KR20220136419A - Light filtering device, optical microscope and defect observation apparatus - Google Patents

Abstract

The present invention is a light filtering device including a shutter 212 having an axial part and having a structure that can be opened and closed, and a substrate 201 having a shutter opening 264, wherein a voltage is applied between the shutter 212 and the substrate 201. It has a configuration to apply, the shutter 212 has a configuration in which it is in an open state by rotating around the shaft portion and moving to the shutter opening 264, and the opening angle 280 of the shutter is adjusted to be less than 90 degrees. have Thereby, fatigue failure of the shutter of the light filtering device used for the optical microscope which is a component of a defect observation apparatus can be prevented, and the lifetime of a shutter array device can be lengthened.

Description

Light filtering device, optical microscope and defect observation apparatus

The present invention relates to a light filtering device, an optical microscope, and a defect observation apparatus.

The defect observation apparatus is a scanning electron microscope (SEM), etc. that review, classify, etc., various defects, foreign substances, etc. (hereinafter referred to as "defects, etc.") occurring on the surface of a wafer which is a substrate of a semiconductor in a semiconductor manufacturing line, etc. are being prepared

It is preferable that the defect observation apparatus is further equipped with an optical microscope. The defect observation apparatus has a function of controlling an optical microscope, efficiently and automatically detecting a defect or the like on the wafer surface, and performing coordinate alignment. About the minute defect etc. which were detected with the optical microscope, the shape can be observed in detail by controlling SEM, and a component analysis can be carried out. It is preferable that the optical microscope can be used as a dark field optical microscope (DFOM:Dark Field Optical Microscope).

Moreover, a defect observation apparatus has a function of automatically outputting classification data, such as an SEM image, a defect, element analysis data, etc., and can also produce a defect map from the output data. Moreover, a defect observation apparatus can also perform observation, classification, and analysis of a defect etc. based on the produced defect map. For this reason, the defect observation apparatus is also called review SEM. It is also called a defect review-SEM (SEM) or a wafer inspection SEM.

In other words, in a defect observation apparatus, an optical microscope and an SEM have a common stage, and the wafer mounted on this stage is observed with an optical microscope, the position of a detected defect etc. is specified, and the defect etc. are SEM. can be observed by For example, according to a defect map with a precision of several tens of μm, a defect, etc. can be searched for in a range of several hundred nm using a dark-field microscope of a defect observation device, and the position of a defect, etc. can be specified with an accuracy of several μm or less. have.

Thereby, the deviation of the coordinate system of an optical microscope and SEM can be corrected, the success rate of defect observation can be improved, and high throughput can be maintained. Moreover, in the manufacturing process of a semiconductor device, the defect etc. which cause defects, such as insulation defect and a short circuit of wiring, can be detected early, the source of the defect, etc. can be revealed, and a yield fall can be prevented.

In patent document 1, in the defect observation apparatus provided with the 1st imaging part (optical microscope) and the 2nd imaging part (SEM), among the some imaging means of a 1st imaging part, the next imaging means or 2nd of a 1st imaging part The imaging condition of the imaging unit is set, and the number of integrated frames, acceleration voltage, probe current, imaging magnification, or imaging field is set as imaging conditions of the second imaging unit, and the position information of the defect detected by the first imaging unit and the first It is disclosed that a coordinate correction formula is computed based on the information obtained by image acquisition by an imaging part, and a defect is imaged using a 2nd imaging part based on the corrected positional information.

In Patent Document 2, a shutter having holes arranged in a two-dimensional shape on an SOI wafer, an optically opaque thin film covering the holes, a shutter pattern arranged in a two-dimensional shape on the SOI wafer, and a working electrode formed on the SOI wafer. An optical filtering device having an array is disclosed. Here, SOI is an abbreviation of Silicon on Insulator, and the SOI wafer has a structure in which an oxide insulating film (BOX layer: Buried Oxide layer) and a surface Si film (SOI portion) are formed on a Si substrate.

Japanese Patent Laid-Open No. 2019-132637 Japanese Patent No. 5867736

In a dark field microscope, a pupil filter according to the type of defect etc. is required, and the micro shutter which has a dimension of 1 mm or less corresponding to various types of defects etc. is calculated|required. It is thought that various spatial filters can be formed by opening and closing such a shutter.

In defect detection by a conventional dark-field optical system that does not use such a shutter, the spatial characteristics and polarization characteristics of the pupil plane of various defect scattered light are used to determine the possibility of discriminating between a defect and the wafer roughness, which is the detection noise. It was raised by a spatial filter and a polarizing filter.

Since the shape of the spatial filter advantageous for detection differs depending on the type of defect etc., in order to improve the detection sensitivity of multiple types of defects, multiple types of spatial filters and a filter switching mechanism are needed. It is because the opening/closing location of a shutter can be selected by using a filter switching mechanism, and multiple types of spatial filters can be comprised.

During the opening/closing operation of the shutter, the amount of deformation generated in the suspension portion, which is an elastically deformable shaft portion, increases. For this reason, it becomes easy to generate|occur|produce the fatigue fracture in the axial part of a shutter and its peripheral part by repetition of opening/closing operation, and there is concern that the lifetime of a shutter becomes short.

An object of the present invention is to prevent fatigue breakdown of a shutter of a shutter array device (light filtering device) used for an optical microscope, which is a component of a defect observation apparatus, and to prolong the life of the shutter array device.

A light filtering device of the present invention includes a shutter having a shaft portion and having a configuration that can be opened and closed, and a substrate having a shutter opening, and has a configuration for applying a voltage between the shutter and the substrate, wherein the shutter rotates around the shaft portion and It has a structure used as an open state by moving to a shutter opening part, and has a structure in which the opening angle of a shutter is adjusted to less than 90 degrees.

ADVANTAGE OF THE INVENTION According to this invention, fatigue failure of the shutter of the optical filtering device used for the optical microscope which is a component of a defect observation apparatus can be prevented, and the lifetime of a shutter array device can be prolonged.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows the defect observation apparatus which concerns on embodiment.
FIG. 2 : is a schematic block diagram which shows the optical microscope which is a defect detection part of the defect observation apparatus of FIG.
3A is a schematic enlarged view showing a shutter array device and a microlens array.
Fig. 3B is a schematic enlarged view showing a state in which shutters constituting the shutter array device of Fig. 3A are closed except for a part.
Fig. 3C is a schematic enlarged view showing a state in which the shutters constituting the shutter array device of Fig. 3A are all closed.
Fig. 3D is a diagram showing a spatial filter corresponding to the state of the shutter array device of Fig. 3A;
Fig. 3E is a diagram showing a spatial filter corresponding to the state of the shutter array device of Fig. 3B.
Fig. 3F is a diagram showing a spatial filter corresponding to the state of the shutter array device of Fig. 3C.
Fig. 4A is a perspective view showing the shutter array device of the first embodiment.
Fig. 4B is a perspective view showing one shutter array.
4C is a perspective view showing one electrode array.
Fig. 5 is a cross-sectional view taken along line BB of Fig. 4A.
Fig. 6 is a cross-sectional view taken along line AA of Fig. 4A.
Fig. 7 is a top view of the rack of Fig. 4A.
Fig. 8 is a cross-sectional view showing the shutter array device of the second embodiment.
Fig. 9 is a cross-sectional view showing a shutter array device according to a third embodiment.
10A is a cross-sectional view showing a shutter array of a comparative example.
Fig. 10B is a cross-sectional view showing a shutter array according to the fourth embodiment.
Fig. 10C is a top view showing a shutter array according to the fourth embodiment.
Fig. 11 is a cross-sectional view showing a shutter array according to a fifth embodiment.
Fig. 12A is a cross-sectional view showing a shutter array according to a sixth embodiment.
Fig. 12B is a cross-sectional view showing a state in which the shutter array according to the sixth embodiment is installed on a rack.
Fig. 13 is a top view showing the details of the shutter array in Example 7;
Fig. 14 is a top view showing the details of the shutter array according to the eighth embodiment.
15 is a schematic cross-sectional view showing a shutter array according to an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows a defect observation apparatus.

In this figure, the defect observation apparatus 10 includes a scanning electron microscope 1002 (SEM), an optical microscope 1003 (defect detection unit), a control unit 1006 , a terminal 1007 , and a recording apparatus. 1008 and a network 1009 are provided.

The scanning electron microscope 1002 is installed in the vacuum chamber 1005 together with the stage 1004. A wafer 1001 is mounted on the stage 1004 . The wafer 1001 can be moved together with the stage 1004 movable with respect to the X and Y axes. Thereby, observation with the scanning electron microscope 1002 and the optical microscope 1003 is possible with respect to the arbitrary surface of the wafer 1001.

The optical microscope 1003 includes a laser light source 1010 , an objective lens 1013 , an imaging lens 1015 , and an imaging element 1016 . The objective lens 1013 is provided in the vacuum chamber 1005 . For this reason, the vacuum sealing window 1014 is provided so that light passing through the objective lens 1013 reaches the image pickup device 1016 . Between the vacuum sealing window 1014 and the imaging lens 1015, in order from the vacuum sealing window 1014 side, a microlens array 1103, a shutter array device 1101, and a microlens array 1102 are provided. . The light beam irradiated from the laser light source 1010 passes through the vacuum sealing window 1011 and is configured to be irradiated onto the upper surface of the wafer 1001 through the mirror 1012 .

Light reflected from the upper surface of the wafer 1001 passes through the objective lens 1013 and the vacuum sealing window 1014 in order, and the microlens array 1103, the shutter array device 1101, and the microlens array 1102. is passed through sequentially, is imaged by the imaging lens 1015 , and is detected by the imaging device 1016 . As the imaging element 1016, a two-dimensional CCD sensor, a line CCD sensor, a TDI sensor group in which a plurality of TDIs are arranged in parallel, a photodiode array, or the like are used. Here, CCD is an abbreviation for Charge-Coupled Device. In addition, TDI is an abbreviation for Time Delay Integration.

The scanning electron microscope 1002 and the optical microscope 1003 are fixed so as to maintain an accurate distance.

The control unit 1006 includes a stage control circuit 1018, an SEM imaging system control circuit 1019, an image processing circuit 1020, an external input/output interface 1021, a central arithmetic unit 1022 (CPU), It has a memory 1023 . The stage control circuit 1018 , the SEM imaging system control circuit 1019 , and the image processing circuit 1020 are connected to the external input/output interface 1021 , the central arithmetic unit 1022 , and the memory 1023 via a bus 1024 . has been The stage control circuit 1018 , the SEM imaging system control circuit 1019 , and the image processing circuit 1020 are circuits for moving the wafer 1001 , observing surface defects of the wafer 1001 , and other operations. The image processing circuit 1020 integrates the signals of the image acquired by the imaging element 1016, performs data conversion, etc., to determine the type of a defect or the like, and to specify the position and size thereof. Information regarding the result of determination, identification, etc. will be referred to as "defect information" in this specification.

The defect information is input to the recording device 1008 or the memory 1023 . The memory 1023 is mainly used for temporary storage. On the other hand, the recording apparatus 1008 can be used to accumulate and store the acquired defect information.

In the control unit 1006 , the stage control circuit 1018 controls the stage 1004 and the SEM imaging system control circuit 1019 controls the scanning electron microscope 1002 based on the defect information. Then, in the control unit 1006, some or all of the defects detected by the optical microscope 1003 are observed in detail, and the defects and the like are classified and the cause of their occurrence is analyzed. Further, in the control unit 1006, control of the focus and output of the SEM image, control of analysis, analysis of data obtained by the scanning electron microscope 1002, position correction of defects obtained by the optical microscope 1003, etc. are also performed. In addition, in the control unit 1006, display to the terminal 1007, data transmission via the network 1009, and the like can also be performed.

In the terminal 1007, conditions related to observation of defects and the like are set. In addition, in the terminal 1007, parameter setting for controlling the scanning electron microscope 1002, the optical microscope 1003, and the stage 1004 is performed. In addition, in the terminal 1007, the setting related to the opening/closing operation of the shutter (to be described later) of the shutter array device 1101 is also performed. In addition, in the terminal 1007, the angle (opening angle) when the shutter is opened can also be adjusted to an appropriate value. In this case, a method of adjusting the voltage applied to the shutter array device 1101 while checking the image converted into the pupil image from the image obtained by the imaging element 1016 with the terminal 1007 may be employed. Accordingly, it is possible to prevent failures such as adhesion to the substrate and damage to the shaft portion of the shutter caused by opening the shutter too much.

In the axial portion of the shutter, a force as an elastic body that tries to return to the closed state acts against the stress in the open state of the shutter. The opening angle is determined by the balance between this force and the electrostatic force that tries to open the shutter generated by the above voltage application. Accordingly, the opening angle can be adjusted by adjusting the above voltage. The upper limit of the opening angle of the shutter is determined by the above voltage.

2 : is a schematic block diagram which shows the optical microscope which is a defect detection part of a defect observation apparatus.

In this figure, the optical microscope 20 includes an imaging element 100 (sensor), an imaging lens 101 , and an objective lens 102 . Between the imaging lens 101 and the objective lens 102, microlens arrays 106 and 107 are provided. A shutter array device 200 (light filtering device) is provided between the microlens arrays 106 and 107 . The microlens arrays 106 and 107 and the shutter array device 200 are provided in the vicinity of the pupil surface of the optical microscope 20 .

The objective lens 102 is configured such that a light beam 300 irradiated from the laser light source 103 to the wafer 104 is reflected on the surface of the wafer 104 , and the reflected light 301 is incident thereon. The light passing through the objective lens 102 passes through the pupil surface (Fourier transform surface) and the imaging lens 101, reaches the image pickup device 100, and is detected as an electrical signal. In addition, the light beam 300 irradiated from the laser light source 103 passes through the vacuum sealing window 351 , is reflected by the mirror 352 , and is irradiated to the wafer 104 .

When the defect 108 is present in the wafer 104 , the light ray 300 striking the defect 108 is reflected, and a reflected light 301 different from normal is generated. This reflected light 301 is detected by the imaging device 100 , and data corresponding to the image of the defect 108 can be acquired by the image processing circuit 1020 of FIG. 1 . By moving the stage 105 , the defect 108 present on the surface of the wafer 104 can be found.

3A is a schematic enlarged view showing a shutter array device and a microlens array.

In this figure, the shutter array device 200 is provided between the microlens arrays 106 and 107 . The shutters 220 of the shutter array device 200 are all open. For this reason, the reflected light 302 passing through the shutter array device 200 converges in the shutter opening 304 , connects the focal points, and becomes the light 303 .

3B shows a state in which some shutters 220 other than the shutters 220 are closed. Also, FIG. 3C shows a state in which all shutters 210 are closed. In this way, the plurality of shutters 210 and 220 have a configuration that can be opened and closed independently, respectively.

3D, 3E and 3F show spatial filters corresponding to the states shown in Figs. 3A, 3B and 3C, respectively. 3D, 3E, and 3F are views viewed from above or below the shutter 220 .

In these drawings, the shutter closed state 211 is shown in black, and the shutter open state 221 is shown in white. A plurality of types of spatial filters (spatial masks) can be configured by individually controlling ON/OFF for each pixel of the shutter array device 200 . 3A, 3B, and 3C, the shutters 210 and 220 of the shutter array device 200 and the lenses of the microlens arrays 106 and 107 are arranged in three rows and three columns, but this is an example and necessary Accordingly, a large-scale matrix may be further formed.

EMBODIMENT OF THE INVENTION Hereinafter, an Example is demonstrated using drawings.

Example 1

Fig. 4A is a perspective view showing the shutter array device of the first embodiment.

The shutter array device 200 shown in this figure has the shutter array 205, the electrode array 206, and the rack 260 (pedestal). The shutter array 205 and the electrode array 206 have a substrate 201 and are fixed to a rack 260 . The shutter array 205 and the electrode array 206 each have a rectangular parallelepiped shape, and are provided on an inclined surface of the concave-convex structure provided on the rack 260 . In other words, the shutter array 205 and the electrode array 206 are provided on the inclined surface of the rack 260 . As a result, the shutter array 205 and the electrode array 206 are inclined with respect to the bottom surface of the rack 260 .

The substrate 201 is divided by a substrate division slit 202 .

The shutter array 205 and the electrode array 206 are adhesively fixed by a conductive adhesive on the adhesive surface 250 to ensure electrical conduction. The shutter array 205 and the electrode array 206 are respectively adhered and fixed to the rack wiring 261 provided on the rack 260 and the bonding surface 251 with a conductive adhesive to ensure electrical conduction. In addition, a conductive adhesive film, solder, etc. may be used instead of a conductive adhesive, and metal bonding using Au-Au, Cu-Cu, Cu-Sn, etc. may be used.

In this figure, shutters 212 (opening and closing plates) are arranged in a matrix shape of three rows and three columns, and three electrode arrays 206 are arranged on both sides of each of the three electrode arrays 206, but the present invention is not limited to this. , for example, a configuration in which the shutters 212 are arranged in a matrix of 30 rows and 30 columns together with the plurality of electrode arrays 206 may be employed. In summary, a plurality of shutters 212 are arranged adjacent to each other.

The shutter array 205 and the electrode array 206 have a rectangular parallelepiped shape with one dimension (each length, width, and height) of approximately 1 mm x 3 mm x 1 mm.

Fig. 4B shows one shutter array.

In this figure, the shutter array 205 includes one shutter support portion 203 in which three shutters 212 are arranged in a line, three substrates 201 , a shutter support portion 203 and a substrate 201 . It has an insulating layer 270 provided therebetween. Substrate division slits 202a and 202b are provided between adjacent substrates 201 . In other words, the substrate 201 is divided into substrate division slits 202a and 202b. The insulating layer 270 is integrated with the shutter support 203 . The shutter support 203 and the substrate 201 are insulated by the insulating layer 270 so that different voltages can be applied to each.

In this embodiment, the shutter 212, the shutter support portion 203, and the substrate 201 are formed of silicon (Si). On the other hand, the insulating layer 270 is formed of silica (SiO ₂ ).

4C shows one electrode array.

As shown in this figure, the electrode array 206 includes three electrode plates 207 without shutters and three substrates 201 . Substrate division slits 202a and 202b are provided between adjacent substrates 201 . In other words, the substrate 201 is divided into substrate division slits 202a and 202b. The electrode plate 207 is also divided into slits 204a and 204b. The electrode array 206 is not provided with an insulating layer. The substrate 201 and the electrode plate 207 are configured to be electrically connected. That is, the substrate 201 and the electrode plate 207 are divided into three by the substrate division slits 202a and 202b and the slits 204a and 204b so that different voltages can be applied to the three. have. Moreover, the adjacent board|substrates 201 are connected with the insulating adhesive agent. Thereby, the electrode plate 207 can be used as a terminal for connecting the board|substrate 201 and the outside.

As shown in FIG. 4A , a wire 240 is connected to the end of the shutter support part 203 . Further, a wire 241 is connected to the electrode plate 207 . The wires 240 and 241 are fixed by wire bonding or the like. Accordingly, for the opening and closing operation of the shutter 212 , the voltage may be set to ON or OFF and applied.

Fig. 5 shows a cross section B-B of Fig. 4A.

In FIG. 5 , the rack 260 is provided with a plurality of rack openings 263 perpendicular to the bottom surface of the rack 260 . Then, the shutter array 205 is provided so that the shutter opening 264 communicates with each of the rack openings 263 . The shutter opening 264 is provided perpendicularly to the upper surface of the shutter support 203 .

In this embodiment, the width of the rack opening 263 is 700 mu m. As for the width of the rack opening part 263, 100-1000 micrometers is preferable.

The shutter 212 is parallel to the upper surface of the shutter support 203 in the closed state (shutter closing 223 ). On the other hand, in the state in which the shutter 212 is opened (the shutter opening 213), the shutter angle 280 (opening angle) is smaller than 90 degrees.

A rack insulating layer 262 is provided on the upper surface of the rack 260 , and a rack wiring 261 is formed on the surface of the rack insulating layer 262 . The rack wiring 261 and the rack insulating layer 262 are also provided between the shutter array 205 and the rack 260 and between the electrode array 206 and the rack 260 . Electrical connection between the rack wiring 261 and the substrate 201 is made through the substrate bottom surface 232 and the substrate side surface 233 using a conductive adhesive. In other words, the rack 260 has the rack wiring 261 electrically connected to the board 201 .

This makes it possible to apply a voltage to each of the substrates 201 . In addition, since the rack insulating layer 262 is provided between the rack 260 and the rack wiring 261 , it is possible to prevent conduction between the adjacent rack wiring 261 .

As shown in this figure, in the state of the shutter opening 213, the lower end of the shutter 212 having an opening angle of less than 90 degrees and the substrate facing the upper surface of the shutter 212 (the surface on the right in the figure) ( The distance between the inner wall surfaces of the 201 is the smallest in the shutter opening 264 .

Further, since the substrate 201 of the shutter array 205 has an inclination, the shaft portion of the shutter 212 is pushed up above the rack opening 263 . In other words, the inner wall surface of the substrate 201 on the axial side of the shutter 212 partially covers the rack opening 263 . Then, the distance between the lower end of the upper surface of the shutter 212 and the lower end of the inner wall surface of the substrate 201 facing the upper surface of the shutter 212 (the shutter 212 and the inner wall surface of the substrate 201) is smaller than the width of the rack opening 263 and the shutter opening 264 . That is, the effective aperture ratio of the shutter array 205 is low. Here, the effective aperture ratio is defined as a ratio (percentage) calculated with the width of the shutter opening 264 as the denominator and the minimum distance as the numerator.

Therefore, the light passing through the rack opening 263 and the shutter opening 264 converges to less than the above minimum distance, and adjusts to connect the focus in the area where the width of the rack opening 263 or the shutter opening 264 is small. It is preferable to be The angle at which the light converges (angle in the longitudinal section of the reflected light 302 and the light 303 in Fig. 3A) is the inner wall surface of the substrate 201 and the shutter 212 of the reflected light 302 and the light 303. ), it is desirable to set it as an angle that does not collide with it.

Therefore, from the viewpoint of the effective aperture ratio, it is preferable that the inclination of the substrate 201 is small, that is, the inclination of the shutter opening 264 with respect to the rack opening 263 is small.

On the other hand, it is preferable to adjust so that the shutter angle 280 may become small from a viewpoint of the reduction of the stress in the axial part of the shutter 212.

From the above two viewpoints, the shutter angle 280 is preferably in a range from 85 degrees to 60 degrees, more preferably in a range from 80 degrees to 60 degrees, and particularly preferably in a range from 75 degrees to 60 degrees. do. Here, the meaning of the lower limit value "60 degrees" in the above range is a configuration in which the inclination of the substrate 201 is 0 degrees, that is, in a configuration in which the inner wall surfaces of the rack opening 263 and the shutter opening 264 are parallel to each other. In this case, it corresponds to a preferable that the effective aperture ratio is 50% or more. When the effective aperture ratio is less than 50%, the degree of convergence of light passing through the rack opening 263 and the shutter opening 264 becomes a problem, and it is not preferable from the viewpoint of increasing the interval between the adjacent shutter openings 264. not.

5, the shutter angle 280 is sufficient if the upper surface of the shutter 212 is parallel to the inner wall surface of the rack opening 263, and it is not necessary to make it larger than that. Accordingly, the shutter angle 280 may be the upper limit value obtained by subtracting the inclination of the substrate 201 from 90 degrees.

FIG. 6 is a cross-sectional view taken along line A-A of FIG. 4A .

In FIG. 6, the state of the shutter opening 213 and the shutter closing 223 is shown.

7 is a top view of the rack 260 of FIG. 4A.

In this figure, the rack wiring 261 is formed so as to include the inclined surface of the concave-convex structure provided on the rack 260 and electrically connect the upper edge of the rack opening 263 adjacent to the horizontal direction in the figure. Between the adjacent rack wiring 261, the insulating part 265 is provided in parallel to the rack wiring 261, and it is comprised so that it may not electrically conduct.

Example 2

Fig. 8 is a cross-sectional view showing the shutter array device of the second embodiment.

In the shutter array device 200 shown in this figure, the height of the board|substrate 201 is made lower than Example 1 shown in FIG. Other configurations are the same as in FIG. 5 .

Due to the structure in which the height of the substrate 201 is lowered, the length of the shutter opening 264 bent with respect to the rack opening 263 is shortened, and the opening area through which the optical axis passes in the shutter opening 213 is widened. can Moreover, even if the opening angle of the shutter 212 is made smaller, the opening area can be ensured.

In addition, by forming the rack wiring 261 to be an appropriate circuit, and connecting wiring such as a wire to the shutter supporting unit 203 in order to change the potential of the shutter supporting unit 203 and the shutter 212, the electrode array ( 206) can be omitted.

Example 3

Fig. 9 is a cross-sectional view showing a shutter array device according to a third embodiment.

In the shutter array device 200 shown in this figure, the height of the board|substrate 201 is made low similarly to Example 2 shown in FIG.

In this figure, it is arrange|positioned so that the edge part of the adjacent shutter arrays 205 may overlap. In other words, the substrate 201 of the shutter array 205 is arranged so as to partially cover the upper side of the shutter support 203 of the adjacent shutter array 205 . A gap 290 is provided in a portion where the substrate 201 and the shutter support 203 overlap. The electrode arrays 206 are similarly disposed so as to overlap. Since the gap 290 is provided, the board|substrate 201 and the shutter support part 203 below have a structure which does not contact. Thereby, insulation can be ensured and a short circuit can be prevented. In addition, instead of providing the gap 290, an insulating material may be inserted.

With the above configuration, the interval between the adjacent shutter openings 264 can be set to be narrow. As a result, the degree of integration of the shutter array 205 can be increased, and it becomes possible to increase the pattern of the spatial filter as well.

(Comparative example)

Fig. 10A shows a shutter array of a comparative example.

The shutter 212 shown in this figure is in an excessively open state and is in close contact with the inner wall surface 282 of the substrate 201 . In this case, the attached shutter 212 does not separate from the inner wall surface 282, and there is a fear that the opening/closing function may not be obtained.

Example 4

Fig. 10B shows the shutter array of the fourth embodiment.

In this figure, by providing the convex part 281 on the inner wall surface 282 of the board|substrate 201, the contact of the shutter 212 is made to become a part. Accordingly, it is possible to prevent the shutter 212 from being fixed in an open state. Moreover, the upper limit of the opening angle of the shutter 212 is set by the convex part 281.

5 and the like, a configuration in which the upper surface of the shutter array intersects the optical axis obliquely in the closed state of the shutter 212 is shown, but in the present invention, as shown in FIG. In the closed state at (212), it may be configured to intersect substantially perpendicular to the optical axis.

Fig. 10C is a view of the shutter array of the present embodiment as seen from the top.

The two convex parts 281 shown in this figure are provided in the vertical direction, and in the shutter opening 213, it supports the shutter 212 with a small area. As a result, the shutter 212 is opened too much due to an excessive voltage, and shock or vibration caused by troubles in the stage of the device, vibration or other abnormal situations caused by earthquakes, etc. occur, and the opening angle of the shutter 212 is within the set range. Even if it exceeds , it is possible to prevent the shutter 212 from being attached to the substrate 201 and not moving, and long-term reliability can be secured.

Example 5

Fig. 11 shows the shutter array of the fifth embodiment.

In this figure, a convex portion 283 is provided on a part of the lower surface of the shutter 212 . Thereby, when the shutter 212 is opened too much, it is prevented that the shutter 212 is attached to the board|substrate 201 and becomes stationary.

Example 6

Fig. 12A shows the shutter array of the sixth embodiment.

In this figure, the shutter opening part 264 of the board|substrate 201 is inclined with respect to the bottom surface of the shutter support part 203, and is formed.

Fig. 12B shows a state in which the shutter array of this embodiment is installed in a rack.

As shown in this figure, since the shutter opening 264 of the substrate 201 has an inclined shape, when the shutter array 205 is installed in the rack 260 at a predetermined angle, the rack opening ( The inner wall surface of the 263 is substantially parallel to the inner wall surface of the shutter opening 264 . In other words, the rack opening 263 and the shutter opening 264 communicate substantially in parallel. Thereby, the rack opening 263 and the shutter opening 264 can be arranged substantially parallel to the optical axis.

Thereby, it is possible to avoid having a structure such that the inner wall surface of the substrate 201 covers the rack opening 263 with respect to the optical axis, and the effective opening ratio of the shutter array 205 can be improved. Moreover, the opening angle of the shutter 212 can be made small.

In the present embodiment, since the inner wall surface of the shutter opening 264 and the inner wall surface of the shutter support 203 are not parallel, even in a state where the opening angle of the shutter 212 is maximized, the shutter 212 is 264), it can be considered that the convex portion 281 in Fig. 10B or the convex portion 283 in Fig. 11 is provided to prevent the adhesion reliably.

With the configuration of the present embodiment, the diameter of the spot focused on each shutter 212 by the microlens array can be increased, and the design margin of the microlens can be increased. Moreover, this also contributes to cost reduction of a microlens.

In addition, the shutter array of this embodiment can be formed by tilting the substrate 201 and setting it in the dry etching apparatus when the silicon of the substrate 201 is etched away using the dry etching apparatus.

Example 7

Fig. 13 is a top view showing the details of the shutter array according to the seventh embodiment.

In this figure, the shutter 2001 which opens and closes is supported via the torsion bar 284 (shaft part) by the shutter support part 2002 which comprises the same plane. The shutter 2001 is connected in the vicinity of the central portion of the torsion rod 284 . A slit 2003 is provided between the shutter 2001 and the shutter support unit 2002 . Further, a slit 2004 is provided between the shutter support 2002 and the torsion rod 284 .

The torsion bar 284 has a linear shape with a central axis and a square shape, a rectangular shape, a circular shape, an elliptical shape, and the like in cross section. Although a circular shape is mechanically preferable, a square shape or a rectangular shape is preferable from a viewpoint of manufacturing easiness.

When the shutter 2001 is opened, torsional stress is generated in the torsion rod 284 . When the electrostatic force accompanying the application of voltage acts, since the shutter 2001 is opened, torsional stress is generated. When the application of the voltage is stopped, the force of static electricity is lost, the shutter 2001 is closed, and the torsional stress is eliminated. In this way, the torsion rod 284 functions as a torsion rod spring (elastic body).

In summary, as shown in this figure, the shutter 2001 has the structure of the single door which uses the torsion bar 284 as an axial part.

When the opening angle of the shutter 2001 becomes 90 degrees, the torsional stress becomes the maximum. For this reason, in consideration of the torsion bar 284 and the fatigue failure of its periphery, it is preferable that the opening angle of the shutter 2001 is smaller than 90 degrees.

Example 8

Fig. 14 is a top view showing the details of the shutter array according to the eighth embodiment.

In this figure, the shutter 2001 which opens and closes is supported via the meander rod 285 (shaft part) by the shutter support part 2002 which comprises the same plane. A slit 2004 is provided between the shutter support 2002 and the meander rod 285 . The meander rod 285 has, for example, a sine wave shape or the like, and has a cross section of a square shape, a rectangular shape, a circular shape, an elliptical shape, and the like.

When the shutter 2001 is opened, stress is generated in the direction in which the bent portion of the meander rod 285 that intersects with the direction of the rotation axis of the shutter 2001 (the direction of the long side of the shaft) extends.

With this configuration, as compared with the case of using the torsion bar 284 in Fig. 13, local stress is reduced, and reliability as a shutter array can be improved.

Next, the driving method of the shutter will be described.

Fig. 15 schematically shows a cross section of the shutter array.

In this figure, a voltage is applied to the shutter 212 through the shutter support 203 so as to have a positive potential V1 and to the substrate 201 so as to have a negative potential V2. An electrostatic force is generated by the potential difference generated by this, and the shutter 212 is opened.

As shown in this figure, the lower surface of the shutter 212 is positively charged, and the inner wall surface 282 of the substrate 201 is negatively charged. As a result, the shutter 212 rotates around the shaft, resulting in shutter opening.

When the voltage application is stopped, the shutter is returned to the closed state by the restoring force of the shaft.

For example, when V1 is a positive potential of +10 to 100V and V2 is a negative potential of -10 to -100V, the applied voltage is 20 to 200V. However, it also changes depending on the size of the shutter 212, and the present invention is not limited to the above example.

Further, in the above-described embodiment, the shutter array device produced by assembling components such as shutter array, electrode array, and rack is shown, but the present invention is not limited to this embodiment, and shutter array, electrode array, A part corresponding to a rack is formed by combining the surface oxidation treatment of silicon used in the semiconductor manufacturing process, photolithography, etching, vapor deposition, ion implantation, etc. You can do it.

10: defect observation device
20: light microscope
100: image pickup device
101: imaging lens
102: objective lens
103: laser light source
104: wafer
106, 107, 1102: microlens array
108: defect
200, 1101: shutter array device
201: substrate
202, 202a, 202b: substrate division slit
203, 2002: shutter support
204a, 204b: slit
205: shutter array
206: electrode array
207: electrode plate
211: shutter closed state
212, 220, 2001: shutter
221: shutter open state
240, 241: wire
250, 251: adhesive side
260: rack
261: rack wiring
263: rack opening
264: shutter opening
265: insulation
270: insulating layer
281, 283: convex part
282: inner wall surface
284: torsion rod
285: meander rod
290: gap
303: light
304: shutter opening
300: light
301, 302: reflected light
351: vacuum sealing window
352: mirror
1001: wafer
1002: scanning electron microscope
1003: light microscope
1004: stage
1005: vacuum bath
1006: control unit
1007: terminal
1008: recording device
1009: network
1010: laser light source
1013: objective lens
1015: imaging lens
1016: image pickup device
1018: stage control circuit
1019: SEM imaging system control circuit
1020: image processing circuit
1021: external input/output interface
1022: central arithmetic unit
1023: memory
2003, 2004: Slit.

Claims (18)

A shutter having a shaft and having a structure that can be opened and closed;
A substrate having a shutter opening,
It has a configuration for applying a voltage between the shutter and the substrate,
The shutter is configured to be in an open state by rotating around the shaft and moving to the shutter opening,
and an opening angle of the shutter is adjusted to be less than 90 degrees. The light filtering device according to claim 1, wherein the shutter has a configuration substantially perpendicular to the optical axis in the closed state. The light filtering device according to claim 1, wherein the shutter has a configuration that obliquely intersects an optical axis in a closed state. The light filtering device according to claim 1, wherein a plurality of the shutters are arranged adjacent to each other. The light filtering device according to claim 4, wherein each of the plurality of shutters has a configuration that can be opened and closed independently. The light filtering device according to claim 1, wherein the opening angle of the shutter is adjusted in a range from 85 degrees to 60 degrees. The method of claim 1, further comprising: a shutter array including the shutter, the shutter support and the substrate;
Comprising a rack for installing the shutter array,
The rack has a rack wiring that electrically connects with the substrate. The method of claim 7, wherein the rack is provided with a rack opening,
The shutter array is installed on an inclined surface of the rack,
and the shutter opening and the rack opening are in communication with each other. The light filtering device according to claim 8, wherein the shutter opening is curved with respect to the rack opening. The light filtering device according to claim 8, wherein the shutter opening and the rack opening communicate substantially in parallel. The light filtering device of claim 8 , wherein the adjacent shutter arrays are arranged to partially overlap. The light filtering device according to claim 1, wherein a convex portion is provided on the inner wall surface of the substrate or the shutter, and the upper limit of the opening angle is set by the convex portion. The light filtering device according to claim 1, wherein the upper limit of the opening angle of the shutter is determined by the voltage. The light filtering device according to claim 1, wherein the shaft portion is constituted by a torsion rod or a meander rod. The light filtering device according to claim 7, wherein an insulating layer is provided between the shutter support and the substrate. 8. The method of claim 7, further comprising an electrode array,
The electrode array is a light filtering device installed in the rack. The light filtering device according to claim 1,
An optical microscope with a microlens array. The optical microscope according to claim 17,
A defect observation apparatus provided with a scanning electron microscope.

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