JP4192370B2 - Inspection apparatus and inspection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inspection apparatus and an inspection method for inspecting the state of an inspection object by irradiating the inspection object with illumination light and observing the inspection object illuminated with the illumination light.
[0002]
[Prior art]
In general, in an inspection apparatus using an optical microscope, an inspection object is inspected by irradiating the inspection object with illumination light and optically detecting reflected light, scattered light, diffracted light, refracted light, and the like. I have to.
[0003]
In an inspection apparatus using this optical microscope, a vacuum is not required for inspection unlike an inspection apparatus using a scanning electron microscope (SEM) or an atomic force microscope (AFM). Further, there is an advantage that inspection can be performed in a short time without contact.
[0004]
In recent years, development of optical microscopes that use laser light as illumination light has been actively promoted, and expectations for inspection apparatuses using such optical microscopes are increasing. For example, if a laser beam having a wavelength in the deep ultraviolet region is used as illumination light, a semiconductor integrated circuit pattern that has been increasingly miniaturized in recent years can be inspected with high resolution and high precision, so a scanning electron microscope or the like was used. There is great expectation as an inspection device that replaces the inspection device.
[0005]
[Problems to be solved by the invention]
By the way, in an inspection apparatus using an optical microscope, as described above, the inspection object is irradiated with the illumination light to perform the inspection. Therefore, if the illumination light irradiation amount is not appropriate, the inspection object is damaged by the illumination light irradiation. May end up.
[0006]
Specifically, for example, when the examination target is a living tissue, irradiation with illumination light may cause tissue destruction or cell necrosis in the living tissue. Further, when the inspection object is a photosensitive material, the photosensitive material may be exposed to light by irradiation with illumination light. Further, when the inspection target is a resist pattern formed on a semiconductor wafer in a lithography process of a semiconductor process, the resist pattern may be contracted by irradiation with illumination light.
[0007]
Accordingly, the present invention provides an inspection apparatus and an inspection method that can appropriately inspect an inspection object without damaging the inspection object by adjusting the amount of illumination light irradiated to the inspection object to an appropriate value. The purpose is to provide.
[0008]
[Means for Solving the Problems]
An inspection apparatus according to the present invention is an inspection apparatus that observes an inspection object illuminated by illumination light and inspects the state of the inspection object, a light source that emits illumination light that illuminates the inspection object, and the light source. An illumination optical system that guides the emitted illumination light to the inspection target, and a light amount monitoring unit for monitoring the irradiation light amount of the illumination light irradiated on the inspection target are provided. In this inspection apparatus, shutter means for transmitting or blocking illumination light emitted from the light source is provided in the illumination optical system, and the illumination light irradiation light quantity monitored by the light quantity monitor means is provided for the shutter means. By controlling according to this, it is possible to adjust the irradiation light quantity of the illumination light irradiated to the inspection object.
[0009]
In this inspection apparatus, the illumination light emitted from the light source is guided to the illumination optical system and applied to the inspection object. As a result, the inspection object is illuminated by the illumination light. In this inspection apparatus, the state of the inspection object is inspected by observing the inspection object illuminated by the illumination light.
[0010]
Here, in this inspection apparatus, shutter means is provided in the illumination optical system, and illumination light emitted from the light source can be transmitted or blocked by the shutter means. Further, the irradiation light amount of the illumination light irradiated to the inspection object is monitored by the light amount monitoring means, and the illumination light is controlled by controlling the shutter means according to the irradiation light amount of the illumination light monitored by the light amount monitoring means. The amount of irradiation light can be adjusted.
[0011]
For example, if the amount of illumination light irradiated to the inspection object exceeds an irradiation threshold that damages the inspection object, the illumination light is adjusted by blocking the illumination light by the shutter means. Thus, it is possible to effectively prevent damage to the inspection target.
[0012]
As described above, in this inspection apparatus, the amount of illumination light irradiated to the inspection object can be adjusted to an appropriate value according to the inspection object, so that the inspection object is not damaged. Can be properly inspected.
[0013]
In addition, the inspection method according to the present invention guides the illumination light emitted from the light source to the inspection object by the illumination optical system, illuminates the inspection object, observes the inspection object illuminated by the illumination light, and When inspecting the state, the irradiation light amount of the illumination light irradiated to the inspection object is monitored using a light amount monitor unit, and a shutter unit that transmits or blocks the illumination light emitted from the light source is included in the illumination optical system. By arranging and controlling the shutter means in accordance with the irradiation light amount of the illumination light monitored by the light amount monitoring means, the irradiation light amount of the illumination light irradiated on the inspection object is adjusted.
[0014]
According to this inspection method, the amount of illumination light irradiated to the inspection object can be adjusted according to the inspection object, so that this inspection object can be appropriately inspected without damaging the inspection object. it can.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
One configuration example of an inspection apparatus to which the present invention is applied is shown in FIG. The inspection apparatus 1 shown in FIG. 1 is configured to inspect the state of a resist pattern formed on a semiconductor wafer in a lithography process of a semiconductor process, and is movable to support the semiconductor wafer 100 so as to be movable. A stage 2; a light source 3 that emits illumination light that irradiates a resist pattern formed on the semiconductor wafer 100; an illumination optical system that guides the illumination light emitted from the light source 3 to a resist pattern to be inspected; and the illumination optical system A shutter 4 that transmits or blocks the illumination light emitted from the light source 3, a light amount monitor 5 that monitors the amount of illumination light irradiated to the resist pattern, and a resist pattern illuminated by the illumination light. An image pickup device 6 for picking up an image, and reflected light from a resist pattern illuminated by illumination light. An imaging optical system for guiding the, the image processing computer 7 which processes the image of the resist pattern picked up by the imaging device 6, and a control unit 8 for controlling the operation of the entire inspection device 1.
[0017]
The movable stage 2 includes, for example, an X stage and a Y stage for moving the semiconductor wafer 100 installed on the movable stage 2 in the horizontal direction, a Z stage for moving the semiconductor wafer 100 in the vertical direction, and a semiconductor. A θ stage for rotating the wafer 100 and a suction plate for sucking and fixing the semiconductor wafer 100 onto the movable stage 2 are provided. Then, the movable stage 2 moves each of the above stages under the control of the control unit 7 to move a portion to be inspected of the semiconductor wafer 100 sucked by the suction plate to a predetermined inspection position.
[0018]
As the light source 3 that emits illumination light, for example, an ultraviolet solid laser is used. This ultraviolet solid-state laser converts the wavelength of a solid-state laser such as a YAG laser using a nonlinear optical crystal, and emits, for example, deep ultraviolet (DUV) laser light having a wavelength of about 266 nm.
[0019]
The inspection capability of the inspection apparatus depends on the wavelength of the illumination light applied to the inspection object, and a finer pattern can be inspected when the wavelength of the illumination light is shorter. In the inspection apparatus 1, an ultraviolet solid laser is used as the illumination light source 3, and the resist pattern to be inspected is illuminated with a short-wavelength deep ultraviolet laser beam, so that a fine pattern can be inspected. . In addition, the ultraviolet solid laser is excellent in handling because the device itself is small in size and does not require water cooling, and is optimal as the light source 3 of illumination light in the inspection device 1.
[0020]
For example, an acousto-optic modulator (AOM: Acoustic Optics Modulator) is used as the shutter 4 that transmits or blocks the illumination light emitted from the light source 3. This acousto-optic modulator is an optical modulator using an acousto-optic effect, and can modulate light electrically. The shutter 4 is connected to the control unit 8, and under the control of the control unit 8, the illumination light emitted from the light source 3 is transmitted or blocked to adjust the amount of irradiation light.
[0021]
As the shutter 4, any shutter 4 can be used as long as it can switch transmission / cutoff of illumination light emitted from the light source 3. For example, a spatial light modulator such as a liquid crystal panel using a liquid crystal material, a light diffraction shutter using a diffraction grating, a waveguide shutter using a photoelastic effect, or the like may be used.
[0022]
As the light amount monitor 5 for monitoring the irradiation light amount of the illumination light, for example, a CCD (charge-coupled device) camera for ultraviolet light configured so as to obtain high sensitivity to deep ultraviolet laser light is used. . The light amount monitor 5 is connected to an integration circuit 9, converts received illumination light into an electrical signal, and supplies the electrical signal to the integration circuit 9. The integrating circuit 9 calculates the integrated irradiation light amount of the illumination light from the electrical signal supplied from the light amount monitor 5 and supplies it to the control unit 8.
[0023]
As the light quantity monitor 5, any monitor may be used as long as the received illumination light can be converted into an electrical signal. For example, a phototransistor or a calorimeter may be used as the light amount monitor 5.
[0024]
As the image pickup element 6, for example, a high sensitivity CCD camera for ultraviolet light that can obtain a quantum efficiency of about 36% with respect to deep ultraviolet laser light having a wavelength of about 266 nm is used. As described above, if a CCD camera having high sensitivity to deep ultraviolet laser light is used as the image pickup element 6, it is possible to pick up a fine resist pattern image with high resolution. The image pickup device 6 is connected to an image processing computer 7. In this inspection apparatus 1, an image of a resist pattern imaged by the image imaging device 6 is taken into the image processing computer 7.
[0025]
The image pickup element 6 is preferably provided with a cooling mechanism. For example, when an ultraviolet light CCD camera is used as the image pickup element 5, it is desirable that the CCD chip be cooled to about 5 ° C. by a Peltier element. If the image pickup device 6 is cooled as described above, read noise and thermal noise generated when the image of the resist pattern picked up by the image pickup device 5 is transferred to the image processing computer 7 are greatly reduced. It becomes possible to reduce.
[0026]
In the inspection apparatus 1 configured as described above, the state of the resist pattern is inspected by processing and analyzing the image of the resist pattern captured by the image processing computer 7 by the image processing computer 7. .
[0027]
Here, a method for inspecting a resist pattern formed on the semiconductor wafer 100 using the inspection apparatus 1 will be described.
[0028]
When inspecting a resist pattern using the inspection apparatus 1, first, as shown in FIG. 2, the semiconductor wafer 100 on which the resist pattern 101 is formed is placed on the movable table 2. Then, the movable table 2 is driven under the control of the control unit 8 and the semiconductor wafer 100 is moved, whereby the resist pattern 101 at the location to be inspected is positioned at a predetermined inspection position.
[0029]
Next, the light source 3 is driven under the control of the control unit 8, and, for example, deep ultraviolet laser light having a wavelength of about 266 nm is emitted from the light source 3 as illumination light.
[0030]
The illumination light emitted from the light source 3 first passes through the variable ND filter (a neutral density filter) 11 and enters the condenser lens 12. Here, the variable ND filter 11 reduces the illumination light emitted from the light source 3 without changing the spectral composition.
[0031]
The illumination light incident on the condenser lens 12 is condensed by the condenser lens 12 and forms an image inside the shutter 4. The shutter 4 switches illumination light transmission / blocking under the control of the control unit 8. As a result, the amount of illumination light transmitted through the shutter 4, that is, the amount of illumination light irradiated onto the resist pattern 101 to be inspected is adjusted.
[0032]
The illumination light that has passed through the shutter 4 passes through the rotating diffusion plate 13 and enters the condenser lens 14. Here, the rotating diffusion plate 13 is for reducing speckle noise, which is a problem when laser light having good coherence is used as illumination light.
[0033]
The illumination light incident on the condenser lens 14 is collected by the condenser lens 14, passes through a Koehler illumination system constituted by the aperture stop 15, the field stop 16, and the condenser lens 17, and enters the polarization beam splitter 18.
[0034]
The illumination light incident on the polarization beam splitter 18 is separated into two linearly polarized components orthogonal to each other by the polarization beam splitter 18, one of which is reflected by the polarization beam splitter 18 and the other is transmitted through the polarization beam splitter 18. To do.
[0035]
The light of one linearly polarized component reflected by the polarization beam splitter 18 is converted into circularly polarized light by passing through the quarter-wave plate 19 and irradiated onto the resist pattern 101 to be inspected through the objective lens 20. The As a result, the resist pattern 101 is illuminated.
[0036]
In the inspection apparatus 1, an illumination optical system is configured by the optical elements from the variable ND filter 11 to the objective lens 20 described above.
[0037]
The light of the other linearly polarized light component transmitted through the polarization beam splitter 18 is incident on the light amount monitor 5 through the imaging lens 21 and is received by the light amount monitor 5. Here, the light of the other linearly polarized light component transmitted through the polarizing beam splitter 18 and received by the light amount monitor 5 is reflected by the beam splitter 18 under the condition that the polarization dependency of the light source 3 is constant, and is to be inspected. A proportional relationship is established with the light of one linearly polarized light component irradiated to the resist pattern 101. Therefore, if the correlation between these lights is obtained in advance, the amount of illumination light irradiated on the resist pattern 101 is obtained from the amount of light of the other linearly polarized light component received by the light amount monitor 5. Can do.
[0038]
The light quantity monitor 5 converts the received light into an electric signal and supplies the electric signal to the integrating circuit 9. Then, the integrating circuit 9 calculates the integrated irradiation light amount of the illumination light based on the electric signal supplied from the light amount monitor 5 and supplies it to the control unit 8.
[0039]
In this inspection apparatus 1, the control unit 8 controls the shutter 4 according to the integrated illumination light amount of the illumination light calculated by the integration circuit 9 to adjust the irradiation light amount of the illumination light. That is, when the integrated illumination light amount of the illumination light calculated by the integration circuit 9 approaches an irradiation threshold value that causes the resist pattern 101 to be inspected to contract, the control unit 8 closes the shutter 4 and illuminates the light. And the resist pattern 101 is not irradiated with illumination light. Thereby, the irradiation light quantity of the illumination light irradiated to the resist pattern 101 to be inspected can be adjusted to be equal to or less than the irradiation threshold value that causes the resist pattern 101 to contract. Further, the control unit 8 can also adjust the amount of illumination light irradiated to the resist pattern 101 by controlling the variable ND filter 11.
[0040]
Further, in this inspection apparatus 1, the control unit 8 can also control the opening / closing operation of the shutter 4 in the illumination optical system in synchronization with the shutter of the image pickup element 6 made of an ultraviolet CCD camera or the like. . In this way, if the opening / closing operation of the shutter 4 in the illumination optical system is controlled in synchronization with the shutter of the image pickup device 6, the illumination light can be efficiently irradiated onto the resist pattern 101 to be inspected.
[0041]
The reflected light from the resist pattern 101 illuminated by the illumination light passes through the objective lens 20 and enters the quarter-wave plate 19. Then, after being converted into linearly polarized light by the quarter-wave plate 19, the light enters the polarizing beam splitter 18 again. Here, since the reflected light from the resist pattern 101 that has entered the polarizing beam splitter 18 again is linearly polarized light that is orthogonal to the linearly polarized light previously reflected by the polarizing beam splitter 18, The light passes through the splitter 18.
[0042]
The reflected light from the resist pattern 102 that has passed through the polarizing beam splitter 18 enters the image pickup device 6 through the imaging lens 22. As a result, an image of the resist pattern 101 enlarged by the objective lens 20 as shown in FIG. 3 is picked up by the image pickup element 6.
[0043]
In the inspection apparatus 1, an imaging optical system is configured by the optical elements from the objective lens 20 to the imaging lens 22.
[0044]
Here, as the objective lens 20, for example, a high numerical aperture lens having a numerical aperture NA of about 0.9 is used. In this inspection apparatus 1, a short wavelength deep ultraviolet laser beam is used as illumination light, and a lens having a high numerical aperture is used as the objective lens 20, so that a finer pattern can be inspected. In addition, the objective lens 20 is provided with a measure to reduce aberrations with respect to ultraviolet light having a wavelength of about 266 nm, for example.
[0045]
In addition, the inspection apparatus 1 includes a focus control unit that adjusts the distance between the objective lens 20 and the resist pattern 101 to be inspected, that is, the focus state of the illumination light.
[0046]
In an inspection apparatus using an ordinary optical microscope, the distance between the objective lens 20 and the resist pattern 101 is measured by irradiating the inspection object with illumination light and detecting the reflected light, thereby adjusting the focus state. However, if the focus state is adjusted while irradiating illumination light to the inspection object, the illumination light at this time is also integrated as the irradiation light amount for the inspection object. Thus, if the illumination light amount is integrated by adjusting the focus state, the illumination light amount at the time of actual inspection is limited, which is very inefficient.
[0047]
Therefore, in this inspection apparatus 1, the capacitive sensor 23 is disposed in the vicinity of the objective lens 20, and the distance between the objective lens 20 and the resist pattern 101 is detected by the capacitive sensor 23, Based on this, the focus control means adjusts the focus state of the illumination light.
[0048]
Here, when the resist pattern 101 to be inspected is inclined in the height direction, or when the posture of the movable stage 2 that supports the semiconductor wafer 100 on which the resist pattern 101 is formed is not maintained with high accuracy, one resist pattern 101 is provided. If only the off-axis length measurement is performed by the capacitive sensor 23, an Abbe error may occur, and the distance between the objective lens 20 and the resist pattern 101 may not be accurately detected. In particular, in the inspection apparatus 1 that performs inspection with very high resolution using short-wavelength deep ultraviolet laser light as illumination light, a slight misalignment greatly affects the inspection accuracy. It is required to accurately detect the distance to the pattern 101. Therefore, in this inspection apparatus 1, length measurement is performed at a plurality of locations using a plurality of capacitance sensors 23 so that accurate focus adjustment can be performed. However, when the attitude of the movable stage 2 is maintained with high accuracy and the resist pattern 101 is not tilted, no Abbe error occurs even if off-axis length measurement is performed by one capacitance type sensor 23. The distance between the objective lens 20 and the resist pattern 101 can be accurately detected. Therefore, in such a case, length measurement may be performed by one capacitance type sensor 23.
[0049]
The method for detecting the distance between the objective lens 20 and the resist pattern 101 to be inspected is not limited to the example using the capacitance type sensor 23 as described above. A meter, an eddy current displacement meter, a displacement meter using an atomic force probe, a pneumatic displacement meter, or the like may be used. In addition, by using light that is not integrated as the illumination light amount, for example, light that does not damage the inspection target at a wavelength different from the illumination light, irradiating the inspection target with this light, and detecting the reflected light, You may make it measure the distance between the objective lens 20 and test object. Moreover, you may make it use combining the above methods.
[0050]
The image of the resist pattern 101 picked up by the image pickup device 6 is taken into the image processing computer 7. The image processing computer 7 processes the captured image of the resist pattern 101, thereby creating a light intensity profile as shown in FIG.
[0051]
The intensity profile shown in FIG. 4 is obtained when the illumination light diffracted by the resist pattern 101, which is a concavo-convex pattern, interferes near the step, and corresponds to the concavo-convex pattern of the resist pattern 101. Yes. That is, the large peak portion (portion a in FIG. 4) that appears in the intensity profile corresponds to the concave portion of the resist pattern 101, and the portion between the two large peaks (portion b in FIG. 4) This corresponds to the convex portion of the resist pattern 101. In the intensity profile, a small mountain appears between two large mountains, and a peak that becomes a valley appears between the small mountain and the large mountain. The peak that becomes the valley corresponds to a boundary portion (hereinafter referred to as a pattern edge) between the concave portion and the convex portion of the resist pattern 101.
[0052]
In the inspection apparatus 1 to which the present invention is applied, as described above, an intensity profile in which a trough peak appears corresponding to the pattern edge of the resist pattern 101 can be obtained. From this intensity profile, the width of the convex portion of the resist pattern 101 is obtained. (Line width) can be measured. That is, in the intensity profile obtained by the inspection apparatus 1, the interval between the peaks that are two valleys corresponds to the width of the convex portion. Therefore, if the distance between the peaks that are these two valleys is obtained, the resist pattern 101 is obtained. Can be measured.
[0053]
Here, a method for measuring the line width of the resist pattern 101 from the intensity profile created by the image processing computer 7 will be described.
[0054]
In order to measure the line width of the resist pattern 101 from the intensity profile created by the image processing computer 7, first, the valley portion of this intensity profile is fitted with a quadratic function. Then, the extreme value of this quadratic function is detected as a peak of the valley portion. Thereby, the peak position of the valley corresponding to the pattern edge of the resist pattern 101 can be obtained with high accuracy equal to or less than the pixel size of the image pickup element 6.
[0055]
Next, the distance between the peaks of two adjacent valleys is measured. The distance between the peaks of the two valleys corresponds to the line width of the resist pattern 101. The distance between the peaks of the two valleys obtained here (observed value of the line width of the resist pattern 101) is different from the actual value (absolute value) of the line width of the resist pattern 101. Since it has a linear relationship, if the ratio of the observed value to the absolute value of the line width of the resist pattern 101 is obtained in advance using a scanning electron microscope (SEM) or the like, it was measured from the intensity profile. By correcting the observed value of the line width of the resist pattern 101, the absolute value can be obtained.
[0056]
As described above, if the line width of the resist pattern 101 is obtained from the intensity profile created by the image processing computer 7, the line width of the resist pattern 101 can be accurately measured on the order of nanometers. Further, when a variation occurs in the line width of the resist pattern 101, the variation in the line width can be detected with high accuracy.
[0057]
As described above in detail, in the inspection apparatus 1 to which the present invention is applied, the control unit 8 performs illumination according to the integrated irradiation light amount of the illumination light calculated by the integration circuit 9 based on the light received by the light amount monitor 5. The opening / closing of the shutter 4 provided in the optical system is controlled to adjust the amount of illumination light applied to the resist pattern 101 to be inspected. Therefore, according to this inspection apparatus 1, the irradiation light quantity of the illumination light is adjusted to, for example, an irradiation threshold value that causes the resist pattern 101 to shrink, and the resist pattern 101 does not shrink without causing the resist pattern 101 to shrink. The width etc. can be inspected appropriately.
[0058]
The inspection apparatus 1 described above is an example of an inspection apparatus to which the present invention is applied, and the present invention is not limited to the configuration of the inspection apparatus 1. For example, in the inspection apparatus 1 described above, the shutter 4 is disposed in front of the polarization beam splitter 18 in the illumination optical system. However, the shutter 4 is disposed in the subsequent stage of the polarization beam splitter 18 and the polarization beam is provided. The irradiation light quantity of the illumination light applied to the inspection object may be adjusted by switching transmission / cut-off of the light that is polarized and separated by the splitter 18 and directed toward the inspection object.
[0059]
In the inspection apparatus 1 described above, the image of the inspection object illuminated by the illumination light is imaged by the image pickup element 6 and the state of the inspection object is inspected based on this image. You may make it test | inspect the inspection object illuminated with light visually, and may test | inspect the state.
[0060]
In the above, the example in which the state of the resist pattern 101 formed on the semiconductor wafer 100 is inspected in the lithography process of the semiconductor process using the inspection apparatus 1 has been described. However, the present invention is not limited to the above example. However, the present invention is not limited to this, and can be effectively applied to inspection of an inspection target that may be damaged by irradiation of illumination light. For example, when inspecting a living tissue that may cause tissue destruction or cell necrosis when the illumination light irradiation amount is excessive, or when the illumination light irradiation amount is excessive, it may be exposed to light. The present invention is very effective when a certain photosensitive material is inspected and inspected.
[0061]
【The invention's effect】
As described above in detail, according to the present invention, the amount of illumination light irradiated to the inspection object can be adjusted to an appropriate value according to the inspection object, so that the inspection object is not damaged. The inspection of the inspection object can be performed appropriately.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an example of an inspection apparatus to which the present invention is applied.
FIG. 2 is a schematic view showing a state in which a semiconductor wafer on which a resist pattern to be inspected is formed is placed on a movable table of the inspection apparatus.
FIG. 3 is a view showing an image of a resist pattern imaged by an image imaging element of the inspection apparatus.
FIG. 4 is a diagram showing an intensity profile created by an image processing computer based on an image of a resist pattern imaged by the image imaging device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inspection apparatus, 2 Movable table, 3 Light source, 4 Shutter, 5 Light quantity monitor, 6 Image pick-up element, 7 Image processing computer, 8 Control part, 9 Integration circuit, 18 Polarization beam splitter, 19 1/4 wavelength plate, 20 Objective lens, 23 capacitive sensor, 100 semiconductor wafer, 101 resist pattern

Claims (11)

An inspection apparatus that inspects the inspection object illuminated by the illumination light and inspects the state of the inspection object,
A light source that emits illumination light for illuminating the inspection object;
An illumination optical system for guiding the illumination light emitted from the light source to the inspection object;
A light amount monitoring means for monitoring the irradiation light amount of the illumination light irradiated to the inspection object,
The illumination optical system is provided with shutter means for transmitting or blocking the illumination light emitted from the light source, and the shutter means is controlled according to the illumination light amount monitored by the light amount monitor means. By this, the inspection apparatus characterized by adjusting the irradiation light quantity of the illumination light irradiated to the said test object. Image capturing means for capturing an image of the inspection object illuminated by illumination light;
An imaging optical system for forming an image of the inspection object on the image pickup means;
Image processing means for processing the image to be inspected imaged by the image imaging means,
The inspection apparatus according to claim 1, wherein the state of the inspection object is inspected by processing and analyzing the image of the inspection object by the image processing means. The inspection apparatus according to claim 1, further comprising a focus control unit that adjusts a focus state of the illumination light. 4. The inspection apparatus according to claim 3, wherein the focus control unit includes a capacitance type sensor, and adjusts the focus state of the illumination light based on information detected by the capacitance type sensor. . 2. The inspection apparatus according to claim 1, further comprising an ultraviolet solid-state laser device that emits ultraviolet laser light having a wavelength of 355 nm or less as the light source. The inspection apparatus according to claim 1, further comprising an acousto-optic element as the shutter unit. 6. The inspection apparatus according to claim 5, further comprising a CCD camera having high sensitivity to ultraviolet laser light having a wavelength of 355 nm or less as the light quantity monitoring means. A polarization beam splitter is provided in the illumination optical system, the polarization beam splitter splitting the illumination light emitted from the light source into light that is directed toward the inspection object and light that is directed toward the light amount monitoring means. The inspection apparatus according to claim 1. 9. The inspection apparatus according to claim 8, wherein the illumination optical system is provided with a quarter-wave plate that converts light polarized by the polarizing beam splitter and directed to the inspection object into circular deflection. . The inspection object is a resist pattern formed on a semiconductor wafer,
By controlling the shutter unit according to the irradiation light amount of the illumination light monitored by the light amount monitoring unit, the irradiation light amount of the illumination light irradiated to the resist pattern is equal to or less than an irradiation threshold value that causes the resist pattern to contract. The inspection apparatus according to claim 1, wherein the inspection apparatus is adjusted. When the illumination light emitted from the light source is guided to the inspection object by the illumination optical system to illuminate the inspection object, and when the inspection object illuminated by the illumination light is observed to inspect the state of the inspection object,
While monitoring the amount of illumination light irradiated to the inspection object using a light amount monitor means,
Shutter means for transmitting or blocking illumination light emitted from the light source is disposed in the illumination optical system, and the shutter means is controlled according to the amount of illumination light monitored by the light quantity monitor means. The inspection method characterized by adjusting the irradiation light quantity of the illumination light irradiated to the inspection object.

Images