JP2020020710A - Inspection device - Google Patents

Abstract

To provide an inspection device capable of performing high speed inspection while suppressing substrate charging.SOLUTION: An inspection device 100 includes: an electron gun which is provided on the upward of a substrate 101 and irradiates the substrate 101 with electron beams; a detector which detects secondary electrons emitted from the substrate 101; a vacuum ultraviolet light source which is provided diagonally in the upward of the substrate 101 and irradiates vacuum ultraviolet light; and light collecting means for collecting the vacuum ultraviolet light and irradiating the substrate 101 with the collected vacuum ultraviolet light.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multi-beam electron lens barrel and an inspection device. For example, the present invention relates to a multi-beam electron column that irradiates a multi-beam with an electron beam and an inspection apparatus that acquires a secondary electron image of a pattern emitted by irradiating the multi-beam and inspects the pattern.

  2. Description of the Related Art In recent years, circuit line widths required for semiconductor devices have become increasingly smaller with the increase in integration and capacity of large-scale integrated circuits (LSIs). These semiconductor elements are formed by exposing and transferring a pattern onto a wafer using a reduction projection exposure apparatus called a stepper, using an original pattern on which a circuit pattern is formed (also referred to as a mask or a reticle; hereinafter, collectively referred to as a mask). It is manufactured by forming a circuit.

  In addition, for the production of LSIs that require a large production cost, improvement of the yield is indispensable. However, as represented by a 1 gigabit-class DRAM (random access memory), patterns constituting an LSI are on the order of submicrons to nanometers. In recent years, with the miniaturization of LSI pattern dimensions formed on semiconductor wafers, the dimensions that must be detected as pattern defects have become extremely small. Therefore, there is a need for an inspection apparatus for inspecting defects of an ultrafine pattern transferred onto a semiconductor wafer with higher accuracy. In addition, one of the major factors that lower the yield is a pattern defect of a mask used when exposing and transferring an ultrafine pattern on a semiconductor wafer by photolithography. Therefore, there is a need for a high-precision inspection apparatus for inspecting defects of a transfer mask used in LSI manufacturing.

  As an inspection method, an optical image obtained by imaging a pattern formed on a sample such as a wafer such as a semiconductor wafer or a mask such as a lithography mask using a magnifying optical system at a predetermined magnification, and design data, or on the sample. There is known a method of performing an inspection by comparing the same pattern with an optical image obtained by imaging the same pattern. For example, as an inspection method, a “die-to-die (die-to-die) inspection” that compares optical image data obtained by imaging the same pattern at different locations on the same mask, or drawing a pattern using CAD data with a designed pattern as a mask When drawing data (design pattern data) converted to a device input format for input by the drawing device is input to the inspection device, design image data (reference image) is generated based on the data, and the pattern and the image are captured. There is a “die-to-database (die-database) inspection” for comparing the measured optical data with an optical image. In the inspection method in such an inspection apparatus, the inspection target substrate is mounted on a stage (sample stage), and the stage is moved, so that the light beam scans over the sample, and the inspection is performed. The inspection target substrate is irradiated with a light beam by the light source and the illumination optical system. The light transmitted or reflected by the inspection target substrate is imaged on the sensor via the optical system. The image captured by the sensor is sent to a comparison circuit as measurement data. After the alignment of the images, the comparison circuit compares the measured data with the reference data according to an appropriate algorithm, and if they do not match, determines that there is a pattern defect.

  In the above-described inspection apparatus, an optical image is obtained by irradiating the inspection target substrate with laser light and capturing a transmission image or a reflection image thereof. On the other hand, the inspection target substrate is irradiated with a multi-beam composed of a plurality of electron beams in an array arrangement in which a plurality of beam arrays arranged at the same pitch on a straight line are emitted from the inspection target substrate. Inspection devices for detecting pattern electrons by detecting secondary electrons corresponding to the respective beams have also been developed. In an inspection apparatus using an electron beam including such a multi-beam, secondary electrons are detected by scanning each small area of the inspection target substrate.

  Here, in the inspection apparatus using the electron beam, the portion of the sample to be inspected irradiated with the electron beam and the periphery thereof are charged. Since the inspection cannot be performed continuously for the charged portion unless the charge is removed, there is a problem that the inspection cannot be performed at high speed.

  Patent Document 1 discloses a means for introducing or generating an ultraviolet ray having a wavelength belonging to a vacuum ultraviolet ray range absorbed by the atmosphere into a vacuum of the sample chamber, and a portion in which gas is irradiated with a charged particle beam of the sample in the sample chamber. When the charged particle beam is irradiated on the sample, the sample is irradiated with ultraviolet rays to the surface of the sample or a member near the sample, and the gas is irradiated with the charged particle beam on the sample by the gas introducing tube. A charged particle beam apparatus characterized by comprising: an ultraviolet irradiation means for neutralizing the charge generated on the sample by the irradiation of the charged particle beam by ionizing the gas. I have.

Japanese Patent No. 4796791

  It is an object of the present invention to provide an inspection apparatus capable of performing an inspection at a high speed while suppressing charging of a sample to be inspected.

  An inspection device according to one embodiment of the present invention is provided above an inspection sample and irradiates an electron beam to the inspection sample with an electron gun; a detector for detecting secondary electrons emitted from the inspection sample; A vacuum ultraviolet light source that is provided diagonally above the test sample and irradiates vacuum ultraviolet light, and a light condensing unit that condenses vacuum ultraviolet light and irradiates the test sample with light is provided.

  In the above-described inspection apparatus, it is preferable that the condensing unit includes a spherical mirror that reflects the vacuum ultraviolet light emitted from the vacuum ultraviolet light source, and a cylindrical mirror that reflects the vacuum ultraviolet light reflected by the spherical mirror.

  In the above-described inspection apparatus, it is preferable that the condensing means has a toroidal mirror that reflects the vacuum ultraviolet light emitted from the vacuum ultraviolet light source.

  In the above inspection apparatus, the vacuum ultraviolet light source is preferably a deuterium lamp or an excimer lamp.

  In the above inspection apparatus, it is preferable that the vacuum ultraviolet light source is an excimer lamp and the condensing means has a cylindrical lens that transmits vacuum ultraviolet light emitted from the vacuum ultraviolet light source.

  According to one embodiment of the present invention, it is possible to provide an inspection apparatus capable of performing high-speed inspection while suppressing charging of a sample to be inspected.

It is a lineblock diagram showing the composition of the inspection device in a 1st embodiment. FIG. 2 is a conceptual diagram illustrating a configuration of a formed aperture array substrate according to the first embodiment. FIG. 2 is a cross-sectional view illustrating a configuration of a blanking aperture array mechanism according to the first embodiment. It is a figure showing an example of the individual blanking mechanism in a 1st embodiment. FIG. 2 is a schematic diagram of a light collecting unit in the first embodiment. It is a schematic diagram of the light collecting means in the second embodiment. It is a schematic diagram of the light collecting means in the third embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment, as an example of a device for acquiring an image of a substrate, an inspection device that captures a secondary electron image by irradiating a substrate to be inspected with a multi-beam by an electron beam will be described.

(First embodiment)
The inspection apparatus according to the present embodiment includes an electron gun that is provided above a sample to be inspected and irradiates an electron beam on the sample to be inspected, a detector that detects secondary electrons emitted from the sample to be inspected, A vacuum ultraviolet light source for irradiating vacuum ultraviolet light, and a light condensing means for condensing vacuum ultraviolet light and irradiating the sample to be inspected.

  Further, the light condensing means of the present embodiment has a spherical mirror that reflects the vacuum ultraviolet light emitted from the vacuum ultraviolet light source, and a cylindrical mirror that reflects the vacuum ultraviolet light reflected by the spherical mirror.

  FIG. 1 is a configuration diagram illustrating a configuration of a pattern inspection apparatus according to the present embodiment. In FIG. 1, an inspection device 100 for inspecting a pattern formed on a substrate is an example of an image acquisition device. The inspection device 100 includes an image acquisition mechanism 150 and a control system circuit 160 (control unit). The image acquisition mechanism 150 includes the electron beam column 102 (multi-beam electron column), the inspection room 103, the detection circuit 106, the pattern memory 123, the driving mechanism 132, the driving mechanism 142, and the laser length measurement system 122. In the electron beam column 102, an electron gun 201, an illumination lens 202, a shaped aperture array substrate 203, a blanking aperture array mechanism 204, a reduction lens 205, a limited aperture substrate 206, an objective lens 207, a main deflector 208, and a sub deflector 209, a blanking deflector 212, a reduction lens 213, a beam separator 214, an electrode 220, a multi-detector 222, a projection lens 224, 226, a deflector 228, a wide-area detector 230, and alignment coils 232 and 234. I have.

  In the inspection room 103, an XY stage 105 movable at least on an XY plane is arranged. On the XY stage 105, a substrate 101 to be inspected is arranged. The substrate 101 includes an exposure mask substrate and a semiconductor substrate such as a silicon wafer. When the substrate 101 is a semiconductor substrate, a plurality of chip patterns (wafer dies) are formed on the semiconductor substrate. When the substrate 101 is an exposure mask substrate, a chip pattern is formed on the exposure mask substrate. A plurality of chip patterns (wafer dies) are formed on the semiconductor substrate by exposing and transferring the chip pattern formed on the exposure mask substrate a plurality of times onto the semiconductor substrate. Hereinafter, a case where the substrate 101 is a semiconductor substrate will be mainly described. The substrate 101 is disposed on the XY stage 105 with the pattern formation surface facing upward, for example. Further, on the XY stage 105, a mirror 216 that reflects a laser beam for laser measurement emitted from a laser measurement system 122 arranged outside the inspection room 103 is arranged. Further, on the XY stage 105, marks 217 and 218 having different mark patterns and a transmission mark 219 having a limited beam incident area are arranged. It is preferable that the surface heights of the marks 217 and 218 and the transmission mark 219 be adjusted to the height of the surface of the substrate 101. The substrate 101 is an example of a sample to be inspected.

  The multi-detector 222 and the wide-area detector 230 are connected to the detection circuit 106 outside the electron beam column 102. The detection circuit 106 is connected to the pattern memory 123. The inside of the electron beam column 102a and the inspection room 103 is evacuated by a vacuum pump (not shown), and a vacuum state is formed. Note that the multi-detector 222 and the wide-area detector 230 are examples of a detector.

  As the wide-area detector 230, for example, a semiconductor detector, a plastic scintillator having a surface coated with a film for preventing static electricity, and a photoelectron detector connected thereto, or a simple ammeter on a plate made of a conductor can be used. Connected ones can also be used. In this case, it is advantageous to use a material having a low secondary electron generation efficiency, such as carbon, for the surface from the viewpoint of the accuracy of the inflow current measurement.

  For example, a primary electron optical system includes the illumination lens 202, the formed aperture array substrate 203, the reduction lens 205, the reduction lens 213, the objective lens 207, the main deflector 208, and the sub deflector 209. However, the present invention is not limited to this, and other coils, lenses, deflectors, and the like may be included in the primary electron optical system. Further, for example, a secondary electron optical system is configured by the beam separator 214, the projection lenses 224 and 226, the deflector 228, and the alignment coils 232 and 234. However, the present invention is not limited to this, and other coils, lenses, deflectors, and the like may be included in the secondary electron optical system.

  In the control system circuit 160, a control computer 110 that controls the entire inspection apparatus 100 includes, via a bus 120, a position circuit 107, a comparison circuit 108, a reference image creation circuit 112, a stage control circuit 114, a lens control circuit 124, a blanking circuit Control circuit 126, deflection control circuit 128, retarding control circuit 129, carry-in / carry-out control circuit 130, detection circuit 134, vacuum ultraviolet light source control circuit 136, storage device 109 such as a magnetic disk device, monitor 117, memory 118, and printer 119 is connected.

  Further, the pattern memory 123 is connected to the comparison circuit 108. The XY stage 105 is driven by the driving mechanism 142 under the control of the stage control circuit 114. In the drive mechanism 142, for example, a drive system such as a three-axis (XY-θ) motor that drives in the X, Y, and θ directions is configured, and the XY stage 105 is movable. As these X motor, Y motor, and θ motor (not shown), for example, a step motor can be used. The XY stage 105 is movable in the horizontal direction and the rotation direction by motors of XYθ axes. The moving position of the XY stage 105 is measured by the laser length measuring system 122 and supplied to the position circuit 107. The laser measuring system 122 measures the position of the XY stage 105 based on the principle of laser interferometry by receiving the reflected light from the mirror 216.

  The electron gun 201 is provided above the substrate 101. A high-voltage power supply circuit (not shown) is connected to the electron gun 201, and an acceleration voltage from the high-voltage power supply circuit is applied between a filament (not shown) in the electron gun 201 and an extraction electrode (anode), and a predetermined extraction electrode (Wehnelt) is provided. Is applied and the cathode is heated at a predetermined temperature, the electrons emitted from the cathode are accelerated and emitted as an electron beam 200. As the illumination lens 202, the reduction lens 205, the reduction lens 213, the objective lens 207, and the projection lenses 224 and 226, for example, electromagnetic lenses are used, and both are controlled by the lens control circuit 124. The beam separator 214 is also controlled by the lens control circuit 124. The collective blanking deflector 212 and the deflector 228 each include at least a two-pole electrode group, and are controlled by a blanking control circuit 126. The main deflector 208 and the sub deflector 209 are each formed of an electrode group having at least four poles, and are controlled by the deflection control circuit 128. The electrode 220 is formed on a disk having a through hole formed in the center thereof, and is controlled together with the substrate 101 by a retarding control circuit 129.

  Further, a vacuum ultraviolet light source 72 is provided in the inspection room 103 obliquely above the substrate 101. The vacuum ultraviolet light 74 emitted from the vacuum ultraviolet light source 72 is condensed by the light condensing means 80 and is irradiated on the substrate 101. The vacuum ultraviolet light source 72 is connected to the vacuum ultraviolet light source control circuit 136, and can emit vacuum ultraviolet light in conjunction with the irradiation of the electron beam 200 from the electron gun 201 and the movement of the XY stage 105.

  Here, FIG. 1 illustrates a configuration necessary for describing the present embodiment. The inspection apparatus 100 may normally have other necessary components.

FIG. 2 is a conceptual diagram illustrating a configuration of the formed aperture array substrate according to the present embodiment. In FIG. 2, a two-dimensional horizontal (x direction) m ₁ row × vertical (y direction) n ₁ step (m ₁ , n ₁ is an integer of 2 or more) holes (openings) are formed in the formed aperture array substrate 203. ) 22 are formed at a predetermined arrangement pitch in the x and y directions. The example of FIG. 2 shows a case in which a 23 × 23 hole (opening) 22 is formed. Each hole 22 is formed of a rectangle having the same size and shape. Alternatively, they may be circular with the same outer diameter. When a part of the electron beam 200 passes through each of the plurality of holes 22, the multi-beam 20 is formed. Here, an example is shown in which the holes 22 are arranged in two or more rows in both the horizontal and vertical directions (x, y directions), but the present invention is not limited to this. For example, one of the horizontal and vertical (x, y directions) may be a plurality of rows and the other may be only one row. In addition, the arrangement of the holes 22 is not limited to the case where the horizontal and vertical are arranged in a lattice as shown in FIG. For example, the holes in the k-th row in the vertical direction (y direction) and the holes in the k + 1-th row may be arranged so as to be shifted by the dimension a in the horizontal direction (x direction). Similarly, the holes in the (k + 1) -th row in the vertical direction (y-direction) and the holes in the (k + 2) -th row may be arranged so as to be shifted by the dimension b in the horizontal direction (x-direction). Next, the operation of the image acquisition mechanism 150 in the inspection device 100 will be described.

  An electron beam 200 emitted from an electron gun 201 (emission source) illuminates the entire formed aperture array substrate 203 almost vertically by an illumination lens 202. As shown in FIG. 2, a plurality of rectangular holes 22 (openings) are formed in the formed aperture array substrate 203, and the electron beam 200 illuminates an area including all the plurality of holes 22. Each part of the electron beam 200 applied to the position of the plurality of holes 22 passes through the plurality of holes 22 of the formed aperture array substrate 203, thereby forming, for example, a plurality of rectangular electron beams (multi-beams) 20a to 20a. 20d (solid line in FIG. 1) is formed.

  The formed multi-beams 20 a to 20 d (primary electron beams) pass through a blanking aperture array mechanism 204, are reduced by a reduction lens 205, and travel toward a central hole formed in a limited aperture substrate 206. Here, when the entire multi-beams 20a to 20d are collectively deflected by the collective blanking deflector 212 disposed between the shaping aperture array substrate 203 (blanking aperture array mechanism 204) and the reduction lens 205. Is displaced from the center hole of the restriction aperture substrate 206 and is shielded by the restriction aperture substrate 206. On the other hand, the multi-beams 20a to 20d not deflected by the collective blanking deflector 212 pass through the center hole of the limiting aperture substrate 206 as shown in FIG. Blanking control is performed by ON / OFF of the collective blanking deflector 212, and collective control of ON / OFF of the beam is performed. In this way, the limiting aperture substrate 206 shields the multi-beams 20a to 20d deflected by the collective blanking deflector 212 so that the beam is turned off. Then, the inspection multi-beams 20a to 20d are formed by the beam group that has been formed from the time the beam is turned on to the time the beam is turned off and that has passed through the limited aperture substrate 206.

The multi-beams 20a to 20d that have passed through the limiting aperture substrate 206 are refracted toward the optical axis by the reduction lens 213 to form a crossover (CO). Then, after passing through the beam separator 214 arranged at the crossover position of the multi-beam 20, the beam advances to the objective lens 207. The multi-beams 20a to 20d that have passed through the beam separator 214 are focused on the surface of the substrate 101 by the objective lens 207, and form images of the multi-beams 20a to 20d (electron beams) on the substrate 101. At this time, the multi-beams 20a to 20d become a pattern image (beam diameter) having a desired reduction ratio, and the entire multi-beam 20 passing through the limiting aperture substrate 206 is collectively moved in the same direction by the main deflector 208 and the sub-deflector 209. Then, the light is deflected, passes through the central hole of the electrode 220, and is applied to each irradiation position on the substrate 101 of each beam. In this case, the main deflector 208 deflects the entire multi-beam 20 to the reference position of the mask die scanned by the multi-beam 20 at a time. When scanning is performed while continuously moving the XY stage 105, tracking deflection is performed so as to further follow the movement of the XY stage 105. Then, the entire multi-beam 20 is collectively deflected by the sub deflector 209 such that each beam scans the corresponding area. The multi-beams 20 irradiated at one time are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the plurality of holes 22 of the formed aperture array substrate 203 by the above-described desired reduction ratio (1 / a). As described above, the electron beam column 102 a irradiates the substrate 101 with m ₁ × n ₁ multi-beams 20 at _{one time} . A bundle of secondary electrons including reflected electrons (multi-secondary electron 300) corresponding to each beam of multi-beam 20 from substrate 101 due to irradiation of a desired position on substrate 101 with multi-beam 20 (FIG. (Dotted line 1) is emitted.

  Here, a voltage is applied between the electrode 220 and the substrate 101 by the retarding control circuit 129 so that the incident energy of the primary electron beam on the desired substrate can be obtained. The electrode 220 is set to the ground potential as in the electron beam column 102a, and the substrate 101 is set to a predetermined negative potential. Thus, the primary electron beam (multi-beam 20) accelerated with high energy under vacuum is decelerated immediately before entering the substrate 101, and the secondary electrons (multi-secondary) of low energy emitted from the substrate 101 are reduced. The electron 300) can be accelerated to the multi-detector 222 side.

  After passing through the through hole of the electrode 220, the multi-secondary electrons 300 emitted from the substrate 101 are refracted by the objective lens 207 toward the center of the multi-secondary electrons 300 and proceed to the beam separator 214.

  Here, the beam separator 214 (for example, a Wien filter) generates an electric field and a magnetic field in a direction orthogonal to a plane orthogonal to a direction (optical axis) in which the multi-beam 20 travels. The electric field exerts a force in the same direction regardless of the traveling direction of the electrons. In contrast, a magnetic field exerts a force according to Fleming's left-hand rule. Therefore, the direction of the force acting on the electrons can be changed depending on the direction of the electrons. The multi-beam 20 (primary electron beam) entering the beam separator 214 from above is canceled out by the electric field force and the magnetic field force, and the multi-beam 20 goes straight down. On the other hand, for the multi-secondary electrons 300 that enter the beam separator 214 from below, both the force by the electric field and the force by the magnetic field act in the same direction, and the multi-secondary electrons 300 are bent obliquely upward. .

  The multi-secondary electrons 300 bent obliquely upward are projected on the multi-detector 222 while being refracted by the projection lenses 224 and 226 in a state where the wide area detector 230 is not carried in the optical path. The multi-detector 222 detects the projected multi-secondary electrons 300. The multi-detector 222 has, for example, a diode-type two-dimensional sensor (not shown). Then, at the diode-type two-dimensional sensor position corresponding to each beam of the multi-beam 20, each secondary electron of the multi-secondary electrons 300 collides with the diode-type two-dimensional sensor to generate an electron. Image data is generated for each pixel described below. When the scanning operation is performed while the XY stage 105 is moving, the deflector 228 is operated so that the detection position of each secondary electron of the multi-secondary electrons 300 in the multi-detector 222 does not shift with the movement of the XY stage 105. , The multi-secondary electron 300 is deflected so as to follow the movement of the XY stage 105 (tracking control is performed).

  As described above, the inspection apparatus 100 includes the primary electron optical system that adjusts the trajectory (irradiation position, focus, etc.) of the multi-beam 20 (primary electron beam) and the multi-secondary electron 300 (secondary electron). A secondary electron optical system for adjusting the trajectory (irradiation position, focus, etc.) is arranged. However, when the primary electron optical system and the secondary electron optical system have not been adjusted (beam adjustment), the electron trajectory as described above cannot be normally obtained. Therefore, it is necessary to adjust the primary electron optical system and the secondary electron optical system.

  FIG. 3 is a cross-sectional view illustrating a configuration of a blanking aperture array mechanism according to the present embodiment. In the blanking aperture array mechanism 204, as shown in FIG. 3, a substrate 31 made of, for example, silicon is arranged on a support 33. For example, the central portion of the substrate 31 is shaved thinly from the back surface side and processed into a membrane region 30 (first region) having a thin film thickness h. The periphery surrounding the membrane region 30 is an outer peripheral region 32 (second region) having a large thickness H. It is preferable that the upper surface of the membrane region 30 and the upper surface of the outer peripheral region 32 are formed at the same height position or substantially at the same height position. The substrate 31 is held on a support 33 on the back surface of the outer peripheral region 32. The center of the support 33 is open, and the position of the membrane region 30 is located in the open region of the support 33.

  In the membrane region 30, through holes 25 (openings) for passing the respective beams of the multi-beam 20 are formed at positions corresponding to the respective holes 22 of the formed aperture array substrate 203 shown in FIG. In other words, in the membrane region 30 of the substrate 31, a plurality of passage holes 25 through which the respective beams of the multi-beam using the electron beam pass are formed in an array. Then, on the membrane region 30 of the substrate 31, a plurality of electrode pairs each having two electrodes are arranged at positions facing each other across the corresponding passage hole 25 among the plurality of passage holes 25. Specifically, as shown in FIG. 3, a pair of blanking deflection control electrode 24 and counter electrode 26 (blanker: Blanking deflectors). Further, on the substrate 31, a wiring (not shown) for applying a deflection voltage to the control electrode 24 for each through hole 25 is formed. ON / OFF of individual deflection voltage application to each control electrode 24 is controlled by a blanking control circuit 126. Further, the opposing electrode 26 for each beam is grounded.

  FIG. 4 is a diagram illustrating an example of the individual blanking mechanism of the present embodiment. In FIG. 4, an individual control circuit 41 for individually applying a deflection voltage to each control electrode 24 is formed in the blanking control circuit 126. In each individual control circuit 41, an amplifier 46 (an example of a switching circuit) is arranged. In the example of FIG. 4, a CMOS (Complementary MOS) inverter circuit is arranged as an example of the amplifier 46. The CMOS inverter circuit is connected to a positive potential (Vdd: blanking potential: first potential) (for example, 5 V) (first potential) and a ground potential (GND: second potential). An output line (OUT) of the CMOS inverter circuit is connected to the control electrode 24. On the other hand, a ground potential is applied to the counter electrode 26.

  Either an L (low) potential (for example, ground potential) lower than the threshold voltage or an H (high) potential (for example, 1.5 V) that is higher than the threshold voltage is input to the input (IN) of the CMOS inverter circuit. Is applied as a control signal. In the present embodiment, when the L potential is applied to the input (IN) of the CMOS inverter circuit, the output (OUT) of the CMOS inverter circuit becomes a positive potential (Vdd), and the electric field due to the potential difference from the ground potential of the counter electrode 26. To control the beam to be turned off by deflecting the corresponding beam 20 and blocking it by the limiting aperture substrate 206. On the other hand, in a state where the H potential is applied to the input (IN) of the CMOS inverter circuit (active state), the output (OUT) of the CMOS inverter circuit becomes the ground potential, and the potential difference from the ground potential of the counter electrode 26 disappears, and the corresponding beam is removed. Since the beam 20 is not deflected, the beam is controlled to be turned ON by passing through the restriction aperture substrate 206.

  The electron beam 20 passing through each passage hole is individually deflected by a voltage applied to the two control electrodes 24 and the counter electrode 26 that form a pair. Blanking control is performed by such deflection. Specifically, the set of the control electrode 24 and the counter electrode 26 individually blank-deflects the corresponding beams of the multi-beams by the potential switched by the CMOS inverter circuit serving as the corresponding switching circuit. As described above, the plurality of blankers perform blanking deflection of the corresponding beams among the multi-beams that have passed through the plurality of holes 22 (openings) of the formed aperture array substrate 203.

  As the individual blanking mechanism, the CMOS circuit described above in the blanking control circuit 126 may not be formed on the substrate. For example, a simple power supply circuit including a DC power supply and a relay circuit is arranged in the blanking control circuit 126 so that the blanking control circuit 126 applies a desired potential to each electrode of the blanking aperture array mechanism 204. May be controlled. Further, a drive circuit such as the above-described CMOS circuit can be directly formed on the individual blanking aperture array mechanism having the control electrodes 24 and 26 and the passage holes.

  The individual blanking control of each beam by the blanking aperture array mechanism 204 is used when adjusting the optical system of the inspection apparatus 100. During normal pattern inspection after optical system adjustment, control is performed so that all beams are turned on. During the normal pattern inspection, the beam ON / OFF of the multi-beam 20 is controlled collectively by the collective blanking deflector 212. Note that, by synchronizing the blankers of the blanking aperture array mechanism 204 and performing ON / OFF control of all the beams at the same timing, the same operation as that of the collective blanking deflector 212 can be performed. In such a case, the batch blanking deflector 212 may be omitted.

  FIG. 5 is a schematic diagram of the light collecting means 76 in the present embodiment. Note that only the substrate 101 and the XY stage 105 are shown as members at the peripheral portion of the light collecting means 76, and descriptions of the electrode 220, the objective lens 207, the main deflector 208, the sub deflector 209, and the like are omitted. I have.

  The vacuum ultraviolet light source 72 is provided diagonally above the substrate 101. The vacuum ultraviolet light source 72 is preferably an excimer lamp or a deuterium lamp that can easily irradiate relatively high quality vacuum ultraviolet light.

  The condensing means 76 has a spherical mirror 82 and a cylindrical mirror 84. The spherical mirror 82 is a mirror in which the concave surface 83 of the spherical mirror is formed as a spherical surface. The cylindrical mirror 84 is a mirror in which the cylindrical mirror concave surface 85 is formed by a cylindrical surface. In a cross section perpendicular to the virtual cylinder axis corresponding to the cylindrical surface of the cylindrical mirror concave surface 85, the cylindrical mirror 84 has a light collecting action. On the other hand, in the cross section including the above-described virtual column axis, the cylindrical mirror 84 does not have a light collecting action. Therefore, the arrangement of the cylindrical mirror 84 is determined by the relationship between the vacuum ultraviolet light source 72, the spherical mirror 82, and the substrate 101 so as to exert a light condensing action. Note that, instead of the spherical mirror 82, an aspheric mirror may be used.

  The vacuum ultraviolet light 74 emitted from the vacuum ultraviolet light source 72 is reflected by the concave surface 83 of the spherical mirror 82 of the spherical mirror 82. The vacuum ultraviolet light 74 reflected by the spherical mirror concave surface 83 is reflected by the cylindrical mirror concave surface 85 of the cylindrical mirror 84 and irradiates the surface of the substrate 101. In this way, the vacuum ultraviolet light 74 is condensed by the condensing means 76.

  The spherical mirror 82 is an aluminum-coated mirror in which the spherical mirror concave surface 83 is coated with aluminum, or a dielectric multilayer mirror in which the dielectric mirror is coated with a dielectric multilayer film. It is preferable because an action can be obtained.

  Since the cylindrical mirror 84 is an aluminum-coated mirror in which the cylindrical mirror concave surface 85 is coated with aluminum or a dielectric multilayer mirror coated with a dielectric multilayer film, the reflectance of vacuum ultraviolet light is improved and the light is highly concentrated. It is preferable because an action can be obtained.

  Next, the operation and effect of this embodiment will be described.

  When the portion irradiated with the electron beam is irradiated with the vacuum ultraviolet light 74, the substrate 101 can be neutralized. Here, since a vacuum ultraviolet light laser is not commercially available or is expensive, an excimer lamp or a deuterium lamp is generally used as the vacuum ultraviolet light source 72. However, when an excimer lamp or a deuterium lamp is used, the spread of light becomes large unlike the case where a laser is used. When the spread of the vacuum ultraviolet light 74 becomes large, the amount of the vacuum ultraviolet light 74 applied to the portion irradiated with the electron beam becomes small, so that there is a problem that it takes a long time to remove electricity. Further, when the spread of the vacuum ultraviolet light 74 becomes large, there is a problem that the spread vacuum ultraviolet light 74 damages a portion of the substrate 101 that does not require static elimination and a problem that noise due to photoelectrons is generated. Was.

  In order to perform static elimination in a short period of time and suppress damage to the substrate 101 at locations where static elimination is not required, the vacuum ultraviolet light 74 is condensed and only a specific location on the substrate 101 is irradiated with vacuum ultraviolet light. Is preferred. However, the spectrum width of vacuum ultraviolet light using an excimer lamp or a deuterium lamp as a light source is wide, for example, the half width of an excimer lamp is about 10 nm. For this reason, even if an attempt is made to condense vacuum ultraviolet light using an optical lens, there is a problem that only a specific wavelength can be condensed due to chromatic aberration. Furthermore, since the refractive index in the vacuum ultraviolet region changes greatly depending on the wavelength, there is a problem that a slight change in the wavelength greatly changes the focal length of the optical lens, making it difficult to converge light well.

  In addition, if vacuum ultraviolet light for charge removal is irradiated as a separate step from the inspection, it is possible to irradiate the vacuum ultraviolet light from above the substrate 101, but the inspection takes time. In order to inspect the substrate 101 at high speed, it is preferable that static elimination can be performed while irradiating the substrate 101 with an electron beam. Usually, the electron beam is applied to the substrate 101 from above the substrate 101 via an objective lens such as a magnetic lens. However, the distance between the objective lens and the substrate 101 is very short, for example, about 1 mm. Therefore, the vacuum ultraviolet light used for static elimination is irradiated from obliquely above the substrate 101 so as not to hit the objective lens or the like. However, even if the light is condensed, the shape of the vacuum ultraviolet light on the substrate 101 expands in an elliptical shape, and there is a problem that it is difficult to converge light well.

  The light condensing means of the present embodiment has a spherical mirror 82 that reflects the vacuum ultraviolet light 74 emitted from the vacuum ultraviolet light source 72, and a cylindrical mirror 84 that reflects the vacuum ultraviolet light 74 reflected by the spherical mirror 82. .

  By using a mirror, the above-described problem of chromatic aberration when an optical lens is used can be avoided. Then, the vacuum ultraviolet light 74 emitted from the vacuum ultraviolet light source 72 provided diagonally above the substrate 101 is reflected by the spherical mirror 82 and further reflected by the cylindrical mirror 84. Accordingly, the vacuum ultraviolet light 74 can be irradiated in a circular shape without spreading in an elliptical shape on the surface of the substrate 101. Accordingly, since it is possible to irradiate the vacuum ultraviolet light 74 only to a specific portion irradiated with the electron beam, it is possible to provide an inspection apparatus capable of performing an inspection at high speed while suppressing charging of the substrate 101. Becomes possible.

  In addition, since the spherical mirror 82 and the cylindrical mirror 84 are relatively easy to manufacture, it is possible to easily improve the accuracy of light collection.

  Further, the inspection apparatus of the present embodiment does not attempt to suppress charging of the substrate 101 by introducing a gas that absorbs vacuum ultraviolet light to the surface of the substrate 101 and ionizing the gas into positive ions and negative ions. . Since no gas is introduced, the irradiation of the electron beam and the generation of secondary electrons are not blocked by the gas, so that the inspection can be performed with high accuracy.

  Further, in the inspection apparatus of the present embodiment, it is not necessary to provide a hole in the optical mirror and pass an electron beam through the hole. Therefore, the present invention can be easily applied to an inspection apparatus using the multi-beam 20.

  According to the inspection device of the present embodiment, it is possible to provide an inspection device capable of performing a high-speed inspection while suppressing charging of the substrate 101.

(Second embodiment)
The present embodiment differs from the first embodiment in that the condensing means has a toroidal mirror that reflects the vacuum ultraviolet light emitted from the vacuum ultraviolet light source. Here, description of the same points as in the first embodiment will be omitted.

  FIG. 6 is a schematic diagram of the light collecting means 77 in the present embodiment.

  The toroidal mirror 90 is a mirror having a toroidal mirror concave surface 91 having different curvatures in two orthogonal axes. The toroidal mirror concave surface 91 has, for example, a tall or tire shape having a virtual rotation axis center. The vacuum ultraviolet light 74 emitted from the vacuum ultraviolet light source 72 is reflected by the concave surface 91 of the toroidal mirror and is applied to the surface of the substrate 101. In this way, the vacuum ultraviolet light 74 is condensed by the condensing means 77.

  The toroidal mirror 90 is an aluminum-coated mirror in which the concave surface 91 of the toroidal mirror is coated with aluminum, or a dielectric multilayer mirror coated with a dielectric multilayer film. It is preferable because a light collecting action can be obtained.

  According to the inspection apparatus of the present embodiment, it is also possible to provide an inspection apparatus capable of performing an inspection at high speed while suppressing charging of the substrate 101.

(Third embodiment)
In the present embodiment, the vacuum ultraviolet light source is an excimer lamp, and the light collecting means differs from the first embodiment in that it has a cylindrical lens that transmits the vacuum ultraviolet light emitted from the vacuum ultraviolet light source. . Here, description of the same points as in the first and second embodiments will be omitted.

  FIG. 7 is a schematic diagram of the light collecting means 78 in the present embodiment.

  The spectrum width of the vacuum ultraviolet light 74 irradiated by the excimer lamp is relatively narrow. Thus, by using an excimer lamp as the vacuum ultraviolet light source 72, the vacuum ultraviolet light 74 emitted from the excimer lamp is condensed by a cylindrical lens and irradiated on the surface of the substrate 101, thereby suppressing the charging of the substrate 101 at a high speed. An inspection device capable of performing an inspection can be provided.

  The cylindrical lens is a lens having a cylindrical convex surface. The cross section of the cylindrical surface perpendicular to the cylinder axis has the shape of a plano-convex lens having a lens effect, and the cross section including the cylindrical axis of the cylindrical surface has the shape of a parallel flat plate having no lens effect. Note that, in the case of a plano-convex cylindrical lens having a cambered shape, the surface on the side opposite to the convex surface is, for example, a flat surface. However, the cylindrical lens used in the present embodiment is not limited to a plano-convex cylindrical lens.

  In the light condensing unit 78 shown in FIG. 7, a first cylindrical lens 92 and a second cylindrical lens 95 are provided as cylindrical lenses. The first cylindrical lens 92 has a first convex surface 93 which is a cylindrical surface, and a first plane 94 provided on the opposite side of the first convex surface 93. The second cylindrical lens 95 has a second convex surface 96 which is a cylindrical surface, and a second flat surface 97 provided on the opposite side of the second convex surface 96.

  Vacuum ultraviolet light 74 emitted from an excimer lamp, which is a vacuum ultraviolet light source 72, enters the first cylindrical lens 92 from the first convex surface 93 and exits from the first plane lens 94 to the outside of the first cylindrical lens 92. Next, the vacuum ultraviolet light 74 is incident on the second cylindrical lens 95 from the second convex surface 96, goes out of the second cylindrical lens 95 from the second plane 97, and is irradiated on the surface of the substrate 101.

  Here, the first cylindrical lens 92 and the second cylindrical lens 95 are arranged such that the first generatrix 93a of the first convex surface 93 and the second generatrix 96a of the second convex surface 96 intersect perpendicularly. ing. In FIG. 7, the first generatrix 93a is arranged perpendicular to the plane of the paper, and the second generatrix 96a indicated by a dashed line is arranged parallel to the plane of the paper. Thereby, the light condensing action can be strengthened. Note that the first bus 93a and the second bus 96a are both virtual, and the first bus 93a and the second bus 93 in the actual first cylindrical lens 92 and the second cylindrical lens. The line corresponding to 96a is not drawn. Further, the arrangement of the cylindrical lenses is not limited to that shown in FIG. 7, and a single cylindrical lens may be used.

  According to the inspection apparatus of the present embodiment, it is also possible to provide an inspection apparatus capable of performing an inspection at high speed while suppressing charging of the sample to be inspected.

  In the above description, a series of “to circuits” includes a processing circuit, and the processing circuit includes an electric circuit, a computer, a processor, a circuit board, a quantum circuit, a semiconductor device, or the like. In addition, a common processing circuit (the same processing circuit) may be used for each “-circuit”. Alternatively, different processing circuits (separate processing circuits) may be used. The program that causes the processor or the like to execute may be recorded on a recording medium such as a magnetic disk device, a magnetic tape device, an FD, or a ROM (read only memory). Further, the "-storage unit", "-storage unit" or storage device includes a recording medium such as a magnetic disk device, a magnetic tape device, an FD, a ROM (Read Only Memory), and an SSD (Solid State Drive).

  The embodiments of the invention have been described with reference to examples. The above-described embodiments are merely given as examples, and do not limit the present invention. Further, the components of each embodiment may be appropriately combined.

  In the embodiment, the description of the configuration of the inspection apparatus and the manufacturing method thereof, which are not directly necessary for the description of the present invention, are omitted, but the required configuration of the inspection apparatus can be appropriately selected and used. . In addition, all inspection apparatuses which include the elements of the present invention and whose design can be appropriately changed by those skilled in the art are included in the scope of the present invention. It is intended that the scope of the invention be defined by the following claims and their equivalents:

12 Position Measurement Pattern 14 Focus Adjustment Pattern 20 Multi Beam 21 Opening 22 Hole 23 Shutter Plate 24 Control Electrode 25 Passage Hole 26 Counter Electrode 28 Pixel 29 Sub Irradiation Area 30 Membrane Area 31 Substrate 32 Outer Area 33 Support Base 34 Irradiation Area 36 Pixel 41 Individual control circuit 46 Amplifier 50, 52, 56 Storage device 54 Division unit 68 Positioning unit 70 Comparison unit 72 Vacuum ultraviolet light source 74 Vacuum ultraviolet light 76 Condensing unit 77 Condensing unit 78 Condensing unit 82 Spherical mirror 83 Spherical mirror Concave surface 84 Cylindrical mirror 85 Cylindrical mirror concave surface 90 Toroidal mirror 91 Toroidal mirror concave surface 92 First cylindrical lens 93 First convex surface 93a First generatrix 94 First plane 95 Second cylindrical lens 96 Second convex surface 96a Second Bus 97 Plane 100 inspection apparatus 101 substrate 102 electron beam column 103 inspection room 106 detection circuit 107 position circuit 108 comparison circuit 109 storage device 110 control computer 112 reference image creation circuit 114 stage control circuit 117 monitor 118 memory 119 printer 120 bus 122 laser measurement System 123 pattern memory 124 lens control circuit 126 blanking control circuit 128 deflection control circuit 129 retarding control circuit 130 carry-in / carry-out control circuit 132 drive mechanism 134 detection circuit 136 vacuum ultraviolet light source control circuit 142 stage drive mechanism 150 image acquisition mechanism 160 control System circuit 200 Electron beam 201 Electron gun 202 Illumination lens 203 Molded aperture array substrate 205, 213 Reduction lens 206 Restricted aperture substrate 207 Objective lens 208 Main deflector 209 Sub deflector 212 Batch blanking deflector 214 Beam separator 215 Shutter mechanism 216 Mirror 217, 218 Mark 219 Transmission mark 220 Electrode 221 Current detector 222 Multi-detector 224, 226 Projection lens 228 Deflector 230 Wide-area deflector 232, 234 Alignment coil 300 Multi-secondary electron 301 Secondary electron 302, 304 Deflector 306 Wide-area detector 330 Inspection area 332 Chip 333 Mask die 402 Beam separator 410 Lens array 411, 412, 413 Electrode

Claims (5)

An electron gun provided above the substrate 101 and irradiating the substrate 101 with an electron beam;
A detector for detecting secondary electrons emitted from the substrate 101;
A vacuum ultraviolet light source provided diagonally above the substrate 101 and irradiating vacuum ultraviolet light;
Light collecting means for collecting the vacuum ultraviolet light and irradiating the substrate 101 with the light;
An inspection device comprising:   The said condensing means has a spherical mirror which reflects the said vacuum ultraviolet light irradiated from the said vacuum ultraviolet light source, and a cylindrical mirror which reflects the said vacuum ultraviolet light reflected by the said spherical mirror, The claim 1 characterized by the above-mentioned. Inspection equipment.   The inspection apparatus according to claim 1, wherein the focusing unit includes a toroidal mirror that reflects the vacuum ultraviolet light emitted from the vacuum ultraviolet light source.   The inspection device according to any one of claims 1 to 3, wherein the vacuum ultraviolet light source is a deuterium lamp or an excimer lamp. The vacuum ultraviolet light source is an excimer lamp,
The inspection apparatus according to claim 1, wherein the condensing unit includes a cylindrical lens that transmits the vacuum ultraviolet light emitted from the vacuum ultraviolet light source.