JPWO2004003469A1 - PATTERN DETECTION APPARATUS AND METHOD FOR USING THE SAME, MEASURING METHOD AND APPARATUS, POSITION MEASURING METHOD, EXPOSURE METHOD AND APPARATUS, AND DEVICE MANUFACTURING METHOD - Google Patents

Abstract

The main controller (20) irradiates the irradiation region near the alignment mark on the wafer with the first imaging light beam in the first state where the positional relationship between the wafer W and the alignment sensor (14) is in a predetermined state. Then, after adjusting the Z position of the wafer based on the reflected light of the imaging light beam from the wafer surface, the XY position information of the mark is detected. Next, in the second state where the wafer is rotated 180 ° from the first state, the irradiation region is irradiated with the second imaging light beam, and the Z position of the wafer is based on the reflected light from the wafer surface of the imaging light beam. After adjusting the XY position information of the mark is detected. In this case, since each imaging light beam is irradiated to the same irradiation region, the focus state before the rotation after the wafer rotation can be accurately reproduced. By using the position information obtained in this way, it is possible to accurately calculate the detection deviation caused by the detection system and the detection deviation caused by the mark formation state.

Description

  The present invention relates to a pattern detection apparatus and a method of using the same, a measurement method and apparatus, a position measurement method, an exposure method and apparatus, and a device manufacturing method. More specifically, the present invention optically detects a pattern formed on an object. Pattern detection apparatus and method of use thereof, measurement method and apparatus for measuring at least one of detection deviation caused by detection system and detection deviation caused by formation state of measurement target pattern, position measurement method including the measurement method, and position measurement The present invention relates to an exposure method using a method, an exposure apparatus including the pattern detection apparatus, and a device manufacturing method using the exposure method or the exposure apparatus.

Conventionally, in a lithography process for manufacturing a semiconductor element, a liquid crystal display element, etc., a photosensitive agent such as a resist is applied to a pattern formed on a mask or a reticle (hereinafter, collectively referred to as “reticle”) through a projection optical system. 2. Description of the Related Art Exposure apparatuses that transfer onto a coated wafer or a substrate such as a glass plate (hereinafter referred to as “wafer” as appropriate) are used. As such an exposure apparatus, a static exposure type projection exposure apparatus such as a so-called stepper and a scanning exposure type projection exposure apparatus such as a so-called scanning stepper (also called a scanner) are mainly used. In such an exposure apparatus, it is necessary to perform alignment (alignment) between the reticle and the wafer with high accuracy prior to exposure. The demand for this alignment accuracy has become stricter with the miniaturization of patterns, and various devices have been made for alignment.
In order to perform the above alignment with high accuracy, it is necessary to detect the position of the reticle and the position of the wafer with high accuracy. For example, the position of the reticle is generally detected using exposure light. The reticle alignment mark formed on the reticle is irradiated with the exposure light, and image processing is performed on the reticle alignment mark image data captured by a CCD camera or the like. Then, a VRA (Visual Reticle Alignment) type reticle alignment microscope that measures the mark position is used. On the other hand, for detecting the position of the wafer, an FIA (Field that measures the mark position by illuminating with light having a wide wavelength bandwidth using a halogen lamp or the like and processing image data of an alignment mark imaged by a CCD camera or the like. An Image Alignment) type alignment sensor or the like is used.
In aligning a reticle and a wafer using these optical alignment sensors, first, alignment marks on the reticle are detected and processed, and position coordinates are measured. Next, the alignment mark on the wafer is detected and processed, and the position coordinates are measured to obtain the position of the shot to be overlaid. Based on those results, the wafer is moved by the wafer stage so that the reticle pattern image overlaps the shot position, and the reticle pattern image is transferred onto the wafer via the projection optical system.
However, the position measurement result may deviate from the true mark position depending on the state of the optical system constituting the above-described position measurement apparatus (wavefront aberration, displacement of the aperture position, etc.). Further, if the observed alignment mark itself is not formed as designed, the position measurement result will be lost.
It is an asymmetric component in the measurement axis direction that contributes to the positional deviation due to the deformation of the mark on the wafer. Therefore, a state in which the wafer faces a certain direction (hereinafter referred to as “0 ° state” for convenience) and a state in which the wafer is rotated 180 ° from this state (hereinafter referred to as “180 ° state” for convenience). If the same mark is measured in both states, the sign of the amount of misalignment (WIS: Wafer Induced Shift) resulting from wafer deformation (mark deformation on the wafer) is inverted.
On the other hand, the position displacement component (TIS: Tool Induced Shift) caused by the position measurement apparatus is constant regardless of the wafer direction, and therefore the contribution to the position displacement amount at the time of wafer reversal is different from that in the above WIS.
Therefore, by measuring the same mark on the wafer at 0 ° and 180 °, and combining the position measurement results, the positional deviation amount (TIS) caused by the apparatus can be known.
However, TIS and WIS generally depend on the focus state of the mark to be detected, that is, the amount of positional deviation in the optical axis direction of the mark with respect to the imaging plane of the optical system of the position measuring device when measuring the mark (position). Therefore, when measuring the TIS (or WIS), it is important to reproduce the same focus state as the 0 ° state when the wafer is turned 180 °.
By the way, in the above-described FIA system or the like, in order to perform focus measurement, the reflected light beam from the wafer surface of the slit image projected on the wafer is divided into two on the pupil plane, and each divided light beam is slit on the imaging surface. The image is re-imaged, the change (positional deviation) in the distance (interval) between the slit images on the imaging surface is detected, and the focus state is detected based on the detection result, that is, the focus state (defocused) In general, a focus measurement system that detects (amount) as a change in the distance between slit images is incorporated.
However, in the conventional TIS measurement, after the measurement in the 0 ° state is completed, the wafer is rotated by 180 °, and the focus measurement is performed using the focus measurement system in the state, and then the focus is determined based on the measurement result. The position of the mark was measured by adjusting the state. For this reason, after the reversal, the position at which the slit image is projected onto the wafer changes, and the light beam is affected by the pattern or mark existing on the wafer, so that the focus measurement in the state of 0 ° and the slit image are performed. Often, the effects of the luminous flux of the light were different. In such a case, an offset is included in the focus measurement value due to a difference in the influence of the light flux of the slit image, and even if the focus state is adjusted based on the focus measurement value, a focus adjustment error corresponding to the offset inevitably occurs. It happened. As a result, an error is included in the TIS measurement result, and as a result, an error occurs in the mark position measurement performed in consideration of the measurement result of the TIS.
The present invention has been made under such circumstances, and a first object of the present invention is to provide a pattern detection apparatus that can accurately reproduce the focus state before inversion after inversion of an object on which a pattern to be detected is formed. It is to provide.
The second object of the present invention is to provide a method of using a pattern detection apparatus capable of accurately reproducing the focus state before inversion after the object on which the pattern to be detected is formed and accurately obtaining the position information of the pattern. It is to provide.
A third object of the present invention is to provide a measurement method capable of accurately measuring at least one of a detection deviation caused by a detection system and a detection deviation caused by a formation state of a measurement target pattern.
A fourth object of the present invention is to provide a position measurement method capable of accurately obtaining position information of an object.
A fifth object of the present invention is to provide an exposure method and an exposure apparatus that can form a pattern on an object with high accuracy.
A sixth object of the present invention is to provide a device manufacturing method capable of improving device productivity.

From a first viewpoint, the present invention is a pattern detection apparatus for optically detecting a pattern formed on an object, wherein a detection area is set at a predetermined point on the object, and the pattern of the detection area is set. A detection system that optically detects via a detection optical system; and is coupled to at least one set of irradiation regions that are rotationally symmetric with respect to the detection region on the object and extend in a direction away from the detection region, respectively. An irradiation system capable of irradiating an image light beam, and an optical axis direction of the detection optical system in the irradiation area where the reflected light from the object surface of any one of the imaged light beams is photoelectrically detected and irradiated with the image light beam A focus position detection device having a light receiving system that outputs a photoelectric conversion signal according to the position of the object surface.
According to this, the focus position detecting device can irradiate the imaging light flux respectively on at least one set of irradiation areas that are rotationally symmetric with respect to the detection area on the object and extend in a direction away from the detection area. Has an irradiation system. For this reason, an image forming light beam is irradiated from the irradiation system onto a certain area on the object (referred to as “first irradiation area” for convenience), and the reflected light from the object surface of the image forming light beam is converted into a photoelectric conversion signal by the light receiving system. Based on the detection result, the position in the optical axis direction of the object surface is detected, and the position in the optical axis direction of the object is adjusted based on the detection result. ) In the state after the inversion of the object, the first irradiation area on the object coincides with the irradiation area (referred to as a “second irradiation area” for convenience) that forms a pair with the first irradiation area before the inversion. ing. Therefore, after the object is inverted, the second irradiation area on the object before the inversion (that is, the first irradiation area on the object after the inversion) is irradiated with the imaging light beam, and the imaging light beam is reflected from the object surface. By detecting the optical axis position of the object surface based on the photoelectric conversion signal from the light receiving system and adjusting the optical axis position of the object based on the detection result, the same focus state as before the inversion can be accurately reproduced. Is done. Therefore, according to the pattern detection apparatus of the present invention, it is possible to accurately reproduce the focus state before inversion after the inversion of the object on which the detection target pattern is formed.
In this case, the irradiation system may be capable of irradiating the image forming light beams to two sets of irradiation regions that are rotationally symmetric with respect to the predetermined point with respect to the two orthogonal axes.
From a second aspect, the present invention is a method of using the pattern detection apparatus of the present invention, wherein the positional relationship between the object on which the measurement target pattern is formed and the detection optical system is in a predetermined state. In a state, a first imaging light beam is irradiated from the irradiation system constituting the focal position detection device to a predetermined irradiation region in the vicinity of the measurement target pattern on the object, and the photoelectric conversion signal output from the light receiving system Adjusting the position of the object surface with respect to the optical axis direction of the detection optical system based on the position of the object surface with respect to the optical axis direction of the detection optical system adjusted using the detection system. Optically detecting a measurement target pattern and obtaining first in-plane position information in a plane perpendicular to the optical axis of the measurement target pattern; and detecting the object from the first state to the detection optical system; Relatively 180 ° times In the second state, the irradiation region is irradiated with a second imaging light beam different from the first imaging light beam from the irradiation system, and the detection is performed based on a photoelectric conversion signal output from the light receiving system. Adjusting the position of the object surface with respect to the optical axis direction of the optical system; optically detecting the measurement target pattern using the detection system with the optical axis direction position of the object surface adjusted; Obtaining a second in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern.
According to this, in the first state where the positional relationship between the object and the detection optical system is in a predetermined state, from the irradiation system constituting the focal position detection device in the predetermined irradiation region near the measurement target pattern on the object The position of the object surface with respect to the optical axis direction of the detection optical system is adjusted based on the photoelectric conversion signal from the light receiving system that irradiates the first imaging light beam and photoelectrically detects the reflected light from the object surface of the imaging light beam. . With this adjustment made (the positional relationship between the object and the detection optical system in the plane perpendicular to the optical axis is the same as in the first state), the measurement target pattern is optically detected using the detection system. Then, first in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern is obtained. Next, the irradiation in which the first imaging light beam is irradiated in a state where the object is rotated by 180 ° relative to the detection optical system from the first state (more precisely, the above-described adjusted state). A region is irradiated with a second imaging light beam different from the first imaging light beam from the irradiation system, and reflected light from the object surface of the imaging light beam is detected based on a photoelectric conversion signal from a light receiving system. The position of the object surface with respect to the optical axis direction of the optical system is adjusted, and this adjustment is made (the positional relationship between the object and the detection optical system in the plane perpendicular to the optical axis is the same as in the second state) Thus, the measurement target pattern is optically detected using the detection system, and second in-plane position information in the plane orthogonal to the optical axis of the measurement target pattern is obtained. Accordingly, it is possible to accurately obtain the position information of the pattern by accurately reproducing the focus state before the inversion after the object on which the pattern to be detected is formed.
In this case, the method further includes a step of calculating at least one of a detection deviation caused by a detection system and a detection deviation caused by the formation state of the measurement target pattern using the first and second in-plane position information. It can be.
From a third aspect, the present invention is a position measurement method for measuring the position of an object using the pattern detection apparatus of the present invention, and the positional relationship between the object on which the measurement target pattern is formed and the detection optical system In a first state where the first imaging light beam is irradiated from the irradiation system constituting the focal position detection device to a predetermined irradiation region in the vicinity of the measurement target pattern on the object, Adjusting the position of the object surface opened in the optical axis direction of the detection optical system based on a photoelectric conversion signal output from the system; and adjusting the position of the object surface with respect to the optical axis direction of the detection optical system In a state where the measurement target pattern is optically detected using the detection system to obtain first in-plane position information in a plane perpendicular to the optical axis of the measurement target pattern;
In a second state in which the object is rotated from the first state by 180 ° relative to the detection optical system, a second different from the first imaging light flux from the irradiation system to the irradiation region. Irradiating an imaging light beam and adjusting the position of the object surface relative to the optical axis direction of the detection optical system based on a photoelectric conversion signal output from the light receiving system; and adjusting the position of the object surface in the optical axis direction In a state where the measurement target pattern is optically detected using the detection system to obtain second in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern; Calculating at least one of a detection deviation caused by a detection system and a detection deviation caused by the formation state of the measurement target pattern using the second in-plane position information; and the first in-plane position information and the second One of the in-plane position information and the calculation Calculating a position of the object based on the detected shift that; a first position measuring method comprising.
That is, the first position measurement method of the present invention uses each step of the above-described use method of the present invention and the first and second in-plane position information obtained during the execution of the use method. Calculating at least one of a detection deviation (TIS) due to the detection deviation and a detection deviation (WIS) due to the formation state of the measurement target pattern, one of the first in-plane position information and the second in-plane position information, Calculating the position of the object based on the calculated detection deviation. Therefore, according to the first position measurement method of the present invention, the first in-plane position information, the second in-plane position information, the detection deviation caused by the detection system, and the measurement are not affected by the inversion of the object. At least one of the detection deviations caused by the formation state of the target pattern can be obtained with high accuracy, and one of the first in-plane position information and the second in-plane position information obtained with high accuracy and the calculated detection deviation. By calculating the position of the object based on the above, it is possible to obtain the position information of the object with high accuracy without being affected by the detection deviation.
According to a fourth aspect of the present invention, there is provided an exposure method for exposing a photosensitive object with an energy beam to form a predetermined pattern on the object, wherein the object is measured by the first position measuring method of the present invention. A first exposure method comprising: a step of measuring a position; and a step of exposing the object with the energy beam while controlling the position of the object based on the measured position information.
According to this, the object is exposed by the energy beam while controlling the position of the object based on the position information of the object accurately obtained by the first position measuring method of the present invention. That is, exposure is performed while controlling the position of the object with high accuracy. Therefore, the pattern can be formed on the object with high accuracy.
According to a fifth aspect of the present invention, in the first state where the positional relationship between the object on which the measurement target pattern is formed and the detection optical system is in a predetermined state, the predetermined vicinity of the measurement target pattern on the object is determined. The object relating to the optical axis direction of the detection optical system in the irradiation region is obtained by irradiating the irradiation region with an imaging light beam and photoelectrically detecting the reflected light from the object surface of the imaging light beam through the detection optical system. Obtaining the first position information of the surface; and adjusting the position of the object surface in the optical axis direction based on the first position information, and using the detection system including the detection optical system, the measurement target pattern A first detection step of obtaining first in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern; and detecting the object from the first state to the detection optical system Relatively 180 degrees rotated In this state, the imaging region is irradiated with an imaging light beam, and reflected light from the object surface of the imaging light beam is photoelectrically detected, and the object surface relative to the optical axis direction of the detection optical system in the irradiation region is detected. 2) obtaining the position information; optically detecting the measurement target pattern using the detection system in a state in which the position of the object surface in the optical axis direction is adjusted based on the second position information; A second detection step of obtaining second in-plane position information in a plane perpendicular to the optical axis of the first detection position; and a detection deviation caused by the detection system and the measurement object using the first and second in-plane position information. Calculating at least one of detection deviations caused by a pattern formation state.
According to this, in the first state, the focus of the object is based on the first position information regarding the optical axis direction of the object surface obtained by irradiating the image forming light beam to the irradiation area near the measurement target pattern. With the state adjusted, a measurement target pattern is detected, and first in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern is obtained. In this case, since the first in-plane position information can be obtained without defocusing, the first in-plane position information can be obtained with high accuracy. Even in the second state in which the object is rotated by 180 ° relative to the detection optical system from the first state, an image is formed on the same irradiation region as the region irradiated with the imaging light beam in the first state. The light beam is irradiated, and the focus state of the object is adjusted based on the second position information regarding the optical axis direction of the object obtained by the irradiation. In this case, since the same region is irradiated with the imaging light beam in the first state and the second state, the object is rotated 180 ° relative to the detection optical system from the first state. When adjusting the focus state, the focus state before rotation is accurately reproduced. Then, by detecting the measurement target pattern in a state in which this focus state is accurately reproduced, second in-plane position information in the plane orthogonal to the optical axis of the measurement target pattern is obtained. Also in this case, since the second in-plane position information can be obtained without defocusing, the second in-plane position information can be obtained with high accuracy.
Then, using the first and second in-plane position information obtained in this manner, at least one of a detection deviation caused by the detection system and a detection deviation caused by the formation state of the measurement target pattern is calculated. Therefore, according to the present invention, it is possible to accurately measure at least one of the detection deviation caused by the detection system and the detection deviation caused by the formation state of the measurement target pattern without being affected by the inversion of the object with respect to the detection optical system. Can do.
In this case, in the first state, the imaging light beam is irradiated in the second state almost in the same region as the predetermined irradiation region on the object irradiated with the imaging light beam. In addition, the method may further include a step of moving the object in a plane orthogonal to the optical axis after the first detection step and before the second detection step.
In the first measurement method of the present invention, when a plurality of imaging light beams can be irradiated on the object, the predetermined irradiation on the object irradiated with the imaging light beam in the first state. In the first detection step and the second detection step, the image forming light beam irradiated on the object is irradiated so that the image forming light beam is irradiated onto the substantially same region as that in the second state. It can be used by switching.
From a sixth viewpoint, the present invention is a position measurement method for measuring the position of an object, and is a first state in which the positional relationship between the object on which the measurement target pattern is formed and the detection optical system is in a predetermined state. And irradiating a predetermined irradiation area on the object in the vicinity of the measurement target pattern with an imaging light beam, photoelectrically detecting reflected light from the object surface of the imaging light beam through the detection optical system, and Obtaining the first position information of the object surface with respect to the optical axis direction of the detection optical system in the irradiation region; and adjusting the position of the object surface with respect to the optical axis direction based on the first position information; A first detection step of optically detecting the measurement target pattern using a detection system including a detection optical system to obtain first in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern; From the first state to the The irradiation region is irradiated with an imaging light beam in a second state rotated by 180 ° relative to the exit optical system, and reflected light from the object surface of the imaging light beam is photoelectrically detected to detect the irradiation region. Obtaining the second position information of the object surface with respect to the optical axis direction of the detection optical system in the above; using the detection system in a state where the position of the object surface in the optical axis direction is adjusted based on the second position information A second detection step of optically detecting the measurement target pattern and obtaining second in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern; and the first and second in-plane position information. And calculating at least one of detection deviation caused by the detection system and detection deviation caused by the formation state of the measurement target pattern; one of the first in-plane position information and the second in-plane position information And the calculated detection deviation Calculating a position of the object based on the second position measuring method. That is, the second position measurement method is based on each step of the first measurement method, one of the first in-plane position information and the second in-plane position information, and the calculated detection deviation. And calculating the position of the object.
Therefore, according to the second position measuring method of the present invention, the first position measuring method of the present invention is not affected by the inversion of the object, and the first in-plane position information, the second in-plane position information, In addition, at least one of detection deviation (TIS) caused by the detection system and detection deviation (WIS) caused by the formation state of the measurement target pattern can be obtained with high accuracy. Then, by calculating the position of the object based on one of the first in-plane position information and the second in-plane position information obtained with high accuracy and the calculated detection deviation, it is affected by the detection deviation. Therefore, the position information of the object can be obtained with high accuracy.
According to a seventh aspect of the present invention, there is provided an exposure method for exposing a photosensitive object with an energy beam to form a predetermined pattern on the object, wherein the object is obtained by the second position measurement method of the present invention. A step of measuring the position of the object, and a step of exposing the object with the energy beam while controlling the position of the object based on the measured position information.
According to this, the object is exposed by the energy beam while controlling the position of the object based on the position information of the object accurately obtained by the second position measurement method of the present invention. That is, exposure is performed while controlling the position of the object with high accuracy. Therefore, the pattern can be formed on the object with high accuracy.
According to an eighth aspect of the present invention, a detection system that sets a detection region at a predetermined point on an object and optically detects a pattern of the detection region via a detection optical system;
An irradiation system capable of irradiating at least one set of irradiation regions, each of which is rotationally symmetric with respect to the detection region on the object and extending in a direction away from the detection region; A light receiving system for photoelectrically detecting reflected light from the object surface and outputting a photoelectric conversion signal corresponding to the position of the object surface with respect to the optical axis direction of the detection optical system in the irradiation region irradiated with the imaging light beam; A focus position detection device having: a first drive mechanism for driving the object in at least the optical axis direction; and relatively rotating the object and the detection optical system around an axis in the optical axis direction by at least 180 ° The focal position detection device is configured in an irradiation region in the vicinity of the measurement target pattern on the object in a first state in which the positional relationship between the object and the detection optical system is in a predetermined state. The first imaging light beam is irradiated from the irradiation system and the reflected light from the object surface of the imaging light beam is received through the first drive mechanism based on the photoelectric conversion signal output from the light receiving system. The position of the object surface in the optical axis direction is adjusted, and in the state after the adjustment, the measurement target pattern is optically detected using the detection system, and is orthogonal to the optical axis of the measurement target pattern. A first detection control system for detecting first in-plane position information in the plane;
In the second state in which the object is rotated by 180 ° relative to the detection optical system from the first state via the second driving mechanism, the first connection is made from the irradiation system to the irradiation region. A second imaging light beam different from the image light beam is irradiated, and a reflected light from the object surface of the imaging light beam is received, and a photoelectric conversion signal output from the light receiving system is received via the first drive mechanism. Adjusting the position of the object surface with respect to the optical axis direction and, in the state after the adjustment, using the detection system, second in-plane position information in a plane perpendicular to the optical axis of the measurement target pattern is obtained. Calculating at least one of a detection deviation caused by the detection system and a detection deviation caused by the formation state of the measurement target pattern, using the second detection control system to be detected; and the first and second in-plane position information. A first meter comprising: a calculation device; It is a device.
According to this, in the first state where the positional relationship between the object and the detection optical system is in a predetermined state, the focus position detection device is applied to the irradiation region in the vicinity of the measurement target pattern on the object. The object surface is irradiated via the first drive mechanism on the basis of the photoelectric conversion signal output from the light receiving system that receives the reflected light from the object surface of the imaged light beam. In the first surface in the plane perpendicular to the optical axis of the measurement target pattern, the position of the measurement target pattern is adjusted and the measurement target pattern is optically detected using the detection system in the adjusted state. Detect location information. For this reason, since the first in-plane position information can be obtained without defocusing, the first in-plane position information can be obtained with high accuracy.
Further, in the second detection control system, the object is moved from the irradiation system to the irradiation area in the second state in which the object is rotated by 180 ° relative to the detection optical system from the first state via the second drive mechanism. A second imaging light beam different from the first imaging light beam is irradiated, and a reflected light from the object surface of the imaging light beam is received through a first drive mechanism based on a photoelectric conversion signal output from a light receiving system. Then, the position of the object surface in the optical axis direction is adjusted, and in the state after the adjustment, second in-plane position information in the plane orthogonal to the optical axis of the measurement target pattern is detected using the detection system. In this case, since the first imaging light beam and the second imaging light beam are irradiated on the same region in the first state and the second state, the object is moved from the first state to the detection optical system. When the focus state is adjusted after a relative rotation of 180 °, the focus state before the rotation is accurately reproduced. Then, the position information in the second plane in the plane orthogonal to the optical axis of the measurement target pattern can be obtained in a state where this focus state is accurately reproduced and in the absence of defocus. Location information can be obtained.
Then, the calculation device calculates at least one of the detection deviation caused by the detection system and the detection deviation caused by the formation state of the measurement target pattern using the first and second in-plane position information obtained in this way. To do. Therefore, according to the present invention, it is possible to accurately measure at least one of the detection deviation caused by the detection system and the detection deviation caused by the formation state of the measurement target pattern without being affected by the inversion of the object with respect to the detection optical system. Can do.
According to a ninth aspect of the present invention, there is provided an exposure apparatus that exposes a photosensitive object with an energy beam to form a predetermined pattern on the object, and detects a position of a mark formed on the object. A mark position detection system; and a control device that controls the position of the previous object based on a detection result of the mark position detection system, wherein the mark position detection system includes the first measurement device of the present invention. It is the 1st exposure apparatus characterized.
According to this, since the mark position detection system includes the first measurement apparatus of the present invention, the detection deviation (TIS) caused by the detection system and the detection deviation (WIS) caused by the formation state of the measurement target pattern. ) Can be measured with high accuracy, and when detecting the position of the mark formed on the object, it is possible to detect the mark position with high accuracy in consideration of the detection deviation measured with high accuracy. . Then, at the time of exposure, the position of the object is controlled by the control device based on the detection result of the mark position detection system. That is, exposure is performed while controlling the position of the object with high accuracy. Therefore, the pattern can be formed on the object with high accuracy.
According to a tenth aspect of the present invention, there is provided an exposure apparatus for transferring a circuit pattern formed on a first object to a second object, wherein the first mark detects a position of the mark formed on the first object. A position detection system; a second mark position detection system for detecting a position of a mark formed on the second object; and the first object and the first mark based on detection results of the first and second mark position detection systems. A second exposure apparatus, wherein at least one of the first and second mark position detection systems includes the first measurement device of the present invention. is there.
According to this, since at least one specific mark position detection system of the first and second mark position detection systems has the first measuring device of the present invention, the specific mark position detection system In addition, it is possible to accurately measure at least one of a detection deviation (TIS) caused by the detection system and a detection deviation (WIS) caused by the formation state of the measurement target pattern, and the object to be detected (first object and second object). When detecting the position of the mark formed on at least one of the objects, it is possible to detect the mark position with high accuracy in consideration of the detection deviation measured with high accuracy. Then, the positions of the first object and the second object are controlled by the control system based on the detection results of the first and second mark position detection systems at the time of exposure. As a result, the overlay accuracy of the first object and the second object is improved, and the pattern of the first object can be accurately superimposed on the second object.
According to an eleventh aspect of the present invention, there is provided a detection system that sets a detection area at a predetermined point on the object and optically detects a pattern of the detection area via a detection optical system; Is irradiated with an imaging light beam, the reflected light from the object surface of the imaging light beam is photoelectrically detected, and a photoelectric conversion signal corresponding to the position of the object surface with respect to the optical axis direction of the detection optical system in the predetermined region is output. A first focus mechanism for driving the object in at least the optical axis direction; and relatively rotating the object and the detection optical system at least about 180 degrees around the axis in the optical axis direction. In the first state where the positional relationship between the object and the detection optical system is in a predetermined state, the focal position detection device is used to irradiate an irradiation region in the vicinity of the measurement target pattern on the object. Irradiating the imaging light beam; Based on the photoelectric conversion signal of the reflected light from the object surface of the imaging light beam, the position of the object surface in the optical axis direction is adjusted via the first drive mechanism, and in the state after the adjustment, A first detection control system for optically detecting the measurement target pattern using a detection system and detecting first in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern;
In the second state in which the object is rotated by 180 ° relative to the detection optical system from the first state via the second driving mechanism, the object is connected to the irradiation region using the focal position detection device. Adjusting the position of the object surface with respect to the optical axis direction via the first drive mechanism based on the photoelectric conversion signal of the reflected light from the object surface of the imaged light beam, and adjusting the position A second detection control system for detecting second in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern using the detection system in a later state; and the first and second in-plane positions; And a calculation device that calculates at least one of detection deviation caused by the detection system and detection deviation caused by the formation state of the measurement target pattern using information.
According to this, the first detection control system irradiates the irradiation region near the measurement target pattern on the object with the focal position detection device in the first state, and The position of the object surface in the optical axis direction is adjusted via the first drive mechanism based on the photoelectric conversion signal of the reflected light from the object surface, and the measurement target pattern is optically detected using the detection system in the state after the adjustment. The first in-plane position information in the plane orthogonal to the optical axis of the measurement target pattern is detected. For this reason, since the first in-plane position information can be obtained without defocusing, the first in-plane position information can be obtained with high accuracy.
In the second detection control system, the focus position detection device is used in the second state in which the object is rotated by 180 ° relative to the detection optical system from the first state via the second drive mechanism. Irradiating the irradiation region with an imaging light beam, adjusting the position of the object surface with respect to the optical axis direction via the first drive mechanism based on the photoelectric conversion signal of the reflected light from the object surface of the imaging light beam; In the state after the adjustment, second in-plane position information in a plane perpendicular to the optical axis of the measurement target pattern is detected using a detection system. In this case, since the same region is irradiated with the imaging light beam in the first state and the second state, the object is rotated 180 ° relative to the detection optical system from the first state. When adjusting the focus state, the focus state before rotation is accurately reproduced. Then, the position information in the second plane in the plane orthogonal to the optical axis of the measurement target pattern can be obtained in a state where this focus state is accurately reproduced and in the absence of defocus. Location information can be obtained.
Then, the calculation device calculates at least one of the detection deviation caused by the detection system and the detection deviation caused by the formation state of the measurement target pattern using the first and second in-plane position information obtained in this way. To do. Therefore, according to the present invention, it is possible to accurately measure at least one of the detection deviation caused by the detection system and the detection deviation caused by the formation state of the measurement target pattern without being affected by the inversion of the object with respect to the detection optical system. Can do.
From a twelfth aspect, the present invention is an exposure apparatus that exposes a photosensitive object with an energy beam to form a predetermined pattern on the object, and detects the position of a mark formed on the object. A mark position detection system; and a control device that controls a position of a previous object based on a detection result of the mark position detection system, wherein the mark position detection system includes the measurement device according to claim 15. It is the 3rd exposure apparatus characterized.
According to this, since the mark position detection system has the second measuring apparatus of the present invention, detection deviation (TIS) caused by the detection system and detection deviation (WIS) caused by the formation state of the measurement target pattern. Can be measured with high accuracy, and when detecting the position of the mark formed on the object, it is possible to detect the mark position with high accuracy in consideration of the detection deviation measured with high accuracy. Then, at the time of exposure, the position of the object is controlled by the control device based on the detection result of the mark position detection system. That is, exposure is performed while controlling the position of the object with high accuracy. Therefore, the pattern can be formed on the object with high accuracy.
According to a thirteenth aspect of the present invention, there is provided an exposure apparatus for transferring a circuit pattern formed on a first object to a second object, wherein the first mark detects a position of the mark formed on the first object. A position detection system; a second mark position detection system for detecting a position of a mark formed on the second object; and the first object and the first mark based on detection results of the first and second mark position detection systems. And a control system that controls the position of two objects, wherein at least one of the first and second mark position detection systems includes the second measuring device of the present invention. is there.
According to this, since the specific mark position detection system of at least one of the first and second mark position detection systems has the second measuring device of the present invention, the specific mark position detection system In addition, it is possible to accurately measure at least one of a detection deviation (TIS) caused by the detection system and a detection deviation (WIS) caused by the formation state of the measurement target pattern, and the object to be detected (first object and second object). When detecting the position of the mark formed on at least one of the objects, it is possible to detect the mark position with high accuracy in consideration of the detection deviation measured with high accuracy. Then, the positions of the first object and the second object are controlled by the control system based on the detection results of the first and second mark position detection systems at the time of exposure. As a result, the overlay accuracy of the first object and the second object is improved, and the pattern of the first object can be accurately superimposed on the second object.
Further, in the lithography process, by performing exposure using any one of the first to fourth exposure apparatuses of the present invention, a pattern can be formed on the object with high accuracy, thereby achieving higher integration. Microdevices can be manufactured with high yield. Similarly, in the lithography process, by using the first and second exposure methods of the present invention, a pattern can be formed on an object with high accuracy, thereby producing a highly integrated microdevice with high yield. can do. Therefore, from another viewpoint, the present invention is a device manufacturing method using any one of the first to fourth exposure apparatuses of the present invention or any of the first and second exposure methods of the present invention. It can also be said.

FIG. 1 schematically shows an exposure apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing the wafer holder of FIG. 1 partially broken together with the Z / tilt stage.
FIG. 3 is a diagram showing an internal configuration of the alignment sensor of FIG.
4A is a diagram showing a field stop plate, and FIG. 4B is a diagram showing a light shielding plate. 4C to 4G are diagrams showing other forms of the field stop plate.
5A and 5B are diagrams for explaining the arrangement of the reflectors constituting the first and second detection systems.
FIG. 6A is a diagram showing an imaging state on the line sensor when the wafer surface is at a position lower than the best focal plane, and FIG. 6B is an imaging state on the line sensor when the wafer surface is at the best focal plane. FIG. 6C is a diagram showing an imaging state on the line sensor when the wafer surface is at a position higher than the best focal plane.
FIG. 7 is a diagram showing the arrangement of alignment marks on the wafer.
FIG. 8A is a diagram illustrating a state in which the alignment mark AM1 is measured in a state of 0 °, and FIG. 8B is a diagram illustrating a state in which the alignment mark AM1 is measured in a state of 180 °.
FIG. 9A is a diagram illustrating a state in which the alignment mark AM2 is being measured at 0 °, and FIG. 9B is a diagram illustrating a state in which the alignment mark AM2 is being measured at 180 °.
FIG. 10A is a cross-sectional view showing a wafer and an alignment mark, and FIG. 10B is a graph showing measurement results according to the focus states of coma aberration and edge inclination.
FIG. 11A is a graph showing the amount of misalignment in the absence of focus offset, and FIG. 11B is a graph showing TIS and WIS calculation results obtained from the measurement results of FIG. 11A.
FIG. 12A is a graph showing the amount of positional deviation when there is a focus offset between the 0 ° state and the 180 ° state, and FIG. 12B shows the TIS and WIS calculation results obtained from the measurement results of FIG. 12A. It is a graph to represent.
FIG. 13 is a flowchart for explaining an embodiment of a device manufacturing method according to the present invention.
FIG. 14 is a flowchart showing details of step 204 in FIG.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of an exposure apparatus 100 according to an embodiment of the present invention. The exposure apparatus 100 is a step-and-scan projection exposure apparatus. The exposure apparatus 100 includes an illumination system 10, a reticle stage RST that holds a reticle R as a first object, a projection optical system PL, a wafer stage WST on which a wafer W as a second object is mounted, a reticle stage RST, and a wafer stage. A stage control device 19 that controls the WST, a main control device 20 that performs overall control of the entire device, and the like are provided.
The illumination system 10 includes a light source, an illuminance uniformizing optical system including an optical integrator, a relay lens, as disclosed in, for example, Japanese Patent Laid-Open No. 6-349701 and US Pat. No. 5,534,970 corresponding thereto. , A variable ND filter, a variable field stop (also called a reticle blind or a masking blade), a dichroic mirror, etc. (all not shown). Here, as the optical integrator, a fly-eye lens, an internal reflection type integrator (such as a rod integrator), or a diffractive optical element is used. To the extent permitted by national legislation in the designated or selected country designated in this international application, the disclosure in the above US patent is incorporated herein by reference.
The illumination system 10 divides a slit-like illumination area portion on a reticle R defined by the above-described reticle blind and extending in the X-axis direction (left and right direction in FIG. 1) into exposure illumination light (hereinafter “exposure light”). Illuminated with an almost uniform illuminance by EL. Here, as the exposure light EL, far ultraviolet light such as KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm) or F ₂ Vacuum ultraviolet light such as laser light (wavelength 157 nm) is used. As the exposure light EL, it is also possible to use an ultraviolet bright line (g-line, i-line, etc.) from an ultra-high pressure mercury lamp.
On reticle stage RST, reticle R having a circuit pattern PA formed on its pattern surface (lower surface in FIG. 1) is fixed, for example, by vacuum suction or the like. Reticle stage RST is in the XY plane perpendicular to the optical axis of illumination system 10 (coincided with optical axis AX of projection optical system PL, which will be described later) by reticle stage drive unit 12 including actuators such as a linear motor and a voice coil motor. And can be driven at a scanning speed designated in a predetermined scanning direction (here, the Y-axis direction which is a direction perpendicular to the paper surface in FIG. 1).
The position of the reticle stage RST in the stage moving surface is always detected by a reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 16 via the moving mirror 15 with a resolution of, for example, about 0.5 to 1 nm. . Position information of reticle stage RST from reticle interferometer 16 is supplied to stage controller 19 and main controller 20 via this. The stage control device 19 drives and controls the reticle stage RST via the reticle stage drive unit 12 based on the position information of the reticle stage RST in response to an instruction from the main control device 20.
The projection optical system PL is disposed below the reticle stage RST in FIG. 1, and the direction of the optical axis AX is the Z-axis direction. As the projection optical system PL, for example, a birefringent optical system having a predetermined reduction magnification (for example, 1/5 or 1/4) is used. For this reason, when the illumination area of the reticle R is illuminated by the exposure light EL from the illumination system 10, the exposure light EL that has passed through the reticle R causes the circuit of the reticle R in the illumination area to pass through the projection optical system PL. A reduced image (partially inverted image) of the pattern PA is formed on the wafer W whose surface is coated with a resist (photosensitive agent).
Wafer stage WST is disposed on a base (not shown) below projection optical system PL in FIG. 1, and is driven in the XY directions by a linear motor (not shown) constituting wafer stage drive unit 24. And a Z / tilt stage 30 which is mounted on the XY stage 31 and is finely driven in a Z-axis direction and an inclination direction with respect to the XY plane by a Z / tilt driving mechanism (not shown). A wafer holder 25 is provided on the Z / tilt stage 30, and the wafer W is sucked and held by the wafer holder 25.
The wafer holder 25 has a substantially disk shape, and as shown in FIG. 2 showing the wafer holder 25 partially broken together with the Z / tilt stage 30, a large number of wafer holders 25 having the same height are formed on the upper surface thereof. Pins 64 are provided. A large number of suction holes (not shown) are provided on the upper surface of the wafer holder 25 at positions where they do not mechanically interfere with a large number of pins 64, and the wafer W is vacuumed by a vacuum suction force of a vacuum pump (not shown) through these suction holes. Is held on the wafer holder 25 by suction.
Further, as shown in FIG. 2, the Z / tilt stage 30 has a round hole 72 into which the lower half of the wafer holder 25 can be fitted. The wafer holder 25 is fixed to the Z / tilt stage 30 by a vacuum suction force by a vacuum suction mechanism (not shown) with the lower half of the wafer holder 25 fitted in the round hole 72.
A vertical movement / rotation mechanism 74 is embedded in the bottom of the Z / tilt stage 30 at a position corresponding to the center of the bottom surface inside the round hole 72. This vertical movement / rotation mechanism 74 includes a motor (not shown) and the like, and is a mechanism capable of moving the drive shaft 75 whose one end is fixed to the bottom surface of the wafer holder up and down and rotating about 180 °. The vertical movement / rotation mechanism 74 constitutes a part of the wafer stage driving unit 24 of FIG. 1 and is controlled by the stage control device 19 of FIG.
Further, on the bottom surface inside the round hole 72, three vertical movement pins (center-up) 78 that are driven by a driving mechanism constituting the wafer stage driving unit 24 are provided. These vertical movement pins 78 are respectively formed at predetermined positions on the wafer holder 25 facing the vertical movement pins 78 in a state where the wafer holder 25 is fixed to the Z / tilt stage 30 by suction. The wafer holder 25 can be projected and retracted through a circular hole (not shown). Therefore, at the time of wafer exchange, the wafer W can be supported at three points by the three vertical movement pins 78 or can be moved up and down.
A reference mark plate 40 is fixed in the vicinity of the wafer W on the Z / tilt stage 30. The surface of the reference mark plate 40 is set to the same height as the surface of the wafer W, and a plurality of measurement marks to be described later, a so-called baseline measurement reference mark, a reticle alignment reference mark, etc. The mark is formed.
Returning to FIG. 1, the XY stage 31 scans not only to move in the scanning direction (Y-axis direction) but also to position a plurality of shot areas on the wafer W in an exposure area conjugate with the illumination area. It is configured to be movable also in a non-scanning direction (X-axis direction) orthogonal to the direction, and an operation for scanning (scanning) exposure of each shot area on the wafer W, and a scanning start position for exposure of the next shot ( Step-and-scan operation that repeats the movement to the acceleration start position) is performed.
The position of wafer stage WST in the XY plane (including rotation about the Z axis (θz rotation)) is transferred by wafer laser interferometer system 18 via moving mirror 17 provided on the upper surface of Z / tilt stage 30. For example, it is always detected with a resolution of about 0.5 to 1 nm. Here, actually, as shown in FIG. 2, the Y movable mirror 17Y having a reflecting surface orthogonal to the scanning direction (Y-axis direction) and the non-scanning direction (X-axis direction) are placed on the Z / tilt stage 30. Corresponding to this, a wafer laser interferometer system 18 correspondingly irradiates a Y interferometer beam perpendicularly to the Y movable mirror 17Y, and an X movable mirror 17X. An X interferometer that irradiates the interferometer beam perpendicularly to each other is provided. In FIG. 1, these are typically shown as a movable mirror 17 and a wafer laser interferometer system 18. That is, in this embodiment, a stationary coordinate system (orthogonal coordinate system) that defines the movement position of wafer stage WST is defined by the measurement axes of the Y interferometer and X interferometer of wafer laser interferometer system 18. Hereinafter, this stationary coordinate system is also referred to as a “stage coordinate system”. Note that at least one of the Y interferometer and the X interferometer of the wafer laser interferometer system 18 is a multi-axis interferometer having a plurality of measurement axes, and this interferometer allows the wafer stage WST (more precisely, Z · tilt). The θz rotation (yawing) of the stage 30) is also measured.
Position information (or velocity information) of wafer stage WST on the stage coordinate system is supplied to stage controller 19 and main controller 20 via this. In accordance with an instruction from main controller 20, stage controller 19 controls wafer stage WST via wafer stage drive unit 24 based on the position information (or speed information) of wafer stage WST.
Further, as shown in FIG. 1, in the exposure apparatus 100 of the present embodiment, the reticle mark on the reticle R and the mark on the reference mark plate 40 are simultaneously observed above the reticle R via the projection optical system PL. There are provided a pair of reticle alignment microscopes (hereinafter referred to as “RA microscopes” for convenience) RA1 and RA2 comprising a TTR (Through The Reticle) alignment optical system using light of an exposure wavelength for the purpose. The detection signals of these RA microscopes RA1 and RA2 are supplied to the main controller 20 via the alignment signal processing system 21. In this case, the deflection mirrors 50A and 50B composed of prisms for guiding the detection light from the reticle R to the RA microscopes RA1 and RA2, respectively, are movably arranged, and when an exposure sequence is started, a command from the main controller 20 is issued. Therefore, the deflecting mirrors 50A and 50B are retracted by the mirror driving device (not shown). The configuration equivalent to the RA microscopes RA1 and RA2 is disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 7-176468 and US Pat. No. 5,646,413 corresponding thereto. To the extent permitted by national legislation in the designated or selected country designated in this international application, the disclosure in the above publication and the corresponding US patent is incorporated herein by reference.
The exposure apparatus 100 further includes an off-axis alignment sensor 14 as a mark detection system. The alignment sensor 14 irradiates the mark on the reference mark plate 40 or the alignment mark on the wafer W with illumination light having a predetermined wavelength width, and conjugates the mark image with the reference mark plate 40 and the wafer W. An image of an index mark on an index plate arranged in a flat surface is formed on a light receiving surface of an image sensor (CCD or the like) by an objective lens or the like. Then, the imaging signal obtained as a result is output to the alignment signal processing system 21 and subjected to predetermined processing in the alignment signal processing system 21 to calculate position information of the detection target mark with respect to the center of the index mark, The position information is output to the main controller 20.
As shown in FIG. 3, the alignment sensor 14 includes a housing 130, a light source 103 provided outside the housing 130, a light guide 104 for guiding alignment light AL emitted from the light source 103 into the housing 130, Reflected by the condenser lens 105, the shutter 106B, the field stop plate 106A, the lens system 107, the first beam splitter 108, and the first beam splitter 108, which are sequentially arranged in the emission direction of light from the light guide 104 in the housing 130. Objective lens 109 arranged in the traveling direction of the light (−X side), lens system 111 arranged sequentially on the + X side of the first beam splitter 108, second beam splitter 112, and + Z side of the second beam splitter 112 In-sensor mark detection system 124 arranged on the + X side of the second beam splitter 112 The light shielding plate 113 has a first detecting system 123 disposed behind the light shielding plate 113 (+ X side) ₁ And the second detection system 123. ₂ Etc.
Here, a halogen lamp is used as the light source 103. As described above, the halogen lamp is used as the light source 103 because the wavelength range of the emitted light of the halogen lamp is 500 to 800 nm, and the wavelength range in which the photoresist coated on the upper surface of the wafer W is not exposed. This is because the influence of the wavelength characteristic of the reflectance on the surface of the wafer W can be reduced widely.
As shown in FIG. 4A, the field stop plate 106A has a measurement aperture OP having a substantially square shape formed at the center, and each side formed in the vicinity of each of the four sides of the measurement aperture OP. Four slit openings SO with the vertical direction as the longitudinal direction _X1 , SO _X2 , SO _Y1 , SO _Y2 And has. Accordingly, the shape of the image of the illumination light irradiated onto the wafer W is the measurement opening OP and the slit opening SO. _X1 ~ SO _Y2 And the same arrangement (see FIG. 8A). The shutter 106B provided in front of the optical path of the field stop plate 106A has a function of limiting the optical path of the alignment light AL, and the alignment light AL of the alignment light AL depends on the position of the alignment mark to be measured, which will be described later, on the wafer. Slit opening SO _X1 ~ SO _Y2 Incidence is selectively limited. The form of the slit opening is not limited to that shown in FIG. 4A, but can take various forms as shown in FIGS. 4C to 4G. In this embodiment, the field stop plate 106A of FIG. 4A is used. It will be described as being.
Returning to FIG. 3, the in-sensor mark detection system 124 arranged on the optical path of the light reflected by the second beam splitter 112 includes an index plate 120, a lens system 121, and an image sensor 122. .
The index plate 120 is arranged in a conjugate manner with the exposure surface of the wafer W with respect to the synthesis system of the objective lens 109 and the lens system 111 in the congruent state, and is arranged in a conjugate manner with the light receiving surface of the image sensor 122 with respect to the lens system 121. ing. The indicator plate 120 has an indicator mark formed of a chromium layer or the like on the surface of a transparent plate, and the portions other than the central portion are in a transparent state. This index mark is a position reference in a direction conjugate with the X-axis direction or the Y-axis direction on the wafer W.
The image sensor 122 is composed of, for example, a two-dimensional CCD, and captures and photoelectrically converts a reflected image of the alignment mark formed on the light receiving surface and a projected image of the index mark. In addition, an image signal obtained by photoelectric conversion is output to the alignment signal processing system 21.
On the other hand, as shown in FIG. 4B, the light shielding plate 113 arranged on the optical path of the light that has passed through the second beam splitter 112 is provided with a rectangular region 113a for light shielding at the center of the transparent plate. Thus, light incident on the portion (that is, light emitted from the measurement opening OP and reflected by the wafer surface) is not transmitted to the rear of the optical path. On the other hand, the light transmitted through the light shielding plate 113 is transmitted through the first and second detection systems 123. ₁ , 123 ₂ Is incident on.
The first detection system 123 ₁ Are the reflectors 114A and 114B, reflectors 115A and 115B disposed behind the optical path of light reflected by the reflectors 114A and 114B (+ Z side), and the optical path behind the reflected light at the reflectors 115A and 115B, respectively. The lens system 116A, the pupil division mirror 117A, the lens system 118A, and the line sensor 119A are sequentially arranged.
The second detection system 123 ₂ Is the reflectors 114C and 114D, reflectors 115C and 115D disposed behind the optical path of light reflected by the reflectors 114C and 114D (+ Z side), and the optical path behind the reflected light at the reflectors 115C and 115D, respectively. The lens system 116B, the pupil division mirror 117B, the lens system 118B, and the line sensor 119B are sequentially arranged.
In this case, the arrangement of the reflectors 114A to 114D is as shown in FIGS. 5A and 5B. That is, as shown in FIG. 5B, the reflecting plates 114A to 114D are arranged so as not to overlap each other when viewed from the + Z direction, and when viewed from the −X direction, the slit aperture SO of the field stop plate 106A. _X1 ~ SO _Y2 Illumination light (IL _X1 ~ IL _Y2 ).
Returning to FIG. 3, the pupil splitting mirrors 117A and 117B are composed of prisms formed in a mountain shape with an obtuse angle close to 180 degrees, and the two surfaces are finished as reflecting surfaces. In the present embodiment, the intersecting line (the ridgeline of the mountain) of the two surfaces as the reflecting surface intersects with the optical axis of the incident light, and the optical axis is tilted so as to swing approximately 90 degrees laterally. . The line sensors 119A and 119B are composed of a one-dimensional CCD or the like.
A prism mirror 110 is provided near the −X side of the objective lens 109 outside the housing 130 of the alignment sensor 14 for bending the optical path by 90 ° and guiding illumination light to the surface of the wafer W.
The operation of the alignment sensor 14 configured as described above will be described. The alignment light AL from the light source 103 is guided to a predetermined position in the housing 130 through the light guide 104. The alignment light AL emitted from the exit end of the light guide 104 enters the field stop plate 106A through the condenser lens 105, and the shape of the illumination light image irradiated on the wafer W is defined.
The illumination light that has passed through the field stop plate 106A enters the first beam splitter 108 via the lens system 107, and the illumination light reflected by the first beam splitter 108 passes through the objective lens 109, and then the housing 130. It is emitted from. When the illumination light is emitted from the housing 130, it is reflected by the prism mirror 110 and illuminates the vicinity of the alignment mark formed on the wafer W. In this case, the wafer W is arranged so that the region where the alignment mark is formed is substantially conjugate (image forming relationship) with the field stop plate 106A with respect to the combined system of the lens system 107 and the objective lens 109. At this time, since the illumination light IL is shaped by the field stop plate 106A, when the shutter 106B does not block the illumination light, the illumination light ML having a substantially square shape on the wafer W and four Slit illumination light IL _X1 , IL _X2 , IL _Y1 , IL _Y2 Are irradiated (see FIG. 8A and the like).
The reflected light reflected from the surface of the wafer W when the wafer W is irradiated with illumination light travels in the reverse direction of the optical path that has traveled previously, and is incident again on the first beam splitter 108 via the prism mirror 110 and the objective lens 109. . The light transmitted through the first beam splitter 108 enters the second beam splitter 112 via the lens system 111.
The light reflected by the second beam splitter 112 is received by the light receiving surface of the image sensor 122 via the index plate 120 and the lens system 121. Thereby, a reflected image of the alignment mark and a projected image of the index mark are formed on the light receiving surface of the image sensor 122. Then, light corresponding to these images is photoelectrically converted by the imaging device, and an imaging signal obtained by this photoelectric conversion is output to the alignment signal processing system 21. Then, in the alignment signal processing system 21, the positional information in the X-axis direction and the Y-axis direction regarding the wafer W is obtained as the X coordinate or Y coordinate of the alignment mark on the stage coordinate system described above based on the imaging signal.
On the other hand, the light transmitted through the second beam splitter 112 enters the light shielding plate 113. The light shielding plate 113 shields the reflected light of the illumination light ML from the wafer W.
Then, the four illumination lights IL from the wafer W that have passed through the light shielding plate 113 _X1 ~ IL _Y2 Two of the reflected lights of the first detection system 123 are arranged on the optical path. ₁ Are reflected by the reflectors 114A and 114B, and the remaining two lights are arranged on the optical path of the second detection system 123. ₂ Are reflected by the reflectors 114C and 114D. In this case, the reflecting plate 114A has illumination light IL. _Y1 Reflected light enters the reflector 114B and the illumination light IL is incident on the reflector 114B. _X1 Reflected light enters the reflector 114C and the illumination light IL is incident on the reflector 114C. _Y2 Reflected light enters the reflector 114D and the illumination light IL is incident on the reflector 114D. _X2 Reflected light is incident (see FIG. 5A).
Illumination light IL reflected by the reflectors 114A and 114B _Y1 , IL _X1 Are reflected again by the reflectors 115A and 115B and enter the pupil division mirror 117A via the lens system 116A. Here, in pupil division mirror 117A, two incident light (illumination light IL) _Y1 , IL _X1 ) Are each divided into two light beams, and a total of four divided light beams are imaged on the line sensor 119A. Thereby, the illumination light IL is placed on the line sensor 119A. _Y1 (Two images divided by pupil division mirror 117A) and illumination light IL _X1 Thus, a total of four images (two images divided by the pupil division mirror 117A) are formed. 6A to 6C show the illumination light IL. _X1 A state in which these two images are formed on the line sensor is representatively shown.
Here, when the surface of the wafer W coincides with the best focal plane of the alignment sensor 14, the illumination light IL imaged on the line sensor 119A. _X1 Is the distance d as shown in FIG. 6B. ₀ It shall be At this time, when the surface of the wafer W is at a position lower than the best focal plane of the alignment sensor 14, the focal point is at a position ahead of the optical path from the line sensor 119A as shown in FIG. 6A. The distance between the two images (the distance between the centers of the images) is the distance d in FIG. 6B. ₀ Shorter distance d _L Is measured by the line sensor 119A. On the other hand, when the surface of the wafer W is at a position higher than the best focal plane of the alignment sensor 14, as shown in FIG. 6C, the focal point is at the position behind the line sensor 119A. As the center distance), the distance d in FIG. ₀ Longer distance d _U Is measured by the line sensor 119A.
Thus, since the measurement result in the line sensor 119A differs depending on the position of the wafer W, the distance d between the two images when the wafer W is at the reference best focal plane. ₀ Is stored in a memory in the alignment signal processing system 21, and the position of the surface of the wafer W can be measured based on the value and the measured value.
Accordingly, the illumination light IL re-imaged on the line sensor 119A in a state where the mark of the reference mark plate 40 provided on the Z / tilt stage 30 and the imaging surface of the projection optical system PL coincide. _X1 The position of the reflected light image is stored in the alignment signal processing system 21 as a reference position. Note that the position of the image re-imaged on the line sensor 119A in the state where the alignment mark and the imaging surface of the projection optical system PL coincide using the alignment mark on the wafer instead of the reference mark plate 40 is the reference position. May be stored in the alignment signal processing system 21 in advance.
The other illumination light IL _Y1 The position of the surface of the wafer W using can be measured in the same manner as described above.
Thereafter, the line sensor 119 </ b> A captures an image formed on the light receiving surface and performs photoelectric conversion, and the photoelectrically converted electric signal is output toward the alignment signal processing system 21.
On the other hand, the illumination light IL reflected by the reflectors 114C and 114D _X2 , IL _Y2 Are reflected again by the reflectors 115C and 115D, and enter the pupil division mirror 117B through the lens system 116B. The light beams divided into two by the pupil division mirror 117B are incident on the line sensor 119B through the lens system 118B. As a result, the illumination light IL is placed on the line sensor 119B. _X2 Images (two images divided by pupil division mirror 117B) and illumination light IL _Y2 A total of four images (two images divided by the pupil division mirror 117B) are formed. Illumination light IL _X2 Image and illumination light IL _Y2 Are formed at different positions on the line sensor 119B. The line sensor 119B captures an image formed on the light receiving surface and performs photoelectric conversion. The photoelectrically converted electrical signal is output toward the alignment signal processing system 21.
In the alignment signal processing system 21, the illumination light IL _X1 , IL _Y1 (Or IL _X2 , IL _Y2 ), The position of the image formed on the line sensor 119A (or 119B) by the reflected light on the line sensor 119A (or 119B) is focused on the stored reference position (line sensor 119A (or 119B)). Illumination light at the time _X1 , IL _Y1 (Or IL _X2 , IL _Y2 ) (Position of image)) and the position shift in the Z-axis direction (position shift direction and position shift amount) of the alignment mark to be measured from the direction of occurrence of the lateral shift are detected.
Based on the amount of misalignment detected in this way, the stage controller 19 drives the Z / tilt stage 30 via the wafer stage drive unit 24 under the control of the main controller 20, thereby performing alignment. It is possible to align the surface of the wafer W with the best focal plane.
The exposure apparatus 100 further supplies an imaging light beam for forming a plurality of slit images toward the best imaging plane of the projection optical system PL from an oblique direction (not shown) that is oblique to the optical axis AX direction. An oblique incidence type multi-point focus detection system comprising a system and a light receiving optical system (not shown) that receives each reflected light beam of the imaging light beam on the surface of the wafer W through a slit is provided as a projection optical system PL. It is being fixed to the support part (illustration omitted) to support. As this multipoint focus detection system, for example, one having the same configuration as that disclosed in JP-A-6-283403 and US Pat. No. 5,448,332 corresponding thereto is used. 19 drives the Z / tilt stage 30 in the Z-axis direction and the tilt direction based on the wafer position information from the multipoint focus detection system. To the extent permitted by national legislation in the designated or selected countries designated in this international application, the disclosures in the above publications and US patents are incorporated herein by reference.
The main control device 20 includes a microcomputer or a workstation, and controls each part of the device in an integrated manner.
Next, a series of operations when the exposure processing of the second layer (second layer) and subsequent layers is performed on the wafer W by the exposure apparatus 100 of the present embodiment configured as described above will be described. .
First, reticle R is loaded onto reticle stage RST by a reticle loader (not shown). After loading of reticle R, main controller 20 performs reticle alignment and baseline measurement of alignment sensor 14.
Specifically, main controller 20 gives an instruction to stage controller 19 based on the measurement results of reticle interferometer 16 and wafer interferometer system 18, and uses wafer alignment microscopes RA1 and RA2 on wafer stage WST. A predetermined pair of first reference marks, for example, of four pairs of reticle alignment reference marks (hereinafter referred to as “first reference marks”) formed on the reference mark plate 40, and the reticle R corresponding thereto. The reticle stage RST and wafer stage WST are moved to a position where the image of the reticle mark can be simultaneously observed.
Next, main controller 20 uses reticle alignment microscopes RA1 and RA2 to measure the amount of positional deviation of a pair of reticle mark images corresponding to the predetermined pair of first reference marks.
Next, the main controller 20 gives an instruction to the stage controller 19 and moves the reference mark plate 40 and the reticle R in synchronization with the Y-axis direction at the projection magnification ratio, so that the other three pairs of reference marks are sequentially provided. The positional deviation amount of the reticle mark image with respect to is measured.
Then, main controller 20 determines the offset, rotational angle, distortion, and scanning direction of the positional deviation amount of the projected image of reticle R with respect to reference mark plate 40 and, consequently, wafer stage WST, from the positional deviation amounts of these four pairs of reticle marks. An angular deviation or the like is calculated, and the calculation result is stored in a temporary storage area in the RAM. This reticle alignment operation is disclosed in detail in the above-mentioned JP-A-7-176468 and US Pat. No. 5,646,413 corresponding thereto.
After the above reticle alignment, main controller 20 moves wafer stage WST so that fiducial mark plate 40 is arranged directly below alignment sensor 14, and is different from the first fiducial mark on fiducial mark plate 40. The amount of positional deviation of the second reference mark with respect to the detection center of the alignment sensor 14 is detected. Based on the detection result of the positional deviation amount, the measurement value of the wafer interferometer system 18 at this time, and the design baseline. A so-called baseline of the alignment sensor 14 is calculated.
When such a series of preparatory work is completed, before performing the exposure operation on the first wafer of one lot (lot first wafer), the detection deviation (TIS described later) of the alignment sensor 14 and the lot are described as follows. The leading wafer alignment operation is performed. In the present embodiment, two alignment marks (here, alignment marks AM1, Y1 for measurement in the Y-axis direction formed in the vicinity of the outer edge of the wafer W shown in FIG. 7) are used to calculate the detection deviation of the alignment sensor 14. A description will be given below of measuring the alignment mark AM2) for axial measurement. In addition, as an alignment mark, it is good also as employ | adopting the method of measuring several marks for each direction measurement, and taking the average value. In the following description, for convenience of description, the state of wafer W loaded on wafer stage WST is referred to as “0 ° state”.
a. First, the main controller 20 instructs the stage controller 19 to move the XY stage 31, and in response to this instruction, the stage controller 19 passes over the wafer W via the wafer stage drive unit 24. The XY stage 31 is driven so that the alignment mark AM <b> 1 (see FIG. 7) to be measured is positioned within the detection region (the irradiation region of the illumination light ML) of the alignment sensor 14. Further, main controller 20 drives shutter 106B to open aperture SO of field stop plate 106A. _X2 , SO _Y2 Is set to the shielding state.
In such a state, main controller 20 outputs a control signal to light source 103 to emit alignment light AL. When this alignment light AL is emitted, it is introduced into the alignment sensor 14 via the light guide 104, passes through the condenser lens 105, is shaped by the field stop plate 106A, and is illuminated by the illumination light IL. _X1 And illumination light IL _Y1 Is ejected. And illumination light IL _X1 , IL _Y1 Passes through the lens system 107, is reflected by the beam splitter 108, passes through the objective lens 109, is reflected by the prism mirror 110, and is irradiated onto the wafer W. The state at this time is shown in FIG. 8A.
Illumination light IL _X1 And illumination light IL _Y1 The reflected light from the light returns to the inside of the housing 130 via the prism mirror 110, and sequentially passes through the objective lens 109, the beam splitter 108, and the lens system 111, and the illumination light IL _X1 The reflected light is reflected in order by the reflectors 114B and 115B and enters the lens system 116A, and the illumination light IL. _Y1 The reflected light is reflected in turn by the reflectors 115A and 115B and enters the lens system 116A. The longitudinal direction of the image when entering the lens system 116A is parallel to each other. Then, the light is received by the line sensor 119A while being split into two light beams by the pupil splitting mirror 117A. On the light receiving surface of the line sensor 119A, these images are laterally shifted according to the position of the alignment mark AM1 in the Z-axis direction (the distance between the two light beams divided by the pupil division mirror is shifted from the reference position). Imaged. The electrical signal photoelectrically converted by the line sensor 119A is input to the alignment signal processing system 21 and subjected to signal processing.
Here, as shown in FIG. 8A, the illumination light IL irradiated to the portion other than the street line SL. _X1 The detection result of the reflected light by is not suitable for highly accurate position detection of the alignment mark AM1. This is because an error may occur in the focus measurement value due to the influence of the pattern or mark on the wafer W, more specifically, the influence of the unevenness due to the presence thereof.
In this case, illumination light IL is output by a signal output from wafer interferometer system 18, that is, based on the position of wafer stage WST. _X1 Therefore, the alignment signal processing system 21 can illuminate the illumination light IL in directions other than position measurement in order to eliminate unnecessary processing. _X1 It is set not to process the detection result by the reflected light.
Illumination light IL for illuminating a portion other than the street line SL _X1 The illumination light IL whose intensity is irradiated on the street line SL by diffraction by a circuit or the like formed in the shot area SA. _Y1 This is considered to be weaker than the intensity of the reflected light. Therefore, the alignment signal processing system 21 has the illumination light IL. _X1 Signal intensity of reflected light detection result and illumination light IL _Y1 It is also possible to compare the signal intensity of the detection result of the reflected light by and process only the detection result with the stronger intensity.
Further, the three slit openings may be shielded by a shutter so that only one of the four slit openings is used according to the position of wafer stage WST.
As described above, the alignment signal processing system 21 illuminates a portion other than the street line SL shown in FIG. 8A according to the position of the alignment mark AM1. _X1 The processing is not performed on the reflected light due to, and the deviation (defocusing) of the surface of the wafer W from the focal plane of the alignment sensor 14 is determined from the amount of lateral deviation of the detection signal with respect to the reference position stored in advance in the alignment signal processing system 21. ) Is detected. The main controller 20 drives the Z / tilt stage 30 via the wafer stage drive unit 24 so that the defocus amount on the upper surface of the wafer W becomes zero (so that the upper surface of the wafer W coincides with the best focal plane). In this manner, the alignment of the surface of the wafer W with the best focal plane of the alignment sensor 14 is performed.
b. As described above, when the wafer is aligned with the best focal plane, the main controller 20 images the alignment mark AM1. In this case, since the alignment light AL is continuously emitted from the light source 103, the reflected light (reflected light of the illumination light ML) reflected by the second beam splitter 112 is imaged through the index plate 120 and the lens system 121. Light is received by the element 122. The imaging result by the imaging element 122 is sent to the alignment signal processing system 21, and the Y coordinate of the alignment mark AM1 is calculated. The amount of deviation from the design value of the Y coordinate of the alignment mark AM1 (in the state of 0 °) here is dy. ₀ It shall be (f).
On the other hand, the same processing as that for the alignment mark AM1 is performed on the alignment mark AM2. That is, main controller 20 drives XY stage 31 so as to move alignment mark AM2 to a position corresponding to the detection region of alignment sensor 14, and in that state (the state of FIG. 9A), on street line SL. Illuminated illumination light IL _X1 The reflected light is detected by the line sensor 119A, and the wafer W surface is aligned with the best focal plane based on the detection result. Then, the alignment mark AM2 is imaged in a state where the alignment with the best focal plane is performed.
In this way, the X coordinate of the alignment mark AM2 is calculated. The amount of deviation from the design value of the X coordinate of the alignment mark AM2 (in the state of 0 °) here is dx in the following. ₀ It shall be expressed as (f).
c. Next, main controller 20 instructs stage controller 19 to rotate wafer W 180 ° within the XY plane. In response to this instruction, the stage control device 19 issues an instruction to the wafer stage drive unit 24 to drive the wafer holder 25 upward through the vertical movement / rotation mechanism 74 shown in FIG. 2 and 180 in the XY plane. The wafer holder 25 is driven to move downward in this state. Hereinafter, this state of the wafer W is referred to as a “180 ° state”.
d. The main controller 20 instructs the stage controller 19 to move the wafer W so that the alignment mark AM1 is positioned within the detection area of the alignment sensor 14 in the 180 ° state. The stage control device 19 drives the XY stage 31 via the wafer stage drive unit 24 in response to this instruction. By such an operation, the wafer W is substantially rotated (inverted) by 180 ° with respect to the optical axis of the alignment sensor 14 around the alignment mark AM1 of the wafer W.
Next, main controller 20 drives shutter 106B in alignment sensor 14 to provide slit opening SO. _X1 , SO _Y1 Shield. That is, from the field stop plate 106A on the surface of the wafer W, as shown in FIG. _X2 , IL _Y2 Is emitted and a part of the illumination light is off the street line SL. _Y1 Is not used for focus detection.
Next, main controller 20 outputs a control signal to light source 103 to emit alignment light AL, and slit aperture SO of field stop plate 106A. _X2 , SO _Y2 Illumination light IL that has passed through _X2 , IL _Y2 Illuminates the wafer W, is reflected by the surface of the wafer W, and passes through the first beam splitter 108 and the second beam splitter 112. One of these illumination lights IL _X2 Is reflected by the reflectors 114C and 115C, enters the lens system 116B, and the other illumination light IL _Y2 Is reflected by the reflectors 114C and 115D and enters the lens system 116B. The longitudinal directions of the images when entering the lens system 116B are parallel to each other. Then, the light is divided into two light beams by the pupil division mirror 117B and received by the line sensor 119B. On the light receiving surface of the line sensor, these images are formed in a state where the interval is shifted from the reference state according to the position of the alignment mark AM1 in the Z-axis direction. The electric signal photoelectrically converted by the line sensor 119B is input to the alignment signal processing system 21 and subjected to signal processing. Also in this case, the illumination light IL applied to the portion other than the street line SL shown in FIG. _X2 Are excluded from signal processing.
Then, the defocus of the alignment sensor 14 is detected from the lateral shift amount of the detection signal with respect to the reference position stored in advance in the alignment signal processing system 21. The main controller 20 moves the Z / tilt stage 30 through the wafer stage drive unit 24 so that the defocus amount of the wafer W becomes zero (so that the upper surface of the wafer W coincides with the best focal plane of the alignment sensor 14). Drive. In this way, the wafer W surface is aligned with the best focal plane.
e. Even in the 180 ° state, as in the 0 ° state, the main controller 20 images the alignment mark AM1 with the imaging element 122, and the alignment signal processing system 21 uses the imaging result with the imaging element 122. The Y coordinate of the alignment mark AM1 is calculated. In the following, the amount of deviation from the design value of the Y coordinate of the alignment mark AM1 calculated here is expressed as dy. ₁₈₀ It shall be expressed as (f).
Next, main controller 20 measures the position of alignment mark AM2 in this 180 ° state. In this case, as shown in FIG. 9B, the illumination light IL is placed on the wafer W as in FIG. 8B. _X2 , IL _Y2 Will be illuminated.
Main controller 20 drives XY stage 31 to move alignment mark AM2 to a position corresponding to the detection area of alignment sensor 14. Next, the illumination light IL _X1 The reflected light is detected by the line sensor 119A, and the wafer W is aligned with the best focal plane based on the detection result. Then, the alignment mark AM2 is imaged in a state where the alignment is performed, and thereby the X coordinate of the alignment mark AM2 is calculated. In the following, the amount of deviation from the design value of the X coordinate of the alignment mark AM2 calculated here is dx. ₁₈₀ It shall be expressed as (f).
f. When the above measurement is completed, main controller 20 causes b. And e. (WIS: Wafer Induced Shift) (X component is WISx (f) and Y component is WISy (f)). In addition, a misalignment component (TIS: Tool Induced Shift) (X component is defined as TISx (f) and Y component as TISy (f)) is calculated according to the following equations (1) to (4).
TISx (f) = {dx ₀ (F) + dx ₁₈₀ (F)} / 2 (1)
WISx (f) = {dx ₀ (F) -dx ₁₈₀ (F)} / 2 (2)
TISy (f) = {dy ₀ (F) + dy ₁₈₀ (F)} / 2 (3)
WIsy (f) = {dy ₀ (F) -dy ₁₈₀ (F)} / 2 (4)
Here, the effect | action of the said measurement is demonstrated concretely.
FIG. 10B shows the coma aberration and the edge inclination independently for an alignment mark having a cross-sectional shape as shown in FIG. 10A (here, X mark, line width in the X direction is 6 μm, and the width of the inclined portion is 0.2 μm). The measurement result of the amount of misalignment is shown (the numerical aperture of the detection optical system in the alignment sensor 14 is 0.3, using a halogen lamp light source).
Here, in the actual measurement of the amount of misalignment, as shown in FIG. 11A, a measurement including both coma aberration and edge inclination in each state is measured.
Then, when TISx (f) and WISx (f) are obtained using the above formulas (1) and (2) based on the result shown in FIG. 11A, the result shown in FIG. 11B is obtained. As can be seen by comparing FIG. 11B and FIG. 10B, TISx (f) and WISx (f) calculated from the actual measurement values substantially coincide with the coma aberration and the edge inclination.
On the other hand, when a focus offset occurs between the 0 ° state and the 180 ° state, that is, when the focus state at the time of measuring the alignment mark fluctuates, the focus state in the 0 ° state is set to f, The amount of deviation from the design value of the X mark in the state is dx ₀ (F) The focus state in the 180 ° state is f ′, and the deviation amount from the design value of the X mark in this state is dx. ₁₈₀ Assuming (f ′), the misalignment component TIS caused by the alignment sensor 14 and the misalignment component WIS caused by the deformation of the wafer W can be expressed by the following equations (5) and (6).
TIS = {d ₀ (F) + d ₁₈₀ (F ')} / 2
= {T (f) + T (f ')} / 2+ {W (f) -W (f')} / 2 (5)
WIS = {d ₀ (F) -d ₁₈₀ (F ')} / 2
= {W (f) + W (f ')} / 2+ {T (f) -T (f')} / 2 (6)
In this way, when there is a focus offset, the measurement deviation amount from the actual mark position measured in the 0 ° state and the 180 ° state is as shown in FIG. 12A, and the result of FIG. TIS and WIS calculated from (5) and (6) are as shown in FIG. 12B. As can be seen from a comparison between FIG. 12B and FIG. 11B, it can be seen that accurate TIS and WIS cannot be calculated if a focus offset occurs in the 0 ° state and the 180 ° state.
As described above, in order to calculate accurate TIS and WIS, it is important to match the focus state in the 0 ° state and the 180 ° state, and the focus state can be accurately determined as in this embodiment. When measurement of the alignment mark in the matched state is realized, it is possible to calculate accurate values of TIS and WIS.
g. Next, in main controller 20, alignment marks formed on the wafer in association with a plurality of measurement target shot areas (sample shot areas) (at least three marks each including X and Y including alignment marks AM1 and AM2). The measurement results are corrected by subtracting the TIS and WIS from the respective measurement results. Based on the corrected values, for example, Japanese Patent Application Laid-Open No. 61-44429 and the corresponding US Pat. No. 4 , 780, 617, etc., fine alignment is performed by an enhanced global alignment (EGA) method that calculates the array coordinates of shot areas on the wafer W by statistical calculation using the least square method disclosed in detail. To the extent permitted by national legislation in the designated or selected country designated in this international application, the disclosure in the above publication and the corresponding US patent is incorporated herein by reference.
Next, main controller 20 exposes each shot area on wafer W by a step-and-scan method. This exposure operation is performed as follows.
That is, the stage controller 19 controls the wafer stage drive unit 24 while monitoring the measurement values of the X-axis and Y-axis interferometers according to the command given from the main controller 20 based on the alignment result described above. Wafer stage WST is moved to a scan start position (acceleration start position) for exposure of the first shot of wafer W. At this time, as the alignment result, the position information of the alignment mark AMn obtained by correcting the TIS and WIS of the alignment sensor 14 as described above is used, and the scanning start position is calculated based on the shot arrangement coordinates obtained accordingly. Therefore, if the wafer stage WST is moved in accordance with the command from the main controller 20, the position control of the wafer stage WST is performed so as to correct the TIS and WIS of the alignment sensor 14 as a result. It becomes.
Next, stage controller 19 starts relative scanning in the Y-axis direction between reticle R and wafer W, that is, reticle stage RST and wafer stage WST, in accordance with an instruction from main controller 20. When both stages RST and WST reach their respective target scanning speeds and reach a constant speed synchronization state, the pattern area of the reticle R starts to be illuminated by the ultraviolet pulse light from the illumination system 10, and scanning exposure is started. The relative scanning is performed by the stage controller 19 controlling the reticle driving unit and the wafer stage driving unit 24 (not shown) while monitoring the measurement values of the wafer laser interferometer system 18 and the reticle interferometer 16 described above. Is called.
In the stage controller 19, particularly during the scanning exposure described above, the movement speed Vr of the reticle stage RST in the Y-axis direction and the movement speed Vw of the wafer stage WST in the Y-axis direction are determined by the projection magnification (1/4) of the projection optical system PL. The synchronous control is performed so that the speed ratio is maintained according to (multiple or 1/5 times).
Then, different areas of the pattern area of the reticle R are sequentially illuminated with ultraviolet pulse light, and the illumination of the entire pattern area is completed, whereby the scanning exposure of the first shot on the wafer W is completed. Thereby, the pattern of the reticle R is reduced and transferred to the first shot via the projection optical system PL.
As described above, when the scanning exposure of the first shot is completed, based on an instruction from the main controller 20, the stage controller 19 causes the wafer stage WST to move in the X and Y axis directions via the wafer stage drive unit 24. It is moved stepwise and moved to the scanning start position for exposure of the second shot.
Then, in accordance with an instruction from the main controller 20, the operation of each part is controlled by the stage controller 19 and a laser controller (not shown) in the same manner as described above, and the same as described above for the second shot on the wafer W. Scanning exposure is performed.
In this way, the scanning exposure of the shot on the wafer W and the stepping operation for the next shot exposure are repeated, and the pattern of the reticle R is sequentially transferred to all the exposure target shots on the wafer W.
Thereafter, using the TIS and WIS measured using the first wafer of the one lot, the alignment mark measurement results for the remaining wafers of one lot are corrected, and the alignment operation and exposure are performed in the same manner as described above. The operation is repeated.
As apparent from the above description, in the present embodiment, the light source 103, the light guide 104, the condenser lens 105, the field stop plate 106A, the lens system 107, the first beam splitter 108, the objective lens 109, the prism mirror 110, and the lens. The system 111, the second beam splitter 112, and the in-sensor mark detection system 124 constitute a detection system. In this case, the detection optical system is configured by the objective lens 109, the lens system 111, and the lens system 121 constituting the in-sensor mark detection system 124. The light source 103, the light guide 104, the condenser lens 105, the field stop plate 106A, the shutter 106B, the lens system 107, the first beam splitter 108, the objective lens 109, and the prism mirror 110 constitute an irradiation system. Lens 109, first beam splitter 108, lens system 111, second beam splitter 112, light shielding plate 113, first position detection system 123 ₁ , Second position detection system 123 ₂ Thus, a light receiving system is configured. In this case, a focus position detection device is configured including the irradiation system and the light receiving system, and the pattern detection device is configured by the alignment sensor 14 including the focus position detection system, the detection system, and the like.
Further, the first drive mechanism is constituted by the vertical movement pins 78 and the wafer stage drive unit 24, and the second drive mechanism is constituted by the vertical movement / rotation mechanism 74 and the wafer stage drive unit 24. The main control device 20 constitutes a calculation device, and the main control device 20 and the stage control device 19 constitute a first detection control system and a second detection control system, and these, the first drive mechanism, A measurement device is configured including the two drive mechanism and the alignment sensor 14.
As described above in detail, according to the pattern detection device (alignment sensor 14) and the pattern detection method of the present embodiment, the focal position detection device constituting the alignment sensor 14 is placed in the detection region of the alignment mark on the wafer W. At least one set that is rotationally symmetric with respect to each other and extends in a direction away from the detection region, and here, two sets of irradiation regions each have illumination light IL. _X1 , IL _X2 , IL _Y1 , IL _Y2 It has the above-mentioned irradiation system which can irradiate. For this reason, illumination light is irradiated to a certain irradiation region (first irradiation region) on the wafer W from the irradiation system, and the photoelectric conversion signal of the reflected light from the surface of the wafer W by the line sensor 119A (or 119B). The optical axis direction position of the surface of the wafer W is detected based on the detection result, the optical axis direction position of the wafer W is adjusted based on the detection result, and then the detection optical system of the alignment sensor 14 with the wafer W as the center of the detection region. Rotate (reverse) 180 ° with respect to. In the state after the wafer W is inverted, the first irradiation region coincides with the irradiation region (second irradiation region) that forms a pair with the first irradiation region before the inversion. Accordingly, after the wafer W is inverted, the second irradiation area on the wafer W before the inversion (that is, the first irradiation area on the object after the inversion) is irradiated with illumination light (imaging light flux), and the illumination light By detecting the position in the optical axis direction of the surface of the wafer W based on the photoelectric conversion signal of the reflected light from the surface of the wafer W, and adjusting the position in the optical axis direction of the wafer W based on this detection result, the same focus as before the inversion The state is accurately reproduced. Accordingly, it is possible to accurately reproduce the focus state before the inversion after the inversion of the wafer W on which the alignment mark to be detected is formed.
Further, according to the measurement apparatus and the measurement method of the present embodiment, the main controller 20 is configured such that the alignment mark on the wafer W is in a state where the positional relationship between the wafer W and the detection optical system of the alignment sensor 14 is 0 °. The illumination region is irradiated with illumination light, and the reflected light from the surface of the wafer W is received and the photoelectric conversion signal output from the line sensor 119A (or 119B) is received via the stage control device 19 and the like. Then, the position of the surface of the wafer W in the optical axis direction is adjusted, and in the state after the adjustment, the alignment mark 14 is optically detected, and the position information of the alignment mark in the XY plane is detected. . For this reason, since position information in the XY plane can be obtained without defocusing, position information in the XY plane can be obtained with high accuracy.
The main controller 20 also rotates the wafer W from 0 ° through 180 ° relative to the detection optical system of the alignment sensor 14 through 180 ° and 180 °. An optical axis on the surface of the wafer W via the stage controller 19 or the like based on a photoelectric conversion signal output from a line sensor that irradiates illumination light different from the state and receives reflected light from the surface of the wafer W. While adjusting the position regarding the direction, the position information in the XY plane of the alignment mark is detected in the state after the adjustment. In this case, since the illumination light can be illuminated on the same region in the 0 ° state and the 180 ° state, the wafer W is rotated 180 ° relative to the alignment sensor 14 from the 0 ° state. When the focus state is adjusted, the focus state before the rotation is accurately reproduced. Then, since the position information in the XY plane of the alignment mark can be obtained in a state where the focus state is accurately reproduced and there is no defocus, the position information in the XY plane can be obtained with high accuracy.
Then, main controller 20 uses the two pieces of position information thus obtained to detect at least a detection deviation (TIS) caused by alignment sensor 14 and a detection deviation (WIS) caused by the alignment mark formation state. One is calculated. Therefore, it is possible to accurately measure at least one of TIS and WIS without being affected by the reversal of the wafer W with respect to the alignment sensor 14.
In addition, by calculating the position of the wafer W based on one of the two pieces of positional information obtained with high accuracy and the calculated detection deviation (at least one of TIS and WIS), the influence of the detection deviation can be reduced. The position information of the wafer W can be accurately obtained without receiving it.
Further, according to the exposure apparatus and exposure method of the present invention, at least one of the detection deviation (TIS) caused by the alignment sensor 14 and the detection deviation (WIS) caused by the formation state of the alignment mark is accurately measured by the measurement apparatus. Therefore, when detecting the position of the alignment mark formed on the wafer W, it is possible to detect the mark position with high accuracy in consideration of the detection deviation measured with high accuracy. Then, the main controller 20 controls the position of the wafer W based on the detection result of the alignment sensor 14 at the time of exposure. That is, exposure is performed while controlling the position of the wafer W with high accuracy. Therefore, a pattern can be formed on the wafer W with high accuracy.
In the above embodiment, illumination light that irradiates the street line SL on the surface of the wafer W is used as illumination light used for focus position detection. As a method, the main controller 20 drives the shutter 106B in the alignment sensor 14. However, the present invention is not limited to this, and the same illumination light is used as the illumination light to be used. Measurement may be performed by moving wafer stage WST so that the illumination light is illuminated in the same area where illumination light is illuminated in the state. Even if it does in this way, the effect similar to the said embodiment is acquired, and the drive of a shutter etc. become unnecessary.
In the above embodiment, in the focus position detection performed before the measurement of the alignment mark AM2, as shown in FIG. 9B, illumination light is illuminated on the same region on the wafer in the 0 ° state and the 180 ° state. Therefore, in the state of 0 °, the illumination light IL _X1 In the state of 180 °, the illumination light IL _X2 However, the present invention is not limited to this, and the illumination light IL is set in both the 0 ° state and the 180 ° state as in the alignment mark AM2 in FIG. 9B. _X1 Is located on the street line SL, in any case, the illumination light IL _X1 It is also possible to perform focus position detection using.
A state as shown in FIG. 9B (illumination light IL _X1 And IL _X2 Can be determined based on the mark and the design value of the street line SL. Or illumination light IL _X1 , IL _X2 By comparing the signal intensities of the reflected light, it can be determined that the signal is in the state as shown in FIG. 9B, the same illumination light (illumination light IL in the case of FIG. 9B) is used as the illumination light used for measurement at 0 ° and 180 °. _X1 ) Can be used to reduce the measurement error (because a common detection system is used).
In the above-described embodiment, the illumination light is switched using the shutter 106B. However, the illumination light sources emitted from the respective slit openings are separately provided to control the turning on and off of each light source. Thus, the illumination light to be used may be switched.
In the above-described embodiment, when the focal position of the surface of the wafer W is adjusted, the illumination light is illuminated with the alignment mark extending in the four directions of the ± X direction and the ± Y direction. However, the present invention is not limited to this, and the field stop plate as shown in FIGS. 4C to 4G is used to move in any of ± X direction, ± Y direction, or oblique direction (for example, 45 ° direction). It is good also as employ | adopting the structure that illumination light is illuminated in the state extended in the extended state or those combination directions. These various types of field stops may be configured on the turret, and any one of them may be switched and arranged on the detection optical path. In that case, an appropriate field stop may be switched and arranged in accordance with the arrangement of the mark, the pattern state, the process conditions, and the like.
In the above embodiment, the case where the mark detection system of the present invention is employed in an apparatus for measuring a mark on a wafer has been described. However, instead of or in combination with this, measurement of a mark on a reticle is performed. The mark detection system of the present invention may be employed in the alignment microscopes RA1 and RA2 that perform the above.
In the above embodiment, when the wafer W is rotated from the 0 ° state to the 180 ° state, the wafer holder 25 holding the wafer W is rotationally driven via the vertical movement / rotation mechanism 74. However, the means for rotating the wafer W is not limited to this, and the wafer W may be temporarily collected via a wafer loader (not shown), and the wafer W may be placed on the wafer holder 25 again after the rotation. Alternatively, a mechanism for rotating the alignment sensor 14 may be provided, and the alignment sensor 14 may be rotated in a horizontal plane through which the alignment sensor 14 is rotated.
In the above embodiment, when measuring a plurality of marks (AM1, AM2) at 0 ° and 180 °, respectively, all marks (AM1, AM2) are first measured at 0 °, and then the holder is rotated 180 °. However, the present invention is not limited to this, and the measurement of 0 ° and 180 ° is sequentially performed for each mark (that is, the mark AM1 is measured at 0 ° and 180 °). After the measurement, the mark AM2 may be measured at 0 ° and 180 °). However, in order to minimize the number of rotations of the holder and minimize the measurement time, it is desirable to employ a sequence like this embodiment.
In the above embodiment, the case where the present invention is applied to a scanning stepper has been described. However, the present invention is not limited to this, and the present invention can also be applied to a stationary exposure apparatus such as a step-and-repeat stepper. In such a case, when performing static exposure, the wafer can be accurately positioned at the exposure position (reticle pattern projection position), and the reticle pattern is accurately superimposed and transferred onto a desired partition area on the wafer. can do.
An illumination optical system composed of a plurality of lenses, a projection optical system, and an alignment sensor 14 are incorporated in the exposure apparatus main body to perform optical adjustment, and a reticle stage and wafer stage composed of a large number of mechanical parts are incorporated in the exposure apparatus main body. The exposure apparatus of the above-described embodiment can be manufactured by attaching and connecting wirings and pipes and further performing general adjustment (electrical adjustment, operation check, etc.). The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.
The present invention is not limited to an exposure apparatus for manufacturing a semiconductor, but is used for manufacturing a display including a liquid crystal display element. An exposure apparatus for transferring a device pattern onto a glass plate and a device used for manufacturing a thin film magnetic head. The present invention can also be applied to an exposure apparatus for transferring a pattern onto a ceramic wafer, an exposure apparatus used for manufacturing an imaging device (CCD or the like), a micromachine, a DNA chip, and the like. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates or silicon wafers, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern. Here, in an exposure apparatus using DUV (far ultraviolet) light, VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used. As a reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, Magnesium fluoride or quartz is used. Further, in a proximity type X-ray exposure apparatus or an electron beam exposure apparatus, a transmission mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate.
Furthermore, the measurement method and the measurement apparatus according to the present invention are not limited to the exposure apparatus, but can be applied to any apparatus provided with an imaging type mark detection system.
Furthermore, the mark detection system to which the present invention is applied is not limited to the image formation type mark detection system as described above, and is, for example, a double detection as disclosed in International Publication WO98 / 39689. Folded mark detection system, phase difference detection mark detection system as disclosed in WO99 / 27567, or scattered light from mark edges as disclosed in JP-A-10-141915 The present invention is also applicable to a mark detection system that detects the intensity of light.
By the way, when a detection error occurs during the detection of the alignment mark AM (for example, the detection of the mark detection system (alignment sensor) 14 due to the influence of an unexpected large vibration such as an earthquake or the like, or a malfunction of the stage drive system or the control system). In the case where the range deviates from the detection target area (mark AM area) on the wafer and the mark cannot be detected, the exposure apparatus temporarily stops (interrupts) the mark detection operation, and the wafer stage (XY) The stage 31, Z / tilt stage 30) is returned to the initial position (reset position, for example, the positions where X, Y, Z positions are all 0, 0, 0 in the wafer stage coordinate system). ").
Therefore, in the exposure apparatus of the above-described embodiment, the remeasurement sequence divided into the following cases may be executed in each process of 0 ° measurement and 180 ° measurement.
(I) When the wafer stage is reset during 0 ° measurement:
In this case, the XY stage 31 is automatically set back (moved) to the 0 ° measurement target mark position based on the mark position on the design value. In this case, the following sequence is adopted for the Z / tilt stage 30 depending on the situation. That is, suppose that AF measurement (position measurement of the wafer W in the Z-axis direction by the above-described focus position detection device constituting the alignment sensor 14) has already been completed and the defocus amount in 0 ° measurement has already been calculated before the wafer stage reset. If (ie, the optimum Z position is known), the return is automatically set (moved) to the calculated Z position. On the other hand, if the AF measurement is not completed before the wafer stage is reset, the Z / tilt stage 30 is automatically set to the reference Z position (for example, a Gaussian image plane position uniquely defined on the design value of the alignment optical system). After resetting (moving), the AF measurement operation is restarted from the reference Z position to obtain the optimum Z position, and then the Z / tilt stage 30 is aligned.
(Ii) When the wafer stage is reset during 180 ° measurement:
In this case, the XY stage 31 is automatically set back (moved) to the 180 ° measurement target mark position based on the mark position on the design value. In this case, the following sequence is adopted for the Z / tilt stage 30 depending on the situation. That is, if the AF measurement has already been completed before the wafer stage reset and the defocus amount in 180 ° measurement has been calculated (that is, the optimum Z position is known), the calculated Z position is set to the calculated Z position. Set to return automatically (move). On the other hand, if AF measurement is not completed before the wafer stage is reset, the Z / tilt stage 30 is set to the reference Z position or the Z position (0 ° Z position) at the time of 0 ° measurement already completed. (Move), the AF measurement operation is restarted from the reference Z position or 0 ° Z position to obtain the optimum Z position, and then the Z / tilt stage 30 is aligned.
The above-described measurement restart sequence is applied not only to 0 ° and 180 ° measurement but also to a scene of normal EGA measurement (sample shot measurement already described in the description of the embodiment).
That is, for example, when the above-described wafer stage reset is performed during measurement of the alignment mark AM3 associated with the sample shot area (measurement target shot area), the XY stage 31 is set with the mark AM3 based on the design value of the mark AM3. Move back to a detectable position. Also in this case, the following sequence is adopted for the Z / tilt stage 30 depending on the situation. That is, if the AF measurement has already been completed and the defocus amount has been calculated before the wafer stage is reset (that is, the optimum Z position is known), the automatic return setting to the calculated Z position is set. On the other hand, if AF measurement is not completed before the wafer stage is reset, the Z / tilt stage 30 has the reference Z position or a measurement target mark (for example, AM1) that has already been measured. Is automatically set back (moved) to the Z position at the time of measurement of the mark AM1 (AM position at the time of AM1 measurement), and the AF measurement operation is resumed from the reference Z position or the Z position at the time of AM1 measurement to obtain the optimum Z After obtaining the position, the Z / tilt stage 30 is aligned.
Note that the above-described wafer stage reset is performed when the measurement target mark is formed on the wafer with a large deviation from the design position (so that even if the XY stage 31 is positioned based on the mark design value, the mark detection system (alignment It may also be executed when a mark does not enter the detection area of the sensor 14). In such a case, there is a possibility that even if the XY stage 31 is moved back as described above, the measurement target mark cannot be observed within the detection region of the mark detection system (alignment sensor) 14. In such a case, the signal from the mark detection system is displayed on the observation monitor, and the XY stage 31 is manually moved from the position where the apparatus is automatically restored while the user of the apparatus looks at the monitor to detect the detection area of the mark detection system. It is sufficient to operate so that the mark is inside.
The wafer stage reset described above may also be executed when the mark itself is deformed due to the influence of various processes applied to the wafer and measurement is impossible. In such a case, the user observes the mark observation image at the automatically restored position (X, Y, Z position) on the observation monitor described above, and the user is determined to be an unmeasurable mark from the observation result. When the determination is made, the mark (mark detection control system) may be instructed to restart the measurement of the mark to be measured next without measuring the mark as an error mark.
<Device manufacturing method>
Next, an embodiment of a device manufacturing method using the above-described exposure apparatus 100 in a lithography process will be described.
FIG. 13 shows a flowchart of a manufacturing example of a device (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). As shown in FIG. 13, first, in step 201 (design step), device function / performance design (for example, circuit design of a semiconductor device) is performed, and pattern design for realizing the function is performed. Subsequently, in step 202 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.
Next, in step 204 (wafer processing step), using the mask and wafer prepared in steps 201 to 203, an actual circuit or the like is formed on the wafer by lithography or the like as will be described later. Next, in step 205 (device assembly step), device assembly is performed using the wafer processed in step 204. Step 205 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary.
Finally, in step 206 (inspection step), inspections such as an operation confirmation test and durability test of the device created in step 205 are performed. After these steps, the device is completed and shipped.
FIG. 14 shows a detailed flow example of step 204 in the semiconductor device. In FIG. 14, in step 211 (oxidation step), the surface of the wafer is oxidized. In step 212 (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode formation step), an electrode is formed on the wafer by vapor deposition. In step 214 (ion implantation step), ions are implanted into the wafer. Each of the above-described steps 211 to 214 constitutes a pre-processing process at each stage of the wafer processing, and is selected and executed according to a necessary process at each stage.
At each stage of the wafer process, when the above pre-process is completed, the post-process is executed as follows. In this post-processing process, first, in step 215 (resist formation step), a photosensitive agent is applied to the wafer. Subsequently, in step 216 (exposure step), the circuit pattern of the mask is transferred to the wafer by the exposure apparatus and exposure method described above. Next, in step 217 (development step), the exposed wafer is developed, and in step 218 (etching step), the exposed members other than the portion where the resist remains are removed by etching. In step 219 (resist removal step), the resist that has become unnecessary after the etching is removed.
By repeatedly performing these pre-processing steps and post-processing steps, multiple circuit patterns are formed on the wafer.
If the device manufacturing method of this embodiment described above is used, the exposure apparatus of the above embodiment is used in the exposure step (step 216), so that the overlay accuracy between the reticle pattern and each shot area on the wafer W is improved. The reticle pattern can be transferred onto the wafer with high accuracy. Therefore, the yield of the micro device that is the final product is improved, and the productivity can be improved.

  As described above, the pattern detection apparatus of the present invention is suitable for detecting a pattern formed on an object. Further, the method of using the pattern detection apparatus of the present invention is suitable for obtaining position information of a pattern formed on an object. The measurement method of the present invention is suitable for measuring at least one of a detection deviation caused by the detection system and a detection deviation caused by the formation state of the measurement target pattern. The position measurement method of the present invention is suitable for obtaining position information of an object. The exposure method and exposure apparatus of the present invention are suitable for forming a pattern on an object with high accuracy. The device manufacturing method of the present invention is suitable for mass production of microdevices.

Claims (19)

A pattern detection device for optically detecting a pattern formed on an object,
A detection system that sets a detection area at a predetermined point on the object and optically detects a pattern of the detection area via a detection optical system;
An irradiation system capable of irradiating an imaging light beam to at least one set of irradiation areas that are rotationally symmetric with respect to the detection area on the object and extend in a direction away from the detection area, respectively, Light reception that photoelectrically detects reflected light from the object surface of the image light beam and outputs a photoelectric conversion signal corresponding to the position of the object surface in the optical axis direction of the detection optical system in the irradiation region irradiated with the imaging light beam And a focus position detecting device having a system. The pattern detection apparatus according to claim 1,
The pattern detection apparatus according to claim 1, wherein the irradiation system is capable of irradiating two sets of irradiation regions that are rotationally symmetric with respect to the predetermined point in the two orthogonal directions. It is a usage method of the pattern detection apparatus of Claim 1, Comprising:
In the first state in which the positional relationship between the object on which the measurement target pattern is formed and the detection optical system is in a predetermined state, the focus position detection device is placed in a predetermined irradiation region near the measurement target pattern on the object. Irradiating the first imaging light beam from the irradiation system to constitute, and adjusting the position of the object surface in the optical axis direction of the detection optical system based on a photoelectric conversion signal output from the light receiving system;
An in-plane perpendicular to the optical axis of the measurement target pattern is detected optically using the detection system in a state where the position of the object surface in the optical axis direction of the detection optical system is adjusted. Obtaining the first in-plane position information of;
In a second state in which the object is rotated from the first state by 180 ° relative to the detection optical system, a second different from the first imaging light beam from the irradiation system to the irradiation region. Irradiating an imaging light beam and adjusting the position of the object surface with respect to the optical axis direction of the detection optical system based on a photoelectric conversion signal output from the light receiving system;
In a state in which the position of the object surface in the optical axis direction is adjusted, the detection target pattern is optically detected using the detection system, and the second in-plane position within the plane orthogonal to the optical axis of the measurement target pattern A method of using comprising: obtaining information. The method according to claim 3, wherein
A step of calculating at least one of a detection deviation caused by a detection system and a detection deviation caused by a formation state of the measurement target pattern using the first and second in-plane position information. how to use. A position measurement method for measuring the position of an object using the pattern detection device according to claim 1,
In the first state in which the positional relationship between the object on which the measurement target pattern is formed and the detection optical system is in a predetermined state, the focus position detection device is placed in a predetermined irradiation region near the measurement target pattern on the object. Irradiating the first imaging light beam from the irradiation system to constitute, and adjusting the position of the object surface in the optical axis direction of the detection optical system based on a photoelectric conversion signal output from the light receiving system;
An in-plane perpendicular to the optical axis of the measurement target pattern is detected optically using the detection system in a state where the position of the object surface in the optical axis direction of the detection optical system is adjusted. Obtaining the first in-plane position information of;
In a second state in which the object is rotated from the first state by 180 ° relative to the detection optical system, a second different from the first imaging light beam from the irradiation system to the irradiation region. Irradiating an imaging light beam and adjusting the position of the object surface with respect to the optical axis direction of the detection optical system based on a photoelectric conversion signal output from the light receiving system;
In a state in which the position of the object surface in the optical axis direction is adjusted, the detection target pattern is optically detected using the detection system, and the second in-plane position within the plane orthogonal to the optical axis of the measurement target pattern Obtaining information;
Calculating at least one of a detection deviation caused by a detection system and a detection deviation caused by the formation state of the measurement target pattern using the first and second in-plane position information;
Calculating a position of the object based on one of the first in-plane position information and the second in-plane position information and the calculated detection deviation. An exposure method for exposing a photosensitive object with an energy beam to form a predetermined pattern on the object,
Measuring the position of the object by the position measuring method according to claim 5;
Exposing the object with the energy beam while controlling the position of the object based on the measured position information. In a first state in which the positional relationship between the object on which the measurement target pattern is formed and the detection optical system is in a predetermined state, an imaging light beam is irradiated onto a predetermined irradiation region in the vicinity of the measurement target pattern on the object. A step of photoelectrically detecting the reflected light from the object surface of the imaging light beam through the detection optical system to obtain first position information of the object surface in the irradiation area in the optical axis direction of the detection optical system; ;
In a state where the position of the object surface in the optical axis direction is adjusted based on the first position information, the measurement target pattern is optically detected using a detection system including the detection optical system. A first detection step of obtaining first in-plane position information in a plane perpendicular to the optical axis;
In the second state in which the object is rotated from the first state by 180 ° relative to the detection optical system, the irradiation region is irradiated with an imaging light beam, and the imaging light beam is emitted from the object surface. Photoelectrically detecting reflected light to obtain second position information of the object surface with respect to the optical axis direction of the detection optical system in the irradiation region;
A surface perpendicular to the optical axis of the measurement target pattern, which optically detects the measurement target pattern using the detection system in a state where the position of the object surface in the optical axis direction is adjusted based on the second position information. A second detection step for obtaining position information on the second surface of the inside;
Calculating at least one of a detection deviation caused by the detection system and a detection deviation caused by the formation state of the measurement target pattern using the first and second in-plane position information. The measurement method according to claim 7,
In the first state, the imaged light beam is irradiated in the second state substantially in the same region as the predetermined irradiation region on the object irradiated with the imaged light beam. The measurement method further comprising a step of moving the object in a plane orthogonal to the optical axis in a period after the first detection step and before the second detection step. The measurement method according to claim 7,
A plurality of imaging light beams can be irradiated on the object;
In order that the imaging light beam is irradiated even in the second state to a region substantially the same as the predetermined irradiation region on the object irradiated with the imaging light beam in the first state. A measuring method, wherein the imaging light beam irradiated onto the object is switched and used in the first detection step and the second detection step. A position measurement method for measuring the position of an object,
In a first state in which the positional relationship between the object on which the measurement target pattern is formed and the detection optical system is in a predetermined state, an imaging light beam is irradiated onto a predetermined irradiation region in the vicinity of the measurement target pattern on the object. A step of photoelectrically detecting the reflected light from the object surface of the imaging light beam through the detection optical system to obtain first position information of the object surface in the irradiation area in the optical axis direction of the detection optical system; ;
In a state where the position of the object surface in the optical axis direction is adjusted based on the first position information, the measurement target pattern is optically detected using a detection system including the detection optical system. A first detection step of obtaining first in-plane position information in a plane perpendicular to the optical axis;
In the second state in which the object is rotated from the first state by 180 ° relative to the detection optical system, the irradiation region is irradiated with an imaging light beam, and the imaging light beam is emitted from the object surface. Photoelectrically detecting reflected light to obtain second position information of the object surface with respect to the optical axis direction of the detection optical system in the irradiation region;
A surface perpendicular to the optical axis of the measurement target pattern, which optically detects the measurement target pattern using the detection system in a state where the position of the object surface in the optical axis direction is adjusted based on the second position information. A second detection step for obtaining position information on the second surface of the inside;
Calculating at least one of a detection deviation caused by the detection system and a detection deviation caused by the formation state of the measurement target pattern using the first and second in-plane position information;
Calculating a position of the object based on one of the first in-plane position information and the second in-plane position information and the calculated detection deviation. An exposure method for exposing a photosensitive object with an energy beam to form a predetermined pattern on the object,
Measuring the position of the object by the position measuring method according to claim 10;
Exposing the object with the energy beam while controlling the position of the object based on the measured position information. A detection system that sets a detection region at a predetermined point on the object and optically detects a pattern of the detection region via a detection optical system;
An irradiation system capable of irradiating at least one set of irradiation regions, each of which is rotationally symmetric with respect to the detection region on the object and extending in a direction away from the detection region; A light receiving system for photoelectrically detecting reflected light from the object surface and outputting a photoelectric conversion signal corresponding to the position of the object surface with respect to the optical axis direction of the detection optical system in the irradiation region irradiated with the imaging light beam; A focal position detection device having;
A first drive mechanism for driving the object at least in the optical axis direction;
A second drive mechanism capable of rotationally driving the object and the detection optical system at least about 180 ° around the axis in the optical axis direction;
In the first state in which the positional relationship between the object and the detection optical system is in a predetermined state, the irradiation system in the vicinity of the measurement target pattern on the object has a first connection from the irradiation system constituting the focal position detection device. The direction of the optical axis of the object surface via the first drive mechanism based on a photoelectric conversion signal output from the light receiving system that irradiates an image light beam and receives reflected light from the object surface of the imaged light beam In the state after the adjustment, the measurement target pattern is optically detected using the detection system, and the first in-plane position in the plane perpendicular to the optical axis of the measurement target pattern is adjusted. A first detection control system for detecting information;
In the second state in which the object is rotated by 180 ° relative to the detection optical system from the first state via the second driving mechanism, the first connection is made from the irradiation system to the irradiation region. A second imaging light beam different from the image light beam is irradiated, and a reflected light from the object surface of the imaging light beam is received, and a photoelectric conversion signal output from the light receiving system is received via the first drive mechanism. Adjusting the position of the object surface with respect to the optical axis direction and, in the state after the adjustment, using the detection system, second in-plane position information in a plane perpendicular to the optical axis of the measurement target pattern is obtained. A second detection control system to detect;
And a calculation device that calculates at least one of a detection deviation caused by the detection system and a detection deviation caused by the formation state of the measurement target pattern using the first and second in-plane position information. An exposure apparatus that exposes a photosensitive object with an energy beam to form a predetermined pattern on the object,
A mark position detection system for detecting a position of a mark formed on the object;
A control device for controlling the position of the front object based on the detection result of the mark position detection system;
An exposure apparatus, wherein the mark position detection system includes the measurement apparatus according to claim 12. An exposure apparatus for transferring a circuit pattern formed on a first object to a second object,
A first mark position detection system for detecting a position of a mark formed on the first object;
A second mark position detection system for detecting a position of a mark formed on the second object;
A control system for controlling the positions of the first object and the second object based on detection results of the first and second mark position detection systems;
An exposure apparatus, wherein at least one of the first and second mark position detection systems includes the measurement apparatus according to claim 12. A detection system that sets a detection region at a predetermined point on the object and optically detects a pattern of the detection region via a detection optical system;
Irradiating a predetermined region on the object with an imaging light beam, photoelectrically detecting reflected light from the object surface of the imaging light beam, and depending on the position of the object surface in the predetermined region with respect to the optical axis direction of the detection optical system A focus position detection device for outputting a photoelectric conversion signal;
A first drive mechanism for driving the object at least in the optical axis direction;
A second drive mechanism capable of rotationally driving the object and the detection optical system at least about 180 ° around the axis in the optical axis direction;
In the first state in which the positional relationship between the object and the detection optical system is in a predetermined state, the imaging light flux is irradiated onto an irradiation area near the measurement target pattern on the object using the focal position detection device. And adjusting the position of the object surface in the optical axis direction via the first drive mechanism based on the photoelectric conversion signal of the reflected light from the object surface of the imaging light beam, and in the state after the adjustment A first detection control system for optically detecting the measurement target pattern using the detection system and detecting first in-plane position information in a plane orthogonal to the optical axis of the measurement target pattern;
In the second state in which the object is rotated by 180 ° relative to the detection optical system from the first state via the second driving mechanism, the object is connected to the irradiation region using the focal position detection device. Adjusting the position of the object surface with respect to the optical axis direction via the first drive mechanism based on the photoelectric conversion signal of the reflected light from the object surface of the imaged light beam, and adjusting the position A second detection control system for detecting second in-plane position information in a plane perpendicular to the optical axis of the measurement target pattern using the detection system in a later state;
And a calculation device that calculates at least one of a detection deviation caused by the detection system and a detection deviation caused by the formation state of the measurement target pattern using the first and second in-plane position information. An exposure apparatus that exposes a photosensitive object with an energy beam to form a predetermined pattern on the object,
A mark position detection system for detecting a position of a mark formed on the object;
A control device for controlling the position of the front object based on the detection result of the mark position detection system;
An exposure apparatus, wherein the mark position detection system includes the measurement apparatus according to claim 15. An exposure apparatus for transferring a circuit pattern formed on a first object to a second object,
A first mark position detection system for detecting a position of a mark formed on the first object;
A second mark position detection system for detecting a position of a mark formed on the second object;
A control system for controlling the positions of the first object and the second object based on detection results of the first and second mark position detection systems;
An exposure apparatus, wherein at least one of the first and second mark position detection systems includes the measurement apparatus according to claim 15. A device manufacturing method including a lithography process,
In the said lithography process, it exposes using the exposure apparatus as described in any one of Claim 13, 14, 16, 17, The device manufacturing method characterized by the above-mentioned. A device manufacturing method including a lithography process,
12. A device manufacturing method using the exposure method according to claim 6 or 11 in the lithography process.

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