JP2000133185A - Deflector and charged-particle beam device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deflector generating almost no deflection chromatic aberrations. SOLUTION: In an electrostatic and electromagnetic superimposed type deflector 11, the deflection electrodes 12a, 12b of the electrostatic deflector are given voltages of different polarities and of the same magnitude by power supply devices 14a, 14b. The deflection coils 13a, 13b of the electromagnetic deflector are connected in series with each other and given currents by a power supply device 14c, whereby an electric field pointed in the direction of the hatching arrow is generated depending on the electrostatic deflector. When a charged- particle beam is an electron beam, it is deflected in the direction opposite to the black arrow. A magnetic field as indicated by void arrows is generated depending on the electromagnetic deflector. Thus when the charged-particle beam is an electron beam, it is deflected in the direction of the black arrow. By holding constant the strength ratio of the electrostatic deflector to the electromagnetic deflector, the chromatic aberrations of the electrostatic deflector and the electromagnetic deflector cancel out each other and no chromatic aberrations are generated as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflector used in a charged particle beam apparatus such as a charged particle beam exposure apparatus, and a charged particle beam apparatus using the same. Deflector with simple power supply,
And a charged particle beam apparatus using the same.

[0002]

2. Description of the Related Art In a charged particle beam exposure apparatus, a deflector is used to transfer a pattern at a predetermined position on a mask to a predetermined position on a sample such as a wafer. Further, as a lens for the charged particle beam, an electromagnetic or electrostatic superimposed Q lens in which an electrostatic Q lens and an electromagnetic Q lens are combined is used. Such an electromagnetic and electrostatic superimposed Q lens has a characteristic that chromatic aberration is small as a result of canceling out chromatic aberrations of the electromagnetic Q lens and the electrostatic Q lens. FIG. 4 shows an example of a charged particle beam using such an electrostatic and electromagnetic superimposed Q lens and a deflector. In FIG. 4, a charged particle beam 2 emitted from a charged particle source 1 irradiates a mask 4 by an irradiation lens 3. The pattern to be transferred is usually formed on the mask 4 as an opening formed in a thin film. The X-axis component of the trajectory of the charged particle beam passing through the pattern of the mask 4 is indicated by 5x (solid line), and the Y-axis component is indicated by 5y (dashed line). The charged particle beam is the first Q lens 6
a, the image of the mask 4 is formed on the sample 7 by the second Q lens 6b and the third Q lens 6c. At this time, the imaging position on the sample 7 is determined by the deflector 8. Deflector 8
For example, an electrostatic deflector or an electromagnetic deflector is used.

FIG. 5 shows a view of an X-direction deflector viewed from a direction in which a charged particle beam is incident. (A) is an electrostatic deflector,
(B) is an electromagnetic deflector. Although not shown in the figure, Y
The directional deflector turns these 90 degrees around the optical axis. Considering electrons as an example of charged particles,
In FIG. 5A, a positive voltage is applied to the electrode 31a by the power supply 32a to deflect the electron trajectory in the positive X-axis direction.
A negative voltage may be applied to the electrode 31b by the power supply 32b. As a result, an electric field like a hatched arrow is generated, and the electron beam is deflected in the black arrow direction.

In FIG. 5B, coils 33a and 33b of two magnetic poles are connected in series, and a current is supplied to these coils from a power supply 32c to generate a magnetic field in the same direction. In (B), when a magnetic field is applied in the direction of the white arrow in the figure, a force is applied to the electrons in a black solid direction, and the electron trajectory is deflected in the positive X-axis direction.

[0005]

However, such a conventional deflector as described above has a problem that so-called deflection chromatic aberration cannot be avoided due to non-uniform energy of the charged particle source. .

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a deflector that hardly generates deflection chromatic aberration.

[0007]

A first means for solving the above-mentioned problems is to combine an electromagnetic deflector and an electrostatic deflector, and to determine the amount of deflection by the electromagnetic deflector and the amount of deflection by the electrostatic deflector. Is set so as to cancel out the chromatic aberration generated by the electromagnetic deflector and the chromatic aberration generated by the electrostatic deflector (claim 1).

In this means, the amount of deflection by the electromagnetic deflector and the amount of deflection by the electrostatic deflector are set to values that cancel out the chromatic aberration caused by the electromagnetic deflector and the chromatic aberration caused by the electrostatic deflector. Therefore, there is almost no deflection chromatic aberration. In this case, the electromagnetic deflector and the electrostatic deflector need not necessarily be on the same plane.

[0009] A second means for solving the above-mentioned problems is as follows.
In the first means, the amount of deflection when the charged particle beam is deflected by the electromagnetic deflector is x _mo , and the amount of change in the deflection position when the acceleration voltage of the charged particle beam is changed by Δφ _m in that state is Δx _m
When the amount of deflection when the charged particle beam is deflected by the electrostatic deflector is x _eo and the change in the deflection position when the acceleration voltage of the charged particle beam is changed by Δφ _e in that state is Δx _e , The ratio of the deflection width x _e of the deflector to the deflection width x _m of the electromagnetic deflector is x _e / x _m = − (Δx _m / Δφ _m / x _mo ) / (Δx _e / Δφ _e / x _eo )… ( 1) It is set so as to satisfy the following relationship (claim 2).

[0010] In this section, the ratio of deflection width x _m by the deflection width x _e and the electromagnetic deflector according to the electrostatic deflector, since it is set so as to satisfy the equation (1) relationship, and the electrostatic deflector The chromatic aberration with the electromagnetic deflector cancels out, and the deflection chromatic aberration is almost completely eliminated as a whole. Also in this case, the electromagnetic deflector and the electrostatic deflector need not necessarily be on the same plane.

A third means for solving the above-mentioned problem is as follows.
In the first means, the on-axis deflection magnetic field distribution of the electromagnetic deflector and the on-axis deflection electric field of the electrostatic deflector become substantially the same, and the deflection width of the electromagnetic deflector is substantially equal to the deflection width of the electrostatic deflector. The intensity of the electromagnetic deflector and that of the electrostatic deflector are set so as to be doubled and the directions of these deflections become opposite to the optical axis (claim 3).

When the axial deflection magnetic field distribution of the electromagnetic deflector and the axial deflection electric field of the electrostatic deflector are substantially the same, the chromatic aberration of the electromagnetic deflector and the electrostatic deflector becomes 2: Occurs at a rate of 1. In this means, the deflection width of the electromagnetic deflector is almost twice the deflection width of the electrostatic deflector, and these deflection directions are adjusted so as to be opposite to the optical axis. Chromatic aberration between the deflecting device and the electromagnetic deflector cancels out, and almost no deflection chromatic aberration as a whole.

A fourth means for solving the above-mentioned problem is as follows.
Any one of the first means to the third means, wherein a current and a voltage are supplied from the same power source to an electromagnetic deflector and an electrostatic deflector constituting one electromagnetic superposition deflector. (Claim 4).

In the present means, only one power source is required, which is required about three in the past, and the manufacturing cost can be reduced accordingly.

[0015] A fifth means for solving the above problems is as follows.
In the fourth means, two coils constituting an electromagnetic deflector are connected in series, and further, a resistor is connected in series to these coils, and a voltage across the resistor is directly or indirectly applied. It is provided to an electrostatic deflector (claim 5).

In this means, the current flowing through the coils of the electromagnetic deflector is passed through resistors connected in series to these coils, and the voltage generated across the resistors is directly or indirectly used to construct the lens. To be supplied to an electrostatic deflector. Directly means supplying this voltage to the electrodes of the electrostatic deflector as it is, and indirect means supplying it via an amplifier or the like. This eliminates the need for a special power supply for the electrostatic deflector in the case of direct supply, and requires only a small number of power supplies even in the case of supply via an amplifier or the like. Also, since the current flowing through the electromagnetic deflector and the voltage applied to the electrodes of the electrostatic deflector become proportional, the intensity ratio between the electromagnetic deflector and the electrostatic deflector can be kept constant by simple means. Can be

A sixth means for solving the above-mentioned problem is:
In the fifth means, the resistor comprises two resistors connected in series, a high voltage side of the resistor is connected to one of the electrostatic deflectors, and a low voltage side of the resistor is connected to the static side. The electric deflector is connected to the other end, and an intermediate point between the two resistors is connected to a reference voltage (claim 6).

According to this means, the voltage generated between both ends of one of the two resistors is set to + with respect to the reference voltage.
And a voltage generated at both ends of the other resistor can be supplied to the other of the electrostatic deflectors as a negative voltage with respect to a reference voltage. Therefore, if the resistance values of the two resistors are the same, the voltages applied to the two sets of electrostatic deflectors can have the same absolute value and opposite signs, and And the intensity ratio of the electrostatic deflector and the electrostatic deflector can be kept constant.

A seventh means for solving the above problem is as follows.
The fifth means, comprising a voltage amplifier having substantially the same gain for amplifying a voltage across the resistor, wherein the output of one voltage amplifier is connected to one of the electrostatic deflectors and the other The output of the voltage amplifier is connected to another of the electrostatic deflectors as a reverse voltage (claim 7).

In this means, the voltage across the resistor connected in series to the coil of the electromagnetic deflector is amplified by two amplifiers having substantially the same gain, and their outputs are reversed in polarity to obtain an electrostatic capacitance. It is supplied to each electrode of the deflector. Therefore, the same function and effect as those of the sixth means can be obtained, but in this case, the resistance value of the resistor connected in series to the coil of the electromagnetic deflector can be reduced to reduce power consumption. it can. On the other hand, there is a disadvantage that a power supply for an amplifier is required as compared with the sixth means, but the intensity ratio between the electromagnetic deflector and the electrostatic deflector is kept constant by simple means. This is better than having separate power supplies for the electromagnetic deflector and the electrostatic deflector.

Eighth means for solving the above-mentioned problem is:
The fifth means, wherein the resistor has two resistors connected in series, and includes a voltage amplifier having substantially the same gain for amplifying a voltage across each resistor, and one resistor. The output of the voltage amplifier is connected to one of the electrostatic deflectors, and the output of the other voltage amplifier is connected to the other of the electrostatic deflector (claim 8).

In this means, the voltage across each of the two resistors is amplified by an amplifier and supplied to the electrostatic deflector.
The operation and effect of the seventh means are provided.

A ninth means for solving the above problem is:
The fifth means to the eighth means, wherein at least one of the resistors is a variable resistor (claim 9).

Thus, the ratio of the voltage applied to the two electrostatic deflectors can be adjusted, the ratio of the strength of the electromagnetic deflector to the strength of the electrostatic deflector can be adjusted, and the resistance value can be adjusted by the flowing current. Is changed and a current different from the designed value is generated, it is possible to eliminate chromatic aberration by adjusting the resistance value.

According to a tenth means for solving the above-mentioned problems, the charged particle beam apparatus comprises at least one deflector of any one of the first to ninth means. (Claim 10).

In this means, since a deflector having a small deflection chromatic aberration is used, a charged particle beam device having a small deflection chromatic aberration can be obtained as a whole.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a deflector according to a first embodiment of the present invention. In FIG. 1, 1
Reference numeral 1 denotes an electrostatic / electromagnetic deflector, 12a and 12b denote deflection electrodes of the electrostatic deflector, 13a and 13b denote deflection coils of the electromagnetic deflector, and 14a to 14c denote power supply devices.

FIG. 1 shows the deflector in the X-axis direction as viewed from the incident direction of the charged particle beam.
The electromagnetic superposition deflector 11 is rotated by 90 degrees around the optical axis. This deflector differs from the conventional deflector shown in FIG. 5 in that the deflector is an electrostatic and electromagnetic superposition type deflector 11. The deflection electrodes 12a and 12b of the electrostatic deflector are supplied with voltages having different polarities and the same magnitude by power supplies 14a and 14b.
a and 13b are connected in series, are supplied with current by the power supply device 14c, and generate a magnetic field in the same direction. As a result, an electric field in the direction of the hatched arrow is generated depending on the electrostatic deflector, and when the charged particle beam is an electron beam, the charged particle beam is deflected in the direction opposite to the black solid arrow.
Depending on the electromagnetic deflector, a magnetic field like a white arrow is generated. Therefore, when the charged particle beam is an electron beam, it is deflected in the direction of the black solid arrow. The sum of the amount of deflection by the electrostatic deflector and the amount of deflection by the electromagnetic deflector is the total amount of deflection.

The deflection costs of the electrostatic deflector and the electromagnetic deflector are adjusted as follows. First, as shown in FIG. 2A, current is not supplied to the electromagnetic deflector, and deflection is performed only by the electrostatic deflector. The trajectory of the charged particle at this time is 23, and the position on the image plane 21 is A
It is. Deflection width, that is, the intersection O between the image plane 21 and the optical axis 22
Is the origin, the coordinate a of A is _xeo . Further, the acceleration voltage of the charged particle beam is changed. The orbit at this time is 24
And the position on the image plane is B. When the coordinate of the point B is b, the change (ba) in the deflection width is Δx _e and the changed acceleration voltage is Δφ _e .

Next, as shown in FIG. 2B, no voltage is applied to the electrostatic deflector, and the electrostatic deflector is deflected only by the electromagnetic deflector. The trajectory at this time is 25, and the position on the image plane is C. The deflection width, that is, the coordinate c of the point C is _xmo . Further, the acceleration voltage of the charged particle beam is changed. The trajectory at this time is 26, and the position on the image plane is D. When the coordinates of the point D is d, the change of the deflection width (d-c) and [Delta] x _m, the acceleration voltage is changed Δ
φ _m . When the deflection width of the electrostatic deflector in actual use is x _e and the deflection width of the electromagnetic deflector is x _m , these ratios are expressed as x _e / x _m =-(Δx _m / Δφ _m / x _mo ) / (Δx _e / Δφ _e / x _eo ) Adjustment control is performed so as to maintain (1). As a result, the chromatic aberration of the electrostatic deflector and the electromagnetic deflector cancel each other, and
Chromatic aberration does not occur as a whole of the electromagnetic superposition type deflector 11.

[0031] If the electrostatic deflector and an electromagnetic deflector axial deflection field distribution substantially similar to, I'll adjust controlled to be _{x e / x m = -1 /} 2 ... (2). For example, if the deflection position is confirmed by deflecting in one direction by electrostatic deflection, the voltage of the electrostatic deflection is reversed, and the electromagnetic deflection is adjusted to the deflection position of only the first electrostatic deflection, the expression (2) The relationship is satisfied, resulting in a deflection trajectory in which chromatic aberration has been canceled.

FIG. 3 is a schematic view of a deflector according to a second embodiment of the present invention. 3, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 2, reference numeral 14 denotes a power supply device, 15a, 1
5b is a resistor.

The power supply 14 supplies a constant current to excite the deflection coil of the electromagnetic deflector. For example, when the current is in the positive direction,
In the deflection coil 13a of the electromagnetic deflector, an inward magnetic field is generated from the axis, and in the deflection coil 13b, an outward magnetic field is generated from the axis (the direction of the white arrow in the figure). These fields are reversed. When a magnetic field is generated in the direction of the white arrow in the figure, the electron beam is deflected in the direction of the black arrow.

The current which excites the deflection coil of each deflector flows through the resistors 15a and 15b and returns to the power source 14. A voltage is generated across the resistors 15a and 15b by the flowing current. The wiring from the front side of the resistor 15a is connected to the deflection electrode 12a of the electrostatic deflector, and the wiring from the rear side of the resistor 15b is connected to the electrode 12b of the electrostatic deflector.
And 15b are grounded. As a result, an electric field like a hatched arrow is generated in the electrostatic deflector, and the electron beam is deflected in the direction opposite to the black arrow.

In this example, although grounded, for example, when the voltage of the portion including the deflector of the lens barrel is not the ground voltage, the reference voltage between the resistors 15a and 15b is set to a non-ground voltage. The resistance values of the resistors 15a and 15b are ideally set to the same value, and are selected so that the chromatic aberration caused by the electromagnetic deflector can be corrected by the chromatic aberration of the electrostatic deflector. At this time, practically, chromatic aberration cannot be completely canceled, but most chromatic aberration is corrected. When the resistance value of the resistor changes due to the flowing current and a voltage different from the design value is generated, the resistors 15a and 15b are made variable resistors, and the state is adjusted so that the chromatic aberration can be corrected.

Further, when a voltage is applied from the resistor to the electrode of the electrostatic deflector, the voltage can be adjusted and set by using an amplifier. In this case, the voltages at both ends of the resistors 15a and 15b can be amplified by amplifiers and supplied to the powers 12a and 12b of the electrostatic deflector. Can be separately amplified by two amplifiers, and outputs having different polarities can be given to the powers 12a and 12b of the electrostatic deflector, respectively.

By using the deflector as described above as a deflector for a charged particle beam device, the deflection chromatic aberration of the charged particle beam device can be reduced. For example, a deflector according to the present invention may be used as the deflector 8 shown in FIG.

[0038]

As described above, according to the first aspect of the present invention, the amount of deflection by the electromagnetic deflector and the amount of deflection by the electrostatic deflector are different from the amount of chromatic aberration caused by the electromagnetic deflector. Since the chromatic aberration generated by the electrostatic deflector is canceled, the generated chromatic aberration is almost eliminated.

According to the second aspect of the present invention, the ratio of the deflection width x _e of the electrostatic deflector to the deflection width x _m of the electromagnetic deflector is set so as to satisfy a predetermined relational expression. Chromatic aberration between the deflecting device and the electromagnetic deflector cancels out, and almost no deflection chromatic aberration as a whole.

According to the third aspect of the present invention, the on-axis deflection magnetic field distribution of the electromagnetic deflector and the on-axis deflection electric field of the electrostatic deflector become substantially the same, and the deflection width of the electromagnetic deflector is reduced. Since the intensities of the electromagnetic deflector and the electrostatic deflector are set so that the width becomes almost twice and the deflection directions are opposite to the optical axis. The chromatic aberration cancels out, and the deflection chromatic aberration is almost completely eliminated as a whole.

According to the fourth aspect of the present invention, only one power source is required, which is required about three in the past, and the manufacturing cost can be reduced accordingly.

In the invention according to claim 5, a small number of power supply devices can be used. Also, since the current flowing through the electromagnetic deflector and the voltage applied to the electrodes of the electrostatic deflector become proportional, the intensity ratio between the electromagnetic deflector and the electrostatic deflector can be kept constant by simple means. Can be

In the invention according to claim 6, the intensity ratio between the electromagnetic deflector and the electrostatic deflector can be kept constant.

In the invention according to claim 7 and the invention according to claim 8, the resistance value of the resistor connected in series to the coil of the electromagnetic deflector can be reduced, so that power consumption can be reduced. In addition, the intensity ratio between the electromagnetic deflector and the electrostatic deflector can be kept constant.

According to the ninth aspect of the present invention, it is possible to adjust the ratio of the voltage applied to the two electrostatic deflectors, and to adjust the ratio of the strength of the electromagnetic deflector to that of the electrostatic deflector. Even when the resistance value changes due to the flowing current and a current value different from the design value is generated, the chromatic aberration can be eliminated by adjusting the resistance value.

According to the tenth aspect of the present invention, since a deflector having less deflection chromatic aberration is used, a charged particle beam device having less deflection chromatic aberration can be obtained as a whole.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a deflector according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a relationship between deflection by an electrostatic deflector and deflection by an electromagnetic deflector.

FIG. 3 is a schematic diagram of a deflector according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing an example of the configuration of a charged particle beam exposure apparatus using a Q lens and a deflector.

FIG. 5 is a schematic view showing an example of a conventional deflector.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 charged particle source 2 charged particle beam 3 irradiation lens 4 mask 5x, 5y charged particle beam 6a to 6c Q lens 7 sample 8 deflector 11 electrostatic deflector 12a, 12b ... Deflection electrodes of electrostatic deflectors 13a, 13b. Deflection coils of electromagnetic deflectors 14, 14a to 14c. Power supply devices 15a, 15b.

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[Procedure amendment]

[Submission date] November 5, 1998 (1998.11.
5)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 37/305 H01J 37/305 B H01L 21/027 H01L 21/30 541D 541B

Claims (10)

[Claims] An electromagnetic deflector and an electrostatic deflector are combined, and the amount of deflection by the electromagnetic deflector and the amount of deflection by the electrostatic deflector are caused by chromatic aberration caused by the electromagnetic deflector and by the electrostatic deflector. A deflector set to cancel chromatic aberration. 2. The deflector according to claim 1, wherein the amount of deflection when the charged particle beam is deflected by the electromagnetic deflector is x _mo , and the acceleration voltage of the charged particle beam is changed by Δφ _m in that state. The change in the deflection position is Δx _m , the deflection when the charged particle beam is deflected by the electrostatic deflector is x _eo , and the change in the deflection position when the acceleration voltage of the charged particle beam is changed by Δφ _e in that state To Δx
_{When e} , the ratio of the deflection width x _e by the electrostatic deflector to the deflection width x _m by the electromagnetic deflector is x _e / x _m =-(Δx _m / Δφ _m / x _mo ) / (Δx _e / Δφ _e / _xeo ) A deflector set to satisfy the relationship of (1). 3. The deflector according to claim 1, wherein the on-axis deflection magnetic field distribution of the electromagnetic deflector and the on-axis deflection electric field of the electrostatic deflector are substantially the same, and the deflection width of the deflector is static. The deflector is characterized in that the intensities of the electromagnetic deflector and the electrostatic deflector are set so as to be approximately twice the deflection width of the electro-deflector and to make these deflection directions opposite to the optical axis. . 4. One of claims 1 to 3
13. The deflector according to claim 1, wherein a current and a voltage are supplied from the same power supply to the electromagnetic deflector and the electrostatic deflector constituting one electromagnetic superposition deflector. vessel. 5. The deflector according to claim 4, wherein two coils constituting the electromagnetic deflector are connected in series, and further, a resistor is connected in series with the coils, and both ends of the resistor are connected. A deflector, wherein the voltage is supplied directly or indirectly to the electrostatic deflector. 6. The deflector according to claim 5, wherein the resistor has two resistors connected in series.
Make sure that the high voltage side of the resistor is connected to one of the electrostatic deflectors, the low voltage side of the resistor is connected to the other of the electrostatic deflector, and the midpoint between the two resistors is connected to the reference voltage. Characteristic deflector. 7. The deflector according to claim 5, comprising a voltage amplifier having substantially the same gain for amplifying a voltage across the resistor, wherein the output of one voltage amplifier is the output of the electrostatic deflector. A deflector connected to one and the output of the other voltage amplifier connected to the other of the electrostatic deflectors as a reverse voltage. 8. The deflector according to claim 5, wherein the resistor has two resistors connected in series.
Have a voltage amplifier of approximately the same gain that amplifies the voltage across each resistor, with the output of one voltage amplifier connected to one of the electrostatic deflectors and the output of the other voltage amplifier A deflector connected to the other end of the deflector. 9. A method according to claim 5, wherein
The deflector according to claim 1, wherein at least one of the resistors is a variable resistor. 10. A charged particle beam apparatus comprising at least one deflector according to any one of claims 1 to 9.