JP2000260382A - Charged particle beam equipment - Google Patents

Abstract

(57) [Problem] To provide an alignment and blanking mechanism capable of obtaining high-speed blanking and high voltage stability. During a blanking-off period, a switch (24S) of a switching element (24) is turned off, and an electrode (2) is turned off.
The applied voltage to 0A is 0 volt. The electrode 20B has-
A voltage of 2 Va volts or +2 Va volts is applied. The electron beam 27 passes through the restriction aperture 21 and reaches the target. During the blanking-on period, the switch 24S of the switching element 24 is turned on, and the voltage (2 Vb volts) from the positive power supply 22 is applied to the electrode 20A. A voltage of -2 Va volt is applied to the electrode 20B. The electron beam 27 is deflected to the side of the electrode 20A, and is blocked from passing in the target direction by the restriction aperture 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a charged particle beam apparatus provided with a blanking mechanism.

[0002]

2. Description of the Related Art An electron beam writing apparatus is an apparatus which draws a predetermined pattern at a predetermined position on a material to be drawn by shot with an electron beam at a predetermined position on the material to be drawn. It is in the spotlight.

Further, a scanning electron microscope for observing, inspecting, or measuring the length of a semiconductor device or the like based on a material to be drawn on which a semiconductor device or the like is formed as a sample and scanning the sample with an electron beam. However, they have become indispensable in the semiconductor fabrication process.

[0004] In such a charged particle beam apparatus such as an electron beam lithography apparatus or a scanning electron microscope, a high-speed operation is performed so that a beam is not irradiated onto a material or a sample (hereinafter referred to as a target) unless necessary. The beam is blocked (blanked).

FIG. 1 shows an example of a blanking mechanism of an electron beam apparatus. In FIG.
The blanking electrodes 2 and 2 are disposed opposite to each other with a limiting aperture. 3 is a positive voltage source, 4 is a negative voltage source,
Reference numerals 5 and 6 denote resistors. Switching elements 7 and 8 are connected between the positive voltage source 3 and the resistor 5 and the negative voltage source 4 and the resistor 6, respectively.

In such a blanking mechanism, a blanking signal as shown in FIG. 2 is supplied to the switching elements 7 and 8 to turn on (non-block) and off (block) a beam onto a target (not shown). It is carried out. That is, a low period of the blanking signal (a period of blanking off),
Since the switches 7S and 8S of the switching elements 7 and 8 are turned off, the voltages from the positive voltage source 3 and the negative voltage source 4 are not applied to the blanking electrodes 1A and 1B, respectively. Therefore, the voltage applied to the blanking electrodes 1A and 1B becomes 0 volt, and the electron beam 9 from the electron source (not shown) passes through the limiting aperture 2 and passes through the target (not shown) as shown by a solid line. ). Further, during a high period of the blanking signal (a blanking-on period), the switches 7S and 8S of the switching elements 7 and 8 are turned on, and the voltages from the positive voltage source 3 and the negative voltage source 4 + Vb volts and -Vb The bolts are respectively blanking electrodes 1A
1B. Therefore, a large blanking voltage (2 Vb volt) is applied between these electrodes, and an electron beam 9 from an electron source (not shown) is applied.
Is deflected to the electrode 1A side as shown by the dotted line, and the passage toward the target (not shown) is blocked by the restricting aperture 2. Usually, a transistor or the like is used as the switching element, and the beam is turned on and off at a very high speed as described above.

[0007] A charged particle beam apparatus is usually provided with a lens such as a focusing lens, and the electron beam is usually aligned so as to pass through the axial center of the lens. That is, apart from the blanking mechanism, an alignment mechanism (not shown) is provided around the optical axis O, and a target (not shown) is formed at an angle with respect to the optical axis O.
The electron beam traveling toward the optical axis O is deflected (aligned) so as to pass through the optical axis O. Incidentally, such an alignment mechanism includes, for example, two counter electrodes which are arranged opposite to each other in the X and Y directions with the optical axis O interposed therebetween, and an appropriate voltage is applied between the electrodes in each direction. What is done is common.

However, providing a blanking mechanism and an alignment mechanism as described above not only requires a large space but also significantly increases costs. Further, at least six electrodes are required, which leads to an increase in noise.

[0009]

FIG. 3 shows an example of an alignment and blanking mechanism which solves these problems and which enables the alignment mechanism to perform blanking. That is, this is a mechanism of a system in which the alignment voltage and the blanking voltage are superimposed on the alignment electrode.

In FIG. 1, reference numerals 10A and 10B denote electrodes for alignment and blanking which are opposed to each other with the beam optical axis O interposed therebetween.
11 is a restriction aperture. 12 is a variable voltage source, 13 is a positive voltage source, 14 is a switching element, and 15 is an adder. A non-inverting amplifier 16 and an inverting amplifier 17 are connected between the adder and the electrodes 10A and 10B, respectively. Although only the electrodes 10A and 10B are shown in FIG. 3, the alignment is required in the X and Y directions. Therefore, if the electrodes 10A and 10B are used for the X direction alignment, the Y direction alignment is actually performed. And a variable voltage source for applying an alignment voltage to these electrodes.

In such an alignment and blanking mechanism, a blanking signal as shown in FIG. 2 is supplied to the switching element 14 to turn on (non-block) and off (block) a beam onto a target (not shown). It is carried out.
That is, the switch 14S of the switching element 14 is turned off during the low period of the blanking signal (the blanking off period), and the voltage Va from the variable power supply 12 is supplied via the non-inverting amplifier 16 and the inverting amplifier 17, respectively. The voltage is applied to the alignment and blanking electrodes 10A and 10B. That is, + Va,
A voltage of -Va volt or -Va, + Va is applied. Therefore, a voltage of 2 Va volts is applied between these electrodes. This voltage (2Va) is an alignment voltage and is a small voltage. By controlling the variable voltage source 12 according to the deviation of the electron beam from the optical axis O, the positive and negative and absolute value of the voltage Va are controlled. The electron beam is aligned by the control. Accordingly, the electron beam 18 from the electron source (not shown) passes through the limiting aperture 11 and reaches the target (not shown) as shown by the solid line.

Also, during a high period of the blanking signal (blanking-on period), the switch 14S of the switching element 14 is turned on, and the voltage Va from the variable voltage source 12 and the voltage Vb from the positive voltage source 13 are switched. The voltage (Va + Vb) volt to which the voltage is added is applied to the alignment and blanking electrodes 10A and 10B via the non-inverting amplifier 16 and the inverting amplifier 17, respectively. That is, the electrode 1
0 (Va + Va) volts,-
A voltage of (Va + Va) is applied. Therefore, a voltage of 2 (Va + Vb) volts is applied between these electrodes. Vb
Is an extremely large voltage, usually Va≪Vb, so that the electron beam 19 from an electron source (not shown) is deflected to the electrode 10A side as shown by a dotted line by the blanking voltage 2Vb, The passage in the direction (not shown) is blocked. However, in order to perform high-speed blanking in such an alignment and blanking mechanism, a non-inverting amplifier 15, an inverting amplifier 16, and an adder 14 having high frequency characteristics and high response speed are required. Non-inverting amplifiers, inverting amplifiers and adders are very expensive. If an expensive amplifier or the like is used, the stability of the voltage passing through the amplifier or the like having such a high frequency characteristic is impaired, and alignment cannot be performed accurately.

An object of the present invention is to provide a novel charged particle beam apparatus which solves such a problem.

[0014]

Means for Solving the Problems A charged particle beam apparatus according to the present invention has a charged particle beam generation source, and is capable of irradiating a predetermined position on a target with a charged particle beam from the generation source. In a charged particle beam device,
At least one pair of electrodes is disposed between the charged particle generation source and the target with the optical axis interposed therebetween, and a voltage for blanking based on a blanking signal including a blanking on / off signal is applied to one of the electrodes. To the other electrode,
A blanking mechanism for applying a voltage for alignment is provided.

The charged particle beam apparatus according to the present invention is provided with a switch that is turned on and off based on a blanking on / off signal of a blanking signal.
A blanking voltage is applied to one of the electrodes based on the OFF state.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 4 shows an example of an alignment and blanking mechanism which is a main part of the charged particle beam apparatus according to the present invention.

In the figure, reference numerals 20A and 20B denote electrodes which are arranged to face each other with the beam optical axis O interposed therebetween, and reference numeral 21 denotes a limiting aperture.
22 is a positive voltage source, 23 is a resistor, and the positive voltage source 22 and the resistor 2
3, a switching element 24 is connected. 2
Reference numeral 5 denotes a variable voltage source, and an inverting amplifier 26 is connected between the variable power supply 25 and the electrode 20B. As described above, since the alignment is required in the X and Y directions,
Although only the electrodes 20A and 20B are shown, actually,
Assuming that the electrodes 20A and 20B are for X-direction alignment, a pair of electrodes for Y-direction alignment and a variable voltage source for applying an alignment voltage to these electrodes are provided.

In such a mechanism, the amplification factor of the inverting amplifier 26 is previously set to twice. The positive power supply 22 is set so that its output voltage becomes a blanking voltage (2 Vb volts).

In this state, the switching element 24
2 to supply a blanking signal as shown in FIG. 2 to turn on (non-blocking) and turn off (blocking) a beam onto a target (not shown).

That is, during the low period of the blanking signal (the blanking off period), the switch 24S of the switching element 24 is turned off, and the voltage applied to the electrode 20A becomes 0 volt. At this time, the voltage +
Since Va volt or -Va volt is applied to the electrode 20B via the inverting amplifier 26, a voltage of -2Va volt or + 2Va volt is applied to the electrode 20B. This voltage is the same voltage between the electrodes as at the time of blanking off in the mechanism of FIG. 3, and this alignment voltage (2 Va) controls the variable voltage source 25 in accordance with the deviation of the electron beam from the optical axis O. By doing so, the positive / negative and absolute values are controlled, so that the electron beam is aligned. Therefore, the electron beam 27 from the electron source (not shown) is, as shown by the solid line,
Target (not shown) passing through restriction aperture 21
To reach.

During the high period of the blanking signal (the blanking-on period), the switch 24S of the switching element 24 is turned on, and the positive power supply 22 is connected to the electrode 20A.
(2 Vb volts). At this time, since a voltage of + Va volt from the variable power supply 25 is applied to the other electrode 20B via the inverting amplifier 26, a voltage of -2Va volt is applied to the electrode 20B. Therefore, a voltage of 2 (Va + Vb) volts is applied between these electrodes. This voltage is the same as the voltage at the time of blanking ON in the case of the mechanism of FIG. 3 described above, and is generally Va≪Vb. Therefore, the electron generating source (not shown) is generated by the blanking voltage 2Vb.
The electron beam 27 is deflected toward the electrode 20A as shown by the dotted line, and is blocked from passing in the direction of the target (not shown) by the restriction aperture 21.

With the above arrangement, blanking is performed at a high speed, and it is not necessary to increase the frequency characteristics of the inverting amplifier 26, so that the voltage stability is not impaired.

Although the above embodiment has been described by taking an electron beam apparatus as an example, it is needless to say that the present invention can be applied to an ion beam apparatus such as a focused ion beam apparatus.

[Brief description of the drawings]

FIG. 1 shows an example of a blanking mechanism of a conventional electron beam device.

FIG. 2 shows an example of a blanking signal.

FIG. 3 shows an example of another blanking mechanism of a conventional electron beam device.

FIG. 4 shows an example of a blanking mechanism of the electron beam device of the present invention.

[Explanation of symbols]

 O ... optical axis 20A ... electrode 20B ... electrode 21 ... limit aperture 22 ... positive voltage source 23 ... resistor 24 ... switching element 24S ... switch 25 ... variable voltage source 26 ... inverting amplifier 27 ... electron beam

Claims (2)

[Claims] 1. A charged particle beam apparatus having a charged particle beam generation source, wherein a charged particle beam from the generation source can be irradiated to a predetermined position on a target. At least one pair of electrodes is disposed opposite to each other with the optical axis therebetween, and a voltage for blanking based on a blanking signal including a blanking on / off signal is applied to one electrode, and a voltage is applied to the other electrode. A charged particle beam device comprising a blanking mechanism for applying an alignment voltage. 2. A blanking signal of a blanking signal,
2. The charged particle according to claim 1, wherein a switch for turning on and off based on an off signal is provided, and a voltage for blanking is applied to one of the electrodes based on on and off of the switch. Beam device.