JPH1073542A - Detector and detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a defect inspector for reticle in which the defect of phase difference in a phase shifter can be inspected for the entire region in a reticle in a short time simultaneously with detection of a translucent foreign matter. SOLUTION: In an arrangement for acquiring a differential interference image by causing interference of two luminous fluxes obtained by irradiating different positions of an object 8 with light, two kinds of differential interference image are obtained by varying the analyzer angle in two directions and the electrical difference thereof is outputted. Consequently, a first-order differentiation signal indicative of a phase differentiation image or a second-order differentiation signal different from the first-order differentiation signal is obtained. On the other hand, two luminous fluxes obtained by irradiating different positions of the object 8 with light are not caused to interfere with each other but respective images are acquired and the electrical difference between two kinds of image is outputted thus obtaining an intensity differentiation signal indicative of an intensity differentiation image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection apparatus, and more particularly to the detection of foreign matter and defects in a mask or a reticle (hereinafter referred to as a reticle) used in a process of manufacturing a semiconductor or a liquid crystal substrate, and a reticle with a phase shifter. To detect a defect of the phase shifter. In addition, the invention described in this specification also refers to a device for detecting the position of a reticle or other object provided on an opaque substrate using the same principle as the above-described defect inspection device. I do.

[0002]

2. Description of the Related Art A conventional binary reticle shifter phase difference amount defect inspection apparatus is disclosed in, for example, SPEI, Proceeding.
s series Volume 2254, "Photomask and X-Ray Mask te
Chnology, "p.294-301, the phase shifter portion to be inspected in the reticle is positioned within the field of view of the optical microscope, and the phase amount of one sampled point in the field of view is measured. There are things.

This is a kind of a phase shift amount measuring device for a reticle with a phase shifter. This apparatus can obtain only an inspection result for each sampled point for each inspection, and is unsuitable for inspecting defects in all of the reticle. Further, there has been no idea of detecting a defect having a phase difference amount and a foreign substance at the same time.

In recent years, as the degree of integration of a semiconductor device has been improved and the line width of a circuit pattern has been reduced, semi-transparent foreign substances which are considered to adhere to a reticle or the like in a cleaning step have been manufactured. It is thought to have an adverse effect when doing so. Meanwhile, as a foreign substance inspection apparatus, there is an apparatus that detects the presence or absence of a foreign substance by irradiating a substrate to be inspected with laser light and detecting scattered light generated when the foreign substance is present. However, it is very difficult for an inspection device that detects the presence or absence of a foreign substance using scattered light generated when a foreign substance is present to detect a translucent foreign substance.

In view of such a problem, the applicant of the present invention has disclosed in Japanese Patent Application No. Hei 7-215580 (which was not disclosed at the time of filing of the present application) a defect inspection such as an IC pattern or a foreign substance inspection using a differential interference microscope. Has been proposed. By using the present invention, foreign substances and defects existing on the reticle can be easily detected.However, at present, foreign substances and defects can be detected with higher sensitivity, and an image of an output pattern is used as a signal as much as possible. Inspection equipment that does not output is required. In this way, the user can make a judgment by not outputting information other than a defect or a foreign substance as much as possible, and by eliminating the need to judge whether or not the substance is a real foreign substance, it is possible to quickly detect a defect and
Foreign matter inspection can be performed.

[0006]

As described above, in view of such circumstances, the present invention inspects the phase shifters of all areas within the reticle for defects in the phase difference amount in a short time, It can also detect translucent foreign matter that interferes with the exposure of a reticle, and can be used as a foreign matter inspection device for a reticle without a phase shifter to obtain a reticle defect inspection device with a small signal output as a pattern image. Aim.

The present invention also refers to an apparatus for detecting the position of a reticle or other object provided on an opaque substrate using the same principle as the above-described defect inspection apparatus. .

[0008]

According to the present invention, a differential interference image obtained by interfering two light beams obtained by irradiating different positions of an object to be inspected with each other is obtained. Thus, two directions are obtained, and a difference is electrically output for the two types of differential interference images. By doing so, a primary differential signal indicating a phase differential image or a secondary differential signal having a signal waveform different from the primary differential signal was obtained. Further, the above-described images are obtained without interfering two light beams obtained by irradiating different positions of the inspection object with each other, and the two images are electrically output as a difference. As a result, an intensity differential signal indicating an intensity differential image was obtained.

As a result of analyzing the waveform of the intensity differential signal, the present inventors have found that the intensity differential signal is a composite signal of two signals of a primary differential signal and a secondary differential signal different from the primary differential signal. It was derived that. Therefore, the present inventors use the advantage of a first-order differential signal that outputs a waveform when a phase object present in an inspection object is present, and obtain the 1
An unnecessary secondary differential signal and a signal component due to a pattern image are removed from the secondary differential signal and the intensity differential signal to output only a signal relating to a defect or a foreign substance.

In other words, among the various signals obtained,
A signal component due to a foreign substance or a defect, a signal component based on a pattern image, and an unnecessary signal component of one of a primary differential signal and a secondary differential signal are included. A signal component due to a foreign substance or a defect is extracted from the primary differential signal and the two types of intensity differential signals.

Further, the present inventors have found that as another embodiment of the present invention, it is possible to pseudo-output a secondary differential signal component included in the intensity differential signal. Therefore, the secondary differential signal can be extracted without extracting only the secondary differential signal component from the two types of intensity differential signals, or without extracting the secondary differential signal component from the intensity differential signal and the primary differential signal. . It was found that the application can remove unnecessary secondary differential signals from the intensity differential signals.

Further, the present inventors have studied the signal components when a bright-field image obtained by the imaging optical system is extracted as an electric signal, and as a result, have found the following. A signal obtained by photoelectrically converting the bright-field image includes at least a first-order differential signal component, a second-order differential signal component, and a DC component. In addition, the second derivative signal has a portion having an optical step (for example, a portion having a structural step, or a portion having a different refractive index at an adjacent position; in other words, a portion having a certain phase difference relationship). Signal that irradiates adjacent positions, and changes the phase difference between the two lights obtained by reflecting or transmitting the respective positions) overshoots.

Therefore, when the magnitude relationship between the transmitted light and the reflected light is set to a predetermined relationship and the DC component is further subtracted, the edge of the object can be recognized. By utilizing this fact, it has been found that the edge of the object in the inspection object can be detected. Furthermore, the present inventors have conducted detailed studies on the primary differential signal, and as a result, have found the following regarding the primary differential signal. First derivative signal. At the edge of the object, it always has a symmetrical waveform,
By finding the center value of the waveform of the differential signal,
The position of the true edge of the object can be detected.

Therefore, a measuring device capable of detecting the position of the edge of the object can be obtained by acquiring the primary differential signal from the phase differential image or the intensity differential image. Furthermore, a primary differential signal representing only the position of the edge is obtained, and a difference in waveform between the primary differential signal used for detecting the position of the edge and the primary differential signal representing only the position of the edge is output. It was found that the position of a defect or foreign matter could be accurately detected.

By the way, the “difference” or “difference” used in the present specification means the following. For example, in the case of a signal based on an incident image and a signal based on a transmitted image, the waveforms generated by the same object are opposite to each other. When outputting the “difference” or “difference”, one of the waveform based on the signal based on the reflected image or the waveform based on the signal based on the transmission image is inverted (the positive / negative relationship is reversed). It shows that the difference between the waveform of the signal based on the image and the waveform of the signal based on the transmitted image is extracted. In addition, on the electric circuit, the sum of the signal based on the reflected image and the signal based on the transmitted image may be output.

Similarly, when a “difference” is obtained between signals obtained by incident light (or transmission),
This is to extract the difference between the waveforms of the respective signals. Note that, on an electric circuit, a difference between the respective signals may be output. Note that the signal waveform referred to here is the signal waveform when the horizontal axis indicates the position and the vertical axis indicates the signal intensity.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a description will be given of a defect detecting apparatus which detects foreign substances and defects as described above and does not output a pattern image patterned on a reticle. The principle of the present invention will be described while exemplifying a defect detection device in the first embodiment of the present invention. Further, a description will be given of defect detection apparatuses according to various embodiments.

[First Embodiment of the Present Invention]
FIG. 1 shows a schematic configuration diagram of a defect detection device according to a first embodiment of the present invention. This defect detection device can be roughly divided into two systems, an optical system and an electric processing system. First, the optical system will be described, and then the electrical processing system will be described.

The optical system of the defect detection apparatus according to the first embodiment of the present invention has the following configuration. A light source 1 for emitting laser light, a beam expander 2 for expanding a light beam of the light source 1, a light beam scanning optical member 26 for scanning light from the light source 1 on the inspection object 8, a relay lens 7, and a light source 1 A half mirror 3 for irradiating the object 8 with the light emitted from the light source, a Nomarski prism 13 for dividing the light from the light source 1 into two light beams, and shifting the light in a predetermined direction, and an objective lens A half mirror 65 for reflecting the object 8 to be inspected and splitting the light beam having the same light flux by the Nomarski prism 13 in two directions;
A quarter-wave plate 36 for adjusting a desired phase to the light beam made the same by the Nomarski prism 13, and the light component of two light beams reflected by the inspection object 8 in the light beam made the same by the Nomarski prism 13 Beam splitter 14 for causing polarization interference of light, and lens 15 for forming an interference image transmitted through polarization beam splitter 14
And a lens 16 for forming an interference image reflected by the polarization beam splitter 14.

A polarizing beam splitter 45 for splitting two light beams reflected by the inspection object 8 into respective directions with respect to one of the two light beams split by the half mirror 65, and a polarizing beam splitter. A lens 47 for forming an image of the light transmitted through the splitter 45 and a lens 46 for forming an image of the light reflected by the polarization beam splitter 45 are provided. Further, an optical system described below is provided for the light transmitted through the inspection object 8. The objective lens 42 for condensing the two light beams transmitted through the inspection object 8, the Nomarski prism 6 for converting the two light beams transmitted through the inspection object 8 into the same light beam, the mirror 64, and the inspection object 8 A polarizing beam splitter 62 for splitting the transmitted two light beams, and a lens 58 for imaging the light transmitted through the polarizing beam splitter 62
And a lens 55 for imaging the light reflected by the polarization beam splitter 62.

FIGS. 2 and 3 show the polarization state of light and the azimuth of each optical element in these optical systems. The operation of these optical systems will be described with reference to FIGS. By the way, regarding FIG. 3, the optical axis A
X is divided into two and displayed. Point A and point A 'are originally connected, and the arrow in the figure indicates the traveling direction of the light beam. FIG. 3 shows a case where the present invention is configured using an amplitude differential image (or a phase differential image) of reflection. In addition, these figures are described using only the principal ray for easy understanding.

The orthogonal coordinates (X1, Y1) to (X13, Y13) displayed near each optical element represent a plane orthogonal to the optical axis AX. Then, each X and each Y have the same orientation. In the following, the direction with respect to each coordinate axis is simply referred to as the direction with respect to the X axis and the Y axis. By the way, ray i0
Reference numeral 0 denotes a linearly polarized light ray, which is a light ray emitted from the light source 1. The light ray i00 is linearly polarized light having a polarization plane having an azimuth angle θ1 = 45 degrees with respect to the X1 axis, is reflected by the half mirror 3, and travels in parallel with the optical axis AX. The light beam reflected by the half mirror 3 is 2δ sheared (laterally shifted) on the surface (plane of the X2 and Y2 coordinates) of the inspection object 8 by the Nomarski prism 13 and the objective lens 10.
The light beam EO and the light beam OE are split into two light beams.
The light beam EO is linearly polarized light having a plane of polarization parallel to the Y3 axis, and the light beam OE is linearly polarized light having a plane of polarization parallel to the X3 axis. The Nomarski prism 13 is arranged near the focal position of the objective lens 10, and the Nomarski prism 13
The light beam OE and the light beam EO generated by the objective lens 10 are converted into substantially parallel light beams by the objective lens 10.

Then, the light beam OE and the light beam EO are
Is irradiated. By the way, the light beam OE and the light beam EO reflected by the surface of the inspection object 8 are converted into one light beam by the objective lens 10 and the Nomarski prism 13 again. The light beam reflected by the inspection object 8 and made into one light beam by the Nomarski prism 13 passes through the half mirror 3 and reaches the half mirror 65. A part of the light beam reaching the half mirror 65 is transmitted through the half mirror 65, and the rest is reflected by the half mirror 65.

The light transmitted through the half mirror 65 is 1/4.
The wave plate 36 is reached. The quarter-wave plate 36 has a fast axis ne, which is an optical axis, and a slow axis no, which is orthogonal thereto.
The direction of the slow axis no is set to 0 degree with respect to the X axis, and the direction of the early axis ne is set to 90 degrees with respect to the X axis. The component of the polarization plane parallel to the slow axis no has a phase delay of π / 2 with respect to the component of the polarization plane parallel to the fast axis ne. In the defect detection device according to the embodiment of the present invention, a 光線 wavelength plate capable of providing a phase difference according to each polarization plane is used, so that a light beam that is made into one light beam by the Nomarski prism 13 is used. A desired phase difference is provided between the EO component and the light beam OE component.

The relative phase difference α between the light beam EO and the light beam OE can also be adjusted by moving the Nomarski prism 13 in the X direction. In the case of the present embodiment, a 1/4 wavelength plate is fixed, and the Nomarski prism 1 is used instead.
3 is moved in the X direction to give a desired phase difference. Actually, when the light beams EO and OE irradiate a position where the surface of the inspection object 8 is completely flat, the phase difference between the reflected light beams OE and EO is adjusted to be zero. . By doing so, the light beam that has become one again by the Nomarski prism becomes linearly polarized light in the direction of the same polarization plane as the light beam i00, and enters the quarter-wave plate 36.

Next, the light beam transmitted through the quarter-wave plate 36 reaches the polarizing beam splitter 14. Of the light beams that have reached the polarizing beam splitter 14, θ2 with respect to the X axis
The component of the polarization plane parallel to the azimuth of = 45 degrees is transmitted, and the component of the polarization plane parallel to the azimuth of θ3 = 135 degrees with respect to the X axis is reflected. By the way, this polarization beam splitter 14
The light transmitted through is referred to as ir1, and the polarization beam splitter 1
The light reflected from 4 is light ray ir2. The light transmitted or reflected by the polarizing beam splitter 14 is reflected by the light beam OE.
And the light beam EO. The light transmitted through the polarization beam splitter 14 can be treated by the analyzer having an analyzer angle of 45 degrees in the same manner as the light in which the light beam OE and the light beam EO have polarization interference.
The light reflected by 4 can be treated by a analyzer having an analyzer angle of 135 degrees in the same manner as light in which the light beams OE and EO have polarization interference.

By the way, a part of the light beam in which the light beam EO and the light beam OE are made the same by the Nomarski prism 13 is reflected by the half mirror 65 and reaches the polarization beam splitter 45. Of the light beam that has reached the polarizing beam splitter 45, a component of the polarization plane parallel to the azimuth of θ4 = 0 ° with respect to the X axis is transmitted, and θ5 = 9 with respect to the X axis.
The component of the polarization plane parallel to the azimuth of 0 degree is reflected and reflected on the optical axis AX3.
Proceed along. The polarization beam splitter 45
Is transmitted through the ir11 and the polarizing beam splitter 4
The light reflected from 5 is ir22. Note that the polarization beam splitter 45 has the same operation as separating the light beam OE and the light beam EO that have been made into the same light beam by the Nomarski prism 13 again. Polarizing beam splitter 45
Is the light that can be treated equivalently to the substantial light beam OE, and the light that has reflected the polarization beam splitter 45 is light that can be treated equivalently to the substantial light beam EO.

Note that the rectangular coordinates (X4
, Y4) to (X7, Y7) indicate the direction of the polarization plane of each light beam. On the other hand, FIGS. 3A and 3B show light rays transmitted through an object. Of the light beams EO and OE generated by the Nomarski prism 13, the light beam EO and the light beam OE transmitted through the inspection object 8 are condensed by the objective lens 42, and are converged by the Nomarski prism 6 disposed near the focal position of the objective lens 42. It becomes i0. Then, the light beam i0 having the same light flux travels in the directions of the points A and A '. Then, the light beam i0 is reflected by the mirror 64
And is reflected by the polarization beam splitter 62.
In the polarization beam splitter 62, of the light beams that have reached the beam splitter 62, a polarization component parallel to the azimuth of θ8 = 0 ° with respect to the X axis is transmitted, and a polarization component parallel to the azimuth of θ9 = 90 ° with the X axis. The component is reflected. The light transmitted through the polarizing beam splitter 62 in this manner is referred to as a light ray it11,
The light reflected by the polarization beam splitter 62 is converted into a light beam it22.
And This light ray it22 travels along AX3. In addition, in this polarization beam splitter 62,
As in the case of the polarization beam splitter 45 described above, it has the same function as separating the light beam OE and the light beam EO that have been made into the same light beam by the Nomarski prism 6 again. The light that has passed through the polarization beam splitter 45 is light that can be treated equivalently to the substantial light beam OE, and the light that has reflected the polarization beam splitter 45 is light that can be treated equivalently to the substantial light beam EO.

In the first embodiment of the present invention, since the light beam OE and the light beam EO need not be polarized and interfere with each other to obtain an amplitude differential image described later, the Nomarski prism 19 is moved in the X direction. Therefore, there is no need to adjust the phase difference between the light beam OE and the light beam EO transmitted through the inspection object. However, in FIG. 3, when the inspection object 8 is uniform at the position where the light beam OE and the light beam EO are transmitted, the phase difference is adjusted so that the phase difference between the light beam OE and the light beam EO becomes an integral multiple of 2π. . Accordingly, in FIG. 3, the polarization plane of the light beam in which the light beam EO and the light beam OE have the same light flux is drawn as linearly polarized light of θ1 = 45 degrees.

The above is the description of the optical system of the defect detection device according to the first embodiment of the present invention. Next, an electric circuit system of the defect detection device according to the first embodiment of the present invention will be described. As shown in FIG. 1, a defect detection device according to a first embodiment of the present invention includes a polarization beam splitter 1
4, a photoelectric conversion element 18 that receives light reflected by the polarization beam splitter 14, and outputs a difference between a signal from the photoelectric conversion element 17 and a signal from the photoelectric conversion element 18. A differential amplifier 32,
A photoelectric conversion element 49 for receiving light transmitted through the polarization beam splitter 45; a photoelectric conversion element 48 for receiving light reflected from the polarization beam splitter 45;
9, a differential amplifier 19 that outputs a difference between the signal from the photoelectric conversion element 48, a photoelectric conversion element 59 that receives light transmitted through the polarization beam splitter 62, and a light reception element that reflects light reflected by the polarization beam splitter 62. Photoelectric conversion element 5
6, the signal from the photoelectric conversion element 56 and the photoelectric conversion element 59
And a differential amplifier 57 that outputs the difference from the signal from

Further, a signal from the differential amplifier 32, a signal from the differential amplifier 19, and a signal from the differential amplifier 57 are input, and a signal relating to whether or not a defect or a foreign substance exists in the inspection object is input. An output signal processing unit 24 is provided. In addition, a detection circuit 33 that determines whether or not the signal output from the signal processing unit 24 is within the range of the slice level determined by the main computer 20, and a stage on which the inspection object 8 is mounted A stage driving unit 38 for driving the light beam scanning optical member 26; a light beam scanning optical member driving unit 25 for driving the light beam scanning optical member 26; and a synchronous control for synchronizing the light beam scanning optical member driving unit 25 and the stage driving unit 38. The main computer 20 controls the control means 34 and the signal processing unit 24, designates a scanning range to the synchronization control means 34, designates a slice level to the detection circuit 33, and controls the entire defect detection apparatus. I have. The main computer 20 also controls phase difference adjusting means 41 and 23 for moving the Nomarski prisms 13 and 6 in the X direction.

The main computer 20 has:
The display device 21 and the interface 22 are connected. Next, assuming that the inspected object 8 is a reticle, the pattern images formed on the reticle are light rays ir1 and ir.
2. Processing procedures of signals obtained by receiving the light rays ir11, ir22, light rays it11, and light rays it22 will be described.

The OTF (Optical Transfer) of the lens
Function) will be described, and the step of the object to be observed is basically a one-dimensional structure. Therefore, in the following analysis, all the steps including the optical system are performed in one dimension. By the way, the phase difference added between the light beam OE and the light beam EO is α
The intensity distribution on the image plane when observing a defect-free reticle is considered as the reticle amplitude distribution as O (x).

Here, a one-dimensional model of the reticle circuit pattern is assumed as shown in FIG. The pattern of the reticle is considered to be a phase object with a change in reflectance due to the difference in height and the difference in reflectance between the substrate portion and the light-shielding portion. Therefore, from such an idea, a model as shown in FIG. 4A can be considered for the amplitude of the reflected light from the reticle 8. Further, the model of FIG.
It can also be expressed as shown in FIG. The model shown in FIG. 4B can be expressed as in Equation 1.

[0035]

O (x) = A (x) × exp (iφ) + B (1) In this equation (1), O (x) represents the magnitude of the amplitude at each position, and Is the DC component of the amplitude, A
(X) shows the AC component of the amplitude. Also, φ
Changes due to the difference between the reflected light at the substrate portion of the reticle 8 and the reflectance at the light shielding portion, and due to the phase difference that can be caused by the difference in the optical path length of the reflected light between the light shielding portion and the substrate portion. Value. I is an imaginary unit.

Incidentally, since the light beam OE and the light beam EO are sheared by 2δ, O (x +
δ), the ray EO can be represented as O (x−δ). Here, the intensity distribution on the image plane as a result of the interference between the light beam OE and the light beam EO is expressed by Expression 2.

[0037]

(Equation 2)

Here, PSF (x) is a point spread function (Point Spread Function) of the objective lens, and a phase difference α is a phase difference adjusting mechanism of a differential interference microscope, for example, a position adjustment of a Nomarski prism, a half-wave plate. The amount can be varied by a combination of a quarter-wave plate and a quarter-wave plate, a combination of a quarter-wave plate and a quarter-wave plate, or a Senarmon compensator. α
= + π / 2, -π / 2, the equations (3) and (4) are obtained.
Note that the expressions (3) and (4) are
7 and 8 show the characteristics of the signals related to the images acquired at 18. In this case, equation (3) corresponds to the signal acquired by the photoelectric conversion element 17, and equation (4) corresponds to the signal acquired by the photoelectric conversion element 18.

[0039]

(Equation 3)

[0040]

(Equation 4)

Here, when the difference between Expressions (3) and (4) is output, Expression 5 can be expressed as follows. Thus, in equation (5), A (x−δ) and A (x
+ Δ) is an equation having only a first-order term.

[0042]

(Equation 5)

Note that this equation (5) is
Further, the signal output from the photoelectric conversion element 18 is input to the differential amplifier 32, and the characteristics of the obtained output signal of the differential amplifier 32 are shown. Note that a signal having such a characteristic as the expression (5) will be described below as a primary differential signal or an amplitude differential signal (or a phase differential signal).

Incidentally, the result obtained by the equation (5) can be shown in FIG. FIG. 5 shows the amplitude of the light reflected by the substrate portion in the light EO reflected by the reticle 8 parallel to the real axis, and the amplitudes of the light OE reflected by the reticle 8 and the light reflected by the substrate portion by the light EO are orthogonal to each other. And the angles formed by the reflection amplitudes of the respective substrate portions are set to be π / 2. Taking such a model as an example, the light E obtained by the polarization interference between the light EO and the light OE is obtained.
The result of combining O and light OE can be represented as shown in FIG. The real axis and the imaginary axis in FIGS. 5 and 6 can be represented by orthogonal axes.

In this manner, the photoelectric conversion light receiving element 1
The signal in the interference image between the light EO and the light OE obtained in 7 is the same as the shape obtained by projecting the shape of the model in FIG. 6 onto a plane including the imaginary axis or the real axis, and can be represented as shown in FIG. . In the above-described calculation, the light EO and the light OE are divided into a prime part and a complex number part, and vectors at the amplitudes of the light EO and the light OE are combined to obtain the combined intensity. As described above, in the model using FIG. 6, a model as shown in FIG. 4B was not used, but a similar solution is finally obtained.

Next, the image received by the photoelectric conversion element 18 can be described as follows. In the photoelectric conversion element 18, Equation 4 is obtained, so that the result obtained as described above can be explained with the model drawn in FIG. 8. FIG. 8 shows the amplitude of the light reflected by the substrate portion in the light EO reflected by the reticle 8 in parallel with the real axis, and the amplitude of the light OE reflected by the reticle 8 and the amplitude of the light reflected by the substrate portion by the light EO are orthogonal to each other. And the angles formed by the amplitudes of the reflections of the respective substrate portions are shown as -π / 2. The result of combining such a model and the light EO and the light OE obtained by the polarization interference of the light EO and the light OE can be represented as shown in FIG.

Also, in this manner, the photoelectric conversion light-receiving element 1
The signal in the interference image of the light EO and the light OE obtained in 7 is the same as the shape obtained by projecting the shape of the model in FIG. 6 onto a plane including the imaginary axis or the real axis, and can be represented as shown in FIG. . The difference between the intensities I (π / 2) and I (−π / 2) obtained from the photoelectric conversion elements 17 and 18 is as follows:
The above equation (5) is obtained. When this is expressed by a model, it becomes as shown in FIG.

FIG. 11A shows the waveform of the signal output from the photoelectric conversion element 17, and FIG.
Is a waveform of a signal output from the photoelectric conversion element 18. Since the differential amplifier 32 outputs a signal indicating the difference between the signal of the photoelectric conversion element 17 and the signal of the photoelectric conversion element 18, a signal as shown in FIG. 11C is output. Thus, according to the position of the edge of the pattern on the reticle 8,
It is easy to see that the signal is output.

Since the output signal of the differential amplifier 32 is a function of the amplitude A (x) as shown by the equation (5), the output signal changes due to a change in the reflectance on the surface of the reticle 8 or a change in the step. Therefore, it is possible to detect the chromium pattern which is a phase object existing on the surface of the reticle 8, the presence / absence of foreign matter, and the position where the defective portion of the shifter of the phase reticle exists.

By the way, signals relating to other photoelectric conversion elements are as follows. First, the rays ir11 and ir
12 will be described. The image formed by the light beams ir11 and ir22 reflected on the reticle 8 shown in FIG. 2 is an image formed only by the light beams OE and EO, and
These are two bright field images shifted laterally by δ. Therefore,
Assuming that the signals output from the photoelectric conversion elements 48 and 49 are Ii (x + δ) and Ii (x−δ), they can be expressed as in the following equations (6) and (7).

[0051]

(Equation 6)

[0052]

(Equation 7)

The output signals from the photoelectric conversion element 48 and the photoelectric conversion element 49 are then input to the differential amplifier 19, and the output of the differential amplifier 19 at this time is the differential output of the reflection intensity. Si (x) is expressed as in equation (8).

[0054]

(Equation 8)

As can be seen from the equation (8), the reflection intensity differential amplification output Si (x) is represented by A (x−δ) and A (x−δ).
The term (x + δ) includes a second-order term and a first-order term. Incidentally, signals obtained from the photoelectric conversion elements 49 and 48 can be represented as shown in FIG. In this figure, the horizontal axis indicates the position x on the reticle 8, and the vertical axis indicates the intensity of the signal from each of the photoelectric conversion elements 48 and 49.

Incidentally, a line drawn by a dotted line 1201 in FIG. 12 represents a signal obtained by the photoelectric conversion element 48. A line drawn by a solid line 1202 in FIG. 12 represents a signal obtained by the photoelectric conversion element 49. These signals are input to the differential amplifier 19 and the photoelectric conversion element 48
And a difference from each signal of the photoelectric conversion element 49.

The signal output from the differential amplifier 19 has the waveform shown in FIG. As described above, in the output signal from the differential amplifier 19, a signal is output at the position of the pattern edge similarly to the differential amplifier 24. Also,
The waveform of the signal has the characteristic of the waveform of the secondary differential component different from the primary differential signal that cannot be seen in the differential amplifier 24. This secondary differential component has a signal waveform as shown in FIG.

The second-order differential component is calculated by the following equation (8).
A (x−δ) and A (x + δ) can be considered as components corresponding to the quadratic terms. Next, light transmitted through the reticle 8 will be described. By the way, when a one-dimensional model of the circuit pattern of the reticle is assumed as shown in FIG. 4C, the difference in thickness between the substrate portion and the light-shielding portion, It is considered that a difference in the refractive index and the like occurs. Therefore, a model as shown in FIG. 14A is conceivable for the transmitted light from the reticle 8. Further, the model of FIG.
It can also be expressed as shown in FIG. The model of FIG. 14B can be expressed as in Expression 9.

[0059]

(9) Ot (x) = √ (Kt) × A (x) exp (iφt) + Bt (9) where Bt in Expression (9) indicates a DC component of the amplitude distribution,
A (x) indicates the AC component. Also,
φt is a value that changes depending on the difference in transmittance and the difference in optical path length between the substrate portion and the light shielding portion of the reticle 8. √Kt represents the ratio of the AC component of the transmittance to the AC component of the amplitude reflectance from the reticle 8.

The image formed by the light beams it22 and it11 transmitted through the reticle 8 is shown in FIG.
And two transmitted bright-field images shifted laterally by 2δ from each other only by the light beam EO. Therefore,
The signals output from the photoelectric conversion element 56 and the photoelectric conversion element 59 can be Iit (x + δ) and Iit (x−δ), and equations similar to Equations (6) and (7) are obtained.

The output signals from the photoelectric conversion elements 56 and 59 are then input to the differential amplifier 57. The transmission intensity differential output Sit which is the output of the differential amplifier 57 at this time. (X) is expressed as in equation (10).

[0062]

(Equation 10)

As can be seen from equation (10), as can be seen, the transmission intensity differential output Sit (x) is A (x−δ) and A (x−δ) similarly to the reflection intensity differential amplified output Si (x). (X +
The term δ) includes a second-order term and a first-order term.
By the way, the above can be described as a model as follows. The signals obtained from the photoelectric conversion elements 56 and 59 can be represented as shown in FIG. In this figure, the horizontal axis indicates the position x on the reticle 8, and the vertical axis indicates the intensity of the signal from each of the photoelectric conversion elements 56 and 59.

Incidentally, a line drawn by a dotted line 1501 in FIG. 15 represents a signal obtained by the photoelectric conversion element 56. A line drawn by a solid line 1502 in FIG. 15 represents a signal obtained by the photoelectric conversion element 59. These signals are input to the differential amplifier 57 and the photoelectric conversion element 56
And a difference from each signal of the photoelectric conversion element 59.

The signal output from the differential amplifier 57 has the waveform shown in FIG. Thus, in the output signal from the differential amplifier 57, the signal is output at the position of the pattern edge similarly to the differential amplifier 19. Also,
The waveform of the signal has the characteristic of the waveform of the secondary differential component different from the primary differential signal that cannot be seen in the differential amplifier 24. This secondary differential component has a signal waveform as shown in FIG. This is considered to be the same as the intensity differential image at the time of the above-described epi-illumination proof, and the secondary differential component is a component corresponding to the second-order terms of A (x−δ) and A (x + δ) in Expression (10). Can be considered.

Note that a signal having such features as Expressions (8) and (10) will be described below as an intensity differential signal. By the way, in the first embodiment of the present invention, the signal processing unit 24 outputs a signal indicating a difference between the output signal from the differential amplifier 19 and the output signal from the differential amplifier 57. In the defect detection apparatus according to the first embodiment of the present invention, since it is desired to finally eliminate only the pattern edge portion from the output signal from the differential amplifier 19, the same primary differential component as that of the differential amplifier 32 is used. Only take out the signal.

Therefore, in contrast to the intensity differential signal of the reflection from the differential amplifier 19, the AC differential component of the complex amplitude distribution of the reticle 8 is different from the intensity differential signal of the transmission from the differential amplifier 57.
(Kt) times, the squared Kt is calculated by the differential amplifier 57.
Use the signal divided from the output of Note that an amplifier (not shown) is provided to make the output signal of the differential amplifier 19 and the output signal of the differential amplifier 57 have desired strengths. The magnitude of the signal relative to the reflected light is adjusted.

When the difference between the output signal from the differential amplifier 19 and the output signal from the differential amplifier 57 is output, in the embodiment of the present invention, the sum signal of each signal is output. . Because the image of the reticle pattern is
This is because the light and darkness and the position are opposite between the reflected light and the transmitted light. By the way, the difference signal between the output signal of the differential amplifier 19 and the output signal of the differential amplifier 57 can be expressed as in equation (11).

[0069]

[Equation 11]

By performing the above-described processing in the signal processing section 24, only the primary differential signal can be extracted from the reflected (emitted) intensity differential signal and the transmitted intensity differential signal. By the way, considering defect detection by simple binarization processing,
It is desirable that the error signal Es has a minimum (zero) circuit pattern on the reticle having no defect. Then, next, the signal processing unit 24 erases the signal of the pattern edge from the primary differential signal obtained from the intensity differential signal and the primary differential signal obtained from the differential amplifier 19, so that the defect exists. The following processing is performed so that the signal is output only when the operation is performed.

There are the following two methods for outputting a signal only when there is a defect existing in the reticle 8. First, the signal processing unit 24 outputs the difference between the primary differential signal obtained from the reflection intensity differential signal and the transmission intensity differential signal and the primary differential signal output from the differential amplifier 32. Thus, the error signal Es is obtained.

This error signal Es can be expressed as equation (12).

[0073]

(Equation 12)

In the second method, the primary differential signal obtained from the reflected intensity differential signal and the transmitted intensity differential signal in the signal processing section 24 and the primary differential signal output from the differential amplifier 32 are used. Is output to obtain a ratio signal Er. This ratio signal Er can be expressed as equation (13).

[0075]

(Equation 13)

Note that B, Bt, Kt, φ, and φt are constants, and a circuit pattern on a defect-free reticle is drawn with one type of pattern drawing material, and a step between the substrate portion and the light shielding portion has one type. If so, these constants do not change over the reticle. Therefore, if the type of the reticle to be inspected is determined, the values of the constants B, Bt, Kt, φ, and φt are substantially determined,
Based on these values and comparing the equations (5) and (10) by the method shown in the equation (12) or (13), only the defect can be easily extracted. Note that the error signal E
For s, a signal of "0" is output where no defect exists, and in the ratio signal Er, a signal of "1" is output where no defect exists.

The signal processing unit 24 adjusts the relative signal intensity between the reflected intensity differential signal Si, the transmitted intensity differential signal Sit, and the amplitude differential signal Sa by using an amplifier (not shown), thereby obtaining a defect. Binarization of detection can be achieved. Incidentally, adjustment of the relative gain of these differential signals is performed at a defect-free step portion of the circuit pattern on the reticle prior to defect inspection. Note that the relative gain adjustment between the differential signals can be automated by a computer 20 provided in the defect detection device. By the way, with regard to automation of gain adjustment, in the embodiment of the present invention, an operator first registers a non-defective portion in the reticle 8 and performs it. Also,
As another method, the luminous flux applied to the reticle 8 is made sufficiently larger than that at the time of inspection. By doing so, the sensitivity can be sufficiently reduced even if a defect exists. Then, the relative gain of each of the differential amplifiers 19, 32, and 57 before the start of the inspection can be automated by using a fixed position on the reticle 8, for example, near the coordinates of the alignment mark where the circuit pattern always exists. it can.

By the way, each time the type of the reticle 8 changes, the values of the constants B, Bt, Kt, φ, and φt have an allowable value accompanying a manufacturing error. Therefore, the signals of the differential amplifier 32, the signal from the differential amplifier 19, and the signal of the differential amplifier 57 are respectively set so that the actual constants for each reticle satisfy the equations (12) and (13). It is ideal to adjust the relative signal strength of In this case, the constants B, Bt, K
Without directly measuring the values of t, φ, and φt, using the defect-free circuit pattern portion of the reticle to be inspected for defect inspection,
It is preferable to adjust the relative signal strength so that the equations (12) and (13) are satisfied.

Incidentally, the defect detection apparatus according to the first embodiment of the present invention includes a detection circuit 33. In the defect detection apparatus according to the first embodiment of the present invention, actually,
Due to the influence of noise and the setting conditions of various members, even when the reticle 8 has no defect, the error signal Es does not become completely zero and the ratio signal Er similarly does not become completely one. Therefore, the error signal Es calculated by the signal detection circuit 24
The ratio signal Er is then input to a detection circuit 33 having a window comparator circuit for determining the slice levels of the error signal Es and the ratio signal Er, and the slice signal obtained as an appropriate value for the two signals is obtained. Level is set. A signal detected outside the range of the slice level is output as a defect of the reticle 8. By the way, in the defect detection device to which the present invention is applied, even if the slice level is set in this way, the slice level can be set to a lower value than in the conventional defect detection device. Therefore, there is an advantage that a highly sensitive defect detection device can be obtained.

The slice level of the window comparator circuit included in the detection circuit 33 is set to a level that does not cause erroneous detection of a reticle defect due to optical noise or electrical noise. The slice level of the error signal Es is set on each of the positive side and the negative side with respect to the error signal Es = 0. Further, the slice level of the ratio signal Er is set to a value larger than 1 and a value smaller than 1 with respect to the ratio signal Er = 1.

The detection circuit 33 is connected to a synchronizer 34. The synchronizing circuit 34 synchronously controls the respective movements of the laser beam scanning unit 26 during the inspection and the XY stage 37 for moving the reticle 8 in the XY directions. The laser beam scanning means 26 is driven via the actuator 25. The XY stage 37 is driven via an actuator 38. The synchronization signal generated by the synchronization device 34 is input to the detection circuit 33, and when a signal due to a foreign matter, a defect (contamination), or the like is output, the position of the signal can be specified.

Note that the result of the defect detection is
0 is displayed on the display means 2
1 can be displayed. In addition, even when a defect is detected at a plurality of locations on the surface of the reticle 8, a map of an inspection result in which the position of the defect is mapped can be displayed so that the defect location can be confirmed at a glance. Has become.

The error signal Es, the ratio signal Er, and the output values of the differential amplifiers 32, 19, and 57 are almost proportional to the degree of the defect. This is an effective method for displaying the degree. Therefore, in the defect detection device according to the first embodiment of the present invention, such a signal is displayed on the display 2.
In the case of displaying at 1, the error signal Es, the ratio signal Er, or the output values of the differential amplifiers 32, 19, and 57, the position information output from the synchronizer 34, and whether or not the slice line is outside the range. The information is output to the display in association with the information.

Further, in the computer 20, the signal processing section 24 adjusts the amplification gain in order to adjust the signal strength of the signal from each differential amplifier input to the signal detection circuit 24. In addition to controlling the synchronizer 34, the position of the Nomarski prisms 13 and 6 is adjusted, and the phase difference between the light beam EO and the light beam OE emitted from the Nomarski prism 13 can be adjusted.

By the way, the amplitude differential output Sa, which is the output of the differential amplifier 32, is expressed by the following equation (5). This shows the case where the gain of the differential output is maximum.
It is sufficient that the two interference images have a relationship of + and -θ as shown in FIG.

[0086]

[Equation 14]

However, as can be seen from Expression 14, the differential output has the maximum gain when θ = π / 2 + nπ (n is an integer), so that the phase difference between the light beam EO and the light beam OE is satisfied so that this relationship is satisfied. Is preferably adjusted. In the defect detection device according to the embodiment of the present invention, the maximum gain can be obtained by moving the Nomarski prism 13 in the X-axis direction by the computer 20.

The computer 20 allows the external operator to execute the initial setting of the inspection sensitivity, the inspection area, and the apparatus.
An interface 22 is provided for inputting the execution of the inspection and the like to the present defect detection apparatus. By the way, in the defect detection apparatus according to the first embodiment of the present invention, the reticle 8 scans the XY stage, so that the defect inspection can be performed even in a region outside the field of view of the objective lenses 10 and 42. This will be described with reference to FIG.

The inspection area D specified by the user indicates a partial area on the reticle R. In the defect detection device of FIG. 1, the inside of the visual field FV is an observable area. Reticle R is X
It is driven and scanned by a -Y stage. X
While moving the Y stage in the Y direction in FIG.
O and light OE are reciprocally scanned in the X direction, and the length of a region S that can be inspected only by scanning of a strip light having a width equal to the scanning distance L of the light OE and light EO is continuously enlarged in the Y direction. Thus, the entire inspection area D can be inspected.
Also, the entire inspection area D can be inspected by stepwise moving the reticle in the X direction to enlarge the area S in the X direction. In this case, since the direction of the shear where the light EO and the light OE are separated coincides with the scanning direction of the light, the scanning distance L is at most 2δ shorter than the diameter of the visual field FV by the amount of shear. In addition, it is desirable from the sampling theorem that the feed speed in the Y direction be equal to or less than 1/2 of the resolution limit. Similarly, when converting an image signal into time-series digital data, it is preferable to capture the image signal with a fineness equal to or less than half the resolution limit. Note that the scanning direction and the shear direction do not necessarily need to be matched.

The defect detecting device according to the first embodiment of the present invention is as described above. However, the present invention
The invention is not limited to this. For example, means for dividing light from a light source into light EO and light OE, and a reticle 8
A Nomarski prism was used as a means for combining light EO and light OE reflected and transmitted from the optical axis on the same optical axis. However, the present invention is not limited to a Nomarski prism as means for performing such a thing, and a Wollaston prism may be used. In short, it is an optical member having optical anisotropy and having birefringence, and using this birefringence, an object having a wedge shape is bonded so that the axes of light from a light source are perpendicular to each other. As a result, any material having a different refraction angle depending on the polarization direction of light may be used. By doing so, two lights having different polarization planes and coherent light can be generated.

The description made using the above model is based on the intensity of the point image on the image plane of the imaging type differential interference microscope. However, except for the depth of focus depending on the differential interference microscope of the laser scanning optical system,
If an objective lens with the same wavelength and the same NA is used, if the NA of the illumination optical system in the imaging type differential interference microscope or the NA on the detector side of the laser scanning optical system is appropriately set, the exact same differential interference image Is obtained.

The step of the object to be observed is basically 1
Because of the dimensional structure, the following analysis is performed in one dimension, including the optical system. Although the actual optical system is two-dimensional, in the following discussion, one-dimensional assumption is perfectly acceptable. To be implemented as an inspection device, the inspection time must be as short as possible. For this purpose, it is necessary to increase the brightness of the illumination light as much as possible. It is desired that a laser is the most suitable light source for this purpose, and that the inspection apparatus can be constituted by a differential interference microscope of a laser scanning optical system. The image obtained by the differential interference microscope of the laser scanning optical system becomes coherent imaging only when the NA on the detector side is “0”, and when the NA on the detector side is increased, the image becomes partially coherent and the NA on the detector side becomes the objective. When it is equal to the NA of the lens, incoherent imaging occurs. Therefore, an optical image by incoherent imaging can be easily obtained. Hereinafter, an optical image by incoherent imaging will be discussed.

Since the embodiment of the present invention is a laser scanning microscope following the optical system of a differential interference microscope,
The amplitude and phase information of the two beams reflected or transmitted from different positions on the inspection object are stored even if they are combined into one light beam by a light beam combining means (for example, a Nomarski prism). Therefore, a differential interference image can be obtained by a photoelectric conversion element installed at a position other than the image plane, for example, near the pupil conjugate plane. Therefore, in the defect detection device according to the embodiment of the present invention, the installation position of the photoelectric conversion element may be any position as long as it is located after the light beam combining means.

The image obtained by the differential interference microscope is an interference image of two images separated from each other by a shearing distance 2δ. Next, one-dimensional simulation results when an ideal objective lens is assumed using the defect detection device according to the first embodiment of the present invention are shown in FIGS.
9 The conditions of this simulation are as follows. Wavelength: 488 nm, illumination conditions: epi-illumination of incoherent illumination, N.I. A. = 0.4, 50 nm chromium oxide film on the reticle. The chromium oxide film has portions of 5 μm width and 1 μm width without chromium oxide, where the glass is exposed. The phase difference に よ る due to the step of the chromium oxide film is 2 × 50 nm / 488 nm × 360 ゜ =
73.77 °. The intensity reflectance of chromium oxide is 48
%, And the intensity reflectance of the glass was 4%.

The vertical axis of the graph indicates the intensity. Also,
k1 is a constant, and the peak values are aligned so that the subtraction result of the combined intensity differential signal and the amplitude differential signal becomes zero. The horizontal axis indicates the position, and the unit is μm. FIG. 18 shows a simulation signal when the portion without chromium oxide is 1 μm, and FIG.
The simulation signal in the case of m is displayed.

As can be seen from FIGS. 18 and 19, it has been confirmed by simulation that the error signal Es becomes completely zero. According to the present invention, since the image of the defect-free step can be completely erased, the resolution limit of the objective lens (= λ / NA (coherent illumination) to λ / 2NA)
(In-coherent illumination) Even if the object has a level difference of about or less, it is possible to detect a level difference and an abnormality in reflectance without any problem. Therefore, the ability to detect an abnormality on the reticle such as a foreign matter depends only on the level of the electrical noise if the edge of the circuit pattern of the reticle is vertical, and high detection sensitivity can be achieved.

Next, a description will be given of a defect detection apparatus according to another embodiment which is developed based on the first embodiment of the present invention. [Second Embodiment of the Invention] Next, a defect detection apparatus according to a second embodiment of the present invention will be described. FIG. 18 shows a configuration diagram of this defect detection apparatus. Note that the configuration denoted by the same reference numeral as FIG. 1 is the same as the configuration of the first embodiment of the present invention, and the description is omitted here.

The difference between the defect detection apparatus according to the second embodiment of the present invention and the defect detection apparatus according to the first embodiment of the present invention is that a configuration for acquiring an amplitude differential signal is used. １ ／ wavelength plate 36, polarizing beam splitter 14, condenser lenses 15 and 16, photoelectric conversion element 17,
18. Instead of the differential amplifier 32, a quarter-wave plate 60,
A polarization beam splitter 63, condenser lenses 52 and 53, photoelectric conversion elements 51 and 54, and a differential amplifier 50 are provided.
Further, in the defect detecting device according to the first embodiment of the present invention, a total reflection mirror 65a is provided at a position where the half mirror 65 is provided, and in the defect detecting device according to the second embodiment of the present invention, furthermore, total reflection is performed. In the defect detecting device according to the second embodiment of the present invention, the half mirror 6 is provided at a position where the mirror 64 is provided.
4a is provided.

As described above, in the defect detection apparatus according to the second embodiment of the present invention, the amplitude differential signal is obtained not by the reflected light from the reticle 8 but by the transmitted light. The other points are the same as those of the first embodiment of the present invention.
Therefore, since the amplitude differential output Sat, which is the amplitude differential signal, is obtained from the transmitted light of the reticle 8, the amplitude differential output Sat according to the second embodiment of the present invention is as shown in Expression 15. Note that the output of the equation (15) represents the characteristics of the output signal from the differential amplifier 50.

[0100]

(Equation 15)

As described above, in the second embodiment of the present invention,
For the amplitude differential output Sa in the first embodiment, √Kt
Multiplied by. Therefore, the error signal Est calculated in the second embodiment of the present invention is as shown in Expression (16).

[0102]

(Equation 16)

The error signal Ert calculated according to the second embodiment of the present invention is as shown in equation (17).

[0104]

[Equation 17]

In order to perform such signal processing, the signal processing circuit 24a according to the second embodiment of the present invention is different from the signal processing circuit 24 according to the first embodiment of the present invention in that an error signal E is obtained.
Although the operation contents of the st and the ratio signal Ert are different, other operations are the same as those of the signal processing circuit 24 according to the first embodiment of the present invention. FIGS. 21 and 22 show the polarization direction of each light and the like of the defect detection device according to the second embodiment of the present invention. FIG. 21 is a diagram showing an optical system for acquiring an intensity differential signal of epi-illumination, and FIG.
FIG. 3 is a diagram showing an optical system for acquiring various differential signals of transmitted illumination. These figures show the polarization state of light and the azimuth of each optical element.

Referring to FIG. 22, the optical axis A
X is divided into two and displayed. Point A and point A 'are originally connected, and the arrow indicates the traveling direction of the light beam. FIG. 11 shows a case where the present invention is configured using the amplitude differential image (or phase differential image) of transmission. In addition, in order to make explanation easy to understand, it demonstrates using only a chief ray. The rectangular coordinates (X1, Y1) to (X13, Y1) displayed near each optical element.
3) represents a plane orthogonal to the optical axis AX. Then, each X and each Y have the same orientation. In the following, the direction with respect to each coordinate axis is simply referred to as the direction with respect to the X axis and the Y axis.

Incidentally, the light beam i00 is a light beam emitted from the light source 1, as in the first embodiment of the present invention. This light beam i00 is reflected by the half mirror 3 and has an optical axis AX
The light travels in parallel with. The light reflected by the half mirror 3 is transmitted to the Nomarski prism 13 and the objective lens 10.
As a result, the light beam is split into two light beams, a light beam EO and a light beam OE displaced by 2δ on the surface (plane of the X2 and Y2 coordinates) of the inspection object 8. The ray EO is linearly polarized light having a plane of polarization parallel to the Y3 axis, and the ray OE is linearly polarized light having a plane of polarization parallel to the X3 axis. The Nomarski prism 13 is arranged near the focal position of the objective lens 10, and the light beam OE and the light beam EO generated in the Nomarski prism 13 are converted into substantially parallel light beams by the objective lens 10. Then, the configuration EO and the light beam OE reflect or transmit the reticle 8.

The light beam EO reflected from the reticle 8
And the light beam OE are made into the same light beam as in the first embodiment of the present invention, and reach the polarization beam splitter 45 via the mirror 65a. Subsequent steps are the same as in the first embodiment of the present invention, and a description thereof will be omitted. On the other hand, FIGS. 22A and 22B show light rays that pass through the object. Inspection object 8 out of light beams EO and OE generated by Nomarski prism 13
The light beam EO and the light beam OE that have passed through are collected by the objective lens 42 and become the same light beam i0 by the Nomarski prism 6 arranged near the focal position of the objective lens 42, as in the first embodiment of the present invention. . Then, the light beam i0 having the same light flux travels in the directions of the points A and A '. Then, the light ray i0 is reflected by the half mirror 64a, one on the polarization beam splitter 62 and the other via the quarter-wave plate 60 on the polarization beam splitter 6a.
Three. Since the polarization beam splitter 62 is the same as that of the first embodiment of the present invention, the description is omitted here.

By the way, the light incident on the quarter-wave plate 60 is set in the same manner as the quarter-wave plate 36 of the first embodiment of the present invention. Then, the light transmitted through the 波長 wavelength plate 60 enters the polarization beam splitter 63. by the way,
The polarization beam splitter 63 is the same as the polarization beam splitter 14 according to the first embodiment of the present invention, and the light beam transmitted through the polarization beam splitter 63 is a light beam i.
It becomes t1 and becomes linearly polarized light of 45 degrees on the X axis. The light beam reflected by the polarization beam splitter 63 becomes a light beam it2 and becomes a linearly polarized light having an azimuth of 135 degrees with respect to the X axis. And
The reflected light of the polarization beam splitter 63 is received by the photoelectric conversion element 51, and the transmitted light is received by the photoelectric conversion element 54. The output signals obtained from the photoelectric conversion elements 51 and 56 are differentially output by the differential amplifier 50 to obtain an amplitude differential signal of the light transmitted through the reticle 8.

The azimuth of each optical element is set as shown in FIGS. 21 and 22. The azimuth with respect to the X axis about the optical axis AX is 1/4 when the Y axis direction is positive.
The optical axis of the wave plate 60 is 0 degree, the Nomarski prism 6,
The direction of the wedge of the Nomarski prism 13 is 0 degree, and the analyzer angle (θ6) of the polarizing beam splitter 63 is +45.
The analyzer angles (θ4, θ6) of the polarization beam splitter 45 and the polarization beam splitter 62 are set to 0 degree.

An error signal Es or a ratio signal Er is obtained by the signal processing unit 24 from the signal regarding the reflection intensity differential image and the transmission amplitude differential image and the signal regarding one transmission amplitude differential image thus obtained. In the same manner as in the first embodiment of the present invention, an abnormal portion such as a defect can be detected. [Third Embodiment of the Present Invention] Next, a defect detecting apparatus according to a third embodiment of the present invention will be described. Third of the present invention
The defect detection device according to the embodiment is a combination of the defect detection device according to the first embodiment and the defect detection device according to the second embodiment. FIG. 23 shows a defect detection apparatus according to the third embodiment of the present invention. By the way, the configuration denoted by the same reference numeral as FIG. 1 is the same configuration as the defect detection device according to the first embodiment of the present invention, and the configuration denoted by the same reference numeral as FIG. The configuration is the same as that of the defect detection device according to the embodiment. Note that the defect detection device according to the third embodiment of the present invention has a configuration other than the signal processing unit 24b.
Since the configuration has been described in the first embodiment and the second embodiment, the description of the configuration here is omitted.

The characteristic part of the third embodiment of the present invention is the signal processing section 24b. In the defect detection device according to the third embodiment, the configuration for obtaining the amplitude differential signal is obtained from both the light transmitted through the reticle 8 and the light reflected from the reticle 8. The configuration for obtaining the amplitude differential signal of the reticle 8 by the reflected light is 、
Wave plate 36, polarizing beam splitter 14, condensing lenses 15, 16, photoelectric conversion elements 17, 18 and differential amplifier 32
It is. The configuration for obtaining an amplitude differential signal with respect to light transmitted through the reticle 8 is a quarter-wave plate 60, a polarizing beam splitter 63, condenser lenses 52 and 53, photoelectric conversion elements 51 and 54, and a differential amplifier 50. .

In the third embodiment of the present invention, the signals from the differential amplifiers 19, 57, 32, 50
Receive with b. Next, from the signals of the differential amplifiers 19 and 57 and the signal of the differential amplifier 32, the error signal E
The signal processing unit 24b calculates s and the ratio signal Er expressed by Expression 13. Further, in the signal processing unit 24b, the differential amplifier 1
The error signal Est expressed by Expression 16 and the ratio signal Ert expressed by Expression 17 are calculated from the signals from the signals 9 and 57 and the signal of the differential amplifier 50.

The error signal E is output from the signal processor 24b.
By taking the sum of the absolute value of s and the absolute value of the error signal Est, and also by taking the product of the absolute value of the ratio signal Er and the absolute value of the ratio signal Ert in the signal processor 24b, the reliability is obtained. High defect determination is possible. In addition, the error signals Es and Est are separately output as a result of the presence or absence of a defect based on the slice level as they are, and if one of them exceeds the range of the slice level, an “OR logic” that determines that there is a defect is output. The presence / absence of a defect may be displayed by using this. Alternatively, the presence or absence of a defect may be indicated by using “AND logic” that determines that there is a defect when both the error signals Es and Est exceed the slice level range.

FIGS. 24 and 25 show the polarization state of light and the azimuth of each optical element in the optical system of the defect detection apparatus according to the third embodiment of the present invention.
FIG. 24 is a drawing showing the reflected light of the reticle 8, and is the same as FIG. FIG. 25 shows the transmitted light of the reticle 8 and FIG.
Same as 2. Further, since the arrangement relationship of each component is the same, the description is omitted here.

Note that, in these embodiments of the present invention,
An amplitude differential image that can be detected by the amplitude differential signal Sa has a high detection capability for a phase object. In addition, the phase change due to the defect of the reticle is larger when the amplitude differential signal that detects the reflected light from the reticle is output. However, when the reticle to be inspected is a phase shift reticle such as a Levenson type, the possibility of detecting a pseudo defect is reduced by using the amplitude differential signal obtained by detecting the transmitted light from the reticle. Since there is such a difference in whether the differential amplitude signal is obtained by the reflected light from the reticle or the differential amplitude signal by the transmitted light from the reticle, it is very difficult to change the detection logic for each reticle type. It is valid.

In the above-described embodiment of the present invention, the defect detecting apparatus according to the first to third embodiments of the present invention employs the Nomarski prism for adjusting the phase difference between the light EO and the light OE. 13 and 6 were adjusted by moving in the direction crossing the optical axis direction. However, the present invention is not limited to this, and the phase difference between the light EO and the light OE may be adjusted by combining a quarter-wave plate and a polarizer rotatable around the optical axis.

In the above embodiments, the description has been given based on the laser scanning type. However, the present invention may be applied to an imaging type apparatus using a halogen lamp. In this case, the illumination light is different from the laser beam spot, and collectively illuminates the objective lens, uses an image sensor with multiple pixels for the photoelectric conversion element, and places the image sensor at an imaging position conjugate to the object. There is a need to. [Fourth Embodiment of the Present Invention] In the above-described embodiment of the present invention, the first-order differential component obtained from the intensity differential signal and
From the signal component of the second derivative component, a sum signal of the intensity differential signal of reflection and the intensity differential signal of transmission is generated to obtain a first differential signal. However, since the ratio between the secondary differential signal component and the primary differential signal component is different between the incident-light differential image and the transmitted differential image, when obtaining the sum signal of the reflected-light intensity differential signal and the transmitted-light intensity differential signal, By changing the gain given to each signal, a second-order differential signal can be obtained.

Therefore, the present inventors have invented a defect detection apparatus in which a secondary differential signal is extracted from an intensity differential signal due to incident light and an intensity differential signal due to transmission. An embodiment of the invention will be described below. Incidentally, the defect detection apparatus according to the fourth embodiment of the present invention has the same configuration as the defect detection apparatus according to the first embodiment of the present invention except for the signal processing unit 24 only. I have. Therefore, the figure numbers given below are the same as the numbers shown in FIG.

In the description of the fourth embodiment of the present invention, only the difference between the signal processing units 24 will be described. In the fourth embodiment of the present invention, a secondary differential signal is obtained from the primary differential signal obtained from the differential amplifier 32 and the intensity differential signal output from the differential amplifier 19. Actually, a first differential signal obtained from the differential amplifier 32 is added to a first differential amplifier provided in the signal processing unit 24,
The intensity differential signal output from the differential amplifier 19 is input. At this time, the intensity differential signal is once input to the amplifier so that the primary differential signal component of the intensity differential signal and the primary differential signal output from the differential amplifier 32 have the same value.
Then, the intensity differential signal is transmitted to the first
, And outputs a difference from the first-order differential signal output from the differential amplifier 32.

At the same time, the incident intensity differential signal output from the differential amplifier 19 and the transmitted intensity differential signal output from the differential amplifier 57 are input to the second differential amplifier in the signal processing unit 24. You. Before inputting each signal to the second differential amplifier in the signal processing unit 24,
Each signal is input to an amplifier having a predetermined amplification factor so that the peak value of the next differential signal component becomes the same. In this way, the primary differential signal components of the incident intensity differential signal and the transmitted intensity differential signal have the same peak value.

As described above, the first in the signal processing unit 24
Second differential signals are obtained from the differential amplifier and the second differential amplifier, and the peak values of the output signal of the first differential amplifier and the output signal of the second differential amplifier are made uniform. By outputting the difference between the waveforms and outputting the error signal Es, or by outputting the ratio of the signals and outputting the ratio signal Er, it is determined whether or not the reticle 8 has a defect. Has been detected.

Next, these operations will be described with reference to signal waveforms obtained by simulation. First, a reticle model used in performing the simulation is shown in FIG. FIGS. 26A and 26B show a 50 nm chromium oxide film on a transparent glass substrate. The chromium oxide film has portions of 5 μm width and 1 μm width without chromium oxide, where the glass is exposed. The phase difference に よ る due to the step of the chromium oxide film is 2 × 50 nm / 488 nm × 360 ゜ = 7
3.77 °. The intensity reflectance of chromium oxide is 48%,
The intensity reflectance of the glass was 4%. FIG. 26 (a)
In FIG. 26, the portion without chromium oxide has a width of 1 μm.
In (b), the portion without chromium oxide has a width of 5 μm.

By the way, the simulation waveform shown in FIG. 26B was used. By the way, FIG.
Reference numeral 7 denotes an output signal S obtained by inputting the intensity-differential intensity signal Si of the epi-illumination output from the differential amplifier 19 to the amplifier.
i * K4 waveform 2701, reflected amplitude differential signal Sa waveform 2702 output from differential amplifier 32, and first secondary differential which is the difference between the intensity differential signal Si * K4 and the amplitude differential signal Sa. This is a simulation of the signal Sa-Si * K4 waveform 2703.

FIG. 28 shows the intensity differential signal Si * of the epi-illumination.
The output signal St * K5 waveform 2704 obtained by inputting the K4 waveform 2701, the transmission intensity differential intensity signal St output from the differential amplifier 57 to the amplifier, the reflected intensity intensity signal Si * K4, and the transmission A second secondary differential signal (Si * K4 + St) which is a sum signal of the intensity differential signal St * K5
This is a simulation of the waveform 2705 of * K5).

In FIGS. 27 and 28, the horizontal axis indicates coordinates relating to the position of the reticle model, and the vertical axis indicates the magnitude of the signal. The edges of the chromium oxide pattern are -2.5 and 2.5 on the horizontal axis in FIGS.
Position. By the way, two second derivative signals, Sa-S
FIG. 29 shows a comparison between the respective waveforms of i * K4 and Si * K4 + St * K5. In this way, Sa-
Si * K4 and Si * K4 + St * K5 have similar waveforms. The amplification gains of these two signals are changed so that the peak values match, and the sum of the two is [(Sa−Si * K4) + (Si * K4).
+ Sit * K5) * K6], it becomes completely zero as shown in FIG.

Note that the waveform shown in FIG.
The second derivative signal waveform 2705 and the first second derivative signal Sa
−Si * K4 and the second secondary differential signal (Si
* K4 + Sit * K5) * The sum of the waveform 2706 of K6 and the two secondary differential signals [(Sa-Si * K4) + (Si
* K4 + Sit * K5) * K6].

As described above, by using the same configuration as that of the first embodiment of the present invention and making the signal processing section 24 perform the signal processing shown in the fourth embodiment of the present invention, It is possible to prevent the output of the signal of the edge portion of the pattern. [Fifth Embodiment of the Invention] Next, a defect detection apparatus according to a fifth embodiment of the present invention will be described. The defect detection device according to the fifth embodiment of the present invention has a configuration shown in FIG. Compared with the defect detection device according to the first embodiment of the present invention, a half-wave plate HW rotatable around the optical axis AX by the actuator AT is added, and the processing method of the signal processing unit 24 is changed. It is a signal processing unit 24e.

By the way, the polarization beam splitter 14
Is set to an analyzer angle (direction of the transmission axis) of 45 ° with respect to the polarization plane of the light beams OE and EO as shown in the first and second embodiments of the present invention.゜ When rotated, the linearly polarized light OE and EO can be extracted without causing interference, resulting in two bright field images, and the output of the differential amplifier 32 becomes an intensity differential signal. Note that, under conditions other than these two angle conditions, an image is obtained in which the amplitude differential signal and the intensity differential signal are mixed, and the amplitude differential signal and the intensity differential signal are strengthened or weakened at a cycle of 180 ° of the analyzer angle.

In the structure shown in FIG. 31, the half-wave plate H
Rotating W is equivalent to rotating the analyzer angle at twice its angle. When the analyzer angle is adjusted, the amplitude differential image and the intensity differential image weaken each other, so that only the secondary differential image can be finally left. Therefore, the differential amplifier 32 in FIG. 31 has a configuration in which the half-wave plate can be rotated so as to output the second-order differential signal.

As described above, the half-wave plate HW and the half-wave plate
With the provision of the actuator AT, which is a wave plate rotating mechanism, the differential amplifier 32 outputs a secondary differential signal. The actuator AT is controlled by the computer AT, and can be adjusted based on the signal obtained from the signal processing unit 24e so that the half-wave plate HW has an optimum angle.

FIG. 32 is a circuit diagram of a preferred signal processing unit 32 in the defect detection apparatus according to the fifth embodiment of the present invention. Those given the same reference numerals in FIG. 32 as those in FIG. 31 are the same members. By the way, the photoelectric conversion elements 17, 18, 48, 49, 56, 59
Are input to preamplifiers A in which the gains can be adjusted provided in the differential amplifiers 32, 19, and 57, respectively. Each of the photoelectric conversion elements 17, 18, 4
The outputs of 8 and 49 are amplified with an appropriate amplification gain. Next,
Outputs from the photoelectric conversion elements 17 and 18 are input to a differential amplifier circuit D1 in the differential amplifier 32. Similarly, outputs from the photoelectric conversion elements 48 and 49 are input to a differential amplifier circuit D2 in the differential amplifier 19, and outputs from the photoelectric conversion elements 56 and 59 are input to a differential amplifier circuit D3 in the differential amplifier 57. Is done.

Here, the differential amplifier circuit D1 outputs a secondary differential signal from the signals from the photoelectric conversion elements 17 and 18. Further, the differential amplifier circuit D2 outputs an intensity differential signal in the reflected light from the reticle 8, and the differential amplifier D3 outputs an intensity differential signal in the transmitted light from the reticle 8. Next, the output signals of the differential amplifier circuits D2 and D3 are input to a balance adjustment circuit Bal in the signal processing unit 24e, where D2 and D3 are output.
3. The peak values of the output signal from 3 are aligned. Then, the intensity differential signal from the differential amplifier 19 and the intensity differential signal from the differential amplifier 57 are added by the waveform synthesis circuit Mix, and a secondary differential signal is output.

Next, the secondary differential signal obtained by the differential amplifier 32 and the secondary differential signal obtained by the waveform synthesizing circuit Mix in the signal processing circuit are adjusted in relative intensity, and then subjected to signal modulation. The difference is subtracted by the differential amplifier circuit D4 in the logical circuit 24e. This becomes the aforementioned error signal Es. The error signal Es is input to a window comparator Wcom to which signals of two positive and negative slice levels Th.H and Th.L are input. The error signal Es is binarized by the window comparator Wcom and becomes a Det signal indicating presence / absence of foreign matter.

As for the detection of the size of the foreign matter,
The outputs of the differential amplifier circuit D1 and the waveform synthesizing circuit Mix are used. These are selected by the signal selector SS. The signal selector SS may be, for example, a maximum value output circuit that selects and outputs a stronger signal strength, or may be a minimum value output circuit. This should be chosen according to the intended use.

The circuit in FIG. 28 can be applied to the first embodiment of the present invention as it is, in which case the differential amplifier circuit D1 and the waveform synthesizing circuit Mix use the amplitude differential image (primary differential image). Needless to say, the output is In the defect detection device according to the fifth embodiment of the present invention, the relative intensity between the output of the waveform synthesizing circuit Mix and the output of the differential amplifier circuit D1 is adjusted.
The adjustment is performed by the balance circuit Bal and the preamplifier A in the differential amplifier. Second Embodiment of the Present Invention] [Fifth Embodiment of the Present Invention] Next, a defect detecting apparatus according to a fifth embodiment of the present invention will be described. FIG. 27 shows a defect detection apparatus according to the fifth embodiment of the present invention.
In addition to the defect detection device shown in the fourth embodiment of the present invention, as shown in FIG.
Although it is possible to output the signal of Si * K4 to output the second derivative signal, according to the fifth embodiment of the present invention shown in FIG. 27, the photoelectric conversion element 17 and the photoelectric conversion by the differential amplifier 32 are provided. The result of the differential output of the signal with the element 18 is
It can be the second derivative signal.

Therefore, in the fifth embodiment of the present invention, the optical axis A is controlled by the computer 20 and the actuator AT.
A half-wave plate HW rotatable about X is added.
The polarizing beam splitter 14e includes first, second, third, and fourth
Similarly to the embodiment, the polarization beam splitter 14 in which the analyzer angle is set so as to transmit the light having an angle of 45 degrees with respect to the incident light is further rotated by 45 degrees. In this case, the output of the differential amplifier 32 is
Only the second-order differential component described above is output.

[0138] Except for the conditions of the analyzer angle of the polarizing beam splitter 14e and the azimuth of the half-wave plate HW, the image is a mixture of the amplitude differential image and the intensity differential image. Further, the amplitude differential image and the intensity differential image are strengthened or weakened at an analyzer angle of the polarizing beam splitter 14e of 180 degrees. When the half-wave plate HW is rotated, the angle of the polarization beam splitter 14 becomes twice as large.
This is equivalent to rotating the analyzer angle of e.

When the analyzer angle of the polarizing beam splitter 14e and the azimuth angle of the half-wave plate HW are adjusted, the amplitude differential image and the intensity differential image weaken each other, and finally the intensity differential image and the intensity differential image become 2
It is possible to leave only the second derivative image. Note that another secondary differential signal is obtained from the difference between the signals obtained from the differential amplifier 57 and the differential amplifier 32.

By the way, in the defect detection apparatus according to the fifth embodiment of the present invention, a suitable signal processing circuit is shown in FIG.
FIG. Those given the same reference numerals in FIG. 28 as those in FIG. 27 are the same members. By the way, the photoelectric conversion elements 17, 18, 48, 49, 56, 59 are inputted to preamplifiers A provided in the differential amplifiers 32, 19, 57, respectively. The output of each of the photoelectric conversion elements 17, 18, 48, and 49 is amplified by the preamplifier A with an appropriate amplification gain. Next, the photoelectric conversion element 1
Outputs from 7 and 18 are input to a differential amplifier circuit D1 in the differential amplifier 32. Similarly, outputs from the photoelectric conversion elements 48 and 49 are sent to a differential amplifier circuit D2 in the differential amplifier 19,
The output of the photoelectric conversion elements 56 and 59 is
Is input to the differential amplifier circuit D3.

Here, the differential amplifier circuit D1 outputs a secondary differential signal from the signals from the photoelectric conversion elements 17 and 18. Further, the differential amplifier circuit D2 outputs an intensity differential signal in the reflected light from the reticle 8, and the differential amplifier D3 outputs an intensity differential signal in the transmitted light from the reticle 8. Next, the output signals of the differential amplifier circuits D2 and D3 are output to the signal processing circuit 24e.
Is input to a balance adjustment circuit Bal in
The peak values of the output signal from D3 are aligned. Then, a second derivative signal is output from the outputs from D2 and D3 in the waveform synthesis circuit Mix.

Next, the secondary differential signal obtained from the differential amplifier 32 and the waveform synthesizing circuit Mix in the signal processing section 24e.
Is adjusted by the differential amplification circuit D4 in the signal processing unit 24e after the relative intensity is adjusted. The output of the differential amplifier D4 becomes the aforementioned error signal Es. Next, this error signal Es is input to the window comparator Wcom in the detection circuit 33 to which two signals of positive and negative slice levels Th.H and Th.L are input. The error signal Es is binarized by the window comparator Wcom, and a Det signal indicating the presence or absence of a foreign substance is output.

As for the detection of the size of the foreign matter,
The outputs of the differential amplifier circuit D1 and the waveform synthesizing circuit Mix are used. These are signal selectors SS in the signal processor 24e.
Is selected by The signal selector SS may be, for example, a maximum value output circuit that selects and outputs a stronger signal strength, or may be a minimum value output circuit. This should be chosen according to the intended use.

By the way, the circuit configuration in FIG. 32 can be applied to the first embodiment of the present invention as it is, in which case the differential amplifier circuit D1 in the differential amplifier 32 and the waveform synthesizing circuit Mix are not used. It goes without saying that an amplitude differential signal (primary differential signal) is output. Further, as can be said in all the embodiments, the waveform synthesizing circuit has a function of either an adder or a differential amplifier (subtractor). Selection of addition or subtraction depends on the polarity of the output signal of the differential amplifiers D2 and D3. For example, if the peak value due to the edge has the opposite polarity, an adder is used. Further, the waveform synthesizing circuit is a differential amplifier, and the differential amplifying circuit D2 or D2
It goes without saying that the signal of the photoelectric conversion element input to 3 may be exchanged. [Sixth Embodiment of the Present Invention] Next, a defect detection apparatus according to a sixth embodiment of the present invention will be described. FIG. 33 shows the configuration of the defect detection apparatus according to the sixth embodiment of the present invention.
Shown in 33 that are the same as those in FIG. 1 are the same as those in the first embodiment of the present invention. By the way, the sixth embodiment of the present invention is different from the above-described embodiments of the present invention only in the optical system for capturing the reflection image and the detector. A major feature of the sixth embodiment of the present invention is that a second derivative similar waveform generation circuit Sd is added.

FIG. 34 is a system diagram of a signal processing circuit of this defect detection apparatus. Incidentally, the second derivative similar waveform generation circuit Sd includes an offset adjustment circuit Offset and a square circuit Square as shown in FIG.
The differential amplifier circuit D1 in the differential amplifier 32 and the differential amplifier 19
The differential amplifier circuit D2 outputs a reflected amplitude differential signal and a reflected intensity differential signal as in the first embodiment of the present invention. Therefore, the primary differential signal of the defect-free circuit pattern can be removed from these outputs. Therefore, it is clear that the image of the defect-free circuit pattern can be removed if the secondary differential similar waveform generation circuit Sd generates the secondary differential signal.

Therefore, the second derivative similar waveform generation circuit Sd will be described. FIG. 3 also shows a schematic diagram of the waveform.
This will be described with reference to 5, 36, 37, 34, 38 and 39. FIG. 35 shows a signal obtained when the photoelectric conversion element 17 receives light. With respect to this signal, the value of Offset1, which is the amount of offset to be applied, is determined as follows.
The offset amount Offset1 is set to be a median value with respect to the peak values of the edge portions 1 and 2 of the output signal of the photoelectric conversion element 17. Then, this offset amount Offset1 is applied to the output signal of the photoelectric conversion element 17 by an offset adjustment circuit. Next, the output signal of the photoelectric conversion element 17 to which the offset has been applied by the offset adjustment circuit is input to the squaring circuit. FIG. 36 shows the output from the squaring circuit square after such processing.

Similarly, the same processing is performed by the photoelectric conversion element 18 shown in FIG. The offset amount Offset2 is added to the signal output from the photoelectric conversion element 18 first.
Is set to be a median value with respect to the peak values of the edge portions 1 and 2. Next, the set offset amount is applied to the output signal from the photoelectric conversion element 18 by an offset adjustment circuit. Then, the output signal of the photoelectric conversion element 18 to which the offset amount Offset2 has been applied by the offset adjustment circuit is next input to the squaring circuit square. The output from the squaring circuit “square” that has undergone such processing is shown in FIG.

The output signal of the photoelectric conversion element 17 and the output signal of the photoelectric conversion element 18 output from the respective squaring circuits.
Is input to the differential amplifier. A schematic diagram of the waveform of the signal thus obtained is as shown in FIG. Thus, a signal having a waveform almost similar to the second derivative signal is obtained. However, the signal thus obtained is
Strictly speaking, it is not the same as the second derivative signal. Therefore, the degree of similarity was next evaluated by simulation.

FIG. 36 shows amplitude differential signals [270]-[9].
0] of FIG. Also, FIG. 7 shows a waveform 4002 of the signal [270] obtained by the photoelectric conversion element 18 and a waveform 4003 of the signal [90] obtained by the photoelectric conversion element 17 together. FIG. 41 shows the intensity differential signal Idif.
The waveform 4004 of f is shown. By the way, the intensity differential signal Id
“iff” is a signal output from the differential amplifier 19.
FIG. 41 also shows the output signal of the photoelectric conversion element 48.
A waveform 4005 of (−0.25) and a waveform 4006 of the output signal (0.25) from the photoelectric conversion element 49 are displayed.

By the way, the amplitude differential signal [270]-[90] is matched with the peak value of the intensity differential signal Idiff, and the secondary differential signal waveform 400 obtained by removing the primary differential component is obtained.
7 is shown in FIG. A waveform 4004a of the intensity differential signal Idiff combining the amplitude differential signals [270]-[90] and the peak value
And the waveform 4001 of the amplitude differential signal [270]-[90].

FIG. 43 shows how the offset adjusting circuit of the second derivative similar waveform generating circuit Sd adjusts the offset. In the adjustment methods shown in FIGS. 38 and 40, the waveform indicating the pattern edge is dull due to the effect of the objective lens, and cannot be applied as it is. Since the purpose of adjusting the offset amount lies in the elimination of the first derivative, the offset amount is adjusted so as to remove this. That is, the value of the second derivative similar waveform generated from the intermediate position between the pattern edge positions indicated by the light EO and the light OE is set to be zero. FIG. 43 shows the waveform 4003a of the output signal of the photoelectric conversion element 17 after the offset application and the waveform 4002a of the output signal of the photoelectric conversion element 18.

Therefore, in the sixth embodiment of the present invention,
The model used for the simulation is the reticle pattern shown in FIG. 26B, and a signal (R, [90] -DCport) obtained by applying an offset to the output signal from the photoelectric conversion element 17.
ion) and a signal (R, [270] -DCportion) obtained by offsetting the output signal from the photoelectric conversion element 18 are δ which is half of the sheer amount 2δ with respect to the position of the pattern edge.
The edge of the circuit pattern is shifted by +0.25 μm and −0.25 μm. So, if you adjust the offset,
Since the position intersecting with the horizontal axis (zero intensity level) of the graph changes, adjust the offset amount by the same amount for the two waveforms and (R, [90] -DC
portion) signal peak value and (R, [270] -DCportio
Set so that the absolute value and the peak value of the signal waveform of n) match. This setting is performed by the offset adjustment circuit offset of the secondary differential similar waveform generation circuit Sd.

After the Offset adjustment is performed as described above, the peak value of each signal is squared by the squaring circuit square. FIG. 44 shows a waveform as a result of squaring in this manner.
A signal obtained by applying an offset to the output signal from the photoelectric conversion element 17 and taking the square becomes a waveform 4008, and a signal obtained by applying an offset to the output signal from the photoelectric conversion element 18 and taking the square becomes a waveform 4009. Becomes Then, when the difference between these signals is calculated, a waveform 4010 in FIG. 44 is obtained.
This waveform 4010 is a second derivative similar waveform signal (90ac ^ 2-270
ac ^ 2). The two signals obtained from the respective squaring circuits are differentiated by a differential amplifier circuit D3 to obtain a second derivative similar waveform signal (90ac ^ 2-270ac ^ 2).

The second derivative similar waveform signal (90ac ^ 2-270ac ^ 2) obtained as described above and the signal processing unit 24 shown in FIG.
The secondary differential signal, which is an output signal from the differential amplifier D4 provided in the signal processing circuit 24,
Input and output sum signal. The secondary differential similar waveform signal output from the secondary differential similar waveform generation circuit Sd is:
The output signal of the differential amplifier D4 and the peak value can be made uniform by the amplifier Bal. The waveform of the signal thus obtained is shown in FIG. A waveform 4010a is an output signal from the second derivative similar waveform generation circuit and is an output signal from the amplifier Bal. A waveform 4011 is an output signal of the differential amplifier D5, and is a sum signal of a second derivative similar waveform signal of the waveform 4010a and a second derivative signal of the waveform 4007.

In this example, the second derivative similar waveform; (90ac
Since the phase of ^ 2-270ac ^ 2) is opposite to that of the second derivative waveform, the second derivative waveform was canceled by addition, but when creating a second derivative similar waveform; [(90ac ^ 2-270ac ^ 2)] [(270ac ^ 2-90ac ^ 2)] is 2 according to the subtraction direction of
It has the same phase as the next differential waveform. By the way, in FIG.
The above waveforms are shown together. In FIG. 46, the peak value is calculated for the waveform 4001 of the output signal ([270]-[90]) from the differential amplifier 32 and the output signal ([270]-[90]) from the differential amplifier 32. The output signal Idiff from the aligned differential amplifier 19
And a second differential intensity signal (2nd derivativ) which is an output signal of the differential amplifier D4 in the signal processing unit 24f.
e) waveform 4007 and second derivative similar waveform signal (90ac ^ 2-2
A waveform 4011 of [resi (90ac ^ 2-270ac ^ 2)], which is an error signal Es as a result of adding the 70ac ^ 2) and the second derivative signal (2nd derivative), is shown. In addition, the differential amplifier 19
And the second derivative similar waveform signal (90a
c ^ 2-270ac ^ 2)
12 is also shown. Thus, it can be seen that the error signal Es; resi (90ac ^ 2-270ac ^ 2) is sufficiently smaller than the primary differential signal and the secondary differential signal.

As described above, the second derivative similar waveform generating circuit Sd
If the sum or difference of the signals is further calculated by the differential amplifier circuit D5 from the signal of the amplitude differential intensity and the intensity differential signal, the signal of the edge of the chrome pattern can be suppressed to a low signal. At this time, the signal from the second derivative similar waveform generation circuit Sd, and the signal of the amplitude differential intensity and the intensity by the intensity differential are input to the differential amplifier circuit D5 with their peak values almost aligned by the balance circuit Bal. doing.

FIG. 48 is an enlarged view of FIG. Although such a small signal, the error signal Es outputs a signal about the pattern edge. FIG. 48 shows an error signal Es; resi (9) when the line width of the glass portion is changed to 5 μm, 3 μm, and 1 μm in the circuit pattern model.
0ac ^ 2-270ac ^ 2). As can be seen from this figure, the relative ratio and offset amount of the peak value in the process of calculating the error signal are
Standardized at 5 μm. Therefore, it can be seen that the error signal hardly depends on the dimensions of the circuit pattern.
This is very important for this type of testing equipment,
If calibration is performed once in an arbitrary pattern portion on the reticle using the same light shielding member, only a uniform and sufficiently small error signal is generated in any circuit design. Therefore, if an appropriate fixed threshold value is set for the error signal, this defect detection device can easily detect only the defect on the reticle. [Seventh Embodiment of the Present Invention] Next, a defect detection apparatus according to a seventh embodiment of the present invention will be described. The overall configuration diagram of the defect detection apparatus according to the seventh embodiment of the present invention is exactly the same except for the second derivative similar waveform generation circuit. Only differences from the defect detection apparatus according to the sixth embodiment of the present invention will be described.

Incidentally, the defect detecting apparatus according to the seventh embodiment of the present invention uses a second derivative similar waveform generator circuit using a second derivative similar waveform generator circuit Sd2 as shown in FIG. This second derivative similar waveform circuit Sd2 is the same as the second derivative similar waveform generator Sd used in the sixth embodiment.
Instead of the square circuit square, an absolute value circuit abs is used. Then, the absolute value of the output signal from the offset adjustment circuit offset is output by the absolute value circuit abs. As described above, in the second derivative similar waveform generating circuit of the seventh embodiment of the present invention, the offset from the outputs from the photoelectric conversion elements 17 and 18 is determined in the same manner as in the sixth embodiment of the present invention. The absolute value is calculated based on the offset.

Note that the other steps are the same as those of the defect detection apparatus according to the sixth embodiment of the present invention, and the description is omitted. By the way, the offset adjustment is ended by the offset adjustment circuit offset of the second derivative similar waveform generation circuit Sd2,
And the absolute value signal ABS [270ac] output by the absolute value circuit abs
Waveform 5001 and the absolute value signal ABS [90ac] waveform 5002
The waveform of FIG. In FIG. 50, FIG.
This is a result of simulation assuming the model of (b).

Then, the absolute value signal ABS [270ac] and the absolute value signal ABS [90ac] are respectively converted into a second derivative similar waveform generating circuit S.
The signal is input to the differential amplifier D3 in d2 to generate a second derivative similar waveform signal diff. | 270ac |-| 90ac |. FIG. 50 also shows the waveform 5003 of the second derivative similar waveform signal diff. | 270ac |-| 90ac |. After adjusting the relative strength between the second derivative signal and the second derivative similar waveform signal diff. | 270ac |-| 90ac | output from the differential amplifier D4, the second derivative signal and the second derivative similar waveform signal To the differential amplifier 24f in the signal processing unit 24f, an error signal Es [resi, Idiff, | 270ac |-| 90ac |] can be output. FIG. 51 shows an error signal Es; [resi,
Idiff, | 270ac |-| 90ac |]. This figure shows that the chrome pattern interval dimension is 1 μm, 3 μm, 5 μm
The error signal Es in the case of is shown. As described above, also in the defect detection device according to the seventh embodiment of the present invention, the edge signal due to the chrome pattern could be reduced. [Eighth Embodiment of the Present Invention] Next, a defect detection apparatus according to an eighth embodiment of the present invention will be described. FIG. 52 shows the configuration of the defect detection apparatus according to the eighth embodiment of the present invention.

The difference from the defect detection apparatus according to the sixth embodiment of the present invention is that the photoelectric conversion elements 48 and 49 are different.
Is to output a second derivative similar waveform signal by the second derivative similar waveform generation circuit Sdh on the basis of the output signal of the above. Note that the configuration of the same reference numerals as in FIG. 33 is the same as that of the defect detection apparatus according to the sixth embodiment of the present invention, and the description is omitted here. FIG. 53 shows a system diagram of signal processing in the defect detection device according to the eighth embodiment of the present invention. As described above, in the defect detection apparatus according to the eighth embodiment, signals from the photoelectric conversion element 48 and the photoelectric conversion element 49 are input to the second derivative similar waveform generation circuit Sdh. Then, the signals of the photoelectric conversion elements 48 and 49 input to the second derivative similar waveform generation circuit Sdh are input to the offset adjustment circuit offset. The signals output from the offset adjustment circuit offset are input to the absolute value circuits abs. The waveform of the output signal from the absolute value circuit abs obtained by such a method is shown in FIG. FIG. 54 shows an absolute value circuit ab obtained based on the signal output from the photoelectric conversion element 48.
s output signal abs [I-ac] waveform 5401 and an absolute value circuit ab obtained based on the signal output from the photoelectric conversion element 49
In addition to the waveform 5402 of the output signal abs [I + ac] of S, the output signal abs [I + ac] -abs [I-ac] from the differential amplifier D3 in the second derivative similar waveform generation circuit Sdh. A waveform 5403 is shown. In this way, by inputting the two signals output from the absolute value circuit abs to the differential amplifier D3,
A second derivative similar signal; abs [I + ac] -abs [I-ac] was formed.

And a second derivative similar waveform signal; abs [I + a
The relative intensity between c] -abs [I-ac] and the second derivative signal, which is the output signal from the differential amplifier D4 of the signal processing unit 24f, is represented by an amplifier B.
By adjusting with al and inputting it to the differential amplifier D5 in the signal processing unit 24f, an error signal Es; resi, iac diff can be output. The differential output unit D1 in FIG.
The differential amplifier 19 is provided in the differential amplifier 19, and the differential output unit D 2 is provided in the differential amplifier 32.

FIG. 55 shows an error signal Es; res
The signal waveform of i, iac diff is shown. FIG. 55 also shows the pattern edge widths of 1 μm and 3 μm. Thus, it can be confirmed that even when the pattern dimension changes, the maximum peak value does not change. Thus, it was confirmed that the signal processing method does not need to change the slice level according to the pattern width.

As an application of the eighth embodiment of the present invention, the following configuration may be used. FIG. 56 shows a system diagram of signal processing of this application example. The difference from the previous embodiment is that a square circuit square is used instead of the absolute value circuit abs in the second derivative similar waveform generation circuit. Two lights O shifted by the shear amount
E, FIG. 57 shows how a second derivative similar waveform signal is formed from two signals representing the intensity image of light EO. In this application example, in the same manner as in the sixth embodiment of the present invention,
The signal outputs of the photoelectric conversion elements 48 and 49 are adjusted by an offset adjustment circuit Offset, and these signals are squared and input to the differential amplifier D3 to obtain a second derivative similar waveform signal; [Iac] ^ 2,
diff can be formed. FIG. 57 shows the waveform 5701 of the output signal [I-ac] ^ 2 from the photoelectric conversion element 48 that has passed through the offset adjustment circuit offset and the square circuit square, and the waveform of the photoelectric signal that has passed through the offset adjustment circuit offset and the square circuit square. A waveform 5702 of the output signal [I + ac] ^ 2 from the conversion element 49,
A second derivative similar waveform signal; a waveform 5703 of [Iac] ^ 2, diff.

To obtain the error signal Es in this application example, the secondary differential signal and the secondary differential analog signal which are the output signals from the differential amplifier D4 in the signal processing unit 24f; [Iac] ^ 2, d
It can be obtained by adjusting the relative intensity with respect to iff and inputting it to the differential amplifier D5 in the signal processing unit 24f. The waveform 5704 of the error signal Es; resi, iac-2, diff is shown in FIG.

FIG. 58 additionally shows the signal processing section 24f.
Differential signal 2nd de which is the output signal of the differential amplifier D4 of FIG.
rivative and three error signals resi, Idiff, | 270ac |-| 90ac |, 5 μm and resi,
iac diff, 5μm and resi, iac ^ 2, diff, 5μm. Each error signal Es is larger than the waveform 4011 shown in FIG.

Thus, it can be understood that the second derivative similar waveform signal which is least affected by the pattern edge is the defect detection device according to the sixth embodiment of the present invention. In addition,
It goes without saying that the concept of the present invention can also be used by using a second derivative similar waveform signal generated in another form. [Ninth Embodiment of the Present Invention] FIG. 59 is a block diagram of a defect detection apparatus according to a ninth embodiment of the present invention. In the ninth embodiment of the present invention, a half-wave plate HW rotatable via an actuator AT controlled by a computer 20 is provided. With such a configuration, the differential amplifier 32 can output a second-order differential signal as in the above-described fourth embodiment of the present invention.

The ６８ wavelength plate Q along the optical axis AX2
Since W is added, the photoelectric conversion elements 48 and 49 output an interference image signal having a phase difference of (1/2) π and an interference image signal having a phase difference of-(1/2) π. By the way, FIG. 60 shows a system diagram of a signal processing system of the defect detection device according to the ninth embodiment of the present invention. In this defect detection device, the output signals of the photoelectric conversion elements 48 and 49 are sent to the second derivative similar waveform generator Sdi, which is equivalent to the second derivative similar waveform generator of the sixth embodiment of the present invention described above. Input, 2
It is converted to a second derivative similar waveform signal.

The peak values of the output signal from the differential amplifier 32 and the output signal from the second derivative similar waveform generation circuit Sdi are set by the respective amplifiers Bal so that the error signal Es is minimized. Each of the output signals for which the peak value is set is input to the differential amplifier D5 in the signal processing unit 24g, and outputs an error signal Es.
As described above, in the ninth embodiment of the present invention, the secondary differential signal is output by the differential output circuit D2 in one differential amplifier 32 due to the effect of the rotatable half-wave plate. The second derivative similar waveform generation circuit Sd can generate a second derivative similar waveform by the same operation as that of the sixth embodiment of the present invention. The differential amplifier D5 in the signal processing unit 24g outputs the error signal Es to the window comparator Wcom in the detection circuit 33. The window comparator Wcom binarizes the binarized signal and indicates the detection of a foreign object as a Det signal.

By the way, the Pout described in FIG.
The signal is a signal representing the size of the defect, and is selected by the signal selector Ss from the outputs of the differential amplifier circuits D2 and D5. The signal selector SS may be, for example, a maximum value output circuit that selects and outputs a strong signal strength, or may be a minimum value output circuit. This should be chosen according to the intended use. However, the differential amplifier circuit D5
Is best suited for this purpose because it is not affected by circuit patterns.

Note that the window comparator Wcom and the signal selector Ss described here are not limited to this embodiment, but can be applied to all embodiments. [Tenth Embodiment of the Present Invention] FIG.
0 is a defect detection device according to the embodiment. In the defect detection devices according to the above-described embodiments, the amplitude differential signal is always required, but in the tenth embodiment of the present invention, this is not required. In the tenth embodiment of the present invention, all of the photoelectric conversion elements 48, 49, 56, 59 output bright field image signals.

Accordingly, the photoelectric conversion elements 48 and 49 output bright-field images of the light reflected by the reticle 8, which are shifted from each other by 0.5 μm of the shear amount 2δ by 0.5 μm on the scale of the reticle. ing. The photoelectric conversion elements 56 and 59 output signals of two transmitted bright-field images which are bright-field images of light transmitted through the reticle 8 and are laterally shifted by the same scale as the two reflected bright-field images on the reticle.

Note that there is no problem even if the Nomarski prism 6 is not provided. This is because there is no need to create an interference image. The waveform shown in FIG. 62 is the waveform of the output signals of the photoelectric conversion elements 56 and 59 that have received two transmitted bright-field images having a shear amount 2δ of 0.5 μm apart, and further adjusts these output signals by offset adjustment. This is a waveform when an offset is applied by the circuit Offset. Waveform 6201
Is the waveform of the output signal from the photoelectric conversion element 56 to which the offset is applied, and the waveform 6202 is the waveform of the output signal from the photoelectric conversion element 59 to which the offset is applied. The offset amount of the offset adjustment circuit is adjusted in the same manner as in the sixth embodiment of the present invention.

The output signals from the photoelectric conversion elements 56 and 59 to which the offset has been applied as described above are input to squaring circuits, respectively, and when each of them is squared, a signal waveform shown in FIG. 62 is obtained. Incidentally, a waveform 6301 is an output signal from the photoelectric change element 56 that has passed through the offset adjustment circuit and the squaring circuit, and a waveform 6302 is an output signal from the photoelectric change element 59 that has passed through the offset adjustment circuit and the squaring circuit.

The output signal from the photoelectric change element 56 that has passed through the offset adjustment circuit and the squaring circuit and the output signal from the photoelectric change element 59 that has passed through the offset adjustment circuit and the squaring circuit are each subjected to a second derivative similar waveform generation. By inputting to the differential amplifier D3 of the circuit Sdj, it is possible to obtain a second derivative similar waveform signal; [Itac] ^ 2, diff in the transmission image. In addition, the second derivative similar waveform signal in the transmission image; [Ita
The waveform 6303 of c] ^ 2, diff is shown in FIG. FIG.
As can be seen from the graph, the waveform has a zero cross point at the pattern edge position (+2.5 μm, −2.5 μm position) before shearing.

By the way, the second derivative similar waveform signal based on the reflected image of the reticle 8 is generated as follows. The waveform shown in FIG. 64 is the waveform of the output signals of the photoelectric conversion elements 48 and 49 that have received two reflected bright-field images whose shear amount 2δ is 0.5 μm apart. Is a waveform when an offset is applied. A waveform 6401 is a waveform of an output signal from the photoelectric conversion element 48 to which the offset has been applied.
02 denotes a waveform of an output signal from the photoelectric conversion element 49 to which an offset has been applied.

The output signals from the photoelectric conversion elements 48 and 49 to which the offset has been applied as described above are input to squaring circuits, and when each of them is squared, a signal waveform shown in FIG. 65 is obtained. Incidentally, a waveform 6501 is an output signal from the photoelectric change element 48 that has passed through the offset adjustment circuit and the squaring circuit, and a waveform 6502 is an output signal from the photoelectric change element 49 that has passed through the offset adjustment circuit and the squaring circuit.

The output signal from the photoelectric conversion element 48 that has passed through the offset adjustment circuit and the squaring circuit and the output signal from the photoelectric conversion element 49 that has passed through the offset adjustment circuit and the squaring circuit are each subjected to a second derivative similar waveform generation. By inputting the signal to the differential amplifier D4 of the circuit Sdj, it is possible to obtain a second derivative similar waveform signal in the reflected image; [Iac] ^ 2, diff. In addition, the second derivative similar waveform signal in the reflected image; [Ia
The waveform 6503 of c] ^ 2, diff is shown in FIG. Fig. 65
As can be seen from the graph, the waveform has a zero cross point at the pattern edge position (+2.5 μm, −2.5 μm position) before shearing.

Next, a second derivative similar waveform signal [Iac] ^ 2, diff in the reflected image of the reticle 8 and a second derivative similar waveform signal [Itac] ^ 2, diff in the transmitted image of the reticle 8 are synthesized. Then, a combined second derivative waveform [Iac] ^ 2, diff, ave is generated. By the way, the synthesized second derivative waveform [Iac] ^ 2, diff, ave is a second derivative similar waveform of reflection at a ratio such that the peak values at the rise and fall are equal; [Iac] ^ 2, diff and the transmission Second derivative similar waveform; [Itac] ^ 2, the polarities of diff are matched and then added.

FIG. 83 shows a second derivative similar waveform signal in the reflected image of the reticle 8; [Iac] ^ 2, diff and a second derivative similar waveform in the transmitted image of the reticle 8; [Itac] ^ 2, diff
[Iac] ^ 2, d
A waveform 8301 of iff and ave is shown. FIG. 83 also shows the waveforms of the output signals [I-ac] ^ 2 and [I + ac] ^ 2 from the photoelectric conversion elements 48 and 49 via the offset adjustment circuit and the squaring circuit.

By the way, FIG. 62 is obtained by amplifying the intensity differentiated signals based on the intensity differential images of the transmission and reflection from the reticle 8 with desired gains, and adding the respective signals to obtain (Si * K4 + Sit *). Second derivative signal 2nd obtained from K5)
derivative waveform 6601 and the second derivative signal 2nd de
The peak value of the synthetic second derivative waveform [Iac] ^ 2, diff, ave so that the result of subtracting the polarity of the combined second derivative waveform [Iac] ^ 2, diff, from the rivative is minimized A signal 6602 of an error signal resi, iac ^ 2, diff, ave, and 5 μm, which outputs a difference from the second derivative signal 2nd derivative, is shown using the signal adjusted for. The second derivative signal 2nd derivati
ve is the second derivative signal shown in the sixth embodiment of the present invention.
Same as 2nd derivative.

FIG. 67 shows a model of a circuit pattern as shown in FIG.
When the line width of the glass portion is changed to μm, 3 μm, and 1 μm, the error signal Es according to the tenth embodiment of the present invention;
The signal waveform when resi (90ac ^ 2-270ac ^ 2) is output is shown. Relative ratio of peak value and Offset in the process of calculating error signal
Are standardized at 5 μm. As can be seen from this figure, the error signal hardly depends on the dimensions of the circuit pattern.

FIG. 68 shows a signal processing circuit system diagram suitable for the tenth embodiment of the present invention. In the figure, the output signals of the photoelectric conversion elements 48 and 49 are
And the photoelectric conversion element 56,
The output signal of 59 is a differential output circuit D2 in the differential amplifier 57.
Is output to Further, in the tenth embodiment of the present invention, the output signals of the photoelectric conversion elements 56 and 59 are also output to the second derivative similar waveform generation circuit 1, and similarly, the photoelectric conversion element 4
The output signals 8 and 49 are input to the second derivative similar waveform generation circuit 2. Then, the differential output circuit D1 outputs a reflection intensity differential signal, and the differential output circuit D2 outputs a transmission intensity differential signal. Each output signal of the differential output circuit D1 and the differential output circuit D2 is adjusted in relative intensity by the balance circuit Bal, and is converted into a secondary differential signal by the differential amplifier circuit D4.

At the same time, the two second-order differential similar waveform generating circuits 1 and 2 output two second-order differential similar waveform signals by the method described above, and these signals are used as the waveform synthesizing circuit Mi.
At x, the signal is converted into a synthesized secondary differential waveform signal by the method described above. Then, the combined secondary differential waveform signal and the differential amplifier D
The normal secondary differential signal, which is the output signal of No. 4, is input to the differential output circuit D5 in the signal processing unit 24h and is converted into an error signal Es.

The error signal Es is input by the window comparator Wcom. It is binarized by the window comparator Wcom with two threshold values, which are output as a Det signal. Adder A
In dd, it is possible to add the signal for the transmitted bright-field image and the signal for the reflected bright-field image, delete the image other than the edge of the circuit pattern, and leave only the edge image of the foreign matter and the circuit pattern. Therefore, although it is difficult to detect a foreign substance using the output of the adder Add due to the influence of the edge image, it is possible to measure the signal intensity of the defect. An arbitrary signal is selected or added by the signal selector SS from the addition signal of the adder Add and the error signal Es which is the output signal of the differential output circuit D5 in the signal processing unit 24g, and is output. Since the signal selector SS also has a function of outputting the minimum signal and the maximum signal, it is optional to determine which signal determines the size of the defect, and the operator can select the defect.

Further, the phase modulation amount (φ) representing the height of a defect or a foreign substance can be measured from Expression (14) or the like, and this can be included in the inspection result. This is applicable to the defect detection devices of all the embodiments of the present invention. In addition, the first of the present invention
In the zeroth embodiment, the square operation for forming the secondary differential signal and the composite secondary differential signal may be an arithmetic operation for obtaining an absolute value, which is referred to as an eleventh embodiment of the present invention. And A suitable signal processing circuit may be obtained by changing the square circuit Square shown in FIG. 68 to the above-described absolute value circuit abs.

Next, a description will be given of a defect detection apparatus thus modified as a defect detection apparatus according to an eleventh embodiment of the present invention. [Eleventh Embodiment of the Present Invention] In describing the eleventh embodiment of the present invention, a simulation waveform will be used.

FIG. 69 shows a case where an offset adjustment circuit Offset is added to the output signals of the photoelectric conversion elements 56 and 59, which are the intensity images of the light transmitted through the reticle 8, and the output from the offset adjustment circuit is input to the absolute value circuit abs. 5 shows a waveform of a signal obtained by the above method. The waveform 6901 of the signal abs [It-ac] obtained by the photoelectric conversion element 56 and the photoelectric conversion element 59
Shows a waveform 6902 of the signal abs [It + ac] obtained by the above. Next, the signal output from the absolute value circuit abs is
By inputting to the differential output circuit D3 in the second derivative similar waveform generation circuit 1, the second derivative similar waveform signal abs [It + ac] -abs
[It-ac] is obtained. This second derivative similar waveform signal abs [I + a
The waveform 6903 of c] -abs [I-ac] is also shown in FIG. By the way, as described above, the offset amount applied by the offset adjustment circuit Offset is a second derivative similar waveform; abs [It + ac]
-abs [It-ac] is set so that the zero cross point is at the pattern edge position before shearing.

Next, a reflected image from the reticle 8 will be described. FIG. 70 is obtained by adding an offset adjustment circuit Offset to the output signals of the photoelectric conversion elements 48 and 49, which are the intensity images of the light reflected by the reticle 8, and inputting the output from the offset adjustment circuit to the absolute value circuit abs. 4 shows a signal waveform. Note that the signal obtained by the photoelectric conversion element 58
A waveform 7001 of abs [I-ac] and a waveform 7002 of a signal abs [I + ac] obtained by the photoelectric conversion element 49 are shown. Next, the signal output from the absolute value circuit abs is input to the differential output circuit D4 in the second derivative similar waveform generation circuit 2, whereby the second derivative similar waveform signal abs [I + ac] -abs [Ia
c] is obtained. This second derivative similar waveform signal abs [I + ac] -ab
A waveform 7003 of s [I-ac] is also shown in FIG.

As described above, the offset amount applied by the offset adjustment circuit Offset is the pattern edge before the zero cross point of the second derivative similar waveform signal; abs [I + ac] -abs [I-ac] is sheared. Set to come in position. And then a second derivative similar waveform signal based on the transmitted image;
abs [It + ac] -abs [It-ac] and a second derivative similar waveform signal by an incident image; abs [I + ac] -abs [I-ac] are input to the combining circuit Mix shown in FIG. By doing so, a synthesized second derivative similar waveform signal: abs [Iac], diff, Ave is obtained.

FIG. 84 shows a second derivative similar waveform signal abs [It + ac] -abs [It-ac] in the transmission image of the reticle 8, and a second derivative similar waveform signal ab in the incident image of the reticle 8.
A composite secondary differential waveform: abs [Iac], which is a composite signal of s [I + ac] -abs [I-ac], and a waveform 8401 of diff, Ave are shown. By the way, this composite secondary differential waveform signal has a peak value of rising and falling, and a secondary differential similar waveform with an incident light: abs [I + ac]-
abs [I-ac] and transmission second derivative similar waveform: abs [It + ac] -abs
This is the result of adding the polarity after matching the polarity with [tI-ac].

The second derivative signal 2nd derivative obtained from the intensity differential image (Si * K4 + Sit * K5) of the light transmitted through the reticle 8 and the reflected light is a composite second derivative similar waveform signal: abs The combined second derivative similar waveform signal in which the peak value is adjusted so that the result of subtraction after the phases of [Iac], diff, and Ave are minimized, and the second derivative signal 2nd derivative are combined in the signal processing unit 24h. An error signal Es: resi, abs [iac], diff, ave is obtained from the differential output circuit D5. In addition,
In FIG. 71, the error signal Es: resi, abs [iac], diff, ave,
The waveform 7101 of 5 μm is shown. Furthermore, the second derivative signal 2n
The waveform 7102 of the d derivative is also shown.

FIG. 72 shows the model of the circuit pattern as 5
Error signal Es when the line width of the glass portion is changed to μm, 3 μm, 1 μm; resi, abs [iac], diff, ave, 5 μm, 3 μm,
Indicates 1 μm. The relative ratio of the peak values in the process of calculating the error signal and the value of the offset amount given by the offset adjustment circuit Offset are standardized at 5 μm. It can be seen from FIG. 72 that the error signal hardly depends on the size of the circuit pattern. [Twelfth Embodiment of the Present Invention] FIG.
The schematic configuration of the defect detection device according to the second embodiment is designated. The operating principle is basically the same as that of the tenth embodiment. Simulation waveforms obtained by this configuration can be shown in FIGS. 62 to 66.

In this defect detection apparatus, a Nomarski prism, a polarizing beam splitter, and the like are omitted, and the configuration in which laser light is optically scanned on the reticle 8 is the same as that of the first to eleventh embodiments. However, the lens 10, the lens 47, the mirror 65, and the photoelectric conversion element 49
, A bright field light receiving system, a lens 42, a lens 58,
Only a transmitted bright field light receiving system using the mirror 64 and the photoelectric conversion element 59 is used. In order to perform the same operation as in the tenth embodiment, it is necessary to use a laterally shifted transmission / reflection bright-field image or an intensity differential image of transmission / reflection, that is, an image indicating the difference in the intensity of the laterally shifted bright-field image. . Therefore, the signal processing system in this embodiment has a configuration as shown in FIG.

As shown in FIG. 74, the twelfth embodiment of the present invention
An intensity image is electrically differentiated from output signals from the photoelectric conversion elements 49 and 59 according to the embodiment to form an intensity differential signal. Specifically, in the present embodiment, since the image is a laser scanning optical system, the image signal is a time-series signal. This is branched into two, a time delay is given to one side, and the difference between the two is taken to obtain a differential value.

By the way, in FIG. 74, DL1 and DL2
Is a time delay element and analog elements such as a CCD and a glass delay line are used. According to a well-known digital technology, an arbitrary time delay waveform can be formed by using a rewritable memory. A major feature of this embodiment is that no Nomarski prism is used in the optical system. Therefore, there is no need to control the polarization of the optical path in the middle, and high-speed optical scanning can be performed, but the polarization characteristics are not very suitable for the optical system of the polarization interference.
rector) can be used.

In the embodiment of the present invention, the second derivative similar waveform generating circuits 1 and 2 are included in the signal processing section 24i. In any of the above embodiments, it is needless to say that the step (or the phase difference of the transmitted light) of the circuit pattern can be measured by using the equation (14). For example, according to the defect detection device of the present invention, the reticle with the phase shifter can be measured. The phase shift amount can be measured at the same time.

The inventor has found a new application field of the present invention from many simulation waveforms of the present invention. In the present specification, the amplitude differential signal is represented by Expression 5, and 1
It must be a second derivative waveform and do not include the components of the second derivative waveform. Further, it has been repeatedly pointed out that the intensity differential signal includes the first differential waveform and the second differential waveform represented by Expressions 8 and 10.
Further, in the present invention, the secondary differential signal is mixed with the primary differential signal in the intensity differential signal of transmission and reflection other than the amplitude differential signal, and the secondary differential signal is completely or almost completely converted from the intensity differential signal. It is also pointed out that a new first-order differential signal can be generated. After confirming this background,
The new application fields are described below.

The present inventors have found that the primary differential signal is a circuit pattern or an edge portion (step portion) of an object having a similar shape.
However, the waveform is always symmetrical with respect to the direction sheared by the Nomarski prism without depending on the height of the step and the difference in reflectivity, and the generation position is exactly the amount of shear I found that it was the center of two edges that were just separated. This property is very suitable for measuring the position of the edge of the circuit pattern. That is, the center position of the left-right symmetric primary differential waveform is determined, for example, by using FIG.
The primary differential waveform may be sliced at the level of the threshold value, and the median value may be obtained. When the circuit pattern is an object such as a photomask that can use transmitted illumination, as the primary differential waveform, a primary differential signal generated from an intensity differential image of transmission and reflection can be used in addition to an amplitude differential signal. The position of the pattern edge can be measured with an appropriate one of these primary differential images.

However, as shown in Equation 5, when the amplitude differential signal has no step, the signal becomes zero and the edge position cannot be measured. In such a case, it is desirable to use the primary differential signal from another method without using the amplitude differential signal. For example, there is a method of removing a secondary differential signal component from an intensity differential signal by a difference. When the circuit pattern to be detected is on a wafer that does not transmit light, there are many examples of using an amplitude differential signal as a primary differential waveform or outputting a primary differential signal from an intensity differential signal.
The edge position can be measured using a signal having a waveform almost coincident with the next differential waveform.

As a device for accurately measuring the edge position of a circuit pattern, a coordinate measuring device for a photomask and the accuracy of superposition exposure of a stepper are obtained by measuring the edge of a resist image on a developed wafer. There is an exposure one time before when a registration measuring device or a stepper performs overlay exposure, and a position measurement of an alignment mark formed at the time of development. In such an application, the pattern to be measured starts with a very low step (低 い 10n).
m) There is a step of about several microns. Therefore, the versatility is further improved if the optimal method of generating the primary differential signal can be selected according to the alignment mark.

In this case, it is desirable to obtain a first-order differential signal having a higher peak value because electrical and optical noise tolerance increases. When the bright field image of the edge changes depending on the polarization direction of the illuminating light, such as a resist image, the primary differential signal uses a method that does not use a Nomarski prism, a reflection intensity differential and a secondary differential similar waveform. By removing the second derivative similar signal from the intensity derivative signal, the first derivative similar signal is output. Then, it is desirable to measure the edge position of the object based on the first derivative similarity signal.

FIG. 76 shows a registration measuring device. The coordinate measuring unit can select the optimal first derivative signal or first derivative similar signal. Of these signals,
The optimum primary differential signal is selected from the optimum signal by the signal selection unit in the figure, and the coordinates are measured by the coordinate calculation unit from the waveform of the signal. FIG. 77 shows an alignment system for a stepper. The coordinate measuring unit can select the optimal first derivative signal or first derivative similar signal. Either the obtained first derivative signal or first derivative similar signal is selected. Then, the coordinate calculation unit indicates the coordinate measurement position from the selected signal. The interferometer measures the position of the stage and aligns the true position from these two measured positions.

The above-described apparatus measures the edge position by epi-illumination. In addition, application to a reticle appearance inspection apparatus for measuring or inspecting errors in a design value for manufacturing a reticle and a size, shape, position, and the like of a circuit pattern of the completed reticle can be considered. In this type of apparatus, a bright-field transmitted image is generally taken into a signal processing circuit by an objective lens, and is compared with design data. At this time, the edge of the circuit pattern is dull due to the objective lens as seen in many bright field images in this specification. Therefore, the position of the edge becomes unclear. In order to reduce the dullness of the image due to this lens, for example, since the influence of the PSF in Expression 11 is dull, it is conceivable to perform deconvolution by a well-known digital image processing technique using a spatial filter having an inverse characteristic. Such a technique would add a lot of high frequency noise to the image and would not reproduce ideal edge positions.

In this type of apparatus, the information necessary for the appearance inspection is the position of the edge of the circuit pattern, so that precise measurement of the pattern shape can be performed by using the primary differential signal. Further, since the circuit pattern is a two-dimensional object, it is possible to more completely grasp the edge position on the reticle by measuring the distribution of the primary differential signal in two directions in the plane where the circuit pattern exists. The appearance inspection can be easily performed by directly comparing the distribution of the edge positions with the design data (design value).

It is needless to say that a defect of the phase difference of the phase shifter portion of the reticle with the phase shifter can be inspected by using the equation (14). When an amplitude differential image is used as the primary differential waveform, there is a special effect that the edge positions of both the shifter portion and the chrome pattern portion can be accurately measured regardless of the presence or absence of the shifter. To generate the first derivative signal in two directions on the object plane, the first
According to the second embodiment, it is the simplest to configure the device by an optical system as shown in FIG. 73, and one-way operation in two directions can be performed in a short time by an electrical operation based on digital technology and analog technology. The distribution of the next derivative signal can be measured.
With such a waveform, simple signal processing can be converted into a distribution of edge positions.

FIGS. 78 and 79 show a reticle coordinate measuring instrument. The measuring instrument shown in FIG. 78 has only an incident light (reflection) optical system, and the measuring instrument shown in FIG. And The measuring device shown in FIG.
The system includes a system for obtaining a primary differential signal and a system for obtaining a primary differential analogous signal, and an optimal signal is selected by a signal selection unit. As one example of obtaining the first derivative similar signal, the signal delay means used in the twelfth embodiment of the present invention is used to electrically obtain the intensity differential signal, and further obtain the second derivative signal similar waveform. With the provision of the generation circuit, a first derivative similar waveform signal can be obtained.

FIG. 80 shows a reticle appearance inspection apparatus. This embodiment has an optical system for transmission and reflection. The reticle coordinate measuring device shown in FIG. 79 and the reticle appearance inspection device shown in FIG. 80 use the signals obtained from the transmission image and the incident light image to output the above-described first derivative signal or the first derivative similar waveform. Getting the signal output. The above-described application to the measurement of the pattern edge position can be achieved by applying a second derivative signal or a second derivative similar signal instead of the first derivative signal or the first derivative similar signal to the characteristic of the waveform (such as a circuit pattern or a similar signal). It takes a value other than zero at the edge part (step part) of an object of similar shape, but its waveform is always symmetrical in the differentiation direction regardless of the height of the step or the difference in reflectance, and its occurrence position is It is clear that the two edges are exactly the same apart by exactly the shear amount.) The secondary differential signal is a waveform having a mountain shape with one positive and one negative at one edge. It is apparent from FIG. 41 that the zero cross point at the center of this waveform coincides with the edge position. good. [Thirteenth Embodiment of the Present Invention] The inventor has found that there is a simpler method for the above edge position measurement when both transmitted light and reflected light are available. This will be described with reference to FIG. For example, when the measurement target is a reticle, the wavefront of the reflected light is shown in the figure, and the wavefront of the transmitted light is shown in the figure. The bright field image at this time is expressed by Expressions (6) and (7), and becomes like the reflected bright field image 1 and the transmitted bright field image in FIG. In these bright-field images, the effect of the objective lens is expressed in the same manner as Expressions (6) and (7) as PSF (point image intensity distribution is convolved and waveform edges become dull). When the three terms in parentheses on the right side of Expressions (6) and (7) are disassembled and shown in the figure, they become a reflected bright field image 2 and a transmitted bright field image 2, and the first term corresponds to The second term corresponds to, and the third term corresponds to. Therefore, the overshoot portion of the waveform corresponds to the edge position. Therefore, as shown in FIG. 81, an edge image can be obtained by adjusting and adding the relative intensities of the reflected bright-field image 1 and the transmitted bright-field image 1, adjusting the offset, and applying the signal to the added signal. This edge image is affected by the objective lens (PSF, point image intensity distribution is convolved) and becomes dull, but the inflection point always coincides with the edge position. FIG. 82 shows how edge positions are measured at intervals of 5 μm obtained by the above method. This corresponds to FIG. 75, and the edge position was found without any problem. It goes without saying that the present invention can be applied to a reticle coordinate measuring device and a reticle appearance inspection device.

The reticle coordinate measuring device and the reticle appearance inspection device based on the bright-field images of the transmitted light and the reflected light can reliably detect the edge position of the circuit pattern by a simple optical system, and can be used to design data and edge data. Position comparison is possible. For this reason, an inspection and measurement device excellent in cost performance can be configured. Such an apparatus corresponds to, for example, the apparatus shown in FIGS. 79 and 80 having the optical system shown in FIG.

It is apparent that the above-described embodiment can be used in combination with ordinary illumination other than the laser scanning technique, for example, illumination of a mercury lamp or a halogen lamp, and an image pickup device.

[0211]

As described above, according to the present invention, a conventional reticle having a pattern formed by a light-shielding film and a phase shifter portion having a halftone reticle formed by using only a phase shifter formed of a light-transmitting thin film can be used. It is possible to provide a detection device capable of performing an inspection such as an abnormality of a phase shift amount and the presence / absence of foreign matter on a light-transmitting phase object.

Further, since the edge position of the pattern can be measured accurately, it can be used for various position measurements and visual inspection of the complementary and mask. Further, the step of the patterned structure can be measured.

[Brief description of the drawings]

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

FIG. 2 is an explanatory view of light rays of the defect detection device of FIG.

FIG. 3 is a light beam explanatory diagram of the defect detection device of FIG.

FIG. 4 is a diagram showing an amplitude model of a reflected light beam.

FIG. 5 is a diagram showing an amplitude model of a reflected light beam.

FIG. 6 is a diagram showing an amplitude model of a reflected light beam.

FIG. 7 is a diagram showing an interference image between light beams having an phase difference of π / 2, which is an image obtained by epi-illumination.

FIG. 8 is a diagram showing an amplitude model of a light beam.

FIG. 9 is a diagram showing a light beam amplitude model.

FIG. 10: An image formed by epi-illumination and having a phase difference of -π /
FIG. 4 is a diagram showing an interference image between two light beams.

FIG. 11 is a schematic diagram of a waveform of an amplitude differential signal obtained from a signal based on an image obtained by epi-illumination.

FIG. 12 is a diagram schematically illustrating a waveform of an intensity image of an object under epi-illumination.

FIG. 13 is a diagram showing an outline of an intensity differential signal of an incident illumination object.

FIG. 14 is a diagram showing an amplitude model of a transmitted light beam.

FIG. 15 is a diagram schematically showing a waveform of an intensity image of an object under transmitted illumination.

FIG. 16 is a diagram schematically showing an intensity differential signal of transmitted illumination.

FIG. 17 is a view showing a visual field of a laser scanning differential interference microscope.

FIG. 18 is a diagram showing waveforms obtained by the defect detection device according to the first embodiment of the present invention.

FIG. 19 is a diagram showing waveforms obtained by the defect detection device according to the first embodiment.

FIG. 20 is a schematic configuration diagram of a defect detection device according to a second embodiment of the present invention.

FIG. 21 is a schematic diagram of an optical system of the defect detection device of FIG.

FIG. 22 is a schematic diagram of an optical system of the defect detection device of FIG.

FIG. 23 is a schematic configuration diagram of a defect detection device according to a third embodiment of the present invention.

FIG. 24 is a schematic diagram of an optical system of the defect detection device shown in FIG.

FIG. 25 is a schematic diagram of an optical system of the defect detection device shown in FIG.

FIG. 26 is a diagram showing a model of a reticle used in a simulation performed in the detailed description of the present invention.

FIG. 27 is a diagram showing a simulation waveform obtained by the defect detection device according to the fourth embodiment of the present invention.

FIG. 28 is a diagram showing a simulation waveform obtained by the defect detection device according to the fourth embodiment of the present invention.

FIG. 29 is a diagram showing a simulation waveform obtained by the defect detection device according to the fourth embodiment of the present invention.

FIG. 30 is a diagram showing a simulation waveform obtained by the defect detection device according to the fourth embodiment of the present invention.

FIG. 31 is a schematic configuration diagram of a defect detection device according to a fifth embodiment of the present invention.

FIG. 32 is a schematic diagram showing a circuit configuration of the defect detection device shown in FIG. 31.

FIG. 33 is a schematic configuration diagram of a defect detection device according to a sixth embodiment of the present invention.

FIG. 34 is a circuit configuration diagram of the defect detection device shown in FIG.

FIG. 35 is a diagram showing a method of determining the offset amount of the defect detection device shown in FIG. 33.

FIG. 36 is a schematic diagram of a waveform when an AC component of an interference image having a phase difference of π / 2 is subjected to an absolute value or its square in an epi-illumination.

FIG. 37 is a schematic diagram of a waveform when an AC component of an interference image having a phase difference of −π / 2 is subjected to an absolute value or its square in an incident illumination.

FIG. 38 is a schematic diagram of a waveform when an AC component of an interference image having a phase difference of −π / 2 is subjected to an absolute value or its square in an epi-illumination.

FIG. 39 is a diagram showing an outline of a second derivative similar waveform signal obtained from epi-illumination.

FIG. 40 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 33.

FIG. 41 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 33;

FIG. 42 is a diagram showing simulation waveforms in the defect detection device shown in FIG. 33.

FIG. 43 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 33;

FIG. 44 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 33;

FIG. 45 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 33;

FIG. 46 is a diagram showing simulation waveforms in the defect detection device shown in FIG.

FIG. 47 is a view showing a simulation waveform in the defect detection device shown in FIG. 33;

FIG. 48 is a view showing a simulation waveform in the defect detection device shown in FIG. 33;

FIG. 49 is a circuit configuration diagram of a defect detection device according to an embodiment of the present invention.

FIG. 50 is a diagram showing simulation waveforms in the defect detection device having the circuit configuration shown in FIG. 49;

FIG. 51 is a diagram showing simulation waveforms in the defect detection device having the circuit configuration shown in FIG. 49;

FIG. 52 is an overall configuration diagram of a defect detection device according to an embodiment of the present invention.

FIG. 53 is a diagram showing a circuit configuration of the defect detection device of FIG. 52;

FIG. 54 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 52;

FIG. 55 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 52;

FIG. 56 is a diagram showing a circuit configuration of a defect detection device according to an embodiment of the present invention.

FIG. 57 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 56.

FIG. 58 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 56;

FIG. 59 is an overall configuration diagram of a defect detection device according to an embodiment of the present invention.

60 is a circuit configuration diagram of the defect detection device shown in FIG. 59.

FIG. 61 is an overall configuration diagram of a defect detection device according to an embodiment of the present invention.

FIG. 62 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 61.

63 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 61.

FIG. 64 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 61.

FIG. 65 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 61.

FIG. 66 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 61.

FIG. 67 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 61.

FIG. 68 is an overall configuration diagram of a defect detection device according to an embodiment of the present invention.

FIG. 69 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 68.

70 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 68.

FIG. 71 is a diagram showing simulation waveforms in the defect detection device shown in FIG. 68.

FIG. 72 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 68.

FIG. 73 is an overall configuration diagram of a defect detection device according to an embodiment of the present invention.

74 is a diagram showing a circuit configuration of the defect detection device shown in FIG. 73.

FIG. 75 is a diagram showing characteristics of the primary differential signal.

FIG. 76 is a schematic configuration diagram of a registration measuring device to which the present invention is applied.

FIG. 77 is a schematic configuration diagram of an alignment system for a stepper to which the present invention is applied.

FIG. 78 is a schematic configuration diagram of a reticle coordinate measuring instrument to which the present invention is applied.

FIG. 79 is a schematic configuration diagram of a reticle coordinate measuring instrument to which the present invention is applied.

FIG. 80 is a schematic configuration diagram of a reticle appearance inspection apparatus to which the present invention is applied.

FIG. 81 is an explanatory diagram of a pattern position detection method according to an embodiment of the present invention.

FIG. 82 is a diagram showing signal waveforms obtained by simulation obtained by the pattern position detection method shown in FIG. 81; Diagram of simulation results according to the embodiment of the present invention

FIG. 83 is a diagram showing a simulation waveform in the defect detection device shown in FIG. 61;

FIG. 84 shows a simulation waveform in the defect detection device shown in FIG. 68. :

[Explanation of symbols]

Reference Signs List 1 light source 8 reticle 14, 63 polarizing beam splitter 45, 62 at analyzer angle 45, 62 polarizing beam splitter 17, 18, 48, 49, 51, 53, 56, 59 photoelectric conversion element 13, 6 Nomarski prism

Claims (140)

[Claims] A first light which is linearly polarized light having a first azimuth and which is obtained by irradiating a first position of an object to be inspected;
Light emitted from the same light source as the light obtained by irradiating the second position of the object to be inspected, which is different from the first position.
And a light beam generating unit that generates a second light obtained by irradiating linearly polarized light in a second direction to the position, and light that has passed through either one of reflection and transmission of the object to be inspected. A first analyzer having an analyzer angle in a direction in which the light obtained from the first light and the light obtained from the second light interfere with each other; and receiving the light obtained from the first analyzer. A first signal output unit that outputs a first signal obtained by performing the photoelectric conversion, and an analyzer angle that is different from an analyzer angle that is set for light incident on the first signal output unit. A second signal output unit that receives and obtains a light obtained from the first analyzer and outputs a second signal, and the first light that has passed through or reflected the object under test And photoelectrically converts the light, A third signal output unit that outputs a third signal obtained by the above-described method, and receives and photoelectrically converts the second light that has passed through either the transmitted or reflected light of the object to be inspected. A fourth signal output unit that outputs the obtained fourth signal; and a light receiving unit that receives the first light that has transmitted or reflected the other of the object to be inspected and performs photoelectric conversion on the first light. A fifth signal output unit that outputs the obtained fifth signal, and receives the second light that has passed through the other of the inspected object and the reflected second light, performs photoelectric conversion, and obtains the second light by the photoelectric conversion. A sixth signal output unit that outputs a sixth signal, and a difference between the first signal and the second signal,
A first differential output unit that outputs a first difference signal, and outputs a difference between the third signal and the fourth signal;
A second differential output unit that outputs a second difference signal; and outputs a difference between the fifth signal and the sixth signal.
A third differential output unit that outputs a third difference signal; and a desired signal using at least two types of signals from the first difference signal, the second difference signal, and the third difference signal. And a signal processing unit for outputting a signal, and observing a surface state of the object to be inspected. 2. The signal processing unit according to claim 1, further comprising a first primary differential output unit that outputs a first primary difference signal indicating a difference between the second difference signal and the third difference signal. The detection device according to claim 1, further comprising: 3. The signal processing section includes first amplifying means capable of arbitrarily changing a relative signal magnitude between the second difference signal and the third difference signal. 3. The detection device according to claim 2, wherein 4. The detecting device according to claim 3, wherein said first amplifying means makes the peak value of said second difference signal equal to the peak value of said third difference signal. 5. The signal processing unit according to claim 1, further comprising a first secondary differential output unit that outputs a difference between the first difference signal and the first primary difference signal. The detection device according to claim 2. 6. The signal processing section has a second amplifying means capable of arbitrarily changing a relative magnitude between the first difference signal and the first primary difference signal. The detection device according to claim 5, wherein 7. The apparatus according to claim 6, wherein said second amplifying means makes the peak value of said first difference signal equal to the peak value of said first primary difference signal. Detection device 8. The signal processing unit includes a second primary differential output unit that outputs a second primary difference signal indicating a difference between the first difference signal and the second difference signal. The detection device according to claim 1, further comprising: 9. The apparatus according to claim 1, wherein said signal processing unit includes third amplifying means capable of changing a relative signal magnitude between said first difference signal and said second difference signal. 9. The detection device according to claim 8, wherein: 10. The detecting device according to claim 9, wherein said third amplifying means sets the peak value of said first difference signal and the peak value of said second difference signal to the same value. 11. A third differential output unit for outputting a third primary difference signal indicating a difference between the second difference signal and the third difference signal. 9. The detection device according to claim 8, wherein 12. The signal processing unit further comprises: a fourth amplifying means capable of arbitrarily changing the relative signal magnitude between the second difference signal and the third difference signal. The detection device according to claim 11, wherein 13. The detection device according to claim 12, wherein said fourth amplifying means makes the peak value of said second difference signal equal to the peak value of said third difference signal. apparatus 14. A secondary differential output section for outputting a second secondary difference signal indicating a difference between the second primary difference signal and the third primary difference signal. The inspection or measurement device according to claim 11, further comprising: 15. A signal processing unit comprising: a fifth amplifying means capable of changing a relative signal magnitude between the second primary difference signal and the third primary differential signal. The detection device according to claim 14, further comprising: 16. The apparatus according to claim 16, wherein said fifth amplifying means sets the peak value of said second primary difference signal and the peak value of said third primary differential signal to the same value. 15. The detecting device according to 15. 17. The first signal output device, wherein the first analyzer is a polarization beam splitter having two analyzer angles in a direction in which interference with the first light and the second light is obtained. The light receiving element of the section receives the transmitted light of the polarization beam splitter, and the light receiving element of the second signal output section receives the reflected light of the polarization beam splitter. Inspection or measurement device according to any one of the above 18. A phase difference adjusting device for adjusting a phase difference between the first light and the second light incident on the first analyzer between the first analyzer and the object to be inspected. The detecting device according to claim 17, further comprising a member. 19. The detecting device according to claim 18, wherein said phase difference adjusting member is made of a transparent substance having a birefringence. 20. The phase difference adjusting member, comprising:
20. The detection device according to claim 19, wherein the detection device comprises a two-wave plate or a quarter-wave plate. 21. A light source, comprising: a light source that emits light having a plane of polarization in a specific direction; and light from the light source divided into the first light and the second light. 21. The detecting device according to claim 17, further comprising a light beam separating unit for irradiating the first position and the second position of the inspection object. 22. The method according to claim 19, further comprising: connecting the first object between the object to be inspected and the first analyzer and between the object to be inspected and the third and fourth signal output units. And a light beam combining means for combining the first light and the second light obtained by irradiating the first position and the second position on the same optical path. The detection device according to claim 21. 23. A detecting apparatus according to claim 22, wherein said light beam separating means and said light beam combining means are Wollaston prisms or Nomarski prisms. 24. A light source comprising: a laser light source for emitting light having a plane of polarization in a specific direction; and light beam scanning means for two-dimensionally scanning the light from the laser light source. 22. The detection device according to claim 21, 25. A light source comprising: a non-polarized lamp; and a polarizer for selecting only light having a plane of polarization in a specific direction from light obtained from the lamp. 22. The detection device according to claim 21, 26. A second light source having an analyzer angle in a direction in which interference with the first light and the second light, which are light that has passed through either the reflection or the transmission of the object to be inspected, is obtained. An analyzer, a seventh signal output unit that receives light obtained from the second analyzer, performs photoelectric conversion, and outputs a seventh signal obtained, and is incident on the seventh signal output unit. An analyzer angle set to light, an eighth signal output unit that receives and obtains light obtained from the second analyzer set to a different analyzer angle, and outputs an eighth signal; And the difference between the eighth signal and the eighth signal.
A fourth differential output unit that outputs a fourth difference signal, wherein the signal processing unit includes the first difference signal, the second difference signal, the third difference signal, and the fourth difference signal. 2. The detection device according to claim 1, wherein a desired signal is output using at least two types of signals among the difference signals. 27. A signal processing unit, comprising: a fourth primary differential output unit that outputs a fourth primary difference signal indicating a difference between the second difference signal and the third difference signal. The detection device according to claim 26, wherein the detection device is provided. 28. The signal processing section further comprises: sixth amplifying means capable of arbitrarily changing the relative signal magnitude between the second difference signal and the third difference signal. The detection device according to claim 27, characterized in that: 29. A detecting apparatus according to claim 28, wherein said sixth amplifying means makes the peak value of said second difference signal equal to the peak value of said third difference signal. 30. The signal processing section further comprises a third secondary differential output section for outputting a difference between the fourth difference signal and the fourth primary difference signal. A detection device according to claim 27. 31. A signal processing unit comprising: a seventh amplifying means capable of arbitrarily changing a relative magnitude between the fourth difference signal and the fourth primary difference signal. 31. The detecting device according to claim 30, wherein 32. The seventh amplifying means, wherein the peak value of the fourth difference signal and the peak value of the fourth primary difference signal are set to the same value. Detection device 33. A signal processing unit comprising: a fourth secondary differential output unit that outputs a difference between the first difference signal and the fourth primary difference signal; and the third secondary difference signal. 31. The detection device according to claim 30, further comprising: a determination unit configured to determine presence / absence of a defect from respective outputs of the dynamic output unit and the fourth secondary differential output unit. 34. A signal processing section, comprising: a fifth primary differential output section that outputs a fifth primary difference signal indicating a difference between the third difference signal and the fourth difference signal. The detection device according to claim 26, wherein the detection device is provided. 35. An apparatus according to claim 35, wherein said signal processing section includes an eighth amplifying means capable of changing a relative signal magnitude between said third difference signal and said fourth difference signal. 35. The detection device according to claim 34, wherein: 36. A detecting apparatus according to claim 35, wherein said eighth amplifying means makes the peak value of said third difference signal equal to the peak value of said fourth difference signal. 37. A signal processing unit, comprising: a sixth primary differential output unit that outputs a sixth primary difference signal indicating a difference between the second difference signal and the third difference signal. 35. The detection device according to claim 34, further comprising: 38. The signal processing section includes ninth amplifying means capable of arbitrarily changing the relative signal magnitude between the second difference signal and the third difference signal. 38. The detection device according to claim 37, wherein: 39. The detection according to claim 38, wherein said ninth amplifying means makes the peak value of said second difference signal equal to the peak value of said third difference signal. apparatus 40. A fifth secondary difference signal for outputting a fifth secondary difference signal indicating a difference between the fifth primary difference signal and the sixth primary difference signal. The detection device according to claim 37, further comprising a dynamic output unit. 41. A tenth amplifying means capable of arbitrarily changing a relative signal magnitude between said fifth primary difference signal and said sixth primary difference signal. 41. The detection device according to claim 40, comprising: 42. The tenth amplifying means, wherein:
42. The detecting apparatus according to claim 41, wherein the peak value of the second-order difference signal and the peak value of the sixth primary difference signal are set to the same value. 43. A signal processing unit, comprising: a seventh signal indicating a difference between the first difference signal and the second difference signal.
A first-order differential output unit that outputs a first-order difference signal, and a sixth-order difference signal indicating a difference between the sixth-order difference signal and the seventh-order difference signal. A sixth secondary differential output unit for outputting, and a determination unit for determining presence / absence of a defect from respective outputs of the fifth secondary differential output unit and the sixth secondary differential output unit. 41. The detection device according to claim 40, further comprising: 44. The second analyzer, wherein the second analyzer is a second polarizing beam splitter having an analyzer angle in a direction in which interference between the first light and the second light is obtained, wherein the seventh signal The light receiving element of the output unit receives the transmitted light of the second polarization beam splitter, and the light receiving element of the eighth signal output unit receives the reflected light of the polarization beam splitter. The inspection or measurement device according to any one of items 26 to 43. 45. A phase difference adjusting device for adjusting a phase difference between the first light and the second light incident on the second analyzer between the second analyzer and the object to be inspected. The detection device according to claim 44, further comprising a member. 46. The detecting device according to claim 45, wherein said phase difference adjusting member is made of a transparent substance having a birefringence. 47. The phase difference adjusting member comprises a rotatable 1 /
The detection device according to claim 45, wherein the detection device is formed of a two-wave plate or a quarter-wave plate. 48. The light beam generating unit, wherein a light source that emits light having a plane of polarization in a specific direction, and light from the light source are split into the first light and the second light, 48. The detecting apparatus according to claim 44, further comprising a light beam separating unit for irradiating the first position and the second position of the object to be inspected. 49. The method according to claim 49, further comprising: connecting the first object between the object to be inspected and the second analyzer and between the object to be inspected and the seventh and eighth signal output units. And a light beam combining means for combining the first light and the second light obtained by irradiating the first position and the second position on the same optical path. The detection device according to claim 48. 50. A detecting apparatus according to claim 49, wherein said light beam separating means and said light beam combining means are Wollaston prisms or Nomarski prisms. 51. A first light, which is linearly polarized light in a first direction and is obtained by irradiating a first position of the object to be inspected, and a light obtained by irradiating the first position. A second light, which is light emitted from the same light source and is obtained by irradiating a second position of the object to be inspected, which is different from the first position, with linearly polarized light in a second direction A light beam generating unit, and an analyzer in a direction in which light obtained from the first light and light obtained from the second light, which is light that has passed through either the reflection or the transmission of the object to be inspected, interfere with each other. An analyzer having an angle, a first signal output unit that receives light obtained from the analyzer and outputs a first signal obtained by performing photoelectric conversion, and is incident on the first signal output unit. The analyzer angle set different from the analyzer angle set to the light A second signal output unit that receives a light obtained from the narizer and outputs a second signal to be obtained, and that performs photoelectric conversion on the first light generated by the light beam generation unit, and obtains the first light by the photoelectric conversion. A third signal output unit that outputs the obtained third signal, and a third signal that photoelectrically converts the second light generated by the light beam generation unit and outputs a fourth signal obtained by the photoelectric conversion. 4, a pseudo signal output unit that combines the first signal and the second signal to output a desired pseudo signal, and calculates a difference between the first signal and the second signal. A first differential output unit for generating and outputting a first difference signal, and a second differential signal for generating and outputting a second difference signal indicating a difference between the third signal and the fourth signal. And at least one of the first difference signal, the second difference signal and the pseudo signal One of the basis of the signal, the detecting apparatus characterized by comprising a signal processing unit for outputting a signal showing the surface state of the object to be inspected 52. The pseudo signal output section, comprising: an offset signal applying section for applying a desired offset signal to each of the first signal and the second signal; and the offset signal applied by the offset applying section. A code conversion unit that replaces a minus component generated by the offset signal applying unit with a plus code for each of the first signal and the second signal; and the first signal output by the code conversion unit and the code conversion unit. Second
52. A detection device according to claim 51, further comprising: a pseudo signal generation unit that performs a synthesis process from the signal of (a) and outputs a pseudo signal. 53. The offset signal applying means, wherein a value of an output signal becomes 0 at a position estimated as an edge of a detection target of the inspection object field based on a waveform of the first signal. A first offset applying unit that applies an offset signal to the first signal; and a first output unit that outputs an output signal at a position estimated as an edge of a detection target on the inspection object based on a waveform of the second signal. 53. The detection apparatus according to claim 52, further comprising: a second offset applying unit that applies a second offset signal having a value of 0 to the second signal. 54. The apparatus according to claim 53, wherein the code converter outputs a signal squared to each of the first signal and the second signal output from the offset signal applying means. Detector described 55. The code conversion section outputs a signal obtained by taking an absolute value of each of the first signal and the second signal output from the offset signal applying means. A detection device according to claim 53. 56. A pseudo signal differential output for outputting the pseudo signal by indicating a difference between the first signal and the second signal output by the code conversion section. 53. The detecting device according to claim 52, further comprising a unit. 57. An apparatus according to claim 56, further comprising: a pseudo signal amplifying unit capable of arbitrarily changing a relative magnitude of said first signal and said second signal output from said code conversion unit. Detector described 58. A signal processing unit, comprising: a first primary differential output unit that outputs a first primary difference signal indicating a difference between the first difference signal and the second difference signal. The detection device according to claim 51, further comprising: 59. The signal processing unit further comprises first amplifying means capable of arbitrarily changing a peak value of a relative signal between the first difference signal and the second difference signal. The detection device according to claim 58, wherein: 60. A detecting apparatus according to claim 59, wherein said first amplifying means makes the peak values of said first difference signal and said second difference signal the same value. 61. A signal processing section comprising a first secondary differential output section for outputting a first secondary difference signal indicating a difference between the first primary difference signal and the pseudo signal. The detection device according to claim 58, wherein 62. The signal processing section further comprises second amplifying means capable of arbitrarily changing a peak value of a relative signal between the first primary difference signal and the pseudo signal. 62. The detection device according to claim 61, 63. A detecting apparatus according to claim 62, wherein said second amplifying means makes the peak value of said first primary difference signal and said pseudo signal the same value. 64. The detecting apparatus according to claim 58, wherein said signal processing section outputs a second primary difference signal indicating a difference between said second difference signal and said pseudo signal. 65. A signal processing unit comprising a third amplifying means capable of arbitrarily changing a peak value of a relative signal between the second difference signal and the pseudo signal. A detection device according to claim 64. 66. A detecting apparatus according to claim 65, wherein said third amplifying means sets the peak value of said second difference signal and said peak value of said pseudo signal to the same value. 67. A polarization beam splitter having two analyzer angles in a direction in which interference between the first light and the second light is obtained, and wherein the light is received by the first signal output unit. 67. The device according to claim 51, wherein the element receives the transmitted light of the polarizing beam splitter, and the light receiving element of the second signal output unit receives the reflected light of the polarizing beam splitter. Inspection or measurement device according to item 1. 68. A phase difference adjusting member for adjusting a phase difference between the first light and the second light incident on the analyzer between the analyzer and the object to be inspected. The detection device according to claim 67, characterized in that: 69. A detecting device according to claim 68, wherein said phase difference adjusting member is made of a transparent substance having a birefringence. 70. The phase difference adjusting member, wherein the rotatable 1 /
70. The detecting device according to claim 69, comprising a two-wave plate or a quarter-wave plate. 71. A light source that emits light having a plane of polarization in a specific direction, and divides light from the light source into the first light and the second light. 71. The detecting device according to claim 67, further comprising a light beam separating unit for irradiating the first position and the second position of the object to be inspected. 72. The first position and the first position between the object to be inspected and the analyzer, and between the object to be inspected and the third signal output unit and the fourth signal output unit. 72. A light beam combining means for combining the first light and the second light obtained by irradiating the second position on the same optical path. Detector described in item 73. A detecting apparatus according to claim 72, wherein said light beam separating means and said light beam combining means are Wollaston prisms or Nomarski prisms. 74. A light source comprising: a laser light source for emitting light having a plane of polarization in a specific direction; and light beam scanning means for two-dimensionally scanning light from the laser light source. 73. The detection device according to claim 71, 75. A light source comprising: a non-polarized lamp; and a polarizer that selects only light having a plane of polarization in a specific direction from light obtained from the lamp. 73. The detection device according to claim 71, 76. A first signal obtained by irradiating a first position of an object to be inspected and passing through either one of reflection and transmission of the object to be inspected and photoelectrically converting the light, and obtaining the first signal by the photoelectric conversion A first signal output unit for outputting the light emitted from the same light source and reflecting or transmitting the object to be inspected at a position different from the first position. A second signal output unit that receives light that has passed through any one of them, performs photoelectric conversion, and outputs a second signal obtained by the photoelectric conversion, and combines the first signal and the second signal. Desired first
A first pseudo-signal output unit that outputs a pseudo-signal of: a signal indicating a surface state of the inspection object by using at least a signal based on the first signal or the second signal and the pseudo signal Detecting device, comprising: 77. The first pseudo signal output section, wherein:
An offset signal applying unit for applying a desired offset signal to each of the signal and the second signal; and applying the offset to the first signal and the second signal, respectively, A code conversion unit that replaces one of the negative component and the positive component generated by the offset signal applying unit with a reverse polarity, and a combining process from the first signal and the second signal output by the code conversion unit. The detection apparatus according to claim 76, further comprising: a pseudo signal generation unit that outputs a pseudo signal. 78. The offset signal applying means, wherein a value of an output signal becomes 0 at a position estimated as a detection target edge of the inspection object field based on a waveform of the first signal. A first offset applying unit that applies an offset signal to the first signal; The detection device according to claim 77, further comprising: a second offset application unit that applies a second offset signal having a value of 0 to the second signal. 79. The code conversion section, wherein the first signal and the second signal output from the offset signal applying means are provided.
The detection apparatus according to claim 78, wherein a signal obtained by squaring each of the signals is output. 80. The code conversion section, wherein the first signal and the second signal output from the offset signal applying means are provided.
The detection device according to claim 78, wherein a signal obtained by taking an absolute value of each of the signals is output. 81. A first pseudo signal output section for outputting the pseudo signal indicating a difference between the first signal and the second signal output by the code conversion section. The detection device according to claim 80, further comprising: 82. The pseudo signal output unit includes a pseudo signal amplification unit that can arbitrarily change a peak value of a relative signal between the first signal and the second signal output from the code conversion unit. Preparation 83. The signal processing unit further includes a first differential output unit that outputs a first difference signal indicating a difference between the first signal and the second signal. 77. The detection device according to claim 76, 84. The signal processing unit includes a first secondary differential output unit that outputs a first secondary difference signal indicating a difference between the first difference signal and the pseudo signal. 84. The detection device according to claim 83, wherein: 85. The signal processing section further comprises first amplifying means for relatively changing the magnitude of the peak value of the signal between the first difference signal and the pseudo signal. Item 84. The detection device according to Item 84. 86. A detecting apparatus according to claim 85, wherein said first amplifying means makes the peak value of said first difference signal and said pseudo signal the same value. 87. A first light obtained by irradiating light emitted from the same light source to a first position of the object to be inspected, and a second light at a second position of the object to be inspected. A light beam generating unit that divides the light into a second light beam obtained by irradiating the light beam with linearly polarized light in the direction; a first light beam generated by the light beam splitting unit;
First light combining means for making the same light beam the same light flux, and the first light and the second light combined by the light combining means.
Beam splitting means for separating the light in a direction in which a first light receiving element serving as the first signal output unit and a second light receiving element serving as the second signal output unit, each of which performs photoelectric conversion, The detection device according to claim 83, further comprising: 88. A third light which is irradiated on the first position of the object to be inspected by the light beam generating means and reflects or transmits the object to be inspected, and the light beam generating means. Irradiating a second position of the object to be inspected with the fourth light that has passed through the other one of reflection and transmission of the object to be inspected to make the same light flux second light combining means; A second beam splitter that separates the third light and the fourth light into directions in which a third signal output unit and a fourth signal output unit for performing photoelectric conversion are arranged, respectively; A second pseudo signal output unit that combines the third signal and the fourth signal to output a desired second pseudo signal, and further includes the third signal and the third signal in the signal processing unit. The fourth
The detection device according to claim 87, further comprising a second differential output unit that outputs a second difference signal indicating a difference between the signals. 89. The second pseudo signal output unit, comprising:
Second offset signal applying means for applying a desired offset signal to each of the third signal and the fourth signal; and the third signal and the fourth signal to which an offset has been applied by the second offset applying means. A second code conversion unit that replaces one of the negative component and the positive component generated by the second offset signal applying unit with the opposite polarity, and a signal output from the second code conversion unit. The detection device according to claim 88, further comprising: a second pseudo signal generation unit configured to perform a synthesis process from the third signal and the fourth signal and output a second pseudo signal. 90. The second offset signal applying means, based on a waveform of the third signal, has a value of an output signal of 0 at a position estimated as an edge of a detection target of the inspection object field. A third offset applying unit that applies a third offset signal to the third signal, and a position at a position estimated as an edge of a detection target on the inspected object based on a waveform of the fourth signal. The detection device according to claim 89, further comprising: a fourth offset application unit configured to apply a fourth offset signal having an output signal value of 0 to the fourth signal. 91. The second code conversion section outputs a signal squared to each of the third signal and the fourth signal output from the second offset signal applying means. 90. The detection device according to claim 90, wherein: 92. The second code converter outputs a signal obtained by taking an absolute value of each of the third signal and the fourth signal output from the second offset signal applying means. The detection device according to claim 90, wherein the detection is performed. 93. The second pseudo signal generating section outputs the second pseudo signal indicating a difference between the third signal and the fourth signal output from the code conversion section. 2
90. A pseudo-signal output unit comprising:
Detector described 94. The second pseudo signal output section, wherein:
The third signal output from the code conversion unit of
The second signal which can arbitrarily change the relative signal peak value of the signal
10. A pseudo signal amplifying means according to claim 9.
3. Detection device according to 3. 95. The signal processing unit further comprises: a secondary differential output unit that outputs a secondary difference signal indicating a difference between the first difference signal and the second difference signal; A second pseudo signal generating unit that outputs a synthesized pseudo signal obtained by synthesizing the pseudo signal and the second pseudo signal, and a third differential output unit that outputs a difference between the second difference signal and the synthesized pseudo signal. The detection device according to claim 89, further comprising: 96. The signal processing unit further comprises second amplifying means for changing a relative magnitude of a signal between the first difference signal and the second difference signal. The detection device according to claim 95. 97. A detecting apparatus according to claim 96, wherein said second amplifying means sets the peak value of the signal between said first difference signal and said second difference signal to the same value. 98. The signal processing unit further comprises a third pseudo signal amplifying unit for changing a relative peak value of the first pseudo signal and the second pseudo signal. The detection device according to claim 95. 99. The third pseudo signal amplifying section, wherein:
The detection device according to claim 98, wherein the peak value of the pseudo signal of the second signal is equal to the peak value of the second pseudo signal. 100. The signal processing unit according to claim 95, wherein said signal processing unit further comprises third amplifying means for relatively changing the peak value of the signal of said second-order difference signal and said synthesized pseudo signal. Detector 101. A detecting apparatus according to claim 100, wherein said third amplifying means further makes the peak value of the signal of the second-order difference signal and the peak value of the signal of the synthesized pseudo signal the same. 102. The signal processing section further comprises: a secondary pseudo signal generating section for outputting a synthesized pseudo signal obtained by synthesizing the first pseudo signal and the second pseudo signal; 90. A secondary differential output unit for outputting a difference from the synthesized pseudo signal.
Detector described 103. The signal processing section further comprises a third pseudo signal amplifying section for changing a relative peak value of the signal between the first pseudo signal and the second pseudo signal. 103. The detection device according to claim 102. 104. The detecting apparatus according to claim 103, wherein said third pseudo signal amplifying unit makes the peak values of said first pseudo signal and said second pseudo signal the same value. 105. The signal processing unit according to claim 10, further comprising third amplification means for relatively changing the peak value of the signal between the first difference signal and the synthesized pseudo signal.
2. Detection device according to 2. 106. The third amplifying means further comprises the first amplifying means.
106. The detection apparatus according to claim 105, wherein the peak value of the signal of the difference signal of the signal and the peak value of the signal of the combined pseudo signal are set to the same value. 107. A light source that emits light having a polarization plane in a specific direction, and light from the light source is divided into first light and second light having different polarization directions, respectively. A beam separating unit for irradiating a first position and a second position, and the first light obtained by irradiating the first position and the second position of the inspection object, respectively. Light beam combining means for combining the second light beam and the second light beam on the same optical path; and each of the first light beams obtained by irradiating the first position and the second position of the inspection object. First phase difference adjusting means for giving a desired phase difference between the first light and the second light; and interference between the first light and the second light passing through the first phase difference adjusting means. A first polarizing beam splitter having two types of analyzer angles in the directions to be inspected; The phase difference provided by the first phase difference adjusting means between each of the first light and the second light obtained by irradiating the first position and the second position is different from each other. A second phase difference adjusting means for providing a phase difference; and a second phase angle adjusting means having two types of analyzer angles in a direction in which interference between the first light and the second light having passed through the second phase difference adjusting means is obtained. A first polarization beam splitter, a first signal generator that outputs a first signal by photoelectrically converting transmitted light of the first polarization beam splitter, and a photoelectric conversion unit that reflects reflected light of the first polarization beam splitter. A second signal generation unit that outputs a second signal by converting the signal, a third signal generation unit that outputs a third signal by photoelectrically converting light transmitted through the second polarization beam splitter, The reflected light of the second polarizing beam splitter A fourth signal generation unit that outputs a fourth signal by conversion, and a first difference signal output unit that outputs a first difference signal indicating a difference between the first signal and the second signal. A pseudo signal output unit that combines the third signal and the fourth signal to output a desired pseudo signal; and at least the first difference signal and the pseudo signal, A signal processing unit that outputs a signal indicating a surface shape. 108. The pseudo signal output section, wherein an offset signal applying means for applying a desired offset signal to each of the third signal and the fourth signal, and an offset signal is applied by the offset applying means. A code conversion unit that replaces, in each of the third signal and the fourth signal, one of a negative component and a positive component generated by the offset signal applying unit with a reverse polarity; and the code conversion unit. 108. The detection apparatus according to claim 107, further comprising: a pseudo signal generation unit that performs a synthesis process on the output third signal and the fourth signal to output a pseudo signal. 109. The third offset signal applying means, wherein a value of an output signal becomes 0 at a position estimated as an edge of a detection target in the inspection object field based on a waveform of the third signal. A third offset applying unit configured to apply an offset signal to the third signal; and 109. The detecting apparatus according to claim 108, further comprising: a fourth offset applying unit that applies a fourth offset signal having a value of 0 to the fourth signal. 110. The code conversion section outputs a signal squared to each of the third signal and the fourth signal output from the offset signal applying means. Detector described 111. The code converter outputs a signal obtained by taking an absolute value of each of the third signal and the fourth signal output from the offset signal applying means. 109. The detection device according to claim 108. 112. A pseudo signal differential output for outputting said pseudo signal, wherein said pseudo signal generation section indicates a difference between said third signal and said fourth signal output by said code conversion section. 109. The detection device according to claim 108, further comprising a unit. 113. The pseudo signal generating section includes a pseudo signal amplifying section that arbitrarily changes the relative magnitude of the third signal and the fourth signal output from the code conversion section. The detection device according to claim 112, wherein 114. The detection according to claim 113, wherein said pseudo signal amplifying unit makes the peak values of said third signal and said fourth signal output by said code converting unit the same. apparatus 115. The signal processing section has a primary differential output section for outputting a primary difference signal indicating a difference between the first difference signal and the pseudo signal.
Detector described 116. The signal processing unit according to claim 115, further comprising a first amplifying unit for arbitrarily changing a relative magnitude of a signal between the first difference signal and the pseudo signal.
Detector described 117. The detecting apparatus according to claim 116, wherein said first amplifying unit makes the peak value of said first difference signal and said pseudo differential signal the same value. 118. A light irradiating unit for irradiating light to an object to be inspected, and photoelectrically converting either light transmitted or reflected by the object to be inspected obtained by irradiating light output from the light irradiating unit A first light receiving unit that generates and outputs a first signal; a first signal delay unit that generates and outputs a second signal by delaying the first signal; And a first differential output unit that generates and outputs a first difference signal that is a difference from the second signal, and a first pseudo signal based on the first signal and the second signal. A first pseudo-signal output unit that generates and outputs a signal, based on the first difference signal and the first pseudo signal,
A signal processing unit that outputs a signal indicating a surface state of the object to be inspected. 119. A first pseudo signal output unit, comprising: a first offset applying unit that receives the first signal and outputs a signal representing a difference between the first signal and a first offset signal. A second offset application unit that receives the second signal and outputs a signal representing a difference between the second signal and a second offset signal; and an offset signal is applied by the first offset application unit. A first code conversion unit that replaces one of a generated negative component signal and a positive component signal with an opposite polarity to the first signal, and an offset signal is applied by the second offset application unit. The second signal, a second code conversion unit that replaces one of the generated negative component signal and the positive component signal with a reverse polarity, and a signal output from the first code conversion unit. The second code Receiving the signal output from the conversion unit and generating and outputting the pseudo signal from the signal output from the first code conversion unit and the signal output from the second code conversion unit The detection device according to claim 118, further comprising: a generation unit. 120. The first offset applying section, wherein the value of an output signal at a position estimated as an edge of a detection target on the inspected object is 0 based on a waveform of the first signal. The first offset signal is applied, and the second offset application unit outputs a value of an output signal at a position estimated to be green of the detection target on the inspection object based on a waveform of the second signal. 120. The detection apparatus according to claim 119, wherein the second offset signal which becomes 0 is applied. 121. The first code conversion section outputs the square of the value of the signal output from the first offset application section, and the second code conversion section outputs the second offset application signal. 121. The detection device according to claim 120, wherein a square of a value of the signal output from the unit is output. 122. The first code conversion section outputs an absolute value of a value of a signal output from the first offset application section, and the second code conversion section outputs the absolute value of the second offset application section. The detection device according to claim 120, wherein an absolute value of a value of the signal output from the unit is output. 123. A pseudo signal generating section for outputting a pseudo differential signal indicating a difference between a signal output from the first code conversion section and a signal output from the first code conversion section. 120. The detection device according to claim 119, further comprising a signal differential output unit. 124. A second signal for generating and outputting a third signal by photoelectrically converting either light transmitted or reflected by the object to be inspected by irradiation of light output from the light irradiation unit. A second signal delayer that delays the third signal and generates and outputs a fourth signal; and a second signal that is a difference between the third signal and the fourth signal. A second differential output unit that generates and outputs a difference signal; and a second pseudo signal output that generates and outputs a second pseudo signal based on the third signal and the fourth signal. A second pseudo-signal output unit that outputs a second pseudo-differential signal based on the third pseudo signal and the fourth pseudo signal, and outputs the second pseudo-differential signal. And outputting a signal indicating a surface state of the object to be inspected based on the difference signal of 2 and the secondary pseudo signal. No. processor and detection apparatus Izure or one of claims 118 to 123 comprising the 125. A second pseudo signal output unit, comprising: a third offset applying unit that receives the third signal and outputs a signal representing a difference between the third signal and a third offset signal. A second offset applying unit that receives the fourth signal and outputs a signal representing a difference between the fourth signal and a fourth offset signal; and an offset signal is applied by the third offset applying unit. A third code conversion unit that replaces one of the generated negative component signal and the positive component signal with an opposite polarity to the third signal, and an offset signal is applied by the fourth offset application unit. A fourth code conversion unit that replaces one of the generated negative component signal and the positive component signal with the opposite polarity to the fourth signal, and a signal output from the third code conversion unit. Fourth sign change And a pseudo-signal generator that receives and outputs the pseudo-signal from the signal output from the third code converter and the signal output from the fourth code converter. 125. The detection device according to claim 124, further comprising a unit. 126. The third offset applying section, wherein a value of an output signal at a position estimated as an edge of a detection target on the inspection object based on a waveform of the third signal becomes 0. The third offset signal is applied, and the fourth offset applying unit adjusts a value of an output signal at a position estimated as an edge of a detection target on the inspection object based on a waveform of the fourth signal. 126. The detection device according to claim 125, wherein the fourth offset signal that becomes 0 is applied. 127. The third code conversion section outputs the square of the value of the signal output from the third offset application section, and the fourth code conversion section outputs the fourth offset application signal. The detection device according to claim 125, wherein the detection device outputs a square of a value of the signal output from the unit. 128. The first code conversion section outputs an absolute value of a value of a signal output from the first offset application section, and the second code conversion section outputs the absolute value of the second offset application section. The detection device according to claim 125, wherein the detection device outputs an absolute value of a value of a signal output from the unit. 129. The pseudo signal generation section generates a pseudo differential signal that is a difference between a signal output from the first code conversion section and a signal output from the first code conversion section. The detection device according to claim 125, further comprising a pseudo signal differential output unit for outputting. 130. The secondary pseudo-differential signal output section includes pseudo signal amplifying means for relatively varying the magnitude of the first pseudo signal and the second pseudo signal. The detection device according to claim 124, wherein 131. A first primary differential output for generating and outputting a first primary difference signal indicating a difference between the first difference signal and the second difference signal. A second differential output receiving and receiving a first differential signal and the second pseudo differential signal, generating and outputting a second difference signal indicating a difference between the first differential signal and the second pseudo differential signal; 125. The detection device according to claim 124, comprising: 132. The signal processing section further comprises a first amplifying section for relatively changing a peak value of the first difference signal and a peak value of the second difference signal. The detection device according to claim 131. 133. The detection according to claim 132, wherein the first amplifying unit sets the peak value of the first difference signal and the peak value of the second difference signal to the same value. apparatus 134. The signal processing section generates a second primary difference signal indicating a difference between any one of the first difference signal and the second difference signal and the secondary pseudo signal. 125. The detection device according to claim 124, further comprising a second primary differential output unit that outputs the data. 135. The signal processing section relatively changes a peak value of the one of the first difference signal and the second difference signal and a peak value of the second pseudo differential signal. 135. The detection device according to claim 134, further comprising a second amplifying unit configured to perform the operation. 136. The second amplifying section sets the peak value of one of the first difference signal and the second difference signal to the same value as the peak value of the second pseudo differential signal. 135. The detection device according to claim 135, wherein: 137. A light source for irradiating the inspection object with inspection light, a first signal generation unit for receiving the inspection light reflected from the inspection object, photoelectrically converting the inspection light, and outputting a first signal. A second signal generation unit that receives inspection light transmitted through the object to be inspected, photoelectrically converts the inspection light, and outputs a second signal; and a relative magnitude of the first signal and the second signal. And a signal processor for calculating a difference between the first signal and the second signal and subtracting a predetermined offset amount from the calculated difference. Characteristic detection device 138. The signal processing section includes at least one of the first signal and the second signal to set a relative magnitude relationship between the first signal and the second signal to a predetermined relationship. Amplifying means for amplifying the first signal with a predetermined gain; and
A differential output unit that outputs a difference between the second signal and the second signal, and an offset amount subtraction unit that outputs a difference between a signal output from the differential output unit and a DC signal corresponding to the offset amount. 137. The detecting device according to claim 137, further comprising: 139. A differential signal relating to an image of the object to be inspected is obtained, a desired signal component is selected and obtained from at least two types of signal components inherent in the differential signal, and a waveform of the selected signal component is obtained. Detecting an object present in the inspection object 140. A detection method according to claim 139, wherein said two kinds of signal components are secondary differential signal components different from a primary differential signal component and said phase differential signal.