JP5910231B2 - Pattern dimension measuring apparatus and pattern dimension measuring method - Google Patents

Description

  The present invention relates to a pattern dimension measuring apparatus and a pattern dimension measuring method for measuring a dimension of a pattern.

  For quality control and the like, the size of a fine pattern of a planar sample such as a glass mask for semiconductor manufacturing may be measured. As a measurement apparatus for performing such a measurement, an apparatus that performs dimension measurement while relatively moving a sample and an optical system such as a camera using a moving stage is known (Patent Document 1, etc.). .

Japanese Utility Model Publication No. 4-61010

  However, in the conventional measuring apparatus using an optical system and a moving stage, measurement is often performed by temporarily stopping the moving stage for each measurement point, and a large number of measurement points are measured like a repetitive pattern such as a striped pattern. Had the problem of taking time. Some objects that require measurement of a minute length have a measurement time defined for the purpose of preventing the influence of temperature and humidity. Therefore, it is desirable to make the measurement time as short as possible.

  In the measuring apparatus of Patent Document 1, the moving distance of the moving stage is measured for measurement. In such a case, there is a problem that the measurement result depends on the accuracy of the device that measures the moving distance.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a pattern dimension measuring apparatus and the like that can accurately measure a pattern dimension in a short time.

A first invention for achieving the above-described object is a pattern dimension measuring device for measuring a dimension of a pattern of an object, a measurement table, and an imaging device movable relative to the measurement table. An information processing device and a calibration pattern having a scale at a predetermined interval along the moving direction of the imaging device, and the imaging device moves relative to the measurement table while moving relative to the measurement table. The arranged object is imaged together with the calibration pattern, and the information processing apparatus is configured to capture the object pattern and the calibration pattern from the image captured by the imaging apparatus based on the calibration pattern scale. the dimensions were measured, the object is a retardation film having a pattern orientation consists of two different areas, on the imaging device, one Ryo Polarizing filters corresponding to the orientation direction of a pattern dimension measuring apparatus according to claim Rukoto provided.

In the present invention, the object and the calibration pattern arranged on the measurement table are imaged while moving the imaging device without stopping, and the dimensions of the object pattern are measured based on the scale of the calibration pattern using this image. To do.
Therefore, for example, even a pattern such as a striped pattern on a belt-like object can be quickly measured. Further, in the present invention, the object is imaged while moving the image pickup apparatus, and therefore, when the moving speed of the image pickup apparatus is uneven, the dimension of the pattern of the object expands and contracts on the image. However, since the scale of the calibration pattern similarly expands and contracts at this time, the exact dimension of the pattern can be measured based on the scale having a known interval. In this way, high-accuracy dimension measurement can be performed simply by imaging the object simultaneously with the calibration pattern, so that high-accuracy positioning of the imaging device and the object is not necessary, and the apparatus can be easily configured.

In addition, it is preferable to further include an illumination device that irradiates the object with illumination light, and the illumination device is moved relative to the measurement table in the same direction as the imaging device in synchronization with the imaging device. .
Thereby, imaging of a target object can be performed suitably. Furthermore, since the illumination device moves in the same direction in synchronization with the imaging device, unevenness of illumination light does not affect the image.

Further, the object is a retardation film having a pattern composed of two regions having different orientation directions, and a polarizing filter corresponding to the orientation direction of one region is provided in the imaging device, Take an image. As a result, the two regions appear as a high-luminance portion and a low-luminance portion on the image, so that the pattern dimension can be suitably measured.

A second invention is a pattern dimension measuring method for measuring a dimension of a pattern of an object, wherein the object placed on the measurement table is moved while moving the imaging device relative to the measurement table. The calibration pattern is scaled from the image captured with the calibration pattern having a scale of a predetermined interval along the moving direction of the imaging device, and the information processing device images the object and the calibration pattern with the imaging device. Based on this, the dimension of the pattern of the object is measured, and the object is a retardation film having a pattern composed of two regions having different orientation directions, and corresponds to the orientation direction of one region in the imaging device. A pattern dimension measuring method , wherein a polarizing filter is provided .

When imaging the object, it is desirable that an illuminating device that irradiates the object with illumination light moves relative to the measurement table in the same direction as the imaging device in synchronization with the imaging device .

  According to the present invention, it is possible to provide a pattern dimension measuring apparatus and the like that can accurately measure a pattern dimension in a short time.

The figure which shows the pattern dimension measuring apparatus 1 Diagram showing calibration pattern 111 The figure explaining FPR film 21 Diagram explaining pattern dimension measurement The figure explaining the image data 30

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Configuration of pattern dimension measuring apparatus 1)
First, a pattern dimension measuring apparatus 1 according to this embodiment will be described with reference to FIG. As shown in the figure, the pattern dimension measuring apparatus 1 includes a measurement table 11, a transfer stage 12, a line camera 13, an illumination device 14, an information processing device 15, and the like.

  The measurement table 11 is a rectangular table on which measurement objects are arranged. An opening 11a is provided at the center of the measurement table 11 along the long side direction of the table, and a transparent glass 11b is fitted into the opening 11a. As the glass 11b, quartz glass or the like that does not change in length due to thermal expansion is used. In the present embodiment, the long side direction of the table is the moving direction of the line camera 13 described later.

  As shown in FIG. 2, a calibration pattern 111 is provided on one side of the glass 11b. The calibration pattern 111 is a scale having a known predetermined interval L along the table long side direction.

  The measurement table 11 is provided with a transfer stage 12. The transfer stage 12 spans the moving unit 12b of the line camera 13 between the gate-shaped support units 12a and 12a provided at both ends of the measurement table 11 in the long side direction of the table.

The line camera 13 is an imaging device that images the object and the calibration pattern 111, and can be moved in the table long side direction along the moving unit 12b by a driving unit such as a motor. A polarizing filter 13 a is attached to the light receiving portion of the line camera 13. This polarizing filter 13a is an FPR (Film), which will be described later.
Patterned Retarder) The orientation direction is the same direction as the orientation direction of one region of the film. It should be noted that other imaging devices can be used instead of the line camera 13.

  The illumination device 14 is provided below the measurement table 11 and irradiates illumination light upward toward the opening 11a. The illuminating device 14 can be moved by a driving means such as a motor along a moving portion 16 provided in the long side direction of the table. When measuring the pattern dimension, the illumination device 14 moves in the same direction in synchronization with the line camera 13.

  The information processing device 15 controls the measurement by controlling the movement of the line camera 13 and the illumination device 14, acquires the object imaged by the line camera 13 and the image of the calibration pattern 111, and uses this to obtain the object. Measure the dimensions of the pattern. The information processing apparatus 15 can be realized by a general computer including a control unit, a storage unit, a communication unit, a display unit, and the like.

  In the present embodiment, the measurement object is an FPR film used for a 3D display device or the like. As shown in FIG. 3, the FPR film 21 is a belt-like retardation film having a pattern in which two regions 21 a and 21 b having orientation directions orthogonal to each other (indicated by arrows in the figure) are alternately repeated in the film longitudinal direction. is there.

(Measurement by the pattern dimension measuring device 1)
Next, measurement of the pattern dimension of the FPR film 21 by the pattern dimension measuring apparatus 1 will be described. 4A and 4B are diagrams showing measurement of pattern dimensions, FIG. 4A is a view of the top surface of the measurement table 11, and FIG. 4B is a view of the vertical cross section of the measurement table 11. In FIG. 4B, reference numeral 131 denotes an imaging range by the line camera 13.

  In order to measure the pattern dimensions of the FPR film 21, first, as shown in FIGS. 4A and 4B, the film longitudinal direction of the FPR film 21 is made to correspond to the table long side direction, and calibration on the glass 11b is performed. It is arranged on the side of the pattern 111. Moreover, in order to fix the position of the FPR film 21, the transparent suppression glass 17 is mounted on top. However, the method of fixing the position of the FPR film 21 is not limited to this.

  Next, the FPR illuminated by the illumination device 14 by the line camera 13 while moving the line camera 13 and the illumination device 14 without stopping in the film longitudinal direction of the FPR film 21 indicated by the arrow in FIG. The film 21 and the calibration pattern 111 are imaged.

  FIG. 5 shows an example of the image data 30 obtained by imaging the FPR film 21 in this way. 5A is a diagram showing a part of the image data 30, FIG. 5B is a diagram showing the range 31, and FIG. 5C is a diagram showing the range 33.

  As shown in FIG. 5, on the image data 30, the region 21b of the FPR film 21 whose alignment direction coincides with the polarizing filter 13a is displayed with high luminance, and the region 21a of the alignment direction orthogonal to this is displayed with low luminance. The These regions are alternately repeated along the film longitudinal direction to form a striped pattern. Further, the scale of the calibration pattern 111 is displayed on the side of the FPR film 21.

  The information processing device 15 measures the width of each region 21a, 21b of the FPR film 21 based on the scale of the calibration pattern 111 on the side.

  For example, the information processing device 15 first calculates the number of pixels between the scales of the calibration pattern 111 and compares it with a scale width in a known real space, and corresponds to a width of 1 pixel (hereinafter referred to as a pixel width). Calculate real space length. For example, when the number of pixels between the scales on the image data 30 is 10 pixels and the scale width on the real space is 50 microns, the real space length corresponding to the pixel width is calculated as 5 microns.

  The information processing device 15 is located on the side of the scale, and measures the length in the film longitudinal direction of the regions 21a and 21b corresponding to the scale using the calculated real space length per pixel width. For example, when the length of the region 21a (21b) is 50 pixels, this is multiplied by 5 microns, which is the actual space length per pixel width, and is calculated to be 250 microns.

In the image data 30, a range 31 is a portion where the line camera 13 is low speed at the time of imaging, and a range 33 is a portion where the line camera 13 is high speed at the time of imaging. As indicated by the ranges 31 and 33, when the moving speed of the line camera 13 is uneven, the pattern of the FPR film 21 expands and contracts in the longitudinal direction of the film on the image.
However, at this time, the scale width of the calibration pattern 111 similarly expands and contracts on the image, so the relationship between the scale width of the calibration pattern 111 and the lengths of the regions 21a and 21b of the FPR film 21 does not change. Therefore, when measuring the pattern dimension based on the scale width on the image, the measurement accuracy is not affected by the unevenness of the moving speed of the line camera 13.

  In this embodiment, the dimension in the film longitudinal direction is measured. However, the present invention is not limited to this. For example, when the film has a pattern in the film width direction, the dimension in the film width direction also corresponds to the corresponding scale width. Can be calculated based on That is, the length in the film width direction can be calculated by multiplying the number of pixels in the film width direction by the actual space length per pixel width.

As described above, according to the present embodiment, the FPR film 21 and the calibration pattern 111 arranged on the measurement table 11 are imaged while moving the line camera 13 and the like without stopping, and the FPR is based on the image data 30. The dimension of the pattern of the film 21 is measured. Therefore, it is possible to quickly measure dimensions.
Further, in this embodiment, since the image is taken while moving the line camera 13 or the like, the dimension of the pattern expands and contracts on the image when the moving speed is uneven. Similarly, the scale of the calibration pattern 111 also expands and contracts. The exact dimension of the pattern can be measured on the basis of a known scale. As described above, in this embodiment, high-precision dimension measurement can be performed only by imaging the FPR film 21 at the same time as the calibration pattern 111. Therefore, high-precision positioning of the line camera 13 and the FPR film 21 is not necessary, and the apparatus can be simplified. Can be configured.

  The pattern dimension measuring apparatus 1 includes an illuminating device 14 that irradiates the FPR film 21 with illuminating light, and the illuminating device 14 moves in the same direction in synchronization with the line camera 13. Further, the luminance on the image data 30 is not affected by the unevenness of the illumination light.

  In this embodiment, since the FPR film 21 having a pattern composed of two regions having different orientation directions is imaged through the polarizing filter 13a corresponding to the orientation direction of one region, there is a difference in the orientation direction. It appears as light and dark on the image, and the pattern dimension can be measured suitably.

  Note that the measurement target is not limited to the FPR film 21 described above, and any object having a pattern can be applied. As this pattern, there is a pattern due to a difference in color such as brightness or darkness of an object other than a pattern due to a difference in orientation direction as in the FPR film 21. In this case, the pattern dimension can be measured by omitting the polarizing filter 13a.

Further, in the present embodiment, the object is illuminated from the lower illumination device 14, but the illumination device 14 may be illuminated from above or may be omitted. In these cases, the opening 11a and the glass 11b of the measurement table 11 can be omitted.
Further, the calibration pattern 111 is not limited to the one formed on the glass 11 b, and another calibration pattern 111 may be positioned and placed on the measurement table 11.

  Further, in the present embodiment, imaging is performed while moving the line camera 13 and the illumination device 14, but conversely, it is also possible to perform imaging while moving the measurement table 11. That is, the line camera 13 and the illumination device 14 may be moved relative to the measurement table 11 at the time of imaging.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these naturally belong to the technical scope of the present invention. Understood.

1: Pattern dimension measuring device 11: Measurement table 11a: Opening portion 11b: Glass 12: Transport stage 13: Line camera 13a: Polarizing filter 14: Illumination 15: Information processing device 21: FPR film 30: Image data 111: Calibration pattern

Claims (4)

A pattern dimension measuring apparatus for measuring a dimension of a pattern of an object,
A measurement table;
An imaging device movable relative to the measurement table;
An information processing device;
A calibration pattern having graduations at predetermined intervals along the moving direction of the imaging device;
With
The imaging device images the object arranged on the measurement table together with the calibration pattern while moving relative to the measurement table,
The information processing apparatus measures the dimension of the pattern of the object based on a scale of the calibration pattern from an image obtained by imaging the object and the calibration pattern with the imaging apparatus ,
The object is a retardation film having a pattern composed of two regions having different orientation directions,
Wherein the imaging device, polarizing filter pattern dimension measuring apparatus according to claim Rukoto provided corresponding to the alignment direction of one of the regions. Further comprising an illumination device for illuminating the object with illumination light,
The pattern illuminating device according to claim 1, wherein the illumination device moves relative to the measurement table in the same direction as the imaging device in synchronization with the imaging device. A pattern dimension measuring method for measuring a dimension of a pattern of an object,
While moving the imaging device relative to the measurement table, the object placed on the measurement table is imaged together with a calibration pattern having graduations at predetermined intervals along the moving direction of the imaging device,
From an image obtained by imaging the object and the calibration pattern with the imaging device by the information processing device, measure the dimension of the pattern of the object based on the scale of the calibration pattern ,
The object is a retardation film having a pattern composed of two regions having different orientation directions,
On the imaging device, the pattern dimension measuring method polarizing filter and said Rukoto provided corresponding to the alignment direction of one of the regions. When imaging the object,
The pattern dimension according to claim 3 , wherein an illumination device that irradiates the object with illumination light moves relative to the measurement table in the same direction as the imaging device in synchronization with the imaging device. Measuring method.

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