JPH11241910A - Coordinate measuring device with temperature correcting function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the temperature in an optional position of a matter to be measured by using a non-contact type temperature measuring means in a short period of time. SOLUTION: A CPU 57 controls the position of temperature measuring position by a non-contact thermometer 3 and the position of image pickup of an object 1 to be measured by an area sensor, and measures the temperature of the position to which the non-contact thermometer 3 is opposed on the basis of the detection signal from the non-contact thermometer 3. It also measures the coordinates of a first and second reference positions and the coordinate of a third characteristic form part as the measuring position on the basis of the signal from an image processing unit 53. The coordinate of the measuring position of the object 1 is corrected according to the temperature change during measurement, and the corrected coordinate of the measuring position is converted into a coordinate at an intended temperature from the difference between the average temperature of the object 1 and the intended temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate measuring apparatus for measuring the coordinates of a characteristic shape portion such as a processing pattern on a substrate such as a photomask substrate or a color filter substrate used in a liquid crystal display device or the like. More particularly, the present invention relates to a coordinate measuring apparatus having a temperature correction function capable of correcting a measured value according to an ambient temperature for performing highly accurate measurement.

[0002]

2. Description of the Related Art Conventionally, when measuring the coordinates of a characteristic shape portion provided on the surface of an object to be measured or measuring the coordinates of a plurality of characteristic shape portions to determine a dimension therebetween, the measurement of the object to be measured is performed. The accuracy of coordinate measurement has been improved by measuring the temperature of an object to be measured and correcting the coordinate measurement value with the temperature measurement value in order to correct the change in the coordinates with the temperature. As means for measuring the temperature of an object to be measured, Japanese Patent Laid-Open Publication No.
No. 12 discloses an example using a contact-type temperature detection period.

[0003]

However, when a contact-type temperature detector is used, it takes a long time to measure the temperature, which makes it difficult to actually apply the method to coordinate measurement of an object to be measured. In addition, if a contact-type temperature detector is used, it is difficult to quickly measure the temperature at an arbitrary position on the measured object. Therefore, it is difficult to measure the temperature of each of the plurality of characteristic shapes on the DUT in order to accurately measure the coordinates of the plurality of characteristic shapes on the DUT. It was difficult to correct each coordinate accordingly.

[0004] The present invention has been made in view of the above,
An object of the present invention is to provide a coordinate measuring apparatus with a temperature correction function capable of reducing the coordinate measuring time by measuring the temperature of an object to be measured in a short time.

Another object of the present invention is to provide a coordinate measuring apparatus with a temperature correction function capable of improving the accuracy of coordinate measurement by quickly measuring the temperature at an arbitrary position on an object to be measured. I do.

[0006]

According to a first aspect of the present invention, there is provided a non-contact temperature detecting means for detecting a temperature of an object to be measured in a non-contact manner with respect to the object to be measured, and an imaging means for imaging the object to be measured. And, using coordinate measurement means for measuring the coordinates of at least one characteristic shape portion provided on the surface of the measured object using the imaging result of the imaging means, and using the detected temperature of the measured object, And a coordinate correcting means for correcting the measured coordinates of the characteristic shape portion.

[0007] According to this configuration, the temperature of the object to be measured is detected by the non-contact temperature detecting means in a non-contact manner with respect to the object to be measured, the image of the object to be measured is captured by the imaging means, and the imaging result is used by using the imaging result. The coordinates of the characteristic shape portion provided on the surface of the object to be measured are measured by the coordinate measuring means, and the measured coordinates of the characteristic shape portion are corrected using the temperature of the object to be measured. Is detected in a short time, and the measurement time of coordinate measurement is reduced.

According to a second aspect of the present invention, in the coordinate measuring apparatus with the temperature correcting function according to the first aspect, the non-contact temperature detecting means is provided on the object to be measured before the imaging means takes an image of the object. To detect the temperature at multiple locations
Detecting the temperature of the characteristic shape portion after imaging the object to be measured by the imaging means, wherein the coordinate correction means calculates the average value of the temperature detected before the imaging and the characteristic shape portion detected after the imaging. It is characterized in that the coordinates of the characteristic shape portion are corrected using the temperature difference from the temperature.

According to this structure, the temperatures of a plurality of positions on the object to be measured are detected before the imaging of the object to be measured by the imaging means, and the temperature of the characteristic shape portion is reduced after the imaging of the object to be measured by the imaging means. The coordinates of the characteristic shape portion are corrected by using the temperature difference between the average value of the temperature detected before the imaging and the temperature of the characteristic shape portion detected after the imaging by the coordinate correction means. Accordingly, the coordinates can be corrected according to the temperature change of the characteristic shape portion of the measured object during the measurement operation, and the measurement accuracy is improved.

[0010] The invention of claim 3 is based on claim 1 or 2.
The coordinate measuring apparatus with a temperature correction function described above is characterized in that a coordinate conversion means for converting the corrected coordinates of the characteristic shape portion into coordinates at a target temperature is provided.

According to this configuration, the corrected coordinates of the characteristic shape portion are converted into the coordinates at the target temperature, so that the coordinates of the characteristic shape portion at the target temperature can be obtained in a short time.

The object to be measured has a first characteristic shape portion, a second characteristic shape portion, and a third characteristic shape portion as the characteristic shape portion, and the non-contact temperature detecting means includes the first characteristic shape portion. Detecting the temperatures at a plurality of positions on the object to be measured before imaging the second, third, and third characteristic shape portions, and detecting the third characteristic shape portion after imaging the first, second, and third characteristic shape portions. The coordinate correction means detects the first temperature by the imaging means when the temperature difference is equal to or higher than a predetermined level.
The characteristic shape part and the second characteristic shape part are re-imaged, and the amount of change between the distance between the coordinates of the first characteristic shape part and the second characteristic shape part at the time of the first imaging and the distance at the time of re-imaging is When the temperature is equal to or higher than a predetermined level, the coordinates of the third characteristic shape portion may be corrected using the temperature difference.

According to this configuration, when the temperature difference between the average value of the temperatures at a plurality of positions of the object to be measured before the imaging and the temperature of the third characteristic shape portion after the imaging is equal to or more than the predetermined level, the first characteristic is obtained. The shape part and the second characteristic shape part are imaged again. When the amount of change between the distance between the coordinates of the first characteristic shape portion and the coordinates of the second characteristic shape portion at the time of the first imaging and the distance at the time of re-imaging is equal to or greater than a predetermined level, the temperature difference is calculated. By correcting the coordinates of the third characteristic shape portion using the correction, the coordinates can be corrected according to the temperature change during the measurement operation, and the coordinates of the third characteristic shape portion can be obtained with high accuracy.

[0014]

FIG. 1 is a block diagram of an embodiment of a coordinate measuring apparatus having a temperature compensation function according to the present invention, and FIG. 2 is a view showing an object to be measured 1 placed on a measuring table 2. 3A is a plan view, FIG. 3B is a front view, and FIG. This coordinate measuring device is for measuring the coordinates of the DUT 1, and includes a measuring table 2, a non-contact thermometer 3, an imaging device 4, a control unit 5, and the like, as shown in FIG.

The measuring table 2 is a rectangular flat plate on which the DUT 1 is placed, and is fixed to a stage 6. The stage 6 has a motor 7 composed of, for example, a stepping motor.
Is a driving source, and is configured to move with high accuracy in the left-right direction and the up-down direction in FIG.

The measuring table 2 is provided with support pieces 21 and 21 protruding along the upper side and support pieces 22 and 22 protruding along the left side in FIG. 2 (a) (b)
As shown in (1), the positioning of the DUT 1 to be mounted can be performed by the support pieces 21, 22, 22, and 22.

As shown in FIG. 2 (a), the coordinate measuring device uses a straight line connecting the lower ends of the support pieces 21 and 21 and a straight line connecting the right ends of the support pieces 22 and 22, as shown in FIG. An X, Y coordinate system set with the intersection point O as the origin.

The DUT 1 is, for example, a photomask substrate, a color filter substrate or a TFT used for a liquid crystal substrate.
It is made of a substrate or the like, and its surface is provided with a characteristic shape portion having a characteristic shape. This characteristic shape portion is a processed pattern such as each pixel of a liquid crystal and an alignment mark.

In the present embodiment, the DUT 1 has the first characteristic shape portion 11, the second characteristic shape portion 12, and the third characteristic shape portion 13a as the characteristic shape portions as shown in FIG.
To 13e. Among these characteristic shape portions, the first characteristic shape portion 11 has a function as a first reference position, and the second characteristic shape portion 12 has a function as a second reference position. Note that the first characteristic shape portion (hereinafter, referred to as “first reference position”) 11 and the second characteristic shape portion (hereinafter, referred to as “second reference position”) 12 are set at positions relatively distant from each other. Is preferred. Further, the third characteristic shape portions 13a to 13e each have a function as a measurement position.

Returning to FIG. 1, the non-contact thermometer 3 is a radiation thermometer fixed to the base 8 and electrically connected to the control unit 5 and provided with an infrared light receiving element 31 such as a thermopile. , And outputs a detection signal such as a voltage signal proportional to the temperature to the control unit 5.

The image pickup device 4 is electrically connected to the control unit 5, and comprises an epi-illumination system 41, a microscope unit 42, and a camera unit 43, as shown in FIG.

The epi-illumination system 41 includes a light source and a lens system (not shown), and irradiates the microscope section 42 with light in the horizontal direction. The microscope section 42 is at 45 ° with respect to the horizontal plane.
The optical system includes a half mirror 44 disposed at an angle, and a focusing lens 45 disposed below the half mirror 44 and having an optical axis disposed in a vertical direction.

The camera unit 43 has an area sensor 46, which is electrically connected to the control unit 5 and has two photoelectric conversion elements such as CCDs in the vertical and horizontal directions.
It is arranged in a dimensional manner and has a function as an image pickup means for picking up an image by light reflected from the DUT 1.

The light emitted from the epi-illumination system 41 is reflected by the half mirror 44, and the reflected light illuminates the DUT 1 via the focusing lens 45, and the DUT 1 passing through the focusing lens 45 Reflected light from the half mirror 4
4 to form an image on the area sensor 46, and an image signal of the area sensor 46 is sent to the control unit 5.

Returning to FIG. 1, the control unit 5 includes a motor control unit 51, an interface 52, an image processing unit 53,
A ROM 54, a RAM 55, a display unit 56, and a CPU 57 are provided. Each of the units 51 to 56 is electrically connected to the CPU 57.

The motor control section 51 controls a drive current such as a drive pulse signal supplied to the motor 7.
The interface 52 converts an analog value detection signal from the non-contact thermometer 3 into a digital value and sends it to the CPU 57. The image processing unit 53 performs A / D conversion, shading correction, and other image processing on the image pickup signal from the area sensor 46 and sends the image signal to the CPU 57.

The ROM 54 stores a control program for the coordinate measuring device, and the RAM 55 temporarily stores data and the like. The display unit 56 is an LCD
It consists of a panel and displays the measurement results.

The CPU 57 measures the coordinates of the device under test 1 in accordance with a procedure described later, and has the following functions. By controlling the position of the stage 6 by controlling the operation of the motor 7 via the motor control unit 51, the temperature measurement position of the DUT 1 by the non-contact thermometer 3 and the area sensor 57
Function for controlling the imaging position of the DUT 1 by the

Based on a signal from the image processing unit 53, a function as coordinate measuring means for measuring the coordinates of the first and second reference positions 11 and 12 and the coordinates of the third feature portions 13a to 13e as measurement positions. .

Function as coordinate correction means for correcting the coordinates of the measurement position of the DUT 1 in accordance with the temperature change during measurement. A function as coordinate conversion means for converting the coordinates of the corrected measurement position into coordinates at the target temperature from the difference between the average temperature of the DUT 1 and the target temperature. A function of controlling the display content of the display unit 56 based on the measurement result.

Next, referring to FIG. 2A, FIG.
The measurement procedure by the coordinate measuring device will be described with reference to the flowchart of FIG. First, at several points on the measuring table 2, for example, 6 of the temperature measuring positions 23,... Shown in FIG.
The temperature of the portions were measured and calculate the average T ₁ (# 10
0).

Next, the DUT 1 is set on the measurement table 2 (# 110), and several positions of the DUT 1, for example, FIG.
The temperatures at the six temperature measurement positions 10,... Shown in (a) are measured (# 120), and whether or not the temperatures at the temperature measurement positions 10,. Is 0.2 ℃
It is determined whether or not the following is true (# 130).

If it is not uniform (N in # 130)
O), after waiting for a predetermined time t ₁ (for example, 60 seconds) (# 14
0), returning to # 120, the temperature measurement position 1 of the DUT 1
Re-measure the temperature of 0,.

On the other hand, when the temperature of the DUT 1 becomes uniform (YES in # 130), the average value T ₂ of each temperature is calculated (# 150), and the temperature difference ΔTa between the DUT 1 and the measuring table 2 is calculated. It is calculated (# 160), and it is determined whether the temperature difference ΔTa is equal to or less than 0.2 ° C. (# 170).

If ΔTa> 0.2 ° C. (# 170)
NO), and after waiting for a predetermined time t ₂ (for example, 60 seconds) (#
180), returning to # 120, the temperature of the temperature measurement positions 10,... Of the DUT 1 is measured again.

On the other hand, if ΔTa ≦ 0.2 ° C. (YES in # 170), the coordinates of the first reference position 11 and the second reference position 1
2 are measured (# 190), and a dimension L0 between the reference positions is calculated by the following _equation (# 200).

[0037]

L ₀ = {{(Lx ₂ −Lx ₁ ) ² + (Ly ₂ −Ly ₁ ) ² } where the coordinates of the first reference position 11 measured at # 190 are (Lx ₁ , Ly ₁ ). , The coordinates of the second reference position 12 are (L
x ₂ , Ly ₂ ).

Next, the measurement position, for example, the third characteristic shape portion
13a is measured (# 210), and the temperature of the measurement position is measured.
Degree T_nIs measured (# 220). Then, the temperature T_nAnd average
Value T _TwoIs obtained (# 230), and the temperature difference ΔTb
It is determined whether Tb is 0.1 ° C. or less (# 240), and ΔTb ≦
If it is 0.1 ° C (YES in # 240), proceed to # 300
No.

On the other hand, if ΔTb> 0.1 ° C. (NO in # 240), the coordinates of the first reference position 11 and the second reference position 12
Are measured again (# 250), and a dimension L' ₀ between the reference positions is calculated by the following _equation (2) (# 260).

[0040]

L ′ ₀ = {{(Lx ′ ₂ −Lx ′ ₁ ) ² + (Ly ′ ₂ −Ly ′ ₁ ) ² } where the coordinates of the first reference position 11 re-measured in # 250 are (Lx ' ₁ , Ly' ₁ ) and the coordinates of the second reference position 12 are (Lx ' ₂ , Ly' ₂ ).

Next, the dimensions L ₀ calculated in # 200 and #
The dimension difference ΔL ₀ of the dimension L ′ ₀ calculated in 260 is calculated (#
270), it is determined whether or not the dimensional difference ΔL ₀ is 0.2 μm or less (# 280).

If ΔL ₀ ≦ 0.2 μm (# 28
YES 0), the change amount [Delta] x _n of the measured position coordinates, the [Delta] y _n as 0 (# 300), the process proceeds to # 310.

On the other hand, if ΔL ₀ > 0.2 μm (# 280
In NO), the change amount [Delta] x _n of the measured position coordinates, the [Delta] y _n is calculated by the following equation 3 (# 290).

[0044]

Equation 3] _{Δx n = Lx n · ΔTb ·} α Δy n = Ly n · ΔTb · α However, the coordinates of the measurement position measured by the # 210 (Lx _n,
Ly _n ) and the coefficient of thermal expansion of the DUT 1 is α.

Next, the coordinates of the measurement position are corrected to the coordinates at the average temperature T ₂ of the DUT 1 according to the following equation (4) (# 310).

[0046]

Equation 4] _{Lx 'n = Lx n -Δx n} Ly' n = Ly n -Δy n However, the coordinates of the measurement position measured by the # 210 (Lx _n,
And Ly _n), the coordinates in the average temperature T ₂ of the DUT 1 and _{(Lx 'n, Ly' n} ).

Next, all the measurement positions, in this embodiment the third measurement position
It is determined whether or not the measurement of the characteristic shapes 13a to 13e has been completed (# 320). If the measurement has not been completed (NO in # 320), the process returns to # 210 and the steps of # 210 to # 310 are repeated. .

On the other hand, when the measurement at all the measurement positions is completed (#
(YES at 320), the coordinates of the measurement position are converted into coordinates at the target temperature by the following equation (# 330), and the process ends.

[0049]

Equation 5] _{Lx '' n = Lx 'n} -Lx' n · (T 2 -Tm) · α Ly '' n = Ly 'n -Ly' n · (T 2 -Tm) · α where target temperature was a Tm, the coordinates in terms of purpose temperature _{(Lx '' n, Ly '} ' n).

As described above, since the non-contact thermometer 3 is used, the temperature at an arbitrary position can be measured in a short time. This makes it possible to measure the temperatures of the third characteristic shape portions 13a to 13e, which are the measurement positions, and correct each coordinate value according to the temperature change during the measurement. It can be obtained accurately and in a short time.

Therefore, it is not necessary to control the ambient temperature of the DUT 1 during the coordinate measurement to the target temperature. As a result, inspection of the position of a processing pattern on a substrate such as a manufactured photomask substrate or a color filter substrate and the dimensions of the substrate can be performed in close proximity to the substrate manufacturing line, thereby improving workability and efficiency of the substrate manufacturing. Can be improved.

The present invention is not limited to the above embodiment, but can adopt the following modifications (1) to (4). (1) In the above embodiment, a thermopile is used as the infrared light receiving element included in the non-contact thermometer 3. However, the present invention is not limited to this, and another infrared light receiving element such as a pyroelectric infrared sensor may be used.

(2) A plurality of thermal expansion coefficients α are stored in the ROM 54 for various materials, a dip switch is provided, and the on / off of the dip switches is switched in accordance with the material of the DUT 1, thereby calculating May be changeable.

(3) At # 240 in the flowchart of FIG. 5, it is determined whether the temperature difference ΔTb is 0.1 ° C. or less. However, the determination level is not limited to this. For example, the determination level is reduced to 0.05 ° C. For example, to improve measurement accuracy,
What is necessary is just to change according to the required measurement accuracy.

(4) In step # 280 of the flowchart of FIG. 5, it is determined whether or not the dimensional difference ΔL ₀ is 0.2 μm or less. However, the determination level is not limited to this. For example, the determination level is reduced to 0.1 μm. It may be changed according to the required measurement accuracy, for example, to improve the measurement accuracy.

[0056]

As described above, according to the first aspect of the present invention, the temperature of the object to be measured is detected by the non-contact temperature detecting means in a non-contact manner with respect to the object to be measured, and the temperature is measured by the imaging means. The object is imaged, the coordinates of the characteristic shape portion provided on the surface of the measured object are measured by the coordinate measuring means using the imaging result, and the measured coordinates of the characteristic shape portion are measured using the temperature of the measured object. Since the correction is performed, the temperature of the object to be measured can be detected in a short time, and the measurement time of coordinate measurement can be reduced.

According to the second aspect of the present invention, the temperature of a plurality of positions on the object to be measured is detected before the imaging of the object to be measured by the imaging means, and the characteristic is detected after the imaging of the object to be measured by the imaging means. By detecting the temperature of the shape portion, using the temperature difference between the average value of the temperature detected before the imaging and the temperature of the feature shape portion detected after the imaging, correcting the coordinates of the feature shape portion In addition, the coordinates can be corrected according to the temperature change of the characteristic shape portion of the measured object during the measurement operation, and the accuracy of the coordinate measurement can be improved.

According to the third aspect of the present invention, the coordinates of the characteristic shape portion at the target temperature can be obtained in a short time by converting the corrected coordinates of the characteristic shape portion into coordinates at the target temperature.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a coordinate measuring device with a temperature compensation function according to the present invention.

FIG. 2 is a diagram showing an object to be measured placed on a measuring table,
(A) is a plan view, and (b) is a front view.

FIG. 3 is a configuration diagram of an imaging device.

FIG. 4 is a flowchart showing a measurement procedure.

FIG. 5 is a flowchart showing a measurement procedure.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 object to be measured 2 measuring table 3 non-contact thermometer 4 imaging device 46 area sensor 5 control unit 54 ROM 55 RAM 57 CPU

Claims (3)

[Claims] A non-contact temperature detecting unit configured to detect a temperature of the measured object in a non-contact manner with respect to the measured object; an imaging unit configured to image the measured object; and an imaging result obtained by the imaging unit. Coordinate measuring means for measuring the coordinates of at least one characteristic shape portion provided on the surface of the object to be measured, and correcting the measured coordinates of the characteristic shape portion using the detected temperature of the object to be measured. A coordinate correcting device having a temperature correcting function. 2. A coordinate measuring apparatus with a temperature correction function according to claim 1, wherein said non-contact temperature detecting means measures the temperatures at a plurality of positions on the measured object before the imaging means takes an image of the measured object. Detecting and detecting the temperature of the characteristic shape portion after imaging the object to be measured by the imaging means, wherein the coordinate correcting means detects the average value of the temperature detected before the imaging and the temperature detected after the imaging. A coordinate measuring device with a temperature correction function, wherein the coordinates of the characteristic shape portion are corrected using a temperature difference from the temperature of the characteristic shape portion. 3. The temperature measuring apparatus according to claim 1, further comprising a coordinate conversion unit configured to convert the corrected coordinates of the characteristic shape portion into coordinates at a target temperature. Coordinate measuring device with correction function.