JPS5965783A - Measuring device for picture due to particle beam - Google Patents

Abstract

PURPOSE:To measure 2-dimensional pictures, by using a microchannel plate which redoubles a signal electron up to a number approximate to a fixed level in addition to a 2-dimensional semiconductor position detector and setting the lower limit to the waveheight of a detection pulse to detect the generating positions of electrons and to eliminate the noise component produced by the heat noises. CONSTITUTION:The picture of electrons transmitted through a sample 1 is formed. A microchannel plate 33 contains many through holes (channels), and the electron is discharged from an output surface while keeping the information on its incident position. The channel is curved with the channel length of >=100 times as much as the caliber so as to set the redoubling factor approximate to a fixed level as close as possible. In such a constitution, a pulse waveheight selector 5 can discriminate the electrons sent from the plate 33 due to a single electron from the noises which are generated from the inner surface of channels due to heat.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides images that are caused by particle beams whose inputs, such as charged particles such as electrons and ions, and neutrons, which are the basis of image composition, are below the level that can be resolved in time within a two-dimensional resolution unit. This invention relates to an image measuring device for measuring particle beams.

As devices for detecting a particle beam image formed by the distribution of incident particles, there are known devices that use photographic film and devices that use an imaging tube or the like to image the light emitted from a fluorescent surface excited by a particle beam.

If there is a sufficient particle dose, a particle beam image can be detected by each of the above devices, but if a sufficient particle dose is not obtained, the signal-to-noise ratio of the image obtained by n1 measurement is small and good measurement is performed. I can't get any results.

The latter is a device that images the luminescence of a fluorescent surface excited by a particle beam, and if the particle beam is received for a long time in order to obtain a sufficient particle dose, thermograms will accumulate in the image pickup tube. Problems arise, such as leakage of charges that form an image and loss of contrast. Furthermore, the dynamic range of this type of image pickup tube is not inherently large.

Even if the dynamic range is relatively large, none exceeds 103.

The inventors of the present invention believe that images that cannot be captured with the above-mentioned device,
In order to obtain an image with a smaller amount of incident particle beam per unit time while maintaining a satisfactory contrast, we can measure the electrons in units of single electrons generated from the electron emitting surface that emits electrons when particles are incident. We focused on the fact that it is possible to measure δ1 of a weak two-dimensional image by specifying the generation position and counting the frequency of occurrence of electrons from each generation position by 61 numbers. There were two basic problems that had to be solved when attempting to realize the above idea using a microchannel play and a semiconductor device detection apparatus, which will be described later.

The first problem is that the signal due to a single particle is multiplied by the microchannel plate and localized by the semiconductor device detector;
It is necessary to distinguish between thermal SMC sounds and the like that are generated in semiconductor device detectors and the like.

The second problem is that even though the average value of the generation interval of single electrons generated from the entire surface of the electron emitting surface is sufficiently time-resolvable, it may become partially time-resolvable. be.

When inputs caused by two or more single electrons occur within a fixed time period that cannot be separated, a semiconductor device detection device outputs information on an average position that is not one of the respective incident positions. do. Therefore, if the generation interval of a single electron cannot be resolved in time by a semiconductor device detection device, the semiconductor device detection device will output noise that is unrelated to the image even though the input signal is caused by electrons. . The second problem will be related to the problem of signal-specific noise.

This signal-specific noise problem is less fundamental than the first device-specific noise problem, and is an acceptable problem in some cases where the probability of time-resolved failure is extremely low.

The inventors of the present invention solved the problem of noise inherent in the device as follows.

The multiplication factor of the microchannel plate is selected such that the microchannel plate amplifies single electrons sufficiently to distinguish them above the level of noise inherent in the device, and the variation in the multiplication factor is extremely small. I did it like that. The signal is then separated by a pulse height selector having a threshold between the signal caused by single electrons and the noise inherent in the device.

The problem of noise inherent in the signal is also solved as follows. When the output of the microchannel plate due to two or more electrons is incident on the semiconductor device detection device simultaneously or at an interval that cannot be resolved in time, the output of the semiconductor device detection device is larger than that in the case of a single electron. Become. Therefore, it can be separated by a pulse height selector having a threshold between the signal caused by a single electron and the noise inherent in the signal.

The main object of the present invention is that the input for each electron, that is, the input for a single electron, generated from an electron emission surface collided with a particle beam from an image source to be measured can be time-resolved within a two-dimensional resolution unit. It is an object of the present invention to provide an image measuring device that uses particle beams to measure two-dimensional images that are extremely weak while maintaining good contrast.

Another object of the present invention is to provide an image measuring device caused by a particle beam, which solves the problems of the noise inherent in the device and the noise inherent in the signal.

Still another object of the present invention is to detect data caused by the particle beam, which is equipped with an output device capable of outputting in real time the data of the results of the image measurement caused by the particle beam or the first measurement image of the measurement process. An object of the present invention is to provide an image measurement device.

In order to achieve the above object, the particle beam-induced image measurement device according to the present invention provides an image measurement device that generates particle beam-induced images in which the frequency of occurrence of electrons emitted due to particle beams is resolvable in time. A measuring device, comprising: the electron emitting surface; and a microchannel plate that multiplies electrons from the electron emitting surface to a substantially constant number of electrons for each single electron;
A two-dimensional semiconductor device detector provided opposite to the emission surface of the microchannel plate and output signals from a position signal output electrode of the two-dimensional semiconductor device detector are operated to transmit electrons to the two-dimensional semiconductor device detector. □Add the output signal from the position signal output electrode of the two-dimensional semiconductor device detector and the input position calculation circuit that outputs the position signal incident on the two-dimensional semiconductor device detector.
an incident amount calculating circuit that outputs the amount of electrons incident on the two-dimensional semiconductor device detector; and determining whether or not the output corresponds to a single electron level based on the output of the incident amount calculating circuit, and outputting a determined output. 2. Adding a unit signal to a counter at an address designated by the output signal of the incident position calculation circuit when it is determined by the generated pulse height selector and the nog pulse height selector that it corresponds to a single electron level. It consists of a dimensional counter.

According to the configuration, an image of an ultra-weak particle beam can be detected in a high dynamic range.

The present invention will be described in more detail below with reference to the drawings and the like.

FIG. 1 is a block diagram illustrating an embodiment of an image measuring device caused by a particle beam according to the present invention.

This embodiment is applied to a transmission type electron microscope, and the particle beam in this embodiment is an electron emitted from an electron gun 101 and guided to a sample l by a focusing lens 102.

This corresponds to the surface of sample 1 that emits electrons. In this invention, the expression "a surface that emits electrons" is used in a broad sense to include an object when the distribution of uniformly incident electrons is changed when passing through the object, as in this example.

An image of the electrons transmitted through the sample 1 is formed on the incident surface of the microchannel plate 330 by the electron lenses 103 and 104 of the electron microscope and mirror. Both the microchannel plate 33 and the semiconductor device detector 34 are incorporated within the vacuum system of the electronic HRth mirror.

The image formed on the incident surface of the microchannel plate 33 is multiplied by the microchannels of the microchannel plate 33.

FIG. 2 shows the microchannel plate 33 and semiconductor device detector 34 taken out.

A power supply E3 is connected between the incident surface and the exit surface of the microphone r-1 channel plate 33.
An electric FAE 4 is connected between the emission surface of the semiconductor device detector 34 and the semiconductor device detector 34 .

The microchannel plate 33 has a large number of through holes (having a channel length) that connect from the incident surface to the exit surface, and a secondary electron emitting surface is formed on the inner wall of the through hole. The emission surface is lead oxide (PbO).The electrons incident on the incidence surface of the microchannel plate 33 are multiplied and emitted from the emission surface of the microchannel plate 33 while retaining the information of the incident position. In order to make the multiplication factor for multiplying one incident electron as close to a constant value as possible, the channels of Micro Channel Play-1 and 33 are set at 10 (l) with respect to the flow surface U and the channel mouth i. ft) or more.

This also increases the resistance of the dynode wall formed on the inner surface of the channel.

With this configuration, the multiplication factor of single electrons becomes a substantially constant value, and the microchannel plate 3 caused by all single electrons
3 and noise generated from the inner surface of the channel due to heat.

The semiconductor device detector 34 is a two-dimensional position detector that outputs a current signal corresponding to the incident position when electrons are incident on its incident surface.

The structure and operation of the semiconductor device detector 34 will be described in detail in conjunction with the explanation of the structure and operation of the incident position calculation circuit r/84 (FIG. 1).

The incident position calculation circuit 4 generates a position signal (hereinafter represented by This is an arithmetic circuit that calculates and outputs (represented by Z).

The pulse height selector 5 has a first threshold value set between the center of the Z output signal caused by a single electron of the incident position calculation circuit 4 and the output due to thermal noise from a microchannel plate, etc. It is a window comparator with a second threshold set between the signal and the output due to inherent noise.

However, in some cases, the second threshold value may be omitted and “ζ
It is also possible to extract all signals greater than the first threshold.

The first address signal generator 6 outputs a signal specifying each counter address of the two-dimensionally arranged counters 11 from the X and Y signals of the device arithmetic circuit 4 composed of an analog-to-digital converter.

n several types of 7, the output pulse of the clock pulse generator 10 is 4
is reset by the vertical and horizontal synchronization signals of the synchronization signal generator 17. The 61 value reset by the vertical synchronization signal represents the Y coordinate, and the 51 value reset by the horizontal synchronization signal represents the X coordinate.

The 27th address signal generator 8 converts the output signal of the 11 digit counter 7 into a signal specifying the address of the two-dimensional counter 11.
Convert. The first selection gate circuit 20 selects either the output signal (write address signal) of the first address signal generator 6 or the external address signal (read address signal). 1- Leads to circuit 9.

The first selection gate-circuit 9 is the first selection gate-circuit 20.
Either the output signal of the address signal generator 8 or the output signal of the second address signal generator 8 is selected by the output signal of the ⅛ counter IB and passed to the two-dimensional counter 11.

The two-dimensional memory 111 of the two-dimensional counter 11 is formed by associating a large number of counters with two-dimensional pixels.

The detailed configuration of the two-dimensional counter 11 will be explained with reference to FIG. The two-dimensional counter 11 includes a two-dimensional memory 111.
and a buffer memory 112 connected to the data output terminal of the two-dimensional memory 1■I, and a third selection gate circuit that selectively sends the output of this buffer memory 112 to the incrementer 115 or to the outside according to an external command. 1
14. Incrementer 1 that adds 1 to the input signal and sends it out
15, this incrementer 115 and the two-dimensional memory 11
an input buffer memory 11 connected to the data input end of 1;
6. Putting the two-dimensional memory 111 into a state where either reading or writing is possible 1', Rai I, Control circuit 1
Contains 21.

This two-dimensional counter 11 receives the output signal of the pulse height selector 5 from the first input terminal 1 of the read/write control circuit 121.
22, the contents of the counter at the address specified by the output signal of the first address signal generator are set to 1.
(unit signal) is added.

This operation will be called counting. Further, the contents of the counter at the address specified by the second address signal generator 8 are read out and used for reading by a television monitor, which will be described later. The contents of the two-dimensional counter II are not reset to the 61 numerical value by reading out.

The detailed operation of arguments and reading will be described later.

12 and 12' are buffer memories, and 13 is a scale controller. The number of digits to be shifted by the output signal of the buffer memory 12 (this is a parallel signal consisting of a plurality of bits) depends on the output of the highest order detector 14. Highest detector 1
4 detects the highest level of "1" among the output signals in the binary signal format of the buffer memory 12. Then, if the highest level of "1" among the output signals of the buffer memory 12 is not higher than the already detected level, the highest level detector 1
The output of 4 is retained. The position controller 13 shifts the digits so that the place indicated by the output signal of the highest position detector 14 becomes the most significant output of the position controller 13, and outputs the °ζ data. 15 is a digital to analog converter. I9 is a synchronous mixer which synthesizes the output of the digital-to-analog converter 15 into a standard television video signal. 16 is a television monitor. Displays the video signal on a cathode ray tube.

This operation will be referred to as television reading.

The reason why the LJ is displayed at a certain level from the highest level on the TV monitor is to eliminate the difficulty in viewing the image due to the small number of TV monitors.

FIG. 3 shows a block diagram of the semiconductor device detector 34 and the position calculation circuit 4 for calculating the output signal of the semiconductor device detector 34. The semiconductor device detector 34 has a p-n junction plane parallel to the surface of the silicon semiconductor, and four electrodes 35, 36, 37, 3 electrically separated into parts corresponding to the four sides of a rectangle.
8 is formed. Here, it is assumed that electrodes 35 and 36 are facing each other, and electrodes 37 and 38 are facing each other. The electrical resistance between any point 39 on the surface surrounded by the four electrodes 35.3G and 37.38 and each of the electrodes is proportional to the distance therebetween. Therefore, when electrons are incident on the point 39, a current that is inversely proportional to the distance from each electrode to the point 39 is sent out. At this time, electron multiplication occurs within the silicon semiconductor in response to the energy of the incident electrons. 41, 42, 43.4
4 is a pulse amplifier. 45, 46, 47.48 are integrators. A timing signal generator 56 adds the outputs of the pulse amplifiers 43 and 44, uses this as a trigger signal, and generates a timing signal. This timing signal limits the timing for starting the integration of the integrators 45, 46, 47, and 48 and the product time. This integration time is, for example, 6 microseconds. This time is determined in accordance with the magnitude of the time constant of the output signal of the semiconductor device detector 34. Further, this time is sufficiently longer than the cycle of operation of a two-dimensional counter, which will be described later.

Note that when there is a delay time in timing generation in the circuit shown in FIG. 3, the integration start time will be delayed with respect to the input signal, and there is a possibility that the integration accuracy will deteriorate. In such a case, it is necessary to insert a delay circuit between the pulse amplifiers 41, 42, 43, 44 and the corresponding integrators 45, 46, 47, 48, respectively.

In FIG. 3, the current sent from the electrode 35 is amplified by a pulse amplifier 41, and the signal current obtained by integrating it by an integrator 45 is 135. The current sent out from the electrode 36 is amplified by the pulse amplifier 42, and the signal current obtained by integrating it by the integrator 46 is processed as follows: 36. The current sent out from the electrode 37 is amplified by a pulse amplifier 43, and the signal current obtained by integrating it by an integrator 47 is amplified by a current pulse amplifier 44 sent out from I37 and the electrode 38, and the signal current is integrated by an integrator 48. Assume that the signal current that has been removed is 138.

The W adder 50 receives the outputs 135 and 13 of the integrators 45 and 46.
(Adds i and outputs (135+136).

The adder 52 receives the outputs I37 and 13 of the integrators 47 and 48.
Add '8 and output (137+138).

The adder 55 adds the outputs of the adders 50 and 52 to obtain (
+ 35 + 136 + 137 + 138).

Similarly, subtractor 49 (35-136), subtractor 5
1 outputs (137-138).

53 and 54 are dividers, and the output signal X of the divider 53
is given by the following equation.

X = (135-136) / (135+ 136
> (1) The output signal Y of the divider 54 is given by the following equation.

Y= (137-138) / (137+ 138)
(2) The output signal Z of the adder 55 is given by the following equation as described above.

Z-(135+ 136+ 137+ 138) ・
(3) The center of the square surrounded by the four electrodes 35, 36, 37, and 38 is the origin, the distance of each electrode from the origin is 1, and the direction from the electrodes 36 to 35 is the X direction electrode 38.
By defining the direction from to 37 as the Y direction, (1
), (2), and (3) have the following meanings, respectively.

(1) 2 X coordinate (X) of electron incident point 39 (2) 2
Y coordinate of the electron incident point 39 (Y) (3) Equation (3) Incident amount of electrons (Z) Next, the operation of the embodiment device will be explained together with the detailed configuration.

At the start of operation, the first selection gate circuit 20
The address signal generator 6 and the second selection gate circuit 9 are connected, and the third selection gate circuit 114 is connected to the output sofa 112.
and incrementer 1150.

The image of electrons transmitted through sample 1, which is the electron emission surface, is an electron microscope!
l [formed on the incident surface of the microchannel plate 33 by the mirror electron lenses 103, 104, and 105.

The incident electrons are multiplied by the microchannel plate 33 and reach the exit surface. The multiplied electrons emitted from the emission surface enter the semiconductor device detector 34. The position of the light incident point on the photocathode 31 is also maintained between the two.

Here, the relationship between the Z signal and the threshold value of the pulse height selector 5 will be explained with reference to FIG.

FIG. 4 is a histogram showing the Z signal pulse height on the horizontal axis and the frequency of each output value on the vertical axis.

A Z signal pulse appears every time a single electron is generated on the electron emission surface, and only an output with the same pulse height should appear for every single electron, but in reality, two pulses are generated as shown in Figure 4. It appears as a distribution with peaks p+q. This curve can be estimated to be given as the sum of the output frequency distribution B caused by thermal noise, the output distribution A caused by single-unit electrons, and the output distribution C when electrons are generated continuously to the extent that they cannot be separated. .

Therefore, in the present invention, the threshold of the pulse height selector 5 is set at two points L and II in the figure, and only the Z output between them is measured.

The X position signal and Y position signal from the incident position calculation circuit 4 are as follows.
The two-dimensional counter 11 is controlled by the first address signal generator 6.
is converted into an address signal of select gate times FIj & 9
2-dimensional counter 1. Specify the address of L.

Since the maximum repetition period of the output of the incident position calculating circuit 4 is longer than the operation cycle of the two-dimensional counter 11, the two-dimensional counter 11 may be inputted when the output of the incident position calculating circuit 4 is generated.

The two-dimensional counter 11 has 512×512=262144 counters, in other words, the two-dimensional memory 111 has 2621 counters.
Assume that it has 144 memory locations. The Z signal from the incident position calculation circuit 4 is input to a wave height selector 5. The wave height selector 5 sends out a trigger signal pulse when the Z signal is between the arbitrarily set lower limit and the 11-unit limit, and the two-dimensional counter 11 detects the specified address when receiving the pulse. Add 1 to the contents of the counter. In this way, only the signal corresponding to one electron can be applied to the two-dimensional counter 11, excluding thermal noise and pulses corresponding to two electrons.

The frequency of the clock pulses is selected so that one clock pulse corresponds to each pulse of the two-dimensional counter 11, and also taking into account the retrace period of television scanning. As described above, the address in the X direction can be specified by the value obtained by multiplying the frequency of the clock pulse by 81 after the d1 counter 7 resets the frequency using the horizontal synchronizing signal.

The address in the Y direction does not require 81 clock pulses or 1ζ, but after resetting with the vertical synchronization signal, it is sufficient to multiply the number of horizontal synchronization signals by the number of stitches.The output of the incident position calculation circuit 4 is located at the center of the screen. On the other hand, the argument value output from the Tsuba 1 counter 7 has the upper left corner of the screen as the origin, and the reading order is compatible with the interlaced scanning method. Appropriate correction must be made.The second address signal generator 8 corrects the argument value output from the δ] digit 7 and converts it into an address signal for the two-dimensional counter 11.

For example, the correction is 512/2=512/2 for the count value in the X direction.
256, and in the Y direction ζ is twice the number of hazes in one horizontal scan, and in the first foot is 245.
and in the second foort, 244 is subtracted.

The second selection gate circuit 9 is controlled by pulses obtained by frequency-dividing the output of the clock pulse generator IO by a 1/8 counter 18. FIG. 5 shows the waveform sent out from the 1/8 counter 18. This controls the basic timing (basic cycle) of the two-dimensional memory 111, and is divided into a first half and a second half, as shown in FIG. The first half of one cycle is “l”
” (high state) and the latter half is “0” (low state). This pulse causes the second selection gate circuit 9
is used to read the δ1 number or contents to the outside through the address signal or external address signal output from the first address signal generator in the first half of the cycle, and is used to read the δ1 number or contents to the outside through the address signal output from the first address signal generator or the external address signal, and in the second half the output from the second address signal generator is used. The content of the two-dimensional counter is used to read out the contents of the two-dimensional counter using the television system through the address signal.

The pulse outputted from the 1/8 counter 18 to the second selection circuit 9 is also outputted to the two-dimensional counter 11, and the pulse height selector 5
However, only when one trigger signal pulse is sent to the first input terminal 122 of the read/write controller 121, the two-dimensional memory 111 designated in the first half of the basic cycle shown in FIG.
The incrementer 115 reads out the address memory contents of
1 is added and written to the same address in the two-dimensional memory 111 in the first half of the next basic cycle shown in FIG. 5, 1-2.

This operation performs the above-mentioned counting. Figure 5 1
2.1 In the latter half of each basic cycle, the memory contents of consecutive 8 (lift) addresses are read non-destructively from the specified address. Used for reading.

The reason for reading out the signals of eight counters at once is as follows. If you read out the counter signal of 1 in cycle 1, then 9
．． The read cycle is 7M1lz.

Furthermore, since the data must be read out in the latter half of one cycle, the time given for one readout is 52 nanoseconds. This is when 111 currently available equipment is either impossible or close to its limits. 8111
If the counter of i1 is read out at once, the time given for one readout is 416 nanoseconds, which is sufficient.

This reading operation follows the horizontal and vertical synchronization signals sent by the television synchronization signal generator 17. Such an operation is called parallel-to-serial conversion. Also, as mentioned above, the two-dimensional counter 11 has 512 x 512 counters, so 5120 counters correspond to one horizontal scanning line.If 8 are read at once, one horizontal scanning line is processed by 64 readings. can. There are 525 scanning lines in the external television, but 6.5% of them correspond to the vertical blanking period, so only 488 lines are displayed.

The output signals of the eight counters read from the two-dimensional counter 11 are temporarily stored in the first buffer memory 12B,
The output signals of each counter are read out sequentially. The next one cycle, ie, 816 nanoseconds, is allocated for reading from the first buffer memory 12B. In the latter half of the cycle in which reading is being performed from the first buffer memory 12B, the data is transferred from the two-dimensional counter 11 to the second buffer memory 12B.
Reading is performed at 9. Therefore, it is obvious that a selection gate that is switched every cycle is required between the output terminal of the two-dimensional cow counter and the input terminals of the first and second platform memories 128 and 129. The explanation will be omitted. The signal output from the first pamphlet memory 12B or the second pamphlet memory 129 is input to the scale controller 13 and also to the highest rank detector 14. The highest order detector 14 detects which digit of the output signal of the buffer is the highest order which is "1".

The highest level detector 14 detects the highest level of all inputs, but unless a signal larger than the previous input is input,
The output signal is retained.

A position controller 13 shifts the input signal in response to the output of the highest position detector 14. That is, the digit of the input signal indicating the output of the highest detector 14 is shifted so that it becomes the same digit as the lightning in the output signal.

The output of the scale controller 13 is sent to the digital-to-analog converter 15.
The horizontal and vertical synchronization signals sent from the television synchronization signal generator 17 are mixed by a synchronization mixer after being converted into analog signals by the television monitor 16.
Input video number 18 as ゛ζ.

Here, when the observer recognizes that the image displayed on the television monitor 16 is good, he activates the first selection gate circuit 20 by an external address selection signal by manual operation. The first selection gate circuit 20 is
Open the gate between the external address generator (not shown) and the second selection gate circuit 9. 2D counter 1 at the same time
1, the external address selection signal is sent to the third selection gate circuit 11.
4 and the second input terminal 123 of the write control circuit 121. At this time, the read mode P' is entered in the first half of the basic cycle shown by 'r, +'r2 in FIG. 5. At this time, A gate between the output buffer 112 and an external display device (not shown) opens, and a gate between the output buffer 112 and increment 1 and 15 closes.The memory 111 is also in read mode during the first half of the basic cycle. Become.

At the same time, an arbitrary address signal is sent to the first selection gate circuit 20 from the external address generator.

Through this simple operation, the 2D counter 11 is transferred from the 2D counter 11 through the third selection gate circuit 114.
The image signal stored in the two-dimensional memory 111 can be output as a digital signal to an external display device and an external storage device.

At this time, the contents of the two-dimensional memory 111 are read out
Nothing will change.

An example of an external display device is a printer and an example of an external storage device is Magnedec tape.

The addresses for this readout may be in the same order as the readout for television display described above. Alternatively, only a specific part of the image may be used.

For example, two periods of a clock pulse of 9.7M1lz are used as the readout speed. Only one counter is read for each read. These can be fully understood from the configuration and operation of this embodiment described above.

Since the present invention is configured and operates as described above, it has the following effects.

By using a microchannel plate that multiplies a single electron to a number of electrons close to a certain value, and by setting a lower limit on the wave height of the detection pulse with a two-dimensional semiconductor device detector, the position where the electron is generated is detected. A two-dimensional image can be measured by removing noise components due to thermal noise.

Furthermore, since this is digitally counted using a two-dimensional counter, it can be observed over a wide dynamic range. In this embodiment, by setting each address of the two-dimensional counter to 16 bits, a dynamic range of 6 x 104 is obtained. It no longer indicates the location. It removes the output (signal-specific noise) caused by two electrons incident at the same time, enabling more accurate image detection.

By displaying the output of the two-dimensional counter on a television, the image being formed can be observed in real time, and the optimal timing for reading image information can be determined.

Although the particle beam in the above embodiment is an electron, the microchannel plate 33 shown in the above embodiment emits secondary electrons even if the particle beam is a particle beam or a neutron. , or may be an image using a particle beam such as these. Further, a microchannel plate 33 and a semiconductor device detector 34 are provided in a vacuum-tight container 3 as shown in FIG. 7, and a surface 31 is provided on the inner wall of the vacuum-tight container 3 to hkIJl ``ζ electrons by particles. It may be.

32 is a focusing electrode, El, E2. E3. E4 is a bias power supply.

The present invention can also be used to measure mass spectrum images using ions in a mass spectrometer, as well as to measure images using elementary particles with appropriate energy.

Lead oxide can be used as an electron-emitting surface because it emits electrons when most types of particles are incident on it.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the image measurement device for particle beam-induced image measurement according to the present invention, Fig. 2 is a schematic diagram showing a microchannel plate and a semiconductor device detector taken out, and Fig. 3 is a semiconductor device detection Figure 4 is a histogram showing the distribution of the Z output of the incident position calculation circuit, and Figure 5 shows the pulses sent from the clock pulse generator to the 1/8 counter. The waveform diagram in Fig. 6 shows the detailed structure of the two-dimensional counter.
Vacuum-tight container 31...electron emission surface 32...focusing electrode 33...
Micro channel play-1, 34... Semiconductor device detector 4... Incident position calculation circuit 4 42, 43.44... Pulse multiplier 45.46
, 47.48... Integrator 49.51... Subtractor 50.52. ．． 55... Adder 53, 54... Divider 5... Pulse height selector 56... Timing signal generator 6... First address signal generator 7... Counter 8... Second address signal generator 9...First selection gate/circuit 10...Clock pulse generator 11...Two-dimensional counter 111...Two-dimensional memory 112, 116, 128, 129... Sofa Memory 114...Selection gate circuit 115...Incrementer 13...Scale control device 14...Highest level detector 15...Digital analog converter 16...Television monitor 17...Synchronization Signal generator 18...1/8 counter 19...Synchronous mixer 20...First selection gate circuit 21...Gate circuit Patent applicant: Hamamatsu Television Co., Ltd. Agent Patent attorney: Inoro Juji' 21・1 3] □8 51'4+q mer51te

Claims (1)

[Scope of claims]
The measuring device includes the electron emitting surface, a microchannel plate that multiplies electrons from the electron emitting surface to a substantially constant number of electrons for each single electron, and a microchannel plate facing the emission surface of the microchannel plate. an incident position calculation for calculating output signals from a two-dimensional semiconductor device detector provided and a position signal output electrode of the two-dimensional semiconductor device detector and outputting a position signal at which electrons are incident on the two-dimensional semiconductor device detector; an incident amount calculation circuit that adds output signals from position signal output electrodes of the two-dimensional semiconductor device detector and outputs the amount of electrons incident on the two-dimensional semiconductor device detector; and the incident amount calculation circuit. a pulse height selector that determines whether the output corresponds to a single electron level based on the output of the pulse height selector and generates a determined output; An image measuring device caused by a particle beam, which includes a two-dimensional counter that adds a unit signal to a counter at an address specified by an output signal of an incident position calculation circuit. (2) The wave height selector has a first threshold for separating low-level thermal noise output from output caused by single electrons, and images caused by particle beams according to claim 1. Measuring device. (3) The pulse height selector further comprises a second threshold for separating signal-specific noise caused by simultaneous generation of two or more electrons from output caused by a single electron. An image measuring device caused by the particle beam described in item 2. (4) An image caused by a particle beam according to claim 1, wherein the particles are electrons emitted from an electron gun of an electron microscope, and the electron emission surface is a sample placed within the electron microscope. Wave measurement device (5) An image measurement device caused by a particle beam in which the frequency of occurrence of electrons emitted due to the particle beam is time-resolvable, which includes the electron emission surface and the front electron emission surface. a microchannel plate that multiplies electrons from the . an incident position calculation circuit that calculates an output signal from a position signal output electrode of the detector and outputs a position signal that electrons are incident on the two-dimensional semiconductor device detector; and a position signal output electrode of the two-dimensional semiconductor device detector. an incident amount calculation circuit that adds the output signals of and outputs the amount of electrons incident on the two-dimensional semiconductor device detector; and whether or not the output of the input amount calculation circuit corresponds to a single electron level. a pulse height selector that discriminates and generates a discrimination output; and when the pulse height selector determines that the pulse height selector corresponds to a single electron level, the address specified by -ζ is determined by the r output signal of the incident position calculation circuit. An image measuring device caused by a particle beam, comprising a two-dimensional counter that adds a unit signal to a counter, and an output device that outputs the contents of the two-dimensional counter. (6) The wave height selector has a first threshold value for separating the low-level thermal noise output by Plt1° from the output caused by a single electron. Image measurement device. (7) The pulse height selector eliminates the signal-specific noise caused by the simultaneous generation of two or more electrons by 1'l! from the output caused by a single electron! 7. The image measuring device caused by a particle beam according to claim 6, further comprising a second threshold for measuring the value. (8) The image measuring device caused by a particle beam according to claim 5, wherein the output device is a television monitor device, and is configured to display the contents of the two-dimensional counter during ζδ1 measurement in real time. . (9) The image measuring device caused by particle beams according to claim 8, wherein the output device further includes a printer device that outputs the contents of the two-dimensional counter as numerical data. α0) The image measuring device caused by a particle beam according to claim 8, wherein the output device is a Magnedec tape device that externally stores the contents of the two-dimensional counter.