JP3347490B2 - Positioning method, projection exposure apparatus and position deviation measuring apparatus by the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position measuring method performed in a semiconductor manufacturing apparatus, and more particularly, to an automatic alignment performed in a step-and-repeat type exposure apparatus (hereinafter, referred to as a stepper) as a position adjustment of a wafer. The present invention relates to a position measuring method used in the method.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram showing the configuration of a conventional exposure apparatus. A conventional stepper position measuring method will be described below with reference to FIG.

A wafer 1005 mounted on an XY stage 1007 via a wafer chuck 1006 receives illumination light from an exposure illuminating device 1001 which is formed into an exposure pattern by passing through a shutter 1002, a reticle 1003, and a projection exposure lens 1004. Irradiated.

An alignment mark (not shown) on a wafer 1005 mounted on an XY stage 1007 is illuminated by an alignment mark illumination device 1011 as a light source. This illumination light is reflected, and the reflected light is reflected by the alignment sensor 1.
At 012, light is received and photoelectric conversion is performed. As the alignment sensor 1012, an area sensor such as a CCD camera, a CCD line sensor, a photodiode, or the like is used.

[0005] The signal photoelectrically converted by the alignment sensor 1012 is A / D-converted by an A / D converter 1101 and stored as a plurality of pieces of digital pixel information in a storage device 1102 in the processing device. The stored pixel information is subjected to signal processing in an operation block 1103, the center of the alignment mark is obtained in a peak position detection block 1105 from the signal processing result, the position of the wafer is calculated, and sent to the stepper control device 1014. . When the position of the wafer is calculated, the stepper controller 1014 monitors the stage position with the interferometer 1009, and
08 was driven to open the shutter 1002 when the positions of the wafer 1005 and the reticle 1003 were correctly aligned, and the circuit pattern of the reticle 1003 was exposed on the wafer 1005.

The following method has been employed as the above signal processing method.

(1) The alignment mark taken from the CCD camera is projected in the long axis direction, and template matching is performed based on the obtained signal.

(2) The template matching is performed based on the signal of the alignment mark taken in by the line sensor.

In the template matching, the position of the highest correlation is detected as the center of the alignment mark by the correlation operation between the signal collected by the sensor and the template held in the processing device in advance. The template matching is represented by the following equation.

[0010]

(Equation 1) Here, S is a signal collected by the sensor, T is a template, and E is a correlation result. FIG. 10A shows the relationship between the signal S, the template T, and the correlation value E.

As a template, a correlation operation can be performed by folding the left half of the signal collected by the sensor.

[0012]

(Equation 2) Equation (2) has the advantage that template size and template information need not be defined. This is because the shape of the mark is symmetrical.

The mark center is the point where E (x) is at a maximum. In order to perform the calculation at a higher speed, the equation (2) is transformed into the equation (3).

[0014]

(Equation 3) In the case of the equation (3), the value becomes the minimum at the correlated position. Therefore, a position where the value becomes the minimum at the center of the symmetric mark may be found. The above operation is performed by the operation block 1103 described above.
In the method of Expression (1), the template T is stored in the template storage block 1104.

[0015]

As described above, in the conventional alignment method, a template matching process is performed on an alignment mark captured by a sensor.

However, the signal captured by the sensor changes due to the application of a resist to the alignment mark, and the signal width corresponding to the line width increases,
It becomes thin. For this reason, the template may not match the template that is held in advance, and the position having the highest correlation and the true center position may be shifted by 画素 pixel. If exposure is performed in such a state that the measurement accuracy is deteriorated, the exposure accuracy is deteriorated, and as a result, there is a problem that the yield of semiconductor production is reduced.

The cause of the above-mentioned displacement of 1/2 pixel will be described with reference to FIG. FIG. 10A shown earlier shows
The case where the size of the waveform S is the same as the template T at 2k + 1 points is shown. In this case, the correlation degree E has one peak. However, k is a natural number, and k = 11 in FIG.

FIG. 10B shows a case where the size of the waveform S 'is 2k + 2 points which is one point larger than the template T. In this case, the original peak position is the middle point between the two peak positions, but the peak of the correlation degree E 'appears at a position adjacent to two adjacent points. This is because in the conventional processing method,
This is because a slightly larger point among the points is determined as the mark center, and as a result, it is shifted by １ ／ pixel.

As a method of reducing the amount of 1/2 pixel shift, there is a method of increasing the pixel resolution. Improvement in pixel resolution can be realized by doubling the sampling frequency for A / D conversion and doubling the amount of memory. However, in this case, there is a problem that the scale of the hardware becomes large and the manufacturing cost becomes high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has realized a positioning method capable of improving measurement accuracy without increasing manufacturing costs. The purpose is to do.

[0021]

According to the positioning method of the present invention, a positioning mark provided on a predetermined object is two-dimensionally detected, template matching is performed, and the position of the predetermined object is confirmed. An alignment method, wherein a first correlation operation is performed using a template corresponding to the alignment mark to calculate a first correlation result, and a right half or a left half of a range in which the digital signal correlation operation is performed is determined. 1
A second correlation result is calculated by performing a second correlation operation using the template with a point shift, and a third correlation result is created by alternately combining the first correlation result and the second correlation result. , The center of the alignment mark is calculated from the third correlation result.

According to a second alignment method of the present invention, a first correlation result is calculated by performing a first correlation operation on a template corresponding to the alignment mark, and a right half or a left half of the template is calculated. A second template shifted by one point is created, a second correlation operation is performed with the digital signal of the alignment mark to calculate a second correlation result, and the first correlation result and the second correlation result are calculated. Are alternately combined to generate a third correlation result, and the center of the alignment mark is calculated from the third correlation result.

According to a third alignment method of the present invention, a half of the two-dimensionally detected alignment mark is regarded as a template, and a first folding correlation operation is performed with the other half of the digital signal to perform a first alignment calculation. A correlation result is calculated, a range in which the correlation calculation of the other half of the two-dimensionally detected alignment mark with the template is performed is shifted by one point, and a second loop-back correlation calculation is performed to obtain a second correlation result. Calculating, alternately combining the first correlation result and the second correlation result to create a third correlation result, and calculating a center of the alignment mark from the third correlation result. .

According to a fourth alignment method of the present invention, a half of the two-dimensionally detected alignment mark is regarded as a template, and a difference of a symmetrical position with respect to a digital signal of the other half is integrated. A first calculation result is calculated by performing a calculation, and a range in which the calculation between the template and the other half of the two-dimensionally detected alignment mark is performed is set to 1
Point shift and integration of the difference between symmetrical positions
To calculate a second operation result, alternately combine the first operation result and the second operation result to create a third operation result, and perform positioning from the third operation result. The center of the mark is calculated.

The image pickup means for picking up the alignment mark on the wafer surface and the alignment mark on the reticle surface according to the present invention, and the image pickup means for projecting and exposing the pattern on the reticle surface to the resist on the wafer surface. A projection exposure apparatus having an alignment mechanism for performing relative positioning of the reticle and the wafer using the obtained information, an imaging unit for imaging an alignment mark on the wafer surface, and a reticle surface on a resist on the wafer surface A projection exposure apparatus having an alignment mechanism for performing relative positioning between the reticle and the wafer using information obtained by the imaging means for projecting and exposing the upper pattern, and a position shift measurement mark on the wafer surface. It has an image pickup means for picking up an image, and detects the position of a position shift measurement mark using information obtained by the image pickup means to measure a shift amount. Also characterized by performing alignment using any of the methods described above in any of that positional deviation measuring device.

[0026]

In the positioning method of the present invention configured as described above, the following signal processing is specifically performed in order to eliminate the shift amount of 1/2 pixel without adding hardware. Will be

[0027]

(Equation 4) F is created by combining the operation results E1 and E2. Formula (6) shows the synthesis of F.

[0028]

(Equation 5) Equation (4) is a conventional correlation operation. Equation (5) is a correlation operation in which the position where the right half of the template acts is shifted by one pixel. By combining Equations (4) and (5), a correlation operation with half-pixel accuracy is realized.

[0029]

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

[0030] First Embodiment FIG. 1 is a block diagram showing a configuration of a first embodiment of an exposure apparatus according to the present invention.

With reference to FIG. 1, a description will be given of a method of capturing an alignment mark, a signal processing device, and a processing method in the present embodiment.

In this embodiment, a wafer 5 mounted on an XY stage 7 via a wafer chuck 6 has an exposure illuminating device 1 formed into an exposure pattern by passing through a shutter 2, a reticle 3 and a projection exposure lens 4. Illumination light.

The alignment mark (not shown) is provided on the wafer 5 mounted on the XY stage 7.
Light emitted from the alignment mark illuminating device 11, which is a light source, passes through the half mirror 10, the mirror 13, and the reduction type projection exposure lens 4, and illuminates the alignment mark. The image of the alignment mark generated by the illumination is reflected by the wafer 5, passes through the half mirror 10 along the same path as the incidence, and enters the alignment sensor 12. The alignment sensor 12 includes an area sensor such as a CCD camera, a CCD line sensor, a photodiode, and the like, and the image of the alignment mark received by the sensor is photoelectrically converted.

The alignment mark is, for example, a combination of two substances having different reflectivities as shown in FIG. 2, or a mark having unevenness even if it is the same reflector. is there. After the photoelectric conversion, a signal as shown in the right part of FIG. 2 is output.

The photoelectrically converted signal is processed by the alignment mark detection device 100. The alignment mark detection device 100 includes an A / D conversion device 101, a storage device 1
02, first operation block 103, second operation block 10
4, a template holding device 105 and a mark center detection block 106, the processing signal of which is output to the exposure device control device 14, and the exposure device control device 1
Reference numeral 4 controls the operation of the exposure apparatus according to the calculation result.

The signal photoelectrically converted by the alignment sensor 12 is converted into a digital signal by the A / D converter 101 and stored in the memory 102 in the alignment mark detector 100 as a plurality of pieces of digital pixel information.

When one of the photoelectrically converted information is enlarged,
The waveform S shown in FIG. Each dot in FIG. 3 indicates the sampled signal intensity. However, when an area sensor such as a CCD camera is used as the alignment sensor 12 and a detection signal from the area sensor is photoelectrically converted, the signal is a signal projected in the longitudinal direction of the mark.

The stored pixel information is subjected to signal processing in the first operation block 103 and the second operation block 104, respectively. The mark center detection block 106 calculates the center of the alignment mark based on the calculation result of each calculation block, and calculates the position of the wafer.

The method of calculating the wafer position in the mark center detection block 106 will be described with reference to FIG.

The first operation block 103 performs the following operation to calculate E1.

[0041]

(Equation 6) Since the template is left and right contrast,

[0042]

(Equation 7) Equation (7) is a correlation operation between the signal waveform and the template. The template need only be the mark edge portion. There are two reasons for this. The first reason is that the portion other than the edge does not have the mark information, and the second reason is to suppress the noise component in the area without the information from affecting the correlation calculation. Since the template is left-right contrast, it is summarized in equation (9). S, T, and E1 are shown on the left side of FIG.

The second operation block 104 performs the following operation to calculate E2.

[0044]

(Equation 8) S, T, and E2 are shown on the right side of FIG.

In the mark center detection block 106, F is created by combining the operation results E1 and E2 of each operation block. Formula (11) shows the synthesis of F.

[0046]

(Equation 9) The peak of F (x ₂ ) is the mark center position. E1 and E
2 is shown at the bottom of the figure.

When E1 and E2 are compared, the first term is the same. The second term covers the right template by one pixel outside. When x is arranged in the order of x-1, x, x + 1 for E1 and E2,

[0048]

(Equation 10) Referring to the above equations, it can be seen that E2 interpolates between E1. In the description with reference to FIG. 3, the template is applied to the outside of one pixel at the time of the correlation calculation of E2, but a similar result can be obtained by applying the template to the inside of one pixel. Of course, there are some modified examples of the calculation method, but the concept is the same.

When the position of the wafer is calculated by the mark center detection block 106, the exposure apparatus control unit 14
Drives the stage driving device 8 while monitoring the position of the XY stage 7 with the laser interference system 9, and when the position of the wafer 5 and the reticle 3 are accurately adjusted, the shutter 2
To expose the circuit pattern of the reticle 3 on the wafer 5.

The first operation block 103 described above,
The second operation block 104 and the mark center position detection block 106 can be realized by one general-purpose processor.

Second Embodiment As a second embodiment of the present invention, a first operation block 10
3. A method of implementing the correlation operation method by shifting the operation content template side of the second operation block 104 will be described. The process, the stage control, and the exposure method up to the photoelectric conversion of the alignment mark are the same as those in the first embodiment shown in FIG.

The first operation block 103 performs the following operation to calculate E1.

[0053]

[Equation 11] Equation (18) is the same as equation (9) in the first embodiment.

The second operation block 104 performs the following operation to calculate E2.

[0055]

(Equation 12) In the mark center detection block, F is created by combining the calculation results E1 and E2 of each calculation block. Formula (20) shows the synthesis of F.

[0056]

(Equation 13) The peak of F (x ₂ ) is the mark center position. When the operation results E1 and E2 of each operation block are compared, the first term is the same. The second term is shifted and shifted by one pixel in the right template. The right template is shifted inward by one pixel in the second embodiment because it corresponds to the first embodiment. As described in the first embodiment, a similar result can be obtained by shifting the right template outward by one pixel, and there are several variations of this equation, but the idea is the same.

In this embodiment, as in the first embodiment, the first operation block 103 and the second operation block 1
04 and the mark center position detection block 106 can be realized by one general-purpose processor.

Third Embodiment As a third embodiment of the present invention, the first operation block 10
3. A method of implementing the operation content of the second operation block 104 by the loopback correlation operation method will be described. The process, stage control, and exposure method up to photoelectric conversion of the alignment mark in the present embodiment are the same as those in the first embodiment, and a description thereof will be omitted.

When one of the photoelectrically converted signal waveforms is enlarged, a waveform S shown in FIG. 2 is obtained. Each dot indicates the signal intensity at which the dot was sampled. The left half of the signal waveform is a folded template. The template need only be the mark edge portion. There are two reasons for suppressing the influence of a noise component in a region having no mark information other than the edge and having no information on the correlation calculation. The correlation operation is shown in the following equation.

The first operation block 103 performs the following operation to calculate E1.

[0061]

[Equation 14] Equation (21) is a correlation operation in which the left half of the signal waveform (waveform S shown in FIG. 3) is regarded as a template. The template need only be the mark edge portion. There are two reasons. First, the portion other than the edge has no mark information, and second, it is to suppress the influence of the noise component in the region having no information on the correlation calculation.

The second operation block 104 performs the following operation to calculate E2.

[0063]

(Equation 15) In the mark center detection block 106, F is created by combining the calculation results E1 and E2 of each calculation block. Formula (23) shows the synthesis of F.

[0064]

(Equation 16) The peak of F (x ₂ ) is the mark center position.

In this embodiment, as in the first embodiment, the first operation block 103 and the second operation block 1
04 and the mark center position detection block 106 can be realized by one general-purpose processor.

Fourth Embodiment As a fourth embodiment of the present invention, the first operation block 10
3. A method of implementing the operation content of the second operation block 104 as a high-speed correlation operation method for performing the correlation operation in the second embodiment at high speed will be described. The process, stage control, and exposure method up to photoelectric conversion of the alignment mark in the present embodiment are the same as those in the first embodiment, and a description thereof will be omitted.

When one of the photoelectrically converted signal waveforms is enlarged, a waveform S shown in the figure is obtained. Each dot indicates the signal intensity at which the dot was sampled. The left half of the signal waveform is a folded template. The template need only be the mark edge portion. There are two reasons for suppressing the influence of a noise component in a region having no mark information other than the edge and having no information on the correlation calculation. The correlation operation is shown in the following equation.

[0068]

[Equation 17] Equations (24) and (25) integrate the difference between the signals at the folded symmetric positions. In the third embodiment, multiplication is used.
In a microprocessor or the like, the processing time for the subtraction is shorter. In the mark center detection block 106, F is created by combining the calculation results E1 and E2 of each calculation block. F
Formula (26) shows the synthesis of

[0069]

(Equation 18) However, in the mark center detection block 106, F
The minimum value of (x ₂ ) is searched, and that position is the mark center position. F (x ₂ ) is calculated by using the reciprocal F ′ (x ₂ )

[0070]

[Equation 19] Then, the mark center is obtained from the peak.

In this embodiment, as in the first embodiment, the first operation block 103 and the second operation block 1
04 and the mark center position detection block 106 can be realized by one general-purpose processor.

Fifth Embodiment FIG. 4 is a block diagram showing a configuration of an exposure apparatus according to a fifth embodiment of the present invention.

Referring to FIG. 4, description will be given of a method of taking in an alignment mark, a signal processing device, and a processing method in the present embodiment.

In the present embodiment, an alignment mark on a wafer is taken through a reticle.

This embodiment is different from the first embodiment shown in FIG. 1 in that the reticle 3
A reticle driving device 301 for driving the lens and a lens magnification driving device 305 for setting the magnification of the projection exposure lens 4 are provided, and the half mirror 10 and the mirror 1 in the first embodiment are provided.
3. A half mirror 302 and a mirror 3
00, an alignment mark illumination device 304 and an alignment sensor 303. The other configuration is the same as that of the first embodiment shown in FIG. 1, so the same reference numerals as those in FIG.

The alignment mark of the reticle 3 in this embodiment exists on the reticle 3 as a chrome pattern. On the wafer 5 mounted on the XY stage 7, alignment marks for the wafer are formed.

The alignment mark illumination device 30 as a light source
The light emitted from the light source 4 is reflected by the half mirror 302 and the mirror 30
The light passes through the reticle 3 and the reduction projection lens 4 to illuminate the alignment mark on the wafer 5. The image of the alignment mark is reflected by the wafer 5, follows the same path again, passes through the reticle 3, the half mirror 302, and enters the alignment sensor 303. This alignment mark image is
An area sensor such as a CCD camera or an alignment sensor 30 such as a CCD line sensor or a photodiode.
3 is photoelectrically converted.

The alignment mark of the reticle 3 is illuminated by the reflected light from the wafer 5. At the time of the illumination, the chrome pattern forming the alignment mark is configured to shield light, and the alignment sensor 303 forms a dark image. FIG. 5 shows an example of an image of the alignment mark taken by the CCD camera. FIG. 5 also shows a combined image of the left optical system (not shown).

The photoelectrically converted signal is supplied to the A / D converter 1
01 and is stored in the storage device 102 in the processing device as a plurality of pixel information.

When one of the photoelectrically converted information is enlarged, a waveform S shown in the figure is obtained. Each dot indicates the signal intensity at which the dot was sampled. However, when photoelectrically converted by an area sensor such as a CCD camera, it is a signal projected in the longitudinal direction of the mark.

In the storage device 102, the right and left X, Y
Marks (XL, YL, XR, YR) and a total of four signals are stored.

The stored four pieces of pixel information are independently stored in the first
Signal processing is performed in the operation block 103 and the second operation block 104, and the center of the alignment mark is obtained in the mark center detection block 106 based on the result of both operations. The calculation at this time is based on the center of the alignment mark of the wafer 5 (XLW).
C), the first reticle mark center (XLR1) and the second reticle mark center (XLR2) are detected. As described above, the wafer 5 and the reticle 3 are measured independently, and the relative positional shift amount is measured.

As a method of calculating the mark center position, any of the methods described in the first to fourth embodiments can be used.

When the relative displacement of each of the XL, YL, XR, and YR marks is measured, the exposure apparatus controller 14
The reticle position driving device 301 or the stage driving device 8 is driven while calculating the shift component, the rotation component, and the magnification component in the X and Y directions, and monitoring the position of the XY stage 7 with the interference system 9 to calculate the shift and rotation components. The correction is performed, and the rotation component is corrected by driving the wafer rotation device 6. The magnification component is corrected by driving the lens magnification driving device 305. When the positions of the wafer 5 and the reticle 3 are correctly adjusted, the shutter 2 is opened to expose the circuit pattern of the reticle 3 on the wafer 3.

Sixth Embodiment FIG. 6 is a block diagram showing the configuration of an exposure apparatus according to a sixth embodiment of the present invention.

Referring to FIG. 6, description will be given of a method of capturing an alignment mark, a signal processing apparatus and a processing method in the present embodiment.

In this embodiment, the light does not pass through the reduction projection lens.
An alignment mark on the wafer is collected using an external microscope.

In this embodiment, an off-axis microscope 401 is provided in the first embodiment shown in FIG. 1, and the half mirror 10, mirror 13, alignment mark illuminating device 11 and alignment sensor in the first embodiment are provided. 12 are each provided with a half mirror 403, a mirror 402, an alignment mark illumination device 405, and an alignment sensor 404.
It is what it was. The other configuration is the same as that of the first embodiment shown in FIG. 1, so the same reference numerals as those in FIG.

The wafer 5 mounted on the XY stage 7
An alignment mark for a wafer is formed thereon.

Positioning mark illumination device 40 as a light source
The light emitted from the light source 5 is reflected by the half mirror 403 and the mirror 40.
The light passes through a two-off-axis microscope 401 and illuminates an alignment mark on the wafer 5. The image of the alignment mark is reflected by the wafer 5, follows the same path again, and enters the alignment sensor 303. The image of the alignment mark is photoelectrically converted by an area sensor such as a CCD camera or an alignment sensor 404 such as a CCD line sensor or a photodiode.

As the method of calculating the mark center position, any of the methods described in the first to fourth embodiments can be used.

Seventh Embodiment FIG. 7 is a block diagram showing the configuration of a sixth embodiment of the exposure apparatus according to the present invention.

With reference to FIG. 7, a description will be given of a method for taking in an alignment mark, a signal processing device, and a processing method in the present embodiment.

In this embodiment, the method according to the present invention is applied to a displacement measuring device. The deviation amount measuring device is intended to measure a deviation amount measurement mark formed on a wafer surface after an exposure process is performed while a pattern on a reticle surface is aligned by an exposure device and a resist or the like is developed. A wafer 501 placed on a wafer chuck 502 on an XY stage 503 is irradiated with illumination light from a displacement amount measurement mark illumination device 505 via a half mirror 507 and a microscope 508. A deviation amount measurement mark as shown in FIG. 8 is formed on the upper surface of the wafer 501, and the image of the deviation amount measurement mark is reflected by the wafer 501, follows the same path again, passes through the half mirror 507, and has a CCD.
An area sensor such as a camera or two sets of X and Y CCDs
The light enters a shift amount observation imaging device 504 such as a line sensor or a photodiode and is photoelectrically converted.

The structure of the displacement amount detecting device 500 is the same as that of the first embodiment shown in FIG. The detection result of the alignment mark detection device 100 is output to the displacement amount measurement device control device 509, and the displacement amount measurement device control device 509 controls the XY stage 503 via the stage drive device 506 based on the detection result. Also. Output to the output device 510.

A description will be given of the shift amount detection performed in this embodiment.

In the image of the shift amount measurement mark shown in FIG. 8, the center of the outer mark (OUTM) and the center of the inner mark (INM) are set to a signal by any one of the first to fourth embodiments. X axis, Y from waveform XMEA, YMEA
The respective axes are obtained, and these differences are sent to the shift amount measuring device control device 509 and stored. The shift amount measuring device control device 509 controls the X through the stage driving device 506.
The Y stage 503 is driven to measure other misalignment amount measurement marks. Eventually, a statistic or the like is calculated and transferred to the output device 510 along with a plurality of stored measurement values,
Output.

[0098]

Since the present invention is configured as described above, it has the following effects.

In any of the first to fourth methods, detection can be performed with twice the accuracy as compared with the conventional method. Until now, the detection resolution has been reduced by half.
In some cases, the sampling frequency has to be doubled in order to achieve this, but the hardware must be relied upon. However, with this method, the accuracy can be doubled while inheriting the conventional hardware resources. Moreover, if the conventional processing method executes the operation block by software, the accuracy can be reduced to 2 by simply replacing the conventional software.
Can be doubled. It is a very cost-effective method of improving performance. In addition, since the alignment accuracy is insufficient, it can be easily introduced into a semiconductor manufacturing process where high-precision processing cannot be performed, and the processing accuracy can be doubled while using a conventional exposure apparatus.

The effects specific to the present invention described above are not limited to the semiconductor exposure apparatus according to any one of claims 5 to 12, but may be applied to claim 13
Also, the present invention can be used for detecting the position of a mark by a displacement inspection apparatus after exposure, as in the above-described embodiments. Also in this case, the measurement accuracy can be easily doubled.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a projection exposure apparatus in which first to fourth embodiments of the present invention are performed.

FIG. 2 is a diagram showing alignment marks that are photoelectrically converted by the projection exposure apparatus shown in FIG. 1 and signal waveforms.

FIG. 3 is a diagram for explaining a calculation method according to the present invention.

FIG. 4 is a diagram showing a configuration of a projection exposure apparatus according to a fifth embodiment of the present invention.

FIG. 5 is a diagram showing alignment marks imaged by a projection exposure apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a projection exposure apparatus according to a sixth embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a projection exposure apparatus according to a seventh embodiment of the present invention.

FIG. 8 is a diagram showing marks picked up by a shift amount measuring device according to a seventh embodiment of the present invention.

FIG. 9 is a view for explaining a conventional example of a projection exposure apparatus.

FIG. 10 is a diagram showing a problem of a conventional correlation operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Exposure illumination device 2 Shutter 3 Reticle 4 Projection exposure lens 5,501 Wafer 6,502 Wafer chuck 7,503 XY stage 8,506 Stage driving device 9 Laser interferometer 10,302,403,507 Half mirror 11,304,405 , 505 Alignment mark illumination device 12, 303, 404 Alignment sensor 13, 300, 402 Mirror 14 Exposure device control device 100, 200 Alignment mark detection device 101, 201 A / D conversion device 102, 202 Storage device 103 First operation Block 104 Second operation block 105 Template holding device 106, 206 Mark center detection block 301 Reticle driving device 401 Off-axis microscope 500 Misalignment amount detecting device 504 Misalignment amount observation and imaging device 508 Microscope 509 Deviation amount measuring device control device 510 Output device T Template S Signal of alignment mark E Correlation calculation result F Correlation calculation result after synthesis

Claims (16)

(57) [Claims] 1. A positioning method for two-dimensionally detecting an alignment mark provided on a predetermined object, performing template matching, and confirming the position of the predetermined object. A first correlation result is calculated by using the template, and a first correlation result is calculated. The right half or the left half of the range in which the correlation calculation of the digital signal is performed is shifted by one point, and the second correlation is performed by the template. Performing a calculation to calculate a second correlation result; alternately combining the first correlation result and the second correlation result to generate a third correlation result; and, based on the third correlation result, an alignment mark. Alignment mark detection method, wherein a center of the mark is calculated. 2. A positioning method for two-dimensionally detecting an alignment mark provided on a predetermined object, performing template matching, and confirming the position of the predetermined object. The first template
To calculate a first correlation result, create a second template in which the right half or the left half of the template is shifted by one point, and perform a second correlation operation with the digital signal of the alignment mark. Is performed to calculate a second correlation result. The first correlation result and the second correlation result are alternately combined to create a third correlation result, and a position of the alignment mark is calculated from the third correlation result. A method for detecting an alignment mark, comprising calculating a center. 3. A positioning method for two-dimensionally detecting an alignment mark provided on a predetermined object, performing template matching, and confirming the position of the predetermined object, wherein the two-dimensional detection is performed. Half of the aligned alignment mark is considered as a template and the first half
To calculate the first correlation result, and to shift the range for performing the correlation calculation of the other half of the two-dimensionally detected alignment mark with the template by one point to perform the second correlation calculation. Is performed to calculate a second correlation result. The first correlation result and the second correlation result are alternately combined to create a third correlation result, and a position of the alignment mark is calculated from the third correlation result. A method for detecting an alignment mark, comprising calculating a center. 4. A positioning method for two-dimensionally detecting an alignment mark provided on a predetermined object and performing template matching to confirm the position of the predetermined object, wherein the two-dimensional detection is performed. A half of the alignment mark thus determined is regarded as a template, a first operation for integrating a difference of a symmetrical position with the digital signal of the other half is performed to calculate a first operation result, and the template and the two-dimensional Calculating a second calculation result by shifting the range in which the calculation with the remaining half of the alignment mark detected in the first half is performed by one point, and integrating the difference between the symmetrical positions to calculate the second calculation result; And a second calculation result are alternately combined to generate a third calculation result, and a center of the alignment mark is calculated from the third calculation result. 5. An image pickup means for picking up an alignment mark on a wafer surface and an alignment mark on a reticle surface, and an image pickup means for projecting and exposing a pattern on the reticle surface to a resist on the wafer surface. A projection exposure apparatus comprising: an alignment mechanism for performing relative alignment between the reticle and the wafer using information obtained by performing a first correlation operation using a template corresponding to the alignment mark; A first calculation block that calculates the first correlation block, and shifts the right half or the left half of the range in which the correlation calculation of the signal imaged by the imaging unit is performed by one point to perform the second correlation calculation using the template. A second operation block for calculating a second correlation result, and a third correlation result is created by alternately combining the first correlation result and the second correlation result. And a mark center detection block for calculating the center of the alignment mark from the correlation result of (1). 6. An image pickup means for picking up an alignment mark on a wafer surface and an alignment mark on a reticle surface, and an image pickup means for projecting and exposing a pattern on the reticle surface to a resist on the wafer surface. A projection exposure apparatus comprising: an alignment mechanism for performing relative alignment between the reticle and the wafer using information to be obtained.
A first operation block for calculating a first correlation result by performing a correlation operation of: and a second template in which the right half or the left half of the template is shifted by one point, and a digital signal of the alignment mark is generated. A second correlation block for performing a second correlation calculation to calculate a second correlation result; alternately combining the first correlation result and the second correlation result to generate a third correlation result; A mark center detection block for calculating the center of the alignment mark from the third correlation result. 7. An image pickup means for picking up an alignment mark on a wafer surface and an alignment mark on a reticle surface, and an image pickup means for projecting and exposing a pattern on the reticle surface to a resist on the wafer surface. A projection exposure apparatus having an alignment mechanism for performing relative alignment between the reticle and the wafer using information obtained, wherein half of the alignment mark imaged by the imaging means is regarded as a template, and the other half of A first calculation block for calculating a first correlation result by performing a first loop-back correlation calculation with a signal; and a range in which a correlation calculation of the other half of the alignment mark imaged by the template and the imaging unit is performed by 1 A second operation block for calculating a second correlation result by performing a second loop-back correlation operation with a point shift; And a mark center detection block for generating a third correlation result by alternately combining the result and the second correlation result, and calculating a center of the alignment mark from the third correlation result. Exposure equipment. 8. An image pickup means for picking up an alignment mark on a wafer surface and an alignment mark on a reticle surface, and an image pickup means for projecting and exposing a pattern on the reticle surface to a resist on the wafer surface. A projection exposure apparatus having an alignment mechanism for performing relative positioning between the reticle and the wafer by using information obtained, wherein half of the alignment mark imaged by the imaging means is regarded as a template, and the other half is imaged. A first operation block for calculating a first operation result by performing a first operation for integrating a difference between symmetric positions with a signal imaged by the means, the template, and an image picked up by the image pickup means The range in which the calculation with the other half of the alignment mark is performed is shifted by one point, the second calculation for integrating the difference between the symmetric positions is performed, and the second calculation result is calculated. A second operation block to be output, and the first operation result and the second operation result are alternately combined to create a third operation result, and the center of the alignment mark is calculated from the third operation result. A projection exposure apparatus comprising a mark center detection block. 9. An image pickup means for picking up an alignment mark on a wafer surface, and said reticle and wafer using information obtained by said image pickup means for projecting and exposing a pattern on a reticle surface to a resist on the wafer surface. A projection exposure apparatus having an alignment mechanism for performing relative alignment of: a first arithmetic block for performing a first correlation operation using a template corresponding to the alignment mark to calculate a first correlation result; A second correlation operation of calculating a second correlation result by shifting the right half or the left half of the range in which the correlation operation of the signal imaged by the imaging means is performed by one point and performing the second correlation operation with the template; An arithmetic block, and the first correlation result and the second correlation result are alternately combined to create a third correlation result, and a third correlation result And a mark center detection block for calculating a center. 10. An image pickup means for picking up an alignment mark on a wafer surface, and said reticle and wafer using information obtained by said image pickup means for projecting and exposing a pattern on a reticle surface to a resist on the wafer surface. A projection exposure apparatus comprising: an alignment mechanism for performing relative alignment of: (1) a template corresponding to the alignment mark;
A first calculation block for calculating the first correlation result by performing the correlation calculation of the above, and a second template in which the right half or the left half of the template is shifted by one point, and the second template is captured by the imaging unit. A second operation block for performing a second correlation operation on the signal to calculate a second correlation result, and alternately combining the first correlation result and the second correlation result to generate a third correlation result And a mark center detecting block for calculating the center of the alignment mark from the third correlation result. 11. An image pickup means for picking up an alignment mark on a wafer surface, and said reticle and wafer using information obtained by said image pickup means for projecting and exposing a pattern on a reticle surface to a resist on the wafer surface. A projection exposure apparatus comprising: an alignment mechanism for performing relative alignment of: a half of the alignment mark imaged by the imaging means is regarded as a template, and a first folding correlation operation with the other half of the digital signal is performed. A first calculation block for calculating the first correlation result, and a second return correlation by shifting the range for performing the correlation calculation of the other half of the alignment mark imaged by the template and the imaging means by one point. A second operation block that performs an operation to calculate a second correlation result; and alternately combines the first correlation result and the second correlation result. And a mark center detection block for calculating a center of the alignment mark from the third correlation result. 12. An image pickup means for picking up an alignment mark on a wafer surface, and said reticle and wafer using information obtained by said image pickup means for projecting and exposing a pattern on a reticle surface to a resist on the wafer surface. A projection exposure apparatus having an alignment mechanism for performing relative positioning of the alignment mark, wherein half of the alignment mark imaged by the imaging unit is regarded as a template, and a signal of the other half is aligned with a signal imaged by the imaging unit. A first operation block for performing a first operation for integrating a difference between symmetrical positions to calculate a first operation result; an operation of the template and the other half of the alignment mark imaged by the imaging means A second operation block for shifting the range in which is performed by one point, performing a second operation for integrating the difference between symmetrical positions, and calculating a second operation result; A mark center detection block for generating a third operation result by alternately combining the first operation result and the second operation result, and calculating a center of the alignment mark from the third operation result. Characteristic projection exposure apparatus. 13. A position shift measuring device comprising an image pickup means for picking up an image of a position shift measurement mark on a wafer surface, detecting a position of the position shift measurement mark by using information obtained by the image pickup means, and measuring a shift amount. An apparatus, comprising: a first template corresponding to the misalignment measurement mark;
A first calculation block for calculating a first correlation result by performing a correlation calculation of the above, and shifting the right half or the left half of the range in which the correlation calculation of the signal imaged by the imaging means is performed by one point. A second operation block for performing a second correlation operation with the template to calculate a second correlation result; and alternately combining the first correlation result and the second correlation result to generate a third correlation result. And a mark center detection block for calculating the center of the alignment mark from the third correlation result. 14. An image pickup means for picking up an image of a position measurement mark on a wafer surface, and using the information obtained by the image pickup means to detect the position of the position measurement mark and measure the amount of displacement. An apparatus, comprising: a first operation block for performing a first correlation operation to calculate a first correlation result using a template corresponding to the displacement measurement mark; and shifting a right half or a left half of the template by one point. A second operation block for generating a second template, performing a second correlation operation on the signal imaged by the imaging unit and calculating a second correlation result, and And a mark center detection block for generating a third correlation result by alternately combining the two correlation results, and calculating the center of the position shift measurement mark from the third correlation result. Deviation measuring device. 15. A position shift measuring device comprising an image pickup means for picking up an image of a position shift measurement mark on a wafer surface, detecting a position of the position shift measurement mark using information obtained by the image pickup means, and measuring a shift amount. The apparatus, wherein a half of the displacement measurement mark imaged by the imaging means is regarded as a template, and a first return correlation operation is performed with a signal imaged by the other half of the position measurement mark to obtain a first correlation result. A first operation block for calculating the second return correlation operation by shifting the range for performing the correlation operation of the other half of the position shift measurement mark imaged by the template and the imaging means by one point, A second operation block for calculating a second correlation result; and a first correlation result and a second correlation result are alternately combined to form a third correlation result. A mark center detection block for calculating a center of a mark. 16. A position shift measuring device comprising an image pickup means for picking up an image of a position shift measurement mark on a wafer surface, detecting a position of the position shift measurement mark using information obtained by the image pickup means, and measuring a shift amount. The apparatus, wherein half of the position shift measurement mark imaged by the imaging unit is regarded as a template, and a first operation for integrating a difference of a symmetrical position with a signal imaged by the other half of the imaging unit is performed. A first calculation block for calculating the first calculation result by performing the calculation with the template and the remaining half of the position shift measurement mark imaged by the imaging means, by shifting the range by one point to a symmetric position A second operation block for calculating a second operation result by performing a second operation for integrating a difference between the first operation result and the second operation result, and synthesizing the third operation result by alternately combining the first operation result and the second operation result Create the second And a mark center detection block for calculating the center of the misalignment measurement mark from the calculation result of (3).