Cutting device and cutting method

Abstract

To provide a new technique for enabling a cutting blade to be accurately set up, by removing chips adhering onto an inspection piece.SOLUTION: A cutting device 2 comprises: a holding table 16 on which a work-piece is held; a cutting unit 26 having a spindle 48 to which a cutting blade 50 that cuts the work-piece held on the holding table 16 is attached; an inspection-piece table 70 which holds an inspection piece 78 that forms a notched / cut trace 75 using the cutting blade 50; a photographing camera 29 that photographs the cut trace 75 formed in the inspection piece 78; and a cleaning liquid supply nozzle 74 that supplies cleaning liquid to the inspection piece 78 held on the inspection-piece table 70.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cutting device and a cutting method for cutting a workpiece with a cutting blade that rotates at high speed. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known a cutting device that cuts a plate-shaped workpiece such as a semiconductor wafer using a cutting blade made of a grindstone in which abrasive grains such as diamond are bonded with a bond material (see, for example, Patent Document 1).

[0003] In cutting, it is necessary to recognize the tip position of the cutting blade, set it up to a specified height, and perform cutting at a specified cutting depth. In particular, when performing half cuts, which cut grooves to about half the depth without cutting completely through a plate-like workpiece, it is necessary to be able to recognize the tip position of the cutting blade with high precision.

[0004] Patent Document 1 describes a so-called chopper cut setup in which a cutting mark is formed on a test piece using a chopper cut, and the diameter of the cutting blade is calculated based on the image formed by capturing the cutting mark with an imaging camera, and the tip position of the cutting blade is recognized and its height is set up. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2016-213342 Summary of the Invention [Problem to be solved by the invention]

[0006] When the test piece is cut during setup, cutting debris adheres to the test piece. In addition, because the test piece is placed near the holding table that holds the workpiece, cutting debris also adheres to the test piece.

[0007] If cutting debris remains on the test piece, it will appear in the captured image, making it impossible to accurately calculate the length of the cutting mark or the diameter of the cutting blade, and therefore making it impossible to accurately set up the test piece. If cutting is performed in this state, the desired cutting depth will not be achieved, resulting in processing defects.

[0008] In view of the above problems, the present invention provides a novel technique for enabling accurate setup of the cutting blade by removing cutting debris adhering to the test piece. [Means for solving the problem]

[0009] The problem to be solved by the present invention is as described above, and the means for solving this problem will now be described.

[0010] According to one aspect of the present invention, A cutting device comprising: a holding table for holding a workpiece; a cutting unit having a spindle to which a cutting blade for cutting the workpiece held by the holding table is attached; a test piece table for holding a test piece on which a cutting mark is formed by the cutting blade; and an imaging camera for imaging the cutting mark formed on the test piece, The cutting device is provided with a cleaning liquid supply nozzle for supplying cleaning liquid to the test piece held by the test piece table.

[0011] According to another aspect of the present invention, A cutting method for cutting a test piece separate from a workpiece, comprising: a cutting mark forming step in which the cutting blade cuts into the test piece held on the test piece table at a predetermined timing to form a cutting mark; a cutting mark imaging step of imaging the cutting mark formed on the test piece with an imaging camera to form an image, The cutting method is such that the upper surface of the test piece is cleaned before the cutting mark imaging step is carried out.

[0012] According to another aspect of the present invention, a cleaning liquid supply nozzle is attached to the test strip table to supply cleaning liquid to the test strip held by the test strip table; In the cutting trace imaging step, the cleaning liquid is supplied from the cleaning liquid supply nozzle to the test piece except for the time when the imaging camera is imaging the cutting trace. [Effects of the Invention]

[0013] According to the present invention, a cleaning liquid is supplied to a test piece held on a test piece table, preventing cutting debris from adhering to the test piece. Even if cutting debris does adhere to the test piece, the debris is removed, preventing the cutting debris from appearing in captured images. This allows the length of the cutting mark and the diameter of the cutting blade to be accurately calculated, enabling accurate cutting blade setup. Furthermore, this more accurate setup makes it possible to suit situations where the tip position of the cutting blade must be recognized with higher precision, such as when performing a half cut. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating an example of a cutting device. [Figure 2] 10A and 10B are diagrams showing how a chamfered portion is trimmed. [Figure 3] FIG. 2 is a diagram showing the configuration of a test piece table. [Figure 4] (A) is a diagram explaining the cutting depth, etc. (B) is a diagram showing cutting marks. [Figure 5] 1 is a flowchart showing the order of each step. [Figure 6] 5A to 5C are diagrams illustrating a cutting trace forming step. [Figure 7] 5A to 5C are diagrams illustrating a cutting trace forming step. [Figure 8] 10A to 10C are diagrams illustrating a cutting mark imaging step. [Figure 9] 10A and 10B are diagrams showing an example of cleaning a test piece using a cleaning liquid nozzle provided in a cutting unit. DETAILED DESCRIPTION OF THE INVENTION

[0015] The following describes in detail an embodiment of the present invention with reference to the drawings. In the following embodiment, a trimming device that removes chamfered portions of a wafer is used as an example of a cutting device, but the present invention can also be applied to a cutting device that dices a wafer by cutting, a cutting device that half-cuts a wafer to half its thickness, and the like.

[0016] Fig. 1 is a perspective view that schematically shows an example of the configuration of a processing device according to this embodiment. As shown in Fig. 1, a cutting device 2 includes a base 4 that supports each component. A rectangular opening 4a that is long in the Y-axis direction (left-right direction, indexing feed direction) is formed on the front end side of the upper surface of the base 4, and a first transport mechanism 6 for transporting a wafer 11 is disposed within this opening 4a.

[0017] A rectangular opening 4b is formed behind one end of the opening 4a in the Y-axis direction, and a cassette support table 8 is provided in this opening 4b so that it can move up and down. A rectangular parallelepiped cassette 10 that stores a plurality of wafers (workpieces) 11 is placed on the upper surface of the cassette support table 8.

[0018] The wafer 11 is a circular substrate made of a semiconductor such as silicon, and its surface 11a is divided into a central device region (central portion) and a peripheral surplus region (periphery portion) surrounding the device region. The device region is further divided into multiple regions by planned division lines (streets) arranged in a grid pattern, and devices 13 such as ICs and LSIs are formed in each region.

[0019] The wafer 11 also has a chamfered portion 11c (FIG. 2) formed by chamfering the outer periphery. The cutting device 2 trims this chamfered portion 11c. In this embodiment, the wafer 11 is a circular substrate made of a semiconductor such as silicon, but there are no limitations on the material, shape, etc. of the wafer 11. For example, a substrate made of a material such as ceramic, resin, or metal can also be used as the wafer 11.

[0020] A rectangular opening 4c that is long in the X-axis direction (front-rear direction, processing feed direction) is formed diagonally behind the cassette support base 8. Inside this opening 4c, there are provided an X-axis moving table 12, an X-axis moving mechanism (processing feed means) (not shown) that moves the X-axis moving table 12 in the X-axis direction, and a dustproof and drip-proof cover 14 that covers the X-axis moving mechanism.

[0021] A holding table 16 is provided at the position of the X-axis moving table 12 to hold the outer peripheral portion of the wafer 11 transferred from the cassette 10 by the first transfer mechanism 6. This holding table 16 is connected to a rotation drive mechanism (not shown) such as a motor, and rotates around a rotation axis that is roughly parallel to the Z-axis direction (vertical direction). In addition, the holding table 16 is fed for processing in the X-axis direction together with the X-axis moving table 12 by the above-mentioned X-axis moving mechanism.

[0022] As shown in FIG. 2, the holding table 16 is configured to have a cylindrical base portion 18 made of a metal such as stainless steel, an annular holding surface 20 which is the upper surface of a convex portion 20a which protrudes in an annular shape from the peripheral portion of the base portion 18, and a suction portion 21 which is configured as a space formed inside the annular holding surface 20.

[0023] The chamfered portion 11c of the wafer 11 is placed on the annular holding surface 20, and the chamfered portion 11c of the wafer 11 is held from below.

[0024] The suction unit 21 is connected to a suction source 24 through a suction path 18a formed inside the base unit 18 and a valve 22, and holds the back surface 11b of the wafer 11 by suction from below.

[0025] 1, a gate-shaped support structure 28 that supports two cutting units 26 is disposed across the opening 4c on the upper surface of the base 4. Two cutting unit movement mechanisms (indexing and feeding means, lifting and lowering means) 30 that move each cutting unit 26 in the Y-axis direction and the Z-axis direction are provided on the upper front surface of the support structure 28.

[0026] Each cutting unit movement mechanism 30 is provided with a pair of Y-axis guide rails 32 that are arranged in front of the support structure 28 and are generally parallel to the Y-axis direction. A Y-axis movement plate 34 that constitutes each cutting unit movement mechanism 30 is slidably attached to the Y-axis guide rails 32.

[0027] A nut (not shown) is provided on the rear surface (back surface) of each Y-axis moving plate 34, and a Y-axis ball screw 36 that is generally parallel to the Y-axis guide rail 32 is threadedly engaged with this nut. A Y-axis pulse motor 38 is connected to one end of each Y-axis ball screw 36. When the Y-axis pulse motor 38 rotates the Y-axis ball screw 36, the Y-axis moving plate 34 moves in the Y-axis direction along the Y-axis guide rail 32.

[0028] A pair of Z-axis guide rails 40 that are generally parallel to the Z-axis direction are provided on the front surface (surface) of each Y-axis moving plate 34. A Z-axis moving plate 42 is slidably attached to the Z-axis guide rails 40.

[0029] A nut (not shown) is provided on the rear surface (back surface) of each Z-axis moving plate 42, and a Z-axis ball screw 44 that is generally parallel to the Z-axis guide rail 40 is threadedly engaged with this nut. A Z-axis pulse motor 46 is connected to one end of each Z-axis ball screw 44. When the Z-axis pulse motor 46 rotates the Z-axis ball screw 44, the Z-axis moving plate 42 moves in the Z-axis direction along the Z-axis guide rail 40.

[0030] A cutting unit 26 is provided below each Z-axis moving plate 42. As shown in Fig. 2, the cutting unit 26 includes a spindle 48 (Fig. 2) that serves as a rotation axis that is generally parallel to the Y-axis direction. An annular cutting blade 50 is attached to one end of the spindle 48, and a rotation drive source such as a motor is connected to the other end of the spindle 48.

[0031] 1, an imaging camera 29 is disposed near each cutting unit 26 to capture an image of the wafer 11 or the like on the holding table 16. As will be described in detail later, the imaging camera 29 is also used to capture an image of cutting marks formed on the test piece.

[0032] A circular opening 4d is formed behind the end of the other side of opening 4a in the Y-axis direction (opposite opening 4b). A wafer cleaning unit 52 that cleans processed wafers 11 is provided inside opening 4d. Wafer cleaning unit 52 includes a spinner table 54 that sucks and holds wafers 11, and a nozzle 56 that sprays cleaning fluid onto wafers 11 sucked and held by spinner table 54.

[0033] A second transfer mechanism 62 is disposed near the openings 4c and 4d to transfer the processed wafer 11 from the holding table 16 to the spinner table 54. The second transfer mechanism 62 includes a plurality of gripping parts 64 for gripping the outer peripheral edge of the wafer 11.

[0034] The wafer 11 on the holding table 16 can be gripped by the gripping portion 64 by moving the gripping portion 64 in the radial direction of the wafer 11 in line with the slits formed in the annular holding surface 20 of the holding table 16. The wafer 11 transported by the second transport mechanism 62 is placed on the holding surface of the spinner table 54, for example, with the front surface 11a exposed upward. The wafer 11 after cleaning is stored in the cassette 10 by the first transport mechanism 6.

[0035] 1, the X-axis moving table 12 is provided with a test piece table 70 for holding a test piece 78 on which a cutting mark is formed by the cutting blade of the cutting unit 26. In this embodiment, two test piece tables 70 are provided, and a configuration is provided in which chopper cut setup is possible for each cutting unit 26.

[0036] As shown in Figure 3, the test piece table 70 has a base portion 71, a suction holding surface 72 formed on the upper surface of the base portion 71, and a cleaning liquid supply nozzle 74 for supplying cleaning liquid toward the surface of the test piece 78 held by the suction holding surface 72.

[0037] The suction holding surface 72 is formed with a suction groove 72 a that is connected to a suction source (not shown), and the test piece 78 is sucked and held by the negative pressure generated on the suction holding surface 72 .

[0038] A plurality of cleaning liquid supply nozzles 74 are arranged in a line so that the spray direction is toward the suction hold surface 72. Each cleaning liquid supply nozzle 74 is connected to a cleaning liquid supply source (not shown). The cleaning liquid is, for example, cleaning water such as pure water.

[0039] In this embodiment, a protrusion is provided on the base portion 71, and multiple cleaning liquid supply nozzles 74 are arranged on the side of the protrusion, but this is not particularly limited to this form, and a separate cleaning liquid supply nozzle independent of the test piece table 70 may also be arranged near the test piece table 70.

[0040] It is preferable that the cleaning liquid be supplied continuously from the cleaning liquid supply nozzle 74 except for the time when the cutting marks are being imaged in the cutting mark imaging step described below. This allows the surface of the test piece 78 to be constantly washed away, preventing the adhesion of foreign matter such as cutting chips.

[0041] The test piece 78 is a rectangular plate-like member, and as shown in Figures 4(A) and (B), groove-like cutting marks 75 are formed by cutting with the cutting blade 50. The test piece 78 may be made of the same material as the wafer 11 (Figure 1), which is the workpiece of the cutting device, or it may be made of a different material.

[0042] As shown in Figures 4(A) and (B), the cutting mark 75 is imaged by the imaging camera 29 (Figure 1), the cutting mark length W is detected based on the captured image, and the cutting depth d of the cutting mark 75 is detected based on this cutting mark length W. R 2 =a 2 +((1 / 2)×W) 2 d=R―a R: Blade radius W: Cutting scar length d: cutting depth a: Distance from the height position Z1 of the rotation center of the spindle 48 to the surface of the test piece 78 when the cut is made (the distance from the rotation center of the spindle 48 to the suction holding surface 72 of the test piece table 70 minus the thickness 78d of the test piece 78)

[0043] Then, as shown in Figure 4(A), based on the cutting depth d of the cutting mark 75 obtained in this manner and the height difference Δ between the annular holding surface 20 of the holding table 16 and the suction holding surface 72 of the test piece table 70, the height position Z at which the tip of the cutting blade 50 contacts the annular holding surface 20 is calculated using d+Δ as a correction value.

[0044] This height position Z is the Z-axis coordinate position of the rotation center of the spindle 48, and for example, a position where no cutting is made by the cutting blade 50 is set as the reference position Z0 (FIG. 2). Note that the distance from the reference position Z0 to the annular holding surface 20 of the holding table 16 and the distance to the suction holding surface 72 of the test piece table 70 are set in advance.

[0045] 4(A), when the difference in height Δ between the annular holding surface 20 and the suction holding surface 72 is zero, that is, when the annular holding surface 20 and the suction holding surface 72 are the same height, the value ΔZ obtained by subtracting the cutting depth d from the thickness 78d of the test piece 78 can be defined as the distance from the tip of the cutting blade 50 to the annular holding surface 20. Then, the height position Z2, which is lower by the value ΔZ from the height position Z1 of the rotation center of the spindle 48 when the cutting is made, becomes the height position Z of the rotation center of the spindle 48 when the tip of the cutting blade 50 comes into contact with the annular holding surface 20.

[0046] Next, we will explain the cutting method and setup using the above-mentioned device configuration. Figure 5 is a flowchart showing the order of each of the following steps.

[0047] <Cutting step> 2, this is a step of cutting the workpiece, and in this embodiment, this is a step of trimming the chamfered portion 11c of the wafer 11 held on the holding table 16. At this time, a cleaning liquid is continuously supplied from a cleaning liquid supply nozzle 74 (FIG. 3) toward the test piece 78.

[0048] This supply of cleaning liquid is continued except for the time when the cutting marks are being imaged by the imaging camera in the next cutting mark imaging step. As a result, a so-called water curtain of cleaning liquid is formed on the test piece 78 during the cutting step, and it is possible to prevent cutting debris generated by cutting from adhering to the test piece 78.

[0049] <Cutting mark formation step> As shown in FIGS. 6 and 7, this is a step in which the cutting blade 50 cuts into the test piece 78 held on the test piece table 70 at a predetermined timing, forming a cutting mark 75 (FIG. 4(B)).

[0050] The predetermined timing is, for example, the timing when processing of all the wafers 11 contained in one cassette 10 (FIG. 1) is completed.

[0051] As shown in Figure 6, even when cutting the test piece 78 to form the cutting marks 75 (Figure 4(B)), cleaning liquid is continuously supplied from the cleaning liquid supply nozzle 74 (Figure 3) toward the test piece 78, so that foreign matter such as cutting chips generated by cutting is constantly washed away.

[0052] <Cutting mark imaging step> As shown in FIG. 8, this is a step in which the cutting marks 75 formed on the test piece 78 are photographed by the imaging camera 29 to form a photographed image.

[0053] Specifically, first, the supply of cleaning liquid from the cleaning liquid supply nozzle 74 (FIG. 3) is stopped. This stoppage continues until imaging is completed. Next, air is blown from the air nozzle 29a attached to the imaging camera 29 toward the test piece 78 to remove any moisture remaining on the surface of the test piece 78. Note that the air nozzle 29a may be provided separately from the imaging camera 29.

[0054] Since the test piece 78 is constantly cleaned and moisture is blown away by air blowing, no foreign matter is visible in the captured image, making it possible to accurately calculate the length of the cutting mark 75 through image analysis.

[0055] <Height position calculation step> As shown in FIGS. 4(A) and 4(B), this is a step of calculating the height position Z at which the tip of the cutting blade 50 contacts the annular holding surface 20 based on the length of the cutting mark 75 that appears in the captured image.

[0056] As described above, the height position Z at which the tip of the cutting blade 50 contacts the annular retaining surface 20 is obtained on the Z-axis coordinate of the center of rotation of the spindle 48, and this makes it possible to set up the position of the tip of the cutting blade 50 when the cutting blade 50 becomes worn or is replaced with a new one.

[0057] In the configuration described above, the cleaning liquid supply nozzle 74 is provided on the test piece table 70 as shown in Fig. 3, but as shown in Fig. 9, cleaning liquid may be supplied to the test piece 78 from a cleaning liquid nozzle 26a provided on the cutting unit 26. This cleaning liquid nozzle 26a is also used to clean the annular holding surface 20 of the holding table 16 shown in Fig. 1.

[0058] 9 is used, for example, when processing of all the wafers 11 contained in one cassette 10 shown in Fig. 1 has been completed, the cleaning liquid is supplied from the cleaning liquid nozzle 26a (Fig. 9) to the annular holding surface 20 of the holding table 16 while the holding table 16 is rotated to clean the annular holding surface 20. Thereafter, as shown in Fig. 9, the cleaning liquid is supplied from the cleaning liquid nozzle 26a to the upper surface of a test piece 78 held on a test piece table 70 to clean the upper surface of the test piece 78.

[0059] As described above, according to the present invention, as shown in FIG. 6, a cleaning liquid is supplied to the test piece 78 held on the test piece table 70, preventing cutting debris from adhering to the test piece 78. Even if cutting debris does adhere to the test piece 78, the cutting debris is removed, preventing the cutting debris from appearing in the captured image. This allows the length of the cutting mark 75 (FIG. 4(B)) and the diameter of the cutting blade 50 to be accurately calculated, enabling accurate setup of the cutting blade 50. Furthermore, this more accurate setup makes it possible to suit situations where the tip position of the cutting blade 50 needs to be recognized with higher precision, such as when performing a half cut. [Explanation of symbols]

[0060] 2 Cutting equipment 6. Conveyor mechanism 8 Cassette support stand 10 cassettes 11 wafers 11c Chamfered part 16 Holding table 20 Annular retaining surface 26 Cutting unit 26a Cleaning liquid nozzle 29 Imaging camera 29a Air nozzle 48 Spindle 50 cutting blades 70 Test piece table 71 Base 72 Suction holding surface 72a Suction groove 74 Cleaning liquid supply nozzle 75 Cutting marks 78 Test Strips d cutting depth R Blade Radius W Cutting scar length Z height position Z0 reference position

Claims

1. A cutting device comprising: a holding table for holding a workpiece; a cutting unit having a spindle to which a cutting blade for cutting the workpiece held by the holding table is attached; a test piece table for holding a test piece on which a cutting mark is formed by the cutting blade; and an imaging camera for imaging the cutting mark formed on the test piece, a cleaning liquid supply nozzle for supplying a cleaning liquid to the test strip held by the test strip table; the cleaning liquid supply nozzle is provided on the test piece table; Or, The cleaning liquid supply nozzle is provided on the cutting unit. cutting equipment.

2. A cutting method for cutting a test piece separate from a workpiece, comprising: a cutting mark forming step in which a cutting blade of the cutting unit cuts into the test piece held on the test piece table at a predetermined timing to form a cutting mark; a cutting mark imaging step of imaging the cutting mark formed on the test piece with an imaging camera to form an image, The upper surface of the test piece is cleaned before the cutting mark imaging step is performed; The cleaning is performed by a cleaning liquid supply nozzle that supplies a cleaning liquid to the test strip, the cleaning liquid supply nozzle is provided on the test piece table; Or, The cleaning liquid supply nozzle is provided in the cutting unit.

3. A cutting method for cutting a test piece separate from a workpiece, comprising: a cutting mark forming step in which the cutting blade cuts into the test piece held on the test piece table at a predetermined timing to form a cutting mark; a cutting mark imaging step of imaging the cutting mark formed on the test piece with an imaging camera to form an image, A cutting method in which an upper surface of the test piece is cleaned before the cutting mark imaging step is performed, a cleaning liquid supply nozzle is attached to the test strip table to supply cleaning liquid to the test strip held by the test strip table; The cutting method, wherein the cleaning liquid is supplied from the cleaning liquid supply nozzle to the test piece except while the imaging camera is imaging the cutting marks in the cutting mark imaging step.

Images