JP2575750B2 - Electrostatic deflector and strobe electron beam device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] The present invention relates to an electrostatic deflector and its strobed electron beam device,
Particularly, regarding an electrostatic deflector that deflects an electron beam by a high-speed electric signal and a strobe electron beam device using the deflector, without directly deflecting the electron beam by an electric signal,
The electrostatic deflector is used to perform high-speed deflection with a sharp rise (several hundred picoseconds or less) and to pulse the electron beam into a strobe light by the high-speed deflection to measure a voltage of an object to be measured. Is an electrostatic deflector comprising first and second deflecting plates opposed to each other with the optical axis of the charged beam interposed therebetween, wherein the first deflecting plate applies a first DC voltage to the first deflecting plate.
An electrode part, a second electrode part for applying a second DC voltage, a third electrode part interposed between the first electrode part and the second electrode part, and a first electrode part. And a second gap between the second electrode section and the third electrode section, and a first gap between the first electrode section and the third electrode section, and a second gap between the second electrode section and the third electrode section. The strobe electron beam device includes at least an electron gun that irradiates an object to be measured with an electron beam and an electrostatic device that deflects the electron beam from the electron gun. Deflection means, a stop for restricting a passing range of an electron beam, a scanning means for scanning an electron beam or an object to be measured passing through the stop, and a secondary electron detecting means for detecting secondary electrons emitted from the object to be measured And signal processing means for processing a detection signal from the secondary electron detection means. The electro-deflecting means includes: an electrostatic deflector according to the present invention; a light source that emits a pulsed laser beam to the electrostatic deflector; and a DC power supply that supplies first and second DC voltages to the electrostatic deflector. 39.

[Industrial applications]

The present invention relates to an electrostatic deflector and a strobe electron beam device using the same, and more specifically,
An electrostatic deflector that deflects an electron beam by a high-speed electrical signal, and the electron beam is pulsed by the deflector, and an electron beam pulse is applied to the object to measure the voltage of the object to be measured and to measure the image. The present invention relates to an electron beam device for capturing.

[Conventional technology]

 5 and 6 are explanatory views according to a conventional example, and FIG. 5 (a) is a configuration diagram of an electrostatic deflector.

In FIG. 1, reference numeral 1 denotes a deflecting plate (about 1 cm.times.3 cm) for directly deflecting the electron beam 2 at a high speed by an electric signal, and is an electrode facing the optical axis 2a of the electron beam.
Reference numeral 2 denotes an electron beam emitted from an electron gun (not shown), and reference numeral 3 denotes a vacuum container. 2a is the optical axis of the electron beam.

Reference numeral 4 denotes a high-frequency terminal (trade name: SMA terminal) for guiding the deflection plate in the vacuum vessel to the outside of the vacuum. In addition, FIG.
5, which shows the two-dot chain line, the deflection signal (frequency, G Hz units) from the deflection circuit, not shown is a high-bandwidth transmission cable for transmitting the S ₁ to the deflection plate, for example, such as an impedance 50Ω coaxial cable is there. Reference numeral 6 indicated by a broken line in FIG. 3A denotes a terminating resistor (resistance value: 50Ω) for impedance matching.

FIG. 2B is a diagram showing a distributed constant circuit of the transmission cable 5, in which 11 is an electrostatic deflector, r is a resistor, l
Inductance, c is the capacitance, the V _s deflection voltage of the sending end, V _R denotes a deflection voltage of the receiving end. Note that the deflection signal that changes at a high speed is significantly affected by the frequency 5. For example, the reactance X _L = ωL is proportional to the frequency f, and the capacitance X _C = 1 / ωC is inversely proportional to the frequency f.

Figures (C1) and (C2) show the deflection voltage _S at the transmitting end and the deflection voltage at the receiving end with a sharp rise of several hundred picoseconds.
₇ is a voltage waveform showing _R. In the figure, the vertical axis represents voltages | _S |, | _R |, and the horizontal axis represents time t. In FIG. 3C, t ₁ is a difference between the rising voltage between the deflection voltage _S at the power transmission end of the deflection circuit and the deflection voltage _R at the power receiving end of the deflection plate 1, and is a delay time. Numeral 7 is a waveform distortion portion where the rise of the voltage and the rise are blunted.

FIG. 6A is a configuration diagram of a conventional strobe electron beam apparatus.

In the figure, reference numeral 10 denotes an object to be measured, which is a semiconductor integrated circuit such as an LSI. In addition, 11 is an electrostatic deflector, 2 is an electron beam, and 5 is a transmission cable. 8 is the electron beam 2
A scanning coil 9 for scanning the electron beam 2; a pulse generator 12 for supplying a rapidly changing deflection signal to the electrostatic deflector; an AP for restricting the passing range of the electron beam; Is a scan generator that supplies a scan signal to the scan coil, 14 is secondary electron detection means that detects secondary electrons 2b emitted from the measured object,
Reference numeral 15 denotes a signal processing unit, 16 denotes a voltage supply unit that supplies a test voltage to an LSI or the like to be measured in synchronization with a rise of a clock signal CLK, 17 denotes a monitor unit, 18 denotes a pulse generator 12, a scan generator 13, and a signal. Control means for controlling the processing means 15 and the like.
A strobed electron beam device that emits an electron beam pulse synchronized with the operation signal of I is constructed.

The operation is as follows. A test voltage is supplied to the LSI or the like of the device under test 10, and the metal wiring or the like is irradiated with the strobe pulse-shaped electron beam 2 in synchronization with the rising edge of the clock signal.
By detecting the secondary electrons 2b and performing the processing,
It measures the voltage of LSIs and displays the images.

FIG. 2B shows a deflection signal supplied to the electrostatic deflector 11 and shows an output waveform of the pulse generator and an input waveform of the electrostatic deflector 11. Incidentally, the input deflection voltage waveform of the electrostatic deflector 11, rises after a delay time t ₂ as compared with the output deflection voltage waveform of the pulse generator 12, its waveform dullness,
A waveform distortion portion 19 is generated.

[Problems to be solved by the invention]

By the way, according to the conventional electrostatic deflector 11, a deflection signal (frequency, in GHz) is supplied to a deflection plate constituting a counter electrode via a high-band coaxial cable to deflect the electron beam 2. In addition, according to the strobe electron beam apparatus using the electrostatic deflector 11, in order to form the electron beam 2 in a strobe pulse shape, a deflection signal (frequency, G) generated by the pulse generator 12 is synchronized with the clock signal CLK. (In Hz) is supplied to the electrostatic deflector 11 via a transmission cable 5 such as a high-band coaxial cable.

Therefore, due to the influence of the transmission cable 5, etc., Fig. 5 (C2)
6 (b), delay times t ₁ and t ₂ and waveform distortion portions 7 and 19 occur in the input deflection voltage waveform of the electrostatic deflector 11 as shown in FIG.

However, as operating characteristics such as LSI of the device under test 10 become faster, the deflection signal of the electron beam 2 for voltage measurement and image display is required to be increased in proportion to the speed. The electrostatic deflector 11 that deflects the electron beam 2 has a problem that it cannot be dealt with due to the influence of the frequency (in units of GHz) as described above.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the related art, and provides a high-speed deflection of a sharp rise (several hundred picoseconds or less) without directly deflecting an electron beam by an electric signal. An object of the present invention is to provide an electrostatic deflector capable of making an electron beam into a strobe pulse shape and measuring a voltage of an object to be measured, and a strobe electron beam apparatus using the same.

[Means for solving the problem]

As shown in FIG. 1, one embodiment of the electrostatic deflector of the present invention is an electrostatic deflector comprising first and second deflecting plates 21a and 21b opposed to each other across an optical axis 22a of a charged beam 22. A deflector, wherein the first deflection plate includes a first electrode unit 211 for applying a first DC voltage GND, a second electrode unit 214 for applying a second DC voltage E, A third electrode portion 212 interposed between the first electrode portion and the second electrode portion;
And a photoconductive crystal 213 provided in a first gap B between the first electrode section and the third electrode section and a second gap A between the second electrode section and the third electrode section. , Wherein the first gap and the second gap are configured to be selectively irradiated with light.

In the electrostatic deflector of the present invention, a first DC voltage is applied to the first electrode 211 and the second deflection plate of the first deflection plate, and the second electrode of the first deflection plate is applied. Second to part 214
And a first gap B of the first deflecting plate.
And irradiating the photoconductive crystal 213 in the second gap A with pulsed light alternately.

In the electrostatic deflector of the present invention, irradiation of the first light on the photoconductive crystal 213 in the first gap B of the first deflection plate and photoconduction in the second gap A of the first deflection plate are performed. Crystal 213
An arbitrary time difference Tw is set between the irradiation of the second light with respect to and the third electrode unit raised to a second DC voltage by the irradiation of the second light is irradiated with the first light, The third electrode unit is lowered to a first DC voltage, and subsequently the third electrode unit is raised to a second DC voltage by the irradiation of the second light, and is again irradiated with the first light. By third
The cycle of lowering the electrode unit to the first DC voltage is repeated, so that the third electrode unit becomes the first DC voltage by the time difference Tw between the irradiation of the first and second lights,
Light is irradiated alternately on the photoconductive crystals 213 in the first gap B and the second gap A.

As shown in FIG. 3, the strobe electron beam apparatus to which the electrostatic deflector of the present invention is applied has at least:
An electron gun 27 for irradiating the measurement target 26 with the electron beam 27a,
Electrostatic deflecting means 28 for deflecting the electron beam from the electron gun
A stop AP for limiting a passing range of the electron beam, a scanning unit 30 for scanning the electron beam or the object to be measured passing through the stop, and secondary electrons emitted from the object to be measured.
A secondary electron detecting means 31 for detecting 27b, and a signal processing means 32 for processing a detection signal from the secondary electron detecting means, the electrostatic deflecting means 28, the electrostatic deflector according to the present invention, A light source that emits a pulsed laser beam to the electrostatic deflector; and a DC power supply 39 that supplies first and second DC voltages to the electrostatic deflector. And achieve the above object.

[Action]

The operation of the electrostatic deflector of the present invention will be described. First, the charged beam 22 is passed through an electrostatic deflector where the first deflecting plate 21a and the second deflecting plate 21b face each other. Then, a first DC voltage (GND: 0 V) is applied to the second electrode plate 211 of the second deflection plate 21b and the first electrode plate 211 of the first deflection plate 21a, and the second electrode unit 2 of the first deflection plate 21a is applied.
A second DC voltage (E) is applied to 14.

In such a state, for example, the second deflection plate 21a
Light is applied to the photoconductive crystal 213 in the second gap A between the first electrode portion 214 and the third electrode portion 212. Then, this photoconductive crystal 2
13 conducts, the second electrode portion 214 and the third electrode portion 212
Are electrically connected, and these electrodes become one electrode plate. As a result, the second DC voltage (positive voltage) generates an electrostatic field between the first deflection plate 21a and the second deflection plate 21b, so that the charged beam 22 can be deflected to a certain position.

Further, light is removed from the photoconductive crystal 213, and this portion is turned off. Thereafter, the first gap B between the first electrode portion 211 and the third electrode portion 212 of the first deflection plate 21a is formed.
The photoconductive crystal 213 is irradiated with light. Then, since the photoconductive crystal 213 conducts, the first electrode portion 211 and the third electrode portion 212 are electrically connected, and these electrodes become one electrode plate. As a result, the static electric field generated between the first deflecting plate 21a and the second deflecting plate 21b disappears due to the first DC voltage (zero potential), so that the charged beam 22 is returned to the original position. Can be.

As described above, in the electrostatic deflector of the present invention, the second deflecting plate facing the first deflecting plate is formed by connecting three electrodes via the photoconductive crystal, and the first deflecting plate to which the DC voltage is applied is connected. Light is applied to the photoconductive crystal between the electrodes of the deflecting plate. For this reason,
By controlling the light irradiation timing, it is possible to generate a strobe-like electron beam with a sharp rise and an extremely short pulse width. Therefore, the charged beam can be deflected at a high speed.

Thus, if light is irradiated at a predetermined interval, it is possible to sufficiently cope with voltage measurement of an LSI operating at high speed. As a result, it is not necessary to directly supply a deflection signal (frequency, GHz unit) that rises as fast as several hundred picoseconds to the deflection plate as in the conventional example. Further, since a transmission cable as in the conventional example is not required, delay in rising of the deflection voltage waveform and waveform distortion due to the influence of the frequency can be eliminated. The charged beam is a negatively charged electron beam or a positively charged ion beam.

Next, the operation of the strobe electron beam device of the present invention will be described. For example, when acquiring a secondary electron image, first, in a state where the electron beam 27a is irradiated from the electron gun 27 onto the stop AP, the electrostatic deflecting unit 28 including the electrostatic deflector of the present invention is used.
Deflects the electron beam 27a.

At this time, light is applied to the photoconductive crystal 213 in the second gap A between the second electrode portion 214 and the third electrode portion 212 of the first deflection plate 21a. Then, since the photoconductive crystal 213 conducts, the second electrode portion 214 and the third electrode portion 212 are electrically connected, and these electrodes function as one electrode plate. As a result, the first voltage is applied to the first deflection plate by the second voltage (positive voltage).
Since an electrostatic field is generated between 21a and the second deflection plate 21b, the electron beam 27a can be deviated from the optical axis of the stop AP. As a result, the passage of the electron beam 27a through the stop AP is restricted.

Further, light is removed from the photoconductive crystal 213, and this portion is turned off. Thereafter, the first gap B between the first electrode portion 211 and the third electrode portion 212 of the first deflection plate 21a is formed.
The photoconductive crystal 213 is irradiated with light. Then, since the photoconductive crystal 213 conducts, the first electrode portion 211 and the third electrode portion 212 are electrically connected, and these electrodes function as one electrode plate. As a result, the electrostatic field generated between the first deflection plate 21a and the second deflection plate 21b disappears due to the first voltage (zero potential).
Optical axis.

Thereby, the electron beam 27a can be deflected at high speed on the stop AP. Note that the electron beam that has passed through the stop AP is applied to the object to be measured. Then, the secondary electrons emitted from the measured object are detected by the secondary electron detecting means. The detection signal from the secondary electron detection means is processed by the signal processing means. In addition, the scanning unit scans the electron beam 27a or the measured object 26 to move to the next image acquisition area.

As described above, according to the strobe electron beam apparatus of the present invention, since the electrostatic deflecting means is constituted by the electrostatic deflector according to the present invention, the electron beam 27a can be rapidly deflected on the stop AP.

Therefore, even if the operation of the LSI to be measured is accelerated, voltage measurement and image capture can be performed using a strobe-shaped electron beam with a sharp rise and an extremely short pulse width. As a result, it is not necessary to supply a deflection signal (frequency, GHz unit) that rises at high speed of several hundred picoseconds directly to the deflection plate as in the conventional example. And images can be captured.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of an electrostatic deflector according to an embodiment of the present invention, and FIG. 1A is a cross-sectional view thereof.

In the figure, reference numeral 21a denotes one of a pair of deflecting plates 21a and 21b facing each other including the optical axis of the charged beam 22. In addition,
The deflection plate 21a includes a first electrode portion 211, a second electrode portion 214, a third electrode portion (hereinafter, referred to as a deflection electrode) 212, and a photoconductive crystal 2
Consists of thirteen. A first DC voltage (G
ND; 0V), and a second DC voltage E is applied to the second electrode portion 214. The deflection electrode 212 is provided at a position sandwiched between the first electrode unit 211 and the second electrode unit 214. A first gap (hereinafter referred to as a photoconductive portion B) is provided between the first electrode portion 211 and the deflection electrode 212. A second gap (hereinafter referred to as a photoconductive portion A) is provided between the second electrode portion 214 and the deflection electrode 212.
The photoconductive crystal 213 is provided so as to connect the first gap B and the second gap A. In this embodiment, the photoconductive crystal 213
Are the first electrode unit 211, the deflection electrode 212, and the second electrode unit 21.
It has a substrate shape that backs 4. Reference numeral 23 denotes a vacuum container, which separates the vacuum portion from the outside of the vacuum by through terminals 24a and 24b. 22 is a charged beam,
An electron beam or a positive ion beam is used. 22a is the optical axis of the charged beam 22.

FIG. 2B is a perspective view of the electrostatic deflector, in which the vacuum vessel 23 and the through terminals 24a and 24b are omitted for convenience.

In the figure, a deflecting plate 21a is formed by further joining a photoconductive crystal 213 with electrodes 211 and 214 and a deflecting electrode (about 3 mm × 3 mm) 212. The photoconductive crystal 213
Is a chromium-doped GaAs crystal, and the photoconductive portion A
When the laser beam is not irradiated,
And a part of the photoconductive crystal which electrically insulates and deflects the electrode 212 from each other. The photoconductive portion B is a part of a photoconductive crystal that electrically insulates and separates the deflection electrode 212 from the electrode 211 when laser light is not irradiated.

21b is the other deflecting plate that faces the deflecting plate 21a and the optical axis 22a, and is constituted by a single metal plate. For example, a DC voltage E ₁ = approximately 5 V is applied to the electrode 214, and the deflection plate 21b is grounded.

Reference numeral 25a denotes a laser light source that irradiates the photoconductive portion A with the laser beam ₁₁ in a pulse shape, and reference numeral 25b denotes a laser light source that similarly irradiates the photoconductive portion B with the laser beam ₁₂ in a pulse shape. These constitute an electrostatic deflector.

FIG. 2 is an explanatory diagram of the operation of the electrostatic deflector according to the embodiment of the present invention.

FIGS. (A ₁ ) to (a ₄ ) show laser beams l ₁ and l applied to the photoconductive portions A and B of the deflecting plate 21 a to which a DC voltage (approximately E ₁ = 5 V) is applied to the electrode 214.
₂ shows an equivalent deflector when ₂ is irradiated.

In FIG. (A _1), by irradiating a laser beam l ₁ the photoconductive unit A, conducted through the electrode 214 a photoconductive portion A deflection electrode 212 transgressions photoconductive crystal 213, the DC voltage E = 5V is supplied to the deflection electrode 212.

FIG. ₂ (a ₂ ) shows that DC5V is applied to the deflection electrode 212 of the deflection plate 21a.
2 shows an equivalent deflector to which is applied. The charged beam 22 is deflected to a position off the optical axis.

In the same figure (a ₃ ), the laser beam l _{2 is applied} to the photoconductive portion B.
Irradiates the electrode 211 and the deflection electrode 212 through the photoconductive portion B of the photoconductive crystal 213, and the ground line GND =
0V is supplied to the deflection electrode 212.

FIG. (A ₄ ) shows that DC0V is applied to the deflection electrode 212 of the deflection plate 21a.
2 shows an equivalent deflector to which is applied. The charged beam 22 has returned to the optical axis.

FIG. 3B shows the irradiation timing of the laser beams l ₁ and l ₂ ,
The relationship between the deflection voltages of the deflection plates 21a and 21b is shown. In the figure, the vertical axis represents the light intensity I _a of the laser beam, indicate the I _b, the horizontal axis represents the time t. First, the photoconductive portion A is irradiated with the laser beam ₁₁ and the deflection voltage of the deflecting plate rises to DC 5 V. Next, the photoconductive portion B is irradiated with the laser beam ₁₂ and the deflection voltage of the deflecting plate rises to zero potential. Go down. By continuing this operation, the electron beam can be deflected. The laser light
The irradiation timing of l ₁ and l _{2 is} the timing of supplying the deflection voltage of the deflection plate.

By irradiating the deflecting plate 21a with the laser beams l ₁ and l ₂ in this manner, a DC voltage (approximately E ₁ = 5 V) is applied to the deflecting plate 21a to deflect the charged beam 22 such as an electron beam. Can be. Thus, it is not necessary to directly supply a deflection signal (in units of frequency G Hz) that rises at a high speed of several hundred picoseconds directly to the deflection plates 21a and 21b. For this reason, it is possible to eliminate the problem of generating a delay time and a waveform distortion part in the input deflection voltage waveform of the electrostatic deflector due to the influence of the frequency of the transmission cable or the like as in the related art.

FIG. 3 is a configuration diagram of a strobe electron beam apparatus according to an embodiment of the present invention.

In the figure, reference numeral 26 denotes an object to be measured in which a voltage distribution or wiring image of an LSI or the like incorporating an integrated circuit or the like is captured, and 27 denotes an electron gun for irradiating the object to be measured 26 with an electron beam 27a. Here, 27b is secondary electrons emitted from the measured object 26. Reference numeral 28 denotes an electrostatic deflector, and reference numerals 28a and 28b denote deflecting plates including the optical axis of the electron beam 27a. AP is an aperture that limits the passage range of the electron beam. Aperture AP
Is arranged above the scan coil 29, and the aperture of the aperture AP is aligned with the optical axis 22a of the electron beam. 29 is a scan coil for scanning the electron beam 27a, 30 is its scanning means, 31 is secondary electron detecting means for detecting secondary electrons emitted from the object 26 to be measured, 32 is its signal processing means, and 33 is a measuring voltage. A monitor means for displaying values and images, a voltage supply means 34 for supplying various test voltages necessary for measurement of the LSI and the like, and a control means 35 for controlling the scanning means 30, the signal processing means 32 and the like.

Up to now, the configuration is the same as the conventional configuration, but different in the following points. That is, one deflection plate 28a of the electrostatic deflector 28
To a DC power source 39 supplies a DC voltage, pulsed laser beam l _3, l ₄ optical pulse generating means 36 for generating the optical transmission means for guiding the laser beam l _3, l ₄ in the electron beam barrel 37a, 37b
When, and provided to the deflection plate 28a or 28b emitting portion 38a is irradiated with a laser beam l _3, l _4, and 38b. Note that CLK is a clock signal, which is output from the control means 35,
36 and the voltage supply means 34. These components constitute a strobe electron beam device.

FIG. 4 is a view for explaining the operation of the strobe electron beam apparatus according to the embodiment of the present invention, and FIG.
The relationship between the irradiation of l ₃ and l ₄ and the clock signal CLK is shown in a time chart.

In FIG, CLK is a clock signal, a laser beam l ₃ is irradiated to the photoconductive section A is first synchronized with the rise of the clock signal CLK, it raises the deflection voltage, synchronizing with the rising of the next clock signal CLK the laser beam l ₄ is irradiated to the photoconductive section B, the fall of the deflection voltage. Then following the clock signal CLK, the deflector 28a of the deflection voltage is irradiated likewise the laser beam l ₃ or l _4, supplied to 28b. This allows
By deflecting the electron beam 27a at high speed on the aperture AP, the strobe pulse-shaped electron beam 27a is
Can be irradiated. In this case, the electron beam
The pulse width of 27a is determined by the time difference Tw between the _two laser beams l ₁ and l ₂ .

FIG. 2B is a flowchart for explaining the operation of the strobe electron beam apparatus according to the embodiment of the present invention.

First, an electron beam 27a is emitted from the electron gun 27. Next, in synchronization with the rise of the clock signal CLK, the optical pulse generating means 36 irradiates the laser beam l ₃ , l ₄ to the photoconductive portion of the deflecting plate 28a or 28b, and supplies the DC voltage E to the deflecting electrode 212, Then, the deflection electrode 212 is returned to the ground potential (GND), and the electron beam 27a is electrostatically deflected. Next, the electron beam 27a is scanned over the LSI of the measured object 26 via the scanning means 30 and the scan coil 29. At this time, a test voltage is supplied to the LSI via the voltage supply means 34 in synchronization with the clock signal CLK.

Next, the secondary electrons 27 b emitted from the measured object 26 are detected via the secondary electron detection means 31. Further, the detection signal is processed through the signal processing means 32, and the control means 35,
Via the monitor means 33, the voltage distribution of the LSI, the wiring image thereof, and the like are displayed on the CRT device as images.

As described above, by using the electrostatic deflector of the present invention in a strobe electron beam apparatus, a direct deflection signal (frequency
(In GHz units) is not supplied to the deflecting plates 28a and 28b, so that it is possible to eliminate the problem of the related art and to perform accurate voltage measurement and image capture.

〔The invention's effect〕

As described above, in the electrostatic deflector of the present invention, the second deflecting plate facing the first deflecting plate is formed by connecting three electrodes via the photoconductive crystal and applying a DC voltage. 1
Light is applied to the photoconductive crystal between the electrodes of the deflecting plate. Therefore, by controlling the light irradiation timing, it is possible to generate a strobe-shaped electron beam having a sharp rising edge and an extremely short pulse width. Therefore, the charged beam can be deflected at a high speed.

Further, according to the strobe electron beam apparatus of the present invention, since the electrostatic deflecting means is constituted by the electrostatic deflector according to the present invention, it is possible to deflect the charged beam on the stop at a high speed.

Therefore, even if the operation of the LSI to be measured is accelerated, a voltage measurement and a secondary electron image can be obtained using a strobe-shaped electron beam having a sharp rise and an extremely short pulse width.

This eliminates the need to directly supply a deflection signal (frequency, in units of GHz) that rises as fast as several hundred picoseconds to the deflection plate, thereby improving voltage measurement accuracy and image acquisition accuracy.

Further, according to the present invention, the routing of the transmission cable,
Since no connector is required, the size of the polarizing plate can be reduced.
In addition, it is possible to eliminate the adverse effect of the frequency as in the related art.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electrostatic deflector according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the electrostatic deflector according to the embodiment of the present invention, and FIG. FIG. 4 is a diagram showing the operation of a strobe electron beam apparatus according to an embodiment of the present invention, FIG. 5 is an explanatory view of an electrostatic deflector according to a conventional example, and FIG. FIG. 2 is an explanatory view of a strobe electron beam device according to the first embodiment. (Explanation of reference numerals) 1,21a, 21b, 28a, 28b: Deflecting plate, 2, 22, 27a: Electron beam (charged beam), 2a, 22a: Optical axis of electron beam (optical axis of charged beam) , 2b, 27b ... secondary electrons, 3,23 ... vacuum vessel, 4 ... high-frequency terminal, 5 ... transmission cable, 6 ... terminating resistor, 7,19 ... waveform distortion part, 8,27 ... Electron gun, 9,29… Scan coil, 10,26… Target object, 11,28… Electrostatic deflector, 12… Pulse generator, 13,30 …… Scan generator (scanning means), 14, 31 secondary electron detection means 15, 32 signal processing means 16, 34 voltage supply means 17, 33 monitor means 18, 35 control means 24a, 24b through terminal , 25a, 25b ... laser light source, 211, 214 ... electrode, 212 ... deflection electrode, 213 ... photoconductive crystal, 36 ... light pulse generation means, 37a, 37b ... light transmission means, 38a, 38b ... light emission Part, 39 ... DC power supply, E ... direct Voltage (deflection voltage), l ₁ ~l ₄ ...... laser light, A, B ...... photoconductive unit, CLK ...... clock signal, the diaphragm AP .......

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihiro Ishizuka 1015 Uedanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Soichi Hama 1015 Kamikodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited ( 56) References JP-A-62-119845 (JP, A)

Claims (4)

(57) [Claims] 1. An electrostatic deflector comprising first and second deflection plates (21a, 21b) opposed to each other across an optical axis (22a) of a charged beam (22), wherein said first deflection A first electrode unit (211) for supplying a first DC voltage (GND);
And a second electrode unit (21) for supplying a second DC voltage (E).
4), a third electrode section (212) interposed between the first electrode section and the second electrode section, and the first electrode section;
From the photoconductive crystals (213) provided in the first gap (B) between the first electrode section and the third electrode section and the second gap (A) between the second electrode section and the third electrode section, respectively. An electrostatic deflector configured to selectively irradiate light to the first gap and the second gap. 2. A first electrode section of said first deflection plate.
And applying a first DC voltage (GND) to the second deflection plate,
The second electrode portion (214) of the first deflection plate has a second electrode.
And applying a pulsed light alternately to the photoconductive crystal (213) in the first gap (B) and the second gap (A) of the first deflection plate. The electrostatic deflector according to claim 1, characterized in that: 3. A method of irradiating a first light to a photoconductive crystal (213) in a first gap (B) of the first deflecting plate, the method comprising:
An arbitrary time difference (Tw) is set between the irradiation of the second light to the photoconductive crystal (213) in the second gap (A) of the deflecting plate, and the irradiation of the second light causes the second difference. By irradiating the third electrode portion raised to the DC voltage (E) with the first light, the third electrode portion is lowered to the first DC voltage (GND). The cycle of raising the third electrode unit to the second DC voltage by the irradiation and lowering the third electrode unit to the first DC voltage again by the irradiation of the first light is repeated. The photoconductive crystal in the first gap (B) and the second gap (A) is so arranged that the third electrode section has the first DC voltage by the time difference (Tw) between the irradiation of the second light. (213)
3. The electrostatic deflector according to claim 2, wherein light is emitted alternately. 4. An electron gun (27) for irradiating an object to be measured (26) with an electron beam (27a); electrostatic deflecting means (28) for deflecting an electron beam from the electron gun; An aperture (AP) for limiting a beam passing range, a scanning means (30) for scanning an electron beam or an object to be measured passing through the aperture, and detecting secondary electrons (27b) emitted from the object to be measured. A strobe electron beam device comprising: a secondary electron detecting means (31) for performing a detection signal from the secondary electron detecting means; and a signal processing means (32) for processing a detection signal from the secondary electron detecting means. A first deflecting plate (21b), and a plurality of electrode portions (211, 212, 214) provided at positions facing the first deflecting plate (21b) and a photoconductive crystal (213) connected between the electrode portions. Second deflection plate (21a) comprising:
A light source (25a, 25b) for irradiating pulsed light to the photoconductive crystal of the second deflection plate (21a); and a DC voltage supply to the first and second deflection plates (21a, 21b). And a direct-current power supply (39).