JPS5824010B2 - Method for aligning aperture plates with rectangular electron beam passing apertures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for applying a shaped electron beam using first and second aperture plates each having a rectangular electron beam passage aperture and an electron beam deflecting means provided between the aperture plates. The present invention relates to a method for aligning an aperture plate used in an electron beam exposure apparatus that projects an image onto an exposure material.

FIG. 1 shows an example of an electron beam exposure apparatus in which the present invention is implemented, and 1 is an electron gun.

An electron beam generated from the electron gun 1 is projected by a converging lens 2 onto a first aperture plate 4 having a rectangular aperture 3.

The electron beam passing through the aperture 3 is appropriately deflected by an electrostatic deflector 5 and projected onto a second aperture plate 7 having a rectangular aperture 6 by an electron lens 4L.

As a result, the cross-sectional shape of the electron beam passing through the second aperture 6 becomes variable depending on the amount of deflection of the electron beam by the deflector 5.
The electron beam that has passed through the aperture 6 is irradiated onto a material to be exposed 9 by a projection lens 8 .

The electron beam irradiation position on the material 9 is changed by a deflector 10, so that a desired shape is exposed on the material 9.

Now, in the apparatus having the above-mentioned structure, for example, a second
When exposing an elongated rectangular shape as shown in figure a,
The first and second aperture plates 4 and 7 and the deflector 5 form a rectangular electron beam S1 shown in FIG. Scanning and electron beam S2. S3゜...Sn is projected onto the material to expose the pattern.

In this case, if one side of the rectangular electron beam 51 (S2 . is exposed.

However, when the parallelism between the sides of the rectangular cross section and the scanning direction of the electron beam is poor, such as the electron beam R1 shown in FIG. Even if the electron beams are projected onto a material, it is not possible to accurately join the unit exposed figures by each electron beam, and the figures cannot be exposed with high precision.

In view of the above points, each side of the first and second rectangular electron beam passing openings 3 and 6 is made parallel to the electron beam scanning direction (X direction and Y direction) before starting exposure of the material. The first and second aperture plates must be aligned so that the first and second aperture plates are aligned.

Conventionally, this alignment is performed by arranging a Faraday cage 11 shown in FIG. This is done by scanning an electron beam EB with a rectangular cross section.

The intensity of the signal obtained from the cage 11 by scanning the electron beam decreases as the electron beam EB is shielded by the wire 12, and the signal shown in FIG. 4a is obtained.

The signal shown by the solid line in FIG. 3 is due to the electron beam EB shown by the solid line in FIG. This is due to the electron beam EB' shown by the broken line in FIG. 3, which has poor parallelism with the electron beam EB', and the signal intensity due to the electron beam EB' gradually decreases.

By differentiating the signal shown in FIG. 4A, the signal shown in FIG. 4S is obtained, and by further differentiation, the signal shown in FIG. 4C is obtained.

The height of the peak of the signal in FIG. 4C increases as the parallelism between the side of the electron beam and the wire end W improves.

From this, if the aperture plates 4 and 7 of the apparatus shown in FIG. 1 are rotated so that the height of the peak is maximized, each side of the electron beam will be parallel to the scanning direction (X or Y direction). It can be adjusted as desired.

Here, FIG. 5 shows the relationship between the first aperture 3, the second aperture 6, and the electron beam EB projected onto the material.
The shape and size of the electron beam EB can be changed depending on the degree of overlapping of the apertures 3 and 6.

Now, when the aperture plate 4 is rotated, if the rotation center of the aperture plate 4 coincides with the center G (optical axis) of the aperture 3, the height of the peak signal in FIG. It changes approximately depending only on the parallelism between the side and the one end W of the wire.

However, the center of rotation of the aperture plate 4 is usually different from the center of the aperture 3. For example, if the center of rotation of the aperture plate 4 is C, then by rotating the aperture plate 4 several times, the aperture 3 will be as shown by the broken line in FIG. Therefore, the shape and size of the electron beam shaped by the apertures 3 and 4 change greatly.

As a result, the height of the peak in FIG. It will be difficult to align them.

The present invention has been made in view of the above-mentioned points, and provides a method that can accurately align aperture plates even when the rotation center of each aperture plate does not coincide with the center of the opening. .

In one embodiment of the present invention, the length of each side of the electron beam passing aperture 6 provided in the second aperture plate 7 is twice the length of each side of the aperture 3 provided in the first aperture plate 4. is made to the size of

First, when aligning the first aperture plates 4, a signal is supplied to the deflector 5 so that all of the electron beams that have passed through the first aperture 3 pass through the second aperture 6, as shown in FIG. The electron beam passing through the aperture 6 is connected to the wire 1 shown in FIG.
is scanned by the deflector 10 in a direction perpendicular to the straight end W of 2.

If the aperture plate 4 (aperture 3) is rotated here, even if the rotation center of the aperture plate 4 and the center (optical axis) of the aperture 3 do not coincide, the electron beam passing through the first aperture 3 Since all the electron beams pass through the second aperture, there is no change in the shape or size of the electron beam. Therefore, the height of the signal peak shown in FIG. 4C is parallel to the side of the first aperture and the end W. Therefore, if the aperture plate 4 is rotated so that the height of the peak becomes the highest, each side of the first aperture 3 will be aligned parallel to the scanning direction of the electron beam. Become.

After the above-described alignment of the first aperture plates is completed, a signal is supplied to the deflector 5, and as shown in FIG. 7, a part of the electron beam passing through the first aperture 3 is blocked by the second aperture plate. , only one side of the rectangular cross section of the electron beam passing through the opening is shaped by one side of the second opening 6, which should be parallel to the linear end W of the wire 12.

(The other three sides are shaped by the first opening.

) When the second aperture plate 7 is rotated in this state, even if the rotation center of the second aperture plate 7 and the center (optical axis) of the second aperture do not coincide, the second aperture plate 7 is rotated. The size of the cross-sectional shape of the electron beam passing through the aperture 6 hardly changes, and the height of the peak of the signal shown in FIG. 1
If the second aperture plate is rotated so that the height of the peak becomes the highest depending on the parallelism with the end W of the second aperture plate,
Each side of the second aperture 6 is aligned parallel to the scanning direction of the electron beam.

After the alignment of the first and second aperture plates is completed, if the exposure of the material to be exposed is started, the unit exposure figures can be precisely joined, greatly improving exposure accuracy. can be done.

Although the present invention has been described in detail above, the present invention is not limited to the embodiments described above and can be modified in many ways.

For example, the second aperture plate may be aligned first, and then the first aperture plate may be aligned.

Furthermore, although a Faraday cage is provided at the bottom of the wire to detect the electron beam, it is also possible to detect secondary electrons from a portion of the wire, or even to detect two types of electron beams with different secondary electron emission abilities. A linear boundary may be formed by a substance, and secondary electrons from the substance may be detected.

Furthermore, the second opening was configured to be larger than the first opening,
For example, the first aperture and the second aperture may have the same size, in which case an electron lens provided between the first aperture plate and the second aperture plate can reduce the electrons generated by the first aperture. The line image may be reduced and projected onto the second aperture plate.

Furthermore, in the embodiment described above, the aperture plate is rotated so that the height of the peak signal shown in FIG. 4C becomes the highest.
After aligning the aperture plates, for example, from the signal shown in FIG. 4C, a signal corresponding to the width of the electron beam with a rectangular cross section was obtained,
A similar effect can be obtained by rotating the aperture plate so that the signal corresponding to the width is minimized.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of an electron beam exposure apparatus for carrying out the present invention, Fig. 2 is a diagram for explaining an exposure method using the apparatus of Fig. 1, and Fig. 3 is a diagram showing a stage of a material to be exposed. FIG. 4 shows a Faraday cage and a conductive wire arranged in
FIG. 5 is a diagram showing the output signal of the Faraday cage shown in FIG. 3 and a differential signal of the signal; FIG. 5 is a diagram showing the relationship between the first and second electron beam passing apertures and the shaped electron beam; FIGS. 6 and 7 are diagrams showing the relationship between the first and second electron beam passing apertures in the present invention. 1... Electron gun, 2. L, 8...Electron lens, 3°6...Electron beam passing aperture, 4,7...
...Aperture plate, 5.10... Electrostatic deflector, 9... Material to be exposed.

Claims (1)

[Claims] 1. All of the electron beams that have passed through the first rectangular opening of the first aperture plate are passed through the second rectangular opening of the second aperture plate, and the electron beam that has passed through the second rectangular opening is Scanning a member having a linear boundary in a direction substantially perpendicular to the boundary, detecting an electron beam influenced by the boundary, and adjusting the first aperture plate based on the detected signal. The electron beam is rotated to align one side of the first rectangular opening substantially parallel to the linear boundary, and passes through the first rectangular opening after or before alignment of the first aperture plate. A side of the rectangular cross-section of the electron beam that has passed through the opening by the side of the second rectangular opening that is to be aligned parallel to the linear boundary of the member, with a part of the opening being blocked by the second aperture plate. The electron beam passing through the second rectangular opening is scanned over the member having the linear boundary in a direction substantially perpendicular to the boundary, and the electron beam influenced by the boundary is scanned. and rotating the second aperture plate based on the detected signal so that one side of the second rectangular opening and the linear boundary are aligned substantially parallel to each other. The alignment force of the aperture plate with