JP6341695B2 - Sub chuck table origin position detection method - Google Patents

Description

  The present invention relates to an origin position detection method for detecting an origin position in a cutting direction of a cutting blade with respect to a sub chuck table.

  2. Description of the Related Art A cutting device is known that includes an origin position detection mechanism that detects an origin position that serves as a setting reference for the cutting amount of a cutting blade (see, for example, Patent Document 1). In the origin position detection mechanism described in Patent Document 1, the conductive cutting blade is lowered toward the chuck table in a rotating state, and the cutting blade's cutting edge comes into contact with the metal frame of the chuck table (when cut). It is configured to conduct. As a result, a current flows into the detection circuit of the origin position detection mechanism, and a voltage fluctuation accompanying a change in the current is detected in the detection circuit. Then, the cutting position of the cutting blade when the voltage fluctuation is detected is set as the origin position.

  A cutting apparatus in which a sub-chuck table is disposed adjacent to a main chuck table for cutting has also been proposed (see, for example, Patent Document 2). A small work piece (sample wafer) and a dresser board are sucked and held on the sub-chuck table, and hairline alignment and dressing of cutting blades can be performed while processing the work piece on the main chuck table. Yes. Also in this sub-chuck table, the position where the cutting blade is brought into contact with the sub-chuck table is set to the origin position in the cutting direction of the cutting blade.

Utility Model Registration No. 2597808 JP 07-283171 A

  By the way, the sub-chuck table performs highly accurate contact-type origin position detection in the same manner as the main chuck table. However, the sub-chuck table is not required to be as accurate as the main chuck table. For example, when dressing a cutting blade with a dresser board on a sub-chuck table, the uncut amount of the dresser board is set in consideration of the thickness variation (several tens of μm) of the dresser board itself. The gap is not a big problem. On the other hand, in order to perform contact-type origin position detection, the sub-chuck table itself requires wiring for origin position detection, which increases the cost.

  The present invention has been made in view of such points, and provides an origin position detection method capable of detecting the origin position in the cutting direction of the cutting blade with respect to the sub chuck table with a simple and inexpensive configuration. Objective.

The method of detecting the origin position of the sub-chuck table according to the present invention includes a chuck table having a holding surface for holding a workpiece, a cutting blade for cutting the workpiece held on the chuck table, and a cutting blade mounted with the cutting blade. A cutting means having a spindle for rotating the image pickup device, an image pickup means for picking up an image of the upper surface of the workpiece held on the chuck table, and a cutting feed means for moving the cutting blade in a cutting feed direction perpendicular to the holding surface. An origin position detecting mechanism for detecting the origin position of the cutting blade in the cutting direction relative to the chuck table by bringing the cutting blade and the chuck table into contact with each other by electrical conduction, and a sub-chuck table disposed in the vicinity of the chuck table. Cutting blade cutting into the sub-chuck table A home position detecting method for detecting the origin position in the direction to detect the direction of the home position notch cutting blade that the holding surface of the chuck table and the reference by the origin position detection mechanism to detect the origin position of the cutting blade A positional relationship calculating step for detecting a focus position of the chuck table in which the imaging means is focused at the holding surface position and calculating a positional relationship between the origin position of the cutting blade in the cutting direction relative to the chuck table and the focus position of the chuck table; After performing the relationship calculation step, the imaging unit focuses on the holding surface of the sub chuck table to detect the focus position of the sub chuck table, and the position relationship calculated in the positional relationship calculation step is determined from the focus position of the sub chuck table. based on, the holding of the sub-chuck table And a home position calculation step of calculating the origin position of the cutting blade relative to the, in the raw point position calculation step, the origin position and the image pickup means the cutting blade relative to the said holding surface of the chuck table The holding surface of the sub-chuck table is set so that the positional relationship between the origin position of the cutting blade with respect to the holding surface of the sub-chuck table and the focus position of the imaging unit is equal to the positional relationship of the focus position. The origin position of the cutting blade as a reference is calculated.

  According to this configuration, the origin position in the cutting direction of the cutting blade with respect to the chuck table is detected with high accuracy by detecting the contact origin position. Further, the focus position of the chuck table is detected by focusing the imaging means on the holding surface position of the chuck table. Then, the positional relationship between the origin position of the cutting blade and the focus position of the image pickup means with respect to the holding surface of the chuck table is obtained. By detecting the focus position of the imaging means in which the imaging means is focused on the holding surface of the sub chuck table, the origin position of the cutting blade with respect to the sub chuck table is calculated from the above positional relationship. In this way, the origin position of the cutting blade is detected with sufficient accuracy for processing the sub-chuck table without bringing the cutting blade into contact with the sub-chuck table. Therefore, it is not necessary to provide wiring for detecting the origin position on the sub chuck table, and the origin position can be detected with a simple and inexpensive configuration.

  According to the present invention, the origin position of the cutting blade relative to the sub-chuck table can be simply and inexpensively determined by obtaining the positional relationship between the origin position of the cutting blade and the focus position of the imaging means with reference to the holding surface of the chuck table. Can be detected.

It is a perspective view of the cutting device concerning this embodiment. It is an enlarged view of the chuck table periphery of the cutting device of FIG. It is explanatory drawing of the origin position detection method which concerns on this Embodiment.

  Hereinafter, the cutting apparatus according to the present embodiment will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a cutting apparatus according to the present embodiment. FIG. 2 is an enlarged view around the chuck table of the cutting apparatus of FIG. Note that the cutting apparatus according to the present embodiment is not limited to the configuration shown in FIGS. 1 and 2. Here, although the cutting device provided with a pair of cutting blade is illustrated, it is not limited to this structure. The present invention can be applied to any cutting apparatus as long as the cutting apparatus includes a sub-chuck table.

  As shown in FIGS. 1 and 2, the cutting apparatus 1 periodically dresses the cutting blade 52 that processes the workpiece W on the chuck table 3 using the dressing board D on the sub-chuck table 4. It is configured. Further, the workpiece W is carried into the cutting apparatus 1 while being supported by the ring frame F via the dicing tape T. The workpiece W may be a semiconductor wafer in which devices such as IC and LSI are formed on a semiconductor substrate such as silicon and gallium arsenide, or an optical device such as an LED on a ceramic, glass, and sapphire inorganic material substrate. It may be a formed optical device wafer.

  The center of the upper surface of the base 2 of the cutting device 1 is opened in a rectangular shape so as to extend in the X-axis direction, and a moving plate 31 and a waterproof cover 32 are provided so as to cover the opening. On the moving plate 31, there is provided a chuck table 3 that can rotate around the Z-axis. Below the waterproof cover 32 and the moving plate 31, processing feed means (not shown) for moving the chuck table 3 in the X-axis direction is provided. A holding surface 33 for holding the workpiece W is formed on the upper surface of the chuck table 3. The central region of the holding surface 33 is a suction region by the porous 34, and is a conductive region in which the metal frame 35 is exposed around the suction region.

  Around the chuck table 3, there are provided four clamp portions 36 that sandwich and fix the ring frame F around the workpiece W. A sub chuck table 4 is provided on the movable plate 31 in the vicinity of the chuck table 3. A lattice-shaped shallow groove 41 is formed on the upper surface of the sub chuck table 4 to form a holding surface 42, and the dressing board D is sucked and held on the holding surface 42. On the upper surface of the base 2, a gate-shaped column portion 21 is provided so as to stand over an opening extending in the X-axis direction. The columnar column portion 21 is provided with an index feed means 6 and a cut feed means 7 that move the pair of cutting means 5 relative to the workpiece W on the chuck table 3.

  The index feed means 6 moves the pair of cutting means 5 in the index feed direction (Y-axis direction), and the cut feed means 7 pairs in the cut feed direction (Z-axis direction) perpendicular to the holding surface 33. The cutting means 5 is moved. The index feeding means 6 includes a pair of guide rails 61 parallel to the Y-axis direction with respect to the front surface of the column portion 21 and a pair of motor-driven Y-axis tables 62 slidably installed on the pair of guide rails 61. have. Further, the cutting feed means 7 includes a pair of guide rails 71 disposed in front of each Y-axis table 62 and parallel to the Z-axis direction, and a motor-driven Z-axis table 72 slidably installed on the guide rail 71. And have.

  A cutting means 5 for cutting the workpiece W is provided below each Z-axis table 72. Further, nut portions (not shown) are formed on the back side of each Y-axis table 62, and a ball screw 63 is screwed to these nut portions. Further, nut portions (not shown) are formed on the back side of each Z-axis table 72, and a ball screw 73 is screwed to these nut portions. Drive motors 64 and 74 are connected to one end of a ball screw 63 for the Y-axis table 62 and a ball screw 73 for the Z-axis table 72, respectively. The ball screws 63 and 73 are rotationally driven by the drive motors 64 and 74, whereby the pair of cutting means 5 are moved along the guide rails 61 and 71 in the Y-axis direction and the Z-axis direction.

  The pair of cutting means 5 is configured by mounting a cutting blade 52 on a spindle 51. The cutting blade 52 is covered with a blade cover 53, and the blade cover 53 is provided with an injection nozzle that injects cutting water toward the cutting portion. The spindle 51 is provided with an image pickup means 55 for picking up an upper surface of the workpiece W, and the cutting blade 52 is aligned with the workpiece W based on the image picked up by the image pickup means 55. In the pair of cutting means 5, the workpiece W is cut along the planned division lines by the cutting blade 52 while the cutting water is jetted from the plurality of jet nozzles, thereby being divided into individual devices.

  Further, the cutting device 1 is provided with a control means 9 that performs overall control of each part of the device. The control means 9 includes a processor that executes various processes, a memory, and the like. The memory is composed of one or a plurality of storage media such as a ROM (Read Only Memory) and a RAM (Random Access Memory) depending on the application. The memory stores not only various processing conditions of the cutting apparatus 1 but also, for example, a program for detecting the origin position of the cutting blade 52 with respect to the chuck table 3 and a program for detecting the origin position of the cutting blade 52 with respect to the sub chuck table 4. Has been.

  In such a cutting apparatus 1, the origin position detection mechanism 11 (see FIG. 3) that sets the origin position in the cutting direction of the cutting blade 52 is provided before the workpiece W is processed. The origin position detection mechanism 11 is a so-called contact-type origin position detection mechanism, and contacts the metal frame 35 on the outer peripheral portion of the chuck table 3 with a conductive cutting blade 52 so as to be electrically connected to the chuck table. 3, the origin position (height) of the cutting blade 52 with respect to 3 is detected. Further, since the cutting apparatus 1 is provided with the sub chuck table 4, it is necessary to detect the origin position in the cutting direction of the cutting blade 52 with respect to the sub chuck table 4.

  Similarly to the chuck table 3, when contact-type origin position detection is performed on the sub-chuck table 4, various wirings are required for the sub-chuck table 4, and the apparatus configuration becomes complicated. Therefore, in the present embodiment, an alignment imaging means 55 is used for the sub-chuck table 4 to detect the origin position in the cutting direction of the cutting blade 52 in a non-contact manner. Thereby, the wiring for detecting the origin position is not required for the sub chuck table 4, and the apparatus cost can be reduced. Hereinafter, the origin position detection method of the sub chuck table 4 according to the present embodiment will be described in detail.

  FIG. 3 is an explanatory diagram of the origin position detection method according to the present embodiment. The origin position detection method is a method of detecting the origin position of the cutting blade with respect to the sub chuck table through the positional relationship calculation step and the origin position calculation step. 3A and 3B show a positional relationship calculation step, and FIGS. 3C and 3D show an origin position calculation step, respectively. In the chuck table, the surface of the metal frame is flush with the surface of the porous surface, and the height of the cutting blade from the surface of the metal frame is detected as the height of the cutting blade from the holding surface.

As shown in FIG. 3A, in the positional relationship calculation step, contact-type origin position detection by the origin position detection mechanism 11 is performed. In the contact-type origin position detection, the cutting blade 52 is positioned above the metal frame 35 of the chuck table 3 and is lowered toward the chuck table 3 while the cutting blade 52 is rotated. Then, the cutting edge of the cutting blade 52 comes into contact with the surface (holding surface 33) of the metal frame 35 of the chuck table 3, and the conductive cutting blade 52 and the metal frame 35 of the chuck table 3 are electrically connected. The height of the cutting blade 52 at this time is measured by the linear scale 12 or the like, and is detected as the origin position Z _{1 in} the cutting direction of the cutting blade 52 with respect to the chuck table 3 by the origin position detection mechanism 11. In addition, the linear scale 12 is provided in the cutting feed means 7, for example.

As shown in FIG. 3B, the focus position of the chuck table 3 is detected by the imaging means 55 in the positional relationship calculation step. In detecting the focus position of the chuck table 3, the imaging means 55 is positioned above the metal frame 35 of the chuck table 3, and the contact position of the cutting blade 52 with respect to the metal frame 35 is included in the imaging range. Then, the height of the imaging means 55 is adjusted so that the focus of the imaging means 55 is adjusted to the surface (holding surface 33) of the metal frame 35. The height of the image pickup means 55 at this time is measured by the linear scale 12 or the like, is detected as the focus position Z ₂ of the image pickup means 55 with respect to the chuck table 3. The focus position detection is preferably performed at a position where the cutting blade 52 contacts the metal frame 35 in the origin position detection. In this case, when a cutting groove is formed in the metal frame 35, focus position detection is performed in the vicinity of the cutting groove.

The detection results of contact-type origin position detection and focus position detection are output to the control means 9 (see FIG. 1), and the control means 9 causes the origin position Z _{1 in} the cutting direction of the cutting blade 52 and the focus position Z _{2 of the} imaging means 55. Is calculated. For example, as the positional relationship, a difference ΔZ _1-2 between the origin position Z ₁ in the cutting direction of the cutting blade 52 in the height direction (Z-axis direction) and the focus position Z ₂ of the imaging unit 55 is calculated. Thus, the positional relationship between the focus position Z ₂ in the height direction of the origin position Z ₁ and the imaging unit 55 of the cutting blade 52 relative to the holding surface 33 of the chuck table 3 is obtained.

Next, after performing the positional relationship calculation step, the origin position calculation step is performed. As shown in FIG. 3C, the focus position of the sub chuck table 4 is detected by the imaging means 55 in the origin position calculating step. In detecting the focus position of the sub chuck table 4, the image pickup means 55 is positioned above the holding surface 42 of the sub chuck table 4, and the height of the image pickup means 55 is adjusted so as to be focused on the holding surface 42 of the sub chuck table 4. Adjusted. The height of the imaging means 55 when the imaging means 55 is focused on the holding surface 42 of the sub chuck table 4 is measured by the linear scale 12 or the like, and is used as the focus position Z ₄ of the imaging means 55 with respect to the sub chuck table 4. Detected.

As shown in FIG. 3D, in the origin position calculating step, the origin position Z ₃ of the cutting blade 52 relative to the sub chuck table 4 is calculated from the focus position Z ₄ of the imaging means 55 relative to the sub chuck table 4 based on the above positional relationship. Is done. In this case, the positional relationship between the focus position Z ₂ of the origin position Z ₁ and the imaging unit 55 of the cutting blade 52 relative to the holding surface 33 of the chuck table 3 (see FIG. 3B), a holding surface 42 of the sub-chuck table 4 positional relationship between the focus position _{Z 4} of the origin position _{Z 3} and the imaging unit 55 of the cutting blade 52 on the basis is based on the fact that equal (difference [Delta] Z _1-2 = difference [Delta] Z _3-4).

That is, with respect to the focus position Z ₄ of the imaging means 55 based on the holding surface 42 of the sub chuck table 4 so as to have the same positional relationship as the difference ΔZ _1-2 obtained in the positional relationship calculation step (see FIG. 3B). The origin position Z ₃ of the cutting blade 52 is calculated (Z ₃ = Z ₄ + difference ΔZ _1-2 ). Origin position Z ₃ of the cutting blade 52 relative to the sub-chuck table 4 is calculated from the focus position Z ₄ of the image pickup means 55 with respect to the sub-chuck table 4 as the difference [Delta] Z _1-2 position lower. In this way, without contacting the cutting blade 52 in the sub-chuck table 4, the origin position Z ₃ of the cutting blade 52 relative to the sub-chuck table 4 with a precision close to the origin position detection of the contact type is detected.

In FIG. 3, the positional relationship calculation step, after detecting the home position Z ₁ of the cutting blade 52 with respect to the chuck table 3, a configuration for detecting the focus position Z ₂ of the chuck table 3, limited to this structure Not. In the positional relationship calculation step, after detecting the focus position Z ₂ of the chuck table 3 it may detect the origin position Z ₁ of the cutting blade 52 with respect to the chuck table 3. Thus, before a slight cut groove is formed on the upper surface of the metal frame 35 of the chuck table 3 by the cutting blade 52, it is possible to detect the focus position Z ₂ of the chuck table 3, the error in focus position Z ₂ by the cutting grooves Will not occur.

In FIG. 3, in the origin position calculating step, the focus position is detected by focusing on the holding surface 42 of the sub chuck table 4. However, the present invention is not limited to this configuration. In the origin position calculating step, it is also possible to detect the focus position by focusing on the dressing board D (see FIG. 2) held on the sub chuck table 4 or the upper surface of the small piece workpiece. In this case, as the same positional relationship between the difference [Delta] Z _1-2 obtained in the positional relationship calculation step (see FIG. 3B), the imaging unit 55 relative to the upper surface of the dressing board D or pieces workpiece The origin position of the cutting blade 52 with respect to the focus position is calculated. When the top surface of the dressing board D or the small piece workpiece is used as a reference, the cutting amount is set based on the top surface of the dressing board D or the small piece workpiece. Thereby, even when the thickness variation is large (for example, 100 μm) as in the case of the dressing board D, the cutting amount is easily controlled by using the board upper surface as a reference.

As described above, according to the cutting apparatus 1 according to this embodiment, the positional relationship between the focus position Z ₂ of the origin position Z ₁ and the imaging unit 55 of the cutting blade 52 relative to the holding surface 33 of the chuck table 3 Is required. By focus position Z ₄ of the image pickup means 55 to focus the image pickup means 55 on the holding surface 42 of the sub-chuck table 4 is detected, the origin of the cutting blade 52 relative to the sub-chuck table 4 from the positional relationship position _{Z 3} is calculated. Thus, the origin position of the cutting blade 52 is detected with an accuracy close to that of contact-type origin position detection without bringing the cutting blade 52 into contact with the sub-chuck table 4. Further, since the origin position of the cutting blade 52 with respect to the sub chuck table 4 is detected in a non-contact manner, it is not necessary to provide a wiring for origin position detection on the sub chuck table 4, and further, an imaging means 55 for alignment is used for detecting the focus position. Therefore, the origin position can be detected with a simple and inexpensive configuration.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the above-described embodiment, the dressing board D is held by the sub-chuck table 4, but the present invention is not limited to this configuration. In addition to the dressing board D, the sub-chuck table 4 may hold a sample wafer for kerf check.

In the above-described embodiment, the focus positions Z ₂ and Z ₄ with respect to the chuck table 3 and the sub chuck table ₄ are detected by the alignment imaging unit 55, but the present invention is not limited to this configuration. In addition to the imaging unit 55 for alignment, an imaging unit for detecting the origin position may be provided.

Further, in the above-described embodiment, as a positional relationship between the focus position Z ₂ of the origin position Z ₁ and the imaging unit 55 of the cutting blade 52 with respect to the chuck table 3, the focus of the origin position Z ₁ and the imaging unit 55 of the cutting blade 52 It has a structure represented by the difference between Z _1-2 position Z _2, but is not limited to this configuration. For the positional relationship, it is only necessary to know the positional relationship between the cutting blade 52 and the image pickup means 55 with reference to the holding surface 33 of the chuck table 3, for example, the origin position Z ₁ of the cutting blade 52 and the focus position Z ₂ of the image pickup means 55. It may be represented by a ratio Z ₁ / Z ₂ .

  As described above, the present invention has an effect that the origin position in the cutting direction of the cutting blade with respect to the sub chuck table can be detected with a simple and inexpensive configuration, and in particular, the origin of the sub chuck table holding the dressing board. Useful for position detection methods.

DESCRIPTION OF SYMBOLS 1 Cutting device 3 Chuck table 4 Sub chuck table 5 Cutting means 7 Cutting feed means 11 Origin position detection mechanism 33 Chuck table holding surface 42 Sub chuck table holding surface 51 Spindle 52 Cutting blade 55 Imaging means

Claims (1)

A cutting means having a chuck table having a holding surface for holding a workpiece, a cutting blade for cutting the workpiece held on the chuck table, and a spindle on which the cutting blade is mounted and which rotates the cutting blade. Imaging means for imaging the upper surface of the workpiece held on the chuck table, cutting feed means for moving the cutting blade in a cutting feed direction perpendicular to the holding surface, the cutting blade and the chuck Cutting provided with an origin position detection mechanism for detecting an origin position in the cutting direction of the cutting blade with respect to the chuck table by electrical contact with the table, and a sub-chuck table disposed in the vicinity of the chuck table In the apparatus, the origin position in the cutting direction of the cutting blade with respect to the sub chuck table is detected. A home position detection method,
The origin position detecting mechanism detects the origin position of the cutting blade in the cutting direction with respect to the holding surface of the chuck table , and the imaging means is focused at the holding surface position for detecting the origin position of the cutting blade. A positional relationship calculating step of detecting a focus position of the chuck table and calculating a positional relationship between the origin position of the cutting blade in the cutting direction relative to the chuck table and the focus position of the chuck table;
After performing the positional relationship calculation step, the imaging unit focuses on the holding surface of the sub chuck table to detect the focus position of the sub chuck table, and the positional relationship is determined from the focus position of the sub chuck table. An origin position calculating step for calculating the origin position of the cutting blade based on the holding surface of the sub chuck table based on the positional relationship calculated in the calculating step ,
In the origin position calculation step, the cutting position based on the holding surface of the sub-chuck table is set to the positional relationship between the origin position of the cutting blade with respect to the holding surface of the chuck table and the focus position of the imaging means. Sub-chuck table origin position detection method in which the origin position of the cutting blade is calculated with reference to the holding surface of the sub-chuck table so that the positional relationship between the origin position of the blade and the focus position of the imaging means is equal. .

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