JPH09280825A - Position detecting method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a position with a high precision by using an integrating area sensor. SOLUTION: By taking a picture signal output from an integrating type area sensor 1 into a comparison circuit 21 synchronizing with scanning clock ϕsc ; comparing this picture signal level with a threshold and detecting change in the picture signal level; controlling an amount of a movement of a photomask 2 and the integrating type area sensor 1 in each scanning clock ϕsc by a movement control circuit 22 at a slower speed than the one at which the moving speed of the image of the photomask 2 projected to the integrating type area sensor 1 forwards charges between pixels at this time; reading of an image pickup position of the photomask 2 measured by a laser measuring system 23 when the picture signal level is reversed, and this is defined as an edge position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting method and apparatus for detecting the position of a pattern edge formed on a photomask, for example.

[0002]

2. Description of the Related Art For example, as a photomask, one having a light-shielding film mask pattern formed of a Cr film or the like on a glass substrate or one having a semitransparent film mask pattern formed of a metal oxide film or the like on a glass substrate is known. For these photomasks, the edge position of the mask pattern is detected.

In such a position detecting device, a line sensor is arranged above a photomask which is an object to be inspected, and for example, the photomask is moved, and at this time, the line sensor picks up an image of the photomask and outputs an image signal thereof. Is output.

At the same time, the position of the moving photomask, that is, the image pickup position of the line sensor with respect to the photomask is measured by the laser measuring system. Then, the image signal output from the line sensor is captured in a comparison circuit, and in this comparison circuit, the image signal of the line sensor and a certain threshold value are compared in synchronization with the image capture cycle of the line sensor. Then, it is detected that the image signal level has changed.

From the comparison result, when the image signal level changes, the image pickup position for the photomask measured by the laser length measurement system is taken in, and this image pickup position is measured as the position of the pattern edge.

[0006]

By the way, as a line sensor used for such position detection, there is, for example, a time delay integration type (TDI) area sensor (hereinafter referred to as an integration type area sensor).

As shown in FIG. 10, this integrating type area sensor 1 has M pixels arranged in the vertical direction and N pixels arranged in the horizontal direction, and each pixel accumulates a charge amount corresponding to the brightness of a photomask. , Each charge accumulated in 1 to N pixels in the horizontal direction for each scan clock is sequentially transferred to 1 to N pixels adjacent in the horizontal direction, and the respective charge amounts are integrated. The accumulated charges of 1 to N pixels are output as an image signal.

Therefore, the image signal output from the integrating area sensor 1 is an integration of charges for M pixels in the vertical direction, and a sensor output having a higher sensitivity than that of a normal line sensor can be obtained.

For example, when the integrated area sensor 1 is scanned on the photomask 2 to detect the edge position as shown in FIG. 11, the integrated area sensor 1 is arranged in the same direction with respect to the edge, and with respect to the edge. If you move vertically,
The image signal level output from the integration area sensor 1 is
As shown in FIG. 12, the signal level corresponding to the edge sharply changes.

However, the image signal output from the integrated area sensor 1 changes in signal level according to the interval of the scan clock and the moving speed of the photomask. Therefore, even if the image signal level sharply changes. , At this time, it is unreliable whether it is the true edge position. Therefore, an object of the present invention is to provide a position detection method and a device therefor capable of highly accurate position detection using an integrated area sensor.

[0011]

According to a first aspect of the present invention, an object to be inspected and an image pickup device are moved relative to each other, and an image pickup position of the object to be inspected by the image pickup device is measured to detect an image signal level of the image pickup device. In a position detection method for reading the image pickup position of an object to be inspected at the time of change, the image pickup device accumulates a charge amount corresponding to the brightness of the object to be inspected in each pixel, and sequentially transfers and integrates the charge between these pixels to obtain an image. It is a position detection method that has a function of outputting a signal and that controls the moving speed of an image of an object to be inspected projected on an imaging device to be slower than the speed at which charges are transferred between pixels.

With such a position detecting method, the moving speed of the image of the object to be inspected projected on the image pickup device is controlled to be slower than the speed at which charges are transferred between pixels, so that, for example, this image signal is kept constant. The accuracy in detecting the edge position is higher than that of the threshold value.

According to a second aspect of the present invention, in the position detecting method according to the first aspect, the image pickup device sequentially transfers and integrates charges between a plurality of pixels for each scan clock, and integrates after a predetermined number of scan clocks. Output the electric charge as an image signal, and the moving speed of the image of the inspected object projected on the imaging device is slower than the speed at which the charge is transferred between pixels, and the inspected object and the imaging device at each scan clock. Control the amount of movement of.

According to such a position detecting method, the moving amount between the object to be inspected and the image pickup device for each scan clock of the image pickup device is determined by the moving speed of the image of the object to be inspected projected on the image pickup device between pixels. By controlling at a speed slower than the charge transfer speed, the change in the positions of the object to be inspected and the image pickup device for each scan clock becomes small, and the change in the image signal level of the image pickup device becomes slow.

According to the third aspect of the present invention, the object to be inspected and the image pickup device are moved relative to each other, the image pickup position of the object to be inspected by the image pickup device is measured, and the object to be inspected is changed when the image signal level of the image pickup device changes. In a position detection device for reading an image pickup position, the image pickup device has a function of accumulating an electric charge amount corresponding to the brightness of an object to be inspected in each pixel, sequentially transferring electric charges between these pixels, integrating the same, and outputting an image signal. And a moving mechanism that relatively moves the object to be inspected and the imaging device at a speed at which the image of the object to be inspected projected on the imaging device is slower than the speed at which charges are transferred between pixels. It is a position detection device.

With such a position detecting device, the relative moving speed between the object to be inspected and the image pickup device by the moving mechanism is
Since the moving speed of the image of the inspection object projected on the imaging device is controlled at a speed slower than the speed at which the charge is transferred between the pixels,
For example, the accuracy of detecting the edge position by comparing this image signal with a fixed threshold value becomes high.

According to a fourth aspect, in the position detecting apparatus according to the fourth aspect, the image pickup device accumulates the charge amount corresponding to the brightness of the object to be inspected in each pixel, and between these pixels, every scan clock. The charges are sequentially transferred and integrated, and after the predetermined number of scan clocks, the integrated charges are output as an image signal, and the moving mechanism is configured such that the moving speed of the image of the inspection object projected on the imaging device is the same between the pixels. It has a function of controlling the movement amount of the object to be inspected and the imaging device at each scan clock at a slower speed than the transfer speed.

In such a position detecting device, the moving mechanism determines the amount of movement between the object to be inspected and the image pickup device at each scan clock of the image pickup device by the moving speed of the image of the object to be inspected projected on the image pickup device. Since the control is performed at a speed slower than the speed at which the charges are transferred between the pixels, the position change between the object to be inspected and the image pickup device for each scan clock becomes small, and the image signal level change of the image pickup device becomes slow.

According to the present invention, the charge amount corresponding to the brightness of the object to be inspected is accumulated in each pixel, and the charges are sequentially transferred and integrated for each scan clock between these pixels, and the scan clock is repeated a predetermined number of times. An image pickup device that outputs the charges accumulated later as an image signal, a synchronization generation unit that generates a scan clock, an image signal that is output from the image pickup device in synchronization with the scan clock, and the image signal level and the threshold value Comparing means for detecting a change in the image signal level and the moving speed of the image of the object under inspection projected on the image pickup device is slower than the speed at which charges are transferred between pixels, and the object for each scan clock is A moving mechanism that controls the amount of movement between the inspection body and the image pickup device, a measurement unit that measures the image pickup position of the inspection target by the image pickup device, and a change in the image signal level by the comparison unit. When out is a position detecting apparatus and a position calculating means for reading the image pickup position of the device under test which is measured by the measuring means.

With such a position detecting device, the object to be inspected is picked up by the image pickup device, and the image signal output from the image pickup device is taken in by the comparison means in synchronization with the scan clock generated by the synchronization generation means. The change in the image signal level is detected by comparing the image signal level with the threshold value. At this time, the moving speed of the image of the object to be inspected projected on the imaging device is slower than the speed at which the charges are transferred between the pixels, and the moving mechanism changes the moving amount between the object to be inspected and the imaging device at each scan clock. Control. on the other hand,
The image pickup position of the object to be inspected by the image pickup device is measured by the measuring means, and when the change of the image signal level is detected by the comparing means, the image pickup position of the object to be inspected measured by the measuring means is read and used as an edge position, for example. .

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The position detecting method of the present invention relatively moves an object to be inspected such as a photomask and an imaging device, measures the imaging position of the photomask by the imaging device, and detects the object to be inspected when the image signal level of the imaging device changes. In the position detection method for reading the image pickup position of the image pickup device, the image pickup device accumulates the amount of electric charge according to the brightness of the photomask in each pixel, sequentially transfers the electric charge between these pixels, and integrates the accumulated electric charge to output an image signal. The area sensor is used, and the moving speed relative to the integrating area sensor and the photomask is set so that the moving speed of the image of the inspection object projected on the integrating area sensor is slower than the speed at which charges are transferred between pixels. To control.

More specifically, a photomask is provided for each scan clock so that the moving speed of the image of the object under inspection projected on the integrating area sensor is slower than the speed at which charges are transferred between pixels. Controls the amount of movement with the integrating area sensor.

FIG. 1 is a block diagram of a position detecting device using an integrating area sensor to which such a position detecting method is applied.
The photomask 2 is placed on the XY table 10.

An integrating area sensor 1 is arranged above the XY table 10, that is, above the photomask 2. As shown in FIG. 10, the integrating type area sensor 1 is configured by arranging M pixels in the vertical direction and N pixels in the horizontal direction, and accumulates each charge amount corresponding to the brightness of the photomask 2 in each pixel, Further, each charge accumulated in 1 to N pixels in the horizontal direction is sequentially transferred to 1 to N pixels adjacent in the horizontal direction for each scan clock, and the respective charge amounts are integrated.
After the scanning clock of one time, the respective charges accumulated in the horizontal direction of 1 to N pixels are output as an image signal.

FIG. 2 is a block diagram of the drive system of the integrating area sensor 1. A drive circuit 10 is connected to the integrating area sensor 1. The drive circuit 10 has three-phase vertical control signals φ _v1 , φ _v2 , φ _v3 for vertically transferring the electric charges of 1 to N pixels to the integrating area sensor 1.
Horizontal control signal φ for scanning 1 to N pixels in the horizontal direction
_It has a function of outputting _{H 2} and a scan clock φ _sc for outputting the accumulated charges as an image signal.

Vertical control signals φ _v1 , φ of the drive circuit 10
_A waveform shaping circuit 11 is connected between the output terminals of _v2 and _φv3 and the integrating area sensor 1. The waveform shaping circuit 11 has a driving circuit 10 as shown in FIGS. 3 (a) to 3 (d).
Vertical control signal phi _v1 outputted from, phi _v2, the waveform pulses p of phi _v3, waveform p ₁ was shaped into for example trapezoidal, rising and waveform p ₂ blunted falling edge, or these waveform p ₁ And a function of shaping the waveform p ₂ into a combined waveform p ₃ .

The specific configuration of the waveform shaping circuit 11 is as follows.
For example, as shown in FIG. 4 (a), the pin driver 12 is used to shape the waveform pulse p of the vertical control signals φ _v1 , φ _v2 , and φ _v3 into a trapezoidal waveform p ₁ , or the same figure ( b)
As shown in, the amplifier 13 and the capacitor C and the resistor C
Vertical control signals φ _v1 , φ _v2 , φ are connected in series with the R circuit.
rising waveform pulses p of _v3 and the waveform p ₂ blunted falling edge, or in which shaping the waveform p ₃ These combined waveform p ₁ and waveform p _2.

A preamplifier 14 is connected to the output terminal of the integrating area sensor 1, and an image signal is output through the preamplifier 14. Therefore, the drive circuit 10 outputs the three-phase vertical control signals φ _v1 , φ _v2 , φ _v3 , the horizontal control signal φ _H , and the scan clock φ _sc to the integrating area sensor 1 as shown in FIG. To do.

Of these, three-phase vertical control signals φ _v1 , φ _v2 ,
φ _v3 is shaped into a trapezoidal waveform pulse by passing through the waveform shaping circuit 11. Thus, the vertical control signal φ _v1 ,
φ _v2 , φ _v3 , horizontal control signal φ _H and scan clock φ
_{When sc} is sent to the integrating area sensor 1, in the integrating area sensor 1, the electric charges stored in 1 to N pixels in the horizontal direction are vertically adjacent by the vertical control signals φ _v1 , φ _v2 , and φ _v3. 1 to N pixels are sequentially transferred.

For example, as shown in FIG.
Paying attention to the _{1 to} a ₄ pixels, electric charges are stored in the pixel a ₁ because the vertical control signal φ _v1 is at the high level at time t ₁ .

Next, at time t ₂ , since the vertical control signals φ _v1 and φ _v2 both become high level, a part of the electric charge of the pixel a ₁ moves to the pixel a ₂ , and at the next time t _3, it becomes vertical. Since only the control signal φ _v2 becomes the high level, all the charges of the pixel a ₁ move to the pixel a ₂ .

Subsequently, at time t ₃ , only the vertical control signal φ _v2 becomes high level, so that charges are stored in the pixel a ₂ and at the next time t ₄ , the vertical control signals φ _v2 , φ _{v3 are generated.}
Become high level, a part of the electric charge of the pixel a ₂ moves to the pixel a ₃ , and at the next time t ₅ , the vertical control signal φ
Since only _v3 becomes high level, moves all charges of the pixels a ₂ to the pixel a _3.

Thereafter, the three-phase vertical control signals φ _v1 ,
Electric charges are sequentially transferred between the pixels a _{1 to} a _{4 in the} vertical direction according to the level changes of φ _v2 and φ _v3 . In this way, the waveform pulse p of the vertical synchronizing signals φ _v1 , φ _v2 , and φ _v3 is _generated as shown in FIGS. 3 (b) to (d).
By shaping the trapezoidal shape or the like as shown in, the charge applied to the well of the charge potential in each pixel changes gently without abrupt change, and the charge transfer efficiency increases.

Therefore, the integrating type area sensor 1 is shown in FIG.
As shown in FIG. 5, when the charges accumulated in the 1 to N pixels in the horizontal direction are sequentially transferred to the 1 to N pixels adjacent in the vertical direction and the respective charge amounts are integrated, M scan clocks φ _sc
The respective charges of 1 to N pixels, which are integrated later, are output as an image signal. This image signal is amplified and output by the preamplifier 14.

Although the above description is of the configuration of the integrating area sensor 1, FIG. 1 additionally shows the synchronization generating circuit 20 for generating the scan clock φ _sc . The comparison circuit 21 receives the scan clock φ _sc output from the synchronization generation circuit 20, receives the image signal output from the integrating area sensor 1 in synchronization with the scan clock φ _sc , and outputs the image signal level, that is, each image signal level. The brightness level of the pixel and a preset threshold value are compared for each pixel, and when the brightness level of the pixel is higher than the threshold value, the high level signal or the brightness level of the pixel is threshold. It has a function of outputting a low level signal when the value is lower than the value.

On the other hand, the movement control circuit 22 controls the movement of the XY table 10 on which the photomask 2 is placed in the XY directions. The movement speed of the XY table 10 is controlled by the photo projected on the integrating area sensor 1. It has a function of controlling the movement amount of the image of the mask 2 to be slower than the transfer speed of charges between pixels, that is, controlling the movement amount of the photomask 2 at each scan clock φ _sc to be small.

The laser length measuring system 23 measures the image pickup position of the photomask 2 by the integrating area sensor 1.
Actually, the XY table 10 is irradiated with laser light in the X and Y directions, respectively, and the reflected laser light is received to generate X.
The X and Y positions of the Y table 10 are detected, and the X and Y positions are detected.
It has a function of outputting the position as the imaging position of the photomask 2.

The latch circuit 24 receives the output signal of the comparison circuit 21, and when the output signal level is inverted from low level to high level or from high level to low level, is output from the laser length measurement system 23. It has a function of latching the imaging positions X and Y of the existing photomask 2 and passing them to the CPU 25.

The CPU 25 has a function of reading the image pickup positions X and Y of the photomask 2 latched by the latch circuit 24 as edge positions of the photomask 2.
Next, the operation of the apparatus configured as described above will be described.

The movement control circuit 22 controls movement of the XY table 10 in the XY directions, and scans the photomask 2 placed on the XY table 10 with respect to the integrating area sensor 1.

The moving speed of the XY table 10 at this time is the photomask 2 projected on the integrating area sensor 1.
The moving amount of the image is controlled at a speed lower than the speed at which charges are transferred between pixels, and the movement amount of the photomask 2 is controlled for each scan clock φ _sc .

The integrating area sensor 1 images the photomask 2 moving in the X direction or the Y direction from above and outputs an image signal. That is, the integration type area sensor 1 has a trapezoidal three-phase vertical control signal φ shown in FIG. 3, for example.
_{By v1} , φ _v2 , and φ _v3 , the electric charges stored in the 1 to N pixels in the horizontal direction shown in FIG. 10 are sequentially transferred to the 1 to N pixels adjacent to each other in the vertical direction, and the respective charge amounts are integrated, M times. After the scan clock φ _sc, the accumulated charges of 1 to N pixels in the horizontal direction are output as an image signal.

For example, as shown in FIG. 6A, when the integrating area sensor 1 is scanned with respect to a horizontal edge, the integrating area sensor 1 is arranged in the same direction as the edge direction of the horizontal edge, and the XY table 10 is arranged. Is moved to move the integrating area sensor 1 in a direction orthogonal to the horizontal edge direction.

Due to such movement, the integrating area sensor 1 outputs an image signal having a gradual level change as shown in FIGS. 7 (a) to 7 (c). That is, when the integrating area sensor 1 is moved from the light portion of the photomask 2 toward the dark portion, the image signal level output from the integrating area sensor 1 is in the bright portion of the photomask 2 of the integrating area sensor 1. 7 (a), the image signal level in the bright area is reached, when it is at the edge, it is lower than the image signal level in the bright area as shown in FIG. 7 (b), and when in the dark area.
As shown in (c), the image signal level changes to the dark area.

Particularly when the integrating area sensor 1 moves above the edge portion, the movement amount of the photomask 2 for each scan clock φ _sc is reduced by the movement control without position synchronization with respect to the XY table 10. The image signal level output from the integrating area sensor 1 is
It changes slowly as shown in FIG. The change in the image signal level is when the integrating area sensor 1 is scanned from the dark portion to the bright portion of the photomask, and the dotted line indicates
It shows a change in the image signal level when there is position synchronization, and it changes sharply.

When moving the integrating area sensor 1 with respect to the vertical edge as shown in FIG. 6B, the integrating area sensor 1 is arranged in a direction orthogonal to the edge direction of the vertical edge, and XY By moving the table 10, the integrating area sensor 1 is moved in a direction orthogonal to the vertical edge direction.

Due to such movement, the integrating area sensor 1 outputs an image signal having a level change as shown in FIGS. 9 (a) to 9 (c). That is, the integration type area sensor 1
Is moved from the light part of the photomask 2 to the dark part,
The image signal level output from the integrating area sensor 1 is such that when the integrating area sensor 1 is in the bright portion of the photomask 2, only the light portion image signal is applied to the bright portion as shown in FIG. When the level is reached and it is at the edge, the figure
As shown in (b), the image signal level has a bright portion and a dark portion corresponding to the position of the edge portion.
As shown in (c), the image signal level changes to have a bright portion and a dark portion corresponding to the position of the edge portion.

Thus, even when the integrating area sensor 1 moves above the vertical edge, the image signal level output from the integrating area sensor 1 changes slowly as shown in FIG.

The image signal thus output from the integrating area sensor 1 is sent to the comparison circuit 21. The comparison circuit 21 receives the scan clock φ _sc output from the synchronization generation circuit 20, and captures the image signal output from the integrating area sensor 1 in synchronization with the scan clock φ _sc .

The comparison circuit 21 compares the captured image signal level, that is, the brightness level of each pixel with a preset threshold value for each pixel, and the brightness level of the pixel is higher than the threshold value. High level signal when high,
A low level signal is output when the brightness level of the pixel is lower than the threshold value.

At this time, the integration type area sensor 1 controls the movement amount of the photomask 2 for each scan clock φ _sc by the movement control without position synchronization with respect to the XY table 10 and outputs from the integration type area sensor 1. Since the image signal level changes slowly as shown in FIG. 8, the timing at which the output level of the comparison circuit 21 is inverted corresponds to the position of the edge portion of the photomask 2, and the edge position should be detected with high accuracy. You can

On the other hand, the laser measuring system 23 irradiates the XY table 10 with laser light in the X and Y directions, respectively, and receives the reflected laser light to receive the X of the XY table 10.
And Y positions are detected, and these X and Y positions are output as the imaging position of the photomask 2.

Then, the latch circuit 24 is connected to the comparison circuit 21.
When the output signal level is inverted from the low level to the high level or from the high level to the low level, the image pickup positions X and Y of the photomask 2 output from the laser length measurement system 23 are input. Latch and pass to CPU25.

The CPU 25 reads the image pickup positions X and Y of the photomask 2 latched by the latch circuit 24 as the edge positions of the photomask 2. As described above, in the above-described embodiment, the image signal output from the integrating area sensor 1 is taken in by the comparison circuit 21 in synchronization with the scan clock φ _sc , and the image signal level is compared with the threshold value to obtain an image. A photomask 2 that detects a change in signal level and is projected on the integrating area sensor 1 at this time
The moving speed of the image is controlled to be slower than the speed at which the charge is transferred between the pixels, and the moving amount between the photomask 2 and the integrating area sensor 1 is controlled, and is measured by the laser length measuring system 23 when the image signal level is inverted. Since the image pickup position of the photomask 2 is read and used as the edge position, the image signal level of the integrating area sensor 1 changes slowly, and the position change amount for each scan clock φ _sc is reduced, so that the edge portion is changed. The position detection accuracy can be increased.

In addition, in the integrating area sensor 1, the waveform pulse p of the vertical synchronizing signals φ _v1 , φ _v2 , and φ _v3 is shown in FIG.
As shown in (b) to (d), a waveform p ₁ shaped like a trapezoid, a waveform p ₂ with blunt rising and falling edges, or a waveform p _{3 obtained} by combining these waveforms p ₁ and p ₂ Since the shaping is performed, the charge applied to the well of the charge potential in each pixel does not change abruptly but changes gently, that is, the rate of voltage change (skew) can be reduced, the charge transfer efficiency can be increased, and the sharpness can be improved. Image signals can be output.

The present invention is not limited to the above embodiment, but may be modified as follows. For example, the object to be inspected is not limited to the photomask 2, but can be applied to all the objects as long as they detect the position of the edge portion or the like.

[0057]

As described in detail above, claim 1 of the present invention,
According to the second aspect, it is possible to provide a position detection method capable of highly accurate position detection using the integrated area sensor. Further, according to claims 3 to 5 of the present invention, it is possible to provide a position detection device capable of highly accurate position detection using the integration area sensor.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a position detection device according to the present invention.

FIG. 2 is a configuration diagram of a drive system of an integrating area sensor.

FIG. 3 is a diagram showing a waveform shaping function in a drive system of an integrating area sensor.

FIG. 4 is a configuration diagram of a waveform shaping circuit in a drive system of the integrating area sensor.

FIG. 5 is a diagram showing a charge transfer action in the integrating area sensor.

FIG. 6 is a diagram showing a scanning direction with respect to an edge of an integrating area sensor.

FIG. 7 is a diagram showing a change in image signal level of the integrating area sensor with respect to a horizontal edge.

FIG. 8 is a diagram showing a change in image signal level of an integrating area sensor due to slow movement control.

FIG. 9 is a diagram showing a change in image signal level of the integrating area sensor with respect to a vertical edge.

FIG. 10 is a configuration diagram of an integrating area sensor.

FIG. 11 is a diagram showing scanning of a photomask by an integrating area sensor.

FIG. 12 is a diagram showing changes in the image signal level of the integrating area sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Accumulation type area sensor, 2 ... Photomask, 10 ... XY table, 20 ... Synchronous generation circuit, 21 ... Comparison circuit, 22 ... Movement control circuit, 23 ... Laser measuring system, 24 ... Latch circuit, 25 ... CPU.

Claims (5)

[Claims] 1. An object to be inspected and an imaging device are moved relative to each other, an imaging position of the object to be inspected by the imaging device is measured, and an image of the object to be inspected is captured when a level of an image signal of the imaging device changes. In a position detecting method for reading a position, the image pickup device accumulates a charge amount corresponding to the brightness of the object to be inspected in each pixel, sequentially transfers and integrates the charge between these pixels, and outputs an image signal. A position detecting method having a function, and controlling a moving speed of an image of the inspection object projected on the imaging device to be slower than a speed at which the electric charges are transferred between the pixels. 2. The image pickup device sequentially transfers and integrates the charges between the plurality of pixels for each scan clock, outputs the charges integrated after a predetermined number of scan clocks as an image signal, and The moving speed of the image of the inspection object projected on the imaging device is slower than the transfer speed of the electric charge between the pixels, and the movement amount between the inspection object and the imaging device at each scan clock is calculated. The position detecting method according to claim 1, wherein the position detecting method is controlled. 3. An object to be inspected and an imaging device are moved relative to each other, an imaging position of the object to be inspected by the imaging device is measured, and the object to be inspected is imaged when the image signal level of the imaging device changes. In a position detection device for reading a position, the imaging device has a function of accumulating an electric charge amount corresponding to the brightness of an object to be inspected in each pixel, sequentially transferring the electric charge between these pixels, integrating the electric charges, and outputting an image signal. And a moving speed of an image of the object under inspection projected on the imaging device is slower than a speed at which the charge is transferred between the pixels, and the object under inspection and the imaging device are relatively moved. A position detecting device comprising a moving mechanism for moving. 4. The image pickup device accumulates a charge amount corresponding to the brightness of an object to be inspected in each pixel, sequentially transfers and integrates the charge for each scan clock between these pixels, and repeats a predetermined number of times. The charge accumulated after the scan clock is output as an image signal, and the moving mechanism is configured such that the moving speed of the image of the object under inspection projected on the imaging device is slower than the speed at which the charge is transferred between the pixels. 5. The position detecting device according to claim 4, wherein the position detecting device has a function of controlling a movement amount of the object to be inspected and the image pickup device for each of the scan clocks. 5. An electric charge amount corresponding to the brightness of an object to be inspected is accumulated in each pixel, the electric charges are sequentially transferred and integrated for each scan clock between these pixels, and integrated after a predetermined number of scan clocks. An image pickup device for outputting the charged electric charges as an image signal, a synchronization generating unit for generating the scan clock, an image signal output from the image pickup device in synchronization with the scan clock, and the image signal level and threshold value. Comparing means for detecting a change in the image signal level by comparing the moving speed of the image of the object under inspection projected on the imaging device is slower than the speed at which the charge is transferred between the pixels, A moving mechanism that controls the amount of movement of the object to be inspected and the imaging device for each scan clock, and a meter that measures the imaging position of the object to be inspected by the imaging device. Means and the upon detection of the image signal level changes in accordance with the comparing means, said measuring means by a position detecting device being characterized in that includes a position calculating unit for reading the image capturing position of has been the object of inspection measurements.