JP5076171B2 - Shape measuring method and shape measuring apparatus - Google Patents

Description

The present invention relates to a measuring method and measuring apparatus for measuring the surface shape and thickness of a thin plate, and more particularly to a measuring method and measuring apparatus for measuring the surface shape and thickness of a glass substrate.

  In general, as a method for measuring the surface shape of a thin plate, a method of continuously measuring the thickness of a silicon wafer, which is a thin plate, and its surface shape (for example, flatness) is known. For example, the thickness of each point is measured by a capacitive sensor while only the center of the silicon wafer is supported by the chuck, and then the thickness of the center is measured by shifting the support position of the chuck from the center. There is one in which the flatness is calculated based on data to be expressed (see Patent Document 1).

  Further, as an apparatus for measuring the thickness of the silicon wafer, the apparatus includes a turning means for supporting the silicon wafer, and a linear moving means that can be moved linearly on a plane by placing the turning means, and between the pair of displacement sensors. A silicon wafer is disposed on the silicon wafer, and the thickness is measured at each point of the silicon wafer by a displacement sensor (see Patent Document 2).

  In addition, as a device for measuring the thickness of a silicon wafer, a pair of distance sensors are arranged facing each other at a predetermined interval, and the peripheral portion of the silicon wafer is placed between the distance sensors by the wafer support portion. Both sides are supported so that they are almost perpendicular to the opposing direction of both distance sensors, and both distance sensors are supported by an air slide so as to be movable in a direction perpendicular to the opposing direction. There is one in which the thickness is measured while controlling the position with respect to (see Patent Document 3).

  In addition, as a device for measuring the thickness and flatness of a silicon wafer, a scanning sensor is mounted on an arm that is held on a rotor and linearly movable along an axis parallel to the rotation surface of the silicon wafer. , A spiral or other scanning path is realized, the thickness at each point of the silicon wafer is measured, and the flatness is obtained according to these thickness data (see Patent Document 4).

  Further, a thin plate such as a silicon wafer is rotatably supported in the same plane, and the first and second guide shafts are arranged in parallel to one side and the other side of the plane. The first and second sensors, which are arranged so as to be parallel to each other and move independently along the first and second guide axes, independently measure the distance to one surface and the other surface of the thin plate, There is one in which the surface shape of one surface and the other surface of a thin plate is measured (see Patent Document 5).

  Then, as a device for measuring the flatness of a thin plate material such as a silicon wafer, both sides of the thin plate material in an annular mounting base arranged to surround the thin plate material by rotating the thin plate material while being held by the thin plate material rotating means A pair of displacement sensors that measure the distance to the opposing surface of the thin plate material or a change in the distance are attached at symmetrical positions, and the mounting base is moved linearly by the measurement scanning means, so that the measurement position of the displacement sensor is There is one that scans in the direction of the radius of rotation (see Patent Document 6).

Japanese Patent Publication No. 5-77179 Japanese Utility Model Publication No. 64-10610 Japanese Utility Model Publication No. 6-49958 Japanese Patent No. 3197001 JP-A-11-351857 JP 2001-124542 A

  In the measurement apparatuses described in Patent Documents 1 to 6, a pair of measurement sensors (distance sensors, etc.) facing each other with a predetermined interval are arranged on both sides of the silicon wafer, and the silicon wafer surface is measured from each measurement sensor. Measure the distance to. And since the space | interval (distance between sensors) between a pair of measurement sensors is prescribed | regulated previously, the thickness of a silicon wafer is calculated | required according to the distance between sensors and the distance measured by each measurement sensor. Furthermore, if the thickness of the silicon wafer is continuously measured while moving each measurement sensor along the surface of the silicon wafer, the surface shape of the silicon silicon wafer can be measured.

  However, although the measuring devices described in Patent Documents 1 to 6 can measure the surface shape of a thin plate material such as a silicon wafer, it is difficult to accurately measure the surface shape of a thin plate material such as a glass substrate.

  In other words, with the widespread use of liquid crystal panels, there are various types of glass substrates such as frosted glass substrates and transparent substrates. For example, a laser beam is irradiated as a measurement sensor, and the reflected light reaches the glass substrate surface. When trying to measure the distance, the laser light passes through the glass substrate or diffusely reflects, causing mutual interference (hereinafter referred to as optical interference) in the measurement sensors arranged opposite to each other, and the glass is accurately obtained. There is a problem that the surface shape of the substrate cannot be measured.

An object of the present invention is to provide a shape measuring method及beauty shape measuring device that can of measuring accurately the surface shape and thickness of the glass substrate is thin.

In order to solve the above problems, the present invention relates to a pair of reflective sensors composed of a first sensor and a second sensor in a scanning direction along a thin plate disposed between the pair of reflective sensors. A measuring method for measuring the shape of the thin plate by moving the first sensor so that the first sensor is focused on the first surface of a reference gauge. Positioning the second sensor so that the second sensor is focused on the second surface of the reference gauge opposite to the first surface, and the pair of positioned reflective sensors A step of disposing a predetermined amount of displacement from each other in the scanning direction, and the pair of reflective sensors relative to the thin plate in the scanning direction along the thin plate while maintaining the predetermined amount of displacement. Automatically Scanning the surface of the thin plate to measure the surface shape of both surfaces of the thin plate, and calculating the thickness of the thin plate from the measured surface shape of both surfaces of the thin plate, It is a glass substrate, the reference gauge is made of glass , the first sensor is positioned with the second sensor retracted from the reference gauge, and the second sensor is positioned with the first sensor Is performed in a state of being retracted from the reference gauge .

Furthermore, according to the present invention, a pair of reflective sensors composed of the first sensor and the second sensor are relative to the thin plate in the scanning direction along the thin plate disposed between the pair of reflective sensors. A measuring apparatus for measuring the shape of the thin plate by moving the first sensor to the first surface of the reference gauge, wherein the pair of reflective sensors is focused on the first surface of the reference gauge. The second sensor is positioned so that the second sensor is in focus on the second surface opposite to the surface, and the first sensor and the second sensor are arranged to be shifted from each other by a predetermined amount in the scanning direction. The pair of reflective sensors are moved along the thin plate in the scanning direction relative to the thin plate while scanning the surface of the thin plate while maintaining the predetermined deviation amount. Get the surface shape of A means, a calculation means for calculating the thickness of the thin from both sides of the surface shape of the thin, the thin plate is a glass substrate, the reference gauge is made of glass, said first sensor, said With the second sensor retracted from the reference gauge, the second sensor is positioned so as to be focused on the first surface of the reference gauge, and the second sensor retracts the first sensor from the reference gauge. In such a state, a shape measuring device is obtained which is positioned so as to be focused on the second surface of the reference gauge .

  In the present invention, the scanning unit simultaneously scans the pair of reflective sensors along the surface of the thin plate, and the thin plate is, for example, a glass substrate.

As described above, in the present invention, a pair of reflective sensors are arranged at a predetermined interval, and are shifted from each other by a predetermined deviation amount on a plane orthogonal to a predetermined interval direction, so that the orthogonal surfaces are arranged. Since the thin plate and the pair of reflective sensors are relatively moved along the scanning surface to scan the thin plate surface, light interference occurs even if light from the pair of reflective sensors passes through the thin plate or is irregularly reflected. Without being able to accurately measure the surface shape of the thin plate.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention only to the description unless otherwise specified. It is just an example.

  Referring to FIG. 1, FIG. 1 is a side view showing an example of a surface shape measuring apparatus according to the present invention, and the illustrated surface shape measuring apparatus is used when measuring the surface shape of a thin plate such as a glass substrate. That is, the thin plate is a transparent or frosted glass substrate. The surface shape measuring apparatus has a base 10 on which a substrate vertical holding mechanism 10a and a measuring mechanism 10b are mounted.

  The substrate vertical holding mechanism 10a has a lower holding part 21 and an upper holding part 22, and the lower holding part 21 is disposed on the base 10 and includes a pair of holding members 21a and 21b protruding upward in the drawing. These holding members 21a and 21b are movable in the left-right direction in the figure, and the holding members 21a and 21b are adjusted according to the width (size) of the glass substrate W.

  A column portion 22a is planted on the rear side of the base 10, and a vertical screw feed mechanism 22b (for example, a ball screw) is mounted along the column portion 22a. Then, the mounting member 22c is mounted on the drive nut constituting the vertical screw feed mechanism 22b, the upper holding portion 22 is mounted on the lower end of the mounting member 22c, and the upper holding portion 22 is adjusted to the size of the glass substrate W. The position is adjusted. The glass substrate W is held by the pair of holding members 21 a and 21 b and the upper holding portion 22.

  That is, the lower holding portion 21 holds the lower end of the glass substrate W at two locations, and the upper holding portion 22 holds the upper end of the glass substrate W at one central portion (that is, the substrate vertical holding mechanism 10a holds the glass substrate W. It will be held vertically at three locations).

  The measurement mechanism 10b has vertical slide devices 30 and 40, and these vertical slide mechanisms 30 and 40 are vertically planted and arranged at both left and right ends in the drawing on the base 10, respectively. Screw feed mechanisms 50 and 60 such as ball screws are arranged inside the vertical slide devices 30 and 40, respectively.

  As shown in the figure, the vertical slide devices 30 and 40 are provided with slide members 31 and 41 that slide in the vertical direction (vertical direction), and a measuring unit moving mechanism 70 is connected to the slide members 31 and 41. The measuring unit moving mechanism 70 is movable in the horizontal direction as will be described later.

  As shown in the figure, a drive unit 80 such as a motor is disposed at the right end of the base 10, and this drive unit 80 is connected to the screw feed mechanisms 50 and 60 via a connecting unit (not shown). Yes. Thereby, the rotational driving force of the drive unit 80 is simultaneously transmitted to the screw feed mechanisms 50 and 60. The screw feed mechanisms 50 and 60 are provided with nut portions 51 and 61, respectively. Slide members 31 and 41 are integrally attached to the nut portions 51 and 61, and when the drive unit 80 rotates, the slide members 31 and 41 are moved. By sliding in the vertical direction, the measurement unit moving mechanism 70 moves in the vertical direction.

Here, referring also to FIG. 2, the measuring unit moving mechanism 70 has a length larger than the width of the glass substrate W, which is the object to be measured, and a pair of slide rail units arranged in parallel at a predetermined interval. 71 and 72, and the slide rail portions 71 and 72 extend in the width direction of the glass substrate W. Slide members 73 and 74 are mounted on the slide rail portions 71 and 72 so as to be movable in the horizontal direction, and measuring portions (for example, displacement sensors (a pair of reflective sensors) are mounted on opposing surfaces of the slide members 73 and 74, respectively. )) 75 and 76 are attached, and the measuring parts 75 and 76 are arranged at positions facing each other with the glass substrate W interposed therebetween.

  In the above-described example, the vertical slide devices 30 and 40 are configured by air slides, and the measurement unit moving mechanism 70 is configured by a linear motor mechanism. Further, both end portions of the slide rail portions 71 and 72 are placed on attachment members 32 and 42 fixed to the side portions of the slide members 31 and 41.

  In the surface shape measuring apparatus shown in FIG. 1, the glass substrate W is vertically held by the substrate vertical holding mechanism 10a as described above, and the measuring unit moving mechanism 70, that is, the slide members 73 and 74 are moved in the XY directions. Control. As a result, the measuring units 75 and 76 move along the surface of the glass substrate W and measure the surface shape of the glass substrate W in a non-contact manner (for example, the flatness is measured continuously or intermittently, The thickness of the glass substrate W is calculated from the measurement results obtained by the measurement units 75 and 76).

  Here, in order to easily understand the measurement technique according to the present invention, the conventional measurement technique will be outlined. Referring to FIG. 3, a thickness reference gauge G (for example, a gauge made of quartz glass that is close to the thickness of the glass substrate) is sandwiched, and the displacement sensors 75 and 76 are focused to face each other as indicated by solid arrows. Arrange on the same line. And the glass substrate W which is a to-be-measured object is arrange | positioned between the displacement sensors 75 and 76, and the displacement sensors 75 and 76 are scanned as shown by the solid line arrow in FIG. Measure thickness and surface shape.

  When the thickness of the glass substrate W is different from the thickness of the thickness reference gauge G, for example, the positions of the displacement sensors 75 and 76 are moved in the direction indicated by the solid line arrow in FIG. Measurements are taken after focusing 75 and 76.

  By the way, in the measurement method demonstrated in FIG.3 and FIG.4, since the displacement sensors 75 and 76 are positioned in the mutually opposing state and the displacement sensors 75 and 76 are scanned, is the glass substrate W a thin transparent substrate? Or if it is a frosted glass substrate, the light from the displacement sensors 75 and 76 will be transmitted through the glass substrate or irregularly reflected, causing optical interference, and the surface shape of the glass substrate cannot be measured accurately.

  In order to prevent such a problem, in this example, the surface shape of the glass substrate W was measured as follows. First, as shown by the solid line arrow in FIG. 5A, the displacement sensor 75 is retracted, the thickness reference gauge G and the displacement sensor 76 are opposed, and the displacement sensor 76 is focused as shown by the solid line arrow. Then, the displacement sensor 76 is positioned. Subsequently, as shown by the solid line arrow in FIG. 5B, the displacement sensor 76 is retracted, the thickness reference gauge G and the displacement sensor 75 are made to face each other, and the focus of the displacement sensor 75 is made as shown by the solid line arrow. In addition, the displacement sensor 75 is positioned.

  In this way, the displacement sensors 75 and 76 are positioned. In the example shown in FIG. 1, the displacement sensors 75 and 76 are already positioned, and the displacement sensors 75 and 76 are also in the scanning direction. They are shifted in the (horizontal direction) by a predetermined distance (shift amount (for example, 25 mm)).

  Referring to FIG. 6, the displacement sensors 75 and 76 are arranged to be shifted by a predetermined shift amount in the scanning direction (horizontal direction in FIG. 1), and the displacement sensors 75 and 76 are directions indicated by solid arrows in FIG. And the surface shape of the glass substrate W is measured. At this time, since the displacement sensors 75 and 76 are shifted by a predetermined shift amount P, even if the glass substrate W is a thin transparent substrate or a ground glass substrate, optical interference can be given to each other. The surface shape of the glass substrate W can be accurately measured.

  The distance between the displacement sensors 75 and 76 and the measured value of the displacement sensor 76 (distance between the glass substrate W and the displacement sensor 76) and the measured value of the displacement sensor 75 after scanning a predetermined amount of deviation (the glass substrate W and the displacement sensor). And the thickness of the glass substrate W. Moreover, although the example which hold | maintained the glass substrate W vertically was demonstrated in the above-mentioned example, when the glass substrate W is hold | maintained horizontally, the surface shape of the glass substrate W can be measured similarly. Alternatively, the glass substrate W may be moved with the displacement sensors 75 and 76 fixed.

A pair of reflective sensors are arranged at a predetermined interval, and are arranged by being shifted from each other by a predetermined deviation amount on a plane orthogonal to the predetermined interval direction, and the thin plate and the pair of reflective sensors are arranged along the orthogonal plane. Since the thin plate surface is scanned by relatively moving the light, the surface shape of the thin plate can be accurately obtained without causing light interference even if light from a pair of reflective sensors passes through the thin plate or is irregularly reflected. Can be applied to the surface shape measurement of various thin plates.

It is a figure which shows an example of the surface shape measuring apparatus by this invention from the side. It is a figure which shows the measurement part moving mechanism used with the surface shape measuring apparatus shown in FIG. 1 from the AA line direction of FIG. It is a figure for demonstrating focusing of the displacement sensor at the time of performing the conventional surface shape measuring method. It is a figure for demonstrating the conventional surface shape measuring method, (a) is a figure which shows the scanning direction of a displacement sensor, (b) is the refocusing of the displacement sensor when a glass substrate is thinner than a thickness reference gauge. It is a figure for demonstrating. It is a figure for demonstrating focusing of the displacement sensor at the time of performing the surface shape measuring method by this invention, (a) is a figure which shows focusing of one displacement sensor, (b) is a focus of the other displacement sensor. FIG. It is a figure for demonstrating an example of the surface shape measuring method by this invention.

Explanation of symbols

10 base (base)
10a Substrate vertical holding mechanism 10b Measuring mechanism 21 Lower holding part 22 Upper holding part 21a, 21b Holding member 22a Column part 22b Vertical screw feeding mechanism 22c, 32, 42 Mounting member 30, 40 Vertical sliding device 50, 60 Screw feeding mechanism 31, 41 Slide member 70 Measuring unit moving mechanism 80 Drive unit 51, 61 Nut unit 71, 72 Slide rail unit 73, 74 Slide member 75, 76 Measuring unit (displacement sensor (a pair of reflective sensors))

Claims (3)

A pair of reflective sensors composed of a first sensor and a second sensor are moved relative to the thin plate in the scanning direction along the thin plate disposed between the pair of reflective sensors. A measuring method for measuring a shape,
Positioning the first sensor such that the first sensor is in focus with a first surface of a reference gauge;
Positioning the second sensor so that the second sensor is in focus on the second surface of the reference gauge opposite to the first surface;
Disposing and positioning the pair of positioned reflective sensors in the scanning direction by a predetermined deviation amount;
While maintaining the predetermined shift amount, the pair of reflective sensors are moved along the thin plate in the scanning direction relative to the thin plate to scan the surface of the thin plate and Measuring a surface shape;
Calculating the thickness of the thin plate from the measured surface shape of both surfaces of the thin plate,
The thin plate is a glass substrate, the reference gauge is made of glass ,
The positioning of the first sensor is performed with the second sensor retracted from the reference gauge,
The shape measuring method , wherein the positioning of the second sensor is performed in a state where the first sensor is retracted from the reference gauge .   The shape measuring method according to claim 1, wherein in the step of obtaining the surface shape of the thin plate, the pair of reflective sensors are simultaneously scanned along the surface of the thin plate. A pair of reflective sensors composed of a first sensor and a second sensor are moved relative to the thin plate in the scanning direction along the thin plate disposed between the pair of reflective sensors. A measuring device for measuring a shape,
In the pair of reflective sensors, the first sensor is focused on the first surface of the reference gauge, and the second sensor is focused on the second surface of the reference gauge opposite to the first surface. Is positioned on
The first sensor and the second sensor are arranged to be shifted from each other by a predetermined amount in the scanning direction,
While maintaining the predetermined shift amount, the pair of reflective sensors are moved along the thin plate in the scanning direction relative to the thin plate to scan the surface of the thin plate and Scanning means for obtaining a surface shape;
Calculating means for calculating the thickness of the thin plate from the surface shape of both surfaces of the thin plate;
The thin plate is a glass substrate, the reference gauge is made of glass,
  The first sensor is positioned so as to be focused on the first surface of the reference gauge in a state where the second sensor is retracted from the reference gauge.
The shape measuring apparatus, wherein the second sensor is positioned so as to be focused on the second surface of the reference gauge in a state where the first sensor is retracted from the reference gauge.

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