JPH03198321A - Charged particle beam lithography equipment - Google Patents

Abstract

PURPOSE:To draw oblique lines with high accuracy without reducing the size of a charged particle beam by providing a pattern memory having such a capacity that can store the information of the peripheral area of an area containing a desired pattern and controlling the irradiating time with the beam after discriminating the oblique lines on the basis of the information of the peripheral area. CONSTITUTION:An oblique line correction circuit 12 compares the information of the peripheral area of an area containing a desired pattern stored in a pattern memory 11 with a reference pattern and, when the pattern stored in the memory 11 coincides with the reference pattern, decides that the pattern is an oblique line. Then the circuit 12 sends a control signal to a blanking electrode 4 through a computer 15 for control so as to control the irradiating time of a sample 8 with a charged particle beam in such a way that picture drawing is made during a half of scanning time and no picture drawing is made during the other half. Therefore, oblique lines having linearity equivalent to that obtained when the size of the beam is reduced to half can be drawn.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a charged beam drawing device, and in particular to a charged beam drawing device that scans a minute circular charged beam over the entire surface of a sample and selectively draws a charged beam to obtain a desired pattern. The present invention relates to a beam drawing device.

[Conventional technology]

A conventional charged beam lithography apparatus will be explained using the configuration diagram of FIG. A charged beam 16 emitted from a charged beam generation source 1 is focused by a first lens 2 onto a circular hole in an aperture 3.9 A charged beam 16 that has passed through a hole in an aperture 3 is drawn by a blanking electrode 4. , or not to draw. When not drawing, a voltage is applied to the blanking electrode 4 to deflect the charged beam 16 so that the sample 8 is not irradiated with the charged beam 16.
When writing, no voltage is applied to the blanking electrode so that the charged beam 16 is not deflected.

The charged beam 16 that has passed through the blanking electrode 4 is
is focused onto the sample 8 by the lens 5 of. As shown in FIG. 11, the drawing order is such that the stage 9 moves continuously in the X direction,
The entire surface is scanned by deflecting the charged beam 16 in the Y direction by the deflector 6. In order to accurately IIJ# the movement of the stage 9, the position of the stage 9 is measured by a laser length measuring device 13, and the charged beam 16 is deflected by a deflector 7 for correction in the X direction. 14 is a drive circuit, and 15 is a control computer.

In the pattern memory 11, as shown in FIG. 12, for each point to be scanned, "1" for drawing or "0" for not drawing is stored.
, is stored. The information in the pattern memory 11 determines whether or not the blanking electrode 4 draws a charged beam. Since the capacity of the pattern memory in a normal drawing device is small, the semiconductor chip is divided in the Y direction and only the information for actually drawing is stored in the pattern memory 11.
to be memorized.

Next, a conventional diagonal line drawing method will be explained using FIG. 13. When drawing a trapezoidal pattern as shown in FIG. 13(a), diagonal lines were drawn in a stepwise manner as shown in FIG. 13(b). This is because, as described above, drawing is performed selectively based on the information of "1" or "0" stored in the pattern memory 11.

[Problems to be Solved by the Invention] The conventional charged beef 2 drawing device described above can only draw diagonal lines in a stepwise manner, and therefore has the disadvantage that the accuracy of the diagonal lines deteriorates. For example, the size of the charged beam is 0.5
In the case of μm, a maximum error of 0.35 μm will occur.

Furthermore, it is possible to reduce the errors that occur by reducing the size of the charged beam, but if the size of the charged beam is halved, the amount of data memory and The disadvantage is that the drawing time is quadrupled.

The present invention differs from the conventional charged beam drawing apparatus described above in that it has a function of preventing deterioration of diagonal line drawing accuracy.

[Means to solve the problem]

The charged beam lithography apparatus of the present invention scans a minute circular charged beam over the entire surface of a sample and selectively performs lithography to obtain a desired pattern.
A pattern memory having a capacity capable of storing peripheral information adjacent to a region including a desired pattern, and a determination circuit that determines whether or not the line is a diagonal line based on the information in the pattern memory and determines the irradiation time of the charged electric beam. and a control computer that controls the irradiation time of the charged electric beam based on the output of the determination circuit.

〔Example〕

FIG. 1 is a configuration diagram showing the main parts of Embodiment 1 of the present invention. In this embodiment, a pattern memory 11 has a capacity capable of storing information on the peripheral area adjacent to an area including a desired pattern.
, a diagonal line correction circuit 12 that determines whether or not a diagonal line is a diagonal line based on information in a pattern memory 11, and determines the irradiation time and position of the charged beam, and a control computer 15.

Determination as to whether or not it is a diagonal line (hereinafter referred to as diagonal line determination) is performed using the pattern data in the pattern memory 11 and (a) in FIG.
) to (d) by comparing with the reference patterns 21 to 24. If any of the reference patterns 21 to 24 matches the pattern data in the pattern memory 11, it is determined that the line is an oblique line, a control signal is sent to the blanking electrode 4, and the irradiation time of the charged beam irradiated onto the sample 8 is determined. control.

Furthermore, if only the part to be actually drawn is stored in the pattern memory 11 for comparison with the reference pattern, when drawing the end part of the pattern memory 11, the data around the point to be drawn will be Therefore, a pattern memory 11 that can store peripheral data is required. As shown in the block diagram of FIG. 3, the pattern memory 11 stores an area 30 within a large frame to be actually drawn, and areas 31 and 32 for providing surrounding information. This makes it possible to draw the edge portions of the information 302, 303, etc. in the pattern memory 11. :301,302.・・・・・・、40
1,402.・・・・・・ 501,502.・・・・・・
...,601,602. ......,701,702
．． ......,801,802. . . . indicates information in the pattern memory.

Next, assuming that 707 in FIG. 3 is to be scanned, the first
The diagonal line correction circuit 12 shown in the figure will be explained. When scanning 707, in this embodiment, the logic circuit shown in FIG. 4 is used for comparison with the reference pattern shown in FIGS. 2(a) to (d). That is, 607-“O”, 706="1" 707
="0", 708="O', 806-"1", 807="
"1", 808="0", that is, when it matches the reference pattern (a) in FIG. 2, B=1, and it is determined that it is a diagonal line. In Fig. 4, the process is performed only for the standard pattern (a), but the process is performed only for the standard pattern (b), (C
) and (d) are similarly determined.

In this way, when the diagonal line correction circuit 12 determines that the line is a diagonal line, it sends a signal to the control computer 15. The control computer 15 controls the blanking time of the blanking electrode 4 based on the sent signal. Moreover, as shown in the waveform diagrams of FIGS. 5(a) and (b),
The conventional control signal (Figure (a)) sent from the control computer 15 to the blanking electrode 4 is 52.53 at the time of drawing.
．． There were two types: 54 and 51.55.56 when not drawing. In this embodiment, the control signals sent from the control computer 15 to the blanking electrode 4 (FIG. (b)) are 62.63 when drawing, 64 when drawing is a diagonal line, and 61, 65 when not drawing. There are three types: .66. If it is determined that it is a diagonal line, 1/2 of the scanning time is drawn, and 1/2
The diagonal line is formed by reducing the density distribution of the charged beam irradiated onto the sample 8 so as not to draw the line. Further, when the reference patterns (C) and (d) in FIG. 2 are matched, the same effect can be obtained by drawing the second half without drawing the first half.

FIGS. 6(a) and 6(b) are examples of the reference pattern used in Example 2 of the present invention, and are diagrams showing a case where the diagonal line angle is approximately 30°. In the first embodiment, correction is performed only when the angle of the diagonal line is 45 degrees, whereas in the second embodiment, correction is possible even when the angle of the diagonal line is about 30 degrees.

Figures 6 (a) and (b) are diagrams showing a reference pattern with a diagonal line angle of about 30 degrees, and Figure (a) is a diagram for correcting a diagonal line with an angle of 30 degrees in a trapezoidal pattern as shown in Figure 7. This is a reference pattern for the purpose of the present invention, and corresponds to FIG. 2(a). In addition to the 45° angle correction circuit (FIG. 4) of the first embodiment, the diagonal line correction circuit 12 is similar to the circuit that judges whether the line matches the reference pattern 21 or not. A circuit is provided in parallel to determine the In addition, when scanning the part A of the reference pattern 32 as shown in FIG. 6(b), as shown in FIG.
As shown at 74 in a), irradiation is performed for only the first quarter of the total irradiation time. Similarly, when scanning the part B in FIG. 6(b), irradiation is performed for only the first 3/4 of the total irradiation time, as shown at 84 in FIG. 8(b).

In FIG. 6, an example is given only for the case of the diagonal line on the upper right which corresponds to the reference pattern 21 of Example 1, but the same procedure is given for the cases corresponding to other reference patterns 22, 23, and 24. . Also, in Figure 6, the angle of the diagonal line is approximately 30°.
Although only the case of 60° has been described, the case of about 60° can be easily realized by providing a circuit in parallel to determine whether or not the pattern matches the reference pattern of FIG. Furthermore, a diagonal line having an arbitrary angle can be realized by devising the logic circuit of the diagonal line correction circuit as shown in FIG.

〔Effect of the invention〕

As explained above, the present invention has the advantage that diagonal lines with high linearity can be drawn without reducing the size of the charged beam. If the size of the charged beam is halved, both the data memory capacity and drawing time will quadruple.In contrast, the present invention can produce diagonal lines with higher accuracy using the conventional data memory capacity and drawing time. can be drawn.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of Embodiment 1 of the present invention, and FIG. 2(a) to (
d) is a diagram showing the reference pattern used in Example 1, FIG. 3 is a configuration diagram of a pattern memory capable of storing an area adjacent to the drawing area in Example 1, and FIG. 4 is a diagram showing the diagonal line in Example 1. Logic circuit diagram of the correction circuit, FIG. 5(a),(b)
) is a waveform diagram showing the blanking time control signal comparing the conventional one and the first embodiment, FIGS. 6(a) and (b) are diagrams showing the reference pattern used in the second embodiment of the present invention, and FIG. 8(a) and 8(b) are waveform diagrams showing the blanking time control signal of the second embodiment,
FIG. 9 is a diagram showing the reference pattern used in Example 2,
Figure 0 is a configuration diagram showing a conventional charged beam lithography system.
The figure shows the conventional drawing order, Fig. 12 shows the conventional pattern memory, Figs. 13 (a) and (b) are explanatory diagrams of the conventional diagonal line drawing method, and Fig. 14 shows the conventional beam drawing method. FIG. 4 is an explanatory diagram of a drawing method when the size is reduced. DESCRIPTION OF SYMBOLS 1... Charged beam source, 2... First lens, 3...
・Aperture, 4...Blanking electrode, 5...
Second lens, 6, 7... Deflector, 8... Sample, 9
...Stage, 10...Data memory, 11...
Pattern memory, 12... Diagonal line correction circuit, 13...
- Laser length measuring device, 14... Drive circuit, 15... Control computer, 16... Charged beam, 21-24.
...Reference pattern, 30...Region to be actually drawn, 3
1.32...Area providing surrounding information, 41-43
...chip.

Claims (1)

[Claims] In a charged beam drawing device that scans a minute circular charged beam over the entire surface of a sample and selectively draws a desired pattern, the device has a capacity that can store information about areas adjacent to the area containing the desired pattern. A determination circuit that determines whether or not the line is an oblique line based on the information in the pattern memory and determines the irradiation time of the charged beam, and controls the irradiation time of the charged beam based on the output of this determination circuit. A charged beam lithography apparatus comprising a control computer.