JPH10239015A - Surface position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exclude the influence of the distribution of reflectance by correcting the position information of an inspected surface obtained from a position detecting system, on the basis of the detection information from an optical characteristic detecting system. SOLUTION: A projecting optical system 140 is arranged in the optical path of light flux L2, L3 in front of an AOM 130, and a wafer W is placed in the position being conjugate to the AOM 130 with respect to the optical system 140. The two light flux L2 and L3 cause interference through the optical system 140 on the wafer W and form fringes of alternate line and space bands. Further, an imaging optical system 150 is arranged on the opposite side of the projecting optical system 140 with regard to the optical axis of a projecting optical system PL, and an array sensor 170 is arranged in the position being conjugate to the wafer W with regard to the optical system 150. The image of the frings on the surface of the wafer W is formed on the sensor 170. The lateral dislocation of fringes is measured from the information by means of the array sensor 170, and the position of the wafer in the vertical direction is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a surface displacement of a surface to be inspected, and more particularly, to focus detection of an optical system, for example, projection exposure for a surface to be inspected having a pattern on a base of a semiconductor device or a liquid crystal device. The present invention relates to a surface displacement detection device that detects a focal point of the device.

[0002]

2. Description of the Related Art As shown in FIG. 10, a focus position detecting device of a projection exposure apparatus for manufacturing a semiconductor device, a liquid crystal device, or the like, transmits light from a light source 1 to a light transmitting slit 3 via a condenser lens 2. Irradiation, the image of the light transmission slit 3 is projected obliquely onto the wafer surface W by the projection lens system 4, and the reflected light L 0 is projected through the imaging lens system optical system 5 to form the image on the wafer surface W. Slit 3
Is formed on the light receiving slit 6 or the sensor array. Then, the position of the wafer surface W in the vertical direction is detected by measuring the lateral shift of the center of gravity of the light amount of the slit image.

[0003]

According to the above focus position detecting apparatus, since the center of gravity of the quantity of reflected light from the wafer surface W is measured, the reflection of the wafer surface W by the semiconductor device circuit pattern or the like is performed. If the ratio is not uniform, the center of gravity of the reflected light moves, resulting in a detection error. Therefore,
In order to reduce such a detection error, as shown in FIG.
The patterns are projected such that the longitudinal directions of the slit image 12 and the stripe image 13 form an angle of 45 °. That is, the long detection slit 12 extends over the lines and spaces forming the circuit pattern, and covers these lines widely, thereby averaging the lines or the stripes 13 composed of a plurality of slits.
And averaged. However, the influence of the circuit pattern was not negligible.

Accordingly, the present invention provides a surface position detecting device which eliminates the influence of the reflectance distribution of the base of the surface to be detected and accurately detects the displacement of the surface to be detected, an exposure device having such a surface position detecting device, It is another object of the present invention to provide a method of manufacturing a semiconductor device that focuses a projection optical system while eliminating the influence of the reflectance distribution of a base on a substrate.

[0005]

In order to achieve the above object, a surface position detecting device according to the first aspect of the present invention, as shown in FIG. An irradiation system (110-142) for irradiating, and a position detection system (150-170) for detecting a position in a direction substantially perpendicular to the test surface by receiving light for position detection from the test surface.
An optical characteristic detection system for detecting optical characteristics of the surface to be inspected; and a position of the surface to be inspected from the position detection system based on information detected from the optical characteristic detection system. A correction system (180) for correcting information.

In the surface position detecting device according to the second aspect of the present invention, as shown in FIG.
The irradiation system includes a pattern member 2 having a predetermined pattern.
30, a first light source 210 that supplies the position detection light to irradiate the pattern member, and a projection optical system (240, 240) that projects the predetermined pattern onto the surface to be inspected to form an image. 241); the position detection system is re-formed by the imaging optical system (250, 252) for re-forming an image of a pattern formed on the surface to be inspected; First photoelectric detector 27 for photoelectrically detecting a pattern image
0; a second light source 242 that supplies illumination light for detecting optical characteristics of the surface to be inspected, and illumination optics that irradiates the illumination light to the surface to be inspected. System (2
41, 243), a light receiving optical system (250, 253) for receiving the illumination light from the surface to be detected, and a second photoelectric detector for photoelectrically detecting the illumination light via the light receiving optical system. 302. The predetermined pattern is, for example, a slit or a stripe.

Here, the pattern member is a light-transmitting slit plate or a mask on which a slit or stripe pattern is formed, and an image formed by projection onto the surface to be inspected by a projection optical system is formed by forming the slit or pattern. The image may be an image, or the pattern member may be a two-beam generating member such as a phase plate, and the image projected and formed on the surface to be inspected by the projection optical system may be an interference fringe formed by the two beams. . The image formed on the surface to be inspected is re-formed or imaged by the imaging optical system and detected by the first photoelectric detector.

With the above arrangement, the optical characteristics of the surface to be inspected are obtained because the optical characteristics detection system is provided, and the position of the surface to be inspected is determined based on the detected information on the obtained optical characteristics because the optical system has the correction system. The information is corrected.

Here, as in the invention according to claim 3, the optical characteristic detection system detects a reflectance distribution of the surface to be inspected; and the correction system is detected by the optical characteristic detection system. It may be configured to correct the position information of the test surface from the position detection system based on the information of the reflectance distribution. With this configuration, correction based on the most typical reflectance distribution among the optical characteristics of the test surface is performed on the position information.

In the surface position detecting device according to claim 2 or 3, as in the device according to claim 4 (see FIG. 1), the illumination optical system is shared with the projection optical system. A projection objective optical system; the light receiving optical system has a detection objective optical system shared with the imaging optical system; and the second light source is shared with the first light source. And the second photoelectric detector is configured to be shared with the first photoelectric detector; the pattern member 130 generates the predetermined pattern when detecting the position of the surface to be inspected;
A switching mechanism 131 for eliminating the predetermined pattern when detecting optical characteristics on the surface to be inspected may be provided.

In such a case, a projection objective optical system, a detection objective optical system, a light source, and a photoelectric detector are shared, and the pattern member generates a pattern when detecting the position of the surface to be inspected and detecting the optical characteristics. And a switching mechanism for elimination, a simple device can be realized.

In the surface position detecting device according to the second or third aspect, like the device according to the fifth aspect (FIG. 4,
5 and 6), the illumination optical system has a projection objective optical system that shares at least a part with the projection optical system; and the light receiving optical system shares at least a part with the imaging optical system. A first optical member (244, 4) for guiding the position detection light and the illumination light to the surface to be inspected via the projection objective optical system;
10, 540); the position detection system guides the position detection light to the first photoelectric detector via the detection objective optical system, and transmits the illumination light to the detection objective optical system. And a second optical member (251, 420) for guiding to the second photoelectric detector via the second optical member.

In such a case, since at least a part of the projection objective optical system and the detection objective optical system are shared,
The device can be simplified.

According to a fifth aspect of the present invention, at least one of the first and second optical members includes a shutter (410, 4).
20) (FIG. 8), or as described in claim 7, at least one of the first and second optical members is a light splitting member (244, 251, 41).
0, 420, 540).

In such a configuration, the shutter or the light splitting member guides the light for position detection and the illumination light to the surface to be inspected via the objective optical system for projection, or the light for detection of the position for the detection object. The light is guided to the first photoelectric detector via the optical system, and the illumination light is guided to the second photoelectric detector via the objective optical system for detection.

An exposure apparatus according to claim 8 is an exposure apparatus for exposing an exposure pattern formed on a mask R onto a photosensitive substrate W as shown in FIG. 1; Item 8. A surface position detecting device according to any one of Items 7, and a projection optical system PL for projecting an exposure pattern onto a photosensitive substrate. The surface position detecting device scans the surface of the photosensitive substrate with a surface to be inspected. The position of the photosensitive substrate is detected.

According to this structure, the surface displacement of the photosensitive substrate is detected by using the surface position detecting device according to any one of claims 1 to 7, so that before the exposure pattern is projected and exposed, Focusing can be achieved by eliminating the influence of the reflectance distribution due to the base of the substrate.

A method of manufacturing a semiconductor device according to claim 9 is a method of manufacturing a semiconductor device by exposing a photosensitive substrate to light; a step of providing a photosensitive substrate; and an exposing step formed on a mask. Detecting the displacement of the surface of the photosensitive substrate with respect to the image plane of the projection optical system for forming an image of the pattern; and detecting the image plane based on the surface displacement detected in the step of detecting the surface displacement. Adjusting the exposure pattern on the mask set at an optically conjugate position with respect to the image forming plane of the projection optical system and the projection optical system via the projection optical system. Projecting and exposing the photosensitive substrate to light; the step of detecting the surface displacement includes the step of irradiating the photosensitive substrate with light for detecting displacement, and the step of irradiating the photosensitive substrate. Light counter for displacement detection A step of detecting the position of light, a step of detecting the optical characteristics of the photosensitive substrate, and a step of detecting the position of the reflected light based on the information detected in the step of detecting the optical characteristics. Correcting the information.

According to such a method, the characteristic information of the substrate surface is obtained in the optical characteristic detecting step, and the correcting step is performed in the correcting step.
Since the information obtained in the reflected light position detection step is corrected, influences such as non-uniformity of the reflectance distribution of the base of the substrate are eliminated, and the focusing of the projection optical system is accurately performed.

As described above, according to the present invention, when detecting a surface displacement, when detecting an image of a slit or a stripe on the surface to be inspected, in addition to measuring the lateral displacement of the stripe or the like, the surface to be inspected can be uniform. The light amount distribution of the light receiving surface when the light is illuminated is measured, and the shape of the image on the light receiving surface such as the stripe is corrected based on the detected light amount, so that the position of the accurate stripe or the like can be measured.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding members are denoted by the same reference numerals, and redundant description will be omitted.

The principle of the present invention will be described with reference to FIG. In FIG. 9, for the sake of simplicity, it is assumed that the image of the stripe for displacement detection has a sinusoidal distribution. The horizontal axis is the position on the test surface,
The vertical axis is the amount of light. The graph of (a) shows the output of the measurement sensor array, and the graph of (b) shows the output of the correction sensor array for measuring the reflectance distribution of the test surface due to the influence of the circuit pattern formed on the base of the test surface. Show. (A) and (b)
Is data measured for the same region of the test surface.

The graph (c) shows the light quantity distribution after correction, which is a value obtained by dividing the output value shown in (a) by the output value shown in (b). Here, in the output value shown in (b), the light amount (maximum light amount) of a portion showing a uniform light amount is shown as a unit light amount 1.

Between the vertical lines in each graph, the individual sensors of the sensor array are shown. When the test surface has a non-uniform reflectance distribution as shown in the graph (b), the shape of the sine wave is distorted by the non-uniformity, the center of gravity of the light amount of the stripe moves, and a measurement error occurs. The situation is shown in the graph of FIG. The output value of the light amount shown in the graph of (a) is divided by the light amount distribution shown in the graph of (b) (c)
It can be seen from the graph of FIG. 7 that the sine wave has been restored and the influence of the underlying circuit pattern has been removed.

The first embodiment will be described with reference to FIG. In the figure, a substrate W such as a wafer as a test surface is placed at a position conjugate with the reticle R with respect to the projection optical system PL, and light from an illumination system (not shown) enters the reticle R,
The pattern on the reticle R is projected and exposed on the wafer W via the projection lens PL. In the present embodiment, the displacement of the wafer W is measured along the optical axis direction of the projection optical system PL, that is, in the vertical direction in the figure.

On the other hand, the condenser lens 120 and the acousto-optic device AO are placed in the optical path from the optical fiber 110 as the light source.
M130 are arranged in this order, and the optical fiber 110
The light emitted from the AOM 130 illuminates the acousto-optic element AOM 130 via the condenser lens 120 with Koehler illumination. The AOM 130, which will be described in detail later, acts as a diffraction grating and generates two light beams L2 and L3.

A projection optical system 140 is disposed in front of the AOM 130 and in the optical path of the light beams L2 and L3.
The wafer W is located at a position conjugate with the AOM 130 for 40.
Is placed. The two light beams L2 and L3 are projected by the projection optical system 140.
, Two light beams interfere with each other on the wafer W to form line-and-space (L / S) stripes. Alternatively, it may be considered that the diffraction grating forms an image. Here, the projection optical system 140 includes a condenser lens 141 and a projection objective lens 142.
To form a so-called telecentric optical system.

Further, an imaging optical system 150 is arranged on the side opposite to the projection optical system 140 with respect to the optical axis of the projection optical system PL, and an array sensor 170 is arranged at a position conjugate with the wafer W with respect to the imaging optical system 150. ing. Imaging optical system 1
The stripes on the wafer surface W are imaged on the array sensor 170 via 50. The lateral displacement of the stripes is measured from the information from the array sensor 170, and the vertical position of the wafer W is measured. That is, for example, when the wafer W is displaced in the direction away from the projection optical system PL,
The stripes shift laterally downward on the array sensor 170 in the figure.
The lateral displacement of the stripe is measured. Here, the imaging optical system 150
Includes a light receiving objective lens 151 and a condenser lens (imaging lens) 152, and constitutes a so-called telecentric optical system.

As shown in FIG. 3, the AOM 130 has a piezoelectric element 1 on one side end surface of a glass plate 134 as a medium.
32 are provided, and are modulated by a high-frequency signal 131A from a high-frequency AC signal generator 131. The glass plate 13
4 is vibrated by the piezoelectric element 132 to which the AC signal 131A is applied, and a compression wave is generated in the medium, and the piezoelectric element 13
2 is reflected at the other end face A opposite to the end face to which it is attached. Here, if the frequency of the AC signal 131A is appropriately determined according to the distance between both end faces, the vibration standing wave 1
33 are formed.

As described above, since the density is periodically generated in the glass plate 134, the light transmitted through the glass plate from the front surface to the back surface has a difference in optical path length. That is, the glass plate 134 functions as a stationary phase grating, and when the plane wave L1 is applied, emits two light beams of + 1st-order light L2 and −1st-order light L3. The diffraction efficiency of the ± 1st order light is theoretically easily 90
%, It may be treated as two luminous fluxes.

The two luminous fluxes are converted to the high frequency AC signal 131.
A is generated when modulated by A.
When not modulated, the plane wave L1 is AOM13
The light passes through 0 and is emitted as it is. Therefore, the high-frequency signal 131A is turned on and off at high speed, and the array sensor 1
70 is also measured in synchronism therewith, the stripes
When measuring the vertical position of the wafer surface W (FIG. 9, (a)), and when uniformly illuminating the wafer surface W and measuring the reflectance distribution of the wafer surface W (FIG. 9). ,
The signal output of (b) can be sent to the CPU 180 electrically connected to the high-frequency signal generator 131A and the array sensor 170.

Then, the CPU 180 is affected by the circuit pattern of the base of the wafer surface W, as shown in FIG.
9B is divided by the signal of the reflectance distribution of the wafer surface W as shown in the graph of FIG. FIG. 9, which is not affected by the pattern,
A signal as shown in the graph of (c) can be obtained.

FIG. 1 shows an optical path when the AOM 130 is ON. Next, FIG. 2 shows that the AOM 130 is OFF.
The optical path in the case of is shown. 1 and 2, the solid line is the chief ray,
The broken line indicates the optical path of the imaging light. As already explained, AO
When M is ON, the AOM and the wafer surface W
1 and 142, which are conjugate with respect to the projection optical system 140, the two light beams L generated by the standing wave of the AOM 130.
With 2 and L3, a stripe pattern is formed on the wafer surface W.

As shown in FIG. 2, the AOM 130
In the case of FF, A
Since the surface on which the OM is placed forms an image on the conjugate wafer surface W without being affected by the AOM, the wafer surface W is subjected to Koehler illumination. Therefore, at this time, the output of the correction system can be obtained on the array sensor 170 as described above.

The second embodiment will be described with reference to FIG. As in the embodiment of FIG. 1, a substrate W such as a wafer as a test surface is placed at a position conjugate with the reticle R in the lens system PL as the projection optical system. And the pattern on the reticle R is projected and exposed on the wafer surface W via the projection lens PL.

In the automatic focusing (AF) system of the present embodiment,
An optical fiber 210 as a light source, a condenser lens 220 arranged in the optical path thereof, and a slit prism 230 arranged in front thereof are arranged in this order. A stripe pattern 231 is formed on the surface of the slit prism 230 on the condenser lens side. The surface on which the stripe pattern is formed is illuminated by the illumination light L4 from the light source 210 via the lens 220, and is arranged so as to satisfy the Scheimpflug condition with the wafer surface W via an optical system described later. .

The surface on which the stripe pattern is formed and the wafer surface W
A condensing lens 240 and a projection objective lens 241 are arranged in the optical path between the lens 240 and 241. A stripe W13 is projected on the wafer surface W via these lenses 240 and 241.

A polarizing beam splitter (PBS) 244 is disposed in the optical path between the condenser lens 240 and the projection objective lens 241, and converts P-polarized light out of the light incident through the lens 240. Irradiation is performed on the wafer surface W.

On the other hand, an optical fiber 242 as a second light source,
The second condenser lens 243 is provided outside the above optical system, and the light L5 from the light source 242 is incident on the PBS 244 via the lens 243, and S2 of the incident light is reflected on the reflection surface of the PBS 244. The reflected polarized light is incident on the wafer surface W as the combined light L6 together with the P-polarized light from the lens 240.

As described above, via the PBS 244,
The P-polarized light on the wafer surface W is the light of the AF measurement system of the illumination light L4. The S-polarized light on the wafer surface W is a correction system light for the illumination light L5, and uniformly illuminates the wafer surface W.

In the optical path of the reflected light L6 from the wafer surface W, a light receiving objective lens 250, an imaging lens 252, and a light receiving prism 260 are arranged in this order. In the optical path between the light receiving objective lens 250 and the imaging lens 252,
A polarizing beam splitter (PBS) 251 is disposed, and light L that enters through a lens 250 on its reflection surface is provided.
6, the light from the AF measurement system reflected by the wafer 203 goes straight toward the light receiving prism 260, and the S-polarized light of the light L6, ie, the light from the correction system reflected by the wafer surface W. Is reflected and proceeds to a light receiving system of a correction system described later.

An index is formed on the surface of the light receiving prism 260 opposite to the lens 252. The light from the AF measurement system incident on the light receiving prism 260 via the lens 252 forms an image of the stripe pattern 231 on the surface of the prism 260 on which the index is formed. The surface of the prism 260 on which the index is formed and the wafer surface W satisfy the Scheimpflug condition.

The fringes formed on the surface of the prism 260 further form an image forming lens 290 by the action of the prism 260.
The image is formed on the CCD sensor 270 via a small angle while meeting the Scheimpflug condition at a small tilt angle. The image formed here is affected by the underlying circuit pattern on the wafer surface W and the like.

On the other hand, an imaging lens 253 and a light receiving prism 300 are arranged in this order on the optical path of the reflected light from the PBS 251. The reflected light from the image (uniform irradiation surface) on the wafer surface W illuminated by the light beam L5 of the correction system shines on the surface of the prism 300 opposite to the lens 253 via the lens 253 and shines on the wafer surface W. The image is formed so as to satisfy the proof condition.

Further, an image forming lens 301 and a CCD 302 are disposed in front of the prism 300. Like the AF measurement system, light incident on the surface of the prism 300 opposite to the lens 253 reduces the tilt angle. Lens 30
1 and form an image on the CCD 302 while satisfying the Scheimpflug condition.

The image on the CCD 302 is conjugate with the wafer surface W, and an image of the reflectance distribution of the wafer surface W that uniformly illuminates the wafer surface W is obtained. And, CCD270 and CC
The CPU 280 electrically connected to the D302
The stripe 231 from which the influence of the circuit pattern or the like is removed by dividing the output from 70 by the underlying circuit pattern or the like on the wafer surface W by the output from the CCD 302.
By measuring the lateral shift of the image, the vertical position of the wafer surface W can be detected.

Referring to FIG. 5, a third embodiment of the present invention will be described. The difference from the second embodiment in FIG.
Instead of the PBSs 244 and 251, the CPU 280 uses members 410 and 420 which transmit light as they are when a signal is applied such as a liquid crystal or the like, and which serves as a mirror to reflect light, and when another signal is applied or no signal is applied. Is 410
And 420 are turned ON and OFF simultaneously, and the sensors 270 and 30
In synchronization with 2, the correction is performed by dividing the signal of the AF measurement system by the signal from the correction system. In this case, since the PBS is not used, both the S-polarized light and the P-polarized light are guided to the wafer surface W and are less affected by the multiple interference of the resist. As a light source,
Use a halogen lamp.

Here, as the members 410 and 420, besides the liquid crystal plate, a multi-leaf rotating mirror as shown in FIG. 8 may be arranged with its reflection surface inclined with respect to the optical path. Also in this case, the mirror portions and the passing portions of the multi-leaf rotary mirrors 410 and 420 are used in synchronization. Note that FIG.
The case where the leaf mirrors are arranged at equal intervals around the rotation axis is shown. Any number of one or more leaves may be used, but it is preferable to arrange two or more leaves evenly in order to balance rotation. Note that it is possible to add a rotation balance weight to one leaf.

In the embodiment shown in FIG.
420 is a fixed half mirror, and the light sources 210, 2
42 may be alternately blinked. That is, when the light source 210 is turned on, the CPU 280 receives the signal from the light receiving element 270 of the AF measurement system, and when the light source 242 is turned on, receives the signal from the light receiving element 302 of the correction system. do it. In this case, the light source may be a halogen lamp or an LED, but a light source having a blinking speed as high as possible is used.

The fourth embodiment will be described with reference to FIG. Members common to those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals. In the figure, the AF measurement system is a light source LE
D510, condenser lens system 520, stripe pattern 5
30 are arranged in this order, and the light emitted from the LED 510 emits a stripe pattern 530 through the lens system 520.
Is illuminated uniformly.

The arrangement and operation of the projection optical system 140 composed of lenses, the wafer surface W, the projection optical system PL, the imaging optical system 150, and the array sensor 170 disposed in front of the stripe pattern 530 are shown in FIG. This is the same as the embodiment.

However, unlike the case of FIG. 1, a half mirror or a half prism 540 is inserted and arranged in the optical path between the stripe pattern 530 and the projection optical system 140.

The light from the stripe pattern 530 uniformly illuminated as described above transmits through the half prism 540, is projected on the wafer surface W by the projection optical system 140, and projects (images) the stripe pattern. It also has a lens system 150
The image is formed on the array sensor 170 by.

The correction system includes an LED 542 as a light source and a condenser lens system 541. Light from the LED 542 enters the half prism 540 via the condenser lens system 541, is reflected on the reflection surface thereof, and is described above. Along the same optical path as the light from the striped pattern 530
The wafer surface W is uniformly illuminated.

Since the wafer surface W and the array sensor 170 are arranged conjugately, the uniformly illuminated wafer surface W is imaged on the array sensor via the imaging optical system 150, and The reflectance distribution of the surface W can be measured.

The CPU 180 includes an array sensor 170, L
It is electrically connected to ED510, 542, LED
510 and 542 are alternately switched, and the array sensor 170 is synchronized with it. As a result, the measurement value of the AF measurement system and the reflectance distribution measurement value of the correction system are measured alternately, and the measurement value of the AF measurement system is corrected with the measurement value of the correction system to obtain the wafer surface W.
The position in the optical axis direction of the projection optical system PL, that is, in the vertical direction in FIG. 6, can be measured without the influence of the underlying pattern on the wafer surface W.

The LEDs 130 and 131 can have multiple wavelengths as shown in FIG. That is, in FIG. 7, LEDs 511, 512, 513,.
Are arranged side by side, and the half prisms 516, 5
17, 518... Are arranged correspondingly. The half prisms 516, 517, 518,... Are arranged such that the light reflected on each reflection surface overlaps on the same optical path. The light synthesized by overlapping is the L of the light source in FIG.
What is necessary is just to arrange | position so that it can be utilized as illumination light of ED510 or LED542.

The use of multiple wavelengths is advantageous because the amount of information on the light increases and is averaged, so that it is less susceptible to multiple interference on the wafer surface W.

Here, the half prisms 516, 517,
518 ... are LEDs 511, 512, 513 ...
May be a dichroic mirror corresponding to the above wavelength.
That is, for example, the dichroic mirror 516
The light of the wavelength of the ED 511 is reflected, and the LEDs 512 and 513 are reflected.
.. Are transmitted. .. And the LEDs 512, 513
... have a similar relationship. In this case, light loss can be suppressed.

In the embodiment described above, the wafer surface W
Although the output of the AF measurement system affected by the underlying circuit pattern and the like is divided by the output of the correction system, the same effect can be obtained even if the scale (magnification) of both is set to the same or appropriate scale and the difference is taken. can get.

In each of the embodiments described above, the position of the photosensitive substrate (wafer W) with respect to the image plane of the projection optical system PL is detected (the output of the AF measurement system is corrected based on the output of the correction system). After obtaining the output, the substrate stage (not shown) holding the wafer W as a photosensitive substrate is moved in the optical axis direction of the projection optical system PL to connect the surface of the photosensitive substrate to the projection optical system. The process proceeds to a focusing step of matching the image plane. Then, after this focusing step, the process proceeds to an exposure step (photolithography step). In this exposure process,
A reticle setting step of setting a reticle R on the object plane of the projection optical system PL, a substrate setting step of setting a wafer W as a photosensitive substrate on an image plane of the projection optical system PL, and setting of the reticle R and the wafer W After the step, a transfer step of illuminating the reticle R with the illumination optical system and projecting and transferring the pattern of the reticle R onto the wafer W as a photosensitive substrate via the projection optical system PL is included.

The wafer W that has undergone the above-described exposure process (photolithography process) is subjected to a developing process and then an etching process for removing portions other than the developed resist, and a resist for removing unnecessary resist after the etching process. It goes through a removal process. Then, the steps of exposure, etching, and resist removal are repeated to complete the wafer process. After that, when the wafer process is completed, in the actual assembling process, dicing is performed to cut and divide the wafer into chips for each baked circuit, bonding for providing wiring and the like to each chip, and package for packaging each chip Finally, a semiconductor device such as an LSI is manufactured through the respective steps such as ringing.

Although an example of manufacturing a semiconductor device such as an LSI by a photolithography process in a wafer process using an exposure apparatus has been described above, a liquid crystal display element,
Semiconductor devices such as thin-film magnetic heads and imaging devices (CCD, etc.) can also be manufactured.

[0064]

As described above, according to the present invention, a correction system for correcting the detection value of the position detection system is provided according to the optical characteristics of the test surface. However, it is possible to detect the displacement of the surface to be detected by eliminating the influence.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a focus position detection device using an AOM according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a case where AOM is OFF in FIG. 1;

FIG. 3 is a diagram illustrating a standing wave in an AOM.

FIG. 4 shows a second embodiment of the present invention, wherein A is
FIG. 3 is a schematic perspective view showing a focus position detection device that performs F signal and wafer reflectance distribution measurement.

FIG. 5 shows a third embodiment of the present invention;
FIG. 3 is a schematic perspective view showing a focus position detection device that performs AF signal and wafer reflectance distribution measurement by FF.

FIG. 6 is a schematic perspective view showing a focus position detecting apparatus for measuring an AF signal and a wafer reflectance distribution by switching LEDs according to a fourth embodiment of the present invention.

FIG. 7 is a diagram illustrating an example of a multi-wavelength light source.

FIG. 8 is a front view of an example of a multi-leaf mirror.

9A and 9B are diagrams for explaining the principle of the present invention, wherein FIG. 9A shows a detection signal of a fringe affected by the reflectivity distribution of a wafer, and FIG.
FIG. 7A is a diagram showing a signal obtained by measuring a reflectance distribution of a wafer, and FIG. 7C is a diagram showing a detected signal of a corrected fringe.

FIG. 10 is a schematic diagram illustrating an AF measurement system.

FIG. 11 is a diagram illustrating a state of a slit and a stripe pattern formed on a detection surface.

[Explanation of symbols]

 110 light source 130 AOM 131 high frequency AC signal generator 131A high frequency signal 140 projection optical system 150 imaging optical system 180 CPU 230 slit prism 231 stripe pattern 244, 251 PBS 260 light receiving prism 270 CCD 280 CPU 300 light receiving prism 302 CCD sensor 410, 420 Liquid crystal plate 510, 511, 512, 513 LED 516, 517, 518 Dichroic mirror 542 LED 530 Stripe pattern 540 Half prism R Reticle PL Projection optical system W Wafer surface

Claims (9)

[Claims] 1. An irradiation system for irradiating a position to be detected on a surface to be detected, and a position in a direction substantially perpendicular to the surface to be detected by receiving light for position detection from the surface to be detected. A surface position detection device comprising: a position detection system for detecting an optical characteristic; an optical characteristic detection system for detecting an optical characteristic of the surface to be inspected; and a position detection system based on detection information from the optical characteristic detection system. A correction system for correcting position information of the surface to be inspected; 2. An irradiation system comprising: a pattern member having a predetermined pattern; a first light source for supplying the position detection light for irradiating the pattern member; A projection optical system for projecting an image on a surface to form an image; the position detection system including an imaging optical system for re-forming an image of a pattern formed on the surface to be inspected; and the imaging optical system. A first photoelectric detector for photoelectrically detecting a pattern image re-formed by the first light source; the second light source for supplying illumination light for detecting the optical characteristics of the test surface;
An illumination optical system for irradiating the illumination light on the surface to be inspected, a light receiving optical system for receiving the illumination light from the surface to be inspected, and photoelectrically detecting the illumination light via the light receiving optical system The surface position detecting device according to claim 1, further comprising a second photoelectric detector that performs the operation. 3. The optical characteristic detection system detects a reflectance distribution of the surface to be inspected; and the correction system detects the position distribution based on information of the reflectance distribution detected by the optical characteristic detection system. 3. The surface position detecting device according to claim 1, wherein the surface position detecting device is configured to correct position information of the surface to be detected from a detection system. 4. The illumination optical system has a projection objective optical system shared with the projection optical system; the light receiving optical system has a detection objective optical system shared with the imaging optical system; The second light source is configured to be shared with the first light source, and the second photoelectric detector is configured to be shared with the first photoelectric detector; 4. The method according to claim 2, further comprising: a switching mechanism for generating the predetermined pattern when detecting the position of the test surface, and for eliminating the predetermined pattern when detecting the optical characteristics on the test surface; The surface position detecting device as described in the above. 5. The illumination optical system has a projection objective optical system at least partially shared with the projection optical system; and the light receiving optical system is at least partially shared with the imaging optical system. The irradiation system has a first optical member for guiding the position detection light and the illumination light to the surface to be inspected via the projection objective optical system; The position detection system guides the position detection light to the first photoelectric detector via the detection objective optical system, and guides the illumination light to the second photoelectric detection via the detection objective optical system. The surface position detecting device according to claim 2 or 3, further comprising a second optical member for guiding to the container. 6. The surface position detecting device according to claim 5, wherein at least one of the first and second optical members comprises a shutter. 7. The surface position detecting device according to claim 5, wherein at least one of the first and second optical members is constituted by a light splitting member. 8. An exposure apparatus for exposing an exposure pattern formed on a mask onto a photosensitive substrate; a surface position detecting apparatus according to claim 1; and an exposure pattern. And a projection optical system for projecting the photosensitive substrate onto a photosensitive substrate; wherein the surface position detecting device is configured to detect a position of the photosensitive substrate using a surface of the photosensitive substrate as a test surface. An exposure apparatus. 9. A method for manufacturing a semiconductor device by exposing a photosensitive substrate; providing a photosensitive substrate;
Detecting the displacement of the surface of the photosensitive substrate with respect to the imaging plane of the projection optical system that forms the image of the exposure pattern formed on the mask; and the surface displacement detected in the step of detecting the displacement of the surface Aligning the surface of a photosensitive substrate with the image plane, based on the following: an exposure pattern on the mask set at a position optically conjugate with respect to the image plane of the projection optical system and the projection optical system Projecting onto the photosensitive substrate via the projection optical system and exposing; exposing the photosensitive substrate to light for displacement detection, A step of detecting the position of the reflected light of the light for displacement detection irradiated in the step of irradiating, a step of detecting the optical characteristics of the photosensitive substrate, and the information detected in the step of detecting the optical characteristics. Based on the position of the reflected light The method of manufacturing a semiconductor device, which comprises a step of correcting the obtained information at.