JPH02295106A - Electron beam aligner - Google Patents

Abstract

PURPOSE:To facilitate detection of alignment position errors caused by the change of a relative position between a mirror cylinder and a laser measure by a method wherein a means for measuring a displacement caused by the vibration of the mirror cylinder is provided. CONSTITUTION:An electron beam 2 generated by an electron gun 1 reaches a sample 5 to expose a required pattern while it is subjected to deflection control by a positioning deflector 4 which is provided in the lower part of a mirror cylinder 3. The position coordinate error of a movable stage 7 measured by a laser measure 6 and the height error of the sample 5 measured by a height measure 8 are fed back to the positioning deflector 4 to correct the position errors of the electron beam. A laser beam 9 which is emitted by the laser measure 6 and used for measuring the stage position is divided by a beam splitter 10 and reaches a mirror 11 provided on the ceiling of a sample chamber 12. With this mechanism, the displacement of the ceiling of the sample chamber 12 can be measured by the laser measure 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electron beam exposure apparatus used in the manufacturing process of semiconductor integrated circuits.

[Conventional technology]

As shown in FIG. 3, a conventional electron beam exposure apparatus consists of a lens barrel 3 containing an electron optical system, and a sample chamber 12 connected to the lower part of the lens barrel 3 in which a sample 5 is placed.

An electron beam 2 emitted from an electron gun 1 in a lens barrel 3 passes through a lens barrel 3 containing an electron optical system including an extraction electrode, a positioning deflector 4, and the like, and is irradiated onto a sample 5. At this time, the irradiation position of the electron beam 2 on the sample surface is controlled by a positioning deflector 4, so that a desired integrated circuit pattern or the like is exposed.

The sample 5 is placed on a movable stage 7, and is moved in the X-axis and Y-axis directions by driving a servo motor 14. The position of the movable stage 7 is measured by a laser length measuring device 6 with a resolution of about 0.01 μm. Since the sample 5 is fixed at a fixed position on the movable stage 7, this is equivalent to the sample position being measured.

The displacement of the sample 5 in the Z-axis direction is measured by a height measuring device 8. These positional and height displacements with respect to the sample 5 affect the positional accuracy of electron beam exposure and are fed back to the positioning deflector 4.

[Problem to be solved by the invention]

The conventional electron beam exposure apparatus described above focuses only on the position of the sample 5 in the x, y, and z axis directions, assuming that the relative positions of the lens barrel 3 containing the electron optical system and the laser length measuring device 6 remain unchanged. Deflection control and deflection correction are performed.

However, in the above-mentioned electron beam exposure apparatus, the lens barrel 3 may also vibrate due to external vibrations or vibrations generated by the apparatus itself, and may fall down by 3 to 5 μrad as shown in FIG.

Namely. The electron beam 2 generated from the electron gun 1 due to the collapse of the lens barrel 3 is irradiated onto the sample 5 with a positional error of Δd. Conventional electron beam exposure apparatuses do not have means for correcting or detecting this type of positional error, which causes a decrease in reliability and yield of semiconductor integrated circuits.

Further, if an attempt is made to discover such exposure errors by actually measuring the pattern on the sample after exposure is completed, a large amount of man-hours and a highly accurate inspection device are required.

In contrast to the conventional electron beam exposure apparatus described above, the electron beam exposure apparatus of the present invention is equipped with a means for measuring the vibration, or displacement, of the lens barrel, and measures the exposure position caused by changes in the relative positions of the lens barrel and the laser length measuring device. The difference is that errors can be detected.

[Means to solve the problem]

The electron beam exposure apparatus of the present invention includes a lens barrel containing an electron optical system and a sample chamber connected to the lower part of the lens barrel,
An electron beam exposure apparatus for drawing a pattern on a sample placed in the sample chamber using a deflection-controlled electron beam is provided with means for measuring displacement due to vibration of the mirror strip.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view of a first embodiment of the invention.

The electron beam exposure apparatus includes a lens barrel 3 containing an electron optical system, a sample chamber 12 connected to the lower part of the lens barrel 3 in which a sample 5 is placed, and a laser length measuring device 6 provided within the sample chamber 12.
, splitter 10, and mirror 11 installed on the ceiling of the sample chamber.
and a means for measuring vibration of the lens barrel.

An electron beam 2 emitted from an electron gun 1 reaches a sample 5 while being deflected and controlled by a positioning deflector 4 located at the bottom of a lens barrel 3, and exposes a desired pattern. The position coordinate error of the movable stage 7 measured by the laser length measuring device 6,
The height error of the sample determined by the height measuring device 8 is fed back to the positioning deflector 4, and is used for correcting the position error of the electron beam.

A laser beam 9 from a laser length measuring device 6 used to measure the stage position is split by a splitter 10 and reaches a mirror 11 on the ceiling of the sample chamber.

With this mechanism, the displacement of the ceiling of the sample chamber can be measured by the laser length measuring device 6.

That is, as shown in FIG. 4, when the lens barrel 3 is in the collapsed state, the sample chamber ceiling 12A on which the lens barrel 3 is placed is
The deflection varies by 0.3 to 0.6 μm. If we calculate the displacement of the ceiling from this, we can see that the lens barrel 3 causes exposure errors in the pattern.
Fluctuations in the relative position of the laser length measurement system are immediately detected.

Therefore, by providing a means such as displaying a warning light when this fluctuation value exceeds a certain value, the work can be stopped, which reduces errors in drawing patterns and improves the yield of semiconductor integrated circuits. be able to.

FIG. 2 is a sectional view of a second embodiment of the invention.

In the second embodiment, a plurality of piezoelectric elements 20 are sandwiched between the lens barrel 3 and the sample chamber ceiling 12A, so that displacement due to vibration of the lens barrel 3 can be detected. Therefore, piezoelectric element 2
By observing the change in the output voltage of zero, the vibration and displacement of the column can be easily measured.

〔Effect of the invention〕

As explained above, by providing a means for measuring the displacement due to vibration of the lens barrel, the present invention can quickly eliminate pattern exposure errors of 0.2 to 0.3 μm, which were previously overlooked, during exposure work. There are effects that can be discovered. Therefore, the reliability and yield of semiconductor devices are improved.

Attempting to detect pattern exposure errors caused by vibration of the lens barrel by actually measuring the pattern on the sample after exposure has been completed requires a large amount of time and high-precision inspection equipment, but according to the present invention, these resources can be reduced. can also be omitted.

[Brief explanation of drawings]

1 and 2 are sectional views of the first and second embodiments of the present invention, FIG. 3 is a sectional view of a conventional electron beam exposure apparatus, and FIG. 4 is an electron beam with the lens barrel in a collapsed state. It is a sectional view of an exposure device. 1... Electron gun, 2... Electron beam, 3... Lens barrel,
4... Positioning deflector, 5... Sample, 6... Laser length measuring device, 7... Movable stage, 8... Height measuring device, 9... Laser beam, 10... Suburitsuta, 11
...Mirror 12...Sample chamber, 12A...Sample chamber ceiling, 14...Servo motor, 20...Piezoelectric element.

Claims (1)

[Claims] An electron beam exposure device that consists of a lens barrel containing an electron optical system and a sample chamber connected to the bottom of the lens barrel, and that draws a pattern on a sample placed in the sample chamber using a deflection-controlled electron beam. An electron beam exposure apparatus characterized in that the electron beam exposure apparatus is provided with means for measuring displacement due to vibration of the lens barrel.