TW201347019A - Sapphire wafer processing method - Google Patents

Abstract

The present invention provides a sapphire wafer processing method capable of cutting a sapphire wafer into chips by using a high speed rotating cutting knife. The present invention is a sapphire wafer processing method using a high speed rotating cutting knife to cut a sapphire wafer, which is characterized by including a holding step for holding the sapphire wafer on a holding surface of a clip platform, and a cutting step for cutting the sapphire wafer, which is held by the holding step, by the cutting knife rotating in high speed. The cutting knife is formed by combining molten glass with 30~70% porosity with diamond polishing grains with 10~50<mu>m particle size.

Description

Sapphire wafer processing method

The present invention relates to a method of processing a sapphire wafer that can be used to divide a sapphire wafer into a wafer using a high speed rotating cutter.

Background technique

Single crystal sapphire is used for various components due to its excellent heat resistance, mechanical stability, chemical stability, light penetration and the like. However, due to its very high Mohs hardness, its processing is very difficult.

Therefore, when a layer of epitaxial layer is deposited on the sapphire wafer and a plurality of LEDs are formed on the epitaxial layer, the segmentation of the sapphire wafer is selected to utilize the scribing and cutting of the diamond cutter, and the starting point of the laser beam is used. The cutting is formed and along the starting point of the division as its processing method.

A method of dividing a sapphire wafer on which a plurality of LEDs are formed into individual LEDs by a laser beam is known, and the first and second processing methods described below are known. In the first processing method, a laser beam having a wavelength (for example, 355 nm) having an absorptivity to a sapphire wafer is irradiated onto a region corresponding to a predetermined dividing line, and ablation processing is performed to form a starting point of the segmentation as a starting point of the segmentation. The trench is then given an external force to divide the sapphire wafer into individual LEDs.

The second processing method is to locate and focus the condensing point of the laser beam having a penetrating wavelength (for example, 1064 nm) on the sapphire wafer. The inside of the sapphire wafer corresponding to the alignment line is irradiated with the laser beam along the dividing line to form a modified layer inside the wafer, and then an external force is applied to divide the sapphire wafer into individual LEDs as the starting point of the segmentation.

In the method of using the sapphire wafer, in addition to the substrate of the LED, an optical component that exhibits its characteristics and is used as a polarizing film holding plate of a projector (see, for example, Japanese Laid-Open Patent Publication No. 2009-003232).

The holding plate of the polarizing film is not a large number of raw products like LEDs. The size of one wafer is relatively large, so the size of the chips generated during cutting is also large. Therefore, it is suitable for processing with a cutting device instead of investing expensive in the initial stage. Injection processing equipment processing.

Advanced technical literature Patent literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-319198

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-003232

Summary of invention

However, in sapphire wafer cutting by a cutter, it is conventional to use a resin-bonded or metal-bonded cutter to cut one line a plurality of times to divide the sapphire wafer into individual wafers. This is because the sapphire wafer has a high Mohs hardness, so it is very difficult to cut the corners for rapid cutting.

In view of the above, it is an object of the present invention to provide a method for processing a sapphire wafer into a wafer by a high speed rotating cutter.

According to the present invention, a method for processing a sapphire wafer can be provided, which comprises cutting a sapphire wafer by a high-speed rotating cutter, comprising: maintaining a step of holding the sapphire wafer on a holding surface of the clamping table; And the step of dividing the cutting blade that is rotated at a high speed into the sapphire wafer held by the holding step to divide the sapphire wafer, and the cutting blade is vitrified by a porosity of 30 to 70%. Combines diamond abrasive grains with a particle size of about 10 to 50 μm.

The method for processing a sapphire wafer according to the present invention uses a vitrified sintered glass having a porosity of about 30 to 70% to bond a diamond abrasive grain having a particle diameter of about 10 to 50 μm, compared to using a resin bond or a metal. Combined with the cutting of the cutting blade, the processing speed is about 1.3 to 2 times, and the fragmentation size can be improved to about 1/2 or 1/3. This is obtained by the cooling effect of the appropriate pores, the effect of the impurity discharge, and the appropriate holding force of the abrasive grains, and appropriate consumption.

2‧‧‧Cutting device

4‧‧‧Operator panel

6‧‧‧Display screen

8‧‧‧ Wafer

9‧‧‧匣lift

10‧‧‧ Moving in and out of the unit

11‧‧‧Sapphire wafer

12‧‧‧ temporary area

13‧‧‧Cutting trench

14‧‧‧ Positioning agency

15‧‧‧Defect

16‧‧‧Transport unit

18‧‧‧Clamping table

20‧‧‧ fixture

22‧‧‧ calibration unit

24‧‧‧ Shooting unit

26‧‧‧Shaft unit (cutting unit)

28‧‧‧ shaft

28a‧‧‧Bevel

28b‧‧‧Front-foot section

30‧‧‧Cutter

32‧‧‧Transport unit

34‧‧‧Rotary cleaning unit

36‧‧‧ shaft housing

38‧‧‧ male thread

40‧‧‧ knife holder

42‧‧‧seat

44‧‧‧Fixed flange

46‧‧‧ male thread

47‧‧‧Installation holes

48‧‧‧ Nuts

50‧‧‧Disassembly flange

52‧‧‧Fixed nuts

F‧‧‧ ring frame

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a cutting apparatus suitable for carrying out the processing method of the present invention.

Fig. 2 is an exploded perspective view showing a state in which the holder is fixed at the front end of the rotating shaft.

Fig. 3 is an exploded perspective view showing the state in which the spacer knife is attached to the holder.

Figure 4 is a partial cross-sectional side view showing the dividing step.

Fig. 5(A) is a photograph showing the result of cutting by the cutting blade of the vitrified sintering of the present invention, and Fig. 5(B) shows the combination of the conventional resin. A photograph of the cutting result of the cutting of the cutter.

Form for implementing the invention

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to Figure 1, a perspective view of a cutting device 2 suitable for practicing the processing method of the present invention is shown. The front side of the cutting device 2 is provided with an operation panel 4 for allowing an operator to input an instruction to the device such as a processing condition. A display screen such as a display such as a CRT is provided on the upper portion of the device, and an image displayed on the operator's guidance screen or an imaging unit to be described later can be displayed.

The sapphire wafer 11 to be cut by the cutting device 2 is placed in the wafer cassette 8 shown in FIG. 1 after being attached to the dicing tape T that has been mounted on the ring frame F. The wafer cassette 8 is placed on a lift 9 that can be moved up and down.

The loading/unloading unit 10 is disposed behind the wafer cassette 8, and the wafer 11 before cutting can be carried out from the wafer cassette 8 and the wafer after cutting can be carried into the wafer cassette 8.

Between the wafer cassette 8 and the carry-in/out unit 10, a temporary region 12 for temporarily placing the sapphire wafer 11 for loading and unloading is provided, and the temporary region 12 is provided with a positioning mechanism for positioning the sapphire wafer 11 at a certain position. 14.

A transport unit 16 is disposed in the vicinity of the temporary area 12, and the transport unit 16 has a sapphire wafer 11 that can suck and transport the sapphire wafer 11 and carry it out to the temporary area 12, and can be positioned by the transport unit 16 It is sucked and transported to the clamping table 18, and is attracted and held by the clamping table 18.

The clamping table 18 is configured to be movable back and forth in the X-axis direction by a rotatable and unillustrated machining feed mechanism, and the movement path of the clamping table 18 in the X-axis direction Above, a calibration unit 22 for detecting a cutting area of the sapphire wafer 11 is disposed. 20 is a jig capable of sandwiching the ring frame F.

The calibration unit 22 has an imaging unit 24 that captures the surface of the sapphire wafer 11, and based on the imaged image, the area to be cut can be detected by pattern contrast or the like. The image acquired by the imaging unit 24 is displayed on the display screen 6.

A rotating shaft unit (cutting unit) 26 is disposed on the left side of the calibration unit 22, and the sapphire wafer 11 held on the clamping table 18 can be subjected to cutting processing. The hinge unit 26 is integrally formed with the calibration unit 22, and the two are moved in the Y-axis direction and the Z-axis direction in conjunction with each other.

The spindle unit 26 is formed by attaching the cutter 30 to the front end of the rotatable shaft 28, and is movable in the Y-axis direction and the Z-axis direction. The cutter 30 is located on an extension line of the imaging unit 24 in the X-axis direction. The movement of the hinge unit 26 in the Y-axis direction can be achieved by a cutting feed mechanism (not shown).

34 is a spin cleaning unit that cleans the sapphire wafer 11 after the cutting process, and the sapphire wafer 11 after the cutting process is transported to the spin cleaning unit 34 by the transport unit 32, and is performed by the spin cleaning unit 34. Rotate and spin dry.

Referring to Fig. 2, an exploded perspective view showing the state in which the blade holder 40 is attached to the front end of the rotary shaft 28 is shown. A rotating shaft that can be rotationally driven by an electric motor (not shown) is rotatably accommodated in the rotating shaft case 36 of the rotating shaft unit 26. The rotating shaft 28 has a slope portion 28a and a front end small diameter portion 28b, and the distal end small diameter portion 28b is formed with a male screw 38.

40 is a seat, formed by the boss portion 42 and the boss portion 42 The fixing flange 44 is formed, and the boss portion 42 is formed with a male thread 46. Furthermore, the seat 40 has a mounting hole 47.

By inserting the front end small diameter portion 28b and the inclined surface portion 28a of the rotating shaft 28 into the mounting hole 47 and screwing the nut 48 to the male thread 46, the seat 40 can be attached to the front end of the rotating shaft 28 as shown in FIG. The diameter portion 28b.

Referring to Fig. 3, there is shown an exploded perspective view showing a state in which the spacer-shaped cutter 30 is attached to the holder 40 to which the tip end of the rotary shaft 28 is fixed. The shim-shaped cutter 30 is formed by combining vibrating sintering having a porosity of about 30 to 70% to bond diamond abrasive grains having a particle diameter of about 10 to 50 μm.

As described in Japanese Patent Publication No. Hei 6-24700, the vitrified sintered cutting blade 30 is produced by mixing ceramic or glass-based abrasive grains, organic abrasive grains, and diamond abrasive grains, and sintering at a predetermined temperature.

The cutting blade 30 is inserted into the boss portion 42 of the blade holder 40, the dismounting flange 50 is inserted into the boss portion 42, and the fixing nut 52 is screwed with the male screw 48, whereby the cutter 30 is fixed. The flange 44 and the dismounting flange 50 are attached to the rotating shaft 28 from both sides.

Referring to Fig. 4, there is shown a partial cross-sectional side view showing a state in which the sapphire wafer 11 is divided into individual wafers by a vitrified fusion cutter 30. Before the division step is performed, the surface of the sapphire wafer 11 is imaged by the imaging unit 24, and calibration is performed to detect a predetermined dividing line extending in the first direction.

After the calibration in the first direction is performed, the gantry 18 is rotated by 90 degrees, and the calibration is performed in the same manner to detect the planned dividing line extending in the second direction orthogonal to the first direction.

After the calibration is performed, the cutter is rotated and cut at a high speed in the A direction. The sapphire wafer 11 is inserted into the sapphire wafer 18 at a processing feed speed of, for example, 3 mm/s in the X-axis direction and the sapphire wafer 11 is completely cut. The cutting line is cut in the Y-axis direction and the dividing line extending in the first direction is gradually cut.

Next, the yoke wafer 18 is divided into individual wafers by cutting the nipple 18 by 90 degrees and cutting the grading of the sapphire wafer 11 in a gradual cutting direction in the Y-axis direction.

In the method for processing a sapphire wafer according to the present embodiment, the spacer-shaped cutter 30 is a vitrified fusion of diamond abrasive grains having a particle diameter of about 10 to 50 μm by a vitrification fusion of a porosity of about 30 to 70%. By knotting the knife, the processing speed can be improved by about 1.3 to 2 times, and the fragmentation size can be improved to about 1/2 to 1/3.

Referring to Figure 5, a comparison of the results of the cutting process using the vitrified fusion knives of the present invention with the results of the cutting process using conventional resin bonded knives is shown. Fig. 5(A) shows a photograph of the result of the cutting process using the vitrified fusion knives of the present invention, and Fig. 5(B) shows a photograph of the result of the cutting process using a conventional resin-bonding knives.

In the vitrified fusion knives, the result of cutting the sapphire wafer with a thickness of 0.7 mm by using the #400 diamond abrasive grain at a processing feed rate of 3 mm/s, and the resin bonding knife is The result of cutting the sapphire wafer having a thickness of 0.7 mm at a feed rate of 2 mm/s using a #240 diamond abrasive grain.

Here, the resin-bonding blade is a diamond abrasive grain of #240, because the fine abrasive grain like #400 cannot process the sapphire wafer.

In the conventional example shown in Fig. 5(B), a large notch as indicated by reference numeral 15 is generated. On the other hand, the processing method of the present invention using a vitrified fusion knives as shown in Fig. 5(A) hardly causes a missing angle.

15‧‧‧Angle

Claims (1)

A sapphire wafer processing method for cutting a sapphire wafer by a high-speed rotary cutter, comprising: maintaining a step of holding the sapphire wafer on a holding surface of the clamping table; and, dividing step The cutting blade that cuts at a high speed cuts into the sapphire wafer held by the holding step to divide the sapphire wafer, and the cutting blade combines the particle diameter with a vitrification fusion of a porosity of about 30 to 70%. Diamond abrasive grains of about 10~50μm.