount of light emitted from the first and second transparent members 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 transparent substrate processing step, and FIGS. 2B to 2D are cross-sectional views showing the formed groove shape. FIG. 3A is a perspective view showing a transparent substrate adhering process in which a first transparent substrate having a plurality of grooves extending in the first direction on the surface is adhered to the back surface of the wafer to form a first integrated wafer. FIG. 3 and FIG. 3B are perspective views of the first integrated wafer. The transparent substrate sticking process which sticks and integrates the 1st transparent substrate which has a plurality of slots prolonged on the surface in the 1st direction and the 2nd direction orthogonal to the 1st direction on the back of a wafer is shown. It is a perspective view. FIG. 5A is a perspective view showing a state in which the surface of the second transparent substrate is adhered to the back surface of the first integrated wafer to form the second integrated wafer, and FIG. 5B is the second integrated wafer. It is a perspective view of a wafer. It is a perspective view which shows the support process which supports a 2nd integrated wafer with an annular frame via a dicing tape. It is a perspective view which shows the division | segmentation 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. FIG. 9A to FIG. 9D are perspective views of light emitting diode chips 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. Also, a first transparent substrate 21 having a plurality of bubbles formed therein and a second transparent substrate 21A having a plurality of bubbles 29A formed therein are prepared as shown in FIGS. A transparent substrate preparation step is performed.

  After performing the wafer and transparent substrate preparation step, the second transparent substrate 21 </ b> A that is adhered to the front surface or the rear surface of the first transparent substrate 21 that is adhered to the rear surface 11 b of the wafer 11 or the rear surface of the first transparent substrate 21. A transparent substrate processing step for forming a plurality of grooves corresponding to the LED circuit 19 on the front surface or the back surface of the substrate is performed. This transparent substrate processing step is performed using, for example, 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 into the spindle housing 12, and a cutting blade 14 attached to the tip of the spindle. Is included.

  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 transparent substrate processing step of forming the plurality of grooves 23 on the surface 21a of the first transparent substrate 21, the first transparent substrate 21 is sucked and held by a chuck table of a cutting device (not shown). Then, a predetermined depth is cut into the surface 21a of the first transparent substrate 21 while rotating the cutting blade 14 at a high speed in the direction of arrow R, and the first transparent substrate 21 held on a chuck table (not shown) is processed and fed in the direction of arrow X1. Thus, 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 the first transparent substrate 21 is indexed and fed in the direction orthogonal to the arrow X1 direction by the pitch of the division lines 17 of the wafer 11. 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 be extended only in one direction, or as shown in FIG. A plurality of grooves 23 extending in the first direction and the 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. 2B, or a groove 23A having a square cross section as shown in FIG. Any of the grooves 23B having a semicircular cross section as shown in FIG.

  The first transparent substrate 21 and the second transparent substrate 21A are formed of any one of transparent resin, optical glass, sapphire, and transparent ceramics. In the present embodiment, the first transparent substrate 21 and the second transparent substrate 21A are formed from a transparent resin such as polycarbonate and acrylic that are more durable than optical glass. As a method for forming the groove, sand blasting, etching, or laser may be used.

  In the embodiment described above, a plurality of grooves 23, 23 </ b> A, 23 </ b> B are formed on the front surface 21 a of the first transparent substrate 21. Instead of this embodiment, a plurality of grooves are formed on the back surface 21 b of the first transparent substrate 21. The grooves 23, 23A, and 23B may be formed.

  Alternatively, a plurality of grooves 23 corresponding to each LED circuit 19 of the wafer 11 are formed on the front surface 21a or the back surface 21b of the second transparent substrate 21A without performing any processing on the front surface and the back surface of the first transparent substrate 21. 23A and 23B may be formed.

  After performing the transparent substrate processing step, the front surface 21a of the first transparent substrate 21 is adhered to the rear surface 11b of the wafer 11, and the front surface 21a of the second transparent substrate 21A is adhered to the rear surface 21b of the first transparent substrate 21. The transparent substrate sticking process to wear is implemented.

  In this transparent substrate attaching step, as shown in FIG. 3A, the back surface of the wafer 11 is formed on the surface of the first transparent substrate 21 in which a plurality of grooves 23 extending in the first direction are formed on the surface 21a. 11b is bonded 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.

  As an alternative embodiment, as shown in FIG. 4, the first surface 21 a of the first transparent substrate 21 has a plurality of grooves 23 extending in a first direction and a second direction orthogonal to the first direction. The wafer 11 and the first transparent substrate 21 may be integrated by bonding the back surface 11b of the wafer 11 to the front surface 21a of the transparent substrate 21 with a transparent adhesive. Here, the pitch of the grooves 23 formed on the surface 21 a of the first transparent substrate 21 corresponds to the pitch of the division lines 17 of the wafer 11.

  Next, as shown in FIG. 5A, the surface 21a of the second transparent substrate 21A in which a plurality of bubbles 29A are formed is pasted on the back surface 21b of the first transparent substrate 21 of the first integrated wafer 25. The second integrated wafer 25A as shown in FIG. 5B is formed.

  This transparent substrate sticking process is not limited to the order mentioned above, but after sticking the surface 21a of the 2nd transparent substrate 21A to the back 21b of the 1st transparent substrate 21, the 1st transparent substrate 21 The front surface 21a may be adhered to the back surface 11b of the wafer 11 to form the second integrated wafer 25A.

  After carrying out the transparent substrate attaching step, as shown in FIG. 6, the second transparent substrate 21A of the second integrated wafer 25A is attached to a dicing tape T whose outer peripheral portion is attached 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 integrated wafer 25 with the cutting device and dividing it into individual light emitting diode chips is carried out. This dividing step will be described with reference to FIG.

  In the dividing step, the second integrated wafer 25A 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 second integrated wafer 25A is processed and fed in the direction of the arrow X1 while supplying the cutting fluid toward the wafer 11, and the wafer 11 and the first and second transparent substrates 21 and 21A along the scheduled division line 17 of the wafer 11. A cutting groove 27 for cutting is formed.

  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. By setting the state, the second integrated wafer 25A 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 second integrated wafer 25A into the individual light emitting diode chips 31, but the wavelength of the wavelength having transparency to the wafer 11 and the transparent substrates 21 and 21A. The wafer 11 is irradiated with a laser beam along the division line 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. 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 a division starting point.

  The light emitting diode chip 31 shown in FIG. 9A has a first transparent member 21 ′ in which a plurality of bubbles 29 are formed inside attached to the back surface of the LED 13 </ b> A having the LED circuit 19 on the front surface. A groove 23B is formed on the surface of the first transparent member 21 '. Further, a second transparent member 21A ′ having a plurality of bubbles formed therein is adhered to the back surface of the first transparent member 21 ′.

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

  In the light emitting diode chip 31B shown in FIG. 9C, a first transparent member 21 ′ having a plurality of bubbles formed therein is attached to the back surface of the LED 13A having the LED circuit 19 on the front surface. Further, a second transparent member 21A ′ is adhered to the back surface of the first transparent member 21 ′. A groove 23B is formed on the surface of the second transparent member 21A ′.

  In a light emitting diode chip 31C shown in FIG. 9D, a first transparent member 21 ′ having a plurality of bubbles formed therein is attached to the back surface of an LED 13A having an LED circuit 19 on the front surface. Furthermore, the surface of the second transparent member 21A ′ is adhered to the back surface of the first transparent member 21 ′. A groove 23B is formed on the back surface of the second transparent member 21A ′.

  Therefore, in the light emitting diode chip 31 shown in FIG. 9A, the groove 23B is formed on the surface of the first transparent member 21 ′, so that the surface area of the first transparent member 21 ′ increases. Furthermore, a part of the light emitted from the LED circuit 19 of the light emitting diode chip 31 and incident on the first transparent member 21 ′ is refracted by the groove 23 B portion and then enters the first transparent member 21 ′.

  Therefore, when light is refracted to the outside from the first transparent member 21 ′ and the second transparent member 21A ′, the light is emitted at the interface between the first and second transparent members 21 ′ and 21A ′ and the air layer. The proportion of light whose incident angle is greater than or equal to the critical angle is reduced, the amount of light emitted from the first and second transparent members 21 ′ and 21 A ′ is increased, and the luminance of the light emitting diode chip 31 is improved.

  The light emitting diode chips 31A, 31B, and 31C shown in FIGS. 9B to 9D also have the same effects as the light emitting diode chip 31 shown in FIG.

10 Cutting unit 11 Optical device wafer (wafer)
13 Sapphire substrate 14 Cutting blade 15 Laminate layer 17 Scheduled division line 19 LED circuit 21 1st transparent substrate 21 ′ 1st transparent member 21A 2nd transparent substrate 21A ′ 2nd transparent members 23, 23A, 23B Groove 25 First integrated wafer 25A Second integrated wafer 27 Cutting groove 29 Air bubbles 31, 31A, 31B, 31C 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 plurality of grooves corresponding to the LED circuit are formed on the front surface or the back surface of at least one of the first transparent substrate having a plurality of bubbles formed therein or the second transparent substrate having a plurality of bubbles formed therein. Transparent substrate processing step to
After carrying out the transparent substrate processing step, the surface of the first transparent substrate is adhered to the back surface of the wafer and the surface of the second transparent substrate is adhered to the back surface of the first transparent substrate. A transparent substrate pasting process for forming a modified wafer;
A dividing step of dividing the integrated wafer into individual light-emitting diode chips by cutting the wafer together with the first and second transparent substrates along the division line after the transparent substrate attaching step; ,
A method for producing a light-emitting diode chip, comprising:   2. The method of 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.   2. The method of manufacturing a light-emitting diode chip according to claim 1, wherein in the transparent substrate processing step, the groove is formed by any one of a cutting blade, etching, sand blast, and laser.   The first and second transparent substrates are formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin, and in the transparent substrate pasting process, the first transparent substrate is a wafer using a transparent adhesive. The method for manufacturing a light-emitting diode chip according to claim 1, wherein the second transparent substrate is bonded to 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 in which a plurality of bubbles are formed in the inside attached to the back surface of the light emitting diode;
A second transparent member in which a plurality of bubbles are formed in the inside attached to the back surface of the first transparent member;
With
A light emitting diode chip in which a groove is formed on the front surface or the back surface of at least one of the first transparent member and the second transparent member.