Dicing apparatus and trimming method for dicing apparatus

Abstract

The purpose of the present invention is to provide a dicing apparatus capable of high-precision trimming of a workpiece having devices. The dicing apparatus is provided with a chuck table, a rotation table, a microscope, a displacement sensor, a cutting unit, and a control unit that controls movement of the chuck table, the rotation table, the microscope, and the displacement sensor on the basis of measurement results from the microscope and the displacement sensor. The workpiece includes a plurality of devices disposed in regions partitioned by a plurality of first groove portions extending in the X direction and a plurality of second groove portions extending in the Y direction. The control unit acquires, with respect to a specific portion of prescribed devices positioned outward in the radial direction about the Z axis among the devices on the workpiece, workpiece position information along the entire circumference regarding a normal-direction position at circumferential positions about the Z axis on the basis of the measurement results from the displacement sensor, and causes a blade to cut a step portion recessed in the Z direction in the outer peripheral portion of the workpiece on the basis of the acquired workpiece position information.

Description

Dicing device and trimming method for dicing device

[0001] This application claims priority to Japanese Patent Application No. 2024-057188, filed on March 29, 2024, the contents of which are incorporated herein by reference.

[0002] A dicing machine that divides workpieces such as wafers on which semiconductor elements or electronic components are formed into individual chips is equipped with a blade that is rotated at high speed by a spindle, a chuck table that suction-holds the workpiece, and X, Y, Z, and θ drive units that change the relative position of the chuck table and the blade. This dicing machine performs dicing (cutting) by cutting into the workpiece with the blade while the blade and the workpiece are moved relatively by the respective drive units.

[0003] When ultra-thinning wafers and other workpieces, edge chipping occurs due to the R-shape of the outer periphery, and cracks in the workpiece originating from this can be an issue. To prevent cracks in the workpiece, a trimming process is performed in which the R-shape of the outer periphery, which is the cause of edge chipping, is removed in advance using a blade.

[0004] For a trimmed workpiece, a microscope is used to measure the position of the edge portion at three or more points in the XY plane, and based on the measured positional relationships, the trimming width, the center position of the inner portion formed by trimming, the inner diameter, etc. In order to measure the Z-direction position of the surface of a trimmed workpiece, Patent Document 1 discloses a method of using a microscope to measure from its focus position, and a method of measuring from a step profile obtained using a white light interference microscope.

[0005] Japanese Patent Application Laid-Open No. 2021-125592

[0006] However, white light interference microscopes have the problem that they have a narrow field of view and require scanning in the depth direction, which makes measurement time-consuming.

[0007] Furthermore, when measuring the position of the workpiece in the Z direction, which is the normal direction of the surface, for example, the displacement sensor moves while the chuck table is fixed to perform the measurement. Since the chuck table may have a position change in the Z direction due to a rotational component, an error in the rotational component may be included when measuring the position of the workpiece surface in the Z direction, which may result in the inconvenience of not being able to process to the specified trimming depth.

[0008] The present invention has been made in consideration of the above points, and has as its object to provide a dicing apparatus and a trimming method for a dicing apparatus that are capable of performing high-precision trimming processing on a workpiece on which a device is provided.

[0009] The present invention has the following aspects: A cutting unit including a chuck table capable of holding a workpiece on a holding surface and moving in the X direction, a rotary table for rotating the chuck table around the Z axis, a microscope capable of moving in the Y direction and capable of observing the workpiece, a displacement sensor capable of moving in the Y direction and measuring the position of the workpiece in the normal direction, a blade for cutting the workpiece held on the chuck table, and a spindle for rotating the blade around a rotation axis perpendicular to the normal direction, and a control unit for controlling the movement of the chuck table, the rotary table, the microscope, and the displacement sensor based on the measurement results of the microscope and the displacement sensor. and a control unit that controls the above-mentioned, wherein the workpiece has a plurality of devices arranged in areas partitioned by a plurality of first groove portions extending in the X direction and a plurality of second groove portions extending in the Y direction, and the control unit acquires workpiece position information regarding the normal position at a circumferential position centered on the Z axis over the entire circumference of a specific location of a predetermined device of the devices on the workpiece that is located outward in a radial direction centered on the Z axis based on the measurement results of the displacement sensor, and causes the blade to cut a step portion recessed in the Z direction on the outer periphery of the workpiece based on the acquired workpiece position information.

[0010] The present invention also has the following aspects: A trimming method for a dicing device including a chuck table capable of holding a workpiece on a holding surface and moving in the X direction, a rotary table for rotating the chuck table around the Z axis, a cutting unit including a microscope capable of moving in the Y direction and capable of observing the workpiece, a displacement sensor capable of moving in the Y direction and measuring the position of the workpiece in the normal direction, a blade for cutting the workpiece held on the chuck table, and a spindle for rotating the blade around a rotation axis perpendicular to the normal direction, and a control unit for controlling movement of the chuck table, the rotary table, the microscope, and the displacement sensor based on measurement results of the microscope and the displacement sensor, wherein the method comprises the steps of: forming a plurality of first groove portions and a plurality of second groove portions extending in the X direction; and a plurality of second groove portions extending in the Y direction; acquiring work position information regarding the normal position of the work at a circumferential position centered on the Z axis, over the entire circumference, for a specific location of a predetermined device of the devices on the work that is located radially outwardly about the Z axis, based on measurement results of the displacement sensor; and cutting a step recessed in the Z direction into the outer periphery of the work with the blade based on the acquired work position information.

[0011] The present invention can provide a dicing apparatus and a trimming method for the dicing apparatus that are capable of performing high-precision trimming on a workpiece on which a device is provided.

[0012] FIG. 1 is a perspective view of a dicing apparatus according to an embodiment of the present invention. FIG. 2 is a control block diagram of the dicing apparatus. FIG. 3 is a plan view of a workpiece having a device, a first groove portion, and a second groove portion. FIG. 4 is a side view showing the workpiece during trimming. FIG. 5 is a partial cross-sectional view of a trimmed workpiece. FIG. 6 is a diagram showing the procedure for acquiring table position information. FIG. 7 is a partial enlarged view of the periphery of the device. FIG. 8 is a diagram showing the relationship between the position of the holding surface in the θ direction and the cutting height of the blade. FIG. 9 is a diagram showing the relationship between the position of the workpiece surface in the θ direction and the cutting height of the blade in the first trimming operation and the cutting height of the blade in the second trimming operation. FIG. 10 is a diagram showing the procedure for acquiring step position information. FIG. 11 is a plan view of a trimmed workpiece.

[0013] Hereinafter, embodiments of the dicing apparatus and trimming method for the dicing apparatus of the present invention will be described with reference to Figures 1 to 11. Note that the following embodiment shows one aspect of the present invention, does not limit the present invention, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure are different from the actual structure to make each configuration easier to understand.

[0014] 1 is a perspective view showing the essential configuration of a dicing device 10 according to one embodiment of the present invention. The dicing device 10 will be described using a three-dimensional coordinate system of X, Y, and Z. The Z direction is the direction in which a normal line H of the chuck table 42 extends (normal direction). The X direction is a direction perpendicular to the Z direction. The Y direction is a direction perpendicular to the Z direction and the X direction. A rotary table 40, which will be described later, rotates around an axis H extending in the Z direction, and the circumferential direction around the axis H is defined as the θ direction.

[0015] 1, the dicing apparatus 10 has a processing unit 16 that processes the workpiece W, and a control unit CONT that comprehensively controls the operation of each unit in the dicing apparatus 10. The workpiece W is, for example, a silicon wafer. The dicing apparatus 10 may be configured to include a storage unit in which the workpiece W is stored, a placement unit on which the workpiece W is temporarily placed, a cleaning unit that cleans the workpiece W, and the like.

[0016] The processing unit 16 includes an X carriage 32, a chuck table 42, a Y base 44, a Y carriage (first drive unit) 46A, a Y carriage (second drive unit) 46B, Z carriages 50A, 50B, cutting units 51A, 51B, a microscope 60, and a displacement sensor 70.

[0017] The X carriage 32 is movable while being guided in the X direction by X guides 36, 36 which are provided on an X base 34 and extend in the X direction. The X carriage 32 is driven in the X direction indicated by the arrow X-X by a linear motor 38. A rotary table 40 which rotates in the θ direction is fixed to the upper surface of the X carriage 32, and a chuck table 42 which suction-holds the workpiece W is provided on this rotary table 40. Therefore, the chuck table 42 is moved in the X direction by the X carriage 32, and rotated in the θ direction by the rotary table 40.

[0018] Y base 44 is configured in a gate shape so as to straddle X base 34. Y carriages 46A and 46B are provided on the wall surface of Y base 44. Y carriages 46A and 46B are guided by Y guides 48, 48 fixed to the wall surface of Y base 44, and are driven by a drive device made up of a stepping motor and a ball screw (not shown), so that they can move independently of each other in the Y direction indicated by arrow Y-Y.

[0019] Z carriage 50A is provided on Y carriage 46A. Z carriage 50A is guided by a Z guide (not shown) provided on Y carriage 46A, and is driven in the Z direction indicated by arrow ZZ by a drive device (not shown) made up of a stepping motor and a ball screw.

[0020] Z carriage 50B is provided on Y carriage 46B. Z carriage 50B is guided by a Z guide (not shown) provided on Y carriage 46B, and is driven in the Z direction indicated by arrow Z-Z independently of Z carriage 50A by a drive device (not shown) made up of a stepping motor and a ball screw.

[0021] Cutting unit 51A is provided on Z carriage 50A. Cutting unit 51B is provided on Z carriage 50B. Cutting units 51A and 51B each have a spindle 52 and a blade 54. Spindle 52 rotates blade 54 at high speed around rotation axis 53 extending in the Y direction.

[0022] Spindle 52 is fixed facing Z carriages 50A and 50B. Blade 54 is attached to the tip of spindle 52 and positioned opposite it. Spindle 52 and blade 54 can be moved in the Z direction by driving Z carriages 50A and 50B. Spindle 52 and blade 54 can be moved in the Y direction via Z carriages 50A and 50B by driving Y carriages 46A and 46B.

[0023] The microscope 60 is mounted on the Z carriage 50A. The microscope 60 is mounted on the Y carriage 46A via the Z carriage 50A. The microscope 60 can be moved in the Z direction by driving the Z carriage 50A. The microscope 60 can be moved in the Y direction via the Z carriage 50A by driving the Y carriage 46A.

[0024] The microscope 60 is capable of observing the workpiece W held on the chuck table 42. The microscope 60 captures (observes) an image of the surface of the workpiece W held on the chuck table 42. The microscope 60 has a camera 61. The microscope 60 captures an image of the surface of the workpiece W with the camera 61. The positions of the microscope 60 and the camera 61 in the Y direction are the same as the position of the blade 54 provided on the Z carriage 50A in the Y direction.

[0025] The camera 61 includes, for example, a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) imaging element. The captured image information is output to the control unit CONT. The microscope 60 may include an imaging system such as a white light interference microscope in addition to an alignment microscope used for alignment.

[0026] The displacement sensor 70 is mounted on the Z carriage 50B. The displacement sensor 70 is mounted on the Y carriage 46B via the Z carriage 50B. The displacement sensor 70 is movable in the Z direction by driving the Z carriage 50B. The displacement sensor 70 is movable in the Y direction via the Z carriage 50B by driving the Y carriage 46B. The position of the displacement sensor 70 in the Y direction is the same as the position of the blade 54 provided on the Z carriage 50B in the Y direction.

[0027] The displacement sensor 70 includes, for example, an SLD (Superluminescent Diode) light source that emits measurement light, a diffractive optical element, the above-mentioned imaging element, etc. The displacement sensor 70 measures the position of the workpiece W in the Z direction by receiving reflected light of the measurement light irradiated onto the workpiece W. The measured position in the Z direction is output to the control unit CONT.

[0028] The displacement sensor 70 irradiates a measuring beam from a position about 10 mm away from the workpiece W onto an area of ​​several tens of μm in diameter (for example, 40 μm) on the surface of the workpiece W, and measures the shortest distance within the irradiated area. Therefore, it is possible to measure the correct height even if the surface of the workpiece W is uneven. Furthermore, because the measuring beam is irradiated from a position about 10 mm away from the workpiece W, even if protrusions such as bumps are formed on the surface of the workpiece W, it is possible to perform high-precision measurements without interfering with the protrusions.

[0029] A computer is applied as the hardware of the control unit CONT. FIG. 2 is a control block diagram of the dicing apparatus 10. As shown in FIG. 2, the control unit CONT controls the driving of the linear motor 38 to move the X carriage 32 in the X direction. The control unit CONT moves the chuck table 42 in the X direction by moving the X carriage 32 in the X direction. The control unit CONT controls the rotational drive of the turntable 40 in the θ direction. The control unit CONT rotates the turntable 40 in the θ direction to rotate the chuck table 42 in the θ direction.

[0030] The control unit CONT controls the driving of the Z carriage 50A to move the microscope 60, the camera 61, the spindle 52, and the blade 54 in the Z direction. The control unit CONT controls the driving of the Y carriage 46A to move the microscope 60, the camera 61, the spindle 52, and the blade 54 in the Y direction via the Z carriage 50A.

[0031] The control unit CONT controls the driving of Z carriage 50A to move displacement sensor 70, spindle 52, and blade 54 in the Z direction. The control unit CONT controls the driving of Y carriage 46B to move displacement sensor 70, spindle 52, and blade 54 in the Y direction via Z carriage 50B.

[0032] The control unit CONT receives image information captured by the camera 61. The control unit CONT processes the received image information to calculate and obtain position information of the workpiece W (chuck table 42) in the X and Y directions.

[0033] The control unit CONT controls the position of the workpiece W (chuck table 42) in the X direction by controlling the drive of the linear motor 38 based on the acquired position information of the workpiece W (chuck table 42). The control unit CONT controls the position of the workpiece W (chuck table 42) in the θ direction by controlling the drive of the rotary table 40 based on the acquired position information of the workpiece W (chuck table 42).

[0034] The control unit CONT controls the driving of the Y carriage 46A based on the acquired position information of the workpiece W (chuck table 42), thereby controlling the Y direction positions of the microscope 60, camera 61, spindle 52, and blade 54. The control unit CONT controls the Y direction positions of the displacement sensor 70, spindle 52, and blade 54 by controlling the driving of the Y carriage 46B based on the acquired position information of the workpiece W (chuck table 42) and the relative positional relationship in the Y direction between the Y carriage 46A and the Y carriage 46B.

[0035] The control unit CONT can control the Z-directional cutting feed amount of the blade 54 into the workpiece W by controlling the drive of the Z carriages 50A and 50B based on the Z-directional position of the workpiece W measured by the displacement sensor 70.

[0036] The above-described configuration of the processing unit 16 allows the rotary table 40 to be driven based on the acquired position information of the workpiece W, thereby adjusting the position of the workpiece W in the θ direction and performing alignment. The blade 54 is index-fed in the Y direction by driving the Y carriages 46A and 46B, and is cut-fed in the Z direction by driving the Z carriages 50A and 50B, and the chuck table 42 is cut-fed in the X direction and rotated in the θ direction by driving the linear motor 38 and the rotary table 40.

[0037] 3 is a plan view of a workpiece W having a device C, a first groove portion S1, and a second groove portion S2. As shown in FIG. 3, the workpiece W has a plurality of individual chips as devices C, each of which is cut into a grid pattern on the surface Wa by the operation of the processing unit 16 and the rotating blade 54, with first groove portions S1 extending in the X direction and spaced apart in the Y direction, and second groove portions S2 extending in the Y direction and spaced apart in the X direction. A plurality of devices C are arranged in an area defined by the first groove portion S1 and the second groove portion S2. As an example, the device C is a semiconductor chip.

[0038] The workpiece W (device C) is cut into individual pieces by having its outer periphery trimmed and then grinding it from the back surface to the first groove portion S1 and the second groove portion S2.

[0039] The trimming method of the dicing apparatus 10 of this embodiment includes preparing a workpiece W having a plurality of devices C arranged in an area defined by a plurality of first grooves S1 extending in the X direction and a plurality of second grooves S2 extending in the Y direction, acquiring workpiece position information relating to the normal position of the workpiece W at a circumferential position centered on the Z axis for a specific location of a predetermined device C of the workpiece W that is located radially outwardly about the Z axis based on the measurement results of the displacement sensor 70, and cutting a step Wb recessed in the Z direction on the outer periphery of the workpiece W with the blade 54 based on the acquired workpiece position information. This will be described in detail below.

[0040] During trimming, in the processing section 16, the blade 54 mounted on the Y carriage 46A cuts into the workpiece W at a position set based on the X and Y positions of the workpiece W when the displacement sensor 70 measures the Z position of the workpiece W.

[0041] In addition, in the processing section 16, in order to prevent edge chipping, a trimming process is performed in which the R-shaped portion of the outer periphery of the workpiece W is removed in advance by the blade 54. Specifically, as shown in Fig. 4, with the back surface of the workpiece W held by suction on the holding surface 42a of the chuck table 42, the blade 54, which is rotated by the drive of the spindle 52, is lowered from above the workpiece W to a predetermined height that reaches a predetermined finishing depth D, thereby cutting into the workpiece W from the front surface Wa side, and the workpiece W is rotated in the θ direction on the turntable 40 to remove the chamfered portion 5 by the finishing depth D.

[0042] The trimming process may be performed by lowering the blade 54 to a predetermined height that reaches the finishing depth D, moving the blade 54 in the Y direction (radial direction) toward the workpiece W to cut into the workpiece W, and rotating the workpiece W in the θ direction on the turntable 40, thereby removing the chamfered portion 5. Alternatively, the blade 54 may be lowered to a predetermined height that reaches the finishing depth D, moving the blade 54 in the X direction (tangential direction) toward the workpiece W to cut into the workpiece W, and rotating the workpiece W in the θ direction on the turntable 40, thereby removing the chamfered portion 5.

[0043] 5, a step Wb having a trimming width L and recessed downward from the surface Wa is formed on the outer periphery of the workpiece W. By forming the step Wb on the workpiece W, an inner region Wc having a circular shape as viewed in the Z direction is formed inside the step Wb, and the outer diameter R1 (the inner diameter of the step Wb) is smaller than the outer diameter R2 of the workpiece W. In other words, the boundary between the inner region Wc and the step Wb, and the outer peripheral portion Wd of the workpiece W, are circular as viewed in the Z direction.

[0044] In the trimming process of this embodiment, before the trimming process, table position information, which is error information of the rotational component of the chuck table 42 (displacement in the Z direction due to rotation), and workpiece position information, which is error information of the rotational component of the workpiece W held on the chuck table 42 (displacement in the Z direction due to rotation), are acquired. The control unit CONT acquires the cutting amount of the workpiece W at the position in the θ direction based on the acquired table position information and workpiece position information. In the trimming process, while rotating the workpiece W, the control unit CONT moves the blade 54 in the Z direction in accordance with the position of the blade 54 in the θ direction and the acquired cutting amount, thereby forming a step Wb at a finishing depth D.

[0045] [First Embodiment of Trimming] Hereinafter, a first embodiment of trimming, in which the step portion Wb is formed to a finishing depth D by cutting with the blade 54, will be described in detail.

[0046] [Acquisition of Error in Rotational Component of Chuck Table 42] Fig. 6 is a diagram showing a procedure for acquiring table position information. As shown in Fig. 6, the control unit CONT irradiates the holding surface 42a of the chuck table 42 that does not hold the workpiece W with the measuring light 71, and rotates the chuck table 42 in the θ direction by the rotary table 40. The position of the holding surface 42a onto which the measuring light 71 is irradiated is preferably a radial position about the axis H where the step portion Wb is formed when the workpiece W is held.

[0047] The control unit CONT acquires, over the entire circumference, table position information that associates the Z-direction position of the holding surface 42a measured by the displacement sensor 70 with the θ-direction position at which the Z-direction position is measured. That is, the control unit CONT acquires, over the entire circumference, table position information related to the Z-direction position of the holding surface 42a at the θ-direction position, as error information of the rotational component of the chuck table 42, based on the measurement result of the displacement sensor 70.

[0048] 3, the control unit CONT uses a microscope 60 to measure the X-axis coordinates and Y-axis coordinates of specific points F of all of the devices C located radially outward from the axis H and close to the outer circumferential surface of the workpiece W, among the multiple devices C on the aligned workpiece W. An example of the specific points F of the devices C is a pad provided on the devices C.

[0049] 7 is a partial enlarged view of the periphery of the device C. When measuring the X-direction coordinate and the Y-direction coordinate of the specific point F, the control unit CONT identifies the position of the intersection of the first groove portion S1 and the second groove portion S2 near the outer peripheral surface of the workpiece W, as shown in FIG. 7, and measures the specific point F in the device C near the outer peripheral surface of the workpiece W using the intersection as a reference.

[0050] Next, the control unit CONT converts all of the X-direction coordinates and Y-direction coordinates of the measured specific point F into positions in the θ direction and distances (radii) from the axis H, using a predetermined position in the θ direction as a reference. The predetermined position in the θ direction is, for example, the position of the blade 54 that performs the trimming process. That is, the control unit CONT converts the position of the measured specific point F from the XY coordinate system to the rθ coordinate system.

[0051] Once the position of the specific point F in the rθ coordinate system has been determined, the control unit CONT moves the displacement sensor 70 to the position of the blade 54 where trimming will be performed. When the control unit CONT has completed moving the displacement sensor 70, the control unit CONT rotates the workpiece W by driving the rotary table 40, while causing the displacement sensor 70 to irradiate the specific point F of the device C with measurement light 71, and acquires the position of the specific point F in the Z direction. When irradiating the specific point F with the measurement light 71, the control unit CONT moves the displacement sensor 70 in the Y direction in accordance with the distance from the axis H of the specific point F, which corresponds to the position of the workpiece W in the θ direction. This makes it possible to intermittently and easily measure the position of the specific point F in the device C to be measured in the Z direction as the workpiece W rotates.

[0052] The control unit CONT determines that a device C with a large error is invalid based on the position of the measured specific point F in the Z direction, does not include the measurement values ​​measured in the invalid device C in the workpiece position information, and sets a device C (predetermined device) determined to be valid. The control unit CONT intermittently acquires error information of the rotational component of the workpiece W over the entire circumference using the measurement values ​​measured in the device C determined to be valid. In FIG. 3, the specific point F in the device C determined to be valid is illustrated.

[0053] The control unit CONT acquires workpiece position information over the entire circumference that associates the Z-direction position of the specific point F intermittently measured by the displacement sensor 70 with the θ-direction position at which the Z-direction position was measured. That is, the control unit CONT acquires workpiece position information regarding the Z-direction position of the specific point F at the θ-direction position over the entire circumference as error information of the rotational component of the workpiece W based on the measurement results of the displacement sensor 70.

[0054] [Trimming of Step Portion Wb] The control unit CONT sets a finishing depth D (for example, 150 μm) and forms the step portion Wb. The control unit CONT forms the step portion Wb at the depth D using at least one of the table position information and the workpiece position information. The control unit CONT moves the blade 54 in the Z direction based on the Z-direction position (displacement) of at least one of the holding surface 42 a of the chuck table 42 in the θ direction and the specific portion F of the workpiece W, and cuts the workpiece W at a Z-direction position that cancels out the Z-direction displacement of at least one of the holding surface 42 a and the specific portion F, thereby forming the step portion Wb.

[0055] The control unit CONT can perform trimming based on the uncut height or the cut depth.

[0056] [Trimming based on uncut height] Figure 8 shows a graph G1 showing the measured position (height) h in the Z direction of the holding surface 42a of the chuck table 42 at a position in the θ direction, and a graph G2 showing the cutting height h of the blade 54 at a position in the θ direction when trimming the workpiece W to a depth D1 using the blade 54.

[0057] As shown in Figure 8, when the workpiece W is rotated, the control unit CONT follows the displacement in the Z-direction height of the holding surface 42a of the chuck table 42 shown in graph G1 at the θ-direction position obtained from the table position information, and moves the blade 54 to the cutting height shown in graph G2 to cut the workpiece W and form a step portion Wb, thereby offsetting the error in the rotational component of the chuck table 42 and making the uncut height f from the holding surface 42a to the step portion Wb constant.

[0058] 9 is a diagram showing a graph G3 indicating a measured position (height) h in the Z direction at a specific point F of the workpiece W at a position in the θ direction, and a graph G2 indicating the cutting height h of the blade 54 at a position in the θ direction when trimming the workpiece W at a depth D1 with the blade 54. As shown in FIG. 9, when the workpiece W is rotated, the control unit CONT follows the displacement of the height in the Z direction of the specific point F of the workpiece W at the position in the θ direction obtained from the workpiece position information, moves the blade 54 to the cutting height indicated by graph G2, and cuts the workpiece W to form a step Wb. This cancels out the error in the rotation component of the specific point F of the workpiece W and makes the cutting depth g from the specific point F to the step Wb constant, thereby making it possible to make the cutting depth from the surface Wa to the step Wb a constant finishing depth D.

[0059] Since the Z-direction position obtained by measuring specific point F is intermittent in the θ direction, the intermittently obtained Z-direction position is supplemented to create work position information, and the blade 54 is moved to the cutting height obtained using the created work position information to perform trimming processing.

[0060] In addition to the uncut height standard or the cutting depth standard, it is also possible to offset both the error in the rotational component of the chuck table 42 and the error in the rotational component of the workpiece W by using both the table position information and the workpiece position information.

[0061] Specifically, the control unit CONT calculates the mutual difference between the error in the rotational component of the chuck table 42 at the position in the θ direction and the error in the rotational component of the workpiece W over the entire circumference. Then, the control unit CONT moves the blade 54 by a descending length that follows the obtained mutual difference in the errors at the position in the θ direction, and cuts the workpiece W to form a step Wb. This makes it possible to cancel out both the error in the rotational component of the chuck table 42 and the error in the rotational component of the workpiece W.

[0062] As described above, in the dicing device 10 of this embodiment, table position information regarding the Z-direction position of the holding surface 42a at the θ-direction position and work position information regarding the Z-direction position of a specific location F of the work W at the θ-direction position are obtained based on the measurement results of the displacement sensor 70, and the work W is cut based on the obtained table position information and work position information to form the step portion Wb, thereby enabling high-precision trimming processing in which errors in the rotational components of the chuck table 42 and the work W are corrected.

[0063] Furthermore, the dicing apparatus 10 of this embodiment uses work position information obtained by measuring a specific location F of the device C on the work W. Therefore, even if foreign matter such as residue from device formation or metal residue is present on the surface of the work W, high-precision trimming processing is possible without being affected by the presence of the foreign matter, and the number of data items can be reduced compared to when the entire surface Wa of the work W is measured.

[0064] [Second embodiment of trimming] Next, a second embodiment of trimming will be described, in which the step Wb is formed to the finishing depth D by cutting with the blade 54. In the first embodiment of trimming described above, the procedure for forming the step Wb to the finishing depth D by cutting with the blade 54 once was described. However, in the second embodiment, a procedure for forming the cutting height, radial position, and eccentricity of the step Wb with high precision by cutting with the blade 54 twice will be described.

[0065] Specifically, in the second embodiment, the control unit CONT, based on the acquired workpiece position information described above, forms a step Wb during the first cutting by reducing the cutting amount below the amount required for finishing, and then acquires step position information, which is error information in the Z direction of the step Wb, and radial position information. During the second cutting, the control unit CONT corrects the error using the step position information and radial position information based on the acquired step position information, and performs re-cutting. Each step will be described below.

[0066] [First Trimming of Step Portion Wb] In the second embodiment, the control unit CONT, based on the workpiece position information, forms the step portion Wb in the first trimming to a depth D1 (e.g., 140 μm) shallower than the finishing depth D (e.g., 150 μm). The difference between the finishing depth D and the depth D1 is preferably set to a value greater than the amount of error expected based on, for example, the workpiece position information.

[0067] The first trimming of the stepped portion Wb can be performed by selecting the above-mentioned uncut height standard, cutting depth standard, and standard using both the table position information and the workpiece position information.

[0068] [Regarding Cutting Height] Here, two trimming processes based on the cutting depth will be explained.

[0069] [Acquisition of step position information] Figure 10 shows a graph G3 showing the relationship between the position in the θ direction and the measured position (height) h in the Z direction at a specific location F of the workpiece W, and a graph G21 showing the relationship between the cutting height h of the blade 54 at the position in the θ direction when trimming the workpiece W with the blade 54 at a cutting depth (cutting amount) g in the first trimming process.

[0070] 10, when forming the step portion Wb in the first trimming process, the control unit CONT acquires the measured position h=f(θ) in the Z direction of the specific point F of the workpiece W at the position in the θ direction over the entire circumference as workpiece position information, as described above. Thereafter, the control unit CONT cuts the workpiece W at a cutting height of h=f(θ)-g to form the step portion Wb.

[0071] After the step Wb is formed in the first trimming process, the control unit CONT acquires step position information, which is error information of the rotational component of the step Wb.

[0072] Fig. 11 is a diagram showing a procedure for acquiring step position information. The device C is not shown in Fig. 11. As shown in Fig. 11, the control unit CONT irradiates the step Wb of the workpiece W held on the chuck table 42 with the measurement light 71, and rotates the chuck table 42 and the workpiece W in the θ direction by the rotary table 40.

[0073] The control unit CONT acquires step position information over the entire circumference that associates the Z-direction position of the step Wb measured by the displacement sensor 70 with the θ-direction position at which the Z-direction position was measured. That is, the control unit CONT acquires step position information relating to the Z-direction position of the step Wb at the θ-direction position based on the measurement results of the displacement sensor 70, and acquires h=g(θ) over the entire circumference as error information of the rotational component of the step Wb.

[0074] Here, if the machining error in the Z direction at the position in the θ direction during the first trimming is e(θ), e(θ) can be calculated by the following formula (1): e(θ)=g(θ)-f(θ)+g (1)

[0075] The cutting height h during the second trimming process shown in graph G21 is expressed by the following formula (2) using the second cutting depth g2 and the processing error e(θ) obtained by formula (1): h=f(θ)-g-g2-e(θ) (2)

[0076] Then, the following equation (3) is obtained from equations (1) and (2): h = 2 × f(θ) - g(θ) - 2 × g - g2 (3)

[0077] The control unit CONT performs the second trimming process to form the step Wb by cutting to the cutting height calculated by the formula (3), thereby eliminating the processing error during the first trimming process.

[0078] The machining error e(θ) is not caused by measurement, but is caused by deflection of the blade 54, deflection of the chuck table 42, deformation of the workpiece W, and the like that occur only during machining due to the machining load. Therefore, the more equal the loads during the first and second trimming processes, the more highly accurate the depth machining becomes. Furthermore, in trimming based on the uncut height, as in trimming based on the above-mentioned cutting depth, highly accurate depth machining is possible by performing two trimming processes.

[0079] [Regarding radial position] Before causing the blade 54 to re-cut the step portion Wb, the control unit CONT acquires the amount and direction of eccentricity between the first center C1 of the outer diameter R2 of the workpiece W and the second center C2 of the inner diameter R1 of the step portion Wb, as shown in Figure 12, in relation to the step portion Wb formed in the first trimming process.

[0080] Specifically, the control unit CONT controls the positions of the X carriage 32 and the Y carriage 46B to cause the measurement light 71 of the displacement sensor 70 to scan along a plane parallel to the X direction and the Y direction (XY plane). More specifically, the control unit CONT causes the measurement light 71 to scan in the radial direction centered on the first center C1 of the outer diameter of the workpiece W, and to cross the step Wb between the inner region Wc and the outside of the workpiece W.

[0081] The displacement sensor 70 continuously outputs to the control unit CONT the Z-direction positions of the surface Wa of the workpiece W, the step Wb, and the outside of the workpiece W (chuck table 42) measured when the measurement light 71 crosses the step Wb, in correspondence with the position in the XY plane where each Z-direction position was measured.

[0082] Based on the measured Z-direction position value output by the displacement sensor 70 and the position in the XY plane where each Z-direction position is measured, the control unit CONT calculates and obtains the X-direction position and Y-direction position of the first edge portion E1 where the Z-direction measurement value changes at the boundary between the surface Wa of the workpiece W and the step portion Wb when the measurement light 71 crosses the step portion Wb, as shown in Figure 4, and the X-direction position and Y-direction position of the second edge portion E2 located on the outer portion Wd of the workpiece W.

[0083] Furthermore, if measurement results show that there is a protrusion bulging upward at the step Wb between the first edge portion E1 and the second edge portion E2, uneven wear of the blade 54 can be detected, for example.

[0084] The control unit CONT performs the position measurement of the first edge portion E1 and the second edge portion E2 at three or more different positions in the circumferential direction around the first center C1, as shown in FIG. 12 . In this embodiment, the position measurement is performed at three different positions in the circumferential direction: θ1, θ2, and θ3. The first edge portion E1 at positions θ1, θ2, and θ3 is referred to as the first edge portion E11, the first edge portion E12, and the first edge portion E13, respectively. The second edge portion E2 at positions θ1, θ2, and θ3 is referred to as the second edge portion E21, the second edge portion E22, and the second edge portion E23, respectively.

[0085] The control unit CONT can calculate and acquire the outer diameter of the workpiece W and the position of the first center C1 based on the coordinates of the second edge portion E21, the second edge portion E22, and the second edge portion E23 on the XY plane. The control unit CONT can calculate and acquire the outer diameter R1 (inner diameter of the step portion Wb) of the inner region Wc and the position of the second center C2 based on the coordinates of the first edge portion E11, the first edge portion E12, and the first edge portion E13 on the XY plane. The control unit CONT can acquire the amount and direction of eccentricity of the inner region Wc relative to the workpiece W from the acquired positions of the first center C1 and the second center C2. The control unit CONT can acquire the amount of positional deviation of the blade 54 based on the amount of eccentricity of the inner region Wc relative to the workpiece W.

[0086] Then, in the second trimming process, the control unit CONT adjusts the positions of the X carriage 32 and the Y carriage 46A to correct the amount and direction of eccentricity of the inner region Wc, and sets the trimming width L so that the outer diameter of the inner region Wc becomes the specified outer diameter, and re-cuts the workpiece W, thereby forming an inner region Wc with the specified outer diameter R1 (inner diameter of the step portion Wb) with the eccentricity corrected.

[0087] As described above, in the dicing device 10 of this embodiment, in addition to achieving the same functions and effects as in the first embodiment, based on the acquired work position information, the blade 54 is caused to cut a step Wb recessed in the Z direction at a depth g shallower than the predetermined depth D on the outer periphery of the work W, and then step position information regarding the Z direction position of the step Wb in the θ direction is acquired based on the measurement results of the displacement sensor 70, and the blade 54 is caused to re-cut the step Wb with a cutting amount g2 that is the difference between the acquired step position information and the predetermined depth D, thereby enabling even more precise trimming processing.

[0088] Furthermore, in the dicing device 10 of this embodiment, after the first trimming process forms a step Wb in the inner region Wc with an inner diameter larger than the specified diameter dimension, the blade 54 is used in the second trimming process to correct the amount and direction of eccentricity between the first center C1 of the outer diameter R2 of the workpiece W and the second center C2 of the inner diameter R1 of the step Wb, and the workpiece W is re-cut, thereby forming an inner region Wc with the specified diameter dimension and eccentricity corrected with high precision.

[0089] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0090] For example, in the above embodiment, the step portion Wb is formed by one or two trimming processes, but the present invention is not limited to this configuration and may be formed by three or more trimming processes.

[0091] In addition, in the above embodiment, a configuration in which the specific location F on device C is a pad is exemplified, but this configuration is not limited to this, and other locations may be used as long as they are easy to identify on device C and can be measured by displacement sensor 70.

[0092] In addition, in the above embodiment, an example was given of a configuration in which the step portion Wb is formed based on table position information and work position information, but this configuration is not limited to this, and the step portion Wb may be formed based on work position information without using table position information.

[0093] 10...Dicing device, 40...Rotary table, 42...Chuck table, 46A...Y carriage (first drive unit), 46B...Y carriage (second drive unit), 51A, 51B...Cutting unit, 52...Spindle, 53...Rotary axis, 54...Blade, 60...Microscope, 70...Displacement sensor, 71...Measuring light, C...Device, CONT...Control unit, H...Axis, S1...First groove portion, S2...Second groove portion, W...Work, Wb...Step portion, Wc...Inner region, Wd...Outer portion

Claims

1. A cutting unit including: a chuck table capable of holding a workpiece on a holding surface and moving in the X direction; a rotary table for rotating the chuck table around the Z axis; a microscope capable of moving in the Y direction and capable of observing the workpiece; a displacement sensor capable of moving in the Y direction and measuring the position of the workpiece in the normal direction; a blade for cutting the workpiece held on the chuck table; and a spindle for rotating the blade around a rotation axis perpendicular to the normal direction; and a control unit for controlling the movement of the chuck table, the rotary table, the microscope, and the displacement sensor based on measurement results of the microscope and the displacement sensor, wherein the workpiece has a plurality of devices arranged in an area defined by a plurality of first groove portions extending in the X direction and a plurality of second groove portions extending in the Y direction, and the control unit acquires workpiece position information relating to the normal position at a circumferential position around the Z axis for a specific location of a predetermined device of the devices on the workpiece located outward in a radial direction around the Z axis, over the entire circumference based on the measurement results of the displacement sensor, A dicing device that causes the blade to cut a stepped portion recessed in the Z direction on the outer periphery of the workpiece based on the acquired workpiece position information.

2. The dicing device of claim 1, wherein the control unit acquires the cutting amount at the circumferential position based on the acquired workpiece position information, and while rotating the workpiece, moves the blade in the normal direction according to the circumferential position of the blade and the acquired cutting amount to cut the step portion.

3. The dicing device of claim 2, wherein the control unit causes the blade to cut the step to a depth shallower than a predetermined depth based on the acquired workpiece position information, and then acquires step position information relating to the normal position of the step at the circumferential position over the entire circumference based on the measurement results of the displacement sensor, and causes the blade to re-cut the step by an amount of cutting that is the difference between the step position information and the predetermined depth.

4. The dicing device according to claim 2, wherein the control unit acquires the cutting amount at the circumferential position based on table position information relating to the position of the holding surface in the normal direction at the circumferential position and the workpiece position information.

5. The dicing device of claim 3, wherein the control unit causes the blade to cut the step portion to a depth shallower than the predetermined depth based on table position information relating to the normal position of the holding surface at the circumferential position and the work position information.

6. The dicing device described in claim 5, wherein, before causing the blade to re-cut the step portion, the control unit obtains the amount and direction of eccentricity between a first center of the outer diameter of the workpiece and a second center of the inner diameter of the step portion based on the measurement results of the displacement sensor, and causes the blade to re-cut the step portion at a position where the second center has been corrected based on the amount and direction of eccentricity.

7. The dicing device according to claim 6, wherein the control unit causes the blade to cut the step recessed in the Z direction at a depth shallower than the predetermined depth on the outer periphery of the workpiece, and causes the step to be formed with an inner diameter larger than a predetermined diameter dimension.

8. A dicing device according to any one of claims 1, 4, 5, 6 and 7, wherein the control unit converts the X-direction and Y-direction coordinates of the specific location into the circumferential position and the distance from the Z-axis, and moves the displacement sensor in the Y direction according to the circumferential position of the specific location to measure the position in the normal direction.

9. The dicing apparatus according to any one of claims 1, 4, 5, 6 and 7, wherein the specific location is a pad provided on the device.

10. A dicing device as described in any one of claims 1, 4, 5, 6 and 7, wherein the control unit sets a specific device included in the work position information according to the results of the displacement sensor measuring the normal direction positions of all of the devices.

11. A dicing device according to any one of claims 5 to 7, wherein the relationship h = 2 × f(θ) - g(θ) - 2 × g - g2 is satisfied, where f(θ) is the workpiece position information, g(θ) is the step position information, g is a cutting depth shallower than the predetermined depth at the circumferential position, g2 is the difference in cutting amount between the step position information and the predetermined depth, and h is the cutting height of the blade in the normal direction when re-cutting.

12. A trimming method for a dicing device equipped with a chuck table capable of holding a workpiece on a holding surface and moving in the X direction, a rotary table for rotating the chuck table around the Z axis, a cutting unit including a microscope capable of moving in the Y direction and capable of observing the workpiece, a displacement sensor capable of moving in the Y direction and measuring the position of the workpiece in the normal direction, a blade for cutting the workpiece held on the chuck table, and a spindle for rotating the blade around a rotation axis perpendicular to the normal direction, and a control unit for controlling movement of the chuck table, the rotary table, the microscope, and the displacement sensor based on measurement results of the microscope and the displacement sensor, comprising: preparing the workpiece having a plurality of devices arranged in areas partitioned by a plurality of first groove portions extending in the X direction and a plurality of second groove portions extending in the Y direction; A trimming method for a dicing device, comprising: acquiring work position information regarding the normal position of the work at a circumferential position centered on the Z axis, over the entire circumference, based on the measurement results of the displacement sensor, for a specific location of a predetermined device of the devices on the work that is located radially outwardly about the Z axis; and causing the blade to cut a step recessed in the Z direction on the outer periphery of the work based on the acquired work position information.

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