Blade detection unit and cutting device equipped with same

Abstract

To propose novel technique for enabling detection of an accurate lower end position of a cutting blade by protecting a blade detection unit.SOLUTION: A blade detection unit 20 is provided which includes a light emitting unit 23, and a light receiving unit 24 which faces the light emitting unit 23 and receives light from the light emitting unit 23, and which detects the distal end of a cutting blade 51 when the cutting blade 51 is positioned between the light emitting unit 23 and the light receiving unit 24. The blade detection unit 20 includes: a protective member 32 which is inserted into between a light emitting surface 23a of the light emitting unit 23 and a light receiving surface 23b of the light receiving unit 24, and is adhered to each of the light emitting surface 23a and the light receiving surface 23b; and a positioning unit 27 positioning the protective member 32 at a protection position where the protective member 32 is inserted into between the light emitting unit 23 and the light receiving unit 24, and a retraction position where the protective member 32 retracts from the protection position, respectively.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a blade detection unit and a cutting device equipped with the same, and more particularly to a mechanism for protecting the blade detection unit. [Background technology]

[0002] Conventionally, as disclosed in Patent Documents 1 and 2, for example, cutting devices equipped with cutting blades for cutting semiconductor wafers have been known. The cutting blade wears as cutting is performed, and the position of the tip of the cutting edge relative to the holding surface of the holding table changes. When the tip position of the cutting edge changes, the depth of cut into the workpiece also changes. For this reason, as disclosed in Patent Documents 1 and 2, it is known to detect the tip position of the cutting edge using a blade detection unit (cutting blade detection mechanism) and correct the depth of cut.

[0003] The blade detection unit disclosed in Patent Document 1 has an emitting section including an emitting surface and a light receiving section including a light receiving surface facing the emitting surface, and detects the lower end position (tip position) of the cutting blade's cutting edge relative to the holding surface of the holding table based on the height position of the cutting blade when light from the emitting surface is blocked by the cutting blade inserted between the emitting section and the light receiving section.

[0004] Therefore, if foreign matter such as cutting chips adheres to the light-emitting surface or light-receiving surface, there is a risk that the position of the bottom end of the cutting blade tip will be erroneously detected. Therefore, as disclosed in Patent Document 2, a configuration has been proposed in which a cover is provided to cover the light-emitting unit and the light-receiving unit. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-298001 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-211354 Summary of the Invention [Problem to be solved by the invention]

[0006] During cutting, cutting water is supplied to the cutting blade, but cutting chips produced by cutting get mixed into the cutting water, producing contaminated water, which becomes mist and floats as the cutting blade rotates.

[0007] Therefore, even if the blade detection unit is covered with a cover, there is a concern that mist may enter the cover through gaps and adhere to the light-emitting surface or light-receiving surface as foreign matter.

[0008] If foreign matter adheres to the light-emitting surface or the light-receiving surface in this way, the accurate position of the lower end of the cutting blade may not be detected, which may result in defective processing.

[0009] In view of the above problems, the present invention proposes a novel technique for protecting the blade detection unit, thereby enabling the accurate detection of the lower end position of the cutting blade. [Means for solving the problem]

[0010] The problem to be solved by the present invention is as described above, and the means for solving this problem will now be described.

[0011] According to one aspect of the present invention, a blade detection unit has an emitting unit and a light receiving unit facing the emitting unit and receiving light from the emitting unit, and detects the tip of the cutting blade when the cutting blade is positioned between the emitting unit and the light receiving unit, the blade detection unit having a protective member inserted between the emitting surface of the emitting unit and the light receiving surface of the light receiving unit and in close contact with the emitting surface and the light receiving surface, respectively, and a positioning unit that positions the protective member at a protective position inserted between the emitting unit and the light receiving unit, and at a retracted position retracted from the protective position.

[0012] According to another aspect of the present invention, the protective member is made of a material that is compressively deformable and can be cut by the cutting blade.

[0013] According to one aspect of the present invention, a cutting device is provided that includes a blade detection unit, a holding table that holds a workpiece, and a cutting unit that has a cutting blade that cuts the workpiece held by the holding table. [Effects of the Invention]

[0014] According to one form of the present invention, when the position of the cutting edge of the cutting blade cannot be detected, the protective member is positioned in the protective position and comes into close contact with the light-emitting surface and the light-receiving surface, thereby preventing mist containing cutting debris from adhering to the light-emitting surface and the light-receiving surface as foreign matter.

[0015] Furthermore, even if, due to some obstacle, the protective member does not move to the retracted position but is positioned in the protective position, causing the cutting blade to descend, the cutting blade can be made to cut into the protective member, thereby preventing damage to the cutting blade. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 10 is a diagram showing an example of a cutting device equipped with a blade detection unit. [Figure 2] 1A is a diagram illustrating a state in which the protection mechanism is positioned at the retracted position, and FIG. 1B is a diagram illustrating a state in which the protection mechanism is positioned at the protection position. [Figure 3] FIG. 1 is a schematic diagram of the blade detection unit seen from above. DETAILED DESCRIPTION OF THE INVENTION

[0017] An embodiment of the present invention will now be described with reference to the drawings. FIG. 1 is a diagram showing an overview of a cutting device 1 equipped with a blade detection unit 20 according to the present invention.

[0018] 1, the cutting device 1 dices a plate-shaped workpiece W such as a semiconductor wafer using a cutting unit 5. The cutting device 1 includes a holding table 2, an imaging unit 3, a movement mechanism (a Y-axis movement mechanism 41, a Z-axis movement mechanism 42), the cutting unit 5, and a blade detection unit 20. The workpiece W may be an optical device wafer, a plate-shaped inorganic material substrate, a plate-shaped ductile material, or the like.

[0019] The holding table 2 is disk-shaped, and a horizontal holding surface is formed on its upper surface. The holding surface is made of a porous material, and is connected to a suction source (not shown) to generate negative pressure, thereby suction-holding the workpiece W on the holding surface.

[0020] The holding table 2 is moved in the X-axis direction by an X-axis movement mechanism (not shown) provided in the base 6, and feeds the workpiece W to the cutting unit 5 for processing.

[0021] A plurality of clamps 7 are provided around the holding table 2 to clamp an annular frame F to which a workpiece W is fixed. The workpiece W is fixed to the annular frame F via a tape T and is handled as a wafer unit U.

[0022] The periphery of the holding table 2 is covered with a cover plate 8, and a blade detection unit 20 for detecting the lower end position of the cutting edge of the cutting blade of the cutting unit 5 is provided on the cover plate 8.

[0023] The cutting unit 5 is configured to have a spindle 52 driven by a motor (not shown) and a cutting blade 51 fixed to the tip of the spindle 52. The cutting blade 51 is, for example, a circular grinding stone in which abrasive grains made of artificial diamond are held by a bond material.

[0024] The cutting unit 5 is moved in the Y-axis direction and the Z-axis direction by a Y-axis movement mechanism 41 and a Z-axis movement mechanism 42. The Y-axis movement mechanism 41 supports the cutting unit 5 so that it can move relatively to the base 6 in the Y-axis direction (corresponding to the indexing feed direction). The Z-axis movement mechanism 42 supports the cutting unit 5 so that it can move relatively to the base 6 in the Z-axis direction (corresponding to the cutting feed direction).

[0025] The Y-axis moving mechanism 41 is configured to include a pair of guide rails 41a, 41a attached to the front surface of the gate-shaped column 9 and extending parallel to the Y-axis direction, a ball screw 41b arranged between the guide rails 41a, 41a, and a motor 41c fixed to one end of the ball screw 41b. The ball screw 41b is connected to the Y-axis moving plate 4Y via a nut (not shown), and by rotating the ball screw 41b with the motor 41, the Y-axis moving plate 4Y moves in the Y-axis direction along the guide rails 41a, 41a.

[0026] The Z-axis movement mechanism 42 includes a pair of guide rails 42a, 42a attached to the front surface of the Y-axis movement plate 4Y and extending parallel to the Z-axis direction, a ball screw 42b disposed between the guide rails 42a, 42a, and a motor 42c fixed to one end of the ball screw 42b. The ball screw 42b is connected to the Z-axis movement plate 4Z via a nut (not shown), and the Z-axis movement plate 4Z moves in the Z-axis direction along the guide rails 42a by rotating the ball screw 42b with the motor 42. The imaging unit 3 and the cutting unit 5 are fixed to the lower end of the Z-axis movement plate 4Z.

[0027] The imaging unit 3 captures an image of the planned dividing line (street) of the workpiece W before cutting in order to adjust the alignment of the cutting unit 5 with the street. The imaging unit 3 is, for example, a camera using a CCD (Charge Coupled Device) image sensor.

[0028] Next, the blade detection unit 20 shown in Figures 2(A) and (B) will be described. The blade detection unit 20 is also called a setup sensor, and is used to detect the lower end position of the cutting edge of the cutting blade 51, i.e., the position in the Z direction, at a predetermined timing or at any timing when necessary, and to adjust the cutting height position in response to wear of the cutting blade 51 and set it up.

[0029] The blade detection unit 20 has a rectangular parallelepiped detection base 21. On the top surface of the detection base 21, an approximately L-shaped optical sensor 22 having a vertical wall portion 22z and a horizontal plate portion 22h is fixed.

[0030] A blade insertion groove 22a penetrating in the X-axis direction is formed in the vertical wall portion 22z of the optical sensor 22. A light emitting surface 23a of the light emitting unit 23 and a light receiving surface 24a of the light receiving unit 24 are arranged on the opposing surfaces of the wall portions 22b on both sides of the blade insertion groove 22a, and the light irradiated from the light emitting unit 23 is detected by the light receiving unit 24.

[0031] Nozzles 25 and 26 are provided on the horizontal plate 22h of the optical sensor 22 to supply air or a cleaning liquid such as pure water to the light-emitting surface 23a of the light-emitting unit 23 and the light-receiving surface 24a of the light-receiving unit 24. This allows cleaning liquid to be supplied from the nozzles 25 and 26 at a predetermined timing, and then air is blown to remove foreign matter adhering to the light-emitting surface 23a and the light-receiving surface 24a, thereby improving the accuracy of cutting blade detection.

[0032] A protection mechanism 30 is provided on one side of the detection table 21 in the X-axis direction, which is movable in the X-axis direction relative to the detection table 21. The protection mechanism 30 is connected to the detection table 21 via two rods 31, and moves in the X-axis direction by advancing and retracting the rods 31 using a positioning unit 27 provided inside the detection table 21. The positioning unit 27 is composed of a direct-acting air cylinder or an electromagnetic actuator that moves the rods 31 forward and backward. This makes it possible to achieve a configuration that is less prone to malfunctions and failures than, for example, a configuration in which the detection table 21 is protected by driving a rotating cover.

[0033] Fig. 2(A) shows a state in which the protection mechanism 30 is moved to the retracted position when detecting the cutting blade 51. Fig. 2(B) shows a state in which the protection mechanism 30 is moved to the protection position when not detecting the cutting blade 51. In this way, the protection mechanism 30 moves between the retracted position and the protection position.

[0034] The protection mechanism 30 has a rectangular parallelepiped main body 30a, and a protection member 32 is provided so as to protrude from the main body 30a toward the detection base 21. When the protection mechanism 30 is in the protection position, the protection member 32 is inserted between the light-emitting surface 23a and the light-receiving surface 24a in the blade insertion groove 22a.

[0035] The protective member 32 is made of a material that is compressively deformable and can be cut by the cutting blade 51, and can be made of, for example, sponge, rubber, or a resin material such as urethane.

[0036] Also, as shown in Figure 3, the protective member 32 has a width 32w that is slightly wider than the groove width 22w (width in the Y-axis direction) of the blade insertion groove 22a, and is therefore inserted between the light-emitting surface 23a and the light-receiving surface 24a in a slightly compressed state.

[0037] By inserting the protective member 32 into the blade insertion groove 22a in a compressed state, the side surfaces of the protective member 32 come into close contact with the light-emitting surface 23a and the light-receiving surface 24a, thereby protecting the light-emitting surface 23a and the light-receiving surface 24a. This makes it possible to prevent cutting fluid supplied to the cutting blade 51, cutting chips generated by cutting, and even mist containing cutting chips from adhering as foreign matter to the light-emitting surface 23a and the light-receiving surface 24a during cutting.

[0038] Furthermore, as shown in FIG. 3, when the protective member 32 is inserted into or pulled out of the blade insertion groove 22a, the light-emitting surface 23a and the light-receiving surface 24a can be cleaned by wiping them with the side surfaces 32a, 32a on both sides of the protective member 32.

[0039] 2(A) and 2(B), an attachment groove 30b that opens upward is formed in the upper part of the main body 30a of the protection mechanism 30, and the rear end side of the protection member 32 is inserted into the attachment groove 30b, thereby fixing the protection member 32 to the main body 30a. The front end side of the protection member 32 protrudes from the main body 30a and is inserted into the blade insertion groove 22a.

[0040] Here, the attachment groove 30b formed in the main body 30a of the protection mechanism 30 is positioned on an extension of the blade insertion groove 22a in the X-axis direction and is provided so as to penetrate in the X-axis direction, so that only the protection member 32 is exposed upward on the extension of the blade insertion groove 22a in the X-axis direction.

[0041] 2(B), when the position of the cutting edge of the cutting blade 51 is not being detected, the protection mechanism 30 is positioned in the protection position, and the protection member 32 is inserted into the blade insertion groove 22a to protect the light-emitting surface 23a and the light-receiving surface 24a, preventing mist containing cutting debris from adhering to the light-emitting surface 23a and the light-receiving surface 24a as foreign matter. Furthermore, when the protection member 32 moves, the light-emitting surface 23a and the light-receiving surface 24a are cleaned. In this way, the lower end position (height position) of the cutting blade 51 can be detected with high accuracy.

[0042] On the other hand, as shown in FIG. 2(A), when detecting the position of the cutting edge of the cutting blade 51, the protective member 32 of the protection mechanism 30 is moved away from the blade insertion groove 22a to a retracted position, thereby opening the blade insertion groove 22a. Then, the cutting blade 51 is lowered to enter the blade insertion groove 22a. When the cutting edge of the cutting blade 51 is positioned between the light-emitting unit 23 and the light-receiving unit 24 and the light emitted from the light-emitting unit 23 is blocked by the cutting blade 51, the amount of light received by the light-receiving unit 24 changes. By detecting this change, the lower end position (height position) of the cutting edge of the cutting blade 51 is detected.

[0043] Here, for example, as shown in Figure 2(B), even if, due to some obstacle, the protection mechanism 30 is positioned in the protection position instead of moving to the retracted position and the cutting blade 51 drops down, the protection member 32 will be present in the blade insertion groove 22a, and the cutting blade 51 can be cut into the protection member 32.

[0044] This prevents damage to the cutting blade 51. If the cutting blade 51 were to be damaged, it would be necessary to restore the cutting edge of the cutting blade 51 by dressing or pre-cutting, or if the blade is damaged to the point where restoration is not possible, it would be necessary to replace the blade, and furthermore, many secondary issues would arise, such as the associated resetting work, but according to this embodiment, such problems can be prevented.

[0045] Furthermore, in the protection mechanism 30, the protection member 32 exists on the extension line of the blade insertion groove 22a in the X-axis direction, so even if the cutting blade 51 cuts into the main body 30a side of the protection mechanism 30, the cutting blade 51 will cut into the protection member 32. This prevents damage to the cutting blade 51. [Explanation of symbols]

[0046] 1 Cutting equipment 2 holding table 3 Imaging unit 5 Cutting unit 6 Base 7 Clamp 8 Cover plate 20 Blade Detection Unit 21 Detection table 22 Optical Sensor 22a Blade insertion groove 22b Wall section 22h horizontal plate part 22z Vertical wall section 23 Light-emitting part 23a Light-emitting surface 24 Light receiving part 24a Photosensitive surface 25 nozzles 26 nozzles 27 Positioning Unit 30 Protection mechanism 30a Main body 30b Mounting groove 31 Rod 32 Protective materials 32w width 41 Y-axis movement mechanism 42 Z-axis movement mechanism 51 Cutting blade Front annular frame T-tape U Wafer Unit double work

Claims

1. A blade detection unit having a light emitting unit and a light receiving unit facing the light emitting unit and receiving light from the light emitting unit, wherein the blade is positioned between the light emitting unit and the light receiving unit to detect the tip of the cutting blade, a protective member inserted between the light-emitting surface of the light-emitting unit and the light-receiving surface of the light-receiving unit and brought into close contact with the light-emitting surface and the light-receiving surface, respectively; a main body to which the protection member is fixed; a positioning unit that moves the main body in a horizontal direction to position the protection member at a protection position where the protection member is inserted between the light-emitting unit and the light-receiving unit, and at a retracted position where the protection member is retracted from the protection position; a detection base that houses the positioning unit and the light emitting unit; a rod that protrudes from the detection base, connects the positioning unit and the main body, and is moved forward and backward by the positioning unit; having Blade detection unit.

2. The protective member is made of a material that is compressively deformable and can be cut by the cutting blade.

2. The blade detection unit according to claim 1.

3. The blade detection unit according to claim 1 or 2; a holding table for holding the workpiece; a cutting unit having a cutting blade for cutting the workpiece held by the holding table; A cutting device comprising:

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