Wafer processing apparatus, cleaning apparatus, and cleaning method

Abstract

To prevent a processed waste from adhering to a wafer outer peripheral part and prevent the wafer outer peripheral part from being damaged.SOLUTION: A washing method of washing a wafer W comprises: a preparation step of rotating a spinner table 10 holding the wafer W on a holding surface 11a by using a center of the holding surface 11a as an axis, and positioning a two-fluid nozzle 30 so that two fluids ejected from the two-fluid nozzle 30 are landed onto water at a center of the holding surface 11a; an upper surface washing step of moving the two-fluid nozzle 30 in a radial direction of the wafer W at a predetermined speed while ejecting the two fluids from the two-fluid nozzle 30, and washing an upper surface of the wafer W held on the holding surface 11a; and an outer peripheral washing step of washing an outer peripheral upper surface and an outer peripheral side surface of the wafer W by moving the two-fluid nozzle 30 to a position where the two fluids ejected from the two-fluid nozzle 30 moved in the radial direction of the wafer W come into contact with the outer periphery of the wafer W, and stopping the two-fluid nozzle 30 that brings the two fluids into contact with the outer peripheral upper surface and the outer peripheral side surface of the wafer W, for a predetermined time.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a wafer processing apparatus, a wafer cleaning apparatus, and a cleaning method for cleaning a processed wafer by jetting a two-fluid of water and air.

Background Art

[0002] In the manufacturing process of semiconductor devices such as ICs and LSIs used in electronic devices, in order to miniaturize and lighten the semiconductor devices, the back surface of the wafer is ground and the wafer is thinned to a predetermined thickness. In particular, in recent years, in order to meet the requirements such as thinning and miniaturization of electronic devices, it has been required to form semiconductor devices thinly.

[0003] However, a saw mark (grinding mark) is generated on the grinding surface of the ground wafer, and this saw mark causes a decrease in the flexural strength of the wafer. For this reason, the grinding surface of the wafer is polished by polishing using a polishing pad to remove the saw marks generated on the grinding surface of the wafer. For example, Patent Document 1 proposes a processing strain removing apparatus that facilitates cleaning of the polished wafer by polishing the grinding surface of the wafer using a dry polishing pad. Here, in the grinding and polishing of the wafer, a protective tape is adhered to the pattern surface of the wafer (the surface opposite to the grinding surface and the polishing surface), and the wafer is held on the holding surface of the chuck table via the protective tape.

[0004] Incidentally, when the grinding surface of a wafer is polished, polishing debris adheres to the outer edge of the wafer, that is, the outer edge of the protective tape. Therefore, the wafer is cleaned to remove this polishing debris. This wafer cleaning is performed by spraying a two-fluid mixture of water and air onto the wafer from above the wafer, which is held on a spinner table, using a two-fluid nozzle. Specifically, the spinner table holding the wafer is rotated at a predetermined speed, and the two-fluid nozzle, positioned above the center of the wafer, is moved radially toward the outer edge of the wafer to clean the upper surface of the wafer. Then, the two-fluid nozzle is moved back and forth radially along the outer edge of the wafer to clean the outer edge of the wafer. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2003-053662 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, when the two-fluid nozzle is moved back and forth in the radial direction of the wafer at the outer edge, the two fluids bounced off the spinner table, applying a force that tries to pull the wafer away from the spinner table at the outer edge, which can cause cracks or other damage to the outer edge of the wafer.

[0007] Furthermore, if polishing debris adheres to the outer edge of the wafer, in the next cutting process, when the protective tape is peeled off the wafer, which is supported by the ring frame by the dicing tape, the polishing debris adheres to the patterned surface on the wafer where the device is formed, causing problems during wafer cutting.

[0008] The present invention has been made in view of the above problems, and its object is to provide a wafer processing apparatus, a cleaning apparatus, and a cleaning method that can prevent processing debris from adhering to the outer periphery of the wafer and prevent damage to the outer periphery of the wafer. [Means for solving the problem]

[0009] The present invention, which solves the above problems, is a wafer cleaning apparatus for cleaning wafers, wherein the wafer Spinner holding surface A spinner table that is held by the Spinner holding surface A rotating means for rotating the spinner table around its center as an axis, and Spinner holding surface A two-fluid nozzle that sprays two fluids, water and air, onto the upper surface of a wafer held in place, and the two-fluid nozzle Spinner holding surface A nozzle moving means for moving in a direction parallel to the wafer; a moving distance setting unit for setting the moving distance of the two-fluid nozzle by the nozzle moving means; a speed setting unit for setting the speed at which the two-fluid nozzle moves at the distance set by the moving distance setting unit; and a mechanism for stopping the two-fluid nozzle at a position where the two fluids come into contact with the outer upper surface and outer side surface of the wafer. Stop The control unit comprises a stop time setting unit for setting the time, The wafer has a protective tape attached to its underside, and the control unit includes a tape thickness setting unit for setting the thickness of the protective tape, and a data table relating the thickness of the protective tape to the stop time, and the stop time setting unit sets the stop time by referring to the data table with the thickness of the protective tape set in the tape thickness setting unit. The control unit controls the rotation of the spinner table, positioning the two-fluid nozzle above the center of the upper surface of the wafer, ejecting the two fluids from the two-fluid nozzle, moving the two-fluid nozzle toward the outer circumference of the wafer by a distance set by the movement distance setting unit at a speed set by the speed setting unit, and applying the two fluids ejected from the two-fluid nozzle to the outer upper surface and outer side surface of the wafer for the duration of the stop time. Furthermore, the present invention relates to a wafer cleaning method using the wafer cleaning apparatus described above, comprising: a tape thickness setting step of setting the thickness of the protective tape in the tape thickness setting unit; a stop time setting step of setting the stop time by referring to the data table using the thickness of the protective tape set in the tape thickness setting unit; and a preparation step of rotating the spinner table, which holds the wafer on the spinner holding surface, around the center of the spinner holding surface as an axis, and positioning the two-fluid nozzle so that the two fluids ejected from the two-fluid nozzle land on the center of the spinner holding surface. The device comprises: an upper surface cleaning step in which two fluids are ejected from the two-fluid nozzle and the two-fluid nozzle is moved at a predetermined speed in the radial direction of the wafer to clean the upper surface of the wafer held on the spinner holding surface; and an outer surface cleaning step in which the two fluids ejected from the two-fluid nozzle, which is moving in the radial direction of the wafer, are moved to a position where they come into contact with the outer circumference of the wafer, and the two-fluid nozzle, which is applying the two fluids to the outer surface upper and outer surface sides of the wafer, is stopped for a stop time set in the stop time setting step to clean the outer surface upper and outer surface sides of the wafer.

[0010] Furthermore, the present invention relates to a processing apparatus for processing wafers, which includes the above-mentioned wafer cleaning apparatus, Chuck holding surface a chuck table that holds the wafer via the protective tape, and Chuck holding surface Processing means for processing a wafer held in, Chuck holding surface A wafer thickness measuring device that measures the thickness of only the wafer held in it, and Chuck holding surface A total thickness measuring device that measures the thickness of the protective tape held in place and the wafer, A first transport means for transporting a wafer to the chuck table, and a second transport means for transporting a wafer from the chuck table to the spinner table, The processing apparatus control unit comprises a protective tape thickness calculation unit which calculates the thickness of the protective tape by subtracting the value measured by the wafer thickness measuring unit from the value measured by the total thickness measuring unit, and a setting unit which sets the value calculated by the protective tape thickness calculation unit to the tape thickness setting unit. The second transport means is controlled to transport the wafer from the chuck table to the spinner table. During the stop time set by the control unit of the wafer cleaning apparatus The spinner table is Clean the upper and lower edges of the wafer. Furthermore, the present invention relates to a wafer processing method using the wafer processing apparatus described above, comprising: a chuck holding step in which the wafer is transported to a chuck table by the first transport means and the chuck table holds the wafer; a processing step in which the wafer held on the chuck table is processed; a wafer thickness measurement step in which the thickness of only the wafer held on the chuck table is measured with a wafer thickness measuring instrument; a total thickness measurement step in which the total thickness of the protective tape and the wafer held on the chuck table is measured with a total thickness measuring instrument; a tape thickness setting step in which the thickness of the protective tape is calculated by subtracting the value measured in the wafer thickness measurement step from the value measured in the total thickness measurement step and setting the calculated value in the tape thickness setting unit; a stop time setting step in which the stop time is set by referring to the data table with the thickness of the protective tape set in the tape thickness setting step; and the wafer is transported to the chuck table by the second transport means A wafer processing method comprising: a spinner holding step of transporting the wafer from a table to the spinner table and having the spinner table hold the wafer; a preparation step of rotating the spinner table, with the wafer held on the spinner holding surface, around the center of the spinner holding surface as an axis, and positioning the two-fluid nozzle so that the two fluids ejected from the two-fluid nozzle land on the center of the spinner holding surface; an upper surface cleaning step of cleaning the upper surface of the wafer held on the spinner holding surface by moving the two-fluid nozzle at a predetermined speed in the radial direction of the wafer while ejecting the two fluids from the two-fluid nozzle; and an outer edge cleaning step of cleaning the outer surface and outer edge of the wafer by moving the two-fluid nozzle, which is moving in the radial direction of the wafer, to a position where the two fluids ejected from the nozzle strike the outer circumference of the wafer, and stopping the two-fluid nozzle, which is applying the two fluids to the outer surface and outer edge of the wafer, for the stop time set in the stop time setting step. [Effects of the Invention]

[0012] According to the wafer cleaning method of the present invention using a cleaning device provided in the processing apparatus of the present invention, in the top surface cleaning step, the top surface of the wafer is uniformly cleaned over its entire surface by two fluids ejected from a two-fluid nozzle that moves radially along the wafer toward the rotating top surface of the wafer, and processing debris adhering to the top surface of the wafer is reliably removed. In particular, the stopping time of the two-fluid nozzle (the time during which the two-fluid nozzle remains stopped above the outer periphery of the wafer and continues to spray the two fluids toward the outer upper surface and outer side of the wafer) is set according to the thickness of the protective tape attached to the surface of the wafer (the surface opposite to the surface being processed), and the stopping time is set to be longer the thicker the protective tape, so that processing debris adhering to the outer side surface of the protective tape (adhesive layer) can be effectively removed.

[0013] In the outer periphery cleaning step, when the two-fluid nozzle moves to a position where the two-fluid ejected from the two-fluid nozzle hits the outer periphery of the wafer, the two-fluid nozzle is stopped at that position for a predetermined time, and the two-fluid is continuously ejected downward from this two-fluid nozzle toward the upper surface and the side surface of the outer periphery of the wafer. Therefore, the upper surface and the side surface of the outer periphery of the wafer are effectively cleaned by the two-fluid, and the processing debris adhering to the upper surface and the side surface of the outer periphery of the wafer is surely removed. Further, in this outer periphery cleaning step, the two-fluid nozzle does not reciprocate as in the conventional case, and the two-fluid is ejected vertically downward from the two-fluid nozzle. Therefore, on the upper surface of the spinner table, the two-fluid nozzle rebounds in the vertical direction, and an oblique force that tries to separate the wafer from the holding surface does not act on the outer peripheral edge of the wafer, and breakage such as cracking of the outer peripheral edge of the wafer is surely prevented. [[ID=II]]

Brief Description of the Drawings

[0014] [Figure 1] It is a perspective view showing a part of a wafer processing apparatus (polishing apparatus) according to the first invention broken away. [Figure 2] It is a perspective view showing a part of a wafer cleaning apparatus according to the second invention broken away. [Figure 3] It is a broken front view of a cleaning apparatus showing a preparation step in a wafer cleaning method according to the third invention. [Figure 4] It is a broken front view of a cleaning apparatus showing an upper surface cleaning step in a wafer cleaning method according to the third invention. [Figure 5] It is a broken front view of a cleaning apparatus showing an outer periphery cleaning step in a wafer cleaning method according to the third invention. <0OO0091> [Figure 6] [[ID=III]]It is a plan view showing the radial movement of a two-fluid injection nozzle with respect to a wafer in a wafer cleaning apparatus according to the third invention. [Figure 7] It is a time chart showing the time change of the movement of the two-fluid nozzle in a wafer cleaning method according to the third invention.

Embodiments for Carrying Out the Invention

[0015] <First Invention> The configuration of a polishing apparatus as one embodiment of the processing apparatus according to the first invention will be described below with reference to Figure 1. In the following description, the arrow directions shown in Figure 1 will be the X-axis direction (left and right direction), the Y-axis direction (front and back direction), and the Z-axis direction (up and down direction), respectively. First, the configuration of a polishing apparatus as one embodiment of the wafer processing apparatus according to the present invention will be described. In the following description, the arrow directions shown in Figure 1 will be the X-axis direction (left and right direction), the Y-axis direction (front and back direction), and the Z-axis direction (up and down direction), respectively.

[0016] [Configuration of the polishing device] The polishing apparatus 100 shown in Figure 1 is a device for polishing a disc-shaped wafer W, which is the object to be polished, and its main components include a chuck table 25 for holding the wafer W, a processing means (polishing mechanism) 70 for polishing the wafer W held on the chuck table 25, a wafer thickness measuring instrument 26 for measuring the thickness of the wafer W, a total thickness measuring instrument 27 for measuring the thickness (total thickness) of the wafer W and the protective tape T (see Figure 3) attached to its surface (bottom surface in Figure 1), a cleaning device 1 for cleaning the top surface (polished surface) of the wafer W, a transport unit 110 for transporting the wafer W, and a processing apparatus control unit 90.

[0017] Next, the configurations of the main components of the polishing apparatus 100—the chuck table 25, processing unit 70, wafer thickness measuring instrument 26, total thickness measuring instrument 27, cleaning device 1, transport unit 110, and processing apparatus control unit 90—will be described.

[0018] (Chuck table) The chuck table 25 is a disc-shaped component, and a disc-shaped porous component 25A made of porous ceramic or the like is incorporated in its center. The upper surface of the porous component 25A constitutes a holding surface 25a that attracts and holds the disc-shaped wafer W.

[0019] The chuck table 25 is rotated at a predetermined speed around its vertical central axis by an electric motor 28 located below it. An encoder 29 is provided below the electric motor 28 to detect the rotation speed and direction of the electric motor 28.

[0020] Incidentally, as shown in Figure 1, the polishing apparatus 100 according to this embodiment is equipped with a rectangular box-shaped base 200 that is long in the Y-axis direction (front-to-back direction), and a rectangular block-shaped internal base 201 is housed inside this base 200. On this internal base 201, a workpiece horizontal movement mechanism 80 is provided for moving the wafer W, which is held by suction on the chuck table 25 and its holding surface 25a, along the Y-axis direction (front-to-back direction).

[0021] The horizontal movement mechanism 80 described above includes a block-shaped slider 81, which is slidable in the Y-axis direction along a pair of left and right guide rails 82 that are arranged parallel to each other along the Y-axis direction (front-to-back direction). Therefore, the chuck table 25 supported by the slider 81 and the electric motor 28 that rotates it are slidable together with the slider 81 along the Y-axis direction.

[0022] A rotatable ball screw shaft 83 extending in the Y-axis direction (front-to-back direction) is positioned between a pair of left and right guide rails 83 on the internal base 201. One end of this ball screw shaft 83 in the Y-axis direction (the left end in Figure 1) is connected to a reversible electric motor 84, which is the drive source. The other end of the ball screw shaft 83 in the Y-axis direction (the right end in Figure 1) is rotatably supported by a bearing 85 erected on the internal base 201. A nut member (not shown) protruding downward from the slider 81 is screwed onto the ball screw shaft 83.

[0023] Therefore, when the electric motor 84 rotates the ball screw shaft 83 in forward and reverse directions, a nut member (not shown) that screws onto the ball screw shaft 83 slides along the ball screw shaft 83 in the Y-axis direction (forward and backward direction) together with the slider 81. As a result, the chuck table 25 also moves integrally along the Y-axis direction together with the slider 81. Consequently, the wafer W, which is the workpiece to be polished and is held by suction on the holding surface 25a of the chuck table 25, also moves along the Y-axis direction.

[0024] (Processing means) The processing means (polishing mechanism) 70 for polishing the back surface (front surface in Figure 1) of the wafer W comprises a spindle 71 having a rotational central axis in the Z-axis direction, a spindle motor 72 for rotationally driving the spindle 71, a mount 73 connected to the lower end of the spindle 71, and a disc-shaped polishing pad 74 detachably attached to the lower surface of the mount 73.

[0025] Furthermore, in the polishing apparatus 100 according to this embodiment, as shown in Figure 1, a rectangular box-shaped column 210 is erected vertically on the +Y-axis end (rear end) of the upper surface of the base 200, and a lifting mechanism 75 is provided on the -Y-axis end face (front) of this column 210. This lifting mechanism 75 moves the processing means (polishing mechanism) 70 up and down in a direction perpendicular to the holding surface 25a of the chuck table 25 (Z-axis direction), and moves a rectangular plate-shaped lifting plate 76 up and down in the Z-axis direction along a pair of left and right guide rails 77 together with the processing means 70. Here, the pair of left and right guide rails 77 are arranged perpendicularly and parallel to each other on the front surface of the column 210.

[0026] A rotatable ball screw shaft 78 is erected vertically between a pair of left and right guide rails 77 along the Z-axis direction (up and down direction), and the upper end of the ball screw shaft 78 is connected to a reversible electric motor 79, which is the drive source. The lower end of the ball screw shaft 78 is rotatably supported by a bearing (not shown) on the column 210, and a nut member (not shown) that protrudes horizontally toward the rear (+Y-axis direction) from the back of the lifting plate 76 is screwed onto this ball screw shaft 78.

[0027] (Wafer thickness measuring instrument) The wafer thickness measuring instrument 26 measures the thickness of the wafer W optically and non-contact. It projects measuring light from above the wafer W toward the wafer W and measures the thickness of the wafer W during grinding by measuring the optical path difference between the upper surface reflected light and the lower surface reflected light reflected from the upper and lower surfaces of the wafer W, respectively. The measurement result is transmitted to the processing apparatus control unit 90.

[0028] (Total thickness measuring device) The total thickness measuring device 27 measures the thickness (total thickness) of the protective tape T and the wafer W, and is equipped with a contact element 27a that contacts the upper surface of the wafer W and a contact element 27b that contacts the upper surface of the chuck table 10. The measurement result from this total thickness measuring device 27 is transmitted to the processing apparatus control unit 90.

[0029] (Cleaning device) The cleaning apparatus 1 according to the present invention cleans a wafer W polished by a processing means 70 to remove polishing debris and other contaminants adhering to its polished surface (upper surface). It comprises a spinner table 10 that holds and rotates the polished wafer W, and a two-fluid nozzle 330 that sprays two fluids, water and air, toward the polished surface of the wafer W. Details of its configuration and operation will be described later.

[0030] (Transport unit) In the polishing apparatus 100 according to this embodiment, as shown in Figure 1, a cassette 111 for storing multiple wafers W before polishing and a cassette 112 for storing wafers W after polishing are arranged at the front end (-Y axis end) of the base 200. The transport unit 110 includes an loading / unloading means 114 for loading and unloading wafers W into and out of the cassette 111 and transporting the wafers W removed from the cassette 111 to the alignment table 113, a first transport means 115 for transporting the wafers W positioned on the alignment table 113 to the chuck table 25, and a second transport means 116 for removing the polished wafers W from the chuck table 25 and transporting them to the cleaning apparatus 1.

[0031] (Processing equipment control unit) The processing device control unit 90 includes a CPU (Central Processing Unit) that performs calculations according to a control program, and memory such as ROM (Read Only Memory) and RAM (Random Access Memory).

[0032] Here, the processing apparatus control unit 90 includes a protective tape thickness calculation unit that calculates the thickness of the protective tape T by subtracting the thickness of the wafer W measured by the wafer thickness measuring unit 26 from the total thickness of the protective tape T and the wafer W measured by the total thickness measuring unit 27, and a setting unit that sets the thickness of the protective tape T calculated by the protective tape thickness calculation unit to the tape thickness setting unit provided in the control unit 50 of the cleaning apparatus 1, which will be described later.

[0033] [Operation of polishing equipment] Next, we will explain the polishing process of wafer W using the polishing apparatus 100 configured as described above.

[0034] When polishing the wafer W, the wafer W is placed on the holding surface 25a of the chuck table 25 with the protective tape T facing downwards. Then, when the porous member 25A is evacuated by a suction source (not shown), negative pressure is generated in the porous member 25A, and the wafer W, which is placed on the upper surface (holding surface 25a) of the porous member 25A, is attracted and held on the holding surface 25a by the negative pressure.

[0035] From the above state, the horizontal movement mechanism 80 is driven to move the chuck table 25 in the +Y axis direction (rearward), positioning the wafer W held by the chuck table 25 below the polishing pad 74 of the processing means 70. That is, when the electric motor 84 is started and the ball screw shaft 83 rotates, a slider 81 to which a nut member (not shown) that screws onto the ball screw shaft 83 is attached slides along a pair of left and right guide rails 82 in the +Y axis direction together with the chuck table 25, etc., so that the wafer W held on the holding surface 25a of the chuck table 25 is positioned below the polishing pad 74 of the processing means 70.

[0036] Furthermore, the electric motor 28 is driven to rotate the chuck table 25 at a predetermined rotational speed (for example, 300 rpm). Simultaneously, the spindle motor 72 of the machining means 70 is started to rotate the polishing pad 74 at a predetermined speed (for example, 1000 rpm).

[0037] As described above, with the wafer W and polishing pad 74 rotating, the lifting mechanism 75 is driven to lower the polishing pad 74 in the -Z axis direction. That is, when the electric motor 79 is driven and the ball screw shaft 78 rotates, the lifting plate 76, which is equipped with a nut member (not shown) that screws onto the ball screw shaft 78, descends in the -Z axis direction together with the polishing means. At this point, the lower surface (polishing surface) of the polishing pad 74 comes into contact with the upper surface (back surface) of the wafer W. At this time, slurry is supplied from a slurry supply source (not shown) to the contact surface between the polishing pad 74 and the wafer W. As a result, the chemical action of the slurry and the mechanical action of the polishing pad 74 combine to polish the upper surface of the wafer W.

[0038] As described above, when the wafer W is polished by the polishing pad 74 in the processing means 70, the wafer W is transported from the chuck table 25 to the cleaning device 1 by the second transport means 116, and the upper surface (polished surface) of the wafer W is cleaned by the cleaning device 1.

[0039] Herein, the second invention, the wafer cleaning apparatus 1 for wafer W, will be described below. <Second Invention> First, the configuration of the cleaning device 1 will be described below based on Figures 2 and 3.

[0040] [Configuration of the cleaning device] The cleaning apparatus 1 shown in Figure 1 is a device for cleaning a disc-shaped wafer W (see Figure 3) whose back surface (top surface in Figure 3) has been polished by the polishing apparatus 100 shown in Figure 1 in the preceding polishing process. The cleaning apparatus mainly comprises a rotatable spinner table 10 for holding the wafer W, a rotating means 20 for rotating the spinner table 10 at a predetermined speed around its vertical central axis, a two-fluid nozzle 30 positioned above the spinner table 10 (wafer W), a nozzle moving means 40 for moving the two-fluid nozzle 30 above the wafer W in the radial direction of the wafer W (left-right direction in Figure 2), and a control unit 50 for controlling the operation of the nozzle moving means 40 and the like. As shown in Figure 2, the spinner table 10, the two-fluid nozzle 30, and part of the nozzle moving means 40 are housed in a bottomed polygonal cylindrical cover 60 that opens at the top.

[0041] Here, the wafer W shown in Figure 3 is a thin, disc-shaped component made of a single-crystal silicon matrix, and multiple devices (not shown) are formed on the downward-facing surface in the state shown in Figure 3. These devices are protected by a protective tape T (see Figure 3) attached to the surface of the wafer W. The wafer W is held in place by suction on its surface (bottom surface in Figure 3) via the protective tape T to the spinner table 10, and its back surface (top surface in Figure 3) is polished by the polishing apparatus 100 shown in Figure 1 in the polishing process, which is a step before the cleaning process.

[0042] Next, the configurations of the main components of the cleaning device 1, namely the spinner table 10, the rotating means 20, the two-fluid nozzle 30, the nozzle moving means 40, and the control unit 50, will be described.

[0043] (Spinner Table) The spinner table 10 is a disc-shaped member, and a disc-shaped porous member 11 made of porous ceramic or the like is incorporated into a circular recess 10a (see Figure 3) formed in the center of the spinner table 10. The upper surface of the porous member 11 constitutes a holding surface 11a that attracts and holds the wafer W via a protective tape T.

[0044] Here, as shown in Figure 3, a suction source 12 such as a vacuum pump and an air supply source 13 such as an air compressor are connected to the porous member 11. Specifically, a communication passage 2 is formed vertically at the axial center of the spinner table 10, and from this communication passage 2, multiple (only two are shown in Figure 3) horizontal communication passages 3 extend radially outward. From the outer end of each communication passage 3, a communication passage 4 extends vertically upward, and each communication passage 4 opens to the lower surface of the porous member 11.

[0045] Furthermore, connecting passages 5 are formed vertically at the center of each axis of the rotating shaft 23 and the rotary joint 22, and the upper end of these connecting passages 5 is in communication with connecting passage 2. The lower end of connecting passage 5 is connected to a connecting passage 6 that is formed horizontally along the radial direction of the rotary joint 22, and piping 7 is connected to the connecting passage 6.

[0046] Two branch pipes, 8 and 9, branch off from the above-mentioned piping 7. One branch pipe 8 is connected to the suction source 12 via a variable orifice 14 for flow rate adjustment and a solenoid valve 15. The other branch pipe 9 is connected to the air supply source 13 via a variable orifice 16 for flow rate adjustment and a solenoid valve 17. The solenoid valves 15 and 17 are electrically connected to the control unit 50, and their opening and closing operations are controlled by the control unit 50. A pressure gauge 18 is connected between the two branch pipes 8 and 9 of piping 7.

[0047] (Rotational means) The rotating mechanism 20 includes an electric motor 21 as a drive source for rotating the spinner table 10 around its vertical central axis at a predetermined speed (800 rpm in this embodiment). A rotating shaft (motor shaft) 23 extending vertically upward from the electric motor 21 via a rotary joint 22 passes through the bottom of the case 60 and faces into the case 60 (see Figure 2), and the spinner table 10 is horizontally mounted on its upper end.

[0048] Furthermore, an encoder 24 is provided at the bottom of the electric motor 21 to detect the rotation speed, rotation angle, and rotation direction of the electric motor 21, and this encoder 24 and the electric motor 21 are electrically connected to the control unit 50. Here, the detection signal from the encoder 24 is transmitted to the control unit 50, and the control unit 50 receives the detection signal from the encoder 24 and controls the drive of the electric motor 21.

[0049] (Two-fluid nozzle) Above the wafer W held on the spinner table 10, a two-fluid nozzle 30 is provided that sprays two fluids, water and air, toward the upper surface (back surface) of the wafer W. A water source 31, such as a water pump, and an air source 32, such as an air compressor, are connected to this two-fluid nozzle 30. These water source 31 and air source 32 are electrically connected to a control unit 50, and their operation is controlled by the control unit 50.

[0050] (Nozzle moving mechanism) The nozzle moving means 40 is a mechanism that moves the two-fluid nozzle 30 horizontally (parallel to the holding surface 11a of the spinner table 10) above the wafer W along the radial direction of the wafer W (left-right direction in Figure 3), and is equipped with an electric motor 41 which is a rotation drive source. An output shaft (motor shaft) 42 extending vertically upward from this electric motor 41 passes through the bottom of the case 60 shown in Figure 2 and faces into the case 60, and one end in the longitudinal direction of a horizontally positioned swivel arm 43 is attached to its upper end. The other end (tip) in the longitudinal direction of the swivel arm 43 is attached to the two-fluid nozzle 30 so that its nozzle faces vertically downward.

[0051] Furthermore, an encoder 44 is provided at the bottom of the electric motor 41 to detect the rotation speed, rotation angle, and rotation direction of the electric motor 41, and this encoder 44 and the electric motor 41 are electrically connected to the control unit 50. Here, the detection signal from the encoder 44 is transmitted to the control unit 50, and the control unit 50 receives the detection signal from the encoder 44 and controls the drive of the electric motor 41.

[0052] In the nozzle moving means 40 configured as described above, when the electric motor 41 is activated and the output shaft (motor shaft) 42 rotates by a predetermined angle, the swivel arm 43 attached to the upper end of the output shaft 42 rotates horizontally as shown by the arrow in Figure 6, and the two-fluid nozzle 30 attached to the tip of the swivel arm 43 rotates horizontally above the wafer W, moving radially along the wafer W, for example, from the center O of the wafer W to the outer circumference.

[0053] (Control Unit) The control unit 50 is configured to include a CPU that performs calculations according to a control program, and memory such as ROM and RAM, similar to the processing device control unit provided in the polishing device 100 shown in Figure 1.

[0054] Here, the control unit 50 includes a movement distance setting unit 51 that sets the movement distance by which the two-fluid nozzle 30 is moved by the nozzle moving means 40, a speed setting unit 52 that sets the speed at which the two-fluid nozzle 30 is moved by the distance set by the movement distance setting unit 51, and a stop time setting unit 53 that sets the time for which the two-fluid nozzle 30 is stopped at a position where the two fluids strike the upper surface and outer side surface of the outer edge of the wafer W. In addition, the control unit 50 includes a tape thickness setting unit that sets the thickness of the protective tape T, and a data table that associates the thickness of the protective tape T with the stop time of the two-fluid nozzle 30. Here, the stop time of the two-fluid nozzle 30 is the time for which the movement of the wafer W is stopped when the landing point of the two fluids ejected from the two-fluid nozzle 30, which moves radially in the wafer W as described later, reaches the outer edge of the wafer W.

[0055] <Third Invention> Next, a method for cleaning wafers W using the cleaning apparatus 1 configured as described above will be explained.

[0056] [Wafer cleaning method] The third invention relates to a method for cleaning a wafer W, which involves sequentially following 1) a preparation step, 2) a top surface cleaning step, and 3) an outer edge cleaning step, as described below.

[0057] 1) Preparation process: The preparation step, as shown in Figure 3, involves rotating the spinner table 10, which holds the wafer W on the holding surface 11a, at a predetermined speed (800 rpm in this embodiment) with the center of the holding surface 11a as its axis, and positioning the two-fluid nozzle 30 so that its nozzle opens above the center O of the wafer W, so that the two fluids ejected from the two-fluid nozzle 30 land on the center O of the wafer W.

[0058] First, in order to hold the wafer W on the holding surface 11a of the spinner table 10, the wafer W is placed on the holding surface (upper surface of the porous member 11) 11a of the spinner table 10 with the protective tape T facing downwards. Then, the control unit 50 opens the electromagnetic valve 15. As a result, the air inside the porous member 11 is drawn to the suction source 12 through the communication passages 4, 3, 2, 6 and the piping 7 and branch pipe 8 in sequence, creating negative pressure in the porous member 11. The wafer W, along with the protective tape T, is attracted and held on the holding surface 11a of the spinner table 10 by this negative pressure. At this time, the electromagnetic valve 17 is closed.

[0059] Next, the control unit 50 starts the electric motor 21 of the rotating means 20 to rotate the spinner table 10 and the wafer W held therein at a predetermined rotational speed (800 rpm) in the direction of the arrow in Figure 3 (counterclockwise). Also, in this preparation step, as shown in Figure 3, the control unit 50 is kept in standby position where the center of the two-fluid nozzle 30 coincides with the center O of the wafer W (the position where the two fluids sprayed from the two-fluid nozzle 30 land on the center O of the wafer W).

[0060] 2) Top surface cleaning process: The top surface cleaning process, as shown in Figure 4, is a process in which the top surface of the wafer W is cleaned with two fluids by spraying two fluids from a two-fluid nozzle 30 toward the top surface of the wafer W, while moving the two-fluid nozzle 30 at a predetermined speed in the radial direction of the wafer W (in the direction of the arrow in Figure 4) using a nozzle moving means 40. Specifically, when the electric motor 41 of the nozzle moving means 40 is activated and the output shaft (motor shaft) 42 rotates at a predetermined speed by a predetermined angle in the direction of the arrow in Figure 6 (counterclockwise), the swivel arm 43 and the two-fluid nozzle 30 attached to its tip rotate horizontally around the output shaft 42. As a result, the two-fluid nozzle 30 moves in an arc from a position above the center O of the wafer W toward the outer circumference of the wafer W.

[0061] Figure 7 shows the time evolution of the movement of the two-fluid nozzle 30 in a time chart. In Figure 7, the horizontal axis represents time t, and the vertical axis represents the distance r traveled by the two-fluid nozzle 30. The radius of the wafer W is denoted as r0.

[0062] In this embodiment, a wafer W with a diameter of φ150 mm (radius r0 = 150 mm) is used, and the wafer W rotates at a predetermined rotational speed (800 rpm) in the direction of the arrow in Figure 6 (counterclockwise). Therefore, the movement distance setting unit 51 of the control unit 50 sets the movement distance of the two-fluid nozzle 30 to 150 mm.

[0063] Incidentally, the two-fluid nozzle 30 slows down from a position where the two fluids ejected from the nozzle 30 are 5 mm in front of the outer edge of the wafer W (the position where the travel distance r of the two-fluid nozzle 30 is r1 = 145 mm). Specifically, the two-fluid nozzle 30 moves at a constant speed (slope of line A = dr / dt) along the straight line A shown in Figure 7 radially (to the right in Figure 4) from the center O of the wafer W until the travel distance r from the center O of the wafer W reaches r1 = 145 mm. When the travel distance r of the two-fluid nozzle 30 reaches r1 (= 145 mm), the speed of the two-fluid nozzle 30 is reduced, and the two-fluid nozzle 30 moves at a constant speed (slope of line B) along the straight line B shown in Figure 7 until it reaches the outer edge of the wafer W (r = r0).

[0064] Specifically, in this embodiment, the movement speed setting unit 52 of the control unit 50 sets the movement speed A of the two-fluid nozzle 30 to 26.2 mm / sec until the landing point of the two fluids ejected from the two-fluid nozzle 30 reaches a position 5 mm in front of the outer edge of the wafer W (r=r1). Thereafter, until the two fluids ejected from the two-fluid nozzle 30 reach the outer edge of the wafer W (while the movement distance r is within the range of (r0-r1)), the movement speed B of the two-fluid nozzle 30 is reduced to 1 / 7 and set to 3.7 mm / sec.

[0065] Therefore, the time t1 for the two-fluid nozzle 30 to travel a distance of r1 = 145 mm from the center O of the wafer W to a position 5 mm before the outer edge (r = r1) is 145 / 26.2 = 5.53 seconds, and the time Δt1 = (t2 - t1) for traveling the distance from 5 mm before the outer edge of the wafer W to the outer edge (r0 - r1) is 5 / 3.7 = 1.35 seconds. Time t2 is the time it takes for the two fluids ejected from the two-fluid nozzle 30 to reach the outer edge of the wafer W (see Figure 7). The diameter of the point where the two fluids ejected from the two-fluid nozzle 30 land on the wafer W is φ2 mm.

[0066] Here, the landing point of the two fluids ejected from the two-fluid nozzle 30 is positioned so that its center is slightly inward from the outer edge of the wafer W. This allows for cleaning of the notch portion indicating the crystal orientation, which is formed to a maximum depth of 1 mm in the direction from the outer edge of the wafer W toward the center O. In this embodiment, the speed is set to change in two stages from moving speed A to moving speed B, but the speed of the two-fluid nozzle 30 may be set to gradually decrease as it moves toward the outer edge of the wafer W.

[0067] As described above, by spraying the two fluids from the two-fluid nozzle 30 toward the upper surface of the wafer W rotating at a predetermined speed, and moving the two-fluid nozzle 30 radially from the center O of the wafer W to the outer edge, the upper surface of the wafer W is uniformly cleaned over its entire surface, and foreign matter such as polishing debris adhering to the upper surface of the wafer W is reliably removed.

[0068] 3) Outer surface cleaning process: The outer perimeter cleaning process involves cleaning the outer perimeter of the wafer W by stopping the two-fluid nozzle 30 for a predetermined time (time Δt2 (=t3-t2) shown in Figure 7) as shown in Figure 5, when the two-fluid nozzle 30 moves to a position (r=r0) where the two fluids ejected from the nozzle 30 reach the outer perimeter of the wafer W (time t=t3 shown in Figure 7), as shown in Figure 5. This maintains the landing point of the two fluids ejected from the two-fluid nozzle 30 on the outer perimeter (outer perimeter top surface and outer perimeter side surface) of the wafer W. The predetermined time Δt2 for stopping the two-fluid nozzle 30 above the outer perimeter (r=r0) of the wafer W is set by the stop time setting unit 53 of the control unit 50. Specifically, the control unit 50 sets the stop time Δt2 of the two-fluid nozzle 30 by referring to a data table using the thickness of the protective tape T set in the tape thickness setting unit. This stop time Δt2 is set according to the thickness of the protective tape T as shown in Table 1.

[0069] [Table 1]

[0070] In other words, as shown in Table 1, when the thickness of the protective tape T is 150 μm, 200 μm, and 260 μm, the stopping time Δt2 is set to 1 sec, 2 sec, and 3 sec, respectively. Here, the thickness of the protective tape T is the sum of the thickness of the base material and the adhesive layer of the protective tape T. The thickness of the base material is constant, and the thickness of the adhesive layer increases or decreases according to the thickness of the protective tape T. Therefore, as the thickness of the protective tape T increases, the thickness of the adhesive layer also increases. As a result, the thickness of the adhesive layer of a thick protective tape T becomes thicker than that of a thin protective tape T, and polishing debris and the like tend to adhere to the adhesive layer of a thick protective tape T. Therefore, in this embodiment, the stopping time (spraying time of the two fluids) Δt2 (see Figure 7) of the two-fluid nozzle 30 is set to be longer as the thickness of the protective tape T increases, in order to effectively remove polishing debris and the like that adhering to the adhesive layer. The moving speeds A and B of the two-fluid nozzle 30 are set independently of the thickness of the protective tape T.

[0071] As described above, in this outer edge cleaning process, when the two-fluid nozzle 30 moves to a position where the two fluids ejected from the nozzle 30 reach the outer edge of the wafer W (t=t2), the nozzle 30 is stopped at that position for a predetermined time Δt2 (3 seconds in this embodiment), and the two fluids are continuously ejected downward from the nozzle 30 toward the outer edge (outer upper surface and outer side surface) of the wafer W. As a result, the outer upper surface and outer side surface of the wafer W are effectively cleaned by the two fluids, and foreign matter such as polishing debris adhering to the outer upper surface and outer side surface of the wafer W is reliably removed.

[0072] Furthermore, in this outer edge cleaning process, the two-fluid nozzle 30 does not reciprocate as in the conventional method, but rather the two fluids are sprayed vertically downward while the nozzle 30 is stationary. As a result, the two fluids bounce vertically off the upper surface of the spinner table 10, and no oblique force acts on the outer edge of the wafer W that would pull the wafer W away from the holding surface 11a. Therefore, damage such as cracking of the outer edge of the wafer W is reliably prevented.

[0073] In this embodiment, the operation of moving the two-fluid nozzle 30 radially and stopping it at the outer edge of the wafer W for a predetermined time was performed only once, but this operation may be repeated multiple times.

[0074] Incidentally, once the top surface of the wafer W has been cleaned through the above preparation process, top surface cleaning process, and outer periphery cleaning process, the control unit 50 closes one of the electromagnetic valves 15 shown in Figure 5 and opens the other electromagnetic valve 17. Then, compressed air is supplied from the air supply source 13 to the porous member 11 sequentially through the branch pipe 9, piping 7, and connecting passages 6, 5, 2, 3, and 4. As this compressed air is ejected from the holding surface 11a of the porous member 11, the suction force on the wafer W disappears, and the wafer W can be easily removed from the holding surface 11a together with the protective tape T.

[0075] Then, the wafer is removed from the spinner table 51 by the loading / unloading means 114 shown in Figure 1 and stored in the cassette 112, completing the series of polishing and cleaning processes for the wafer 100.

[0076] Although the polishing apparatus was described above as an example of a wafer processing apparatus according to the present invention, the present invention also applies to any other processing apparatus other than a polishing apparatus. Furthermore, the wafer cleaning apparatus and cleaning method according to the present invention can be applied not only to cleaning wafers after polishing, but also to cleaning wafers after grinding or cutting.

[0077] Furthermore, the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the technical idea described in the claims, specification, and drawings. [Explanation of Symbols]

[0078] 1: Washing device, 2-6: Connecting passages, 7: Piping, 8,9: Branch pipes, 10: Spinner table, 11: Porous member, 11a: Holding surface, 12: Suction source, 13: Air supply source, 14: Variable orifice, 15: Solenoid valve, 16: Variable orifice, 17: Electromagnetic valve, 18: Pressure gauge, 20: Rotating mechanism, 21: Electric motor, 22: Rotary joint, 23: Rotating shaft, 24: Encoder, 25: Chuck table, 25A: Porous member, 25a: Holding surface, 26: Wafer thickness measuring instrument, 27: Total thickness measuring instrument, 27a, 27b: Contact element, 28: Electric motor, 29: Encoder, 30: Two-fluid nozzle, 31: Water source, 32: Air source, 40: Nozzle moving mechanism, 41: Electric motor, 42: Output shaft, 43: Swivel arm, 44: Encoder, 50: Control unit, 51: Distance setting unit, 52: Speed ​​setting unit, 53: Stop time setting unit, 60: Case, 70: Machining means, 71: Spindle, 72: Spindle motor, 73: Mount, 74: Polishing pad, 75: Lifting mechanism, 76: Lifting plate, 77: Guide rail, 78: Ball screw shaft, 79: Electric motor, 80: Horizontal movement mechanism, 81: Slider, 82: Guide rail, 83: Ball screw shaft, 84: Electric motor, 85: Bearing 90: Processing device control unit, 100: Polishing device, 110: Conveying unit, 111,112: Cassette, 113: Alignment table, 114: Loading / unloading means, 115: First conveying means, 116: Second conveying means, 200: Base, 201: Internal base, 210: Column, O: center of the wafer, r: travel distance of the two-fluid nozzle, r0: radius of the wafer. T: protective tape, t: time, Δt1: travel time of the two-fluid nozzle. Δt2: Stop time of the two-fluid nozzle, r0: Radius of the wafer, W: Wafer

Claims

1. A wafer cleaning apparatus for cleaning wafers, A spinner table that holds the wafer on the spinner holding surface, A rotating means for rotating the spinner table around the center of the spinner holding surface, A two-fluid nozzle that sprays two fluids, water and air, onto the upper surface of the wafer held on the spinner holding surface, A nozzle moving means for moving the two-fluid nozzle in a direction parallel to the spinner holding surface, A control unit comprising: a movement distance setting unit for setting the movement distance for moving the two-fluid nozzle with the nozzle moving means; a speed setting unit for setting the speed at which the two-fluid nozzle moves over the distance set by the movement distance setting unit; and a stop time setting unit for setting the stop time for stopping the two-fluid nozzle at a position where the two fluids come into contact with the outer upper surface and outer side surface of the wafer. Equipped with, The wafer has protective tape attached to its underside. The control unit is A tape thickness setting unit for setting the thickness of the protective tape, The system includes a data table that associates the thickness of the protective tape with the stop time, The stop time setting unit sets the stop time by referring to the data table with respect to the thickness of the protective tape set in the tape thickness setting unit. The control unit is A wafer cleaning apparatus that controls the following: rotating the spinner table; positioning the two-fluid nozzle above the center of the upper surface of the wafer; ejecting two fluids from the two-fluid nozzle; moving the two-fluid nozzle toward the outer circumference of the wafer by a distance set by the movement distance setting unit at a speed set by the speed setting unit; and applying the two fluids ejected from the two-fluid nozzle to the outer upper surface and outer side surface of the wafer for the duration of the stop time.

2. A method for cleaning a wafer using the wafer cleaning apparatus described in Claim 1, A tape thickness setting step in which the thickness of the protective tape is set in the tape thickness setting section, A stop time setting step involves setting the stop time by referring to the data table using the thickness of the protective tape set in the tape thickness setting unit, A preparatory step of rotating the spinner table, which holds the wafer on the spinner holding surface, around the center of the spinner holding surface as an axis, and positioning the two-fluid nozzle so that the two fluids ejected from the nozzle land on the center of the spinner holding surface, A top surface cleaning step in which two fluids are ejected from the two-fluid nozzle, and the two-fluid nozzle is moved at a predetermined speed in the radial direction of the wafer, thereby cleaning the top surface of the wafer held on the spinner holding surface, An outer edge cleaning step involves moving the two-fluid nozzle, which moves radially across the wafer, to a position where the two fluids ejected from the nozzle strike the outer edge of the wafer, and stopping the two-fluid nozzle, which is applying the two fluids to the outer edge top and outer edge sides of the wafer, for the stop time set in the stop time setting step, thereby cleaning the outer edge top and outer edge sides of the wafer. A wafer cleaning method comprising [a specific feature / feature].

3. A processing apparatus for processing wafers, comprising the wafer cleaning apparatus described in claim 1, A chuck table that holds the wafer via the protective tape on the chuck holding surface, A processing means for processing a wafer held on the chuck holding surface, A wafer thickness measuring device that measures the thickness of only the wafer held on the chuck holding surface, A total thickness measuring device for measuring the thickness of the protective tape and wafer held on the chuck holding surface, The chuck table includes a first transport means for transporting wafers, A second transport means for transporting wafers from the chuck table to the spinner table, Processing equipment control unit, Equipped with, The processing apparatus control unit is: A protective tape thickness calculation unit calculates the thickness of the protective tape by subtracting the value measured by the wafer thickness measuring instrument from the value measured by the total thickness measuring instrument, A setting unit sets the value calculated by the protective tape thickness calculation unit to the tape thickness setting unit, Equipped with, A wafer processing apparatus that controls the second transport means to transport a wafer from the chuck table to the spinner table, and cleans the upper outer and outer side surfaces of the wafer held on the spinner table for a stop time set by the control unit of the wafer cleaning apparatus.

4. A wafer processing method using the wafer processing apparatus described in Claim 3, the method comprising processing a wafer, A chuck holding step in which the wafer is transported to a chuck table by the first transport means and the chuck table holds the wafer, A processing step for processing a wafer held on the chuck table, A wafer thickness measurement step in which the thickness of only the wafer held on the chuck table is measured using the wafer thickness measuring instrument, A total thickness measurement step in which the total thickness of the protective tape and the wafer held on the chuck table is measured with the total thickness measuring instrument, A tape thickness setting step involves subtracting the value measured in the wafer thickness measurement step from the value measured in the total thickness measurement step to calculate the thickness of the protective tape, and setting the calculated value in the tape thickness setting unit. A stop time setting step, in which the stop time is set by referring to the data table with the thickness of the protective tape set by the tape thickness setting step, A spinner holding step in which the wafer is transported from the chuck table to the spinner table by the second transport means and the spinner table holds the wafer, A preparatory step of rotating the spinner table, which holds the wafer on the spinner holding surface, around the center of the spinner holding surface as an axis, and positioning the two-fluid nozzle so that the two fluids ejected from the nozzle land on the center of the spinner holding surface, A top surface cleaning step in which two fluids are ejected from the two-fluid nozzle, and the two-fluid nozzle is moved at a predetermined speed in the radial direction of the wafer, thereby cleaning the top surface of the wafer held on the spinner holding surface, An outer edge cleaning step is performed by moving the two-fluid nozzle, which moves radially across the wafer, to a position where the two fluids ejected from the nozzle strike the outer edge of the wafer, and by stopping the two-fluid nozzle, which is applying the two fluids to the outer edge top surface and outer edge side surface of the wafer, for the stop time set in the stop time setting step, thereby cleaning the outer edge top surface and outer edge side surface of the wafer. A wafer processing method comprising [a specific feature].

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