JP2005203661A - Method and apparatus for measuring thin plate material - Google Patents

Abstract

Disclosed is a measuring apparatus and method capable of suppressing a variation in the center position in a spindle holding a thin plate material and performing highly accurate measurement.
After the wafer 5 is brought into contact with a first holding claw 14b and the thickness direction is regulated, the wafer 5 is brought into contact with the first holding claw 14b in the direction in which the first holding claw 14b is located. It is moved to contact the second holding claw 14a to regulate the center position of the wafer 5, and in a state where it is brought into contact with the second holding claw 14a, the third holding claw 14a is further opposed to the second holding claw 14a. The holding claw 11 b is brought into contact with the wafer 5 to hold the wafer 5, and the measurement sensor 9 is moved in the radial direction of the wafer 5 while rotating the held wafer 5 to measure the displacement of the wafer 5 surface.
[Selection] Figure 1

Description

  The present invention relates to a measuring method and a measuring apparatus for a thin plate material such as a semiconductor manufacturing wafer and a magnetic disk substrate.

  In a conventional apparatus for measuring thickness unevenness / warpage of a thin plate material such as a wafer (hereinafter referred to as a flatness measuring device), the measurement is performed by holding the thin plate material horizontally or vertically.

  FIG. 5 is a schematic configuration diagram of a flatness measuring apparatus that performs measurement while holding a conventional thin plate material vertically.

  In FIG. 5, the conventional flatness measuring apparatus includes a wafer holding stage 2 and a sensor moving stage 3 on a gantry 1.

  The wafer holding stage 2 includes a direct drive motor 4 and an annular spindle 6 that holds the wafer 5 on the inner periphery. The spindle 6 is rotationally driven by the direct drive motor 4 in the XY axis plane.

  The sensor moving stage 3 includes a motor 7, a ball screw 8 rotated by the motor 7, and a wafer flatness measuring sensor 9 which is an optical displacement meter, and the wafer flatness measuring sensor 9 is rotated by rotating the motor 7. The flatness of the surface of the wafer 5 attached to the spindle 6 was measured by moving in the X-axis direction. In FIG. 5, the wafer flatness measuring sensor 9 is shown only on one side, but the wafer flatness measuring sensor 9 is provided on both sides of the wafer 5.

  FIG. 6 is a schematic configuration diagram showing a spindle 6 that holds the wafer 5 and a transfer unit that supplies the wafer 5 to the spindle 6.

  In FIG. 6, a plurality of holding claws 11 a and 11 b are attached to the surface of the spindle 6 facing the transfer arm 10 at substantially equal intervals along the inner peripheral edge. The front ends of the holding claws 11a and 11b protrude in the center direction from the inner peripheral surface of the spindle 6. The front end surface has a thickness direction regulation and a center position regulation of a wafer 5 having a diameter of 300 mm and a thickness of 0.775 mm. For example, a V-shaped groove is formed to hold the outer peripheral edge while performing simultaneously. As shown in FIG. 7, the wafer 5 is held by contact between the sag portion 13 near the outer periphery of the wafer 5 and the groove surfaces of the holding claws 11a and 11b. The two holding claws 11 a are fixed, and the one holding claw 11 b is movable in the radial direction of the spindle 6.

  The tip of the transfer arm 10 is formed by a grip portion having a plurality of grip claws 12, is slidable in the radial direction of the wafer 5, and is biased toward the center by an elastic member such as a spring. The tip surface of the gripping claw 12 is formed with, for example, a V-shaped groove similarly to the tip surfaces of the holding claws 11a and 11b, and the wafer 5 is gripped with the sag portion 13 similarly to the holding claws 11a and 11b. The nail 12 is gripped by contact with the groove surface.

Using the holding claws 11a and 11b and the gripping claws 12 having the above-described configuration, the wafer 5 is transferred between the transfer arm 10 and the spindle 6 (see, for example, Patent Document 1).
JP 2003-273187 A

  In the conventional method as described above, the wafer thickness direction adjustment and the center position adjustment are performed by the same holding claw, and the sagging portion of the wafer that contacts the tip surface of the holding claw is the outer diameter of the wafer. Since the shape accuracy is poor and the variation is large compared to the accuracy, when the wafer is held in the sag portion, there is a problem that the variation occurs at the center position of the held wafer and the accuracy of the measurement data is deteriorated.

  In addition, there is a possibility that the tip surface of the holding claw may be deformed due to friction with the wafer, and if the shape of the portion of the holding claw tip surface that contacts the wafer is deformed, the center position of the held wafer will vary, There was a problem that the accuracy of the measurement data deteriorated.

  In order to solve the above-mentioned problems, the present invention provides a method in which a thin plate material is brought into contact with a first holding claw and the thickness direction is regulated, and then the thin plate material is brought into contact with the first holding claw in the state where The holding claw is moved in a certain direction and brought into contact with the second holding claw to regulate the center position of the thin plate material, and is further opposed to the second holding claw in a state of being in contact with the second holding claw. A third holding claw in a position to contact the thin plate material to hold the thin plate material, and while rotating the held thin plate material, move the measurement sensor in the radial direction of the thin plate material, and By measuring the displacement of the surface, the variation in the center position of the wafer in the spindle can be reduced to half or less, so that highly accurate measurement can be performed.

  According to the present invention, the position adjustment in the thickness direction of the wafer in the spindle is performed by the first holding claw, and the position adjustment of the center of the wafer is performed by the second holding claw. It is possible to perform the measurement at the outer diameter portion of the wafer with high accuracy, and the variation in the center position of the wafer within the spindle can be reduced to half or less, so that highly accurate measurement can be performed.

  Furthermore, by separating the holding claw that adjusts the position of the wafer in the thickness direction and the holding claw that controls the center position of the wafer, the variation in the center position of the held wafer due to wear over time is halved compared to the conventional case. It becomes possible to make it below, and it becomes possible to make the frequency | count of replacement | exchange operation | work of a holding nail less than half of the past.

  An embodiment of the present invention will be described with reference to FIGS.

  The flatness measuring apparatus according to the embodiment of the present invention uses the same apparatus as the conventional flatness measuring apparatus shown in FIG. 5, but the configuration of the holding portion of the wafer 5 provided on the inner peripheral edge of the spindle 6 is the same. Are different.

  FIG. 1 is a schematic configuration diagram of a holding unit according to an embodiment of the present invention.

  In FIG. 1, holding claws 11 b, 14 a, 14 b are provided along the inner peripheral edge of the spindle 6 from the inner peripheral surface of the spindle 6 in the center direction, and the holding claws 11 b, 14 b are arranged in the radial direction of the spindle 6. It is designed to move. Each of the holding claws 11b and 14b can be rotated in the inner circumferential direction of the spindle 6 by the rotation shaft 15, and is urged toward the center from the inner circumferential surface of the spindle 6 by an elastic member, for example, a spring 16. The stopper 17 is configured not to protrude toward the center direction beyond a predetermined distance.

  FIG. 2 is a diagram showing a cross-sectional shape of the holding claw 14a. As shown in FIG. 2A, the tip shape of the holding claw 14a has a surface perpendicular to the measurement surface of the wafer 5, and the wafer 5 is held by the tip surface of the holding claw 14a. The tip of the holding claw 14a may be shaped as shown in FIG. 2 (b) as long as it can be prevented from coming into contact with the measurement surface of the wafer 5.

  FIG. 3 is a diagram illustrating a cross-sectional shape of the holding claws 11b and 14b. As shown in FIG. 3 (a), the tips of the holding claws 11b and 14b have V-shaped grooves formed of contact surfaces 18a and 18b having a predetermined angle. The sag portion 13 near the outer periphery and the V-shaped groove surfaces of the holding claws 11b and 14b are held in contact with each other. The tips of the holding claws 11b and 14b may be shaped as shown in FIG.

  Next, a method of holding the wafer 5 using the holding claws having the above configuration will be described with reference to FIG.

  When the wafer 5 is supplied to the spindle 6 by the transfer arm 10 shown in FIG. 6, as shown in FIG. 4, the holding claw 11b is sufficiently outside the inner peripheral edge of the spindle 6 by an external actuator (not shown). The holding claw 14b is closed inward from the inner peripheral surface of the spindle 6 to the position of the stopper 17 toward the center.

Wafer 5 in this state is supplied together the center of the wafer 5 to the position O _W that dropped from the center position O _S of the spindle 6 by a distance a. At this stage, the wafer 5 is not held by the holding claws 11b, 14a, 14b, and the shortest vertical distance b between the holding claws 14a and the wafer 5 is the shortest vertical distance c between the holding claws 14b and the wafer 5. The distance c is larger than the distance a.

Next, the wafer 5 is increased toward the center position O _S of the spindle 6 by the transfer arm 10 into contact with the groove of the V-shape of the holding claws 14b tip surface. The wafer 5 comes into contact with the V-shaped groove on the front end surface of the holding claw 14b, so that the posture of the wafer 5 in the thickness direction is regulated.

Further, the holding claw 14b is movable, and the wafer 5 is raised in a state where the posture in the thickness direction is regulated by the holding claw 14b, and the wafer 5 contacts the front end surface of the holding claw 14a. When the wafer 5 comes into contact with the front end surface of the holding claw 14a, the vertical position of the wafer 5 is regulated. The position of the holding claw 14 a is attached so that the center of the wafer 5 becomes the center position O _S of the spindle 6 when the wafer 5 is positioned.

  Next, the holding claws 11 b that have been opened outside the inner peripheral edge of the spindle 6 are closed inward until they contact the wafer 5.

  The wafer 5 is held by the above operation, and the wafer flatness measuring sensor 9 which is an optical displacement meter is moved in the X-axis direction while rotating the spindle 6, and the flatness of the surface of the wafer 5 attached to the spindle 6 is moved. Measure.

  According to one embodiment of the present invention, the posture adjustment in the thickness direction of the wafer 5 in the spindle 6 is performed by the holding claws 11b and 14b, and the position adjustment of the center of the wafer 5 is performed by the holding claws 11b and 14a. The center position of the wafer 5 can be adjusted at the outer diameter portion of the wafer 5 with higher accuracy, and the variation of the center position of the wafer 5 in the spindle 6 can be reduced to half or less. Accurate measurement can be performed.

  Further, by separating the holding claw 14b for adjusting the position of the wafer 5 in the thickness direction and the holding claw 14a for adjusting the center position of the wafer, the center position of the wafer 5 held by wear over time as compared with the prior art. It is possible to reduce the variation of the holding claws to half or less, and the holding claw replacement operation can be reduced to half or less.

  In the embodiment of the present invention, the wafer flatness measurement sensor has been described as an optical displacement meter. However, any sensor capable of measuring the thickness and shape of the wafer surface may be used. For example, a capacitance sensor or the like may be used. It may be used.

  The thin plate material holding method and measuring apparatus of the present invention can also be applied to applications such as holding thin plate materials such as semiconductor manufacturing wafers and magnetic disk substrates.

The schematic block diagram of the holding | maintenance part in embodiment of this invention Cross-sectional shape diagram of a holding claw in an embodiment of the present invention Cross-sectional shape diagram of a holding claw in an embodiment of the present invention Explanatory drawing of wafer correction in embodiment of this invention Schematic configuration diagram of a conventional flatness measuring device Schematic configuration diagram of transfer unit of conventional flatness measuring device Cross-sectional shape diagram of conventional holding claws

Explanation of symbols

5 Wafer 6 Spindle 11b Holding claw 14a Holding claw 14b Holding claw 15 Rotating shaft 16 Spring (elastic member)
17 Stopper

Claims (10)

After the sheet material is brought into contact with the first holding claw and the thickness direction is regulated, the sheet material is moved in the direction in which the first holding claw is in a state where the sheet material is brought into contact with the first holding claw to change the thickness direction. A second holding claw to regulate the center position of the thin plate material, and a third holding claw in a position facing the second holding claw in a state of being in contact with the second holding claw The thin plate material is held in contact with the thin plate material, the measurement sensor is moved in the radial direction of the thin plate material while rotating the held thin plate material, and the displacement of the thin plate material surface is measured. Method for measuring thin plate materials. 2. The method for measuring a thin plate material according to claim 1, wherein the displacement of the surface of the thin plate material is measured from both sides of the thin plate material. 3. The method for measuring a thin plate material according to claim 1, wherein the thin plate material is a wafer. A spindle that rotates the thin plate material, a first holding claw that is attached to the periphery of the spindle and regulates the thickness direction of the thin plate material, and a second that is attached to the periphery of the spindle and regulates the center position of the thin plate material A third holding claw that is attached to the periphery of the spindle that faces the first holding claw and the second holding claw and regulates the thickness direction and the center position of the thin plate material, An apparatus for measuring a thin plate material, comprising: a measurement unit that measures the displacement of the surface of the thin plate material; and a moving mechanism that moves the measurement unit in a radial direction of the thin plate material. The thin plate material measuring apparatus according to claim 4, wherein at least two of the first holding claws and the second holding claws are provided. 6. The apparatus for measuring a thin plate material according to claim 4, wherein a V-shaped groove is provided on the tip surfaces of the first holding claw and the third holding claw. The thin plate material measuring apparatus according to any one of claims 4 to 6, wherein the measurement unit is provided on both sides of the thin plate material. The thin plate material measuring apparatus according to any one of claims 4 to 7, wherein the thin plate material is held vertically. 9. The thin plate material measuring apparatus according to claim 4, wherein the measuring unit is an optical displacement meter. The thin plate material measuring apparatus according to any one of claims 4 to 9, wherein the thin plate material is a wafer.

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