Wafer processing system and wafer processing method

Abstract

A wafer processing system (10) includes a grinding section (16) that performs grinding processing on an end portion of a wafer, a measurement section (20) that measures a shape of the end portion of the wafer on which the grinding processing is performed and measures a shape of an end portion of a dresser used in the grinding processing, and a feedback calculation section (152) that performs feedback for the grinding processing based on a measurement result of the shape of the end portion of the dresser.

Description

Technical Field

[0001] This invention relates to wafer processing systems and methods, and particularly to wafer processing systems and methods for processing the shape of the ends of a wafer. Background Technology

[0002] When a circular wafer is surface-processed using a grinding apparatus, the ends of the wafer are processed into sharp points, which can lead to wafer breakage or defects. Therefore, a grinding process (also known as chamfering) is performed on the wafer to remove the sharp points at the ends and make the ends rounded or chamfered (see Patent Document 1).

[0003] The shape and dimensions of the wafer ends formed by grinding are specified by industry associations or customer requirements, thus requiring grinding within these specified ranges. Therefore, in the wafer manufacturing process, the shape of the wafer ends is measured after grinding to check whether the shape of the ends is within the specified range.

[0004] Patent Document 2 discloses a shape measuring device for measuring the shape of the end of a wafer using a light projection measurement method. This shape measuring device projects light onto the end of a ground wafer from a direction substantially parallel to the front and back surfaces of the wafer, and captures a projected image of the wafer end using a camera from a direction opposite to the light projection direction. The shape of the wafer end is then measured based on this projected image.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-78326

[0008] Patent Document 2: Japanese Patent Application Publication No. 2009-168634 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] In the grinding processes described above, sometimes the shape of the wafer's end becomes defective (e.g., deviates from the machining target). For example, the grinding stone used in the grinding process is machined into the target shape by using a dresser to cut the surface of the grinding stone (to shape the cross-section (groove)). Such a dresser will deteriorate (wear) if it is used repeatedly. If the dresser deteriorates, the grinding stone cannot be properly shaped, becoming a major cause of defective wafer end shapes.

[0011] The present invention was made in view of the following circumstances, and its object is to provide a wafer processing system and a wafer processing method capable of suppressing the generation of shape defects at the ends of the wafer after grinding.

[0012] Methods for solving problems

[0013] To achieve the above objectives, the present invention includes the following methods.

[0014] The wafer processing system of the first aspect of the present invention includes: a grinding unit that grinds the end of a wafer; a measuring unit that measures the shape of the end of the ground wafer and the shape of the end of a dresser used to maintain the grinding stone used in the grinding process; and a feedback calculation unit that provides feedback on the grinding process based on the measurement result of the shape of the end of the dresser.

[0015] The wafer processing system of the second aspect of the present invention, based on the first aspect, has a feedback calculation unit that determines whether the dresser is good or bad when the wear amount of the dresser exceeds a threshold.

[0016] The third-party wafer processing system of the present invention, based on the first or second method, when the feedback calculation unit determines that the shape of the end of the wafer is defective, the measurement unit performs the measurement of the shape of the end of the dresser; when the feedback calculation unit determines that the shape of the end of the dresser is defective, it outputs an instruction to maintain the dresser; when the feedback calculation unit determines that the shape of the end of the dresser is good, it outputs an instruction to use the dresser to maintain the grinding stone.

[0017] The wafer processing system of the fourth aspect of the present invention, based on any one of the first to third aspects, includes an output section that overlays and displays the measurement results of the wafer and the trimmer.

[0018] The wafer processing system of the fifth aspect of the present invention, based on any one of the first to fourth aspects, compares the measured value of the shape of the trimmer with the design value, and calculates the correction amount of the shape of the trimmer and the relative movement amount between the wafer and the grinding stone.

[0019] The wafer processing system of the sixth aspect of the present invention, based on any one of the first to fifth aspects, includes a measurement unit that measures the surface roughness of the grinding surface of the wafer, and a feedback calculation unit that adjusts the cutting depth of the grinding stone relative to the wafer based on the surface roughness measurement results of the grinding surface.

[0020] The seventh aspect of the wafer processing system of the present invention, based on any of the first to sixth aspects, involves a feedback calculation unit that adjusts the helical angle of the grinding stone according to the measurement results of the wafer.

[0021] In the wafer processing method of the eighth aspect of the present invention, in the measurement unit that measures the shape of the end of the wafer that has undergone grinding, the shape of the end of the dresser used in the grinding process is measured, and feedback on the grinding process is provided based on the measurement result of the shape of the end of the dresser.

[0022] Invention Effects

[0023] According to the present invention, by providing feedback based on the measurement results of the trimmer measured in the measurement section where the wafer is measured, it is possible to suppress the occurrence of defects in the shape of the wafer end after grinding. Attached Figure Description

[0024] Figure 1 It is a top view showing the general structure of a wafer fabrication system.

[0025] Figure 2 This is a schematic diagram showing the general structure of the grinding device (chamfering device) installed in the grinding section.

[0026] Figure 3 This is a side view showing the general structure of the shape measuring device.

[0027] Figure 4 This is a top view showing the outline structure of the shape measuring device.

[0028] Figure 5 This is a schematic diagram showing the detailed structure of the optical unit.

[0029] Figure 6 This is a functional block diagram of the control device in the shape measuring apparatus.

[0030] Figure 7 This is a cross-sectional view showing an example of the shape of the end of the trimmer.

[0031] Figure 8 This is a flowchart illustrating the wafer fabrication method of Example 2.

[0032] Figure 9 This is a diagram showing an example of the output of the measurement results of the wafer and the trimmer.

[0033] Figure 10 This diagram illustrates the main causes of wafer shape defects.

[0034] Figure 11 This is a cross-sectional view of the wafer after grinding.

[0035] Figure 12 This is a diagram used to illustrate the adjustment of the helix angle. Detailed Implementation

[0036] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0037] [Wafer Processing System]

[0038] Figure 1 This is a top view showing the general structure of the wafer fabrication system 10. It should be noted that, in the following description, the X and Z directions of the three mutually orthogonal XYZ directions shown in the figure refer to the horizontal direction, and the Y direction refers to the vertical direction.

[0039] like Figure 1 As shown, the wafer processing system 10 includes a housing section 12, a loading section 14, a grinding section 16, a cleaning section 18, a measuring section 20, and a transport section 22.

[0040] The loading unit 14 transports the wafer W between the housing unit 12, the grinding unit 16, and the measuring unit 20. Figure 2 as well as Figure 3 (See diagram below). This action is performed by a supply recycling robot. A wafer box is provided in the box section 12 to hold multiple wafers W that have undergone chamfering. The supply recycling robot removes the wafers W one by one from the wafer box, or stores the chamfered wafers W into the wafer box.

[0041] The supply and recycling robot has a 3-axis rotating transport arm with an adsorption pad (not shown) on its upper surface. The transport arm uses this adsorption pad to vacuum-adsorb the lower surface of the wafer W, thus holding the wafer W in place. That is, the transport arm of the supply and recycling robot can move back and forth, lift and drop, and rotate while holding the wafer W, and the wafer W is transported by combining these actions.

[0042] The grinding section 16 performs grinding processing on the end of the wafer W, that is, from roughing to finishing.

[0043] Figure 2 This is a schematic structural diagram showing the general structure of the grinding device (chamfering device) 30 installed in the grinding section 16. (See diagram for reference.) Figure 2 As shown, the grinding apparatus 30 includes a grinding table 32 for holding the wafer W, a grinding stone 34, and a spindle motor 36 for rotating the grinding stone 34.

[0044] The grinding table 32 has a holding surface 32a on its upper surface for holding and holding the wafer W. The grinding table 32 is configured to rotate about a rotation axis P parallel to the Y direction using various actuators such as a motor drive mechanism (not shown).

[0045] The grinding stone 34 is configured to rotate around a rotation axis parallel to the Y direction using a spindle motor 36. Furthermore, the grinding stone 34 moves forward and backward along the Z direction relative to the end of the wafer W held on the grinding table 32. During the forward movement of the grinding stone 34, the rotating grinding stone 34 presses against the outer periphery (edge ​​portion 80) of the rotating wafer W, performing grinding on the outer periphery of the wafer W. In this example, the grinding stone 34 is a shaped grinding stone with grinding grooves 34a on its outer periphery, and during grinding, the shape of the grinding grooves 34a is transferred onto the outer periphery of the wafer W.

[0046] In the grinding apparatus 30, in addition to the aforementioned grinding stone (rough grinding stone) 34, a fine grinding stone (not shown) is also provided. Thus, after rough machining of the outer periphery of the wafer W using the grinding stone 34, chamfering machining for fine grinding of the outer periphery of the wafer W is performed using the fine grinding stone. Furthermore, the grinding apparatus 30 is equipped with a tool for grinding the groove portion 82 (see reference...) Figure 4 The grinding unit 16 includes a rough grinding stone for rough grinding of the groove and a fine grinding stone for grinding the groove. Therefore, for the groove portion 82, after rough grinding with the rough grinding stone, a chamfering process is performed as a finishing grinding using the fine grinding stone. It should be noted that multiple grinding units 30 may also be provided in the grinding unit 16.

[0047] return Figure 1 The cleaning unit 18 cleans the wafer W after chamfering. The cleaning unit 18 is equipped with a rotary cleaning device (not shown). The rotary cleaning device rotates the wafer W held by the cleaning table while spraying cleaning fluid onto the upper surface (surface) of the wafer W to remove dirt adhering to the upper surface of the wafer W.

[0048] The transport unit 22 transports wafers W between the grinding unit 16 and the cleaning unit 18. The transport unit 22 includes a transport robot configured to perform linear motion in the Z-direction and vertical lifting motion in the Y-direction (vertical direction). The transport robot has an arm with an adsorption pad at its front end. The transport robot transports the wafer W while adsorbing its upper surface using the adsorption pad on its arm. Thus, in the transport unit 22, the transport robot transports wafers W that have undergone chamfering in the grinding unit 16 to the cleaning unit 18, or transports wafers W that have been cleaned in the cleaning unit 18 to the grinding unit 16.

[0049] The measurement unit 20 performs thickness measurement and pre-alignment of the wafer W undergoing chamfering. The measurement unit 20 is equipped with a measurement stage (in...) for performing thickness measurement and pre-alignment of the wafer W. Figure 4 The figure shows a thickness sensor and a flat / groove detection sensor (illustrated by reference numeral 102 in the attached figure).

[0050] The measuring stage rotates the wafer W around its central axis. A thickness sensor, such as a capacitive sensor, measures the distance from the upper surface to the lower surface of the wafer W. The measurement result from the capacitive sensor is output to a computing device (not shown) to determine the thickness of the wafer W. An edge / groove detection sensor, such as a laser sensor, detects the position of the edge or groove of the wafer W. Here, an edge is a flat portion formed at the end of the wafer W to indicate its crystal orientation; a groove 82 is a notch formed to indicate the crystal orientation of the wafer. Examples of thickness sensors include, in addition to capacitive sensors, interferometric thickness sensors, and image sensors, etc., for edge / groove detection.

[0051] In addition, the measuring unit 20 includes a diameter measuring device (not shown) for measuring the diameter of the chamfered wafer W and a shape measuring device 100 for measuring the three-dimensional shape of the end of the chamfered wafer W (an example of the "shape measuring device" of the present invention). The structure of the shape measuring device 100 will be described in detail later.

[0052] Next, a summary of the operation of the wafer processing system 10 according to the embodiment will be described.

[0053] First, the wafer W is taken out of the cassette installed in the cassette section 12 by the supply and recovery robot of the loading section 14 and transported to the measurement section 20. The wafer W transported to the measurement section 20 is placed on the measurement worktable of the measurement section 20.

[0054] Next, in the measurement unit 20, a thickness sensor and a flat / groove detection sensor are used to measure and pre-align the thickness of wafer W. Additionally, a diameter measuring device is used to measure the diameter of wafer W.

[0055] Next, the wafer W, which has undergone various measurements in the measurement unit 20, is transported to the grinding unit 16 by the supply and recovery robot in the loading unit 14. The wafer W transported to the grinding unit 16 is placed on the grinding table 32 of the grinding apparatus 30.

[0056] Next, in the grinding section 16, grinding (chamfering) of the end of the wafer W is performed using the grinding apparatus 30. Specifically, after roughing the edge portion 80, which is the outer periphery of the wafer W, using the grinding stone 34, chamfering is performed for the finishing grinding of the outer periphery of the wafer W using a fine grinding stone. Furthermore, for the groove portion 82 of the wafer W, after roughing using a groove rough grinding stone, chamfering is performed for the finishing grinding using a groove fine grinding stone.

[0057] like Figure 1As shown, a grinding wheel motor 24 and a wafer / grinding wheel position control unit 26 are provided in the grinding section 16. The grinding wheel motor 24 is a motor for rotating the grinding wheel 34 and the fine grinding wheel according to a control signal from the device control unit 200. The wafer / grinding wheel position control unit 26 includes actuators for adjusting the relative positions (XYZ direction positions and the tilt (helix angle) of the wafer W, the grinding wheel 34, and the fine grinding wheel relative to the wafer W) according to the control signal from the device control unit 200. It should be noted that... Figure 1 The device control unit 200 shown may be included in the control device 110, which includes the measurement control unit 160, or it may be included in a circuit or control device different from the control device 110. The measurement control unit 160, etc., will be described later.

[0058] Next, the wafer W, which has undergone grinding (beveling) in the grinding section 16, is transported from the grinding section 16 to the cleaning section 18 by the transport robot of the transport section 22. Then, in the cleaning section 18, the wafer W is cleaned using a rotary cleaning device.

[0059] Next, the wafer W, having completed cleaning in the cleaning section 18, is transported from the cleaning section 18 to the grinding section 16 by the transport robot of the transport section 22. Afterwards, the wafer W is transported from the grinding section 16 to the measurement section 20 by the supply and recovery robot of the loading section 14. The wafer W transported to the measurement section 20 is then placed on the measurement worktable.

[0060] Next, in the measuring unit 20, the diameter of the wafer W is measured using a diameter measuring device, and the three-dimensional shape of the end of the wafer W is measured using a shape measuring device 100. The measurement results (diameter of the wafer W and three-dimensional shape of the end of the wafer W) from the measuring unit 20 are sent to the output unit (in... Figure 6 The output is shown in the attached drawing (illustrated by reference numeral 114). It should be noted that the control device 110 described later can also calculate a judgment result indicating whether the measurement result of the measuring unit 20 is within a preset specified range, and output the judgment result to the output unit.

[0061] Next, the wafer W, which has completed the measurement in the measurement unit 20, is transported from the measurement unit 20 to the box unit 12 by the supply and recycling robot of the loading unit 14 and housed in the box.

[0062] [Shape measuring device]

[0063] Next, the structure of the shape measuring device 100 will be described. The shape measuring device 100 calculates three-dimensional shape data representing the height information (surface shape, surface roughness, etc.) of the measured surface at the end of the wafer W, which is the object of measurement, based on multiple images captured at regular intervals while scanning along the scanning direction (Z direction) by the optical unit 104 (described later).

[0064] Figure 3 This is a side view (viewed from the X direction) showing the outline structure of the shape measuring device 100. Figure 4 This is a top view (viewed from the Y direction) showing the outline structure of the shape measuring device 100.

[0065] like Figure 3 and Figure 4 As shown, the shape measuring device 100 includes a measuring stage 102, an optical unit 104, and a control device 110.

[0066] The measurement stage 102 has a holding surface 102a on its upper surface for adsorbing and holding the wafer W. Furthermore, the measurement stage 102 is configured to rotate about a rotation axis G parallel to the Y direction. The stage drive unit 116, composed of various actuators such as a motor drive mechanism, rotates the measurement stage 102 about the rotation axis G under the control of the control device 110 (described later). As a result, the wafer W adsorbed and held on the holding surface 102a of the measurement stage 102 rotates and moves about the rotation axis G.

[0067] The optical unit 104 is constructed using a white light interference microscope. This optical unit 104 is positioned on one side of the measurement stage 102 in the Z direction (…). Figure 3 The optical unit 104 is positioned adjacent to the left side of the wafer W. Specifically, the optical axis R (corresponding to the optical axis of the interference lens 124) is arranged parallel (including substantially parallel) to the main surface (upper or lower surface) of the wafer W. In other words, the optical axis R of the optical unit 104 is arranged parallel (including substantially parallel) to the direction orthogonal to the rotation axis G of the measurement stage 102 (preferably, intersecting the rotation axis G of the measurement stage 102). Furthermore, the optical unit 104 photographs the end (edge ​​portion 80 or groove portion 82) of the wafer W from a position opposite to the end of the wafer W held on the measurement stage 102.

[0068] Next, the structure of the optical unit 104 will be described in detail. Figure 5 This is a schematic diagram showing the detailed structure of the optical unit 104.

[0069] Optical unit 104 is a Michelson-type white light interference microscope. This optical unit 104 is as follows... Figure 5As shown, the device includes a light source 120, a beam splitter 122, an interference objective lens 124, an imaging lens 126, and a camera 128. The interference objective lens 124, beam splitter 122, imaging lens 126, and camera 128 are arranged sequentially along the left side of the wafer W, which is the object of measurement, in the Z direction. Furthermore, the light source 120 is positioned opposite the beam splitter 122 in the Y direction.

[0070] Under the control of the control device 110, the light source 120 emits a parallel beam of white light (low coherence light) towards the beam splitter 122 as the measurement light L1. Although not shown in the figure, the light source 120 includes a light source capable of emitting the measurement light L1, such as a light-emitting diode, a semiconductor laser, a halogen lamp, or a high-brightness discharge lamp, and a condensing lens that converts the measurement light L1 emitted from the light source into a parallel beam.

[0071] Beam splitter 122 is, for example, a semi-transparent mirror. Beam splitter 122 reflects a portion of the measurement light L1 incident from light source 120 toward the interferometer objective 124 on the right side of the Z direction. In addition, beam splitter 122 causes a portion of the composite light L3 (described later) incident from interferometer objective 124 to pass through to the left side of the Z direction and exits the composite light L3 toward imaging lens 126.

[0072] The interference objective 124 is Michelson type and includes objective 124A, beam splitter 124B, and reference plane 124C. Beam splitter 124B and objective 124A are arranged sequentially to the left along the Z direction from the side of the plane being measured. Reference plane 124C is positioned opposite beam splitter 124B in the Y direction. Hereinafter, a Michelson type interference optical system will be used, but the interference optical system is not limited to Michelson type; known interference optical systems such as Mirau type or Linnik type can be used.

[0073] Objective lens 124A has a light-focusing function, which allows the measurement light L1 incident from beam splitter 122 to be focused onto the surface to be measured through beam splitter 124B.

[0074] Beam splitter 124B uses, for example, a semi-reflective mirror. Beam splitter 124B splits a portion of the measurement light L1 incident from objective lens 124A into reference light L2, allowing the remaining measurement light L1 to pass through and exit toward the surface being measured, while reflecting the reference light L2 toward reference surface 124C. After illuminating the surface being measured, the measurement light L1 transmitted through beam splitter 124B is reflected back to beam splitter 124B by the surface being measured.

[0075] The reference surface 124C is, for example, a mirror, which reflects the reference light L2 incident from the beam splitter 124B toward the beam splitter 124B. The position of the reference surface 124C in the Y direction can be manually adjusted using a position adjustment mechanism (not shown, such as a ball screw mechanism, actuator, etc.). This allows for adjustment of the optical path length (reference optical path length) of the reference light L2.

[0076] Beam splitter 124B generates a composite beam L3 consisting of the measurement beam L1 returning from the measured surface and the reference beam L2 returning from the reference surface 124C, and emits the composite beam L3 toward the objective lens 124A to the left in the Z direction. The composite beam L3 passes through the objective lens 124A and the beam splitter 122 and is incident on the imaging lens 126.

[0077] Imaging lens 126 images the composite light L3 incident from beam splitter 122 onto the imaging plane of camera 128 (not shown). Specifically, imaging lens 126 images a point on the focal plane of objective lens 124A as an image point on the imaging plane of camera 128.

[0078] Although not shown in the diagram, camera 128 has a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) imaging element. Camera 128 captures the composite light L3 imaged onto the imaging surface of the imaging element by imaging lens 126, and processes the imaging signal of the composite light L3 obtained by the imaging to output an imaging signal. Camera 128 is an example of an imaging unit.

[0079] The optical unit drive unit 106 is composed of various actuators such as a linear motor or a motor drive mechanism, and holds the optical unit 104 so that it can move freely along the Z direction, which is the scanning direction. Under the control of the control device 110, the optical unit drive unit 106 scans the optical unit 104 along the Z direction, that is, in a direction parallel to the optical axis R of the optical unit 104. The optical unit drive unit 106 is an example of a relative movement unit.

[0080] Furthermore, the optical unit drive unit 106 keeps the optical unit 104 movable not only along the Z direction, but also along the Y and X directions. This allows adjustment of the relative position (relative position in the X and Y directions) of the optical unit 104 relative to the end of the wafer being measured. Additionally, when the measurement field of view of the measured surface can be limited at one time due to limitations such as the measurement field of view of the interference objective 124, multiple measurements can be performed while moving the optical unit 104 along the X or Y direction. It should be noted that, instead of moving the optical unit 104 along the X, Y, or Z directions, the measurement stage 102 can also be moved along the X, Y, or Z directions.

[0081] The scale 130 is a position detection sensor that detects the Z-direction position of the optical unit 104, for example, a linear scale. The scale 130 repeatedly detects the Z-direction position of the optical unit 104 and repeatedly outputs the position detection results to the control device 110.

[0082] Figure 6 This is a functional block diagram of the control device 110 in the shape measuring device 100. The control device 110 is connected to the light source 120 of the optical unit 104, the camera 128, the scale 130, the stage drive unit 116, the optical unit drive unit 106, the operation unit 112, and the output unit 114.

[0083] The operation unit 112 includes an input device (such as a keyboard and mouse) for accepting the operator's operation input to the control device 110.

[0084] The output unit 114 is a device for outputting data such as the execution results and calculation results of the program executed by the control device 110. The output unit 114 may include, for example, an operation UI (user interface) and a monitor (such as an LCD) for displaying the detection results. Alternatively, the output unit 114 may be based on or replace a monitor, and may include a printer or a speaker.

[0085] The control device 110 controls the measurement operation of the three-dimensional shape of the measured surface (edge ​​portion 80 or groove portion 82) performed by the shape measuring device 100 according to the operation input from the operation unit 112, and performs calculations on the three-dimensional shape of the measured surface. The control device 110 includes a processor (such as CPU (Central Processing Unit), GPU (Graphics Processing Unit), etc.) that performs various operations, memory (such as ROM (Read Only Memory) and RAM (Random Access Memory), etc.) that serves as the working area of ​​the processor, and storage devices (such as SSD (Solid State Drive) or HDD (Hard Disk Drive), etc.) for storing various programs and data.

[0086] The control device 110 functions as a shape / roughness analysis unit 150, a feedback calculation unit 152, and a measurement control unit 160 by using a processor to execute a program stored in a storage device.

[0087] The measurement control unit 160 controls the stage drive unit 116, the optical unit drive unit 106, the light source unit 120, and the camera 128. While the optical unit 104 scans along the scanning direction (Z direction), the camera 128 repeatedly captures images of the measured surface (edge ​​80 or groove 82) of the object at regular intervals. Specifically, the measurement control unit 160 controls the stage drive unit 116 to rotate the measurement stage 102 so that the measured surface (edge ​​80 or groove 82) of the object is positioned opposite the optical unit 104. Furthermore, after the measurement light L1 from the light source unit 120 begins to be emitted, the measurement control unit 160 controls the optical unit drive unit 106 to scan the optical unit 104 along the Z direction. In addition, during the period when the optical unit drive unit 106 scans the optical unit 104 along the Z direction, the measurement control unit 160, based on the detection result of the Z direction position of the optical unit 104 detected by the scale 130, repeatedly performs the capture of the composite light L3 by the camera 128 and the output of the captured image to the control device 110 whenever the optical unit 104 moves a certain distance along the Z direction.

[0088] Whenever the camera 128 captures combined light L3, the shape / roughness resolution unit 150 acquires the captured image output from the camera 128 and generates three-dimensional shape data of the measured surface of the object to be measured (wafer W). In addition, the shape / roughness resolution unit 150 generates three-dimensional shape data of the end of the trimmer by placing a trimmer on the measurement stage 102 of the measurement unit 20.

[0089] The feedback calculation unit 152 performs feedback control based on the measurement results of the shape / roughness analysis unit 150.

[0090] [Example 1]

[0091] Previously, detecting dresser deterioration (measuring wear) required off-machine measurement using a device different from the wafer grinding section, making dresser deterioration detection a cumbersome process. Therefore, to avoid this cumbersome process, a dresser replacement management system was implemented, where dressers are replaced at predetermined time points after a specified number of grinding stones have been used.

[0092] However, when all dressers are replaced based on quantity management regardless of their actual deterioration, there are instances where dressers that have not deteriorated become the ones to be replaced.

[0093] Therefore, in Example 1, the dresser is measured periodically in the wafer processing system 10. For example, from the start of operation of the wafer processing system 10, at certain intervals, whenever the number of times the dresser is used to process the grinding stone 34 or the fine grinding stone reaches a predetermined number, the dresser is transported to the measuring unit 20 and the shape of the end of the dresser is measured.

[0094] Figure 7 This is a cross-sectional view showing an example of the shape of the end of the trimmer. The measured shape T of the trimmer TR, as measured by the shape measuring device 100, is shown. A Relative to target shape T T The amount of wear (deviation in the Y direction and the maximum value of the deviation) is denoted as dy.

[0095] The shape / roughness analysis unit 150 generates three-dimensional shape data of the end of the dresser TR and calculates the wear amount dy.

[0096] Based on the measurement results from the shape / roughness analysis unit 150, if the wear amount dy exceeds a threshold (e.g., 5 μm), the feedback calculation unit 152 outputs (e.g., displays) in the output unit 114 the information indicating that the dresser TR needs to be replaced, or the processing of the wafer W needs to be stopped. It should be noted that the threshold is not limited to the above; for example, the dresser TR may also be judged as defective (NG) if the ratio of dy to the thickness Dy of the wafer W is above the threshold (1% in one example).

[0097] According to Example 1, by periodically measuring the wear condition of the dresser, the wear condition of the dresser can be parameterized and evaluated numerically. This reduces maintenance waste of the dresser TR and prevents the need to replace dressers TR that have not yet deteriorated. Furthermore, according to Example 1, the probability of wafer W processing defects can be reduced, thereby improving processing reliability.

[0098] [Example 2]

[0099] If the shape measurement result of wafer W is unacceptable (NG), the cause should be identified and rectified as soon as possible. When the shape of wafer W is NG, consider the following approach: After grinding wafer W with the dressing tool TR and grinding stone 34 or a fine grinding stone, perform grinding on wafer W again to measure wafer W. Furthermore, if the second measurement result is also NG, replace the dressing tool TR, etc.

[0100] However, in the above-mentioned solutions, if the dresser TR is faulty, the process from grinding stone maintenance to reassessment becomes wasteful.

[0101] Therefore, in Example 2, the trimmer TR is measured when the shape of the wafer W is NG. This eliminates the waste associated with grinding stone maintenance.

[0102] Figure 8 This is a flowchart illustrating the wafer fabrication method of Example 2.

[0103] like Figure 8 As shown, in Example 2, firstly, the shape of the end of the wafer W is measured by the shape measuring device 100 (step S10). Then, if the measurement result of the wafer W is NG, the grinding stone 34 that has ground the wafer W or the dressing device TR used for the maintenance (dressing) of the grinding stone for fine grinding is transported to the measuring unit 20, and the shape of the end of the dressing device TR is measured by the shape measuring device 100 (step S12).

[0104] Next, if the shape of the end of the dresser TR is good (OK), the dresser TR is used for maintenance of the grinding stone 34 or the fine grinding stone (step S14). On the other hand, if the shape of the end of the dresser TR is bad (NG), the dresser TR is maintained (step S16). For example, the feedback calculation unit 152 notifies the operator via the output unit 114 (e.g., a display urging the replacement of the dresser TR, etc.), and no dressing is performed.

[0105] According to Embodiment 2, the process of re-measuring wafer W from trimming can be omitted, thus allowing the main causes of shape defects in wafer W to be determined in advance. Furthermore, according to Embodiment 2, since trimming of the defective trimmer TR is not performed, no damage is caused to the grinding stone 34 or the fine grinding stone. Therefore, the operating cost of the wafer processing system 10 can be reduced.

[0106] [Example 3]

[0107] As described above, in the wafer processing system 10, the shape of the dresser TR is transferred to the grinding stone 34 or a fine grinding stone, and the wafer W is ground using the grinding stone 34 or the fine grinding stone. Therefore, the wafer W and the dresser TR are preferably as close in shape as possible, and more preferably the same shape.

[0108] Therefore, in Embodiment 3, a user interface (UI) is provided that displays the measurement results of the wafer W and the trimmer TR on the output unit 114 in an overlapping manner.

[0109] exist Figure 9 In the example shown, the measurement results (cross-sectional shape) of wafer W and trimmer TR are displayed overlaid. It should be noted that the dimensions of wafer W and trimmer TR (e.g., Y-direction dimension, tilt angle, etc.) or the deviation in the Y-direction (e.g., the maximum deviation) δ can also be displayed.

[0110] According to Example 3, the operator can confirm the difference between the shape of wafer W and the shape of trimmer TR based on the UI described above. This allows the operator to determine whether the shape of trimmer TR has been accurately transferred to wafer W. Furthermore, in cases where the shape of wafer W is disordered, it is possible to determine whether there is a problem with trimmer TR.

[0111] It should be noted that the processing conditions of wafer W (such as the feed rate in the Z direction) can also be displayed. In this case, by comparing the shape of the dresser TR and the feed rate information in the Z direction with the wafer W, the cause of the defect in wafer W can be determined.

[0112] [Variation Example 1]

[0113] Furthermore, there are cases where the upper and lower surfaces of the edge portion 80 of the wafer W are divided into upper and lower sides for processing by moving the relative position of the grinding stone 34 and the wafer W in the Y direction (up and down). In this case, it is impossible to determine whether the shape defect of the wafer W is caused by the movement in the Y direction or by the shape of the grinding stone 34 (trimming). For example, if trimming is performed when the defect is caused by the movement in the Y direction, the trimmer TR will deviate from the actual shape of the wafer W, and the processing accuracy of the wafer W will decrease.

[0114] Figure 10This diagram illustrates the main causes of wafer shape defects. Figure 10 (a) shows the actual shape of wafer W due to wear of the dresser TR. A From the target shape W T Examples of deviation. Figure 10 (b) represents the relative target movement of the grinding stone with respect to the wafer W, 34 T In comparison, the actual movement was 34. A An example where the wafer W is too large, causing it to deviate from the target shape (become thinner).

[0115] Therefore, in Modification 1, the feedback calculation unit 152 independently calculates the correction amount and Y-direction movement amount of the trimmer TR by comparing the measured value and the design value of the shape of the trimmer TR. For example, if a shape defect is detected in the wafer W, the trimmer TR is measured in the measurement unit 20. Furthermore, if the feedback calculation unit 152 determines that the difference between the measured value and the design value of the shape is above a threshold, the shape of the trimmer TR can be corrected or the trimmer TR can be replaced based on this difference. On the other hand, if the feedback calculation unit 152 determines that the difference is less than the threshold, the wafer / grindstone position control unit 26 can be controlled by the device control unit 200 to adjust the relative movement amount between the wafer W and the grinding stone based on this difference. Furthermore, after these adjustments, the goodness or badness of the shape of the wafer W can be determined again.

[0116] According to Modification 1, the shape of the dresser TR and the relative movement of the wafer W and the grinding stone can be appropriately modified respectively.

[0117] Furthermore, as described above, in this embodiment, since the same measuring unit 20 is used to measure the wafer W and the trimmer TR, systematic errors are less likely to affect the measurement results, and high-precision correction of the movement amount can be performed.

[0118] [Modification Example 2]

[0119] In addition, the greater the depth of cut (the amount of movement in the Z direction) of the grinding stone 34 relative to the wafer W, the higher the processing efficiency, but the rougher the grinding surface of the wafer W (hereinafter referred to as the processing surface).

[0120] Therefore, in Modified Example 2, the roughness of the processed surface of the wafer W is measured by the shape measuring device 100. Then, the feedback calculation unit 152 provides feedback on the cutting depth of the grinding stone 34 based on the roughness measurement result. For example, if the roughness of the processed surface of the wafer W increases, the feedback calculation unit 152 controls the wafer / grind stone position control unit 26 via the device control unit 200 to adjust at least one of reducing the cutting depth and increasing the rotational speed of the spindle motor 36.

[0121] According to Modification Example 2, by utilizing the roughness measurement results of wafer W, processing can be performed with the maximum cutting depth that achieves the target roughness, depending on the state of the grinding stone. This contributes to improving the economic efficiency of the wafer processing system 10.

[0122] [Modification Example 3]

[0123] Figure 11 This is a cross-sectional view of the wafer W after grinding. (Example) Figure 11 As shown, on the edge portion 80 of the wafer W after grinding, a generally flat portion W1 along the Y direction and an inclined portion W2 from the Y direction (upper and lower) ends of the generally flat portion W1 toward the surface and back of the wafer W respectively are formed according to the shape of the grinding stone 34.

[0124] In Modification 3, the feedback calculation unit 152 compares the roughness of the inclined surface W2 with the roughness of the generally flat surface W1, and feeds back the comparison result to the processing conditions of the wafer W. For example, the inclined surface W2 of the wafer W is easily subjected to processing stress, so the surface tends to become rough. On the other hand, the generally flat surface W1 tends to have relatively stable roughness.

[0125] In view of the above-described properties, when the roughness of the generally flat portion W1 increases, the feedback calculation unit 152 controls the wafer / grinding stone position control unit 26 via the device control unit 200 to adjust the cutting depth of the grinding stone 34 or the rotational speed of the spindle motor 36. Specifically, by reducing the cutting depth of the grinding stone 34 or increasing the rotational speed of the spindle motor 36, the coarsening of the generally flat portion W1 can be suppressed.

[0126] On the other hand, when the roughness of the inclined surface W2 increases, the feedback calculation unit 152 performs the repair, and outputs the content to the output unit 114 to urge the operator to perform repair or replace the repairer TR.

[0127] According to Modification Example 3, the wafer W can be processed under optimal processing conditions based on the roughness of the generally planar portion W1 and the inclined portion W2 of the wafer W.

[0128] [Variation Example 4]

[0129] Furthermore, when the grinding stone 34 is tilted relative to the wafer W during processing, the helical angle can be corrected based on the measurement results of the wafer W by the shape measuring device 100.

[0130] For example, it is believed that changing the helix angle alters the shape or improves the roughness of the processed surfaces (W1 and W2) of wafer W. Therefore, as... Figure 12As shown, the feedback calculation unit 152 can also control the wafer / grindstone position control unit 26 via the device control unit 200 to adjust the helical angle when the shape or roughness of the processing surface of the wafer W deteriorates.

[0131] According to this embodiment, by providing feedback based on the measurement results of wafer W or trimmer TR, wafer W can be processed under optimal conditions. Furthermore, the need for maintenance can be immediately communicated to the operator via output unit 114, thereby reducing processing defects.

[0132] Furthermore, according to this embodiment, since the trimmer TR and the wafer W are measured using the same measurement unit 20, the influence of systematic errors of the measurement unit 20 can be suppressed during feedback.

[0133] In the above embodiment, the structure of a shape measuring device having a white light interference microscope in the measuring unit 20 is described as an example, but it is not limited to this. For example, it may also include a shape measuring device for a microscope with a focal point changing mode or a laser confocal mode, or a shape measuring device using a light projection measuring method.

[0134] The embodiments of the present invention have been described above, but the present invention is not limited to the above examples. Of course, various improvements and modifications can be made without departing from the spirit of the present invention.

[0135] Explanation of reference numerals in the attached figures

[0136] 10…Wafer processing system, 12…Box section, 14…Loading section, 16…Grinding section, 18…Cleaning section, 20…Measuring section, 22…Transfer section, 24…Grinding stone motor, 26…Wafer / grinding stone position control section, 30…Grinding device, 32…Grinding table, 32a…Holding surface, 34…Grinding stone, 34a…Grinding groove, 36…Spindle motor, 80…Edge section, 82…Groove section, 100…Shape measuring device, 102…Measuring table, 102a…Holding surface, 104…Optical… Learning unit, 106… Optical unit drive unit, 110… Control device, 112… Operation unit, 114… Output unit, 116… Stage drive unit, 120… Light source unit, 122… Beam splitter, 124… Interference objective lens, 124A… Objective lens, 124B… Beam splitter, 124C… Reference surface, 126… Imaging lens, 128… Camera, 130… Scale, 150… Shape / roughness resolution unit, 152… Feedback calculation unit, 160… Measurement control unit, 200… Device control unit.

Claims

1. A wafer fabrication system, wherein, The wafer processing system includes: The grinding section performs grinding operations on the ends of the wafer; The measuring unit measures the shape of the end of the wafer after the grinding process and measures the shape of the end of the dresser, which is used to maintain the grinding stone used in the grinding process. as well as The feedback calculation unit provides feedback on the grinding process based on the measurement results of the shape of the end of the dresser.

2. The wafer processing system according to claim 1, wherein, The feedback calculation unit determines whether the dresser is in good condition or not when the wear of the dresser exceeds a threshold.

3. The wafer processing system according to claim 1 or 2, wherein, If the feedback calculation unit determines that the shape of the wafer's end is defective, the measurement unit measures the shape of the trimmer's end. If the feedback calculation unit determines that the shape of the end of the trimmer is defective, it will output an instruction to urge the trimmer to be maintained. If the feedback calculation unit determines that the shape of the end of the dresser is good, it will urge the use of the dresser to maintain the output of the grinding stone.

4. The wafer processing system according to any one of claims 1 to 3, wherein, The wafer processing system includes an output unit that overlays and displays the measurement results of the wafer and the trimmer.

5. The wafer processing system according to any one of claims 1 to 4, wherein, The feedback calculation unit compares the measured value of the shape of the dresser with the design value, and calculates the correction amount of the shape of the dresser and the relative movement amount of the wafer and the grinding stone.

6. The wafer processing system according to any one of claims 1 to 5, wherein, The measuring unit measures the surface roughness of the ground surface of the wafer. The feedback calculation unit adjusts the depth of cut of the grinding stone relative to the wafer based on the surface roughness measurement results of the grinding surface.

7. The wafer processing system according to any one of claims 1 to 6, wherein, The feedback calculation unit adjusts the helical angle of the grinding stone based on the measurement results of the wafer.

8. A wafer fabrication method, wherein, In the measurement unit that measures the shape of the end of a wafer that has undergone grinding, the shape of the end of the dresser used in the grinding process is measured. Feedback on the grinding process is provided based on the measurement results of the shape of the end of the dresser.

Images