JP4235488B2 - Electron beam apparatus, pattern evaluation method using the apparatus, and device manufacturing method using the apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electron beam apparatus, a pattern evaluation method using the apparatus, and a device manufacturing method using the apparatus. In particular, in an electron beam apparatus suitable for performing defect inspection, line width measurement, defect review, or pattern potential measurement of a sample having a pattern with a minimum line width of 0.1 μm or less, preventing a decrease in the lifetime of the MCP Thus, the present invention relates to an apparatus capable of performing substrate evaluation with high throughput.
[0002]
[Prior art]
In a conventional electron beam apparatus using an electron beam, for example, a defect inspection apparatus or a CD length measuring apparatus, a sample surface is scanned with a multi-beam, and a secondary electron group emitted from the sample is amplified with an MCP, and then with a multi-anode. It is detected as a current, and analog information of this current is converted into digital information by an A / D converter, and a pattern is evaluated by an image forming circuit.
[0003]
An electron beam that irradiates a sample with a surface beam, expands secondary electrons with a mapping optical system, detects the image with an MCP, converts it into a light image with a scintillator, and evaluates the pattern via a TDI camera. A device has also been proposed.
[0004]
[Problems to be solved by the invention]
The MCP has a large number of channels, and the inner wall of such channels is coated with a material that assists the emission of secondary electrons. When secondary electrons hit the inner wall, gas is generated, and gas is also generated when the secondary electrons collide with the multi-anode. On the other hand, in the conventional electron beam apparatus as described above, the MCP and the multi-anode are arranged close to each other in order to prevent blurring of the electron beam output from the MCP to the multi-anode. Therefore, the gap formed between the MCP and the multi-anode becomes narrow, and it becomes difficult for the gas generated as described above to be discharged through the narrow gap. Therefore, such a gas stays between the MCP and the multi-anode, and even when a vacuum pump is used, it is outside the electron beam apparatus that is vacuumed by the vacuum pump from the local space between the MCP and the multi-anode. I couldn't vent the gas well. Since secondary electrons ionize the gas, ionized charged particles are generated. The positive ions, which are ionized charged particles, enter the MCP against the flow of secondary electrons, are multiplied inside the MCP, become a large number of ion beams near the front surface of the MCP, and are formed on the inner wall of the MCP channel. The applied secondary electron emission surface is scraped off, resulting in a problem of a reduction in lifespan that deteriorates sensitivity.
[0005]
Similarly, the MCP and the FOP caused the same problem because they were arranged close to each other at 0.8 mm or less so that the secondary electron image was not blurred.
[0006]
The present invention is intended to solve such problems. An electron beam apparatus capable of extending the lifetime of MCP and performing pattern evaluation with high throughput, a pattern evaluation method using the apparatus, and the apparatus are provided. It is to provide a device manufacturing method used.
[0007]
[Means for Solving the Problems]
The present invention separates an electron beam emitted from an electron gun by a multi-aperture, focuses it on a sample as a multi-beam, and scans it, and a spacing between a plurality of secondary electrons emitted from the sample surface. An electron beam apparatus comprising: a secondary optical system for enlarging the angle; and a detection device for detecting the secondary electrons output from the secondary optical system,
The detection device includes an MCP for multiplying and amplifying the secondary electrons output from the secondary optical system, and a multi-anode for detecting an electrical quantity of the secondary electrons output from the MCP. Including
The multi-anode has an escape passage formed in the multi-anode,
The MCP and the multi-anode are arranged to face each other so that a gap of a predetermined interval is formed between the MCP and the multi-anode, and the escape passage is formed between the gap and the outside of the gap. An electron beam apparatus that communicates with the outer space is provided.
[0008]
In the electron beam apparatus, the MCP is exposed to the multi-anode side through the escape passage formed in the multi-anode, and an aperture ratio when the MCP is viewed from the multi-anode is 0.5 to 0.9. It is preferable to form the escape passage so that
[0009]
The MCP is rectangular, the multi-anode is composed of a plurality of annular anodes, the plurality of anodes are spaced apart from each other, and at least the escape passage is formed between the plurality of anodes. Preferably, the plurality of anodes are insulated from each other.
[0010]
The anode is preferably arranged in a substantially straight line along the longitudinal direction of the MCP.
[0011]
The present invention also provides a primary optical system that separates an electron beam emitted from an electron gun by a multi-aperture, finely focuses and scans the sample as a multi-beam, and a plurality of secondary electron groups emitted from the sample surface. An electron beam apparatus comprising: a secondary optical system that expands the distance between each other; and a detection device that detects the secondary electrons output from the secondary optical system,
The detection device includes an MCP for multiplying the secondary electrons output from the secondary optical system, and a multi-anode for detecting an electrical quantity of the secondary electrons output from the MCP. ,
The multi-anode includes a plurality of anodes spaced apart from each other,
The present invention provides an electron beam apparatus in which the distance between the MCP and the multi-anode is separated so that the secondary electron group does not enter another anode adjacent to the target anode.
[0012]
In the electron beam apparatus, the distance is preferably at least 1 mm.
[0013]
Furthermore, the present invention enlarges the primary optical system that shapes the electron beam emitted from the thermionic emission electron gun into a rectangular shape and irradiates the sample surface, and the rectangular secondary electron image emitted from the sample surface. An electron beam apparatus comprising: a secondary optical system; and a detection device that detects the rectangular secondary electron image output from the secondary optical system,
The detection device includes an MCP for multiplying the secondary electron image output from the secondary optical system, and a converter for converting the secondary electron image output from the MCP into an image of light. Including
The converter includes a fiber optic plate and a scintillator provided on a surface of the fiber optic plate on the MCP side,
The exit surface of the MCP and the entrance surface of the scintillator are opposed to each other, and the exit surface of the MCP and the entrance surface of the scintillator are arranged such that a gap of a predetermined interval is formed between these surfaces. Has been
At least one of the exit surface of the MCP and the entrance surface of the scintillator is approximately the same size as the rectangular secondary electron image appearing in the direction intersecting the traveling direction of the secondary electron image. The present invention provides an electron beam apparatus having a rectangular shape.
[0014]
In the electron beam apparatus, the electron beam apparatus includes a planar first mesh and a planar second mesh,
The exit surface of the MCP and the entrance surface of the scintillator each have a peripheral edge,
The first mesh extends outward from the periphery of the exit surface of the MCP, and the second mesh extends outward from the periphery of the entrance surface of the scintillator. A wire device is provided.
[0015]
Further, the present invention is a pattern evaluation method using a multi-beam,
a. Irradiating the multi-aperture with an electron beam emitted from a thermionic emission electron gun; and
b. Reducing the electron beam emitted from the multi-aperture, focusing on the sample surface, and scanning the sample;
c. Passing and expanding an electron beam emitted from a plurality of scanning points on the sample surface through an objective lens;
d. Separating the secondary electron group that has passed through the objective lens of one stage or one stage from the primary optical system with an E × B separator;
e. After separating by the E × B separator, further expanding the distance between the secondary electron groups with at least one stage lens;
f. Independently detecting the expanded secondary electron group with an MCP and a multi-anode;
g. Converting the current flowing through the multi-anode into a voltage, amplifying it, and converting it into a digital signal with an A / D converter;
h. Forming a two-dimensional image from the digital signal,
Provided is a pattern evaluation method in which a relief passage penetrating toward the MCP side is formed in the multi-anode so that an aperture ratio when the MCP is viewed from the multi-anode is 0.5 to 0.9. is there.
[0016]
In the electron beam apparatus, the wafer may be evaluated using the pattern evaluation method described above.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of an electron beam apparatus according to the present invention will be described with reference to FIGS. FIG. 1 shows an electron beam apparatus according to the present embodiment. This electron beam apparatus forms a multi-beam from an electron beam emitted from an electron gun 12, and focuses and scans the multi-beam on a sample 28, and a secondary electron emitted from the sample surface. Are provided with a secondary optical system 40 that expands the distance between them and a detection device 50 that detects secondary electrons output from the secondary optical system.
[0018]
The primary optical system 10 includes a thermionic emission electron gun 12 that emits an electron beam, a multi-aperture plate 14 as a multi-aperture that separates the electron beam emitted from the thermionic emission electron gun 12 and forms a multi-beam, An NA aperture 18 disposed on the downstream side of the multi-aperture plate 14, and a condenser lens 16 disposed between the multi-aperture plate 14 and the NA aperture 18 to focus the multi-beam so as to form a crossover at the NA aperture 5; , A reduction lens 20 that reduces the multi-beams that have passed through the NA aperture 18, and a first objective lens 24 and a second objective lens 26 that further reduce the multi-beams reduced by the reduction lens 20. In this way, the primary optical system 10 forms a multi-beam from the electron beam emitted from the electron gun 12 and finely focuses the multi-beam on the sample 28. Further, the multi-beam is scanned on the sample 28 by a deflector (not shown) provided in the primary optical system 10. In FIG. 1, reference numeral 30 indicates an example of the trajectory of the primary electron beam.
[0019]
The secondary electrons emitted from the sample surface irradiated with the multi-beam are moved by the first objective lens 24 and the second objective lens 26 so as to pass through the secondary electron beam trajectory 32, for example, and the E × B separator. 22 is deflected in the direction of the secondary optical system 40.
[0020]
The secondary optical system 40 enlarges the interval between secondary electrons deflected by the E × B separator 22 and periodically deflects secondary electrons passing through the magnification lens 42 with a small amplitude. And a deflector 44. Since the deflector 44 periodically deflects the secondary electrons with a small amplitude in this way, the secondary electrons periodically move on the MCP 52 provided in the detection device 50. As a result, the secondary electrons The electrons do not always enter the same location of the MCP 52.
[0021]
In the present embodiment, it has been described that the E × B separator 22 is not included in the primary optical system 10 or the secondary optical system 40, but can be regarded as included in the primary optical system 10. However, it can also be regarded as being included in the secondary optical system 40. Further, it can be regarded as being included in both the primary optical system 10 and the secondary optical system 40.
[0022]
The detection device 50 includes an MCP 52 for multiplying secondary electrons output from the secondary optical system 40, and a multi-anode 54 for detecting the electrical quantity of secondary electrons output from the MCP 52. . The multi-anode 54 is disposed on the downstream side of the MCP 52 and is supported by an insulating substrate 66 disposed around the MCP 52.
[0023]
The MCP 52 (that is, the microchannel plate) has a rectangular shape, in particular, a rectangular shape in this embodiment, and includes an incident surface 53 on which a secondary electron beam is incident and an emission surface 59 on which the secondary electron beam is emitted. I have. The MCP 52 includes a large number of channels (through holes) 72, and the channel 72 has a structure distributed two-dimensionally along a plane parallel to the incident surface and the exit surface of the secondary electron beam. The MCP 52 is an electron multiplier that generates a large amount of secondary electrons when electrons enter each channel 72 and collide with its inner wall. Each channel 72 acts as an independent electron multiplier. When electrons are applied to the MCP 52 from the low potential side surface of the MCP 52 in a state where a voltage is applied between the electrodes on both sides of the MCP 52, the electrons incident on each channel 72 hit the inner surface of each channel. More secondary electrons are emitted. The secondary electrons are accelerated by the voltage applied between both surfaces of the MCP 52 and are emitted from the opening portions of the respective channels opened on the high potential side surface of the MCP 52. The electron multiplication factor (= number of emitted electrons / number of incident electrons) of the MCP 52 can be adjusted by changing the voltage applied between the electrodes on both sides of the MCP 52. In this embodiment, two MCPs 52 are overlapped so that each channel 72 is connected as one passage.
[0024]
The insulating substrate 66 has a rectangular shape larger than the rectangular MCP 52 and has a rectangular opening 68 slightly larger than the MCP 52. Two linked MCPs 52 are inserted into the opening 68. The exit surface 59 of the MCP 52 is positioned in the opening 68 so that a step is formed between the exit surface 59 of the MCP 52 and the downstream side surface 67 of the insulating substrate 66. As described above, since the rectangular opening 68 slightly larger than the MCP 52 is formed in the insulating substrate 66, the secondary electrons emitted from the MCP 52 enter the multi-anode 54 through the opening 68. Therefore, by providing the insulating substrate 66, the flow of secondary electrons between the MCP 52 and the multi-anode 54 is not hindered.
[0025]
The multi-anode 54 is composed of a plurality of anodes 56. Each anode 56 includes an annular anode electrode 57 and a shaft 58 extending from the anode electrode 57. The respective anodes 56 are spaced apart from each other, whereby a space 60 is formed between the respective anodes 56. The annular anode electrode 57 is provided with an opening 62. A space 60 between the anodes 56 and the opening 62 of the anode electrode 57 constitute an escape passage 64. The shaft 58 has a base end portion 58 a, and the base end portion 58 a is screwed to the downstream side surface 67 of the insulating substrate 66 with a screw 61. In this way, the anode 56 extends from the downstream side surface 67 of the insulating substrate 66 in parallel to the downstream side surface 67 toward the opening 68 of the insulating substrate 66. As described above, since the step is formed between the downstream side surface 67 of the insulating substrate 66 and the exit surface 59 of the MCP 52, the anode 56 is separated from the exit surface 59 of the MCP 52 by a distance corresponding to the step. Is positioned. In this way, the MCP 52 and the multi-anode 54 are arranged to face each other so that a gap 55 having a predetermined interval is formed between the MCP 52 and the multi-anode 54. The escape passage 64 communicates the 55 gap with an outer space outside the gap 55 (in this embodiment, a space formed on the downstream side of the multi-anode 54).
[0026]
In addition, as shown in FIG. 2, the anodes 56 adjacent to each other are fixed to the right side of the insulating substrate and the other is fixed to the left side of the insulating substrate. As a result, the anodes 56 are arranged to be staggered as a whole. ing. However, all the anodes may be fixed on one side of the insulating substrate.
[0027]
The annular anode electrode 57 is aligned substantially along a straight line along the longitudinal direction of the MCP 52 and is disposed at a position corresponding to a position where secondary electrons discharged from the MCP 52 form an image.
[0028]
The insulating substrate 66 is coated with a metal so that the downstream side surface 67 is not charged. However, the insulator 66a constituting the insulating substrate is exposed only in the vicinity of the portion where the anode 56 is fixed to the insulating substrate 66 so that the anodes 56 are insulated from each other.
[0029]
The MCP 52 is exposed to the multi-anode side via a relief passage 64 formed in the multi-anode 54. The escape passage 64 is an opening ratio when the MCP 52 is viewed from the multi-anode 54, that is, an area where the MCP 52 is exposed. Is divided by MCP52 to be 0.5 to 0.9.
[0030]
The predetermined interval between the MCP 52 and the multi-anode 54, that is, the interval of the gap 55 is at least 1 mm or more so that the secondary electrons do not enter the other anode 56 adjacent to the target anode. 2 mm.
[0031]
The secondary electrons output from the secondary optical system 40 are imaged on the MCP 52 and collide with the inner wall of the channel 72 of the MCP 52 to generate a large amount of secondary electrons. The amplified secondary electrons are It collides with the anode electrode 57 of. As described above, since the deflector 44 periodically deflects the secondary electrons with a small amplitude, the secondary electrons periodically move on the MCP 52. As a result, the secondary electrons are located at the same location on the MCP 52. Is not always incident. This prevents the life of the MCP 52 from being reduced. Since this deflection is in a direction perpendicular to the direction in which the multi-anodes 54 are arranged (that is, the longitudinal direction of the anodes 56), secondary electrons enter the other anodes 56 adjacent to the target anode 56 and interfere with each other. There is no. The secondary electrons that collide with the anode 54 flow along the anode 54 as a current and are detected as an electrical quantity.
[0032]
The current flowing through the multi-anode 54 is output to the resistor 102 connected to the multi-anode 54 via the conductive wire 99. The output device 100 is connected to the resistor 102. The output device 100 detects an analog amount voltage generated in the resistor 102 when a current from the multi-anode 54 flows, converts the analog amount voltage into a digital amount voltage, and the A / D converter 104. And an image forming circuit 106 for forming an image of the sample based on the output analog voltage.
[0033]
The A / D converter 104 and the image forming circuit 106 are disposed outside the electron beam apparatus, that is, in the atmosphere, and the primary optical system 10, the secondary optical system 40, and the detection apparatus 50 are in a vacuum state. It is arrange | positioned in the electron beam apparatus which becomes. In FIG. 1, a dotted line 108 indicates a vacuum wall of the electron beam apparatus.
[0034]
Gas is generated when the secondary electrons collide with the inner wall of the channel 72 of the MCP 52 and when the secondary electrons collide with the anode 56. Most of the gas is quickly discharged from the gap 55 at a predetermined interval to the space outside the gap 55 through the above-described escape passage 64.
[0035]
In the conventional electron beam apparatus, the multi-anode has a plate shape, and the plate-shaped multi-anode and the MCP are close to each other in order to prevent blurring of the electron beam output from the MCP to the multi-anode. Was arranged. For this reason, the gap of a predetermined interval formed between the MCP and the multi-anode is narrowed and exhausted through only the narrow gap, so that it is difficult to quickly exhaust the gas generated as described above. It was. Therefore, such gas stays between the MCP and the multi-anode, and even when a vacuum pump is used, the gas is not released from the local space to the outside of the electron beam apparatus that is in a vacuum state by the vacuum pump. It did n’t work. Since secondary electrons ionize the gas, ionized charged particles are generated. The positive ions, which are ionized charged particles, enter the MCP against the flow of secondary electrons, are multiplied inside the MCP, become a large number of ion beams near the front surface of the MCP, and are formed on the inner wall of the MCP channel. The applied secondary electron emission surface is scraped off, resulting in a problem of a reduction in lifespan that deteriorates sensitivity. On the other hand, in the present embodiment, most of the generated gas is quickly discharged from the gap 55 to the space outside the gap 55 through the above-described escape passage 64, so that the gas is ionized. As a result, the sensitivity of the MCP 52 can be maintained over a long period of time.
[0036]
Next, a second embodiment of the electron beam apparatus according to the present invention will be described with reference to FIGS. FIG. 4 shows an electron beam apparatus according to the present embodiment. The electron beam apparatus includes a primary optical system 200 that shapes an electron beam emitted from a thermionic emission electron gun 202 into a rectangular shape and irradiates the sample surface 216, and a rectangular secondary electron emitted from the sample surface 216. A secondary optical system 300 for enlarging an image and a detection device 400 for detecting the rectangular secondary electron image output from the secondary optical system are provided.
[0037]
The primary optical system 200 includes a shaping aperture (not shown) for shaping an electron beam emitted from the electron gun 202 into a desired rectangular beam, and an axis target for correcting the optical axis of the rectangular beam so as to be along the optical axis 208 of the primary optical system. Lenses 204 and 206, a first objective lens 214 that reduces the rectangular beam deflected toward the sample surface 216 by the E × B separator 210, and a second objective lens 216 are provided. In this way, in the primary optical system 200, the electron beam emitted from the electron gun 202 has a rectangular shape, and the sample surface 216 is irradiated with a rectangular beam. In addition, a rectangular beam is scanned on the sample surface 216 by a deflector (not shown) provided in the primary optical system.
[0038]
Secondary electrons emitted from the sample surface 216 irradiated with the rectangular beam form an enlarged image on the deflection main surface of the E × B separator 210 by the objective lenses 214 and 212.
[0039]
The secondary optical system 300 includes magnifying lenses 302, 304, and 306 that further magnify the magnified image of the secondary electrons formed on the deflection main surface of the E × B separator 210, and the magnifying lens of the secondary electron image. And a deflector (not shown) that always forms an image on the MCP 402 downstream of 306.
[0040]
In the present embodiment, the E × B separator 210 has been described as not included in the primary optical system 200 or the secondary optical system 300, but may be regarded as included in the primary optical system 200. However, it can also be regarded as being included in the secondary optical system 300. Further, it can be regarded as being included in both the primary optical system 200 and the secondary optical system 300.
[0041]
The detection apparatus 400 includes an MCP 402 for multiplying secondary electrons output from the secondary optical system 300, a converter 403 for converting an image of secondary electrons output from the MCP 402 into an optical image, A planar first mesh 408, a planar second mesh 410, and a planar third mesh 406 for making the electric field between the transducer 403 uniform are included. In the present embodiment, the first mesh 408, the second mesh 410, and the third mesh 406 are provided in the detection apparatus 400. However, the first mesh 408, the second mesh 410, The third mesh 406 is not necessarily provided.
[0042]
The MCP 402 has the same structure and function as described in the first embodiment. The MCP 402 has an incident surface on which secondary electrons are incident and an output surface 412 on which secondary electrons are emitted.
[0043]
The converter 403 is disposed on the downstream side of the MCP 402. The converter 403 includes a scintillator 404 provided opposite to the MCP, and an FOP (that is, a fiber optic plate) 405 that is in contact with the scintillator 404 and extends toward a surface from which secondary electrons are emitted. ing. In the present embodiment, the scintillator 404 is configured by coating the surface of the FOP 405 facing the MCP, that is, the surface on the MCP side. Alternatively, a plate-like scintillator may be attached to the MCP facing surface of FOP405. In addition, the scintillator 404 has an incident surface 414 on which secondary electrons are incident and is disposed to face the emission surface 412 of the MCP 402. Thus, the exit surface 412 of the MCP 402 and the entrance surface 414 of the scintillator 404 are opposed to each other, and a gap 416 with a predetermined interval is formed between the exit surface 412 of the MCP 402 and the entrance surface 414 of the scintillator 404. So that it is arranged. Further, the exit surface 412 of the MCP 402 has a peripheral portion 420, and the incident surface 414 of the scintillator 404 has a peripheral portion 418.
[0044]
The first mesh 408 extends outward from the peripheral edge 420 of the exit surface 412 of the MCP 402, and the second mesh 410 extends outward from the peripheral edge 418 of the incident surface 414 of the scintillator 404. . The third mesh 406 extends outward from the secondary electron incident surface of the MCP 402. Each planar mesh is made of a conductor and has a mesh structure, so that gas can pass therethrough.
[0045]
The secondary electron image output from the MCP 402 is converted into a light image by the scintillator 404, guided by the FOP 405, and emitted downstream. The distance between the MCP 402 and the scintillator 404 must be 0.8 mm or less so that the secondary electron image amplified by the MCP 402 and formed on the scintillator 404 is not blurred. In the present embodiment, each of the MCP 402, the scintillator 404, and the FOP 405 has a rectangular shape that appears in the direction intersecting the direction in which the secondary electrons travel (that is, the optical axis direction or the axial direction of the secondary electrons). It is formed in a rectangular size that is approximately the same size as the image of the secondary electron beam. A rectangular secondary electron beam image 413 as shown in FIG. 5 is projected on the emission surface 412 of the MCP 402. The secondary electron beam image 413 is output via the emission surface 412 and is incident on the incident surface 414 of the scintillator 404. The MCP 402 is approximately the same size as the secondary electron beam image 413 in the direction intersecting the direction in which the secondary electrons travel (the horizontal direction in the figure when viewed in FIG. 4 and the vertical direction in the figure when viewed in FIG. 5). It is formed in the size of the rectangular shape. Similarly, both the scintillator 404 and the FOP 405 are formed in a rectangular shape having the same size as that of the secondary electron beam image 413. At least one of the facing surface 412 of the MCP and the facing surface 414 of the scintillator intersects with the traveling direction of the secondary electron image, and is almost the same size as the rectangular secondary electron image shown there. What is necessary is just to be formed in the dimension of the rectangular shape.
[0046]
The output device 500 includes a relay lens 502 and a TDI camera 504. The relay lens 502 forms a secondary electron image output from the FOP 405 on the TDI camera 504, and the TDI camera 504 forms this image. The secondary electron image is converted into an electronic signal.
[0047]
The output device 500 further includes a control device 520 connected to the TDI camera 504 so that data communication is possible. As shown in FIG. 4, the control device 520 can be configured by a general-purpose personal computer or the like as an example. The computer includes a control unit 522 that executes various controls and arithmetic processes according to a predetermined program, a storage device 524 that stores the predetermined program, and a CRT monitor that displays processing results, a secondary electronic image 526, and the like. 528 and an input unit 530 such as a keyboard and a mouse for an operator to input commands. Of course, the control device 520 may be configured from hardware dedicated to the defect inspection apparatus, a workstation, or the like.
[0048]
In the conventional electron beam apparatus, the MCP has a cylindrical shape and the like, includes a channel and an outer ring that are not used, and the scintillator also includes a portion that is not used, and a direction intersecting the optical axis direction. Was getting longer. Further, as described above, the distance between the MCP and the scintillator is 0.8 mm or less. Therefore, the gap formed between the MCP and the scintillator has a long length in the direction intersecting the optical axis direction and a narrow width in the optical axis direction. Since the gas generated for the same reason as in the first embodiment was discharged through a gap having a long distance and a narrow width in the crossing direction, it was difficult to quickly discharge the generated gas. . For this reason, the same problem as the decrease in the service life of the MCP is caused as in the first embodiment. On the other hand, in this embodiment, the electron beam is formed in a rectangular shape, and an image is always formed on the channel defined by the MCP by the deflector. As a result, channels and outer rings not used by the MCP and portions not used by the scintillator can be deleted, and the MCP and scintillator are rectangles having approximately the same size as the image of the rectangular secondary electron beam reflected therein. The dimensions of the shape. For this reason, the gas that has remained in the narrow gap between the MCP and the scintillator as in the prior art has a shorter distance from the gap 416 to the outer space outside the gap 416 compared to the prior art. The gas is not quickly discharged into the outer space outside 416 and the gas is not ionized. As a result, the sensitivity of the MCP 402 can be maintained over a long period of time.
[0049]
In addition, as described above, since at least one of the MCP 402 and the scintillator 404 is formed to have a rectangular shape that is approximately the same size as the image of the rectangular secondary electron beam reflected on the MCP 402 and the scintillator 404, Is disturbed around the edges of the MCP 402 and the scintillator 404, and the equipotential lines at the locations are bent. When the beam passes through the portion where the electric field is disturbed in this manner, the flow of the beam is distorted, and the secondary electron imaging in the scintillator 404 is deviated from the image discharged from the sample surface. Therefore, in the present embodiment, the first mesh 408 and the second mesh 410 made of a conductor are provided to make the electric field between the MCP 402 and the scintillator 404 uniform. As these meshes extend outward from the outer peripheral surfaces 420 and 418 of the MCP 402 and scintillator 404 as shown in FIG. 5, the flow of secondary electrons between the MCP 402 and the scintillator 404 is not hindered. Absent. Moreover, since it has a mesh-like structure, the gas flow is not hindered. Depending on the type of electrostatic lens used for the magnifying lens 306, a planar third mesh 406 may be provided to help make the electric field between the MCP 402 and the scintillator 404 uniform.
[0050]
Next, an embodiment of a method for manufacturing a semiconductor device by the electron beam apparatus shown in the above embodiment will be described with reference to FIGS.
[0051]
FIG. 6 is a flowchart showing an embodiment of a semiconductor device manufacturing method according to the present invention. The manufacturing process of this embodiment includes the following main processes.
(1) Wafer manufacturing process for manufacturing a wafer (or wafer preparation process for preparing a wafer) (step 600)
(2) Mask manufacturing process for manufacturing a mask used for exposure (or mask preparation process for preparing a mask) (step 602)
(3) Wafer processing process for performing necessary processing on the wafer (step 604)
(4) Chip assembly process for cutting out chips formed on the wafer one by one and making them operable (step 606)
(5) Chip inspection process for inspecting the assembled chip (step 608)
Each of the main processes described above further includes several sub-processes.
[0052]
Among these main processes, the wafer processing process (3) has a decisive influence on the performance of the semiconductor device. In this process, designed circuit patterns are sequentially stacked on a wafer to form a large number of chips that operate as memories and MPUs. This wafer processing process includes the following processes.
(A) A thin film forming process for forming a dielectric thin film to be an insulating layer, a wiring portion, or a metal thin film for forming an electrode portion (using CVD, sputtering, etc.)
(B) Oxidation process for oxidizing this thin film layer and wafer substrate
(C) A lithography process for forming a resist pattern using a mask (reticle) to selectively process a thin film layer, a wafer substrate, or the like.
(D) An etching process for processing a thin film layer or a substrate according to a resist pattern (for example, using a dry etching technique)
(E) Ion / impurity implantation diffusion process
(F) Resist stripping process
(G) Inspecting the processed wafer
The wafer processing process is repeated as many times as necessary to manufacture a semiconductor device that operates as designed.
[0053]
FIG. 7 is a flowchart showing a lithography process which forms the core of the wafer processing process. This lithography process includes the following steps.
(A) A resist coating process for coating a resist on the wafer on which the circuit pattern is formed in the previous process (step 700).
(B) Step of exposing the resist (Step 702)
(C) Development process of developing the exposed resist to obtain a resist pattern (step 704)
(D) An annealing process for stabilizing the developed resist pattern (step 706)
The above semiconductor device manufacturing process, wafer processing process, and lithography process are well known and need no further explanation.
[0054]
When the defect inspection method and the defect inspection apparatus according to the present invention are used in the inspection process of (G) above, even a semiconductor device having a fine pattern can be inspected with high throughput. It becomes possible to prevent shipment of defective products.
[0055]
The above is each embodiment of the present invention, but the present invention is not limited to the above embodiment.
[0056]
【The invention's effect】
According to the present invention, the escape passage is formed in the multi-anode, and the escape passage communicates the gap between the MCP and the multi-anode with the outer space outside the gap. Gas that remained in the gap between the multi-anode and the multi-anode became easy to be discharged through the escape passage. Therefore, the gas remaining in the gap is ionized into secondary electrons, and the ion beam formed by the ionized charged particles is less likely to cause a problem of damaging the inner wall of the MCP channel.
[0057]
Further, according to the present invention, at least one of the opposing surface of the MCP and the opposing surface of the scintillator is a rectangular secondary electron image reflected in a direction intersecting the direction in which the secondary electron image travels. It was formed to have a rectangular shape with approximately the same size. As a result, the gas remaining in the narrow gap between the MCP and the transducer as in the prior art has a shorter distance from the gap to the outer space outside the gap, compared to the prior art. It became easy to be discharged.
[Brief description of the drawings]
FIG. 1 is a schematic view of an electron beam apparatus according to a first embodiment of the present invention.
FIG. 2 is an enlarged top view of the electron beam apparatus detector shown in FIG. 1 as viewed from the multi-anode side.
FIG. 3 is a side view of FIG. 2;
FIG. 4 is a schematic view of an electron beam apparatus according to a second embodiment of the present invention.
FIG. 5 is a top view of the MCP of the electron beam apparatus shown in FIG. 4 as viewed from the converter side.
FIG. 6 is a flowchart showing an embodiment of a method for manufacturing a semiconductor device.
FIG. 7 is a flowchart showing a lithography process in the method for manufacturing the semiconductor device of FIG. 6;
[Explanation of symbols]
10 Primary optics 12 Thermionic emission electron gun
14 Multi-aperture plate 16 Condenser lens
18 NA aperture 20 Reduction lens
22 E × B separator 24 First objective lens
26 Second objective lens 28 Sample
30 Primary electron beam orbit 32 Secondary electron beam orbit
40 Secondary optical system 42 Magnifying lens
44 Deflector 46 Secondary optical system optical axis
50 detector 52 MCP
53 MCP entrance surface 54 Multi-anode
55 Gap 56 Anode
57 Anode electrode 58 Shaft
58a Extension end of shaft 58 59 MCP exit surface
60 space 61 screw
62 Opening 64 Escape passage
66 Insulating substrate 66a Insulator
67 Downstream side of insulating substrate 68 Opening
100 output device 102 resistance
104 A / D converter 106 Image forming circuit
200 Primary optical system 202 Electron gun
204 Axis target lens 206 Axis target lens
208 Optical axis of primary optical system 210 E × B separator
212 First objective lens 214 Second objective lens
216 Sample surface 300 Secondary optical system
302 Magnifying lens 304 Magnifying lens
306 Magnifying lens 400 Detector
402 MCP 403 Converter
404 scintillator 405 FOP
406 Third mesh 408 First mesh
410 Second mesh 412 Output surface
414 Incident surface 416 Gap
418 Scintillator perimeter 420 MCP perimeter
500 Output device 502 Relay lens
504 TDI camera 520 controller
522 Control unit 524 Storage device
526 Secondary electron image 528 CRT monitor
530 input section

Claims (5)

A primary optical system that separates the electron beam emitted from the electron gun with a multi-aperture, focuses it on the sample as a multi-beam, and scans it, and expands the interval between a plurality of secondary electrons emitted from the sample surface. An electron beam apparatus comprising: a secondary optical system; and a detection device that detects the secondary electrons output from the secondary optical system,
The detection device includes an MCP for multiplying the secondary electrons output from the secondary optical system, and a multi-anode for detecting an electrical quantity of the secondary electrons output from the MCP. ,
The multi-anode includes a plurality of anodes spaced apart from each other, an escape passage is formed between the plurality of anodes, and the plurality of anodes are insulated from each other,
The MCP and the multi-anode are arranged to face each other so that a gap of a predetermined interval is formed between the MCP and the multi-anode, and the escape passage is formed between the gap and the outside of the gap. and communicating the outer space in,
The MCP is exposed to the multi-anode side through the escape passage formed in the multi-anode so that an aperture ratio when the MCP is viewed from the multi-anode is 0.5 to 0.9. The escape passage is formed,
Thereby, the gas generated between the MCP and the multi-anode is quickly discharged from the gap through the escape passage to an outer space outside the gap. . The electron beam apparatus according to claim 1,
The MCP has a rectangular shape,
Each of the plurality of anodes has an annular shape,
2. An electron beam apparatus according to claim 1, wherein an escape passage as an opening is provided in the annular anode . The electron beam apparatus according to claim 2 ,
2. The electron beam apparatus according to claim 1, wherein the plurality of anodes are arranged in a substantially straight line along the longitudinal direction of the MCP. A pattern evaluation method using a multi-beam,
a. Irradiating the multi-aperture with an electron beam emitted from a thermionic emission electron gun; and
b. Reducing the electron beam emitted from the multi-aperture, focusing on the sample surface, and scanning the sample;
c. Passing and expanding an electron beam emitted from a plurality of scanning points on the sample surface through an objective lens;
d. Separating the secondary electron group that has passed through the objective lens of one stage or one stage from the primary optical system with an E × B separator;
e. After separating by the E × B separator, further expanding the distance between the secondary electron groups with at least one stage lens;
f. Independently detecting the expanded secondary electron group with an MCP and a multi-anode;
g. Converting the current flowing through the multi-anode into a voltage, amplifying it, and converting it into a digital signal with an A / D converter;
h. Forming a two-dimensional image from the digital signal,
The multi-anode includes a plurality of anodes spaced apart from each other, an escape passage is formed between the plurality of anodes, and the plurality of anodes are insulated from each other,
The MCP and the multi-anode are arranged to face each other so that a gap of a predetermined interval is formed between the MCP and the multi-anode, and the escape passage is formed between the gap and the outside of the gap. and communicating the outer space in,
The MCP is exposed to the multi-anode side through the escape passage formed in the multi-anode so that an aperture ratio when the MCP is viewed from the multi-anode is 0.5 to 0.9. The escape passage is formed in
The pattern evaluation method characterized in that the gas generated between the MCP and the multi-anode is quickly discharged from the gap through the escape passage to an outer space outside the gap . Electron beam apparatus according to any one of claims 1 to 3, or, by using a pattern evaluation method described in claim 4, device manufacturing method, characterized in that the evaluation of the wafer.

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