Measuring method, measuring apparatus, and processing method for work-piece

Abstract

To measure a height of an upper surface of a stepped part formed on a measurement target object such as a wafer.SOLUTION: A measuring method, which measures a height of an upper surface of a stepped part formed on an outer periphery of a front surface side of a measurement target object, comprises: a holding step of holding, by a holding table, a back surface side of the measurement target object so that the stepped part is exposed upward; and a measuring step of measuring the height of the upper surface of the stepped part, using a measuring unit that measures the height of the upper surface of the measurement target object held by the holding table. A width of a measurement region on the upper surface of the stepped part which is measured by the measuring unit in one time measurement is smaller than a width of the stepped part. In the measuring step, the height of the upper surface of the step part is measured at a plurality of measurement positions having different distances from the outer periphery of the measurement target object.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a measurement method and a measurement device for measuring the height of the upper surface of a stepped portion in a measurement object having a stepped portion provided on the outer periphery of the surface side, and a processing method for processing a workpiece to provide a stepped portion on the outer periphery of the workpiece and measuring the height of the upper surface of the stepped portion.

Background Art

[0002] In the manufacturing process of device chips, a disk-shaped wafer in which devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are formed in a plurality of regions partitioned by a plurality of division planned lines (streets) intersecting each other is used. By dividing this wafer along the division planned lines, a plurality of device chips each having a device can be obtained. The device chips are mounted on various electronic devices such as mobile phones and personal computers.

[0003] In recent years, there has been a remarkable trend towards miniaturization of electronic devices, and there has been an increasing demand for thinning of device chips. Therefore, before dividing the wafer, it is ground from the back side with a grinding device to thin it to a predetermined finish thickness, and the thinned wafer is divided. In this case, finally, thin device chips can be obtained.

[0004] A chamfered portion with corners removed is formed on the outer peripheral portion of the wafer. When a part of the chamfered portion is removed when the wafer is thinned, a knife-edge-like sharp shape appears, and the wafer is easily damaged. Therefore, before grinding the wafer, edge trimming processing is performed in which the outer peripheral portion of the wafer is cut with a cutting device from the surface side to a depth exceeding the finish thickness to partially remove the chamfered portion (see Patent Document 1 and Patent Document 2). When the edge trimming process is performed, a stepped portion is formed along the outer periphery on the surface side of the wafer.

Prior Art Documents

Patent Documents

[0005] Patent Document 1 Japanese Patent Application Laid-Open No. 2000-173961 Patent Document 2 Japanese Patent Application Laid-Open No. 2010-245167 Summary of the Invention Problems to be Solved by the Invention

[0006] The cutting blade is composed of abrasive grains and a binder for dispersing and fixing the abrasive grains, and the abrasive grains are exposed from the binder on the outer periphery of the cutting blade. When cutting a plurality of wafers successively, the binder of the cutting blade is consumed, and some of the abrasive grains protrude greatly to the outer periphery, and the wafer is deeply cut at the portion where the protruding abrasive grains come into contact. Then, variations in height reflecting the protruding state of the abrasive grains occur on the upper surface of the step portion formed by edge trimming. That is, the surface of the step portion becomes of low quality.

[0007] In addition, the wear of the cutting edge of the cutting blade particularly progresses easily at the corner portion of the cutting edge, and the corner portion of the cutting edge is gradually rounded as edge trimming is repeated. When edge trimming is further performed with a cutting edge whose corner portion has been rounded, the step portion becomes a curved surface, and the wafer is not removed to a sufficient depth particularly at the inner peripheral portion of the step portion.

[0008] As described above, when edge trimming is repeatedly performed on a plurality of wafers by a cutting device, various problems occur in the cutting edge of the cutting blade. Therefore, there is a demand to measure the height at each location of the step portion formed on the wafer after edge trimming and to check the state of the cutting edge from the measurement results.

[0009] The present invention has been made in view of such problems, and an object thereof is to provide a measuring method and a measuring device for measuring the height of the upper surface of a step portion formed on a measurement object such as a wafer by edge trimming. Or, an object is to provide a processing method for processing a workpiece to provide a step portion on the outer periphery of the workpiece and measuring the height of the upper surface of the step portion. Means for Solving the Problems

[0010] According to one aspect of the present invention, there is provided a measurement method for measuring the height of the upper surface of a step portion provided on the outer periphery on the surface side of an object to be measured, the method including: a holding step of holding the back surface side of the object to be measured with a holding table so as to expose the step portion upward; and a measurement step of measuring the height of the upper surface of the step portion of the object to be measured held by the holding table with a measurement unit. In a single measurement, the width of the measurement region on the upper surface of the step portion to be measured by the measurement unit is smaller than the width of the step portion. In the measurement step, the height of the upper surface of the step portion is measured at a plurality of measurement positions having different distances from the outer periphery of the object to be measured.

[0011] Preferably, in the measurement step, while relatively swinging the holding table and the measurement unit in a direction from the center of the object to be measured toward the outer periphery and in a direction from the outer periphery toward the center of the object to be measured, the holding table and the measurement unit are relatively moved along the outer periphery of the object to be measured, and the height of the upper surface of the step portion is measured at a plurality of measurement positions.

[0012] Alternatively, preferably, the measurement step includes: a first circumferential direction measurement step of relatively moving the holding table and the measurement unit along the outer periphery of the object to be measured and measuring the height of the upper surface of the step portion at a plurality of measurement positions; a moving step of relatively moving the holding table and the measurement unit in a direction from the center of the object to be measured toward the outer periphery or in a direction from the outer periphery toward the center of the object to be measured after the first circumferential direction measurement step; and a second circumferential direction measurement step of relatively moving the holding table and the measurement unit along the outer periphery of the object to be measured and measuring the height of the upper surface of the step portion at a plurality of measurement positions after the moving step.

[0013] Preferably, the object to be measured is an integrated object obtained by bonding one surface of a disk-shaped wafer and a support surface of a support substrate with a bonding member, and in the measurement step, the height of the upper surface of the step portion formed on the other surface side of the wafer corresponding to the surface side of the object to be measured is measured.

[0014] More preferably, the step portion is formed by cutting a rotating cutting blade into the outer periphery of the object to be measured.

[0015] Also, according to another aspect of the present invention, there is provided a processing method for processing a workpiece, including: a holding step of holding the back surface side of the workpiece with a holding table so that the surface side of the workpiece is exposed upward; a first cutting step of forming a step portion on the workpiece by cutting the outer periphery of the workpiece held by the holding table using a first cutting blade attached to the tip of a rotatable spindle; and a measurement step of measuring the height of the upper surface of the step portion of the workpiece by a measurement unit after the first cutting step, wherein the width of the measurement region on the upper surface of the step portion to be measured by the measurement unit in one measurement is smaller than the width of the step portion, and in the measurement step, the height of the upper surface of the step portion is measured at a plurality of measurement positions having different distances from the outer periphery of the workpiece to obtain information regarding the height of the upper surface of the step portion.

[0016] Preferably, after the measurement step, the method further includes a second cutting step of further cutting the step portion of the workpiece with the first cutting blade or a second cutting blade having a smaller abrasive grain diameter than the abrasive grain diameter included in the first cutting blade, and in the second cutting step, the cutting amount of the first cutting blade or the second cutting blade is determined based on the information obtained in the measurement step.

[0017] According to still another aspect of the present invention, there is provided a measuring device for measuring the height of the upper surface of a step portion provided on the outer periphery on the surface side of an object to be measured, the measuring device including: a holding table having a holding surface and holding the back surface side of the object to be measured placed on the holding surface so as to expose the step portion upward; a measuring unit for measuring the height of the upper surface of the step portion of the object to be measured held by the holding table; and a moving unit for relatively moving the holding table and the measuring unit. The width of the measurement region on the upper surface of the step portion to be measured by the measuring unit in one measurement is smaller than the width of the step portion. The moving unit is controlled to relatively move the holding table and the measuring unit, and the measuring unit measures the height of the upper surface of the step portion at a plurality of measurement positions having different distances from the outer periphery of the object to be measured.

[0018] Preferably, the moving unit is controlled to relatively swing the holding table and the measuring unit in a direction from the center of the object to be measured toward the outer periphery and in a direction from the outer periphery toward the center, and relatively move the holding table and the measuring unit along the outer periphery of the object to be measured, and measure the height of the upper surface of the step portion at a plurality of measurement positions.

[0019] Alternatively, preferably, the moving unit is controlled to move the holding table and the measuring unit along the outer periphery of the object to be measured while the measuring unit measures the height of the upper surface of the step portion, then the moving unit is controlled to relatively move the holding table and the measuring unit in a direction from the center of the object to be measured toward the outer periphery or in a direction from the outer periphery toward the center, and then the moving unit is controlled to move the holding table and the measuring unit along the outer periphery of the object to be measured while measuring the height of the upper surface of the step portion.

[0020] And preferably, the object to be measured is an integrated object in which one surface of a disk-shaped wafer and a support surface of a support substrate are bonded together by a bonding member, and the measuring unit measures the height of the upper surface of the step portion formed on the other surface side of the wafer corresponding to the surface side of the object to be measured.

[0021] More preferably, the stepped portion is formed by causing a rotating cutting blade to cut into the outer periphery of the object to be measured.

Effects of the Invention

[0022] In the measurement method, measurement device, and processing method of a workpiece according to one aspect of the present invention, the width of the measurement region in the stepped portion that the measurement unit measures in one measurement is smaller than the width of the stepped portion. And the measurement unit measures the height of the upper surface of the stepped portion at a plurality of measurement positions with different distances from the outer periphery of the object to be measured. Therefore, the height distribution in the width direction of the stepped portion can be measured.

[0023] Therefore, according to one aspect of the present invention, there is provided a measurement method and a measurement device for measuring the height of the upper surface of a stepped portion formed on an object to be measured, such as a wafer, by edge trimming. Or, there is provided a processing method for processing a workpiece to provide a stepped portion on the outer periphery of the workpiece and measuring the height of the upper surface of the stepped portion.

Brief Description of the Drawings

[0024]

Figure 1

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Mode for Carrying Out the Invention

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, the measurement method according to this embodiment, the object to be measured by the measuring device, and the object to be measured will be described. The object to be measured is also an object to be processed by a cutting device. FIG. 1 is a perspective view schematically showing an example of the object to be measured 1.

[0026] The object to be measured 1 is, for example, a disk-shaped wafer made of a semiconductor material such as silicon, and has surfaces 1a and 1b that are substantially parallel to each other. On the surface 1a of the object to be measured 1, a plurality of division planned lines 3 arranged in a grid pattern so as to intersect each other are set. In each region partitioned by the division planned lines 3 on the surface 1a of the object to be measured 1, devices 5 such as ICs and LSIs are formed respectively. The region where the devices 5 are formed on the surface 1a of the object to be measured 1 is called a device region 7. The outer region surrounding the device region 7 is called an outer peripheral surplus region 9.

[0027] Note that there are no restrictions on the material, structure, size, etc. of the object to be measured 1. For example, the object to be measured 1 may be a substrate made of a semiconductor other than silicon (such as GaAs, InP, GaN, SiC, etc.), sapphire, glass (such as quartz glass, borosilicate glass, etc.), or the like. The object to be measured 1 does not have to be disk-shaped and may be rectangular plate-shaped. Also, there are no restrictions on the type, quantity, shape, structure, size, arrangement, etc. of the device 5, and the device 5 may not be formed on the object to be measured 1.

[0028] If there are corners on the outer periphery 1c of the object to be measured 1, when the object to be measured 1 is impacted at the corners, chipping or cracking is likely to occur. If this chipping or cracking progresses from the outer peripheral surplus region 9 to the device region 7, the device 5 will be damaged. Therefore, chamfering is performed in advance on the outer periphery 1c of the object to be measured 1 to remove the corners, and a rounded chamfered portion is formed. FIG. 3 includes a cross-sectional view showing the chamfered portion formed on the outer periphery 1c of the object to be measured 1.

[0029] When the object to be measured 1 is ground from the back surface 1b side to thin the object to be measured 1 and then divided along the division planned line 3 of the object to be measured 1, a plurality of thin chips (device chips) each having the device 5 are manufactured. For dividing the object to be measured 1, for example, a cutting device having an annular cutting blade or a laser processing device having a laser processing unit for irradiating the object to be measured 1 with a laser beam is used. The device chips manufactured by these processing devices are mounted on various electronic devices such as mobile phones and personal computers.

[0030] However, when the object to be measured 1 having a chamfered portion formed on the outer periphery 1c is ground to be thinned, a knife-edge-shaped sharp shape appears on the outer periphery 1c, and the object to be measured 1 is in a state where it is easily damaged. Therefore, before grinding the object to be measured 1 from the back surface 1b side, edge trimming is performed in which the outer periphery 1c of the object to be measured 1 is cut with a cutting device to a depth exceeding the finish thickness from the front surface 1a side to partially remove the chamfered portion. When edge trimming is performed, a stepped portion is formed along the outer periphery 1c on the front surface 1a side of the object to be measured 1.

[0031] Next, a cutting device for cutting the object to be measured 1 to perform edge trimming will be described. FIG. 2 is a perspective view schematically showing the cutting device 2. The cutting device 2 also functions as a measuring device for measuring the height of the upper surface of the step provided on the outer periphery 1c on the surface 1a side of the object to be measured 1, as will be described later.

[0032] The object to be measured 1 to be edge-trimmed by the cutting device (measuring device) 2 is, for example, an annular frame (not shown) having an opening with a diameter larger than the diameter of the object to be measured 1, a tape attached to the annular frame so as to close the opening of the annular frame, and is carried into the cutting device 2 in an integrated state. When the object to be measured 1, the tape, and the annular frame are integrated to form a frame unit, the object to be measured 1 can be handled via the annular frame, making it easier to handle the object to be measured 1. The tape is attached to the back surface 1b side of the object to be measured 1, and the surface 1a side of the object to be measured 1 is exposed upward.

[0033] The cutting device 2 includes a base 4 that supports each component. An opening 4a is formed at the front corner of the base 4, and a cassette support base 8 that moves up and down by an elevating mechanism (not shown) is provided in the opening 4a. A cassette 10 for accommodating a plurality of objects to be measured 1 that are each part of the frame unit is mounted on the upper surface of the cassette support base 8. In FIG. 1, for convenience of explanation, only the outline of the cassette 10 is shown.

[0034] A rectangular opening 4b is formed on the side of the cassette support base 8 such that the longitudinal direction is along the X-axis direction (front-rear direction, machining feed direction). Inside the opening 4b, a ball screw type X-axis moving mechanism (not shown), a table cover 14 and a dust and splash-proof cover 16 that cover the upper part of the X-axis moving mechanism are arranged. The X-axis moving mechanism includes an X-axis moving table (not shown) covered by the table cover 14, and this X-axis moving table is moved in the X-axis direction.

[0035] On the upper surface of the X-axis moving table, a holding table 18 is arranged so as to be exposed from the table cover 14. The holding table 18 has a function of sucking and holding the object 1 to be measured placed on the upwardly exposed holding surface 18a. The holding table 18 is connected to a rotary drive source (not shown) such as a motor and rotates around a rotation axis substantially parallel to the Z-axis direction (vertical direction).

[0036] The holding table 18 includes a porous member 18c having the same diameter as the object 1 to be measured and a frame body covering the porous member 18c. Inside the holding table 18, a suction path (not shown) is formed, one end of which is connected to a suction source (not shown) such as an ejector provided outside the holding table 18. The other end of the suction path reaches the porous member 18c.

[0037] On the holding surface 18a of the holding table 18, the upper surface of the porous member 18c is exposed. The upper surface of the porous member 18c has the same diameter as the object 1 to be measured and is formed substantially parallel to the X-axis direction and the Y-axis direction. Further, around the holding table 18, a plurality of clamps 18b for fixing an annular frame for supporting the object 1 to be measured are provided.

[0038] When holding the object 1 to be measured by the holding table 18, first, the frame unit including the object 1 to be measured is placed on the holding surface 18a of the holding table 18. Then, the suction source and the porous member 18c are connected via the suction path, and a negative pressure is applied to the object 1 to be measured through the tape adhered to the back surface 1b of the object 1 to be measured.

[0039] The cutting device 2 includes a transfer unit (not shown) for transferring the object 1 to be measured to the holding table 18 and the like in a region adjacent to the opening 4b. A temporary placement mechanism for temporarily placing the object 1 to be measured is provided at a position close to the side of the cassette support base 8. The temporary placement mechanism includes, for example, a pair of guide rails 12 that approach and separate while maintaining a state parallel to the Y-axis direction (index feed direction). The pair of guide rails 12 sandwich the object 1 to be measured drawn out from the cassette 10 by the transfer unit and align it to a predetermined position along the X-axis direction.

[0040] The object to be measured 1 fitted at a predetermined position is lifted by a conveying unit and conveyed to a holding table 18. At this time, a pair of guide rails 12 are separated from each other, and the object to be measured 1 is passed between the pair of guide rails 12.

[0041] Above the holding table 18, a first cutting unit 24a for cutting the object to be measured 1 with an annular cutting blade and a second cutting unit 24b are provided. On the upper surface of the base 4, a portal support structure 20 for supporting the first cutting unit 24a and the second cutting unit 24b is arranged so as to straddle the opening 4b.

[0042] On the upper front part of the support structure 20, a moving unit 22a for moving the first cutting unit 24a in the Y-axis direction and the Z-axis direction and a moving unit 22b for moving the second cutting unit 24b in the Y-axis direction and the Z-axis direction are provided. The moving unit 22a includes a Y-axis moving plate 28a, and the moving unit 22b includes a Y-axis moving plate 28b. The two Y-axis moving plates 28a and 28b are slidably mounted on a pair of Y-axis guide rails 26 arranged along the Y-axis direction on the front surface of the support structure 20.

[0043] A nut portion (not shown) is provided on the back surface side (rear surface side) of the Y-axis moving plate 28a, and a Y-axis ball screw 30a substantially parallel to the Y-axis guide rail 26 is screwed into this nut portion. Also, a nut portion (not shown) is provided on the back surface side (rear surface side) of the Y-axis moving plate 28b, and a Y-axis ball screw 30b substantially parallel to the Y-axis guide rail 26 is screwed into this nut portion.

[0044] One end of the Y-axis ball screw 30a is connected to a Y-axis pulse motor 32a. By rotating the Y-axis ball screw 30a with the Y-axis pulse motor 32a, the Y-axis moving plate 28a moves in the Y-axis direction along the Y-axis guide rail 26. Also, one end of the Y-axis ball screw 30b is connected to a Y-axis pulse motor (not shown). By rotating the Y-axis ball screw 30b with the Y-axis pulse motor, the Y-axis moving plate 28b moves in the Y-axis direction along the Y-axis guide rail 26.

[0045] On the surface (front surface) side of the Y-axis moving plate 28a, a pair of Z-axis guide rails 34a are provided along the Z-axis direction, and on the surface (front surface) side of the Y-axis moving plate 28b, a pair of Z-axis guide rails 34b are provided along the Z-axis direction. Also, a Z-axis moving plate 36a is slidably attached to the pair of Z-axis guide rails 34a, and a Z-axis moving plate 36b is slidably attached to the pair of Z-axis guide rails 34b.

[0046] A nut portion (not shown) is provided on the back surface (rear surface) side of the Z-axis moving plate 36a, and a Z-axis ball screw 38a provided along a direction generally parallel to the Z-axis guide rail 34a is screwed into this nut portion. One end of the Z-axis ball screw 38a is connected to a Z-axis pulse motor 40a, and by rotating the Z-axis ball screw 38a with this Z-axis pulse motor 40a, the Z-axis moving plate 36a moves in the Z-axis direction along the Z-axis guide rail 34a.

[0047] A nut portion (not shown) is provided on the back surface (rear surface) side of the Z-axis moving plate 36b, and a Z-axis ball screw 38b provided along a direction generally parallel to the Z-axis guide rail 34b is screwed into this nut portion. One end of the Z-axis ball screw 38b is connected to a Z-axis pulse motor 40b, and by rotating the Z-axis ball screw 38b with this Z-axis pulse motor 40b, the Z-axis moving plate 36b moves in the Z-axis direction along the Z-axis guide rail 34b.

[0048] A first cutting unit 24a is provided at the lower part of the Z-axis moving plate 36a. A camera unit 46a for photographing the object 1 to be measured sucked and held by the holding table 18 is provided at a position adjacent to the first cutting unit 24a. Further, a second cutting unit 24b is provided at the lower part of the Z-axis moving plate 36b. A camera unit 46b for photographing the object 1 to be measured sucked and held by the holding table 18 is provided at a position adjacent to the second cutting unit 24b.

[0049] The positions of the first cutting unit 24a and the camera unit 46a in the Y-axis direction and the Z-axis direction are controlled by the moving unit 22a, and the positions of the second cutting unit 24b and the camera unit 46b in the Y-axis direction and the Z-axis direction are controlled by the moving unit 22b. The positions of the first cutting unit 24a and the second cutting unit 24b are controlled independently of each other.

[0050] An opening 4c is formed at a position on the opposite side of the opening 4a with respect to the opening 4b. A cleaning unit 48 for cleaning the object 1 to be measured is disposed in the opening 4c, and the object 1 to be measured cut on the holding table 18 is cleaned by the cleaning unit 48. The object 1 to be measured cleaned by the cleaning unit 48 is stored in the cassette 10 again.

[0051] The cutting device 2 further includes a controller (control unit) 64 for controlling each component. This controller 64 is constituted by a computer including, for example, a processing device and a storage device, and controls the operations of each element of the cutting device 2 so that the object 1 to be measured is appropriately edge-trimmed. The controller 64 controls, for example, each cutting unit 24a, 24b, the holding table 18, the transfer unit, the camera units 46a, 46b, the cleaning unit 48, each moving unit, and the like.

[0052] The processing device is typically a CPU (Central Processing Unit) that performs various processes necessary to control the above-described elements. The storage device includes, for example, a main storage device such as a DRAM (Dynamic Random Access Memory) and an auxiliary storage device such as a hard disk drive or a flash memory. The functions of the controller 64 are realized, for example, by the processing device operating according to a program (software) stored in the storage device. However, the controller 64 may be realized by hardware only.

[0053] Hereinafter, each cutting unit 24a, 24b will be described in more detail. FIG. 4 is a cross-sectional view schematically showing the object to be measured 1 cut by the first cutting unit 24a. The first cutting unit 24a is used for edge trimming that cuts the object to be measured 1 along the outer periphery 1c to remove a part of the chamfered portion. In FIG. 4 and the like, the clamp 18b of the holding table 18, the camera unit 46a, the annular frame, the tape, and the like are omitted.

[0054] The first cutting unit 24a includes a spindle 50a along the Y-axis direction and a rotational drive source (not shown) such as a motor connected to the base end side of the spindle 50a. An annular first cutting blade 56a is fixed to the tip of the spindle 50a via a flange mechanism 52a.

[0055] The first cutting blade 56a is a cutting blade called a hub type that has, for example, an annular base 58a formed of a material such as aluminum with an insertion hole formed in the center, and a cutting edge 60a fixed to the outer periphery of the base 58a. However, the first cutting blade 56a is not limited to the hub type.

[0056] On the outer periphery of the base 58a, a cutting edge (grinding wheel portion) 60a including innumerable abrasive grains and a binder (bond) for dispersedly fixing the abrasive grains is fixed. For example, the abrasive grains are formed of materials such as diamond and cubic boron nitride (cBN), and the binder is a nickel plating layer or the like. The blade thickness of the first cutting blade 56a used for edge trimming is preferably determined according to the width of the stepped portion formed on the object to be measured 1, and for example, it is preferably 2 mm or more. However, the blade thickness of the first cutting blade 56a is not limited to this.

[0057] Insert a boss portion (not shown) protruding in the Y-axis direction of the flange mechanism 52a into the insertion hole of the base 58a, bring the first cutting blade 56a into contact with the flange surface of the flange mechanism 52a, and tighten the fixing nut 54a at the tip of the boss portion. Then, the first cutting blade 56a can be fixed to the tip of the spindle 50a. Further, the first cutting unit 24a includes a pair of cutting fluid supply nozzles 62a disposed so as to sandwich the lower portion of the first cutting blade 56a fixed to the tip of the spindle 50a.

[0058] When the rotation drive source is operated to rotate the spindle 50a, the first cutting blade 56a can be rotated. When the rotating first cutting blade 56a is cut into the object to be measured 1 sucked and held by the holding table 18, the object to be measured 1 can be cut. At this time, a cutting fluid such as pure water is sprayed from the cutting fluid supply nozzle 62a onto the object to be measured 1 and the first cutting blade 56a, and the machining chips and frictional heat generated by cutting are removed by the cutting fluid.

[0059] FIG. 8 is a cross-sectional view schematically showing the object to be measured 1 cut by the second cutting unit 24b. In FIG. 8, the clamp 18b, the camera unit 46b, the annular frame, the tape, etc. of the holding table 18 are omitted. The second cutting unit 24b is used, for example, to further cut the upper surface of the stepped portion formed on the outer periphery 1c of the object to be measured 1 by the first cutting unit 24a. The second cutting unit 24b is configured in the same manner as the first cutting unit 24a. Therefore, a part of the description of the second cutting unit 24b is omitted.

[0060] The second cutting unit 24b includes a spindle 50b along the Y-axis direction and a rotational drive source (not shown) such as a motor connected to the proximal end side of the spindle 50b. An annular second cutting blade 56b is fixed to the tip of the spindle 50b via a flange mechanism 52b. The second cutting unit 24b includes a pair of cutting fluid supply nozzles 62b disposed so as to sandwich the lower part of the second cutting blade 56b fixed to the tip of the spindle 50b.

[0061] The second cutting blade 56b is a cutting blade called a hub type, which has, for example, an annular base 58b formed of a material such as aluminum and having an insertion hole formed in the center, and a cutting edge 60b fixed to the outer periphery of the base 58b. However, the second cutting blade 56b is not limited to the hub type. A cutting edge (grinding wheel portion) 60b including innumerable abrasive grains and a binder (bond) for dispersedly fixing the abrasive grains is fixed to the outer periphery of the base 58b.

[0062] The blade thickness of the second cutting blade 56b used for edge trimming is preferably determined according to the width of the stepped portion formed on the object to be measured 1, and for example, it is preferably 2 mm or more. However, the blade thickness of the second cutting blade 56b is not limited to this.

[0063] It is preferable that the diameter of the abrasive grains included in the cutting edge 60b of the second cutting blade 56b is smaller than the diameter of the abrasive grains included in the cutting edge 60a of the first cutting blade 56a. However, this does not mean that all of the diameters of the abrasive grains included in the cutting edge 60b of the second cutting blade 56b are smaller than any of the abrasive grains included in the cutting edge 60a of the first cutting blade 56a. As a method for comparing the diameters of the abrasive grains, for example, a method of comparing the average particle diameters can be considered. Furthermore, the magnitude relationship between the diameters of the abrasive grains included in the cutting edges 60a and 60b may be estimated from the results when the object to be measured 1 is cut with the cutting edges 60a and 60b.

[0064] For example, when cutting the object to be measured 1 with a cutting blade having cutting edges containing abrasive grains with a relatively large particle size, the object to be measured 1 can be cut at a relatively high speed. On the other hand, on the surface of the cutting marks formed on the object to be measured 1, an uneven shape with a relatively large height difference is likely to occur. Conversely, when cutting the object to be measured 1 with a cutting blade having cutting edges containing abrasive grains with a relatively small particle size, it is difficult to cut the object to be measured 1 at a high speed. On the other hand, on the surface of the cutting marks formed on the object to be measured 1, the height difference of the uneven shape that appears becomes relatively small.

[0065] When using the first cutting blade 56a and the second cutting blade 56b in the cutting device 2, it is preferable to first use the first cutting blade 56a to quickly form the stepped portion, and then use the second cutting blade 56b to cut the upper surface of the stepped portion to improve the flatness of the upper surface of the stepped portion.

[0066] However, two cutting blades having the same performance may be mounted on the cutting device 2. That is, a second first cutting blade 56a may be mounted on the cutting device 2 instead of the second cutting blade 56b. Further, the cutting device 2 does not necessarily need to include two cutting units 24a and 24b, and may include one cutting unit.

[0067] In the cutting device 2, the object to be measured 1 carried out from the cassette 10 and whose position is adjusted by the guide rail 12 is placed on the holding table 18 by the conveying unit, and the object to be measured 1 is sucked and held by the holding table 18. Then, the positions of the regions to be cut on the object to be measured 1 are confirmed by the camera units 46a and 46b.

[0068] Then, while moving the holding table 18, the moving units 22a and 22b are operated, and the rotating cutting blades 56a and 56b are cut into the outer periphery 1c of the object to be measured 1. At this time, cutting fluid is supplied from the cutting fluid supply nozzles 62a and 62b to the object to be measured 1 and the like. FIG. 4 is a cross-sectional view schematically showing the state in which the first cutting blade 56a cuts the object to be measured 1.

[0069] Next, the holding table 18 is rotated by a rotation amount of one rotation or more around the rotation axis intersecting the holding surface 18a, and the object to be measured 1 is cut along the outer periphery 1c. As a result, a stepped portion is formed on the outer periphery 1c of the object to be measured 1. FIG. 5 includes a cross-sectional view schematically showing the object to be measured 1 having the stepped portion 11 formed along the outer periphery 1c. Thereafter, the object to be measured 1 is carried out from the holding table 18, the object to be measured 1 is washed by the washing unit 48, and the object to be measured 1 is accommodated in the cassette 10. Thus, the processing of the object to be measured 1 by the cutting device 2 is completed.

[0070] Here, in the cutting edges 60a and 60b of the cutting blades 56a and 56b, as described above, the abrasive grains protrude from the binder, and when the object to be measured 1 is cut with the cutting edges 60a and 60b, the state of the cutting edges 60a and 60b changes. Then, there may be a large variation in height along the width direction on the upper surface 13 of the stepped portion 11 formed by edge trimming. That is, the upper surface 13 of the stepped portion 11 may be of low quality.

[0071] Further, the wear of the cutting edges 60a and 60b of the cutting blades 56a and 56b particularly progresses easily at the corners of the cutting edges 60a and 60b, and this corner is gradually rounded as edge trimming is repeated. When edge trimming is further performed with the cutting edges 60a and 60b having rounded corners, the stepped portion 11 becomes a curved surface on the radially inner side, and the object to be measured 1 is not removed to a sufficient depth particularly at the inner peripheral portion of the stepped portion 11.

[0072] Thus, when edge trimming is successively performed on a plurality of objects to be measured 1 by the cutting device 2, various problems occur in the cutting edges 60a and 60b of the cutting blades 56a and 56b. Therefore, after edge trimming is performed, there is a desire to measure the height at each location of the upper surface 13 of the stepped portion 11 formed on the object to be measured 1 and to check the state of the cutting edges 60a and 60b from the measurement results. In particular, there is a desire to measure in detail the height distribution in the width direction of the stepped portion 11.

[0073] Therefore, the cutting device (measurement device) 2 further includes a measurement unit that measures the height of the upper surface of the step portion 11 of the object 1 to be measured held by the holding table 18. Then, the measurement unit measures the height of the upper surface 13 of the step portion 11 at a plurality of measurement positions of the step portion 11. Hereinafter, the cutting device (measurement device) 2 will be further described centering on the configuration that contributes to the measurement of the height of the upper surface 13 of the step portion 11.

[0074] FIG. 5 schematically shows a measurement unit 70 that measures the height of the upper surface 13 of the step portion 11. The measurement unit 70 may be supported, for example, by moving plates 36a and 36b that support the cutting units 24a and 24b and the camera units 46a and 46b. Then, the measurement unit 70 may be movable together with the cutting units 24a and 24b and the camera units 46a and 46b by operating the moving units 22a and 22b.

[0075] Furthermore, when the above-described X-axis moving mechanism is operated to move the holding table 18 along the X-axis direction, the relative position between the holding table 18 and the measurement unit 70 changes. Also, when a rotation driving source for rotating the holding table 18 is operated, the measurement area of the measurement unit 70 in the object 1 to be measured held by the holding table 18 is moved. That is, the moving units 22a and 22b, the X-axis moving mechanism, and this rotation driving source have a function as a moving mechanism that relatively moves the holding table 18 (object 1 to be measured) and the measurement unit 70.

[0076] The measurement unit 70 includes, for example, a non-contact height measuring instrument 72. As a typical example of the non-contact height measuring instrument 72, a measuring instrument sold under the product name "NCG" by DISCO Corporation can be cited. This measuring instrument projects a laser beam having a wavelength of about 1 μm toward the object 1 to be measured, receives the interference wave between the reflected light reflected from the upper surface of the object 1 and the reflected light reflected from the lower surface of the object 1, and thereby measures the thickness of the object 1 to be measured.

[0077] The thickness (thickness distribution) at each location of the object 1 to be edge-trimmed before edge trimming is known. Therefore, by subtracting the thickness of the object 1 obtained by measurement from the thickness of the original object 1, the cutting depth in edge trimming can be calculated. Then, when measuring the thickness of the object 1 at the measurement location set on the step portion 11, the height of the upper surface 13 of the step portion 11 can be calculated from the original thickness of the object 1 at the measurement location. The height of the upper surface 13 of the step portion 11 at the measurement location is calculated by, for example, the controller 64.

[0078] Note that the measurement unit 70 may be able to change the spot diameter of the laser light projected from the height measuring device 72 onto the upper surface 13 of the step portion 11, that is, the size of the measurement area. Also, the width of the measurement area in the step portion 11 that the measurement unit 70 measures in one measurement is preferably smaller than the width of the step portion 11. When the width of the step portion 11 (the length in the radial direction of the object 1) is about 3 mm to 5 mm, the width of the measurement area is preferably about 1 mm.

[0079] If the width of the measurement area is larger than the width of the step portion 11, an area other than the upper surface 13 of the step portion 11 will be included in the measurement area. Therefore, the obtained measurement value will not appropriately reflect the state of the step portion 11. That is, since the width of the measurement area (spot diameter) of the measurement unit 70 is smaller than the width of the step portion 11, highly accurate measurement of the height of the upper surface 13 by the measurement unit 70 becomes possible.

[0080] Note that the height measuring device 72 of the measurement unit 70 is not limited to one that projects laser light onto the object 1. For example, the height measuring device 72 may be a back pressure sensor. The back pressure sensor has an air ejection port for blowing air onto the object 1, ejects air from the ejection port onto the object 1, and detects the pressure change generated by the reflection of the air by the object 1. Since this pressure change reflects the distance between the ejection port and the air ejection area (measurement area), the height of the measurement area can be calculated based on the pressure change.

[0081] The configuration of the back pressure sensor that can be used in the measurement unit 70 will be described in more detail. In the back pressure sensor, the ejection nozzle is connected to the air supply source via the first path. On the other hand, a second path is also connected to the air supply source, and the second path leads to the atmosphere. The gas is supplied from the air supply source to the first path and the second path at an equal ratio. A differential pressure sensor is connected between the first path and the second path. This differential pressure sensor includes a diaphragm that is displaced according to the difference between the pressure in the first path and the pressure in the second path. In the differential pressure sensor, an electrical signal (voltage value) corresponding to the displacement amount of the diaphragm is output.

[0082] The ejection nozzle is oriented in a direction such that the ejection port at the tip faces the object to be measured 1. When the measurement unit 70 is lowered, the ejection port of the ejection nozzle approaches the object to be measured 1. If there is no obstacle in the ejection direction of the air from the ejection port of the ejection nozzle, the first path will also be released to the atmosphere in the same way as the second path. Therefore, the pressure in the first path and the pressure in the second path become equal, the diaphragm of the differential pressure sensor is in an equilibrium state, and a predetermined electrical signal (voltage value) is output from the differential pressure sensor.

[0083] On the other hand, when the ejection port of the ejection nozzle approaches the object to be measured 1, the pressure in the first path changes due to the air ejected from the ejection port being reflected by the object to be measured 1. Therefore, the diaphragm is no longer in an equilibrium state, and an electrical signal (voltage value) corresponding to the distance between the ejection port and the object to be measured 1 is output from the differential pressure sensor.

[0084] If the relationship between the electrical signal (voltage value) output from the differential pressure sensor and the distance from the ejection port of the ejection nozzle to the object to be measured 1 has been acquired in advance, the distance between the ejection port and the measurement area of the object to be measured 1 can be obtained based on the electrical signal (voltage value) output from the differential pressure sensor and this relationship. For example, this relationship may be registered in advance in the storage device (storage unit) of the controller (control unit) 64. Then, the controller 64 calculates the height of the upper surface 13 of the stepped portion 11 from the electrical signal (voltage value) output from the differential pressure sensor and this relationship.

[0085] Next, a procedure for performing edge trimming on the cutting device (measurement device) 2 to form a stepped portion 11 on the object to be measured 1 and measuring the height of the upper surface 13 of the stepped portion 11 will be described. The following description is an explanation of a processing method with the object to be measured 1 as the workpiece. And this processing method includes a measuring method for measuring the height of the upper surface 13 of the stepped portion 11 provided on the outer periphery 1c on the surface 1a side of the object to be measured 1. FIG. 12(C) is a flowchart showing the flow of each step of the processing method of the workpiece according to the present embodiment.

[0086] In the processing method of the workpiece shown in FIG. 12(C), a holding step S40 is performed in which the back surface 1b side of the workpiece (object to be measured 1) is held by the holding table 18 so that the surface 1a side of the workpiece (object to be measured 1) is exposed upward.

[0087] In the holding step S40, first, a cassette 10 that houses a frame unit in which the object to be measured 1, a tape, and an annular frame are integrated is carried to the cassette support base 8. Then, the object to be measured 1 (frame unit) is pulled out from the cassette 10, placed on the holding surface 18a of the holding table 18, and the object to be measured 1 is sucked and held by the holding table 18 via the tape.

[0088] FIG. 3 is a cross-sectional view schematically showing the object to be measured 1 held by the holding table 18. In each figure, the tape and the annular frame included in the frame unit are omitted. When the object to be measured 1 is sucked and held by the holding table 18, the surface 1a side of the object to be measured 1 is exposed upward.

[0089] Next, a first cutting step S50 is performed. In the first cutting step S50, the outer periphery 1c of the workpiece (object to be measured 1) held by the holding table 18 is cut using the first cutting blade 56a attached to the tip of the rotatable spindle 50a. Thereby, a stepped portion 11 is formed on the workpiece (object to be measured 1). That is, edge trimming of the object to be measured 1 is performed. FIG. 4 is a cross-sectional view schematically showing the object to be measured 1 cut by the first cutting blade 56a.

[0090] In the first cutting step S50, for example, the first cutting unit 24a is used. First, the camera unit 46a images the object to be measured 1 to detect the position of the outer periphery 1c of the object to be measured 1. Then, the positions of the first cutting unit 24a and the holding table 18 are adjusted so that the cutting edge 60a of the first cutting blade 56a is positioned above the outer periphery 1c of the object to be measured 1.

[0091] Next, the rotation of the first cutting blade 56a is started by starting the rotation of the spindle 50a, and the first cutting unit 24a is lowered until the lowermost end of the cutting edge 60a reaches a depth exceeding the finish thickness from the surface 1a of the object to be measured 1, and the cutting edge 60a is cut into the object to be measured 1. For example, when the thickness of the object to be measured 1 is 700 μm, it is preferable to reach a position about 300 μm below the surface 1a of the object to be measured 1 at the lower end of the first cutting blade 56a.

[0092] With the first cutting blade 56a cut into the chamfered portion, the holding table 18 is rotated by 360° or more around the table rotation axis perpendicular to the holding surface 18a. Then, the object to be measured 1 is cut along the outer periphery 1c and the chamfered portion is partially removed, and an annular stepped portion 11 (see FIG. 5 etc.) is formed on the object to be measured 1.

[0093] Then, after the first cutting step S50, a measurement step S60 is performed. In the measurement step S60, the height of the upper surface 13 of the stepped portion 11 of the workpiece (object to be measured 1) is measured by the measurement unit 70. FIG. 5 is a cross-sectional view schematically showing the object to be measured 1 in the measurement step S60. For example, the measurement step S60 is performed on the holding table 18 following the first cutting step S50.

[0094] For example, when the measuring unit 70 includes a height measuring device 72 that irradiates the object 1 to be measured with a laser beam 74 to measure the thickness of the object 1 to be measured, while relatively moving the height measuring device 72 and the workpiece (object 1 to be measured), the laser beam 74 is successively irradiated onto a plurality of measurement regions. In particular, in the measurement step S60, the height of the upper surface 13 of the stepped portion 11 is measured at a plurality of measurement positions that are different in distance from the outer periphery 1c of the workpiece (object 1 to be measured).

[0095] FIG. 6 is a plan view schematically showing an example of the movement locus of the measurement region 76 in the measurement step S60. For example, in the measurement step S60, while swinging the measurement region along the radial direction 15 of the object 1 to be measured in the stepped portion 11 and moving the measurement region in the circumferential direction 17, the measurement is carried out. FIG. 6 shows a part of the surface 1a side of the object 1 to be measured in which the stepped portion 11 is formed.

[0096] That is, while relatively swinging the holding table 18 and the measuring unit 70 in the direction from the center to the outer periphery 1c of the object 1 to be measured and in the direction from the outer periphery 1c to the center, the holding table 18 and the measuring unit 70 are relatively moved along the outer periphery 1c of the object 1 to be measured. Then, the height of the upper surface 13 of the stepped portion 11 is measured at a plurality of measurement positions (positions of the measurement region 76). Note that the movement of the measurement region 76 may be temporarily stopped during the measurement.

[0097] More specifically, while swinging the measuring unit 70 in the Y-axis direction by the moving units 22a and 22b (see FIG. 1), the holding table 18 is rotated around a rotation axis perpendicular to the holding surface 18a. Then, in the stepped portion 11 of the object 1 to be measured, the measurement region 76 moves as shown in FIG. 7.

[0098] In this case, the position (measurement position) of the measurement region 76 on the upper surface 13 of the stepped portion 11 of the object 1 to be measured can be specified by the position of the measuring unit 70 in the Y-axis direction and the rotation angle of the holding table 18. Therefore, when the height of the upper surface 13 of the stepped portion 11 obtained by the measuring unit 70 and the position of the measurement region 76 at the time of measurement are linked and accumulated, the height distribution at various locations on the upper surface 13 of the stepped portion 11 can be obtained.

[0099] In the processing method of the workpiece (the object to be measured 1) according to this embodiment, the width of the measurement region 76 in the step portion 11 to be measured by the measurement unit 70 in one measurement is smaller than the width of the step portion 11 in the radial direction of the object to be measured 1. Therefore, the measurement region 76 can be moved in this way while controlling so that the measurement region 76 does not deviate from the upper surface 13 of the step portion 11. And since the information of the region deviated from the upper surface 13 of the step portion 11 is not reflected in the measurement value, the height distribution at each place on the upper surface 13 is derived with high accuracy.

[0100] Note that the movement mode of the measurement region 76 in the measurement step S60 is not limited to the mode shown in FIG. 6. FIG. 7 is a plan view schematically showing another example of the movement locus of the measurement region 76 in the measurement step S60. For example, in the measurement step S60, height measurement is performed while moving the measurement position (the position of the measurement region 76) along the outer periphery 1c of the workpiece (the object to be measured 1) in the step portion 11. Next, the measurement position is moved in the radial direction of the object to be measured 1, and further, height measurement is performed while moving the measurement position along the outer periphery 1c of the object to be measured 1.

[0101] Particularly in the example shown in FIG. 7, height measurement of the upper surface 13 of the step portion 11 is performed at a measurement position relatively far from the center of the object to be measured 1, and the measurement is repeated while rotating the holding table 18 around the rotation axis perpendicular to the holding surface 18a. Thereby, the height of the upper surface 13 of the step portion 11 is measured at a plurality of measurement regions 76 separated from the center of the object to be measured 1 by a predetermined distance.

[0102] Next, the measurement region 76 is brought closer to the center of the object to be measured 1, and the measurement is repeated while rotating the holding table 18 around the rotation axis perpendicular to the holding surface 18a. Thereby, the height of the upper surface 13 of the step portion 11 is measured at a plurality of measurement regions 76 separated from the center of the object to be measured 1 by another predetermined distance.

[0103] In this way, on the upper surface 13 of the stepped portion 11, while alternately repeating the movement of the measurement region 76 along the circumferential direction 17 and the movement of the measurement region 76 along the radial direction 15, the height of the upper surface 13 is measured at various positions of the stepped portion 11. Then, the height distribution of each position of the upper surface 13 is derived with high precision.

[0104] The height measurement of the upper surface 13 of the stepped portion 11 in the example shown in FIG. 7 will be described from another perspective. In the measurement step S60 in the example shown in FIG. 7, each step shown in the flowchart of FIG. 12(B) is performed. That is, the first circumferential direction measurement step S21, the movement step S22, and the second circumferential direction measurement step S23 are performed.

[0105] In the first circumferential direction measurement step S21, while relatively moving the holding table 18 and the measurement unit 70 along the outer periphery 1c of the object to be measured 1 (along the circumferential direction 17 of the object to be measured 1), the height of the upper surface 13 of the stepped portion 11 is measured at a plurality of measurement positions. Note that the relative movement of the holding table 18 and the measurement unit 70 along the outer periphery 1c of the object to be measured 1 includes one or both of them rotating, that is, the direction changing, and in that case, one or both of them moving from the original position also includes. Furthermore, it also includes one or both of them rotating in place. Typically, it refers to the holding table 18 rotating around a rotation axis perpendicular to the holding surface 18a, but is not limited thereto.

[0106] Then, in the movement step S22 performed after the first circumferential direction measurement step S21, the holding table 18 and the measurement unit 70 are relatively moved in the direction from the center of the object to be measured 1 to the outer periphery 1c, or in the direction from the outer periphery 1c to the center. That is, both are relatively moved along the radial direction 15.

[0107] In the second circumferential direction measurement step S23 after the movement step S22, while relatively moving the holding table 18 and the measurement unit 70 along the outer periphery 1c of the object to be measured 1 (along the circumferential direction 17 of the object to be measured 1), the height of the upper surface 13 of the stepped portion 11 is measured at a plurality of measurement positions. Note that after the second circumferential direction measurement step S23, a movement step and a circumferential direction measurement step may be alternately repeated further.

[0108] Note that the position (measurement position) of the measurement area 76 in the measurement step S60 may be moved in still other manners. In any case, in the processing method of the workpiece (object to be measured 1) according to the present embodiment, in the measurement step S60, the height of the upper surface 13 of the stepped portion 11 is measured at a plurality of measurement positions having different distances from the outer periphery 1c of the workpiece. Therefore, the height distribution in the width direction of the upper surface 13 of the stepped portion 11 can be obtained in detail.

[0109] When the workpiece (object to be measured 1) is cut along the outer periphery 1c in the first cutting step S50 to form the stepped portion 11, variations in height along the width direction reflecting the state of the cutting edge 60a of the first cutting blade 56a occur on the upper surface 13 of the stepped portion 11. Then, when the measurement step S60 is performed, information regarding this height variation on the upper surface 13 of the stepped portion 11 is obtained, and the state of the cutting edge 60a can also be determined from this information.

[0110] When it is determined that the state of the cutting edge 60a is unsuitable for subsequent edge trimming, the first cutting blade 56a may be replaced. Thereby, high-quality edge trimming can be performed in the cutting device 2.

[0111] Further, by performing a finishing process according to the state of the height variation on the upper surface 13 of the stepped portion 11 thereafter, the quality of the upper surface 13 of the stepped portion 11 may be improved. That is, in the processing method of the workpiece (object to be measured 1) according to the present embodiment, a second cutting step S70 may be performed after the measurement step S60. In other words, the processing method of the workpiece (object to be measured 1) according to the present embodiment may further include a second cutting step S70 that is performed after the measurement step S60.

[0112] FIG. 8 is a cross-sectional view schematically showing the workpiece (the object to be measured 1) in the second cutting step S70. In the second cutting step S70, it is preferable to use the second cutting unit 24b. The diameter of the abrasive grains included in the cutting edge 60b of the second cutting blade 56b is smaller than the diameter of the abrasive grains included in the cutting edge 60a of the first cutting blade 56a. Therefore, the second cutting blade 56b can finish the upper surface 13 of the stepped portion 11 with high quality. However, the first cutting unit 24a may be used in the second cutting step S70.

[0113] In the second cutting step S70 performed after the measurement step S60, the stepped portion 11 of the workpiece (the object to be measured 1) is further cut by the second cutting blade 56b in which the diameter of the included abrasive grains is smaller than the diameter of the abrasive grains included in the first cutting blade 56a.

[0114] Then, in the second cutting step S70, based on the information regarding the height of the upper surface 13 of the stepped portion 11 acquired in the measurement step S60, conditions such as the cutting amount of the second cutting blade 56b with respect to the stepped portion 11 may be determined. For example, in the second cutting step S70, since the cutting amount of the second cutting blade 56b is determined to be a necessary and sufficient amount for finishing the upper surface 13 of the stepped portion 11 with high quality, the upper surface 13 of the stepped portion 11 can be finished quickly.

[0115] When the first cutting blade 56a of the first cutting unit 24a is used in the second cutting step S70, it is not necessary to perform cutting under the same conditions in the first cutting step S50 and the second cutting step S70. In the second cutting step S70, it is preferable to change the conditions such as the rotational speed of the cutting blade 56a and the rotational speed of the holding table 18 to settings different from those in the first cutting step S50 and perform edge trimming. In particular, the cutting amount of the first cutting blade 56a with respect to the stepped portion 11 may be determined based on the information regarding the height of the upper surface 13 of the stepped portion 11.

[0116] So far, the procedure of performing edge trimming in the cutting device (measurement device) 2 to form the step portion 11 on the object to be measured 1 and measuring the height of the upper surface 13 of the step portion 11 has been described. That is, the processing method with the object to be measured 1 as the workpiece has been described. However, it is not necessary to perform edge trimming in the cutting device (measurement device) 2.

[0117] For example, for the object to be measured 1 on which edge trimming has been performed externally, the cutting device (measurement device) 2 may measure the height of the upper surface 13 of the step portion 11. Also, the measurement of the height of the upper surface 13 of the step portion 11 of the object to be measured 1 on which edge trimming has been performed by the cutting device 2 equipped with the cutting units 24a and 24b does not have to be performed by the cutting device 2 and may be performed by a measurement device not equipped with the cutting units 24a and 24b.

[0118] Next, a measurement method for measuring the height of the upper surface 13 of the step portion 11 provided on the outer periphery 1c on the surface 1a side of the object to be measured 1 will be described. This measurement method performs a part of a plurality of steps described in the above-described processing method of the workpiece. Therefore, for each step described below, the above description can be appropriately referred to. FIG. 12(A) is a flowchart showing the flow of each step of this measurement method of the object to be measured.

[0119] First, a holding step S10 is performed in which the back surface 1b side of the object to be measured 1 is held by the holding table 18 so that the step portion 11 is exposed upward. This holding step S10 is performed in the same manner as the holding step S40 in the above-described processing method of the workpiece. This step portion 11 is formed in advance by cutting a rotating cutting blade into the outer periphery 1c of the object to be measured 1. However, the step portion 11 may be formed by a processing unit other than the cutting blade.

[0120] In the holding step S10, the object to be measured 1 on which edge trimming has been performed and the step portion 11 is formed is placed on the holding table 18. At this time, the back surface 1b of the object to be measured 1 is opposed to the holding surface 18a of the holding table 18 so that the step portion 11 is exposed upward.

[0121] Next, a measurement step S20 of measuring the height of the upper surface 13 of the step portion 11 of the object 1 to be measured held by the holding table 18 is performed by a measurement unit 70. FIG. 5 is a cross-sectional view schematically showing the object 1 to be measured in which the height of the upper surface 13 of the step portion 11 is measured in the measurement step S20. This measurement step S20 is performed in the same manner as the measurement step S60 in the above-described processing method of the workpiece.

[0122] In the measurement step S20, the height may be measured at various positions on the upper surface 13 of the step portion 11 while moving the measurement region 76 in a zigzag manner along the outer periphery 1c of the object 1 to be measured on the upper surface 13 of the step portion 11. That is, while relatively swinging the holding table 18 and the measurement unit 70 in the direction from the center of the object 1 to be measured toward the outer periphery 1c and in the direction from the outer periphery 1c to the center, the holding table 18 and the measurement unit 70 are relatively moved along the outer periphery 1c of the object 1 to be measured. Then, the height of the upper surface 13 of the step portion 11 is measured at a plurality of measurement positions.

[0123] Alternatively, in the measurement step S20, as described with reference to FIGS. 7 and 12(B), a first circumferential direction measurement step S21 may be performed, then a movement step S22 may be performed, and then a second circumferential direction measurement step S23 may be performed. That is, while moving the measurement region 76 along the circumferential direction 17 of the object 1 to be measured, the height measurement of the upper surface 13 of the step portion 11 is repeated. Next, the measurement region 76 is moved along the radial direction 15 of the object 1 to be measured, and again, while moving the measurement region 76 along the circumferential direction 17 of the object 1 to be measured, the height measurement of the upper surface 13 of the step portion 11 is repeated.

[0124] More specifically, in the first circumferential direction measurement step S21, while relatively moving the holding table 18 and the measurement unit 70 along the outer circumference 1c of the object 1 to be measured, the height of the upper surface 13 of the step portion 11 is measured at a plurality of measurement positions. In the movement step S22, the holding table 18 and the measurement unit 70 are relatively moved in a direction from the center of the object 1 to be measured toward the outer circumference 1c or in a direction from the outer circumference 1c toward the center. In the second circumferential direction measurement step S23, while relatively moving the holding table 18 and the measurement unit 70 along the outer circumference 1c of the object 1 to be measured, the height of the upper surface 13 of the step portion 11 is measured at a plurality of measurement positions.

[0125] In the measurement method described so far, in one measurement, the width of the measurement region 76 on the upper surface 13 of the step portion 11 to be measured by the measurement unit 70 is made smaller than the width in the radial direction 15 of the step portion 11. Therefore, in the measurement step S20, the height of the upper surface 13 of the step portion 11 can be measured at a plurality of measurement positions (positions of the measurement region 76) having different distances from the outer circumference 1c of the object 1 to be measured. Thereby, highly accurate information regarding the height distribution of the upper surface 13 of the step portion 11 can be obtained.

[0126] And in the measurement method described so far, in order to measure the height of the upper surface 13 of the step portion 11 of the object 1 to be measured in which the step portion 11 is formed in advance, cutting units 24a, 24b, etc. are not used. Therefore, the measurement device for measuring the height of the upper surface 13 of the step portion 11 does not have to include a part of the configuration of the cutting device 2.

[0127] Next, a configuration that the measurement device for measuring the height of the upper surface 13 of the step portion 11 provided on the outer circumference 1c on the surface 1a side of the object 1 to be measured should have will be described. Any of the configurations shown below is a configuration included in the cutting device 2 described with reference to FIG. 2 and the like and has been described, so detailed description of each configuration of the measurement device will be omitted.

[0128] The measuring device includes at least a holding table 18, a measuring unit 70, and a moving unit. The holding table 18 has a holding surface 18a and holds the back surface 1b side of the object 1 to be measured placed on the holding surface 18a so as to expose the step portion 11 upward. The measuring unit 70 measures the height of the upper surface 13 of the step portion 11 of the object 1 to be measured held by the holding table 18.

[0129] The moving unit relatively moves the holding table 18 and the measuring unit 70. More specifically, the moving unit can relatively move the holding table 18 and the measuring unit 70 in the X-axis direction, Y-axis direction, and Z-axis direction perpendicular to each other, and rotate the holding table 18 around an axis perpendicular to the holding surface 18a.

[0130] And, in one measurement, the width of the measurement area 76 on the upper surface 13 of the step portion 11 to be measured by the measuring unit 70 is smaller than the width of the step portion 11 in the radial direction 15 of the object 1 to be measured. Further, the measuring device controls the moving unit to relatively move the holding table 18 and the measuring unit 70, and measures the height of the upper surface 13 of the step portion 11 at a plurality of measurement positions having different distances from the outer periphery 1c of the object 1 to be measured by the measuring unit 70.

[0131] Furthermore, the measuring device may perform the measurement while moving the measurement area 76 on the upper surface 13 of the step portion 11 as described with reference to FIG. 6. That is, the measuring device controls the moving unit to relatively swing the holding table 18 and the measuring unit 70 in the direction from the center of the object 1 to be measured toward the outer periphery 1c and in the direction from the outer periphery 1c toward the center, and relatively move the holding table 18 and the measuring unit 70 along the outer periphery 1c of the object 1 to be measured. Then, the height of the upper surface 13 of the step portion 11 is measured at a plurality of measurement positions.

[0132] Alternatively, as described with reference to FIG. 7, the measuring device may perform measurements while alternately repeating the movement in the circumferential direction 17 and the movement in the radial direction 15 of the measurement region 76. That is, the measuring device controls the moving unit to move the holding table 18 and the measuring unit 70 along the outer periphery 1c of the object to be measured 1, and measures the height of the upper surface 13 of the stepped portion 11 with the measuring unit 70. Next, the moving unit is controlled to relatively move the holding table 18 and the measuring unit 70 in a direction from the center of the object to be measured 1 toward the outer periphery 1c or in a direction from the outer periphery 1c toward the center. Next, the moving unit is controlled to move the holding table 18 and the measuring unit 70 along the outer periphery 1c of the object to be measured 1, and the height of the upper surface 13 of the stepped portion 11 is measured.

[0133] By having the configuration described above, the measuring device can measure the height of the upper surface 13 of the stepped portion 11 of the object to be measured 1. However, the measuring device may have other configurations. When information regarding the distribution of the height of the upper surface 13 of the stepped portion 11 is obtained by the measuring device, the state of the cutting edge of the cutting blade that forms the stepped portion 11 can be specified, and a correction operation of the cutting blade can be performed as necessary. Further, when information regarding the height distribution of the upper surface 13 of the stepped portion 11 is obtained, appropriate conditions can be selected with reference to this information when further treatment is performed on the stepped portion 11.

[0134] Note that the present invention is not limited to the description of the above embodiment, and various modifications can be made. For example, in the above embodiment, the case where the object to be measured 1 on which the stepped portion 11 is formed and the height of the upper surface 13 of the stepped portion 11 is measured is a disk-shaped wafer has been described as an example, but one aspect of the present invention is not limited to this.

[0135] FIG. 9 is a cross-sectional view schematically showing an example of an object to be measured placed on the holding table 18 and held by suction. The object to be measured in this example is an integrated object 19 in which one surface 25b of a disk-shaped wafer 25 and the surface (support surface) 21a of the support substrate 21 are bonded together by a bonding member 23.

[0136] The support substrate 21 of the integrated object 19 has the function of supporting the wafer 25 to be processed. The support substrate 21 is made of, for example, silicon as the base material and has relatively high rigidity. The support substrate 21 is formed in a disk shape substantially the same shape as the wafer 25. Note that the base material of the support substrate 21 may be sapphire, glass, or the like. Also, in the integrated object 19, the center of the support substrate 21 and the center of the wafer 25 are substantially aligned.

[0137] In the integrated object 19, one surface 25b of the wafer 25 and the surface (support surface) 21a of the support substrate 21 are bonded to each other via a bonding member 23 as a bonding surface. Thereby, the other surface 25a of the wafer 25 and the back surface 21b of the support substrate 21 become the exposed surfaces of the integrated object 19. The bonding member 23 is, for example, an adhesive made of an ultraviolet curable resin.

[0138] A plurality of devices such as ICs and LSIs are arranged and formed on the above-mentioned one surface 25b which is the bonding surface of the wafer 25. Then, when the wafer 25 is ground and thinned from the other surface 25a side and the wafer 25 is divided for each device, individual device chips can be manufactured. Note that devices may also be formed on the surface 21a side of the support substrate 21, and the devices formed on the support substrate 21 and the devices formed on the wafer 25 may be electrically connected by a connection path such as a conductive wire passing through the bonding member 23.

[0139] A chamfered portion is formed on the outer periphery 25c of the wafer 25. The wafer 25 is subjected to edge trimming processing while being supported by the support substrate 21. Then, when the surface 25b on which the devices of the wafer 25 are formed faces the support substrate 21, it is desirable that the wafer 25 be removed from the surface 25a to the surface 25b at the outer periphery 25c so that no chamfered portion remains on the outer periphery 25c of the thinned wafer 25.

[0140] However, when the cutting blade is inserted into the outer periphery 25c of the wafer 25, if the cutting depth becomes larger than expected, the cutting blade will cut into the bonding member 23 and the support substrate 21. Therefore, the cutting blade is not inserted into the surface 25b at the outer periphery 25c of the wafer 25, and a stepped portion 11 along the outer periphery 25c is formed on the wafer 25. Thereafter, it is conceivable to precisely remove the remaining stepped portion 11.

[0141] Here, in order to precisely remove the stepped portion 11 formed on the wafer 25, it is necessary to specify the remaining thickness of the wafer 25 in the stepped portion 11, and for this purpose, it is desirable to measure the height of the upper surface 13 of the stepped portion 11. In particular, information regarding the height distribution in the width direction (radial direction) of the stepped portion 11 is desirable. Referring to this information, the removal operation of the stepped portion 11 can be carried out under appropriately selected conditions.

[0142] Hereinafter, a method for processing a workpiece will be described in which a stepped portion 11 is formed on a wafer 25 with an integral object 19 as the workpiece and the height of the upper surface 13 of the stepped portion 11 is measured. The following description includes an explanation of a measuring method in which the integral object 19 with the stepped portion 11 formed thereon is used as the object to be measured and the height of the upper surface 13 of the stepped portion 11 of the object to be measured is measured.

[0143] In this method for processing a workpiece, first, the back surface side (the back surface 21b side of the support substrate 21) of the integral object 19 is held by the holding table 18 so that the surface side (the surface 25a side of the wafer 25) of the integral object 19 is exposed upward (holding step). FIG. 9 is a cross-sectional view schematically showing the integral object 19 sucked and held by the holding table 18 of the cutting device 2.

[0144] Next, by using the first cutting blade 56a mounted on the tip of the rotatable spindle 50a, a step portion 11 is formed on the integrated object 19 (workpiece / object to be measured) held by the holding table 18 by cutting the outer periphery (the outer periphery 25c of the wafer 25) of the integrated object 19 (cutting step). FIG. 10 is a cross-sectional view schematically showing a state in which the outer periphery 25c of the wafer 25 of the integrated object 19 is cut by the first cutting blade 56a. As a result, a step portion 11 is formed on the other surface 25a side of the wafer 25 corresponding to the surface side of the workpiece / object to be measured.

[0145] Thereafter, the height of the upper surface 13 of the step portion 11 of the integrated object 19 (workpiece / object to be measured) is measured by the measurement unit 70 (measurement step). That is, the height of the upper surface 13 of the step portion 11 formed on the other surface 25a side of the wafer 25 corresponding to the surface side of the workpiece / object to be measured is measured. FIG. 11 is a cross-sectional view schematically showing a state in which the height of the upper surface 13 of the step portion 11 formed on the outer periphery 25c of the wafer 25 of the integrated object 19 is measured by the measurement unit 70.

[0146] Also in this method of processing the workpiece, the width of the measurement region 76 on the upper surface 13 of the step portion 11 that the measurement unit 70 measures in one measurement is smaller than the width of the step portion 11. Therefore, when measuring the height of the upper surface 13 of the step portion 11, the height of the upper surface 13 of the step portion 11 can be measured at a plurality of measurement positions having different distances from the outer periphery 25c of the wafer 25 of the integrated object 19 (the outer periphery of the workpiece / object to be measured). As a result, as information regarding the height of the upper surface 13 of the step portion 11, the height distribution of each part of the upper surface 13 of the step portion 11 can be obtained.

[0147] After the height distribution of each part of the upper surface 13 of the step portion 11 formed on the wafer 25 of the integrated object 19 is obtained, for example, further cutting (edge trimming) by a cutting blade may be performed under conditions selected based on the obtained information to remove the step portion 11.

[0148] Alternatively, the step portion 11 may be removed by another method. For example, the step portion 11 may be removed by an etching process using a chemical solution. Even in this case, if the height distribution at various locations on the upper surface 13 of the step portion 11 is obtained, the thickness of the wafer 25 at various locations of the step portion 11 can be specified, and the conditions of the etching process (processing time, chemical solution concentration, etc.) can be appropriately determined.

[0149] In addition, in the above embodiment, the case where the height is measured at various locations on the upper surface 13 of the step portion 11 mainly formed on the disk-shaped wafer has been described. However, the object to be measured / processed is not limited to the disk-shaped wafer. For example, the object to be measured / processed may be a rectangular substrate. According to one aspect of the present invention, the height of the upper surface of the step portion formed along the outer periphery of the rectangular substrate can be measured to obtain information regarding the height distribution at various locations.

[0150] Note that the structure, method, etc. according to the above embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

Explanation of Reference Numerals

[0151] 1 Object to be measured 1a Surface 1b Back surface 1c Outer periphery 3 Scheduled division line 5 Device 7 Device region 9 Outer peripheral surplus region 11 Step portion 13 Upper surface 15 Radial direction 17 Circumferential direction 19 Integral object 21 Support substrate 21a Surface 21b Back surface 23 Bonding member 25 Wafer 25a, 25b Surfaces 25c Outer periphery 2 Cutting device (measurement device) 4 Base 4a, 4b, 4c Openings 8 Cassette support base 10 Cassette 12 Guide rail 14 Table cover 16 Dust and splash proof cover 18 Holding table 18a Holding surface 18b Clamp 18c Porous member 20 Support structure 22a, 22b Moving unit 24a, 24b Cutting unit 26 Y-axis guide rail 28a, 28b Y-axis moving plate 30a, 30b Y-axis ball screw 32a Y-axis pulse motor 34a, 34b Z-axis guide rail 36a, 36b Z-axis moving plate 38a, 38b Z-axis ball screw 40a, 40b Z-axis pulse motor 46a, 46b Camera unit 48 Cleaning unit 50a, 50b Spindle 52a, 52b Flange mechanism 54a Fixed nut 56a, 56b Cutting blade 58a, 58b Base 60a, 60b Cutting edge 62a, 62b Cutting fluid supply nozzle 64 Controller 70 Measuring unit 72 Height measuring instrument 74 Laser beam 76 Measuring area

Claims

1. A measuring method for measuring the height of the upper surface of a stepped portion provided on the outer periphery on the surface side of an object to be measured, comprising: a holding step of holding the back surface side of the object to be measured with a holding table so as to expose the stepped portion upward; a measuring step of measuring the height of the upper surface of the stepped portion of the object to be measured held by the holding table with a measuring unit for measuring the height of the upper surface of the stepped portion, and the width of the measurement area on the upper surface of the stepped portion to be measured by the measurement unit in one measurement is smaller than the width of the stepped portion, wherein in the measuring step, the height of the upper surface of the stepped portion is measured at a plurality of measuring positions having different distances from the outer periphery of the object to be measured.

2. In the measuring step, while relatively swinging the holding table and the measuring unit in a direction from the center of the object to be measured toward the outer periphery and a direction from the outer periphery toward the center of the object to be measured, the holding table and the measuring unit are relatively moved along the outer periphery of the object to be measured, and the height of the upper surface of the stepped portion is measured at a plurality of measuring positions. The measuring method according to claim 1.

3. The measuring step includes: a first circumferential direction measuring step of measuring the height of the upper surface of the stepped portion at a plurality of measuring positions while relatively moving the holding table and the measuring unit along the outer periphery of the object to be measured; a moving step of relatively moving the holding table and the measuring unit in a direction from the center of the object to be measured toward the outer periphery or a direction from the outer periphery toward the center of the object to be measured after the first circumferential direction measuring step; and a second circumferential direction measuring step of measuring the height of the upper surface of the stepped portion at a plurality of measuring positions while relatively moving the holding table and the measuring unit along the outer periphery of the object to be measured after the moving step. The measuring method according to claim 1.

4. The object to be measured is an integral body in which one surface of a disk-shaped wafer and a support surface of a support substrate are bonded together with a bonding member, wherein in the measuring step, the height of the upper surface of the stepped portion formed on the other surface side of the wafer corresponding to the surface side of the object to be measured is measured. The measuring method according to claim 1.

5. The stepped portion is formed by cutting a rotating cutting blade into the outer periphery of the object to be measured. The measuring method according to any one of claims 1 to 4.

6. A processing method for processing a workpiece, comprising: A holding step of holding the back surface side of the workpiece by a holding table so as to expose the front surface side of the workpiece upward; A first cutting step of forming a stepped portion on the workpiece by cutting the outer periphery of the workpiece held by the holding table using a first cutting blade attached to the tip of a rotatable spindle; After the first cutting step, a measuring step of measuring the height of the upper surface of the stepped portion of the workpiece by a measuring unit that measures the height of the upper surface of the stepped portion; The width of the measurement area on the upper surface of the stepped portion to be measured by the measurement unit in one measurement is smaller than the width of the stepped portion; In the measuring step, the height of the upper surface of the stepped portion is measured at a plurality of measuring positions having different distances from the outer periphery of the workpiece, and information regarding the height of the upper surface of the stepped portion is acquired. A processing method characterized by this.

7. After the measuring step, a second cutting step of further cutting the stepped portion of the workpiece with the first cutting blade or a second cutting blade having a smaller abrasive grain diameter than the abrasive grain diameter included in the first cutting blade is further provided; In the second cutting step, the cutting amount of the first cutting blade or the second cutting blade is determined based on the information obtained in the measuring step. The processing method according to claim 6, characterized by this.

8. A measuring device for measuring the height of the upper surface of a stepped portion provided on the outer periphery of the surface side of an object to be measured, A holding table having a holding surface and holding the back surface side of the object to be measured placed on the holding surface so as to expose the stepped portion upward; A measuring unit that measures the height of the upper surface of the stepped portion of the object to be measured held by the holding table; A moving unit that relatively moves the holding table and the measuring unit; The width of the measurement area on the upper surface of the stepped portion to be measured by the measurement unit in one measurement is smaller than the width of the stepped portion; The moving unit is controlled to relatively move the holding table and the measuring unit, and the measuring unit measures the height of the upper surface of the stepped portion at a plurality of measuring positions having different distances from the outer periphery of the object to be measured. A measuring device characterized by this.

9. Controlling the moving unit to relatively swing the holding table and the measuring unit in a direction from the center of the object to be measured toward the outer periphery and in a direction from the outer periphery toward the center of the object to be measured, and relatively moving the holding table and the measuring unit along the outer periphery of the object to be measured, and measuring the height of the upper surface of the stepped portion at a plurality of measurement positions. The measuring device according to claim 8, characterized in that.

10. Controlling the moving unit to move the holding table and the measuring unit along the outer periphery of the object to be measured, and measuring the height of the upper surface of the stepped portion with the measuring unit. Next, controlling the moving unit to relatively move the holding table and the measuring unit in a direction from the center of the object to be measured toward the outer periphery or in a direction from the outer periphery toward the center of the object to be measured. Next, controlling the moving unit to move the holding table and the measuring unit along the outer periphery of the object to be measured, and measuring the height of the upper surface of the stepped portion. The measuring device according to claim 8, characterized in that.

11. The object to be measured is an integrated object obtained by bonding one surface of a disk-shaped wafer and a support surface of a support substrate with a bonding member. Measuring, with the measuring unit, the height of the upper surface of the stepped portion formed on the other surface side of the wafer corresponding to the surface side of the object to be measured. The measuring device according to claim 8, characterized in that.

12. The stepped portion is formed by cutting a rotating cutting blade into the outer periphery of the object to be measured. The measuring device according to any one of claims 8 to 11, characterized in that.

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