Method for inspecting dicing grooves and dicing apparatus

Abstract

The present invention provides a method for inspecting dicing grooves and a dicing apparatus that enable accurate and easy kerf checking when performing step cuts. [Solution] The method for inspecting a dicing groove involves the steps of: forming a first dicing groove on the surface of a workpiece using a first blade attached to a first cutting section; forming a second dicing groove within the first dicing groove along the first dicing groove using a second blade attached to a second cutting section separate from the first cutting section; and detecting at least one of the workpiece surface, the first dicing groove, and the second dicing groove using an observation section, wherein the timing for photographing at least one of the grooves with the observation section is adjusted according to the rotation period of the second blade.

Description

Technical Field

[0001] The present invention relates to a method for inspecting dicing grooves and a dicing apparatus, and more particularly to a method for inspecting dicing grooves for dividing a workpiece such as a wafer on which a semiconductor device or an electronic component is formed into individual chips.

Background Art

[0002] A dicing apparatus for dividing a workpiece such as a wafer on which a device pattern of a semiconductor device or an electronic component is formed into individual chips includes a blade that is rotated at high speed by a spindle, a worktable that adsorbs and holds the workpiece, and an XYZθ drive unit that changes the relative position between the worktable and the blade. In this dicing apparatus, dicing processing (cutting processing) is performed by cutting the workpiece with the blade while relatively moving the blade and the workpiece by each drive unit.

[0003] When performing dicing processing, in order to confirm the quality of the cutting line and the positional accuracy of the dicing groove, measurement (kerf check) of the processing area is performed (see, for example, Patent Documents 1 and 2).

[0004] By the way, when a workpiece composed of a silicon layer and a device layer (metal film) formed on the surface of the silicon layer is divided by a single cutting process (single cut), the processing quality on the back side of the workpiece may deteriorate due to the influence of the device layer or the like. Therefore, in dicing processing, in order to improve the processing quality, step cutting is performed step by step using a surface blade for removing the metal on the surface of the workpiece and a silicon blade for cutting the silicon layer inside the workpiece. In step cutting, since the surface blade and the silicon blade cut into the same position on the workpiece surface, it is impossible to observe the dicing groove formed by the silicon blade described later with a microscope from above the workpiece surface.

[0005] Figure 10 is a cross-sectional view showing an example of step cutting. As shown in Figure 10, the workpiece consists of a device layer W1 formed on the surface side and a silicon layer W2, with dicing tape T attached to the back side of the silicon layer W2. In the figure, the symbol g1 is a groove formed when the device layer W1 is removed with a surface blade, and the symbol g2 is a groove for cutting the silicon layer W2 with a silicon blade. As shown in Figure 10, the edge portion e2 of groove g2 is inside groove g1 and therefore cannot be observed with a microscope. Also, because groove g1 is inclined, it was difficult to accurately measure the position with a measuring instrument.

[0006] Therefore, when performing step cuts, it is advisable to first use a silicon blade to perform a small check cut on the workpiece surface to check the blade's position and condition. However, in this case, the check cut may damage the silicon blade, potentially degrading the processing quality. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2015-085397 [Patent Document 2] Japanese Patent Publication No. 2015-099026 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] To solve the problems described above, one could consider observing the surface in three dimensions using a laser microscope or interference microscope instead of an optical microscope. However, even with laser microscopes or interference microscopes, it is generally difficult to stably measure nearly vertical surfaces such as groove walls from an optical standpoint.

[0009] Furthermore, when measuring grooves, there are problems inherent to the dicing equipment. Specifically, blade dicing equipment has a spindle, and vibrations are generated depending on the rotation speed of the spindle and blade. These vibrations can be a disturbance to precise measurements on the dicing equipment and may affect the measurement results.

[0010] To suppress the effects of this vibration, one could consider changing the rotation speed to a level that minimizes its impact on groove measurement accuracy, or stopping the rotation altogether. However, in this case, time would be required to vary the rotation speed during groove measurement, which would affect the productivity of the device.

[0011] This invention has been made in view of these circumstances, and aims to provide a method for inspecting dicing grooves and a dicing apparatus that can perform kerf checks accurately and easily when performing step cuts. [Means for solving the problem]

[0012] To solve the above problems, a method for inspecting a dicing groove according to a first aspect of the present invention comprises the steps of: forming a first dicing groove on the surface of a workpiece using a first blade attached to a first cutting section; forming a second dicing groove within the first dicing groove along the first dicing groove using a second blade attached to a second cutting section separate from the first cutting section; and detecting the edge portion between the first dicing groove and the second dicing groove using an observation section attached to the second cutting section, wherein the timing of photographing the edge portion with the observation section is adjusted according to the rotation speed of the second blade.

[0013] In the second aspect of the present invention, the method for inspecting dicing grooves, in the first aspect, adjusts the timing of imaging by the observation unit in synchronization with the rotation period of the second blade.

[0014] In the third aspect of the present invention, the method for inspecting dicing grooves is, in the first or second aspect, such that the timing interval for taking images with the observation unit is an integer multiple of the rotation speed of the second blade.

[0015] In the fourth aspect of the present invention, the method for inspecting a dicing groove, in the first aspect, synchronizes the timing at which the observation unit reaches the shooting execution position with the rotation period of the second blade.

[0016] In the fifth aspect of the present invention, the method for inspecting dicing grooves is such that, in the first or fourth aspect, the timing interval at which the observation unit reaches the shooting execution position is an integer multiple of the rotation speed of the second blade.

[0017] A dicing apparatus according to a sixth aspect of the present invention comprises a first cutting unit equipped with a first blade for forming a first dicing groove on the surface of a workpiece; a second cutting unit equipped with a second blade for forming a second dicing groove within the first dicing groove along the first dicing groove; an observation unit attached to the second cutting unit for detecting the edge portion between the first dicing groove and the second dicing groove; and a control unit for adjusting the timing of photographing the edge portion with the observation unit according to the rotation speed of the second blade. [Effects of the Invention]

[0018] According to the present invention, calf checks can be performed accurately and easily when performing step cuts. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a perspective view showing a dicing apparatus according to an embodiment. [Figure 2] Figure 2 is a perspective view showing an example of a step cut. [Figure 3] Figure 3 is a schematic diagram of the observation section of the dicing apparatus. [Figure 4] Figure 4 is a cross-sectional view showing an overview of the observation section. [Figure 5]FIG. 5 is a block diagram showing a control system of a dicing apparatus according to an embodiment. [Figure 6] FIG. 6 is a diagram showing the relationship between the rotational frequency of the blade and the frame rate. [Figure 7] FIG. 7 is a diagram showing the relationship between the rotational frequency of the blade and the scanning position (imaging execution position). [Figure 8] FIG. 8 is a graph showing the relationship between the scan speed, the frame rate, and the rotational speed of the second spindle. [Figure 9] FIG. 9 is a flowchart showing an inspection method for a dicing groove according to an embodiment and a modification example 1. [Figure 10] FIG. 10 is a cross-sectional view showing an example of a step cut.

BEST MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, an inspection method for a dicing groove and a dicing apparatus according to an embodiment will be described with reference to the accompanying drawings.

[0021] (Embodiment) FIG. 1 is a perspective view showing a dicing apparatus according to an embodiment of the present invention. In FIG. 1, the X direction, the Y direction, and the Z direction are shown. The X direction and the Y direction intersect each other. For example, the X direction and the Y direction are orthogonal to each other. The Z direction intersects the X direction and the Y direction. For example, the Z direction is perpendicular to the X direction and the Y direction. Hereinafter, the lengths in the X direction and the Y direction may be referred to as thickness or width. The length in the Z direction may be referred to as thickness, depth, and height. Also, in the Z direction, the direction toward the tip side of the arrow in the Z direction may be referred to as the upward direction, the upper side, or the top, and the direction opposite to the upward direction may be referred to as the downward direction, the lower side, or the bottom.

[0022] As shown in Figure 1, the dicing apparatus 10 according to this embodiment has a cutting section 12 (first cutting section 12-1 and second cutting section 12-2) for dicing a workpiece W, and a table CT. In the following description, the sub-numbers will be omitted for components common to the two cutting sections 12-1 and 12-2.

[0023] The table CT has a holding surface parallel to the XY plane. The table CT holds the workpiece W by suction using a vacuum source (vacuum generator, e.g., ejector, pump, etc.) not shown. The workpiece W is attached to a frame (not shown) via a dicing tape (not shown) having an adhesive layer formed on its surface, and is held by the table CT by suction. The frame to which the dicing tape is attached is held by a frame holding means (not shown) provided on the table CT. A transport configuration without a frame is also possible.

[0024] The CT table is mounted on a θ table (not shown), which is rotatable in the θ direction (around a rotation axis centered on the Z axis) by a rotation drive unit including a motor, etc. The θ table is placed on an X table (not shown). The X table is movable in the X direction by an X drive unit including, for example, a motor and a ball screw, etc.

[0025] The first cutting section 12-1 and the second cutting section 12-2 are mounted on the Z1 table and the Z2 table, respectively. The Z1 table and the Z2 table are movable in the Z1 and Z2 directions, respectively, by a Z drive unit including a motor and a ball screw. The Z1 table and the Z2 table are mounted on the Y1 table and the Y2 table, respectively. The Y1 table and the Y2 table are movable in the Y1 and Y2 directions, respectively, by a Y drive unit including a motor and a ball screw, respectively.

[0026] In this embodiment, the X drive unit, Y drive unit, and Z drive unit are configured to include a motor and a ball screw, but the present invention is not limited thereto. For example, the X drive unit, Y drive unit, and Z drive unit can be configured to include a mechanism for reciprocating linear motion, such as a rack and pinion mechanism.

[0027] As shown in Figure 1, the first cutting section 12-1 includes a first spindle 14-1 and a first blade 16-1. The second cutting section 12-2 includes a second spindle 14-2 and a second blade 16-2.

[0028] The first blade 16-1 and the second blade 16-2 are, for example, disc-shaped cutting blades. The first blade 16-1 is a blade for removing the surface layer of the workpiece W (hereinafter sometimes referred to as the upper layer), for example, the device layer, for example, a surface blade. The second blade 16-2 is a blade for cutting (dividing) the layer located below the upper layer of the workpiece W (hereinafter sometimes referred to as the lower layer), for example, the silicon layer, for example, a silicon blade. In the example shown in Figure 1, the thickness of the first blade 16-1 is greater than the thickness of the second blade 16-2. As the first blade 16-1 and the second blade 16-2, for example, electroplated blades in which diamond abrasive grains or CBN (Cubic Boron Nitride) abrasive grains are electroplated with nickel, or resin blades bonded with resin can be used. The first blade 16-1 and the second blade 16-2 are interchangeable depending on the type and size of the workpiece W to be processed and the processing content.

[0029] The first blade 16-1 and the second blade 16-2 are mounted on the tips of the first spindle 14-1 and the second spindle 14-2, respectively. The first spindle 14-1 and the second spindle 14-2 each contain high-frequency motors for high-speed rotation of the first blade 16-1 and the second blade 16-2.

[0030] With the configuration described above, the first blade 16-1 and the second blade 16-2 are indexed and fed in the Y1 and Y2 directions in the Y direction, respectively, and cut and fed in the Z1 and Z2 directions in the Z direction. The table CT is rotated in the θ direction and cut and fed in the X direction.

[0031] Figure 2 is a perspective view showing an example of a step cut. The dicing device 10 can perform step cuts along the dicing direction (X direction). For example, as shown in Figure 2, the dicing device 10 uses the first blade 16-1 to cut deeper than the device layer of the surface Wa of the workpiece W to form a groove (hereinafter referred to as the first dicing groove) G1 along the X direction. Then, the dicing device 10 uses the second blade 16-2 to form a groove (hereinafter referred to as the second dicing groove) G2 along the X direction.

[0032] Figure 3 is a schematic diagram of the observation section of the dicing apparatus, and Figure 4 is a cross-sectional view showing an overview of the observation section. Note that in Figure 3, the second blade 16-2, etc., are omitted for the sake of simplicity.

[0033] The observation unit MS is attached to the side of the second cutting unit 12-2 and is movable integrally with the second cutting unit 12-2. The observation unit MS takes (observes) an image of the surface of the workpiece W held by adsorption to the table CT. The observation unit MS includes, for example, a white light interference microscope, an alignment microscope used for alignment, or a shape detection microscope used for shape detection.

[0034] As shown in Figure 3, the observation unit MS includes a light source unit 200, an interference lens 202, a microscope 204, and a camera 206.

[0035] The light source unit 200 emits parallel beam white light (low coherence light with low coherence) under the control of the control device 100. This light source unit 200 includes a light source capable of emitting white light, such as a light-emitting diode, semiconductor laser, halogen lamp, and high-intensity discharge lamp, and a collector lens that converts the white light emitted from this light source into a parallel beam.

[0036] The interference lens 202 includes a beam splitter 220, a reference plane 222, and an objective lens 224. While Figure 4 illustrates an example of a Mirau-type interference optical system, it is not limited to this. For example, other interference optical systems such as Michelson-type or Linik-type systems can be used in the observation unit MS (e.g., interference lens 202).

[0037] As shown in Figure 4, a beam splitter 220 and an objective lens 224 are arranged in order along the Z-direction upward from the surface Wa of the workpiece, which is the surface to be measured. A reference surface 222 is positioned opposite the beam splitter 220 (between the beam splitter 220 and the objective lens 224).

[0038] The objective lens 224 has a light-gathering function, and focuses the white light L1 incident from the light source unit 200 onto the surface Wa to be measured through the beam splitter 220.

[0039] The beam splitter 220 splits a portion of the white light L1 incident from the objective lens 224 as reference light L2b, transmits the remaining measurement light L2a to the surface to be measured Wa, and reflects the reference light L2b toward the reference surface 222. The measurement light L1a that has passed through the beam splitter 220 is irradiated onto the surface to be measured Wa, and then reflected by the surface to be measured Wa and returns to the beam splitter 220.

[0040] The reference surface 222, for example, uses a reflective mirror to reflect the reference light L2b incident from the beam splitter 220 back towards the beam splitter 220. The position of this reference surface 222 can be manually adjusted in the X direction by a position adjustment mechanism (e.g., a ball screw mechanism, actuator, etc.). This allows adjustment of the optical path length (reference optical path length) of the reference light L2b between the beam splitter 220 and the reference surface 222. This reference optical path length is adjusted to match (or nearly match) the optical path length (measurement optical path length) of the measurement light L1 between the beam splitter 220 and the surface Wa under measurement.

[0041] The measurement light L2a returning from the surface to be measured Wa and the reference light L2b returning from the reference surface 222 are combined by the beam splitter 220 and reach the objective lens 224 as combined light L3.

[0042] The combined light L3 passes through the objective lens 224 and is then imaged onto the imaging plane of the camera 206 by the microscope 204. Specifically, the combined light L3 images a point on the focal plane of the objective lens 224 as an image point on the imaging plane of the camera 206.

[0043] Camera 206 is equipped with a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) type imaging sensor. Camera 206 captures the combined wave light L3 imaged on the imaging surface, processes the resulting combined wave light L3 signal, and outputs the captured image.

[0044] The control board 106 outputs a trigger to the camera 206 to control the timing of shooting, and the camera 206 adjusts the timing of shooting (frame rate) according to the timing of the trigger from the control board 106. Here, the control device 100 and the control board 106 are examples of the control unit of the present invention.

[0045] Figure 5 is a block diagram showing the control system of a dicing apparatus according to an embodiment. As shown in Figure 5, the control system of the dicing apparatus 10 includes a control device 100, an input unit 102, a display unit 104, a first cutting unit 12-1, a second cutting unit 12-2, a first drive unit 50-1, a second drive unit 50-2, a table drive unit 54, and a table CT.

[0046] The control device 100 includes a CPU (Central Processing Unit) and ROM (Read Only Memory). The dicing device has RAM (Random Access Memory) and a storage device (for example, an HDD (Hard Disk Drive) or SSD (Solid State Drive)). The control device 100 controls each part of the dicing device 10. The control device 100 is, for example, a personal computer or a microcomputer.

[0047] The input unit 102 includes an operation unit (for example, a keyboard or a pointing device) for receiving user input.

[0048] The display unit 104 displays a GUI (Graphical User Interface) for operating the dicing device 10, etc. The display unit 104 includes, for example, a liquid crystal display.

[0049] The first drive unit 50-1 and the second drive unit 50-2 include a power source (for example, a linear motor or a motor drive mechanism) for moving the first cutting unit 12-1 and the second cutting unit 12-2 along the YZ direction, respectively. As the mechanism for moving the first drive unit 50-1 and the second drive unit 50-2, a mechanism capable of reciprocating linear motion, such as a ball screw or a rack and pinion mechanism, can be used.

[0050] The observation unit MS is movable integrally with the second cutting unit 12-2 and is movable in the scanning direction, Z, by the second drive unit 50-2. Alternatively, the observation unit MS may be movable independently of the second cutting unit 12-2.

[0051] The table drive unit 54 includes an X drive unit and a rotation drive unit for moving the table CT.

[0052] In this embodiment, the first cutting section 12-1 and the second cutting section 12-2 are moved in the YZ direction, and the table CT is moved in the Xθ direction. However, the present invention is not limited to this. For example, the table CT may be movable in the YZ direction, and any configuration that allows the first cutting section 12-1 and the second cutting section 12-2 and the table CT to move relative to each other in the XYZθ directions is acceptable.

[0053] The observation unit MS acquires information regarding the three-dimensional shape of the first dicing groove G1 and the second dicing groove G2 by intermittently taking images at a constant frame rate while moving towards or away from the workpiece W.

[0054] When the above operation is performed, the image captured by the observation unit MS is affected by the rotation of the second spindle 14-2. For this reason, in this embodiment, the observation unit MS captures images in a synchronized state, that is, the timing of the camera 206 capture, for example, the frame rate when the camera 206 captures images, is matched to the rotation frequency of the second spindle 14-2. The control board 106 inputs a trigger to the camera 206 to execute the capture based on the rotation frequency of the second spindle 14-2 (for example, the rotation frequency obtained from the number of rotations per unit time detected by the encoder).

[0055] Figure 6 shows the relationship between vibrations caused by blade rotation and the timing of image capture. The horizontal axis in Figure 6 represents time T, and the vertical axis represents the amplitude due to vibration. Curve C1 in Figure 6 shows the change over time of vibrations caused by the rotation of the second spindle 14-2 in the second cutting section 12-2, and the amplitude changes periodically according to the rotation frequency of the second spindle 14-2.

[0056] In the example shown in Figure 6, the timing intervals for the camera 206 to perform image capture (T(i)-T(i-1), T(i+1)-T(i)) coincide with the rotation period of the second spindle 14-2. That is, image capture by the camera 206 is performed with each rotation period of the second spindle 14-2.

[0057] If the rotational speed of the second spindle 14-2 is S revolutions per minute (rpm) and the frame rate of the camera 206 is F frames per second (fps), then the following equation (1) is obtained. The rotational speed of the second spindle 14-2 is assumed to be known.

[0058] S = F / 60 ... (1) As shown in Figure 6, by matching the frame rate F of camera 206 to the rotation speed S of the second spindle 14-2, it is possible to acquire images in which the influence of positional changes of camera 206 due to vibrations caused by the rotation of the second spindle 14-2 is suppressed. This makes it possible to stably acquire information regarding the three-dimensional shapes of the first dicing groove G1 and the second dicing groove G2.

[0059] In the example shown in Figure 6, the timing interval for the camera 206 to perform shooting (T(i)-T(i-1), T(i+1)-T(i)) is matched with the period of the rotational speed F of the second spindle 14-2, but the present invention is not limited to this. For example, the timing interval for the camera 206 to perform shooting (T(i)-T(i-1), T(i+1)-T(i)) may be an integer multiple of the period of the rotational speed F of the second spindle 14-2. In this case, the relationship between the rotational speed S (rpm) of the second spindle 14-2 and the frame rate F (fps) of the camera 206 is expressed by the following equation (2). Here, N in equation (2) is an integer of 1 or more.

[0060] N × S = F / 60 ... (2) In the case of equation (2) as well, it is possible to obtain an image in which the influence of positional changes of the camera 206 due to vibrations caused by the rotation of the second spindle 14-2 is suppressed.

[0061] Furthermore, in equation (2), N is not a constant value, and N may be variable during a single scan. For example, based on the relationship between the scanning position and the scanning speed V, the value of N may be made smaller near the edge portion e2 of groove g2 in Figure 10, and larger in other locations.

[0062] (Variation 1) In Modification 1, the timing intervals (T(i)-T(i-1), T(i+1)-T(i)) for the camera 206 to perform image capture were matched to the rotation period of the second spindle 14-2, thereby suppressing the effects of vibrations caused by the rotation of the second spindle 14-2.

[0063] In contrast, in Modification 1, when taking an image at a specified position in the scanning direction (Z2 direction) triggered by the control board 106, the scanning speed in the Z2 direction (scan speed) is matched to the rotation frequency to suppress the effects of vibrations caused by the rotation of the second spindle 14-2. That is, in Modification 1, the control board 106 inputs a trigger to the camera 206 to take an image based on the scanning position in the Z2 direction detected by the scale of the Z2 table.

[0064] Figure 7 shows the relationship between vibration caused by blade rotation and the scanning position (imaging position). The horizontal axis in Figure 7 represents time T, and the vertical axis represents the amplitude due to vibration. Curve C1 in Figure 7 shows the change over time of vibration caused by the rotation of the second spindle 14-2 in the second cutting section 12-2.

[0065] In the example shown in Figure 7, camera 206 captures images at each rotational period of the second spindle 14-2. As shown in Figure 7, the timing at which camera 206 reaches the capture execution position (Z(i-1), Z(i), Z(i+1)) where the trigger for capturing is input to camera 206 is synchronized with the rotational period of the second spindle 14-2. That is, the Z2 stage table is controlled (e.g., scan speed) so that camera 206 reaches the capture execution position (Z(i-1), Z(i), Z(i+1)) at each rotational period of the second spindle 14-2.

[0066] Furthermore, the camera 206 may reach the shooting position (Z(i-1), Z(i), Z(i+1)) at multiple rotational intervals of the second spindle 14-2. In other words, the interval between the timings in which the camera 206 reaches the shooting position (Z(i-1), Z(i), Z(i+1)) may be an integer multiple of the period of the rotational speed F of the second spindle 14-2.

[0067] If the pitch during scanning by camera 206 is the pulse pitch P (μm) and the scan speed of camera 206 is V (μm / sec), then the frame rate F (fps) is expressed by the following equation (3).

[0068] F = V / P ... (3) If the rotational speed of the second spindle 14-2 is S (rpm), then the following equation (4) is obtained.

[0069] S = F / 60 = V / (P × 60) ... (4) Figure 8 is a graph showing the relationship between the scan speed V (μm / sec), the frame rate F (frame / sec), and the rotational speed S (rpm) of the second spindle 14-2. The lines L1, L2, and L3 in Figure 8 represent examples where the pulse pitch P (μm) is 0.02 μm, 0.04 μm, and 0.06 μm, respectively.

[0070] Generally, the camera's frame rate F is capped at around 2000 fps, and the spindle rotation speed is 60,000 rpm or less. In the graph shown in Figure 8, the upper limit of the rotation speed S of the second spindle 14-2 is 60,000 rpm. Therefore, it is possible to determine the operating conditions (pulse pitch P, scan speed V, frame rate F, and rotation speed S of the second spindle 14-2) from the graph shown in Figure 8.

[0071] In the example shown in Figure 7, the scan pitches Z(i)-Z(i-1) and Z(i+1)-Z(i) are approximately the same. However, it is also possible to vary the scan speed V for each pitch by making the pitch P of the scanning execution position variable.

[0072] In step-cut machining, the upper first dicing groove G1 and the lower second dicing groove G2 are formed in two passes. Therefore, according to this embodiment, the kerf edge of both the first dicing groove G1 and the second dicing groove G2 can be accurately measured.

[0073] Figure 9 is a flowchart showing the inspection method for dicing grooves according to the embodiment and modified example 1.

[0074] For the upper first dicing groove G1, the kerf edge (edge ​​portion) is detected by scanning the observation unit MS, which includes the microscope 204, in the Z2 direction (step S10).

[0075] On the other hand, for the lower second dicing groove G2, as in Embodiment and Modification 1, the frame rate F is adjusted according to the rotation speed S or pulse pitch P of the second spindle 14-2, and the kerf edge (edge ​​portion) is detected by taking images while scanning the observation unit MS in the Z2 direction (for example, while moving the observation unit MS closer to the workpiece W or away from the workpiece W) (step S12).

[0076] Next, the three-dimensional shape of the groove is calculated by detecting the relative position of the lower kerf edge to the upper kerf edge (step S14). This makes it possible to detect the amount of misalignment between the upper and lower kerf edges, which can then be used to correct the cutting position.

[0077] In this embodiment, the relative position of the kerf edge of the lower second dicing groove G2 with respect to the kerf edge of the upper first dicing groove G1 was detected, but the present invention is not limited thereto. For example, instead of the kerf edge of the upper first dicing groove G1, it is also possible to use the irregularities of the device pattern to detect the relative position between the irregularities of the device pattern and the kerf edge of the second dicing groove G2.

[0078] In the embodiment and modification 1, the control board 106 generated a trigger for shooting using an encoder or scale, but the present invention is not limited thereto. For example, shooting may be performed by software or timer synchronization. In this case, the trigger is not acquired from the scanning axis (Z2 axis), and shooting is performed using an externally created trigger such as a clock from the dicing device 10 or an external device, or a trigger created by software.

[0079] In that case as with the embodiment and modification 1, noise reduction measurement can be performed by providing the frame rate as an external trigger, based on the relationship between scan speed and spindle rotation speed (see Figure 8). [Explanation of Symbols]

[0080] 10...Dicing device, 12-1...First cutting section, 12-2...Second cutting section, 14-1...First spindle, 14-2...Second spindle, 16-1...First blade, 16-2...Second blade, CT...Table, 50-1...First drive unit, 50-2...Second drive unit, MS...Observation unit, 54...Table drive unit, 100...Control device, 102...Input unit, 104...Display unit, 106...Control board

Claims

1. The steps include forming a first dicing groove on the surface of a workpiece using a first blade attached to a first cutting section, The steps include forming a second dicing groove within the first dicing groove along the first dicing groove using a second blade attached to a second cutting section separate from the first cutting section, A step of using an observation unit to detect at least one of the surface of the workpiece, the first dicing groove, and the second dicing groove, wherein the timing of photographing the at least one with the observation unit is adjusted according to the rotation period of the second blade, A method for inspecting dicing grooves equipped with [a specific feature / feature].

2. The method for inspecting a dicing groove according to claim 1, wherein the timing of taking an image with the observation unit is adjusted in synchronization with the rotation period of the second blade.

3. The method for inspecting a dicing groove according to claim 1 or 2, wherein the timing interval for taking images with the observation unit is set to an integer multiple of the rotation speed of the second blade.

4. The method for inspecting a dicing groove according to claim 1, wherein the timing at which the observation unit reaches the shooting execution position is synchronized with the rotation period of the second blade.

5. The method for inspecting a dicing groove according to claim 1 or 4, wherein the timing interval at which the observation unit reaches the shooting execution position is an integer multiple of the rotation period of the second blade.

6. A first cutting section comprising a first blade for forming a first dicing groove on the surface of a workpiece, A second cutting section comprising a second blade that forms a second dicing groove within the first dicing groove along the first dicing groove, An observation unit for detecting the surface of the workpiece, the first dicing groove, and at least one of the second dicing groove, A control unit that adjusts the timing for capturing at least one of the observation units according to the rotation period of the second blade, A dicing device equipped with the following features.

Images