TWI772341B - Manufacturing method of light-emitting diode chip and light-emitting diode chip - Google Patents

Abstract

The subject of this invention is to provide the manufacturing method of the light emitting diode wafer which can obtain sufficient brightness, and a light emitting diode wafer. The solution of the present invention is a method of manufacturing a light-emitting diode wafer, which is characterized by preparing a laminate layer having a plurality of semiconductor layers including a light-emitting layer formed on a transparent substrate for crystal growth, and in the laminate layer. The wafer preparation process of the wafer on which the LED circuits are formed in the regions demarcated by a plurality of predetermined dividing lines that intersect each other on the surface, and the back surface of the wafer in which a plurality of recesses or grooves are formed corresponding to each LED circuit on the back side of the wafer. The processing process is the first transparent substrate bonding process of bonding the surface of the first transparent substrate to the back surface of the wafer to form the first integrated wafer. After the first transparent substrate bonding process is performed, the second transparent substrate is bonded. The surface is bonded to the back of the first transparent substrate to form the second transparent substrate bonding process of the second integrated wafer, and the wafer is cut along the predetermined dividing line together with the first and second transparent substrates A division process for dividing the second integrated wafer into individual light-emitting diode wafers.

Description

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

[0001] The present invention relates to a method for manufacturing a light-emitting diode wafer and a light-emitting diode wafer.

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, and a SiC substrate. Wafers on which a plurality of light-emitting devices such as LEDs (Light Emitting Diodes) are formed are formed in the area divided by the plurality of predetermined dividing lines, and are cut along the predetermined dividing lines to be divided into individual light-emitting device wafers, and the divided light-emitting device wafers are widely used. It is used in various electrical equipment such as mobile phones, computers, lighting equipment, etc. [0003] The light emitted from the light-emitting layer of the light-emitting device wafer is isotropic, so it is also irradiated to the inside of the substrate for crystal growth, and the light is also emitted from the back and side surfaces of the substrate. However, among the light rays irradiated inside the substrate, the incident angle at the interface with the air layer equal to or greater than the critical angle is totally reflected at the interface and enclosed in the substrate, and is not emitted from the substrate to the outside. The problem of lowering the brightness of the light-emitting device wafer. In order to solve this problem, Japanese Patent Application Laid-Open No. 2014-175354 describes that in order to suppress the situation in which the light emitted from the light-emitting layer is trapped inside the substrate, a transparent member is adhered to the back surface of the substrate to achieve light emission with improved brightness. Diodes (LEDs). [Prior Art Document] [Patent Document] [0005] [Patent Document 1] Japanese Patent Laid-Open No. 2014-175354

[Problems to be Solved by the Invention] [0006] However, in the light-emitting diode disclosed in Patent Document 1, although the brightness is slightly improved by adhering a transparent member to the back surface of the substrate, there is a problem that sufficient brightness cannot be obtained. question. [0007] The present invention has been made in view of this point, and an object thereof is to provide a method for producing a light-emitting diode chip and a light-emitting diode chip that can obtain sufficient brightness. [Means for Solving the Problems] [0008] According to the invention described in claim 1, there is provided a method for manufacturing a light-emitting diode wafer, characterized by comprising: a wafer preparation process for preparing a transparent material for crystal growth. A laminate layer including a plurality of semiconductor layers and a light-emitting layer is formed on the substrate, and the surface of the laminate layer is divided by a plurality of predetermined dividing lines that intersect each other to form LED circuit wafers respectively; wafer backside processing The process is to form a plurality of recesses or grooves corresponding to each LED circuit on the back of the wafer; the first transparent substrate bonding process is to bond the surface of the first transparent substrate to the back of the wafer to form a first integrated crystal. circle; the second transparent substrate bonding process, after the first transparent substrate bonding process is performed, the surface of the second transparent substrate is bonded to the back surface of the first transparent substrate to form a second integrated wafer; and the separation process and cutting the wafer together with the first and second transparent substrates along the predetermined dividing line, so as to divide the second integrated wafer into individual light-emitting diode chips. [0009] Ideally, the concave portion or groove formed in the wafer backside processing process is formed by any one of a cutter, etching, sandblasting, and laser. Ideally, the first and second transparent substrates are formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin; the first and second transparent substrate bonding processes are implemented using a transparent adhesive. . According to the invention recorded in claim 4, a kind of light-emitting diode wafer is provided, and it is characterized in that possessing: light-emitting diode, forms LED circuit on the surface, forms recessed part or groove on the back; The 1st transparent member, system The surface is adhered to the back surface of the light-emitting diode; and the second transparent member, the surface is adhered to the back surface of the first transparent member. [Effects of the Invention] [0012] The light-emitting diode chip of the present invention is formed on the back surface of the light-emitting diode with an LED circuit formed on the surface, and a recess or groove is formed on the back surface of the light-emitting diode, the surface of the first transparent member is bonded, and the 1 The back of the transparent member is bonded to the surface of the second transparent member, so the light is refracted complicatedly in the recesses or grooves and the first and second transparent members, and the light enclosed in the first and second transparent members is reduced. The amount of light emitted from the first and second transparent members increases, thereby improving the brightness of the light-emitting diode chip.

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

The optical device wafer 11 is formed by laminating an epitaxial layer (laminate layer) 15 of gallium nitride (GaN) or the like on a sapphire substrate 13 . The optical device wafer 11 has a front surface 11 a on which the epitaxial layer 15 is stacked, and a back surface 11 b where the sapphire substrate 13 is exposed.

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

The laminated body layer (epitaxy layer) 15 is formed by sequentially allowing electrons to become multiple An n-type semiconductor layer (for example, an n-type GaN layer) for a number of carriers, a semiconductor layer for a light-emitting layer (for example, an InGaN layer), and a p-type semiconductor layer (for example, a p-type GaN layer) for holes to be a majority carrier crystal growth to form.

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 laminated body layer 15, a plurality of LED circuits 19 are partitioned and formed by a plurality of predetermined dividing lines 17 formed in a lattice shape. The wafer 11 has a front surface 11 a on which the LED circuit 19 is formed, and a back surface 11 b where the sapphire substrate 13 is exposed.

According to the manufacturing method of the light-emitting diode wafer according to the embodiment of the present invention, first, a wafer preparation process for preparing the optical device wafer 11 as shown in FIG. 1 is performed. Furthermore, the wafer back surface processing process of forming a plurality of grooves 3 corresponding to the LED circuits 19 is performed on the back surface 11 b of the wafer 11 .

This wafer backside processing process is performed using, for example, a known cutting apparatus. As shown in FIG. 2(A) , 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 14 attached to the front end of the spindle.

The cutting edge of the cutting blade 14 is formed of, for example, a galvanized stone for fixing diamond abrasive grains by nickel electroplating, and the shape of the tip thereof is a triangle shape, a square shape, or a semicircle shape.

The roughly upper half of the cutting blade 14 is covered by a blade sleeve (wheel sleeve) 16, and a pair (only one shown in the figure) is arranged in the blade sleeve 16 to extend horizontally toward the distal side and the proximal side of the cutting blade 14 for cooling. Nozzle 18.

In the process of forming the back surface of the wafer in which the plurality of grooves 3 are formed on the back surface 11 b of the wafer 11 , the front surface 11 a of the wafer 11 is sucked and held by a chuck table of a cutting device (not shown). Then, by rotating the cutting blade 14 at a high speed in the direction of the arrow R while cutting into the back surface 11b of the wafer 11 to a predetermined depth, the wafer 11 held by the chuck table (not shown) is processed and fed in the direction of the arrow X1. The grooves 3 extended in the first direction are formed by cutting. While moving the wafer 11 to the direction orthogonal to the direction of the arrow X1, the back surface 11b of the wafer 11 is cut while the backside 11b of the wafer 11 is cut, as shown in FIG. 3 (A ), a plurality of grooves 3 extending in the first direction are successively formed. As shown in FIG. 3(A), the plurality of grooves 3 formed on the back surface 11b of the wafer 11 may be extended only in one direction, or as shown in FIG. The plural grooves 3 in the direction and the second direction orthogonal to the first direction may be formed on the back surface 11 b of the wafer 11 . The groove formed on the back surface 11b of the wafer 11 is a groove 3 having a triangular cross-section as shown in FIG. 2(B), or a groove 3A having a quadrangular cross-section as shown in FIG. 2(C), Alternatively, any of the grooves 3B having a semicircular cross-section as shown in FIG. 2(D) may be used. [0027] In the back surface 11b of the wafer 11, a plurality of recesses are formed corresponding to the LED circuits 19, instead of the back surface 11b of the wafer 11, the embodiment in which the plurality of grooves 3, 3A, 3B are formed by cutting may be acceptable. In this embodiment, as shown in FIG. 4(A) , a mask 2 having a plurality of holes 4 corresponding to the LED circuits 19 of the wafer 11 is used. [0028] As shown in FIG. 4(B), the holes 4 of the mask 2 are bonded to the back surface 11b of the wafer 11 corresponding to the LED circuits 19 of the wafer 11. Then, by wet etching or plasma etching, as shown in FIG. 4(C) on the back surface 11b of the wafer 11, a triangular-shaped recess 5 corresponding to the shape of the hole 4 of the mask 2 is formed. [0029] By changing the shape of the hole 4 of the mask 2 to a quadrangular shape or a circular shape, a quadrangular-shaped concave portion 5A as shown in FIG. As shown in E), the circular recess 5B may be formed on the back surface 11 b of the wafer 11 . As a modification of this embodiment, after the mask 2 is adhered to the backside 11b of the wafer 11, sandblasting is performed to form a triangle as shown in FIG. 4(C) on the backside 11b of the wafer 11 The concave portion 5 of the shape, the concave portion 5A of the quadrangular shape as shown in FIG. 4(D), or the concave portion 5B of the circular shape as shown in FIG. 4(E) may be used. [0031] Using a laser processing apparatus, a plurality of grooves or a plurality of recesses corresponding to the LED circuits 19 may be formed on the back surface 11b of the wafer 11. In the first embodiment by laser processing, as shown in FIG. 5(A) , by irradiating the back surface 11 b of the wafer 11 from the concentrator (laser head) 24 while irradiating the wafer 11 , the wafer 11 is absorbing A laser beam having a wavelength (for example, 266 nm) is processed and fed in the direction of arrow X1 while the chuck table not shown holding the wafer 11 is processed and fed, and the groove 7 extending in the first direction is formed on the wafer by ablation. 11 on the back side 11b. While moving the wafer 11 in a direction orthogonal to the direction of the arrow X1, the back surface 11b of the wafer 11 is subjected to ablation processing and successively formed by turning and feeding the wafer 11 with a pitch of the predetermined dividing line 17 of the wafer 11. The plural grooves 7 are elongated in the first direction. The cross-sectional shape of the groove 7 may be, for example, a semicircular shape as shown in FIG. 5(B), or may be other shapes. As an alternative embodiment, as shown in FIG. 5(C), a pulsed laser beam having an absorbing wavelength (eg, 266 nm) for the wafer 11 is intermittently irradiated from the concentrator 24 to the back surface of the wafer 11. 11b may form a plurality of recesses 9 corresponding to the LED circuits 19 . The shape of the concave portion 9 is generally a circular shape as shown in FIG. 5(D) corresponding to the spot shape of the laser beam. [0034] After the wafer back surface processing process is performed, as shown in FIG. 6(A), a first transparent substrate bonding process for bonding the front surface 21a of the first transparent substrate 21 to the back surface 11b of the wafer 11 is performed. FIG. 6(B) is a perspective view of the first integrated wafer 25 . [0035] The first transparent substrate 21 is formed of any one of transparent resin, optical glass, sapphire, and transparent ceramics. In the present embodiment, the first and second transparent substrates are formed of transparent resins such as polycarbonate and acrylic resin, which are more durable than optical glass. After the first transparent substrate bonding process is performed, as shown in FIG. 2 transparent substrate bonding process) to form the second integrated wafer 25A as shown in FIG. 7(B). The material of the second transparent substrate 21A is also the same as the material of the first transparent substrate 21 described above. In place of the above-mentioned first transparent substrate bonding process and second transparent substrate bonding process, after the surface of the second transparent substrate 21A is bonded to the back surface of the first transparent substrate 21 and integrated, the back surface of the wafer 11 is integrated. The 11b may be bonded to the surface 21a of the first transparent substrate 21 . After the second transparent substrate bonding process is performed, as shown in FIG. 8, the second transparent substrate 21A of the second integrated wafer 25A is bonded to the dicing tape T whose outer peripheral portion is bonded to the annular frame F. The frame unit is formed, and the annular frame F supports the supporting process of the second integrated wafer 25A through the dicing tape T. [0039] After the support process is carried out, a division process is carried out in which the frame unit is put into the cutting device, and the second integrated wafer 25A is cut by the cutting device to be divided into individual light-emitting diode wafers. This division process will be described with reference to FIG. 9 . [0040] This division process is carried out, for example, using a known cutting device. As shown in FIG. 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 14 attached to the front end of the spindle. [0041] The cutting edge of the cutting blade 14 is formed of, for example, an electroplating stone for fixing diamond abrasive grains by nickel electroplating, and the front end shape thereof is a triangular shape, a square shape, or a semicircular shape. A rough upper half of the cutting blade 14 is covered by a blade cover (wheel cover) 16, and a pair of horizontally extending toward the distal side and the proximal side of the cutting blade 14 is arranged on the blade cover 16 (only shown in Figure 1). 1) cooling nozzles 18. In the dividing process, the second integrated wafer 25A is sucked and held by the chuck table 20 of the cutting device across the dicing tape T of the frame unit, and the ring frame F is clamped and fixed by a clamp not shown. Then, while rotating the cutting blade 14 at a high speed in the direction of the arrow R, the front end of the cutting blade 14 reaches the dicing tape T and cuts into the predetermined dividing line 17 of the wafer 11, and moves from the cooling nozzle 18 to the cutting blade 14 and the wafer. The cutting fluid is supplied to the processing point 11, and the second integrated wafer 25A is processed and fed in the direction of the arrow X1, thereby forming the cut wafer 11 and the first and The cutting grooves 27 of the second transparent substrates 21 and 21A.

While turning and feeding the cutting unit 10 in the Y-axis direction, the same cutting grooves 27 are successively formed along the predetermined dividing line 17 extending in the first direction. Next, after rotating the chuck table 20 by 90°, the same cutting grooves 27 are formed along all the predetermined dividing lines 17 extending in the second direction orthogonal to the first direction, and the state shown in FIG. 10 is obtained. Thereby, the second integrated wafer 25A is divided into the light emitting diode chips 31 shown in FIG. 7 .

In the above-described embodiment, a cutting device is used to divide the second integrated wafer 25A into the respective light-emitting diode wafers 31. However, lasers having wavelengths that are transmissive to the wafer 11 and the transparent substrates 21 and 21A are used. The beam is irradiated to the wafer 11 along the predetermined dividing line 17 to form a plurality of modified layers in the thickness direction in the wafer 11 and the inside of the first transparent substrate 21 and the second transparent substrate 21A. 2. The second integrated wafer 25A may be divided into the respective light-emitting diode chips 31 by applying an external force to the second integrated wafer 25A with the modified layer as the starting point of division.

The light emitting diode chip 31 shown in FIG. 11 has the LED circuit 19 on the front surface, and the back surface of the LED 13A having the recess formed on the back surface is bonded to the first transparent member 21 ′ . Furthermore, the second transparent member 21A ' is bonded to the back surface of the first transparent member 21' .

Therefore, in the light-emitting diode wafer 31 shown in FIG. 11, in addition to the increase in the surface areas of the first and second transparent members 21 ' , 21A ' , the light rays penetrate the recesses 5 and the first and second transparent members 21 '. 21A ' is complicatedly refracted, the light enclosed in the transparent member will be reduced, the amount of light emitted from the transparent members 21 ' , 21A ' will increase, and the brightness of the light-emitting diode chip 31 will be improved.

2: Mask

3: Ditch

3A: Groove

3B: Groove

4: Holes

5: Recess

5A: Recess

5B: Recess

7: Ditch

9: Recess

10: Cutting unit

11: Optical device wafer (wafer)

11a: Surface

11b: Back

13: Sapphire substrate

14: Cutter

15: Laminate layers

16: Knife Set

17: Scheduled dividing line

19: LED circuit

21: The first transparent substrate

21´‧‧‧First transparent member 21a‧‧‧Front surface 21b‧‧‧Back surface 21A‧‧‧Second transparent substrate 21A´‧‧‧Second transparent member 25‧‧‧First integrated wafer 25A‧‧‧ 2nd integrated wafer 27‧‧‧cutting groove 31‧‧‧LED chip T‧‧‧dicing tape

[0013] [FIG. 1] A front side perspective view of an optical device wafer. [Fig. 2] Fig. 2(A) is a perspective view showing the backside processing process of the wafer by a cutting blade, and Figs. 2(B) to 2(D) are cross-sectional views showing the shape of the groove formed. [FIG. 3] FIG. 3(A) is a rear perspective view of a wafer having plural grooves formed on the back surface of the wafer and extending in the first direction, and FIG. 3(B) is a back surface of the wafer formed to extend in A perspective view of the back side of the wafer with plural grooves in the first direction and the second direction orthogonal to the first direction. [FIG. 4] FIG. 4(A) is a perspective view showing a state in which a mask is adhered to the backside of a wafer, and FIG. 4(B) is a perspective view showing a state in which a mask having a plurality of holes is adhered to the backside of the wafer, FIGS. 4(C) to 4(E) are partial perspective views of the wafer showing the shape of the concave portion formed on the back surface of the wafer. [Fig. 5] Fig. 5(A) is a perspective view showing how grooves are formed on the backside of the wafer by a laser beam, Fig. 5(B) is a partial cross-sectional view showing the groove shape of the wafer, and Fig. 5(C) It is a perspective view showing how a circular recess is formed on the back surface of the wafer by a laser beam, and FIG. 5(D) is a partial perspective view of the wafer showing the formed circular recess. [ Fig. 6] Fig. 6(A) is a perspective view showing a first transparent substrate bonding process in which the front surface of the first transparent substrate is bonded to the back surface of the wafer for integration, and Fig. 6(B) is a view of the first integrated wafer Stereogram.

[ Fig. 7] Fig. 7(A) is a perspective view showing a second transparent substrate bonding process in which the front surface of the second transparent substrate is bonded to the back surface of the first transparent substrate of the first integrated wafer and integrated, and Fig. 7(B) ) is a perspective view of the second integrated wafer.

[ Fig. 8] Fig. 8 is a perspective view showing a supporting process for supporting the second integrated wafer by a ring frame with a dicing tape interposed therebetween.

[ Fig. 9] Fig. 9 is a perspective view showing a division process of dividing the second integrated wafer into light-emitting diode wafers.

[ Fig. 10 ] A perspective view of the second integrated wafer after the division process is completed.

11 is a perspective view of a light-emitting diode wafer according to an embodiment of the present invention.

11‧‧‧Optical device wafer (wafer)

11a‧‧‧Surface

21‧‧‧First transparent substrate

21A‧‧‧Second transparent substrate

21a‧‧‧Surface

25A‧‧‧Second integrated wafer

Claims (4)

A method of manufacturing a light-emitting diode wafer, comprising: a wafer preparation process for preparing a laminate layer having a plurality of semiconductor layers including a light-emitting layer formed on a surface of a transparent substrate for crystal growth, and the layer is The surface of the built-up layer is divided into regions by a plurality of predetermined dividing lines that intersect each other, respectively forming wafers of LED circuits; the backside processing process of the wafers is related to the backside of the transparent substrate for crystal growth, corresponding to each LED circuit. A plurality of concave portions or grooves are formed, and the plurality of concave portions or grooves are separated from each other by a distance of a predetermined dividing line, and are formed on the back surface of the transparent substrate for crystal growth; the first transparent substrate bonding process is the first transparent substrate. The surface is bonded to the back of the transparent substrate for crystal growth to form a first integrated wafer; the second transparent substrate bonding process is to bond the surface of the second transparent substrate to the first transparent substrate bonding process after the first transparent substrate bonding process. The back surface of the first transparent substrate is formed to form a second integrated wafer; and the dividing process is to cut the wafer along the predetermined dividing line together with the first and second transparent substrates to form the second integrated wafer. The integrated wafer is divided into individual light-emitting diode chips; in the light-emitting diode obtained by the dividing process, the crystal growth substrate and the side surfaces of the first and second transparent substrates are coplanar. Manufacturing of light-emitting diode chips as described in item 1 of the scope of the patent application A manufacturing method, wherein, instead of the first transparent substrate bonding process and the second transparent substrate bonding process, after the surface of the second transparent substrate is bonded to the back surface of the first transparent substrate for integration, the back surface of the wafer is adhered to the surface of the first transparent substrate. The method for manufacturing a light-emitting diode wafer as described in item 1 of the scope of the application, wherein the first and second transparent substrates are formed of any one of transparent ceramics, optical glass, sapphire, and transparent resin; the first and second transparent substrates are formed of And this 2nd transparent substrate bonding process is implemented using a transparent adhesive agent. A light-emitting diode wafer is characterized by comprising: a light-emitting diode, an LED circuit is formed on the surface of a transparent substrate, a recess or a groove is formed on the backside of the transparent substrate; a first transparent member, the surface of which is adhered to the transparent substrate The back surface of the substrate; and the second transparent member, the surface is bonded to the back surface of the first transparent member; the transparent substrate is coplanar with the side surfaces of the first transparent member and the second transparent member.

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