TWI529032B - End surface grinding tool for substrate - Google Patents

Description

End face grinding device for substrate

The present invention relates to a polishing apparatus for polishing a cut end surface of a brittle substrate such as a glass substrate.

In the case of a brittle substrate such as glass, crystal, or ceramic, glass swarf may be generated at the cut end face, and breakage may occur from the microcrack. Therefore, it is desirable to suppress the swarf by finishing the end face into a mirror shape. Produced to increase the strength of the end face.

Conventionally, as shown in Fig. 6, it is conventional to use a grindstone 101 for polishing, and to mount the substrate 102 on the stage 103, and perform polishing processing once by pressing.

In this case, the amount of polishing is unstable and the number of steps is also large.

In recent years, in order to polish the end surface of such a hard brittle material into a mirror shape, it has been proposed to use a grinding wheel having a peripheral edge portion having elasticity.

A commercially available grinding wheel is filled with a resin in a fiber and dispersed in the resin.

Such a grinding wheel using an elastic material at the peripheral portion has a good adaptability when the outer peripheral surface of the grinding wheel is slidably contacted with the end surface of the substrate, and the mirror surface processing quality is stable.

However, since it is elastic, it is worn quickly, and a concave groove-shaped wear groove is formed along the contact surface of the substrate.

Therefore, when a predetermined number of substrates are subjected to the polishing process, the wear grooves become too deep and the rotational driving resistance of the polishing wheel becomes large, so that the polishing quality becomes unstable and defective products are likely to be generated.

In this case, it is conventionally known that the operator changes the contact position of the peripheral portion of the grinding wheel with the end surface of the substrate.

Thus, in order to adjust this, it is necessary to temporarily stop the processing line, which is one of the main reasons for the low productivity.

In Patent Documents 1 and 2, a technique for adjusting the cutting speed in accordance with the electric power value of the grindstone driving motor is disclosed, but the wear groove of the grinding wheel is not managed.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2004-122259

Patent Document 2: Japanese Patent Laid-Open No. Hei 7-171742

An object of the present invention is to provide an end surface polishing apparatus for a substrate having high continuous productivity in consideration of the amount of wear of the grinding wheel.

The end surface polishing apparatus for a substrate of the present invention includes: a polishing wheel made of an elastic material for a peripheral portion for polishing an end surface of the substrate; a rotational driving means of the polishing wheel; and a transfer control means. The rotation driving means includes a load current detecting means for detecting a load current flowing when the substrate is in contact with the end surface, and an appropriate determining means for the load current value. The transfer control means includes a transfer control means for the cutting direction of the end surface of the substrate, and a transfer control means for advancing the direction, and controls the transfer operation and the advancement direction of the grinding wheel in the cutting direction based on the appropriate determination means of the load current value. Transfer action.

The grinding wheel made of an elastic material at the peripheral portion means that the outer peripheral portion of the wheel for grinding the end surface of the substrate is at least an elastic material, and the elastic material contains abrasive grains.

The abrasive grains are not particularly limited, and examples thereof include diamond abrasive grains, cerium carbide abrasive grains, CBN (cubic boron nitride) abrasive grains, and cerium oxide abrasive grains.

Further, the elastic material may be a structure or a material having elasticity, and is not limited to filling the fiber with a resin.

An example of a method of controlling the transfer operation in the cutting direction of the grinding wheel and the transfer operation in the push direction based on the appropriate determination means of the load current value can be determined as a load during the polishing process of the substrate end face by an appropriate determination means of the load current value. When the current value exceeds the predetermined value, the subsequent substrate end surface processing is performed by the transfer control means in the above-described advancement direction by moving the polishing wheel at a predetermined pitch and starting the polishing process.

Further, in another method, when the appropriate determination means of the load current value determines that the load current value during the polishing process of the substrate end face is within a predetermined range, the transfer control means in the advance direction traverses the above at a predetermined speed Grinding the wheel while grinding.

Here, moving the grinding wheel only at a predetermined pitch means that the appropriate judgment means is determined by the load current value detected by the load current detecting means provided in the rotation driving means, so that the wear groove generated on the grinding wheel becomes deep so that it cannot be When it is used again, the conveying control means in the advancing direction moves the grinding wheel at least the thickness of the substrate in the advancing direction, and performs grinding processing on the new peripheral portion.

Therefore, in this case, the peripheral portion of the grinding wheel can form a wear groove at every predetermined interval.

On the other hand, in the method of traversing the grinding wheel at a predetermined speed while performing the polishing process, the appropriate determination means of the load current value confirms that the peripheral portion of the grinding wheel can be slidable in a state in which the end surface of the substrate is polished, and The method of traversing the grinding wheel in the conveying direction to grind the end surface of the substrate.

In this case, the peripheral portion of the grinding wheel is completely worn in the direction of advancement.

In the polishing apparatus of the present invention, the amount of wear generated in the peripheral portion of the grinding wheel is detected and considered in accordance with the load current value flowing into the rotation driving portion of the grinding wheel, and the conveying of the grinding wheel in the cutting direction and the conveying in the propulsion direction are controlled. Therefore, compared with the existing technique of temporarily stopping the production line to measure the depth of the wear groove and changing the sliding position of the grinding wheel, continuous processing is possible, productivity is improved, and the polishing quality is also stabilized.

First, the inventors of the present invention investigated the number of polishing processes of the glass substrate and the depth of the abrasion groove appearing in the peripheral edge portion of the polishing wheel using an elastic grinding wheel (manufactured by Sumitomo 3M Co., Ltd., trade name DLO wheel).

The result is shown in Fig. 5.

As the number of processing increases, the groove depth becomes deeper. When the grinding process is about 800, the groove depth becomes about 0.51 mm. At this time, the load current value flowing to the rotary driving portion of the grinding wheel and the grinding wheel do not generate the wear groove. The average increase is about 20%.

Further, when the number of grinding processes was increased to about 2,000, the depth of the abrading groove became 1.0 mm, and the load current value at this time was increased by about 40% on average compared with the case where no abrasion groove was produced.

It can be clearly seen from the results of the preliminary investigation that the depth of the wear groove of the grinding wheel can be predicted from the change in the load current value.

Next, an embodiment of the present invention will be described based on the drawings.

Fig. 3 schematically shows a configuration of a main portion of the polishing apparatus, and Fig. 4 shows an example of the conveyance control of the cutting direction of the grinding wheel 1 with respect to the substrate 2.

As shown in FIG. 3, the grinding wheel 1 is axially supported on a rotating shaft 31 connected to a driving portion having a rotational driving means and a conveying control means.

Although the illustration of the driving portion and the control portion thereof is omitted, the conveying control means for cutting the direction is controlled to slide in the end direction 21 of the substrate 2 at the rotation speed W ₁ of the grinding wheel 1, and to control the cutting direction. Transmission (X-axis control); and a transmission control means having a propulsion direction that controls movement in the propulsion direction with respect to the substrate 2 (Z-axis control).

Further, the drive unit includes load current detecting means for detecting a load current value generated by a load received by the frictional resistance when the grinding wheel 1 is slidably attached to the end surface 21 of the substrate 2.

In the embodiment shown in Fig. 3, the substrate 2 such as a glass substrate is clamped and held between the clamping portion 40a of the upper jig 40 controlled by the up-and-down movement and the clamping table 41a of the lower jig 41 while controlling the W ₂ direction. The rotation.

Further, as long as the substrate 2 can be held without being limited to the present embodiment, an adsorption means may be provided on the clamping table 41a to perform adsorption holding.

As shown in FIG. 4, the polishing apparatus of this embodiment rotates the control substrate 2, and controls the rotation center O of the grinding wheel, for example, using a polar coordinate system, and controls to sequentially move it to O ₁ to O ₃ so that the substrate 2 is One corner 2c corresponds to the side 2b and the other corner 2d. By rotating the substrate 2 one turn, the end faces of the entire circumference can be polished.

The polishing apparatus of the present invention is not limited to the embodiment, and may be an X-Y coordinate system control.

Next, a method of managing the abrasion of the grinding wheel 1 will be described.

Fig. 1 shows a first embodiment and shows only the cross section of the polishing wheel 1 and the vicinity of the end surface 21 of the substrate 2.

When the end face 21 of the substrate 2 is polished by the cutting means 1 (X-axis) by the control means (X-axis) of the cutting direction, the wear groove d is generated in the peripheral portion 1a made of an elastic material as the number of processes increases.

It can be seen from the preliminary investigation that as the wear groove d becomes deeper, the load current value of the rotary drive unit increases. Therefore, an appropriate judgment means for setting the load current value is used to determine the depth of the wear groove based on the increase amount of the load current value. The quality of the grinding is good or bad.

The appropriate determination means of the load current value has a calculation program, for example, it is possible to calculate the depth of the wear groove from the change in the load current value, and based on this, when determining the depth of the wear groove d as the limit, the transfer direction control means (Z The axis) moves only the pitch P in the Z-axis direction at the start of the next substrate polishing.

In the example shown in FIG. 1, the polishing wheel 1 only has a pitch P, and the state of the substrate 2a indicated by the imaginary line reaches the state of the substrate 2 indicated by the solid line, but may be a method of sequentially moving from the top to the bottom.

The size of the pitch P may be larger than the thickness of the substrate 2, and P is enlarged in FIG. 1 for the sake of clarity.

In the second embodiment shown in FIG. 2, while the sliding outer circumferential surface of the polishing wheel 1 and the peripheral edge portion 1a is slidably polished and the end surface 21 of the substrate 2 is slid, the grinding wheel 1 is in the advancing direction (Fig. 2). Up) Move control.

The transmission in the plunging direction is determined by the appropriate value of the load current value from the load current value, so that the polishing pressure is within a predetermined appropriate range.

1. . . Grinding wheel

1a. . . Peripheral part

2, 2a. . . Substrate

2b. . . Side

2c, 2d. . . Corner of the substrate

10. . . Transmission control means for cutting direction (X-axis)

20. . . Propulsion control means (Z axis)

twenty one. . . End face

30. . . Rotary drive

31. . . Rotary axis

40. . . Upper fixture

40a. . . Clamping section

41. . . Lower fixture

41a. . . Clamping table

101. . . Grindstone

102. . . Substrate

103. . . Mounting table

d. . . Wear groove

P. . . spacing

Fig. 1 shows an example of a grinding wheel control method of the polishing apparatus of the present invention.

Figure 2 illustrates an example of laterally controlling the grinding wheel.

Fig. 3 shows an example of the configuration of a main portion of the grinding apparatus.

Figure 4 shows an example of polar coordinate grinding control.

Fig. 5 shows the results of investigations on the number of polishing processes of the substrate and the depth of the wear groove.

Fig. 6 shows an example of a conventional grinding method.

1. . . Grinding wheel

1a. . . Peripheral part

2, 2a. . . Substrate

10. . . Transmission control means for cutting direction (X-axis)

20. . . Propulsion control means (Z axis)

twenty one. . . End face

30. . . Rotary drive

d. . . Wear groove

P. . . spacing

Claims (1)

An end surface polishing apparatus for a substrate, comprising: a grinding wheel, wherein a peripheral portion for polishing an end surface of the substrate is made of an elastic material; a rotary driving means of the grinding wheel; and a conveying control means; A load current detecting means for detecting a load current flowing when the peripheral end surface of the grinding wheel is in contact with the substrate, and an appropriate determining means for the load current value; the transfer control means having a cutting direction with respect to the end face of the substrate a control means and a transfer control means for advancing the direction, and detecting a polishing state in which the peripheral edge portion of the polishing wheel is slidably attached to the end surface of the substrate based on the appropriate determination means of the load current value, and controlling the transfer operation of the grinding wheel in the cutting direction In the transfer operation in the push direction, the appropriate determination means of the load current value determines that the wear groove generated along the end surface of the substrate at the peripheral portion of the polishing wheel is deeper, and the load current value at the time of polishing the substrate end surface exceeds a predetermined value. In the case, the subsequent substrate end face processing is the above advancement Transmission control means only to the predetermined thickness of the substrate than the pitch of movement of the grinding wheel, and grinding starts.