JPS62143354A - Deflection circuit - Google Patents

Abstract

PURPOSE:To aim at the promotion of high speed and high accuracy, by installing a deflecting signal generating circuit producing biaxial deflecting signals, having bipolarity, from biaxial position signals and an electrical network with resistively divides these deflecting signals and forms voltage of these deflecting signal to each electrode of a multipolar electrostatic deflecting system. CONSTITUTION:A multipolar electrostatic deflecting system 6, electrostatically deflecting a charged beam with electrodes much more than quadrupoles, for example, eight electrodes is driven. And, biaxial deflecting signals + or -Vx and + or -Vy having bipolarity are formed from biaxial position signals Vx and Vy by a deflecting signal generating circuit. Next, this deflecting signal is resistively divided whereby voltage as the deflecting signal to each electrode of the multipolar electrostatic deflecting system 6 is formed by an electric network. This electric network forms voltage as the deflecting signal to each electrode with electric potential to be secured by resistively dividing potential between these deflecting signals Vx, -Vx, Vy and -Vy and grounding and another electric potential to be secured by resistively dividing potential between these deflecting signals. This voltage is realized by a resistive dividing circuit. Thus, a driving signal to the deflecting system is formed by resistive division on the basis of two sets of biaxial deflecting signals + or -Vx and + or -Vy, so that a drive circuit of the multipolar electrostaitic deflecting system is simplifiable, thus the promotion of high speed and high accuracy are attainable.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a deflection circuit for deflecting a charged beam.

In particular, the present invention relates to a deflection circuit suitable for driving a symmetric multipole electrostatic deflector that electrostatically deflects a charged beam using more than four electrodes at high speed and with high precision.

[Background of the invention]

Conventionally, regarding this type of deflector, the 44th (Autumn 1983) Academic Conference of the Japan Society of Applied Physics, a collection of lecture proceedings.

26p-T-11, an octuplic electrostatic deflector requires eight drive amplifiers, and points out that it is important to develop a deflection method that can reduce the number of drive amplifiers, On the other hand, the two-axis deflection signal X, - having nine polarities
A 20-pole unequally divided cylindrical electrostatic deflector that can be driven only by X, Y, and -Y has been proposed. According to this proposed method, the disadvantage of requiring a large number of drive amplifiers can be solved, but there is a problem in that highly accurate machining and assembly of the deflection electrodes is required. That is, in the multipole deflection method, a drive amplifier for driving each electrode is provided corresponding to each electrode, so that the electrical characteristics are uniform. In other words, offset voltage, drift.

It is necessary to prepare a drive amplifier with low noise.

However, the octupole deflection method allows for non-circuit difference correction in the 'f4j, air circuit, and by solving the above problems, it is easier to manufacture than the 20-pole unevenly divided cylindrical electrostatic deflector. , and attached! It has the advantage of being able to take advantage of the many IF functions.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a drive circuit for driving a multipole deflector that can be easily formed and has high precision.

[Summary of the invention]

In order to achieve the above object, the present invention uses a two-axis position signal V
211tl, which is more bipolar than V y! A deflection signal generating circuit generates deflection signals vX, -Vx, Vx, -v of I, and divides these deflection signals by resistance to generate a voltage as a deflection signal to each 'electrode of a multipole electrostatic deflector. The configuration includes a circuit network to be formed.

[Embodiments of the invention]

Hereinafter, nine embodiments of the present invention will be explained with reference to FIGS. 1 to 6.

FIG. 1 is a block diagram of one embodiment, which is a deflection circuit for driving an octuplic electrostatic deflector. In Figure 1, 1
are position signals vX of two orthogonal axes.

A position signal generation circuit that generates Vy, 2 is this position signal V
Two-axis deflection signal vX with bipolar polarity from Xg V y
, -vX, Vx, and -v, and 3 is a deflection signal generating circuit that generates and outputs these deflection signals ±V a voltage divider circuit for deflection electrodes that produces eight cosine-distributed voltage signals y%~V, / to be supplied to 4;
5 is an amplifier circuit, and 5 is an astigmatism correction voltage signal φ8. A voltage source for astigmatism correction that generates φ2, and 6 are an octuplic electrostatic deflector composed of eight electrodes ① to ②.

In order for the output signal of the deflection electrode voltage divider circuit 3 to have a cosine distribution, the relational expression between the input signal and the output signal is (a) When there is no astigmatism correction ■1'=vx )V,'= (VX
+V, )/TT 1(b) If there is astigmatism correction 7・'=7・su・) v,'=(v,+vy)/Ufuφ2 □v,'=
v, -φ 1V6'=(Vx
Vy)/J2-φ2 1.

Traditionally, these operations are performed by operational amplifiers,
■1'~V'e/ was formed. However, in that case, it is necessary to align the amplification degree, offset, drift, noise level, etc. of the circuit elements within a certain range, which makes the two circuits complicated and expensive.

In order to solve these problems, the present invention realizes equations (1) and (2) using a resistor divider circuit.

First, when formula (1) is realized, if a resistor circuit is constructed as shown in FIG. 2, then (1) to Va' are formed as shown in formula (3) below.

Now, if the resistance values of R and R2 are determined so that they satisfy the relationship of the following equation (4), then 1' becomes the equation (5).

R2=“Σ(R,+R,) (4)■
□'=VX/J# (5) Furthermore, v,=vx/J1. When vy=Vy/41 is introduced, equation (3) is expressed as equation (6) using Vx and v2.

In other words, if a resistor divider circuit as shown in Fig. 2 is used, the deflection sensitivity will be reduced to 1/1 of the normal deflection sensitivity, but by providing the amplifier circuit 4 that multiplies the input signal by 1, the deflection sensitivity will be reduced to 1/1 of the normal deflection sensitivity. Alternatively, ±vX and ±v2 formed by the deflection signal generation circuit 2 can be further
If the deflection signal is amplified by a factor of Σ, the output of the voltage dividing circuit 3 can be directly supplied to each electrode without going through the amplifier circuit 4.

FIG. 3 is an embodiment circuit diagram for realizing equation (2) when there is astigmatism correction, in which the astigmatism correction voltage φ8.・± from φ2
φ8. ±φA are created and these voltages are applied as shown in FIG. 3 with respect to the ground potential in FIG.

The deflection voltage V□'˜V, / in FIG. 3 is expressed by the following equation.

Now, if the resistance values of R□, R2, R, and r are determined so that they satisfy the following equation (8), equation (2) can be realized.

In this case, if R=r, R2/(R1+R2) is “l
/3, and vX and v require a deflection voltage 3/''1 times. Furthermore, if r=GR.

R2/(R1+R2) Halo n/13 Tonari+Vx
and vy can be made smaller than when R=r. Also, φ8. Since φa also has the same relationship as above,
Must be considered in implementation.

The resistor network described above can perform highly accurate calculations by precisely selecting resistance values. Further, by installing the resistors in the same environment, the number of resistors can be reduced compared to the case where a +njL degree drift operational amplifier is used, and higher accuracy can be achieved. Also, in the deflection signal generation circuit 2.

If the configuration is such that the necessary voltage is formed, the amplifier circuit 4
is not required at all, making it possible to create a deflection circuit that is easy to manufacture and inexpensive.

FIG. 4 shows a case of a two-stage deflection drive circuit in which eight-electrode electrostatic deflectors 6' and 6' are connected in series. Usually 2
Since astigmatism is corrected by the 8-electrode electrostatic deflector 6' in the second stage, the voltage divider circuit 3'' for the deflection electrode is equipped with the resistor network 3' shown in Figure 2 and the resistor network 3' shown in Figure 3. Two resistor networks 3'' are used. Thereby, the charged beam 7 can be deflected in paraxial approximation.

Large angle deflection is possible. Although the amplifier circuit 4 is not shown in FIG. 4, the amplifier circuit 4 may be necessary in some cases.
In that case, a similar effect may occur.

This does not depart from the invention.

5 and 6 are circuit diagrams showing examples of phase compensation when an electric capacitor fCa is connected as a load to the resistor network shown in FIG. 2, respectively. When Cd is connected to the load, R-Cd
Responsiveness decreases with a time constant of .

This makes it difficult to apply to drawing devices that require high-speed deflection. To solve this problem, if we add a single-phase compensation capacitor Cct, C, as shown in Figures 5 and 6, and determine Cct and Cβ as quadratic, it becomes exactly the same as a pure resistive load, High-speed deflection can be easily achieved.

In Fig. 5, the transfer function gxcs of HV d/V x
') can be expressed as a quadratic expression using the operator S.

If C3 is determined so that it satisfies the 9th order relationship, the transfer function g(S) becomes only pure resistance.

Phase compensation becomes possible.

In Figure 6 = V a / (V x + V a)
The transfer function g2(S) of is expressed by equation (11), and from this, two-phase compensation becomes possible if CO satisfies the relationship of equation (12).

Cβ = −c, +
(12)
By applying the phase compensation described above to FIG. 3, high-speed deflection can be achieved even in a resistor network having an astigmatism correction function.

Although the example describes the case of an 8-type rod electrostatic deflector, the same effect can be achieved even if this method is applied to other multipole electrostatic deflectors to form a deflection signal. can.

Furthermore, the resistor used in the present invention can be either a single resistor or a module resistor consisting of two sets, but it is preferable to use a module resistor in terms of stability and precision. .

Furthermore, although the aligner function was not explained in the above embodiment, the aligner function can be realized by applying an aligner DC voltage to the two sets of deflection signals ±V x r±vy, which is also a feature of the present invention. This does not deviate from the content.

In addition, in the embodiment, the case where the multipole is 8 poles is taken as an example and explained, but the multipole 9 exceeding 8 poles, for example,
Even in the case of 6 poles, 20 poles, etc., the same structure can be used and the same effect can be produced.

〔Effect of the invention〕

As explained above, according to the present invention, a drive signal to a deflector having more than four electrodes is formed by resistance division based on two sets of biaxial deflection signals ±V x and ±vy. Therefore, there is no need to employ a high-speed, high-precision, high-voltage amplifier that has been used in the past, and the drive circuit for the multipole electrostatic deflector can be simplified, resulting in higher speed and higher precision.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a circuit diagram of an embodiment without astigmatism correction. Fig. 3 is a circuit diagram of an embodiment with astigmatism correction, Fig. 4 is a block diagram of an embodiment in which the present invention is applied to a two-stage deflection system, and Figs. 5 and 6 are high-speed, respectively. FIG. 3 is an example diagram of a phase complement circuit for deflection. Explanation of symbols> 1... Shield signal generation circuit 2... Deflection signal generation circuit 3. 3', 3'... Deflection electrode voltage dividing circuit 4...
Amplifier circuit 5... Stigma correction power supply 6.6', 6
″...Junnosuke Nakamura, patent attorney representing the 8-pole electrostatic deflector''?

Claims (8)

[Claims] (1) In a deflection circuit that drives a multipole electrostatic deflector that electrostatically deflects a charged beam with more electrodes than quadrupole, a two-axis deflection signal V_x having bipolarity from two-axis position signals v_x and v_y, -V_x, V_y, -V_y; and a circuit network that divides the deflection signal by resistance to form a voltage as a deflection signal to each electrode of the multipole electrostatic deflector. A deflection circuit characterized by: (2) the circuitry is configured to transmit the deflection signals V_x, -V_x,
A voltage as a deflection signal to each of the electrodes is formed by a potential obtained by resistively dividing the potential between V_y, -V_y and the ground, and a potential obtained by resistively dividing the potential between the respective deflection signals. A deflection circuit according to claim 1. (3) The deflection circuit according to claim 1, wherein the circuit network includes a voltage source for correcting astigmatism of a charged beam. (4) The deflection circuit according to any one of claims 1 to 4, wherein the output of the circuit network is directly connected to an electrode of the multipole electrostatic deflector. (5) The resistance value of each resistor in the circuit network is selected so that the absolute voltage value of the deflection signal is always not smaller than the output voltage of the circuit network. The deflection circuit according to any one of items 1 to 4. (6) The deflection according to any one of claims 1 to 4, wherein the load of the circuit network is a capacitor load, and the circuit network includes a capacitor for phase compensation. circuit. (7) The deflection circuit according to any one of claims 1 to 4, wherein the resistance of the circuit network is constituted by a module resistor. (8) The deflection circuit according to any one of claims 1 to 4, wherein each resistor of the circuit network is installed in the same environment.