JPH11194502A - Imaging apparatus, shape measuring apparatus, position detecting apparatus, and exposure apparatus and device manufacturing method using the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To realize a configuration capable of measuring a shape at high speed and with high accuracy without in principle requiring movement of a large member in the optical axis direction. A light source capable of generating light of a plurality of wavelengths, an imaging optical system for forming an optical image of a test object illuminated by light from the light source, and a photoelectric conversion device for converting the optical image And an imaging element 9 for converting the light.
including.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging apparatus, a shape measuring apparatus, a position detecting apparatus, and an exposure apparatus and a device manufacturing method using the same. The present invention provides, for example, a reticle in a projection exposure apparatus used in a lithography process in a process of manufacturing a semiconductor device such as an IC or an LSI, an imaging device such as a CCD, a display device such as a liquid crystal panel, or a device such as a magnetic head. This is suitable for performing relative positioning between the reticle and the wafer when projecting a pattern on the first object plane onto the second object plane on the wafer by the projection optical system.

[0002]

2. Description of the Related Art In recent years, the integration of semiconductor devices such as ICs and LSIs has been increasingly accelerated, and the fine processing technology for semiconductor wafers has been remarkably advanced.

As this fine processing technique, a reduction projection exposure apparatus (stepper) for forming a circuit pattern image of a mask (reticle) on a photosensitive substrate by a projection optical system (projection lens) and sequentially exposing the photosensitive substrate in a stepwise manner. It has been known. In this stepper, a circuit pattern on a reticle is reduced and projected onto a predetermined position on a silicon wafer surface via a projection optical system having a predetermined reduction magnification, and is transferred. The step of moving the stage on which is mounted by a predetermined amount and performing the transfer again is repeated, thereby exposing the entire surface of one wafer.

In general, a single wafer undergoes several tens of process steps until the completion of an IC element. In that process,
The role of a stepper is to align (align) a new circuit original pattern with a circuit pattern already formed on a wafer by printing in the previous step, and then project the pattern and print it in a superimposed manner.

[0005] At this time, if the overlapping state is not good, the performance of the IC element, for example, a decrease in the operation speed, a failure, and an increase in the defective rate are caused. As described above, as semiconductor devices become more highly integrated and circuit pattern line widths become narrower, it is necessary to further improve the alignment accuracy.

A mark on the wafer for alignment, ie, an alignment mark, usually has a slit-like shape. The alignment mark is enlarged by an optical system and photoelectrically converted by an image sensor to obtain grayscale image information. A TTL (Through The Lens) system, which is also used as a projection exposure optical system for printing a pattern on this optical system, and an Off Axis system, which is detected by a microscope separately from the projection exposure optical system It has been known. Usually, both of the advantages and disadvantages are taken into consideration, and the position of the alignment mark is detected from the obtained grayscale image. The wafer is controlled to a desired position based on the detected positional deviation amount of the wafer.

[0007] Here, the shape of the edge of the alignment mark is drooped or raised every time the process is performed. The more these problems become, the higher the hurdle of high accuracy is required, and high accuracy of alignment is required.

Therefore, there has been considered a direction in which the three-dimensional shape information of the alignment mark is detected and used for the alignment information.

One method for detecting the three-dimensional shape of an alignment mark is a confocal microscope method.
1 to 3 show a conventional method for detecting three-dimensional information with a confocal microscope.

FIG. 1 shows an example of a conventional confocal microscope. The light beam emitted from the light source 1A, which illuminates the sample 2 on the stage 2A, is polarized by a polarizing beam splitter (PB).
Only S-polarized light is reflected by S) 3, and this reflected light is converted into circularly-polarized light by the λ / 4 plate 4 and passes through a pinhole array 7A called a Nippow disk.

The Nippou disk 7A comprises a row of pinholes as shown in FIG.
Rotate 00 times. The sample 2 to be observed and the Nippow disk 7A are in an optically conjugate relationship with respect to the imaging optical system 6. First, the rotation of the Nippow disk 7A will be described.

A light beam transmitted through a certain pinhole, for example, 72 forms an image at a corresponding point on the sample 2 by the imaging optical system 6 and illuminates the image. Next, the reflected light travels in the same path in the opposite direction with the intensity distribution of the sample in the illumination area, and passes through the pinhole 72. The luminous flux passes through the λ / 4 plate 4, changes from circularly polarized light to P-polarized light, and passes through the PBS 3.

On the other hand, the image pickup device 9 and the Nippow disk 7 are in a conjugate relationship with respect to the imaging system optics 8. The light beam passing through the pinhole 72 is photoelectrically converted by the imaging system 9, and an image of the binhole portion is stored in the signal processing device 10.

Next, when the Nippou disk 7A rotates, the pinhole 72 scans, and thus the illumination area on the sample 2 surface is scanned. Thereby, in the imaging system 9, an image on one scanning line is obtained. On the other hand, as shown in FIG. 2, a pinhole 73 is provided on the Nippow disk 7A slightly apart from the pinhole 72, and the pinhole 73 similarly performs scanning. The distance between the pinholes is equal to or larger than the size determined by the resolution of the imaging optical system. For example, the distance between the pinholes is designed so that the image of the pinhole 72 does not cover the pinhole 73.

The image formed by the pinhole 73 is also
The image is obtained by the imaging system 9 in the same manner as in the case of (1), and an image on one scanning line is obtained in the signal processing device 10. The above operation is performed while the Nippow disk 7A is rotating, and the signal processing device 10 obtains the image of the sample 2 from the scan images of all pinholes.

FIG. 3 shows an example in which three-dimensional information is obtained. The optical system is partially omitted. Now, the sample 2 has been moved along the optical axis around the position in the conjugate relationship to the imaging optical system 6, where (1) is far from the conjugate position, (2) is the conjugate position, ( 3) shows a case before the conjugate position. As is clear from the high-speed focusing state (spot diameter) on the Nippow disk 7A, the light flux spreads on the pinhole except for (2),
Therefore, the position of the sample in the optical axis direction can be detected by associating the maximum value of the amount of light that reaches the image sensor through the pinhole with the moving distance of the sample in the optical axis direction. A dimensional shape can be detected.

[0017]

To improve the alignment, it is essential to detect the three-dimensional shape of the alignment mark. The above-described confocal microscope is an example of detecting a three-dimensional shape. However, as described above, if the conventional method is used as it is, the wafer to be observed is mechanically moved in the optical axis direction,
There is a problem that the three-dimensional shape detection time is limited. For example, when trying to detect a three-dimensional shape at TV rate, 200
It is necessary to move a large wafer of mmφ or more by several μm in the optical axis direction within 10 msec or less.

On the other hand, it is conceivable to move the Nippou disk in the optical axis direction. However, these methods have limitations because they have a movable part for moving a large member such as a Nippow disk in the direction of the optical axis with a large resistance, which may be a source of foreign matter or a source of disturbance such as vibration. there were.

In view of the above-mentioned conventional example, the present invention provides a shape measuring apparatus capable of measuring a shape at high speed and with high accuracy without the need of moving a large member in the optical axis direction in principle, and an alignment using the same. A light beam, a position detection device capable of executing position detection with high accuracy with a mark, an imaging device suitably used for this, a high-speed, high-precision device manufacturing method using the same, and an exposure device suitably used for this. The purpose is to provide.

[0020]

According to a first aspect of the present invention, there is provided a light source capable of generating light of a plurality of wavelengths, and an optical image of a test object illuminated by the light from the light source. An imaging optical system for converting the optical image and an imaging device for photoelectrically converting the optical image, wherein the imaging optical system includes a diffractive optical element.

The second invention is further characterized in that the diffraction optical element is a binary optical element.

According to a third aspect of the present invention, there is further provided a variable wavelength light source for illuminating the test object.

The fourth invention is further characterized in that the light source is a semiconductor laser.

According to a fifth aspect of the present invention, there is further provided an aperture means having an aperture group, which illuminates the object to be inspected with a light beam from the aperture group, and transmits the image of the object to the imaging optical system through the aperture group. A confocal optical system that forms an image on the image sensor.

A sixth invention is further characterized in that the opening means is a light valve in which each opening constituting the opening group can be independently controlled.

The seventh invention is further characterized in that the light valve is a micro mirror device.

The eighth invention is further characterized in that the light valve is a liquid crystal device.

According to a ninth aspect of the present invention, an image of a test object is formed through a diffractive optical element to separate the image of the test object at each image forming position by an image forming wavelength. ,
A shape measuring apparatus characterized in that a shape including at least a component in an imaging optical axis direction of a test object is measured from an image at each imaging position.

A tenth aspect of the present invention is further characterized in that the three-dimensional shape of the test object is measured from the image at each of the image forming positions.

In the eleventh aspect, the object is illuminated by changing the wavelength over time to obtain an image of the object at each imaging position by temporally separating the image at the imaging wavelength. It is characterized by the following.

The twelfth invention is further characterized in that the diffraction optical element is a binary optical element.

A thirteenth invention for achieving the above object is
By forming an alignment mark provided on the object through a diffractive optical element, an image of the alignment mark for each image forming position is separated by an image forming wavelength, and using the image for each image forming position. A position detecting device for obtaining position information of the object.

According to a fourteenth aspect of the present invention, the position information of the object is obtained by obtaining shape information of the alignment mark using an image at each of the image forming positions, and obtaining information of a deviation from a predetermined position of the alignment mark from the shape information. It is characterized by obtaining information.

According to a fifteenth aspect, there is provided an exposure apparatus using any one of the above-described image pickup devices as an alignment mark detecting means.

A sixteenth aspect of the present invention is a method for manufacturing a device, characterized in that any one of the above-described imaging devices is used for alignment mark detection, the wafer is positioned based on the detection, pattern transfer is performed, and a circuit is formed. is there.

According to a seventeenth aspect, there is provided an exposure apparatus using any one of the above-described shape measuring devices as an alignment mark detecting means.

According to an eighteenth aspect of the present invention, there is provided a method of manufacturing a device, comprising using one of the above-described shape measuring devices for alignment mark detection, positioning a wafer based on the detection, and performing pattern transfer to form a circuit. It is.

According to a nineteenth aspect, there is provided an exposure apparatus using any one of the above-described position detecting devices.

A twentieth aspect of the present invention is a method for manufacturing a device, characterized in that any one of the above-described position detecting devices is used, a wafer is positioned based on the position detected by the device, and a pattern is transferred to form a circuit. is there.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following embodiments, at least one objective lens of a microscope for observing an alignment mark or the like is constituted by a binary optical element (BO). BO is known to have a wavelength dispersion 10 times or more larger than that of ordinary glass. Normal glass has a wavelength dispersion of 20 to 90, but BO has a value of -3. That is, when the wavelength of BO is longer, the focal point is on the BO side, but in a normal glass material, the focal point is on the lens side as the wavelength is shorter. Therefore,
Instead of mechanically moving the sample to be observed, the imaging position can be moved in the optical axis direction by changing the center wavelength of the observation light.

If the objective lens using the BO is applied to a confocal microscope, detection of a three-dimensional shape can be equivalently realized. Furthermore, if a confocal microscope using this BO is applied to the alignment optical system of the exposure apparatus, the three-dimensional shape can be detected without mechanically moving the wafer, and alignment can be performed based on the three-dimensional shape. By
High-precision alignment that does not affect process distortion can be realized.

Hereinafter, a detailed description will be given with reference to the drawings. FIG. 4 is a schematic diagram of Embodiment 1 of the present invention. The same members as those described above are denoted by the same reference numerals. The light source 1 is a light source whose center wavelength is variable, and may be an incoherent light source such as a halogen lamp or a coherent light source such as a laser. The light beam from the light source 1 travels to a polarizing beam splitter (PBS) 3. Reference numeral 5 denotes a polarizing plate that selectively transmits only S-polarized light reflected by the polarizing beam splitter 3 from among the light beams from the light source 1.

The λ / 4 plate 4 has the property of rotating the plane of polarization by 90 ° when transmitted twice back and forth. S polarized light from PBS3 is PBS
After being reflected, the light is converted into circularly polarized light by the λ / 4 plate 4. Then, the λ / 4 plate 4 is irradiated onto the sample 2 and is reflected by the sample 2.
The reflected light is converted into P-polarized light and transmitted through PBS3.

6 is a refractive optical element (here, a lens system),
Reference numeral 7 denotes a diffractive optical element. The optical elements 6 and 7 are image forming optical systems that bring the sample 2 and the imaging element 9 into an optically conjugate relationship as a whole. The optical system shown here is shown only as a conceptual diagram, and a specific design configuration deviates from the essence.

FIG. 5 illustrates the diffractive optical element 7. The basic configuration of the diffractive optical element 7 is described by a Fresnel zone plate as shown in FIG. Light waves from concentric adjacent transit zones generate a phase difference of one wavelength (2π) and interfere with each other. For example, if the width and the pitch are set to a predetermined value, the first-order diffracted light waves from each orbicular zone are focused on one point. Therefore, if only the first-order diffracted light is considered, the imaging element has no aberration.

However, since the diffracted light other than the first-order diffracted light is simultaneously irradiated on the image surface as a ghost or a flare,
There is a practical problem. This defect is compensated for by a phase type diffraction element called a kinoform, which is shown in FIG.

This device can concentrate the diffraction efficiency only on a desired diffraction order (for example, first-order light), so that the disadvantage of the Fresnel zone plate can be eliminated.

On the other hand, this type has difficulty in production.
The solution to this problem is what is called a binary optical element (BO element) as shown in FIG. This is a multi-stage approximation of the shape of a phase type diffraction grating utilizing lithography technology.
The desired diffracted light (usually the first order) can be obtained with a step shape at an efficiency of 95%.

As described above, when the center wavelength of the light source shifts, the light condensing position of the BO element greatly changes. By utilizing this property, the image plane in the optical axis direction can be moved.

Returning to FIG. 4, the description will be continued. Center wavelength λ
The sample 2 irradiated with 0 has an optically conjugate relationship with the imaging device 9. Next, when the wavelength of the light source is scanned from λ0 to λ, the focal length of the BO element changes as described above. Since the position of the imaging element 9 does not change, the optical conjugate position on the object side moves. In other words, this corresponds to mechanically transferring the sample in the optical axis direction.
A cut plane image perpendicular to the optical axis of the sample is projected on the image sensor 9, a plurality of images are obtained while moving the cut plane in the optical axis direction, and the plurality of images are reproduced by the signal processing device 10. With this configuration, a three-dimensional shape of the sample can be obtained.

In a binary optical element, the relationship between wavelength and focal length can be expressed as f = (λ0 / λ) f0. Where λ
0 and f0 are the reference wavelength and the focal length at that time. Therefore, when the wavelength is changed by dλ, the change df of the focal point is df = −
(Λ0f0 / λ ^** 2) dλ. Here, when the wavelength change is small, λ0 = λ, and the above equation is df = − (f0 /
λ) dλ. For example, here, λ is 800 nm, f0
Is 5 mm and df is 10 μm, dλ = 1.6 nm.
That is, if a wavelength change of only about 2 nm is given, 10 μm
Focus transfer of about m can be realized.

On the other hand, a semiconductor laser is known as one of the easy-to-use variable wavelength light sources. This light source can control wavelength control by temperature, injection current, and the like. Particularly in the case of injection current, high-speed modulation is also possible.

As is known, a semiconductor laser has two kinds of wavelength changes, one of which is called mode hop.
These are discrete changes of about nm and continuous changes before a mode hop of about several nm. By utilizing this continuous change, a focus transfer in the optical axis direction of about 10 μm as shown in the above example can be realized.

FIGS. 6 and 8 are schematic diagrams of second and third embodiments to which the present invention is applied, respectively. These embodiments show examples in which the optical system of the first embodiment is combined with a confocal system. FIG. 6 shows a case where a reflection light valve is used, and FIG. 8 shows a case where a transmission light valve is used. It is. The same members as those described above are denoted by the same reference numerals, and description thereof will be omitted.

Hereinafter, a second embodiment will be described with reference to FIG. In this embodiment, the light valve 20 and the sample 2 are in an optically conjugate relationship. 8 is also an imaging optical system and a light valve 20
And the imaging cord 9 are in an optically conjugate relationship. Reference numeral 12 denotes a moving mechanism that can move the sample 2 in the optical axis (height) direction of the imaging system 6 and can move the sample 2 by a predetermined amount in accordance with a command from the processing device 20.

FIG. 7 is a schematic view showing the reflection type light valve 20 realized by a micro mirror device.
Are assembled. In this micromirror device, the size of one mirror is a rectangle having a side of several μm to several hundred μm. The number of mirrors ranges from several thousand to several million and is arranged in a matrix. The overall size of the micro mirror device 20 is a rectangle having a side of several millimeters to several tens of millimeters. In FIG. 7, this is schematically illustrated by eight micromirrors.

In FIG. 7, pixels, that is, small mirrors 201 to 2
08 independently deflects the angle between the mirror and the electrode 209 using the electromagnetic force by the attractive force or repulsive force around the support portion, and changes the angle of the reflected light to turn ON / OF the reflected light.
F control can be performed. For example, in FIG. 7, the micromirrors 201, 203, 206, and 208 are in the OFF state, while 202, 204, 205, and 207 are in the 0N state.

Returning to the description of FIG. The micromirror device 20 sets a predetermined pixel (micromirror) pattern to 0N in response to a command from the processing device 10. The light beam from the light source 1 is reflected by the beam splitter 11, reflected by the PBS 3 after passing through the polarizing plate 5, and enters the micromirror device 20 through the λ / 4 plate 4. The micromirror device 20 in which a predetermined pixel pattern is in the ON state reflects the sampled ON pixel pattern and illuminates the sample 2. The reflected light from the illuminated sample travels in the same path to the micromirror device 20 in the reverse direction, and is reflected by the pixel pattern portion which is also ON. The reflected light from this pixel pattern reverses the optical path to the PBS 3, is reflected by the PBS 3, forms an image on the image sensor 9, is photoelectrically converted by the image sensor 9, and is stored in the storage unit in the signal processing device 10. .

Next, the processing apparatus 10 has the minute mirror device 2
By controlling 0, another pixel pattern is generated, and by repeating this series of operations, a substantial scan of the sample surface is executed, and a desired image can be obtained. Thus, a series of operations for capturing an image is completed. In this series of operations, one image can be obtained in 1 msec or less by selectively scanning only a necessary portion of the sample and a high-speed response of the minute mirror device 20.

Next, a control signal for shifting the wavelength from the processing system 10 to the light source 1 is issued to obtain a three-dimensional (three-dimensional) shape. Then, the imaging plane moves in the optical axis direction. Then, an image at that height is captured in the same manner as described above. The light source 1 is sequentially operated to store a plurality of images in the height direction, and three-dimensional information can be obtained from information in the height direction of the image having the highest luminance of the corresponding pixel. And get the above tertiary information
It can be realized within 33msec of TV rate.

FIG. 8 shows an example in which the light valve 20 is replaced with a transmissive light valve in the second embodiment, and specifically, an example in which the light valve 20 is formed of liquid crystal. The form of the optical system is different from the first embodiment in that the transmission type light valve 20 is arranged below the λ / 4 plate 4.

As shown in FIG. 9, a desired light transmitting portion T and a desired non-transmitting portion N are spatially generated by a light valve 20 which is a liquid crystal. This pattern generation can be commanded by the processing device 10 and changed to a desired pattern. Therefore, by obtaining a video signal with the image sensor 9 while changing the pattern in the same manner as in the reflection type light valve, it is possible to obtain an image at one height at a high speed of 1 msec or less.

As in the second embodiment, the sample 2 is moved in the optical axis direction by a command from the processing system 10 to the light source 1 in order to obtain a three-dimensional (three-dimensional) shape. By repeating this, the above-described series of operations are performed, and images at each height are captured. The light source 1 is sequentially operated to store a plurality of images in the height direction, and three-dimensional information can be obtained from information in the height direction of the image having the highest luminance of the corresponding pixel. The acquisition of the above three-dimensional information can be realized within 33 msec of the TV rate.

As described above, a three-dimensional shape with high speed and high resolution can be obtained by using the light valve.

An example in which the confocal microscope of the present invention is applied for alignment of an exposure apparatus will be described with reference to FIGS.

FIG. 10 shows an off-axis alignment optical system AU fixed beside the projection optical system PO of the stepper by oblique lines. Any one of the above-described embodiments is arranged in the alignment optical system AU. W is the projection optical system PO
Is a wafer to be pattern-projected, and the alignment mark 2 on the wafer W corresponds to a sample in the description of the above embodiment. Further, the wafer stage 2A corresponds to the above-described sample stage. The stage 2A is moved so that the alignment mark 2 of the wafer W comes under the alignment optical system AU. By analyzing the three-dimensional shape of the alignment mark 2 in this state as described above, the deviation of the alignment mark 2 from a predetermined position to be aligned can be obtained.

For example, in the case of a periodic pattern in which the alignment marks 2 are arranged in a predetermined direction, three-dimensional shape information is electrically integrated in a direction perpendicular to the predetermined direction, and then converted to frequency information by performing FFT or the like in the predetermined direction. It is possible to measure as a phase difference how much the current arrangement (phase) of the periodic pattern deviates in a predetermined direction from the arrangement (phase) of the periodic pattern when it is at a predetermined position to be aligned.

Based on the displacement information, position information of the entire wafer W represented by the alignment mark 2 is obtained. Based on the position information, a control system (not shown) controls the stage 2A, and Exposure shots are sequentially arranged in an exposure area by the projection optical system PO to execute pattern projection transfer.

FIG. 11 shows an example in which the state where the resist R is applied to the alignment mark 2 on the wafer W is observed with the confocal optical system of the second or third embodiment used as the alignment optical system AU. I have. The optical system is partially omitted.

The confocal system using the BO element 7 as an optical system can move the best focus plane of the image in the optical axis direction by changing the wavelength (scanning) as described above. Now, the structure of the wafer W has a layer structure with a thickness of several μm including the resist R. As described above, when the wavelength of the semiconductor laser is scanned by about 2 nm, the optical axis direction is scanned by about 10 μm. It is large enough to observe.

As described above, when the present invention is applied to an apparatus for aligning the surface of a wafer, such as an exposure apparatus, the three-dimensional shape of the alignment mark on the wafer can be detected in real time, and the influence of asymmetry of the mark and uneven reflectance can be obtained. This makes it possible to achieve alignment that is less likely to be affected.

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described.

FIG. 12 shows a flow of manufacturing a semiconductor device (semiconductor chip such as IC or LSI, or a liquid crystal panel or CCP). In step 1 (circuit design), the circuit of the semiconductor device is designed. In step 2 (mask production), a mask on which the designed circuit pattern is formed is produced. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is referred to as a preprocess, and an actual circuit on the wafer is formed by lithography using the prepared mask and wafer. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer created in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 13 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to print a circuit pattern on the mask onto the wafer by exposure. Step 17 (development) develops the exposed wafer. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer. According to the present embodiment, it is possible to manufacture a semiconductor device having a higher degree of integration than before.

As described above, in the microscope, the BO
If a device and a variable wavelength light source are used, a three-dimensional image can be obtained at high speed. By combining this with a confocal optical system, a three-dimensional shape can be obtained more clearly and faster. Here, in order to increase the scanning speed, this is realized by providing a light valve means capable of independently controlling a pixel corresponding to a pinhole instead of a Nippow disk. This only controls the detection time of one pixel and selectively turns on / off the pixel even when the entire screen is not necessarily required.
High speed can be realized only by controlling ff.

In the above embodiment, not only the three-dimensional shape of the sample but also the two-dimensional shape of the sample consisting of components in the optical axis direction and one direction perpendicular to the optical axis using the image sensor as a one-dimensional element is described. It is also possible. In this case, the light valves only need to be arranged in one row in the corresponding direction.

In the above embodiment, the wavelength is changed.
That is, the image for each wavelength is time-divided, but light including a plurality of wavelengths is generated from the light source, and the light from the sample is separated into separate optical paths for each wavelength using a dichroic mirror or the like to separate image sensors. , That is, a configuration in which an image for each wavelength is spatially divided.

[0078]

As described above, according to the first aspect, it is easy to obtain an optical image of an object to be inspected at each image forming position by principle without separating a large member from being movable in the optical axis direction. Becomes possible.

Further, according to the second invention, such a configuration can be realized without generating a noise component and can be easily manufactured.

Further, according to the third aspect, such a configuration can be realized by simplifying the configuration on the imaging side.

Further, according to the fourth invention, such a configuration can be realized by using an easy-to-use light source.

According to the fifth aspect, an optical image can be obtained with higher accuracy.

Further, according to the sixth aspect, an optical image can be obtained at higher speed and with higher accuracy.

Further, according to the seventh aspect, such a configuration can be obtained with a small configuration, and further higher speed can be achieved.

Further, according to the eighth aspect, such a configuration can be obtained with a small configuration, and further higher speed can be achieved.

Further, according to the ninth aspect, it is possible to realize a configuration capable of measuring the shape of the object to be measured at high speed and with high accuracy without, in principle, requiring the large member to move in the optical axis direction.

Further, according to the tenth aspect, a configuration capable of measuring the three-dimensional shape of the test object at high speed and with high accuracy is realized.

Further, according to the eleventh aspect, such a configuration can be realized by simplifying the configuration on the imaging side.

Further, according to the twelfth aspect, such a configuration can be realized without generating a noise component and easily manufactured.

Further, according to the thirteenth aspect, it is possible to realize a configuration in which high-speed and high-accuracy position detection using an alignment mark can be performed without requiring a large member to move in the optical axis direction in principle.

Further, according to the fourteenth aspect, it is possible to realize a configuration which is less affected by the asymmetry of the mark and the unevenness of the reflectance.

Further, according to the fifteenth, seventeenth, and nineteenth aspects, a good exposure apparatus capable of performing simple, high-speed, and high-accuracy alignment is realized.

According to the sixteenth, eighteenth, and twentieth aspects of the present invention, it is possible to manufacture a high-density, high-density device by simple, high-speed, and high-precision alignment.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a microscope using a conventional Nippou disk.

FIG. 2 is an explanatory view of a Nippou disk in FIG. 1;

FIG. 3 is an explanatory diagram of shape measurement using a confocal microscope.

FIG. 4 is a schematic diagram of Embodiment 1 of the present invention.

FIG. 5 is an explanatory diagram of a BO element.

FIG. 6 is a schematic diagram of Embodiment 2 of the present invention.

FIG. 7 is an enlarged view of a main part of FIG. 6;

FIG. 8 is a schematic diagram of Embodiment 3 of the present invention.

9 is an enlarged view of a main part of FIG. 7;

FIG. 10 is a schematic diagram in which the present invention is applied to an alignment system of an exposure apparatus.

11 is an explanatory diagram of the alignment system in FIG.

FIG. 12 is a schematic flowchart of a device manufacturing method.

13 is a flowchart of a device manufacturing method using the exposure apparatus or the like in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light source 2 object to be observed 3 polarizing beam splitter 4 λ / 4 phase difference plate 5 polarizing means 6 imaging optical system 7 diffraction imaging optical element 8 imaging optical system 9 image sensor 10 processing device 20 light valve

Claims (20)

[Claims] 1. A light source capable of generating light of a plurality of wavelengths, an imaging optical system for forming an optical image of a test object illuminated by the light from the light source, and photoelectrically converting the optical image An imaging apparatus, comprising: an imaging element; wherein the imaging optical system includes a diffractive optical element. 2. An imaging apparatus according to claim 1, wherein said diffraction optical element is a binary optical element. 3. The imaging apparatus according to claim 1, further comprising a variable-wavelength light source for illuminating the object. 4. The imaging device according to claim 4, wherein said light source is a semiconductor laser. 5. An opening means having an aperture group, illuminating an object to be inspected with a light beam from the aperture group, and capturing an image of the object by the imaging optical system through the aperture group. The imaging apparatus according to claim 1, wherein a confocal optical system that forms an image on the element is configured. 6. An imaging apparatus according to claim 5, wherein said opening means is a light valve capable of independently controlling each of the openings constituting said group of openings. 7. The imaging device according to claim 6, wherein the light valve is a micro mirror device. 8. The imaging device according to claim 6, wherein the light valve is a liquid crystal device. 9. An image of the object to be inspected is formed via a diffractive optical element, whereby an image of the object to be inspected at each imaging position is separated by an imaging wavelength, and an image is obtained from the image at each imaging position. A shape measuring apparatus for measuring a shape including at least a component of an inspection object in a direction of an optical axis of an image. 10. The shape measuring apparatus according to claim 9, wherein a three-dimensional shape of the test object is measured from an image at each of the image forming positions. 11. An image of the test object at each image forming position is temporally separated by an image forming wavelength by illuminating the test object with changing a wavelength over time. The shape measuring device according to claim 9. 12. The shape measuring apparatus according to claim 9, wherein said diffraction optical element is a binary optical element. 13. An image of an alignment mark provided on an object is formed via a diffractive optical element, whereby an image of the alignment mark at each image forming position is separated by an image forming wavelength. A position detecting device that obtains position information of the object by using the image of the object. 14. Obtaining shape information of the alignment mark by using an image at each of the image forming positions, and obtaining positional information of the object by obtaining information on a shift of the alignment mark from a predetermined position from the shape information. The position detecting device according to claim 13, wherein: 15. An exposure apparatus using any one of the imaging devices according to claim 1 as an alignment mark detection unit. 16. A circuit is formed by using any one of the imaging devices according to claim 1 for detecting an alignment mark, positioning the wafer based on the detection, and performing pattern transfer. Device manufacturing method. 17. An exposure apparatus using any one of the shape measuring apparatuses according to claim 9 as an alignment mark detecting means. 18. A circuit is formed by using any one of the shape measuring devices according to claim 9 for detecting an alignment mark, positioning the wafer based on the detection, and performing pattern transfer. Method of manufacturing devices. 19. An exposure apparatus using any one of the position detection devices according to claim 13. 20. A circuit is formed by using any one of the position detection devices according to claim 13 and 14, positioning the wafer based on the position detection of the device, and performing pattern transfer. Device manufacturing method.