JPH0254852A - Composite charged particle beam device - Google Patents

Abstract

PURPOSE:To facilitate the judgment of a charged particle photograph by digitally displaying the device switching the polarity of the accelerating voltage generated by an accelerating voltage generator in response to the switching of an ion generating source and an electron generating source and the accelerating voltage value switched with the polarity on a display device. CONSTITUTION:The voltage corresponding to the acceleration voltage V'a from an adder 31 and the voltage corresponding to the sample applied voltage V's set by a sample applied voltage setting circuit 26 are converted into digital signals by AD converters 33, 32 and 34 respectively and fed to a character signal generating circuit 35. The voltages corresponding to the exciting voltage V'o, accelerating voltage V'a, and sample applied voltage V's and their polarities are displayed in numerals together with the charged particle image of a sample on the display screen of the display device. When the picture of the screen is photographed, the voltages corresponding to the exciting voltage V'o, and acceleration voltage V'a and sample applied voltage V's and their polarities are displayed in numerals at the end section of this picture together with the charged particle image of the sample.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a composite charged particle beam device that has the functions of both an ion beam device and an electron beam device in one column, and in particular, This invention relates to a composite charged particle beam device in which it is possible to easily determine whether an image based on charged particles from a sample obtained in an electron beam device mode or an ion beam device mode is obtained.

[Prior Art] Recently, a composite charged particle beam device has been developed in which a single lens barrel has the functions of an electron beam device such as an electron microscope and an ion beam device such as a focused ion beam device. In such a device, the ion source and the electron R
(electron guns) are placed adjacent to each other, and when in ion beam device mode, only the ion source is activated, and when in electron beam device mode, the electron source is activated, or when in ion beam device mode, the lens barrel length is An ion source is attached to the center of the apex and operated, and when in electron beam device mode, an electron source is attached to the same part and operated. In each mode, an ion beam or an electron beam from an ion source or an electron source is focused onto a target by a common objective lens, and the beam is shot at a predetermined position on the target by a common deflection system. Then, if necessary, charged particles generated from the target are detected by a charged particle detector, and an image based on the charged particles is displayed on a display device or photographed.

[Problems to be Solved by the Invention] As described above, the mode is occasionally switched in the composite charged particle beam device, and the charged particle image photograph p (, later, Sometimes I can't tell which mode the photo is in.

Furthermore, even when viewing a charged particle image on a display device, it is often difficult to immediately know which mode it is in.

The present invention aims to solve such problems and provides a novel composite charged particle beam device.

[Means for Solving the Problems] To this end, the composite charged particle beam device of the present invention is configured to be able to switch between an ion source and an electron source, and the switched source. an accelerating voltage generating means for applying a voltage to accelerate the charged particle beam from the source in the direction of the target; a lens system for focusing the charged particle beam and irradiating it onto the target; and scanning the target with the charged particle beam. A composite charged particle beam device comprising: a means for detecting charged particles generated from the target by scanning; and a means for displaying a target image based on the charged particle beam from the target, the ion source and the electron source; means for switching the polarity of the accelerating voltage generated from the accelerating voltage generating means in response to switching of the accelerating voltage, and a mechanism for digitally displaying the accelerating voltage value with the switched polarity together with the polarity on a part of the display section of the display device. Prepared.

[Embodiment] FIG. 1 is a schematic diagram of a composite charged particle beam generator shown as an embodiment of the present invention.

Incidentally, in this embodiment, a beam irradiation method is used that can maintain the device resolution at a high level without damaging the target. That is, if the accelerating voltage is increased, the beam can be narrowed down, so if the target is irradiated with the beam, the resolution can be increased, but the damage to the target is large.

Of course, lowering the accelerating voltage will reduce damage to the target, but since the beam cannot be narrowed down, the resolution will decrease. Therefore, the accelerating voltage is set high, and the target is applied with a voltage (
The beam is accelerated at a high accelerating voltage by applying a target applied voltage), but the target is irradiated with energy based on the voltage corresponding to the difference between the accelerating voltage and the target applied voltage. This made it possible to maintain high resolution without damaging the target. This method is called the retarding method.

In the figure, 1 is an ion source, 2 is an electron source (electron gun), 3.4 is a focusing lens, 5 is a deflector, 6 is an aperture plate, 7X
, 7Y are X-direction and Y-direction deflectors, 8 is an objective lens,
9 is a sample (target), 10 is a charged particle detector, 11
12 is an amplifier, 12 is a display device such as a cathode ray tube, 13 is a scanning signal generating circuit, 14 is an accelerating voltage generating circuit, 15 is a sample applied voltage generating circuit, and 16 is a DC power supply. The accelerating voltage generating circuit 14. In the sample applied voltage generation circuit 15, 17
．． 18 is an oscillation drive circuit, 19.20 is a step-up transformer, 21.22 is a rectification and ripple removal circuit, 23.24
25 and 26 are respectively an acceleration voltage setter and a sample voltage setter, 27 and 28 are error amplifiers, 29 and 30 are polarity switching circuits, and 31 is an adder circuit. Also, 32.33
．． 34 is an AD converter, 35 is a character signal generation circuit, 36 is a polarity switching command circuit, and 37 is a source switching circuit.

In such a device, for example, when setting the device to ion beam mode so that it operates as an ion beam device, the polarity switching command circuit 36, source switching circuit 37,
A polarity switching command is sent to each polarity switching circuit 29, 30, rectification and ripple removal circuit 21, 22, and character signal generation circuit 35. Then, the source switching circuit 37 applies an accelerating voltage only to the ion source 1, and the rectification and ripple removal circuit 21
゜22 is a polarity switching circuit 29.30 that switches a built-in diode (not shown) to generate a positive polarity voltage.
The polarity is switched so that the signals detected by the voltage detection resistors 23 and 24 have positive polarity, and the polarities of the voltages of the acceleration voltage generation circuit 14 and sample applied voltage generation circuit 15 are both positive.

Hereinafter, the voltage (hereinafter referred to as
energizing voltage), for example V.

The case of energizing with (KV) energy will be described.

First, the energizing voltage Vo is set in the acceleration voltage setting device 25. Then, taking into consideration the magnitude of the accelerating voltage, the sample applied voltage Vs is set in the sample voltage setting device 26. Then, adder 3
1 inputs into the error amplifier 27 a current corresponding to the sum of the energizing voltage Vo and the sample applied voltage Vs (Vo+Vs). The error amplifier 27 controls the oscillation drive 17 that oscillates the DC voltage from the DC power supply 16 at several tens of KH2, and from the oscillation drive 1/1 of the accelerating voltage to be set.
Generate a voltage of N. This voltage is boosted N times by the step-up transformer 19 and sent to the rectification and ripple removal circuit 21, so that a predetermined accelerating voltage is generated from this circuit. At this time, a voltage corresponding to the accelerating voltage from the rectification and ripple removal circuit 21 is detected by the voltage detection resistor 23, and a current corresponding to the voltage enters the error amplifier 27 through the polarity switching circuit 29, so that the error amplifier feeds back the difference between the current corresponding to the detected accelerating voltage and the output of the adding circuit 31 (current corresponding to the accelerating voltage) to the oscillation drive 17, and outputs a predetermined acceleration of positive polarity from the rectifying and ripple removing circuit 21. Make sure that voltage is generated.

The sample applied voltage is also set by the sample applied voltage setting device 26,
A current corresponding to the set voltage enters the error amplifier 28. The error amplifier converts the DC voltage from the DC power supply 16 to several tens of KH.
2, the oscillation drive 18 which is being oscillated is controlled, and the oscillation drive generates a voltage that is 1/N of the sample applied voltage to be set.

This voltage is boosted by N times by the step-up transformer 20 and sent to the rectification and ripple removal circuit 22, so that a predetermined sample applied voltage of positive polarity is generated from the circuit.

At this time, a voltage corresponding to the sample applied voltage from the rectification and ripple removal circuit 22 is detected by the voltage detection resistor 24, and a current corresponding to the voltage enters the error amplifier 28 through the polarity switching circuit 30, so that the error The amplifier feeds back the difference between the detected current corresponding to the sample applied voltage and the current corresponding to the sample applied voltage set by the sample applied voltage setting device 26 to the oscillation drive 18, and outputs a predetermined value from the rectification and ripple removal circuit 22. so that a voltage applied to the sample is generated. As a result, the accelerating voltage generating circuit 14 generates a positive accelerating voltage Va and applies it to the ion source 1. At this time, at the same time, the sample applied voltage generation circuit 15 generates a positive sample applied voltage Vs and applies it to the sample 9. Then,
Ions generated from the ion source 1 are accelerated by an accelerating voltage Va and head toward the sample. At this time, the deflector 5 is in an off state, that is, in a non-deflecting state, so that the ion beam can pass through the hole in the aperture plate 6. The ion beam is focused onto the sample by the focusing lens 3 and the objective lens 8, and at the same time is scanned over the sample by the X-direction and Y-direction deflectors 7X and 7Y. At this time, the acceleration voltage V
Ions energized with energy corresponding to the difference (Va-Vs) between a and the sample applied voltage Vs are irradiated. Charged particles such as secondary electrons and secondary ions generated from the sample by the scanning are detected by the charged particle detector 10 and are detected by the amplifier 11.
is sent to the cathode ray tube 12 via. Since X and Y scanning signals are sent to the cathode ray tube 12 from the scanning signal generation circuit 13 in synchronization with the supply to the X and Y direction deflectors 7X and 7Y, the images on the screen of the cathode ray tube are The sample image is displayed.

Now, the energizing voltage V set by the acceleration voltage setter 25
o, the acceleration voltage V from the adder circuit 31
The voltage corresponding to a and the voltage corresponding to the sample applied voltage Vs set by the sample applied voltage setting circuit 26 are converted into digital signals by AD converters 33, 32, and 34, respectively, and sent to the character signal generation circuit 35. . The character signal generation circuit 35
, X and Y scanning signals are sent from the scanning signal generation circuit 13 to the X and Y direction deflectors 7X and 7Y in synchronization with the supply, and the character signal generation circuit is connected to the display device. A display point designation signal is created so that each voltage value is displayed on a part of the display screen (for example, the edge portion of the display section), and the display point designation signal and each of the above-mentioned energizing voltages 0, acceleration voltage Va,
A digital value of the voltage corresponding to the sample applied voltage VS is sent to the display device. Therefore, the display screen of the display device displays the charged particle image of the sample as well as the energizing voltage VO and accelerating voltage Va.

The voltage I corresponding to the sample applied voltage Vs is displayed in numbers along with its polarity (+ in this case, according to the polarity command from the polarity switching command circuit 36). Therefore, when a photograph is taken from the screen, the charged particle image of the sample is included in the photograph, as well as the energizing voltage Vo and the accelerating voltage Va at the ends.

The voltage corresponding to the sample applied voltage Vs is shown numerically along with its polarity (+ in this case).

Note that when changing the acceleration voltage, the sample voltage setting device 26
to change the setting value of the sample applied voltage on the setting device. That is, the sample applied voltage is the difference between the accelerating voltage and the energizing voltage, and since the energizing voltage is initially fixed, for example,
To increase the acceleration voltage by AKV, use the sample voltage setting device 2.
The sample applied voltage set in step 6 is also increased by AKV. Also, for example, to lower the acceleration voltage BKV, the sample voltage setting device 2
The sample applied voltage set in step 6 is also lowered by BKV.

In addition, when changing the magnitude of the energizing voltage, first set the energizing voltage in the accelerating voltage setting device 25, and while the set voltage is fixed, determine the magnitude of the accelerating voltage. An appropriate sample applied voltage is set in the sample voltage setting device 26 depending on whether the sample voltage is to be applied or not.

Next, in such a device, when setting the device to electron beam mode so that the device operates as an electron beam device,
From the polarity switching command circuit 36 to the source switching circuit 37, each polarity switching circuit 29, 30, the rectification and ripple removal circuit 21.
A polarity switching command is sent to 22 and character signal generation circuit 35. Then, the source switching circuit 37 switches so that the accelerating voltage is applied only to the electron source 2. The rectification and ripple removal circuits 21 and 22 switch the diodes so that negative polarity voltage is generated, and the polarity switching circuits 29 and 30 switch the signals detected by the voltage detection resistors 23 and 24 to positive polarity to generate the accelerating voltage generation circuit 14. The polarities of the voltages of the sample applied voltage generating circuit 15 and the sample applied voltage generating circuit 15 are both changed to negative polarities.

Hereinafter, a case will be described in which electrons irradiating a sample are energized with a voltage (hereinafter referred to as an energizing voltage) that provides energy to the electrons to an extent that does not damage the sample, for example, an energy of Vo''.

First, the energizing voltage V is applied to the acceleration voltage setting device 25.

Set. Then, considering the magnitude of the accelerating voltage, the sample applied voltage Vs- is set in the sample voltage setting device 26. Then, the adder 31 receives the energizing voltage V.

' and the sample applied voltage Vs- (V.

+Vs-) is applied to the error amplifier 27.

Thereafter, the operation is the same as in the ion beam device mode, and a predetermined acceleration voltage of negative polarity is generated from the acceleration voltage generation circuit 14.

Similarly to the sample application voltage in the ion beam device mode, a predetermined sample application voltage of negative polarity is generated from the sample application voltage generation circuit 15. As a result, the accelerating voltage generating circuit 14
A negative acceleration voltage Va is generated and applied to the electron source 2. At this time, at the same time, the sample applied voltage generation circuit 15 generates a sample applied voltage Vs= of negative polarity and applies it to the sample 9. Then, the electrons generated from the electron source 2 are accelerated by the accelerating voltage Va- and move toward the sample. At this time, the deflector 5 is in an on state, that is, in a state of deflection such that the electron beam can pass through the hole in the aperture plate 6.

The electron beam is focused onto the sample by a focusing lens 4 and an objective lens 8, and at the same time is deflected by an X-direction and a Y-direction deflector 7X.
, 7Y to scan the sample. At this time, the sample 9 has a difference (Va -
-Vs-) is irradiated with ions energized with energy corresponding to -Vs-. Charged particles such as secondary electrons and backscattered electrons generated from the sample by the scanning are detected by a charged particle detector 10 and sent to a cathode ray tube 12 via an amplifier 11. The cathode ray tube 12 includes the X direction and Y direction deflectors 7X,
Since the X and Y scanning signals are sent from the scanning signal generating circuit 13 in synchronization with the supply to 7Y, a charged particle image of the sample is displayed on the screen of the cathode ray tube.

Now, the energizing voltage V set by the acceleration voltage setter 25
o-, a voltage corresponding to the accelerating voltage Va- from the adder circuit 31, and a sample applied voltage setting circuit °2.
The voltages corresponding to the sample applied voltage Vs- set in step 6 are converted into digital signals by AD converters 33, 32, and 34, respectively, and sent to the character signal generation circuit 35. As in the ion beam device mode described above, the display screen of the display device displays the charged particle image of the sample as well as the voltages corresponding to the energizing voltage Vo +, acceleration voltage Va-, and sample applied voltage Vs-. (In this case, - indicates the polarity command from the polarity switching command circuit 36) and is displayed numerically.

Therefore, when a photograph is taken from the screen, the charged particle image of the sample is included in the photograph along with the energizing voltage V at the end.

The accelerating voltage Va'' and the voltage corresponding to the sample applied voltage Vs- are shown numerically together with their polarities (- in this case).

FIG. 2 shows another embodiment, in which the above-mentioned
Items with the same numbers as those used in the figures represent the same components. In this embodiment, the accelerating voltage setting system and sample applied voltage setting system are digitalized.

In the figure, 14-. 15- is an accelerating voltage generation circuit, a sample applied voltage generation circuit, 38.39 is a rotary encoder, 40.41 is an up/down counter, 42.43 is a DA converter, 44, 45.46 are each an energizing voltage display,
Acceleration voltage indicator and sample applied voltage indicator. For example, when the rotary encoder is turned to the right, the number of up pulses corresponding to the amount of rotation is sent to the up/down counter, and when turned to the left, the number of down pulses corresponding to the amount of rotation is sent to the up/down counter. The up-down counter is an up-pulse from the rotary encoder,
Increase/decrease count value with down pulse.

The operation in the ion beam device mode will be described below.

First, only at the beginning, the rotary encoder 38 is used to set the energizing voltage Vo to the up/down counter 4o. Thereafter, the rotary encoder 38 is not operated except for the initial setting when changing the magnitude of the energizing voltage. In this state, considering the magnitude of the accelerating voltage, the sample applied voltage Vs is set in the up/down counter 41 using the rotary encoder 39. The output of the up-down counter 4o is sent to the adder circuit 31.
The output is sent to the adder circuit 31 and the DA converter 43.

The adding circuit 31 adds the voltage value corresponding to the energizing voltage Vo and the voltage value corresponding to the sample applied voltage VS, and sends the added voltage value, that is, the voltage value corresponding to the acceleration voltage to the DA converter 42. send. The output of each DA converter 42.43 is input to an error amplifier 27.28. The subsequent operation is performed in the same manner as the operation explained in FIG.
) is generated, and a sample applied voltage Vs of positive polarity is generated from the sample applied voltage generation circuit 15'. Then, the sample 9 is irradiated with ions energized with energy corresponding to the difference Vo between the accelerating voltage (Vo+Vs) and the sample applied voltage Vs.

Now, the voltage corresponding to the energizing voltage vO set by the rotary encoder 38, the voltage corresponding to the accelerating voltage Va from the adder circuit 31, and the voltage corresponding to the sample applied voltage Vs set by the rotary encoder 39 are An energizing voltage indicator 44 and an accelerating voltage indicator 45, respectively. The signal is sent to the sample applied voltage display 46 and the character signal generation circuit 35.

Therefore, each energizing voltage indicator 44. Acceleration voltage indicator 45.
The sample applied voltage display 46 shows an energizing voltage, an accelerating voltage, and
The voltage value corresponding to the voltage applied to the sample is displayed numerically together with its polarity (in this case, according to the polarity command from the polarity switching command circuit 36), and furthermore, the display screen of the display device 12 shows the charged particles in the center of the sample. The image is
, the voltage value corresponding to the sample applied voltage Vs is displayed numerically together with its polarity (+ in this case). When a photo is taken from the screen, the photo includes a charged particle image of the sample.
Biasing voltage ■0 at the end, accelerating voltage Va, sample applied voltage Vs
The voltage corresponding to is mapped numerically along with its polarity (+ in this case).

In addition, in the above-mentioned FIG. 2, the addition circuit 31 is provided between the up-down counter 40 and the DA converter 42, but instead, the addition circuit 31 is provided between the up-down counter 41 and the DA converter
A subtraction circuit is provided between the rotary encoder 39
Set the energizing voltage VO in the up-down counter 41 with
Furthermore, the outputs of the up/down counter 41 may be sent to the subtraction circuits. Then, the subtraction circuit can calculate the voltage corresponding to the accelerating voltage Va and the energizing voltage V.
The voltage value corresponding to o is subtracted, and the difference voltage value, that is, the voltage value corresponding to the voltage applied to the sample, is sent to the DA converter 43, and the outputs of the respective DA converters 42 and 43 (respectively, The acceleration voltage VA corresponds to the sample applied voltage Vs) is input to the error amplifiers 27 and 28.

Next, when switching to electron beam device mode, the first
This process is carried out in the same manner as explained in the figure, so no special explanation will be given.

[Effects of the Invention] The present invention provides means for switching the polarity of the accelerating voltage generated from the accelerating voltage generating means in response to switching between the ion generating source and the electron generating source, and the accelerating voltage value whose polarity has been switched. Since a part of the display section of the display device is equipped with a mechanism for digital display, if the mode is occasionally switched in the composite charged particle beam device and an image photograph of the charged particles is taken each time, the photograph will be displayed. Since the accelerating voltage value is shown in numbers with polarity, it is easy to tell which mode the photo is in even afterward.

Also, when viewing a charged particle image on a display device, you can immediately tell which mode it is in.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a composite charged particle beam device shown as one embodiment of the invention, and FIG. 2 is a schematic diagram of a composite charged particle beam device shown as another embodiment of the invention. 1: Ion source 2: Electron source (electron gun) 3.4; Focusing lens 5: Deflector 6 Near vacuum plate 7X, 7
Y: X direction, Y direction Deflector 8: Objective lens 9: Sample (target) 10: Charged particle detector 11: Ambient 12: Display device 13: Scanning signal generation circuit 14.14
-: Accelerating voltage generation circuit 15.15: Sample applied voltage generation circuit 16: DC power supply 17.18: Oscillation drive circuit 19.20: Step-up transformer 21.22: Rectification and ripple removal circuit 23, 24: Voltage detection resistor 25: Accelerating voltage setting device 26: Sample voltage setting device 2
7.28: Error amplifier 29, 30: Polarity switching circuit
31: Adder circuit 32. 33, 34 two AD converters
35: Character signal generation circuit 36: Polarity switching command circuit 37: Source switching circuit 38. 39: Rotary encoder - 40° 41 Near sub-down counter - 42, 4
3: DA converter 44: Energizing voltage indicator 45: Accelerating voltage indicator 46: Sample applied voltage indicator Patent applicant JEOL Ltd.

Claims (1)

[Claims] Accelerating voltage generating means configured to be capable of switching between an ion source and an electron source, and applying a voltage to the switched source to accelerate the charged particle beam from the source toward the target; A lens system that focuses the charged particle beam and irradiates it onto the target, means for scanning the target with the charged particle beam, means for detecting charged particles generated from the target by the scanning, and a charged particle beam from the target. In a composite charged particle beam device having means for displaying a target image based on the above, means for switching the polarity of the accelerating voltage generated from the accelerating voltage generating means in response to switching between the ion generating source and the electron generating source, and the polarity. A composite charged particle beam device comprising a mechanism for digitally displaying the switched acceleration voltage value along with the polarity on a part of the display section of the display device.