JP2017134927A - Inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy maintenance inspection apparatus.SOLUTION: An inspection apparatus for observing a specimen placed on a stage by irradiating the specimen with an electron beam and detecting the electron beam from the specimen, includes: an electron gun for emitting the electron beam; a deflector for aligning the electron beam; multiple components including an electrode functioning as a lens, and a detector for detecting the electron beam from the specimen; a spacer provided between the multiple components; and a cylinder internally housing the multiple components and the spacer. The multiple components and the spacer have a disc shape with a cavity substantially in the center, and when they are laminated, the electron beam passes that cavity.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an inspection apparatus, and more particularly to an inspection apparatus that performs inspection by irradiating an electron beam onto the surface of a sample to be inspected.

  Inspection apparatuses such as an electron microscope used for inspection processes in semiconductor device manufacturing, microstructural observations of living organisms and the like in analysis of various industrial materials and pharmaceutical research are known (for example, Patent Documents 1 to 6). Such an inspection apparatus inspects by irradiating the surface of the inspection object with an electron beam and detecting secondary electrons from the inspection object. The inspection apparatus is configured by installing components (for example, an electron lens, a deflection electrode, and a secondary electron detector) in a cylindrical vacuum container called a lens barrel.

International Publication No. 2002/001596 JP 2007-48686 A Japanese Patent Laid-Open No. 11-132975 JP 2012-253007 A Japanese Patent Laying-Open No. 2015-201257 JP 2013-97869 A

  In an inspection device with such a structure, when a certain component part fails and needs to be replaced, or when it is regularly replaced due to maintenance, remove the component part or unit in the lens barrel and perform the work. After that, it is necessary to adjust the inspection apparatus (a particularly important adjustment is an optical axis adjustment for allowing the electron beam to pass through the center of each lens). When performing a large-scale maintenance, there is a problem that the time and labor required for the maintenance work itself and the time required for the optical axis adjustment become very long.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an inspection apparatus that can be easily maintained.

According to one aspect of the present invention, there is provided an inspection apparatus that observes a sample by irradiating the sample placed on the stage with an electron beam and detecting the electron beam from the sample, and irradiates the electron beam. A plurality of components including an electron gun, a deflector that aligns the electron beam, an electrode that functions as a lens, and a detector that detects an electron beam from the sample, and the plurality of components are provided between the components. A spacer, and a plurality of parts and a cylindrical body in which the spacer is housed, and each of the plurality of parts and the spacer has a substantially disk shape in the center, and is laminated to form the cavity. An inspection device through which the electron beam passes is provided.
Since the parts and spacers are disk-shaped, maintenance is easy.

In addition to the cavity through which the electron beam passes, it is preferable that each of the plurality of parts and the spacer is provided with a hole.
This facilitates the stacking of components and spacers.

More preferably, each of the plurality of parts and the spacer is provided with a plurality of holes having different shapes from each other in addition to the cavity through which the electron beam passes.
Thereby, the risk of mistaking the front and back of parts and spacers can be reduced.

  The hole can be used to align the plurality of components and spacers, and can serve as an exhaust hole when the cylinder is evacuated.

The spacer includes a low resistance portion having a lower resistance than other portions, a part of the low resistance portion is connected to the component disposed on the upper side, and another part of the low resistance portion is disposed on the lower side. It is desirable to be connected to the aforementioned parts.
It is more desirable that at least a part of the low resistance portion and the surface of the component are plated, and the low resistance portion and the component are connected via the plating.
Thereby, it can suppress that charge up generate | occur | produces in components.

  According to the present invention, since both the component and the spacer are disk-shaped, maintenance of the inspection apparatus is facilitated.

The figure which shows the whole structure of the electron beam inspection apparatus 1000. FIG. 9 shows a configuration of an electronic column 907. The top view of the component 1n. The top view of spacer 2m. FIG. 3 is an exploded cross-sectional view of the part 10, the spacer 20, and the part 11 near the cavity. FIG. 3 is an enlarged longitudinal sectional view of a peripheral edge portion of the focusing lens 11. The figure which shows the partial area | region of FPC70. FIG. 3 is an enlarged longitudinal sectional view of a peripheral edge portion of the focusing lens 11. The figure which shows the cross-section of the wiring of a condensing lens. The figure which shows the wiring structure in case the deflector itself consists of metals. The disassembled perspective view which shows a deflector and the spacer under it. The figure which shows the wiring structure in case the deflector 110 consists of the main body 103 which consists of ceramics, and the metal plating 106 formed in the surface. The figure which shows the structure of a TFE electron gun. The figure which shows the structure of the electron gun of another form. The enlarged view of the front-end | tip part of the electron emission fiber 326. FIG. The figure which shows the structure of the electron gun of another form. The figure which shows the structure of the MCP + anode type | mold detector of this Embodiment. The figure which shows the structure of the scintillator + light guide + PMT type detector of this Embodiment. The figure which shows the valve structure of this Embodiment. The figure which shows the other example of the valve mechanism of this Embodiment. The figure which shows the structure of the conventional deflector. The figure which shows the structure of the deflector of this Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Hereinafter, an electron beam inspection apparatus for inspecting a wafer or a mask for defects will be described as a sample observation apparatus for observing a sample using an electron beam.

1. Overall Configuration FIG. 1 is a diagram showing an overall configuration of an electron beam inspection apparatus 1000. As shown in FIG. 1, an electron beam inspection apparatus 1000 includes a sample carrier (load port) 901, a mini-environment 902, a load lock 903, a transfer chamber 904, a main chamber 905, a vibration isolation table 906, An electronic column 907, an image processing unit 908, and a control unit 909 are provided. The electronic column 907 is attached to the upper part of the main chamber 905.

  A sample carrier 901 stores a sample to be inspected. The mini-environment 902 is provided with a not-shown atmospheric transfer robot, sample alignment device, clean air supply mechanism, and the like. The sample in the sample carrier 901 is conveyed into the mini-environment 902, and alignment work is performed therein by the sample alignment device. The sample is transferred to the load lock 903 by a transfer robot in the atmosphere.

  The load lock 903 is exhausted from the atmosphere to a vacuum state by a vacuum pump. When the pressure falls below a certain value (for example, 1 Pa), the pressure is transferred to the main chamber 905 by a vacuum transfer robot (not shown) disposed in the transfer chamber 904. As described above, since the robot is disposed in the transfer chamber 904 that is always in a vacuum state, generation of particles and the like due to pressure fluctuations can be minimized.

  The main chamber 905 is provided with a stage 910 that moves in the x direction, the y direction, and the θ (rotation) direction, and an electrostatic chuck is installed on the stage 910. The sample itself is placed on the electrostatic chuck. Or a sample is hold | maintained at an electrostatic chuck in the state installed in the pallet or the jig | tool. The main chamber 905 is controlled to maintain a vacuum state by a vacuum control system (not shown). Further, the main chamber 905, the transfer chamber 904, and the load lock 903 are placed on a vibration isolation table 906 and configured to prevent vibration from the floor from being transmitted.

  In addition, one electronic column 907 is installed in the main chamber 905. The detection signal from the electronic column 907 is sent to the image processing unit 908 for processing. A control unit 909 controls the image processing unit 908 and the like. By this control, the image processing unit 908 can perform both on-time signal processing and off-time signal processing. On-time signal processing is performed during the inspection. When performing off-time signal processing, only an image is acquired and signal processing is performed later.

  Data processed by the image processing unit 909 is stored in a recording medium such as a hard disk or memory. Moreover, it is possible to display data on the monitor of the console as necessary. The displayed data is, for example, an observation image, an inspection area, a foreign matter number map, a foreign matter size distribution / map, a foreign matter classification, a patch image, and the like.

2. SEM Structure Next, the electronic column 907 will be described. The electron column 907 according to the present embodiment is an SEM in which an electron gun and an electron path through which an electron beam passes from the electron gun pass in a cylinder, and an electron beam irradiation detection system is formed. FIG. 2 is a diagram showing the configuration of the electronic column 907. The housing of the electron column 907 is constituted by the cylindrical body 50 and the electron gun housing 60. The cylindrical body 50 accommodates various components 10 to 19 and spacers 20 to 28 (described later) inside.

  The components 10 to 19 are, for example, a lens (electrostatic lens electrode) that acts as a lens for an electron beam, an aligner (for example, an electrode having a quadrupole or octupole structure) for adjusting the optical axis, a detector, and the like. . Spacers 20 to 28 that are insulating plates are arranged between the components 10 to 19, respectively. The parts 10 to 19 and the spacers 20 to 28 are made of ceramic as a base material, and their outer dimensions can be manufactured with an accuracy of micron order.

  The cylindrical body 50 has a cylindrical shape, and the electron gun housing 60 is a ceramic part that covers the upper opening of the cylindrical body and is hermetically sealed. Note that the cylindrical body 50 may be a hollow quadrangular prism. The cylinder 50 is also made of ceramic as a base material, and the inner size can be manufactured with submicron order accuracy.

  In the cylindrical body 50, as components 10 to 19, for example, a first deflector (aligner) 10, a focusing lens 11, a second deflector (aligner) 12, an aperture 13, a detector 14, a third deflector (aligner) 15, an objective The lens 16, the fourth deflector (aligner) 17, the fifth deflector (aligner) 18, and the electrode 19 are laminated from above in this order with spacers 20 to 28 interposed therebetween. Each of the components 10 to 19 has a hole in a portion corresponding to the vertical direction, and an electronic line EP is formed by these holes.

  The deflectors 10, 12, 15, and 17 perform electron beam alignment. The focusing lens 11 may be a deflector (aligner) or a ground electrode. The objective lens 16 is a high voltage electrode.

  One of the features of this embodiment is the shape of each component 10-19 and spacer 20-28. First, a shape common to the components 10 to 19 will be described as a component 1n (n = 0 to 9), and a shape common to the spacers 20 to 28 will be described as a spacer 2m (m = 0 to 8).

  FIG. 3 is a top view of the component 1n. The component 1n has a disk shape, and a cavity 1na is formed in the approximate center thereof. This cavity 1na becomes an electron line EP through which an electron beam passes. In addition, the component 1n is provided with one or a plurality of holes 1nb1 in addition to the cavity 1na for the convenience of stacking. Desirably, the part 1n is provided with a plurality of holes 1nb1, 1nb2 having different shapes, thereby reducing the risk of mistaking the front and back of the part 1n. Further, the component 1n is provided with a power supply wiring outlet 1nc.

  FIG. 4 is a top view of the spacer 2m. The spacer 2m has a disk shape, and a cavity 2ma is formed in the approximate center thereof. The cavity 2ma becomes an electron line EP through which an electron beam passes. The component 2m is provided with one or a plurality of holes 2mb1 in addition to the cavity 2ma for the convenience of stacking. Again, it is desirable that the spacer 2m be provided with a plurality of holes 1mb1, 1mb2 having different shapes. 2, the diameters of the cavities 20a to 28a of the spacers 20 to 28 may be smaller than the diameters of the cavities 10a to 19a of the components 10 to 19.

  The components 10 to 19 and the spacers 20 to 28 are a rod-shaped jig temporarily placed in the cylinder 50, and a hole 19b1 of the component 19, a hole 28b1 of the spacer 28, a hole 18b1 of the component 18, a hole 27b1 of the spacer 27. .. Stacked by sequentially passing through the holes 10b1 of the component 10, and finally the jig is removed. Thus, the holes can be used for alignment when the components 10 to 19 and the spacers 20 to 28 are laminated. Further, the holes 1nb1, 1nb2, 2mb1, and 2mb2 serve as exhaust holes when the cylinder 50 is evacuated to increase conductance and improve exhaust efficiency.

  By doing so, it becomes possible to assemble the electronic column 907 with high positional accuracy between the components 10 to 19 (particularly the electrode acting as an electrostatic lens), and the optical axis adjustment after maintenance becomes very easy. . Furthermore, in the electronic column 907 configured with such a structure, for example, when any of the internal components deteriorates and needs to be replaced, only that component needs to be replaced, so that maintenance is facilitated. In addition, it is possible to reduce the cost of repairs. Moreover, the freedom degree of arrangement | positioning, structure change, etc. of the components 10-19 becomes high.

FIG. 5 is an exploded sectional view of the part 10, the spacer 20, and the part 11 near the cavity.
The component 10 is made of a conductive material. The shape is thin in the vicinity of the cavity 10a. The upper surface of this portion is plated with gold 10d, and the lower surface is similarly plated 10e. The same applies to the component 11.

  The spacer 20 is made of an insulating material such as ceramic. The vicinity of the cavity 20a of the spacer 20 is thick, and the upper surface of this portion is plated with gold 20e, and the lower surface is similarly plated 20f. When the component 10, the spacer 20, and the component 11 are laminated, the plating 10e of the component 10 and the plating 20e of the spacer 20 are in contact with each other, and the plating 20f of the spacer 20 and the plating 11d of the component 11 are in contact with each other.

Further, the spacer 20 has a low resistance portion 20d having a lower resistance than other portions. The low resistance portion 20d is not a perfect insulating material, and a low resistance ceramic whose resistance value is controlled to about 10 ⁹ to 10 ¹² Ω · cm can be used. The low resistance portion 20d is desirably formed on the surface on the cavity 20a side, and has a width of, for example, several microns. Thereby, the upper part of the low resistance part 20d is connected to the component 10 (more specifically, the plating 10e) disposed on the upper side through the plating 20e. The lower portion of the low resistance portion 20d is connected to the component 11 (more specifically, the plating 11d) disposed on the lower side through the plating 20f.

A high voltage of about 5 kV to 10 kV can be applied to the components 10 and 11. Then, if there is no low-resistance portion 20d, there is a possibility that the parts 10 and 11 may be charged up or a discharge due to the charge-up may occur, which adversely affects the inspection.
In the present embodiment, by providing the low resistance portion 20, the component 10, the low resistance portion 20 d of the spacer 20 and the component 11 are conducted, and the above-described adverse effect can be avoided.

  In addition, the low resistance ceramic forming the low resistance portion 20d tends to have a resistance value that increases in the depth direction from the material surface as a characteristic resulting from the manufacturing method. Therefore, in this embodiment, for the purpose of surely connecting the spacer 20 and the upper and lower parts 10 and 11, the vicinity of the cavity 20a of the spacer 20 is processed to be slightly thick, and plating 20e and 20f is applied to the processed portion. With such a structure, the spacer 20 and the components 10 and 11 are reliably connected.

  The component 10, the spacer 20, and the component 11 have been described above, but the other components and spacers may be the same. In particular, the electrode component to which a high voltage is applied and the adjacent spacer are shaped as shown in FIG. Is desirable.

3. Wiring Structure Next, the wiring structure of the components 10 to 19 in the electronic column 907 will be described. In each of the components 10 to 19, it is necessary to draw out a conductive wire for electrical connection with the power source to the outside of the cylindrical body 50.

3-1. The vertical cross-sectional structure of the wiring The vertical cross-sectional structure of the wiring in the electron column of the present embodiment will be described below by taking the focusing lens 11 as an example.

3-1-1. When the focusing lens 11 is made of metal FIG. 6 is an enlarged longitudinal sectional view of the peripheral edge of the focusing lens 11. The example of FIG. 6 shows a wiring structure when the focusing lens 11 is made of metal. The cylinder 50 is provided with a flexible printed cable (FPC) 70 as a wiring film so as to cover the outer peripheral surface along the outer peripheral surface. FIG. 7 is a diagram illustrating a partial region of the FPC 70. The FPC 70 has a three-layer structure of a polyimide resin layer 71, a conductive formation layer 72, and a polyimide resin layer 73. A conductive line EL made of copper is formed on the conductive formation layer 72.

  The FPC 70 and the cylindrical body 50 are provided with wiring holes 74 and 51 at positions corresponding to the terminals of the focusing lens 11, and conductive contact pins 80 are inserted into the wiring holes 74 and 51. A screw thread is formed in the shaft portion of the contact pin 80, and a thread groove is formed in the wiring hole 51 of the cylindrical body 50. The contact pin 80 and the cylindrical body 50 are screwed together, so that the contact is made. The pin 80 is held by the cylindrical body 50.

  The wiring hole 74 has a size equal to or larger than the diameter of the head of the contact pin 80 in the polyimide resin layer 71, and the shaft portion of the contact pin 80 in the conductive forming layer 72 and the polyimide resin layer 73. The flange portion 741 is formed on the outer surface of the conductive formation layer 72 and has a size equal to or larger than the diameter (smaller than the diameter of the head). When the contact pin 80 is screwed into the cylindrical body 50 and the head of the contact pin 80 comes into contact with the flange portion 741 of the FPC 70, the contact pin 80 and the conductive wire EL are electrically connected, and the contact pin 80 The 80 cylinders 50 are positioned in the thickness direction.

  The focusing lens 11 is made of metal and itself is an electrode. A contact hole 111 as a terminal is formed in the focusing lens 11 at a position corresponding to the wiring holes 74 and 51, and a thread groove is formed on the inner surface thereof. The contact pin 80 is screwed into the screw groove of the wiring hole 51, further screwed into the contact hole 111, and the tip of the contact pin 80 contacts the bottom of the contact hole 111, thereby contacting the metal focusing lens 11. The pin 80 is electrically connected.

  With the above configuration, the conductive wire EL and the focusing lens 11 are electrically connected via the contact pin 80. The conductive line EL is formed in the conductive formation layer 72 inside the FPC 70 as shown in FIG. 7, and is connected to a power source at an appropriate location via an external wiring. That is, the conductive line EL formed in the conductive formation layer 72 connects the external power source to the components of the electronic column 907 via the contact pins 80.

Further, a metal ground coating 90 is applied to the front surface of the cylinder 50 and / or the back surface of the FPC 70 except for the wiring holes 74 and 51. When the voltage supplied by the above wiring structure is as large as 100V, it becomes about 10,000V. Therefore, if a slight gap is formed between the cylinder 50 and the FPC 70, a spark is generated there. As a result, each component and the FPC 70 may be damaged. The ground coating 90 can prevent such a spark from occurring by discharging a high voltage applied to the gap between the cylinder 50 and the FPC 70 to the ground.
3-1-2. When the focusing lens 11 is metal-plated

  FIG. 8 is an enlarged longitudinal sectional view of the peripheral edge of the focusing lens 11. The example of FIG. 8 shows a wiring structure when the focusing lens 11 is metal-plated. The cylinder 50 is provided with a flexible printed cable (FPC) 70 as a wiring film shown in FIG. 7 so as to cover the outer peripheral surface along the outer peripheral surface.

  The FPC 70 and the cylindrical body 50 are provided with wiring holes 74 and 51 at positions corresponding to the focusing lens 11, and conductive contact pins 80 are inserted into the wiring holes 74 and 51. A screw thread is formed in the shaft portion of the contact pin 80, and a thread groove is formed in the wiring hole 51 of the cylindrical body 50. The contact pin 80 and the cylindrical body 50 are screwed together, so that the contact is made. The pin 80 is held by the cylindrical body 50.

  When the contact pin 80 is screwed into the cylindrical body 50 and the head of the contact pin 80 comes into contact with the flange portion 741 of the FPC 70, the contact pin 80 and the conductive wire EL are electrically connected, and the contact pin 80 The 80 cylinders 50 are positioned in the thickness direction.

  The focusing lens 11 has a structure in which a metal plating 113 serving as a conductive wire is formed on the surface of an insulator (specifically, ceramic) main body 112. In the focusing lens 11, contact holes 111 serving as terminals are formed at positions corresponding to the wiring holes 74 and 51. A cylindrical metal bush 114 having a thread groove formed on the inner peripheral surface is press-fitted into the contact hole 111. A via 115 electrically connected to the metal plating 113 is formed at the bottom of the contact hole 111. The via 115 is formed by forming a via hole communicating with the contact hole 111 on the surface of the main body 112 and injecting metal into the via hole. The via 115 is injected from the via hole and reaches the bottom of the contact hole 111. The metal plating 113 is formed on the surface of the main body 112 after the via 115 is formed in this manner, and the metal plating 112 and the via 115 are electrically connected.

  With the above configuration, the conductive line EL and the metal plating 113 of the focusing lens 11 are electrically connected via the contact pin 80 and the via 115. The conductive line EL is formed in the conductive formation layer 72 inside the FPC 70 as shown in FIG. 7, and is connected to a power source at an appropriate location via an external wiring. That is, the conductive line EL formed in the conductive formation layer 72 connects the external power source to the components of the electronic column 907 via the contact pins 80.

  Further, a metal ground coating 90 is applied to the front surface of the cylinder 50 and / or the back surface of the FPC 70 except for the wiring holes 74 and 51. When the voltage supplied by the above wiring structure is as large as 100V, it becomes about 10,000V. Therefore, if a slight gap is formed between the cylinder 50 and the FPC 70, a spark is generated there. As a result, each component and the FPC 70 may be damaged. The ground coating 90 can prevent such a spark from occurring by discharging a high voltage applied to the gap between the cylinder 50 and the FPC 70 to the ground.

  According to the above configuration, since the main body 112 of the focusing lens 11 is made of ceramic, as described above, the amount of deformation due to its thermal expansion is small, and high accuracy on the submicron level can be realized. Further, the body 112 of the focusing lens 11 is made of ceramic, and the spacers 20 to 28 and the cylindrical body 50 are also made of ceramic, so that the thermal expansion coefficients of these parts can be made the same, and the assembly of the electronic column 907 is possible. The accuracy of the coaxiality in the sub-micron level can be achieved.

3-2. Next, the cross-sectional structure of the wiring to the components 10 to 19 in the electronic column 907 will be described.

3-2-1. First, the cross-sectional structure of the wiring of the focusing lens 11 will be described. FIG. 9 is a diagram showing a cross-sectional structure of the wiring of the focusing lens. However, the holes 11a1 and 11a2 are omitted. As shown in FIG. 9, two electron beam irradiation detection systems are formed side by side inside the cylinder 50 of the electron column 907.

  The spacers 20 and 21 respectively disposed on the upper side and the lower side of the focusing lens 11 have an outer peripheral shape that matches the inner periphery of the cylindrical body 50. Circular holes 201 and 211 are formed in the spacers 20 and 21 corresponding to the electron beam EP of the electron beam irradiation detection system. A focusing lens 11 is provided between the spacers 20 and 21. In the example of FIG. 9, the focusing lens 11 is configured by coating a main body 112 made of ceramic with a metal plating 113. The main body 112 of the focusing lens 11 has an outer peripheral shape that matches the inner periphery of the cylindrical body 50.

  The main body 112 of the focusing lens 11 is coated with a metal plating 113 in a range larger than the holes 201 and 211 of the spacers 20 and 21 at positions corresponding to the holes 201 and 211 of the spacers 20 and 21, respectively. These metal platings 113 serve as the electrodes of each focusing lens 11. The respective electrodes in the two focusing lenses 11 are electrically separated.

  In the main body 112 of the focusing lens 11, circular holes 116 smaller than the holes 201 and 211 of the spacers 20 and 21 are formed at positions corresponding to the holes 201 and 211 of the spacers 20 and 21, respectively. These holes 201, 116, and 211 form an electronic line EP. From the holes 201 and 211 formed in the spacers 20 and 21, the focusing lens 11 (the metal plating 113 portion, that is, the electrode) in which the holes 116 are formed is exposed.

  The focusing lens 11 has one electrode, and there is one wiring for each focusing lens 11. As shown in FIG. 9, the wiring to this electrode can be drawn to the outside of the cylinder pair 50 from the position closest to the cylinder 50 in the focusing lens 11. In FIG. 9, the illustration of the FPC 70 provided on the outer periphery of the housing 50 is omitted. In the example of FIG. 9, as described with reference to FIG. 6, the contact pin 801 is directly screwed into the focusing lens 11 to realize electrical contact between the electrode and the contact pin 801 in the focusing lens 11.

  In addition, about said form, a deformation | transformation is possible. For example, the conductive lines may be drawn from the electrodes of the two focusing lenses 11, and the conductive lines may be merged in the cylindrical body 50 and then drawn out of the cylindrical body 50 using one contact pin 801. . In this case, one contact pin 801 can be screwed into the cylinder 50 from an intermediate position between the two electron beam irradiation detection systems, for example. Alternatively, the electrodes of each focusing lens 11 may be brought into contact to electrically connect one of the electrodes and the contact pin 801.

  Further, in the above embodiment, the two focusing lenses 11 are configured by covering the body 112 made of ceramic with the metal plating 113 at a position corresponding to the electron beam irradiation detection system. When the main body is made of metal, one contact pin 801 may be connected to the main body made of metal.

3-2-2. Deflector Next, the cross-sectional structure of the deflector wiring will be described.

3-2-2.1.1 When one electron beam irradiation detection system is formed in one electron column

3-2-2-1-1. When the deflector is made of metal FIG. 10 is a diagram showing a wiring structure when the deflector itself is made of metal. FIG. 11 is an exploded perspective view showing the deflector and the spacer below the deflector. The deflector 100 in this example has four electrodes. The deflector 100 is divided into four electrodes 101 each having a sector shape. The outer periphery of each electrode 101 matches the inner periphery of the cylinder 50. When each electrode 101 is disposed with a gap 102 and the outer periphery in contact with the inner periphery of the cylindrical body 50, a circular hole serving as an electron line EP is formed at the center.

  The spacer 200 provided under the deflector 100 is separated from the vertical spacer portion 201 in order to secure a space between adjacent electrodes and a donut-shaped vertical spacer portion 201 for securing a space with a lower part. It consists of four standing circumferential spacer portions 202. Each electrode 101 of the deflector 100 is disposed on the lower part via the longitudinal spacer portion 201 of the spacer 200 and is disposed with a gap 102 between each other via the circumferential spacer portion 202 of the spacer 200. .

  Contact pins 802 are screwed into the respective electrodes 101 from the outside of the cylindrical body 50 to ensure electrical connection between the respective contact pins 802 and the respective electrodes 101. The connection structure between the electrode 101 and the contact pin 802 is as described with reference to FIG. In FIG. 10, the FPC 70 is not shown.

3-2-2-1-2. When the Deflector is Metal-Plated FIG. 12 is a diagram showing a wiring structure in the case where the deflector 110 is made of a ceramic main body 103 and a metal plating 106 formed on the surface thereof. Also in this example, the deflector 110 has four electrodes. The main body 103 of the deflector 110 has a donut shape with a circular hole formed in the center, and cutouts 105 are cut in four directions from the hole. An electrode 104 is formed between adjacent notches 105. A metal plating 106 is coated around the circular hole. The metal plating 106 is separated by a notch 105, and thereby four electrodes 104 are formed.
The spacer 210 disposed under the deflector 110 has a donut shape having a hole larger than the hole of the deflector 110 inside.

  Contact pins 803 are screwed into the respective electrodes 104 from the outside of the cylindrical body 50 to ensure electrical connection between the respective contact pins 803 and the respective electrodes 104. The connection structure between the metal plating 106 of the electrode 104 and the contact pin 803 is as described with reference to FIG. In FIG. 12, the FPC 70 is not shown.

4). Electron Gun As described above, a conventional TFE electron gun or an FE electron gun can be used for the electron gun 30, but other types of electron guns described below may be used.

4-1. TFE electron gun First, the TFE electron gun will be described. FIG. 13 is a diagram showing the configuration of the TFE electron gun. The TFE electron gun 31 includes a cathode tip 311 having a sharp tip, a Wehnelt 312, and an anode 313. The size in the width direction of the TFE electron gun 31 is about 20 mm. Therefore, when the two TFE electron guns 31 are brought close to the maximum, the pitch of the irradiated electron beam is about 20 mm. In the configuration described above, the heater power source 314 and the Wehnelt power source 316 are housed in the electron gun housing 60 in addition to the cathode tip 311, the Wehnelt 312 and the anode 313.

  A heater voltage is applied to the cathode chip 311 from the heater power supply 314, and a cathode voltage of about −50 to −10 kV is applied from the cathode power supply 315. Further, a variable voltage is applied to the Wehnelt 312 from the Wehnelt power source 316.

  The cathode chip 311 is in a state where the temperature rises and electrons are easily emitted by applying a heater voltage. The cathode chip 311 emits electrons from the vicinity of its tip when a cathode voltage is further applied. The anode 313 extracts electrons emitted from the vicinity of the tip of the cathode tip 311 and guides the electron beam to the electron line.

4-2. Other forms of electron gun (1)
FIG. 14 is a diagram showing a configuration of an electron gun of another form. The electron gun 32 includes a laser diode 321, a first lens 322, a magnetic field coil 323, a gas sealing tube 324, a second lens 325, and an electron emission fiber 326, and emits electrons from the tip of the electron emission fiber 326. . In addition, a Wehnelt 327 and an anode 328 are provided at the tip of the electron emission fiber 326, and the electron gun 32 draws electrons emitted from the tip of the electron emission fiber 326 by these configurations, To the electronic track.

  The laser diode 321 emits laser light as a laser light source. The first lens 322 collects the laser light emitted from the laser diode 321. The first lens 322 is designed and arranged so as to focus the laser beam in the gas sealing tube 324. In the gas sealing tube 324, a small plasma space (spot plasma) is formed by the focused laser beam. At this time, the magnetic field coil 323 forms an induction magnetic field, so that a plasma state can be easily formed, and the shape of the plasma can be controlled (for example, rounded).

  Electromagnetic emission (invisible light) such as DUV (deep ultraviolet), UV (ultraviolet), and X-rays is generated by the generation of a small plasma space in the gas sealing tube 324, and this is condensed by the second lens 325 to emit electrons. The signal is input to the input end of the fiber 326 (left end in FIG. 14).

  FIG. 15 is an enlarged view of the tip portion of the electron emission fiber 326. The electron emission fiber 326 includes a core 3261, a clad 3262, a metal coat 3263 such as Cr or CrN, and a photoelectric material 3264. As the electron emission fiber 326, for example, a fiber made of a glass material or a fiber made of quartz glass can be used. The vicinity of the tip of the electron emission fiber 326 has a tapered shape, and the end of the core 3261 is formed to have a diameter of 0.5 to 50 nm at the tip. The clad 3252 is formed around the core 3261. The photoelectric material 3264 is provided at the tip, and the tips of the core 3261 and the clad 3262 are coated. Note that the photoelectric material 3264 may be coated only on the tip of the core 3261. The photoelectric material 3264 is made of Au or Ru and has a thickness of 10 to 20 nm. When the photoelectric material 3264 receives light, the photoelectric material 3264 generates an amount of electrons corresponding to the amount of light.

  The metal coat 3263 is formed on the outside of the clad 3262 and on the periphery of the photoelectric material 3264 (the portion where the photoelectric material 3264 coats the tip of the clad 3262). The metal coat 3263 is connected to a power supply of 0 to −10 kV. The metal coat 3263 is electrically connected to the photoelectric material 3264 by overlapping with the periphery of the photoelectric material 3264. In addition, since the metal coat 3263 overlaps with the peripheral portion of the photoelectric material 3264, it is possible to suppress the spread of the photoelectron generation portion due to the DUV that has oozed from the core 3261. With such a structure, the metal coat 3263 functions as a conductive line that electrically connects the power source and the photoelectric material 3264, and applies the voltage of the power source to the photoelectric material 3264.

  The invisible light rays such as DUV, UV, and X-rays that have entered the core 3261 from the input end of the electron emission fiber 326 having such a configuration are repeatedly totally reflected at the boundary between the core 3261 and the clad 3262, and are thus output to the output end. Proceed toward (right end in FIG. 14). Invisible rays such as DUV, UV, and X-rays that have propagated through the core 3261 are incident on the photoelectric material 3264 at the tip of the electron emission fiber 326. The photoelectric material 3264 emits electrons according to the intensity of the incident invisible light such as DUV, UV, and X-ray.

  The tip of the electron emission fiber 326, that is, the electron emitted from the photoelectric material 3264 is drawn out by the Wehnelt 327 and the anode 328 and guided to the electron line formed by the first deflector 10 and the like.

  Among the components of the electron gun 32, only the tip portion of the electron emission fiber 326, the Wehnelt 327 and the anode 328 need to be accommodated in the vacuum, that is, in the electron gun housing 60. Elements can be placed in the atmosphere. For this reason, the electron gun 32 can reduce the interval between electron beams in a multi-SEM structure in which a plurality of electron beam irradiation detection systems are formed in one electron column 907, and a limited range within the electron column 907. This is advantageous in that more electron beam irradiation detection systems can be formed.

  Further, in the TFE electron gun 31 described above, when the output is increased, electrons are emitted not only from the tip of the cathode chip but also from around the tip, and the electron beam passes through an extra orbit and causes charge-up. There is a fear. On the other hand, the electron gun 32 can reliably emit electrons only from the tip of the electron emission fiber 326, and travels an orbit where an electron beam to be irradiated (hereinafter also referred to as “irradiation beam”) is not desired. Compared with the TFE electron gun 31, the resolution of the observation image can be improved by preventing or reducing blurring of the observation image due to passing.

  Further, the energy width of the electron beam irradiated from the electron gun 32 is as narrow as about 0.05 to 0.5 eV, and the electron gun 32 has more electrons with uniform energy than the TFE electron gun 31. Can be released.

4-3. Other forms of electron gun (2)
FIG. 16 is a diagram showing a configuration of an electron gun of another form. Similar to the electron gun 32, the electron gun 33 includes a laser diode 331, a first lens 332, a magnetic field coil 333, a gas sealing tube 334, and a second lens 335. The electron gun 33 includes an electron emission element 336 instead of the electron emission fiber 326 of the electron gun 32, and emits electrons from the electron emission surface (output surface) of the electron emission element 336. In addition, a Wehnelt 337 and an anode 338 are provided at the tip of the electron emission surface of the electron emission device 336, and by these, electrons emitted from the electron emission surface of the electron emission device 336 are extracted, and an electron beam is converted into an electron. Lead to the track.

  The laser diode 331 emits laser light as a laser light source. The first lens 332 condenses the laser light emitted from the laser diode 331. The first lens 332 is designed and arranged so as to focus the laser light in the gas sealing tube 334. In the gas sealing tube 334, a small plasma space (spot plasma) is formed by the focused laser beam. At this time, the magnetic field coil 333 forms an induction magnetic field, so that a plasma state can be easily formed, and the shape of the plasma can be controlled (for example, rounded).

  Due to the generation of a small plasma space in the gas sealing tube 334, invisible light rays such as DUV, UV, and X-rays are generated, which are collected by the second lens 335 and input to the electron emission element 336 (left side in FIG. 16). Screen).

  The electron-emitting device 336 includes a base material 3361 made of quartz, an aperture 3362 formed on the input surface side of the base material 3361, a metal coat 3363, and a photoelectric material 3364 provided on the output surface side of the base material 3361. Become. The photoelectric material 3364 is made of Au or Ru and has a thickness of 10 to 20 nm. When the photoelectric material 3264 receives light, the photoelectric material 3264 generates an amount of electrons corresponding to the amount of light.

  The metal coat 3363 is formed on the output surface side of the base material 3361. The metal coat 3363 is connected to a power supply of 0 to −10 kV. The metal coat 3363 is electrically connected to the photoelectric material 3364 by overlapping with the periphery of the photoelectric material 3364. With such a structure, the metal coat 3363 functions as a conductive line that electrically connects the power source and the photoelectric material 3364, and applies the voltage of the power source to the photoelectric material 3364.

  Invisible rays such as DUV, UV, and X-rays that have entered the substrate 3361 through the aperture 3362 from the input surface of the electron-emitting device 336 having such a configuration travel toward the output surface (the right end in FIG. 16). . Invisible light rays such as DUV, UV, and X-ray that have propagated through the base material 3361 are incident on the photoelectric material 3364 on the output surface side of the base material 3361. The photoelectric material 3364 emits electrons according to the intensity of the incident invisible light such as DUV, UV, and X-ray.

  Electrons emitted from the output surface of the electron-emitting device 336, that is, the photoelectric material 3364, are extracted by the anode 338 and guided to the electron line formed by the first deflector 10 and the like.

  Among the components of the electron gun 33, only the electron-emitting device 336 and the anode 338 must be accommodated in the vacuum, that is, in the electron gun housing 60, and the other components are disposed in the atmosphere. Is possible. For this reason, the electron gun 33 can shorten the interval between the electron beams in a multi-SEM structure in which a plurality of electron beam irradiation detection systems are formed in one electron column 907, and a limited range within the electron column 907. This is advantageous in that more electron beam irradiation detection systems can be formed.

  In addition, the electron gun 33 can reliably emit electrons only from the photoelectric material 3364 of the electron-emitting device 336, and prevents or reduces blurring of an observation image caused by an irradiation beam passing through an undesired trajectory. Compared with the electron gun 31, the resolution of the observation image can be improved. Furthermore, the energy width of the electron beam irradiated from the electron gun 33 is as narrow as about 0.05 to 0.5 eV, and the electron gun 33 has more electrons with uniform energy than the TFE electron gun 31. Can be released. The electron gun 33 is also advantageous in that it does not require Wehnelt compared to the TFE electron gun 31. Further, since the electron gun 33 has a simple structure, it can be manufactured at a low cost, and its cost may be about 1/3 to 1/5 that of a conventional TFE electron gun.

  Further, the electron gun 33 has an advantage that the transmittance of the generated electron beam can be increased by not using Wehnelt. That is, if there is Wehnelt, the size and position of the 1st crossover changes depending on the electron energy, the Wehnelt voltage, and the anode voltage, and the irradiation beam may spread, resulting in poor transmittance. In contrast, since the electron gun 33 does not use Wehnelt, the transmittance of the generated electron beam can be increased by using the photoelectric material 3364 as a substantial light source.

5. Detector As described above, the electron column 907 includes the detector 14 in the electron beam irradiation detection system. The electron beam is emitted from the electron gun 30 and irradiates the sample through the electron line. When the sample is irradiated with an electron beam, secondary electrons and the like are generated from that portion. Secondary electrons and the like travel in the direction opposite to the direction of the irradiation beam IB through the electron beam irradiation detection system by the pulling electric field. The detector 14 collects and detects secondary electrons and the like that travel backward from the sample in this way. Below, two embodiment is described as a concrete structure of a detector.

5-1. MCP + Anode Type FIG. 17 is a diagram showing the configuration of the MCP + anode type detector of the present embodiment. The detector (MCP + anode type) 141 has a tube 1414 around the irradiation beam IB from the electron gun 30 so as to surround it. The tube 1414 maintains a reference potential (usually a GND potential). The detector 141 further includes an insulating ceramic 1411, an anode 1412, and a microchannel plate (MCP) 1413 as an electronic amplifier.

  The ceramic 1411 supports the tube 1414, the anode 1412, and the MCP 1413 as a support. A support hole is provided in the center of the ceramic 1411, and the outer peripheral surface of the tube 1414 is supported by this support hole. A conductive film 1415 is coated on the upper surface of the ceramic 1411 so that the ceramic 1411 is not charged. Note that, instead of coating the conductive film 1415, a conductive material component may be installed, or a process of reducing the resistance of the surface layer of the ceramic 1411 may be performed.

  The anode 1412 and the MCP 1413 are provided with holes through which the tube 1414 passes. The anode 1412 and the MCP 1413 surround the tube 1414 without contacting the tube 1414. The MCP 1413 is provided below the anode 1412, and the anode 1412 is provided below the ceramic 1411. Both the MCP 1413 and the anode 1412 are supported by a ceramic 1411 as a support.

  The irradiation beam IB passes through the tube 1414 and then passes through the objective lens, the deflector, and the like, and is irradiated onto the sample SM. The secondary electrons SE emitted from the sample by the irradiation beam IB are pulled up in the upstream direction through the vicinity of the center of the electron line by the pulling electric field. When approaching the MCP 1413, they are off the center and enter the MCP 1413. . As shown in FIG. 20, the trajectory curves outward in front of the MCP 1413. A positive voltage is applied to the input surface of the MCP 1413 in order to easily form such an orbit, that is, to increase the amount of secondary electrons SE drawn into the MCP 1413. For example, the amount of pulling can be increased by applying a voltage of about 0 to 500 V to the input surface of the MCP 1413.

  The MCP 1413 is provided with an MCP input terminal (MCPin) 1416 and an MCP output terminal (MCPout) 1417 of the secondary electrons SE. A high positive voltage of about 300 to 2000 V is normally applied to the MCP output terminal 1417. Thereby, electrons incident on the MCP input end 1416 are repeatedly amplified in the microtube of the MCP 1413, emitted from the MCP output end 1417, and absorbed by the anode 1412. At this time, a voltage higher by 300 to 3000 V than the MCP output terminal 1417 is normally applied to the anode 1412. Therefore, the electrons emitted from the MCP output end 1417 after amplifying the amount of electrons are extracted in the direction of the anode 1412 and collide with the anode 1412 to be absorbed.

  By directly measuring the current value of the anode 1412 or converting the current value of the anode 1412 into a voltage and measuring it, the amount of SE emitted from the sample such as secondary electrons can be measured. Further, when the irradiation beam IB is scanned by a deflector or the like, the amount of secondary electrons such as SE from the sample is acquired, and the intensity of the electron amount is shown two-dimensionally while dividing the time, secondary electrons as an inspection image are obtained. An image can be obtained. In this case, the time break corresponds to the place.

  In the conventional method, it is difficult to reduce the size due to the size and withstand voltage of the component itself, and even if the size can be reduced, the collection rate of secondary electrons and the like is low. According to the present embodiment, it is possible to reduce the size of a multi-SEM in which a plurality of electron beam irradiation detection systems are provided in one cylinder by an electrostatic lens. And it has the following structures as a device for not reducing a collection rate. That is, when the scanning width on the sample surface is 1 to 200 μm, for example, the detector 14 is installed at a distance of 200 times or more the scanning width from the sample surface. If the distance from the sample surface to the detector 14 is too short, it becomes difficult to increase the efficiency of collecting secondary electrons and the like from the sample surface at the outer periphery of the detector 14. In this Embodiment, 40-80% of collection rate can be achieved by having said structure.

  As described above, this embodiment can achieve both a reduction in size and a high collection efficiency in a multi-SEM in which a plurality of electron beam irradiation detection systems are provided in one cylinder, and a data rate of 200 to 2000 MPPS can be achieved. realizable.

5-2. Scintillator + Light Guide + PMT Type FIG. 18 is a diagram showing a configuration of a scintillator + light guide + PMT type detector according to the present embodiment. The detector 148 has a tube 1414 around the electron beam IB from the electron gun 30 so as to surround it. The tube 1414 maintains a reference potential (usually a GND potential). The detector 141 further includes an insulating ceramic 1411, a scintillator 1419, a light guide 1420, and a photomultiplier tube (PMT) 1421 as a photomultiplier tube.

  A support hole is provided in the center of the ceramic 1411, and the outer peripheral surface of the tube 1414 is supported by this support hole. A conductive film 1415 is coated on the upper surface of the ceramic 1411 so that the ceramic 1411 is not charged. Note that, instead of coating the conductive film 1415, a conductive material component may be installed, or a process of reducing the resistance of the surface layer of the ceramic 1411 may be performed.

  The scintillator 1419, the light guide 1420, and the PMT 1421 are provided on the same plane. With reference to the irradiation beam IB, the scintillator 1419 is provided on the innermost side, the light guide 1420 is provided on the outer side, and the PMT 1421 is further provided on the outer side. The scintillator 1419 has a rod shape, and eight scintillators 1419 are provided around the tube 1414. The scintillator 1419 is arranged so that its longitudinal direction is in the radial direction of a circle centered on the irradiation beam IB.

  The irradiation beam IB passes through the tube 1414 and then passes through the objective lens, the deflector, and the like, and is irradiated onto the sample SM. Secondary electrons such as SE emitted from the sample SM by the irradiation beam IB are pulled up in the upstream direction by passing through the vicinity of the center of the electron line by the pulling electric field. Is incident on. The trajectory is curved outward in front of the scintillator 1419 as shown in FIG. A positive voltage is applied to the input surface of the scintillator 1419 in order to easily form such a trajectory, that is, to increase the amount of secondary electrons SE drawn into the scintillator 1419. For example, the amount of pulling can be increased by applying a voltage of about 0 to 500 V to the input surface of the scintillator 1419.

  The scintillator 1419 converts the incident electrons into light having an intensity corresponding to the amount of the electrons. The scintillator 1419 is coated with a transparent conductive film as an electrode on its surface (upper surface or bottom surface) so that a positive voltage can be applied and the transmittance is not reduced when converted from electrons to light. In this way, the electrons incident on the scintillator 1419 are converted into light, and the light enters the light guide 1420. Light travels through the light guide 1420 and enters the PMT 1421. The PMT 1421 converts incident light into electrons, further performs electronic amplification on the electrons, and outputs them as electronic signals. This electronic signal corresponds to the intensity of light incident on the PMT 1421.

  Note that the number of scintillators 1419 is not limited to eight, and may be two, four, twelve, sixteen, or other numbers. Further, the scintillator 1419 may be one instead of a plurality. By using a plurality of scintillators 1419, the amount of secondary electrons that can be collected can be increased. Further, by using a plurality of scintillators 1419, the distribution of the collection rate depending on the location of the detector 14 is measured, and secondary electrons and the like can be collected evenly. Whether it is biased can be detected.

  If the collection position of secondary electrons or the like is biased, the correction can be performed immediately. If the collection position is biased, the progress of damage varies depending on the location, so that when the position changes, the amount of current (brightness) varies. In such a case, it is necessary to calibrate each time, and the loss time of the apparatus increases. If secondary electrons, etc. are collected uniformly, even if the state changes, it can be operated immediately without any fluctuations in brightness, so it is normal to immediately detect the correction of the collection position and correct it. It can be returned to the state.

  Further, an oblique mirror may be built in the scintillator. In this case, after electrons are converted into light on the surface of the scintillator, the light is reflected toward the PMT 1421 by the mirror, so that the light is efficiently transmitted to the PMT 1421. Furthermore, an electron / light conversion film may be coated on the oblique mirror surface. In this case, since the electron / light conversion is performed on the mirror surface, the light is reflected in the PMT direction immediately after the conversion and light can be efficiently transmitted to the PMT.

6). Valve Mechanism As described above, the inside of the electron gun housing 60 is evacuated by the vacuum pump 40. Although regular maintenance is required for the electron beam detector 100, a valve structure is used to maintain the vacuum state of the electron gun housing 60 during maintenance. That is, by making the electron gun housing 60 a sealed space with a valve, the electron gun housing 60 can be kept in a vacuum state even during maintenance.

  FIG. 19 is a view showing the valve structure of the present embodiment. As described above, the electron gun housing 60 is provided with the electron guns 30 and 30 and is brought into a vacuum state by the vacuum pump 40. During maintenance, the electron column 907 including the electron gun housing 60 is exposed to the atmosphere. In this case, the valve 61 is closed to seal the electron gun housing 60.

  The electron gun housing 60 is provided with a housing hole 62 at a position through which the irradiation beam IB passes. A valve 61 is provided below the electron gun housing 60. The valve 61 is provided with a valve hole 612 at a position corresponding to the electron gun housing 60. O-rings 613 and 614 are provided on the surface (upper surface) of the bulb 61 facing the electron gun housing 60.

  When the electron beam inspection apparatus 1000 is used, the valve 61 is positioned at the B position. At the B position, the valve hole 612 of the valve 61 and the housing hole 62 of the electron gun housing 60 coincide. In the A position, O-rings 613 and 614 respectively surround the housing holes 62 of the electron gun housing 60. When closing the electron gun housing 60 during maintenance, the valve 61 moves from the B position to the A position, and further moves upward from the A position, so that the O-rings 613 and 614 cause the electron gun housing 60 to move. The housing hole 62 is closed, and the electron gun housing 60 is sealed. In the movement of the valve 61 from the B position to the A position and from the A position to the B position, the movement in the horizontal direction and the movement in the vertical direction may be arbitrarily combined, or may be moved obliquely.

  As described above, in the present embodiment, the valve hole 612 that allows the irradiation beam IB to pass through the bulb 61 and the O-rings 613 and 614 for sealing the electron gun housing 60 are formed, and the bulb 61 is shifted laterally. Thus, the housing hole 62 of the valve 61 can be aligned with the housing hole 62 of the electron gun housing 60, and the O-rings 613 and 614 can surround the housing hole 62 of the electron gun housing 60. The irradiation beam IB from 60 can be passed, and the electron gun housing 60 can be sealed.

  FIG. 20 is a view showing another example of the valve mechanism of the present embodiment. The valve mechanism as described above may be provided at the lower end of the cylinder 50 as shown in FIG. A cylindrical hole 52 is provided at the lower end of the cylindrical body 50 at a position through which the irradiation beam IB passes. When the electron beam inspection apparatus 1000 is used, the valve 61 is positioned at the B position. At the B position, the cylinder hole 52 of the cylinder 50 and the valve hole 612 of the valve 61 coincide. In the A position, the O-rings 613 and 614 each surround the cylindrical hole 52 of the cylindrical body 50.

  When closing the electron gun housing 60 and the cylindrical body 50 during maintenance, the valve 61 moves from the B position to the A position and moves further upward from the A position, so that the O-rings 613 and 614 The cylinder hole 52 of the cylinder 50 is closed, and the space formed by the electron gun housing 60 and the cylinder 51 is sealed. In the movement of the valve 61 from the B position to the A position and from the A position to the B position, the movement in the horizontal direction and the movement in the vertical direction may be arbitrarily combined, or may be moved obliquely.

  Also in this embodiment, the valve 61 is formed with a valve hole 612 through which the irradiation beam IB passes and O-rings 613 and 614 for sealing the space formed by the electron gun housing 60 and the cylinder 50. 61 Since the valve hole 612 of the valve 61 can be aligned with the cylindrical hole 52 of the cylindrical body 50 and the O-rings 613 and 614 can surround the cylindrical hole 52 of the cylindrical body 50 by shifting in the horizontal direction. By operation, the irradiation beam IB from the electron gun housing 60 can be passed, or the space formed by the electron gun housing 60 and the cylindrical body 50 can be sealed.

7). Deflector The deflector deflects the irradiation beam IB emitted from the electron gun 30 for scanning. FIG. 21 is a diagram showing a configuration of a conventional deflector. The deflector 170 is composed of a single plate electrode, and a hole is formed in the electron line. The irradiation beam IB passing through the hole of the deflector 170 is changed by an angle corresponding to the magnitude of the voltage. An AC voltage of ± 60 V is applied to the deflector 170. By applying an AC voltage to the deflector 170, the irradiation beam IB is deflected according to the voltage amplitude, and the sample is scanned by the irradiation beam IB. According to this conventional configuration, there is a limit even when trying to increase the frequency of the AC voltage of ± 60 V applied to the deflector 170, thereby limiting the scanning frequency of the irradiation beam IB.

  FIG. 22 is a diagram illustrating a configuration of the deflector according to the present embodiment. The deflector 180 according to the present embodiment includes two plate-like electrodes 181 and 182. Each of the electrodes 181 and 182 has a hole in the electron line. The irradiation beam IB that has passed through the hole is deflected by an angle corresponding to the voltage applied to the electrodes 181 and 182. In the present embodiment, an AC voltage of ± 55 V is applied to the upper electrode 181, and an AC voltage of ± 5 V is applied to the lower electrode 182.

In the deflector 180, macro scanning is performed using the AC voltage applied to the upper electrode 181 and micro scanning is performed using the AC voltage applied to the lower electrode 182 with the above configuration. The frequency of the alternating voltage applied to the upper electrode 181 for performing macro scanning is greater than the frequency of the alternating voltage applied to the lower electrode 182 for performing micro scanning. By amplifying the voltage applied to the lower electrode 182 with respect to the irradiation beam IB deflected in a certain reference direction by the upper electrode 181, the irradiation beam IB is further deflected in a small range with respect to the reference direction. Then, the sample is scanned (micro scan). When main scanning and sub scanning which are possible within this range are performed, the voltage applied to the upper electrode 181 is changed and the reference direction is deflected (macro scanning).

  Then, by oscillating the voltage applied to the lower electrode 182 with the new reference direction as a reference, the irradiation beam IB is further deflected within a small range with the reference direction as a reference, and the sample is scanned (micro). scanning). In this way, by repeating the macro scan and the micro scan, when the scan within the range that can be deflected by the macro scan is completed, the stage moves and the micro scan and the macro scan similar to the above are performed for the next new region. Is done.

  In micro scanning, since the irradiation beam IB is deflected at a low voltage of ± 5 V, a high-frequency power source can be used, thereby increasing the scanning speed and shortening the specimen inspection time.

  In the above description, only one deflector 180 has been described. However, as described above, in the electron column 907 of the present embodiment, a plurality of electron beam irradiation detection systems are provided in one cylindrical body. A plurality of deflectors 180 are provided in the horizontal direction. At this time, a power source may be provided for each of the plurality of upper electrodes 181 and the plurality of lower electrodes 182, and a common power source may be used for the plurality of upper electrodes 181. In this case, an AC electrode offset from −4.5 V to 5.5 V is applied to the lower electrode 182. As described above, since the plurality of deflectors provided in parallel share the power source, not only the cost can be reduced, but also the electronic column 907 can be reduced in size.

  As described above, according to the present embodiment, the SEM structure, in particular, the components 10 to 19 and the spacers 20 to 28 are formed into a disk shape, so that assembly with high positional accuracy is possible, and the optical axis adjustment is easy. become. Therefore, maintenance of the inspection apparatus can be easily performed.

  In the present embodiment, a so-called single SEM has been described. However, a so-called multi-SEM in which a plurality of electron guns 30 are provided in the electron gun housing 60 may be used.

10 to 19: parts, 20 to 28: spacer, 30: electron gun, 50: cylinder

Claims (6)

An inspection apparatus for observing a sample by irradiating the sample placed on the stage with an electron beam and detecting the electron beam from the sample,
An electron gun for irradiating the electron beam;
A plurality of components including a deflector that performs alignment of the electron beam, an electrode that functions as a lens, and a detector that detects the electron beam from the sample;
A spacer provided between the plurality of components;
A cylindrical body in which the plurality of components and the spacer are housed, and
The plurality of parts and spacers are all in the shape of a disk having a hollow at the center, and are stacked so that the electron beam passes through the hollow.   The inspection apparatus according to claim 1, wherein each of the plurality of parts and the spacer is provided with a hole in addition to the cavity through which the electron beam passes.   The inspection apparatus according to claim 1, wherein each of the plurality of parts and the spacer is provided with a plurality of holes having different shapes in addition to a cavity through which the electron beam passes.   The inspection device according to claim 2 or 3, wherein the hole can be used to align the plurality of parts and the spacer, and becomes an exhaust hole when the cylinder is evacuated. The spacer includes a low resistance portion having a lower resistance than other portions,
The part of the low resistance part is connected to the part arranged on the upper side, and the other part of the low resistance part is connected to the part arranged on the lower side. The inspection device described in 1. The low resistance portion and at least a part of the surface of the component are each plated.
The inspection apparatus according to claim 5, wherein the low resistance portion and the component are connected via the plating.