JPH01261822A - Charged particle beam lithography device - Google Patents

Abstract

PURPOSE:To obtain uniform beam irradiation amount without increasing the number of bits of a D/A converter by a method wherein the position of beam irradiated on a material is specified by a main deflection output unit and a spot beam is scanned by a sub-deflection output unit in two dimensional (x) and (y) directions with respect to each irradiation position as the center. CONSTITUTION:Pattern data to be exposed is transferred from a CPU 1 to a deflector control unit 2. This pattern data is given to an (x) main deflection output unit 3 and a (y) main deflection output unit 5 from the deflector control unit 2. As a result, conventional spot coordinate points are set on the respective beam irradiation points based on the outputs of the (x) and (y) main deflection output units. On the other hand, control signals are output from a subscan control unit 8 to an (x) sub-deflection output unit 4 and a (y) sub-deflection output unit 6, respectively according to timing for irradiating the one conventional spot, synchronized with pulses generated by a reference pulse generator 7. By partition exposing conventional exposure scanning steps in one-shot units, irradiation amount of ions is made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a charged particle beam lithography apparatus, and more particularly to a charged particle beam lithography apparatus capable of obtaining a uniform beam irradiation amount.

[Prior Art] [In a single particle beam device, such as a focused ion beam device, when ions are directly implanted into a material, the ion beam is controlled by a deflector to direct the ions to a predetermined location on the material. I'm typing. In this case, the channel effect (an annulus where the incident ions penetrate deep into the material)
In order to suppress this, the material is irradiated with the ion beam at an angle of incidence of about 7 degrees with respect to the optical axis.

When implanting ions into a material, the amount of ions implanted per unit area of the material surface is an important issue. The ion implantation darkness is determined by the spot beam diameter of the ion beam, the step amount of the beam when controlling the irradiation beam position with a deflector, and the irradiation time. FIG. 5 is a diagram showing the relationship between the ion beam implantation time and the step (ion implantation time). In the figure, (a) shows the case of implantation in step d, and the vertical axis direction indicates the implantation amount for one spot. (B) shows the case where the drive is performed at step d/2, and (C) shows the case where the drive is performed at step d/4.

As is clear from the figure, when the beam position is changed as shown in the figure with respect to the distribution of the ion implantation amount of the spot beam at one point, the total ion implantation amount changes as shown in the figure. In other words, as shown in (a), if the step interval is large, the implantation will be uneven in places. On the other hand, when the step interval is shortened as in (b) and (c), the total ion implantation amount becomes uniform locally as shown in the figure. In other words, it has been found that if the beam diameter is the same, the implantation effect becomes more uniform when the distance between positional changes (step amount) is made smaller.

[Problems to be Solved by the Invention] However, in the conventional technology, in order to reduce the position change interval, the number of control bits of the D/A transformer controlling the deflector must be increased. Since the A/A converter with a large number of bits is extremely expensive and has an extremely slow hardware conversion speed, there is a limit to how small the interval between position changes can be made.

The present invention was made in view of these problems, and its purpose is to realize a charged particle beam lithography device that can obtain a uniform irradiation amount without increasing the number of bits of the D/A converter. It's about doing.

[Means for Solving the Problems] The present invention, which solves the above-mentioned problems, uses a vJ electric powder particle beam drawing apparatus that irradiates a spot beam onto a material to obtain a predetermined pattern. A main deflection output device and a sub-deflection output device are provided to drive each deflector, and the main deflection output device sets the beam irradiation position on the material.
x, y2 centered on each irradiation position with the sub-deflection output device
It is characterized by being configured to scan the spot beam in the dimensional direction.

Effect] By dividing the same irradiation time into multiple parts and increasing the number of steps with a finely focused beam spot according to the division, the uniform beam irradiation interval is increased by 1q. In other words, what was conventionally scanned as shown in FIG. 6(A) is now irradiated with a thin spot beam divided into multiple parts as shown in FIG. 6(B).

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is CP[J, and 2 is a deflector i! which receives drawing data from the CPU 1 and outputs a drive signal for driving the deflector in each of the X and Y directions. IIJ III
unit, 3 is an output device for X main deflection which receives a deflection signal in the X direction from the deflector control unit 2, 4 is Xf' in the X direction;
Output device for Hi direction output device A y main deflection output device that receives a deflection signal in the y direction from the direction device control unit 2, 6 is a y in the y direction.
This is a sub-deflection output device. As the main deflection output devices 3 and 5, for example, D/A converters are used.

A reference pulse generator 7 generates reference pulses for synchronizing the deflectors in each of the x and y directions, and its output is fed into the deflector control unit 2. 8 receives the outputs of the deflector υ1tlll unit 2 and the reference pulse generator 7, x,
This is a sub-scan controller that provides drive signals to the sub-deflection output devices 4 and 6 in each of the y directions. 9 is an adder for adding the outputs of the X main deflection output device 3 and the X sub deflection output device 4;
0 is a deflector which adds the outputs of the y main deflection output device 5 and the y sub deflection output device 6, and 11 is a deflector to which the outputs of these adders 9 and 10 are applied. The operation of the device configured as described above will be explained as follows.

The present invention solves the unevenness in the amount of ion implantation per unit area that occurs due to the conventional method of drawing patterns with a beam step of a large diameter, as shown in FIG. 6(A), as shown in FIG. 6(B). The conventional single spot is divided into smaller parts to enable uniform ion implantation. First, pattern data to be drawn is transferred from the CPU 1 to the deflector control unit 2. This pattern data is transmitted from the deflector control unit 2 to the X main deflection output device 3゜y.
It is given to the main deflection output device 5. As a result, conventional spot coordinate positions are set at each beam irradiation position on the material, which is set based on the outputs of the x and y main deflection output devices, as shown in FIG. 2(a). Here, soil indicates the center of the coordinate position.

d is a step suspension similar to that described above.

On the other hand, in synchronization with the pulses generated by the reference pulse generator 7, the sub-scan controller 8 outputs the
．． yf? Control signals as shown in FIG. 3 are outputted to the output devices 6 for 1Jffii, respectively.

The example shown in the figure shows a case where the image is divided into 2×2. (
A) shows a control signal in the X direction, and (b) shows a control signal in the X direction. When dividing into 2 x 2, each beam illuminates)! At each position, as shown in FIG. 2 (b), scan with a spot beam of size d/2Xd/2 and an irradiation time of 1/(2X2>).Here, the drawing spot is set in the fourth quadrant. In Fig. 2 (b), the sub-deflection output devices 4 and 6 are used to direct the sub-deflection output devices 4 and 6 in the direction of the arrow at the center of the arbitrary irradiation position of each beam irradiation value on the material set by the main deflector. Subop 1 - The beam is deflected. If the ground is the reference point, in the X direction, see Figure 3.
As shown in b), an amplitude of d/4 is applied in the directions of 1, +, 10, and - for spot periods 1.2 and 3.4, respectively. Specifically, the adder adds the output of the X main deflection output device 3 and the output of the X sub-deflection output device 4, and applies the addition result to the deflector 11.

In addition, regarding the X direction, if the soil is used as a reference, in the case of the X direction, as shown in Figure 3 (b), spot period 1,
d in the direction of -, -9+, and ten for 2 and 3.4, respectively.
Add an amplitude of /4. Specifically, the adder 10 adds the output of the y main deflection output device 5 and the output of the y sub-deflection output device 6, and applies the addition result to the deflector 11. As a result, each beam irradiation position on the material is drawn by a fine spot beam as shown in FIG. 2(b), so that drawing as shown in FIG. 6(b) can be performed. In this case, it goes without saying that the irradiated beam is narrowed (in this case, to d/2Xd/2) by the electron optical system.

As described above, according to the present invention, the conventional one-spot drawing can be divided into four-spot scans. That is, according to the present invention, the total ion implantation width can be made uniform by multi-division. At this time, the X sub-deflection output device 4. As the y sub-deflection output device 6, an output device with a small number of conversion bits can be used as shown in FIG. It becomes possible to do so.

In the above-mentioned embodiment, the case where one spot is divided into 2×2 was taken as an example, but the invention is not limited to this, and more divisions are also possible. For example, if a control signal as shown in Fig. 4 is outputted from the sub-deflection output device 4.6 in each of the x and y directions, 3 x 3 division as shown in Fig. 2 (c) is possible. . In the case of Fig. 4, by avoiding changing the amplitude of d/6 in the + and - directions as shown in the figure for each of the 9 spot periods, it is possible to divide into 9 as shown in Fig. 2 (C). Become.

In this case, the size of each divided spot is narrowed down to 1/3x1/3, and the irradiation time of each divided spot is 1/(3x3).
done to. Furthermore, the present invention can be similarly applied to further nxn divisions. In addition, in the above-mentioned embodiments, the case of an ion implantation device using a focused ion beam device was mainly taken as an example, but the invention is not limited to this, and other charged particle beam lithography devices such as an electron beam lithography device can be used. It can be applied to However, in the case of ion beam implantation, the Coulomb effect (a phenomenon in which the irradiation area spreads to the surroundings on the material) is smaller than in the case of electron beam lithography, so the effect of making the illumination eJ4ffi uniform by multi-division is large.

[Effects of the Invention] As explained in detail above, according to the present invention, by dividing the conventional drawing scanning step into multiple beam shots, ■ When implanting ions into a material, the ion The implantation m becomes uniform.

■One spot irradiation time is 1/(n
Compared to the case of the prior art, in order to make
The distance between i itself is almost unchanged.

As described above, according to the present invention, bits 1 to ＠ of the D/Δ converter
Uniform beam illumination without increasing the size! ) 111 to 1!
It is possible to realize a charged particle beam lithography device that can perform 7 steps.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention;
Figure 2 shows the split state of the spot beam; Figure 3;
Figure 4 is a diagram showing the output signal waveform of the sub-deflection output device, Figure 5
The figure shows the relationship between the ion beam implantation length and the step (ion implantation time), and FIG. 6 is a comparative diagram of the conventional spot beam method and the spot beam method according to the present invention. 1... CPU 2... Deflector interrogation unit 3... Output device for X main deflection 4... Output device for X sub-deflection 5... Output device for y main deflection 6... Y sub-deflection Output device 7...Reference pulse generator 8...Subscan controller 9.10...Adder 11...Deflector Fig. 3 (A) (2X2 example)
(b) Figure 4 (3x3 examples)

Claims (1)

[Claims] In a charged particle beam drawing device that irradiates a spot beam onto a material to obtain a predetermined pattern, a main deflection output device and a sub-deflection output device are provided for driving deflectors in each of the x and y directions, A charging device characterized in that the main deflection output device sets the beam irradiation position on the material, and the sub-deflection output device scans the spot beam in two-dimensional x and y directions centering on each of the irradiation positions. Particle beam lithography equipment.