JPS62219442A - Linear electron beam generator - Google Patents

Abstract

PURPOSE:To make it possible to stably form linear electron beams having uniform intensity distribution over a range of several mm in length by arranging plural cathodes and imparting thereon fine adjusting bias voltages independently variable, respectively. CONSTITUTION:An electron gun 1 is composed of plural cathodes 2 and Wehnelt 3 with openings for surrounding said cathodes 2 while fine adjusting bias power supplies 11 independently variable are connected to said cathodes 2, respectively. And, each electron beam is accelerated and converged by an acceleration electrode so that a sample 7 is subjected to scanning through an electronic optical lens 5 and deflection coil 6. Therefore, a long sized linear electron beam can be formed since the electrons from plural cathodes 2 are converged by use of an electronic optical system having a fairly large aperture. Further, linear electron beams having uniform intensity distribution over a range of 6 to 7mm in length can be obtained by adjusting bias voltages of respective cathodes.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a linear electron beam generator, and in particular to an S OI
The present invention relates to a linear electron beam generator used for annealing semiconductor films such as IBI or welding and processing mechanical parts.

[Conventional technology]

When an electron beam is used to anneal a semiconductor film or to weld or process mechanical parts, the use of a linear electron beam is more advantageous than a point-shaped electron beam because the process can be completed in a shorter time. Conventional techniques for obtaining this type of linear electron beam include a method using a linear cathode or a method using a point cathode to scan a point beam in one direction at high speed to obtain a linear heating area. It is used.

(Madashi Nishimura, Hiroshi Akasaka-1 Applied Physics, Voe, 54 (19
85>, p. 1274) [Problems to be Solved by the Invention] In the above-mentioned conventional technology for obtaining a linear electron beam, when a linear cathode is used, the beam length is about 3 to 5 yen. Although it is possible to obtain a relatively uniform beam intensity distribution up to that length, it is difficult to obtain a uniform beam having a longer length. Furthermore, the method of scanning a dot beam at high speed using a dot cathode has the disadvantage that it is difficult to obtain a large beam current and is not suitable for large area processing.

SUMMARY OF THE INVENTION An object of the present invention is to solve these conventional problems and provide a linear electron beam generator that can stably generate a linear electron beam having a length of several mo+.

Means for Solving Problems] The linear electron beam generating device of the present invention includes a Wehnelt electron gun having a plurality of cathodes and an opening that surrounds the plurality of cathodes, and the electron gun. The bias voltage supplied to the acceleration electrode, the electron optical lens means, the beam deflection means, and the plurality of cathodes, each of which accelerates and converges the electron beam without aberration and scans the sample surface, is independently variable. Equipped with a bias power supply that can be used.

[Effect]

Experiments have confirmed that it is possible to project cathode images onto the sample surface by accelerating electrons extracted from multiple cathodes and focusing them using a relatively large-diameter electron optical system to reduce aberrations.

Therefore, by using a plurality of cathodes with a length that provides a uniform beam intensity distribution, it is possible to obtain a longer linear electron beam. In addition, by making it possible to vary the bias voltages for multiple cathodes independently, the beam intensity obtained from each cathode can be varied, and a uniform intensity distribution can be obtained over the entire length of the linear beam. be able to.

〔Example〕

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

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an electron gun used in this embodiment, and FIG. 3 is a graph showing a beam intensity distribution obtained by this embodiment.

This embodiment includes an electron gun 1, a cathode 2 and Wehnelt 3 that constitute the electron gun 1, an accelerating electrode 4, a lens coil 5, a deflection coil 6, a sample 7, a sample stage 8, an accelerating electrode 9, a main bias power supply 10, and a fine adjustment It has a bias power supply 11.

The electron gun 1 has three cathodes 2 and Wehnelts 3. The cathodes 2 are directly heated tungsten filaments, and three cathodes are used. The length of the filament is 3 am' for the central cathode 2a, 2III11 for the cathodes 2b and 2C at both ends, and the spacing between them is IIIm. Wehnelt 3 is shaped to surround each cathode 2a, 2b, 2c. A constant voltage of 15 kilovolts is applied to the accelerating electrode 4 from an accelerating power source 9 to accelerate the electron beam.

The lens coil 5 focuses the electron beam, and the deflection coil 6 scans the sample 7 on the sample stage 8 with the electron beam. The main bias power supply 10 is a stabilized power supply that can be continuously varied from O to 1000 volts.
By changing the zero voltage, the beam current reaching the sample is set to a desired current value. Bias power supply 11 for fine adjustment
is a power source used to obtain a uniform beam intensity distribution, and is a stabilized power source that can be continuously varied from 0 to 50 volts.

- According to this embodiment of the configuration and operation as described in h.
10 to 100 linear electron beams with a length of ~7 mm
Stable beam current can be obtained in the milliampere beam current range. Furthermore, as a result of measuring the beam intensity distribution using a Faraday cage, the intensity change within a beam length of 6 am can be within ±5% over a current range of 10 to 100 milliamperes.

This is because, as shown in FIG. 3, the beam intensity distribution 12 obtained from each cathode is as shown in the figure, and as a result, a uniform combined beam intensity distribution 13 is obtained.

〔Effect of the invention〕

As explained above, the present invention provides a bias power supply for fine adjustment which has a plurality of cathodes, a Wehnelt electrode, an accelerating electrode, an electron optical lens system, and a beam deflection system, and in which the bias voltages for the plurality of cathodes can be varied independently. By providing this, it is possible to stably obtain a linear electron beam with a uniform intensity distribution over a length of 6 to 7 inches in a beam current range of 10 to 100 milliamperes, and therefore, a uniform film quality can be achieved with a short annealing time. It is possible to obtain a semiconductor film having the following characteristics, and there is also an effect that mechanical parts can be welded and processed in a short time.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an electron gun used in this embodiment, and FIG. 3 is a diagram of an electron gun according to this embodiment.
2 is a graph showing a beam intensity distribution obtained by DESCRIPTION OF SYMBOLS 1... Electron gun, 2... Cathode, 3... Wehnelt, 4... Accelerating electrode, 5... Lens coil, 6...
・Clean white coil, 7...sample, 8...sample stand, 9...
- Accelerating electrode, 10... Main bias power supply, 11... Bias power supply for fine adjustment, 12... Beam intensity distribution obtained from each cathode, 13... Combined beam intensity distribution. G;1:) I 13

Claims (1)

[Claims] An electron gun consisting of a Wehnelt electron gun having a plurality of cathodes and an opening that surrounds the plurality of cathodes, and an acceleration for accelerating the electron beams from the electron gun, converging them without aberration, and scanning them over a sample surface. A linear electron beam generating device comprising an electrode, an electron optical lens means, a beam deflection means, and a bias power source whose bias voltage supplied to the plurality of cathodes can be varied independently.