JPS6297241A - X-ray generator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of the Invention] The present invention relates to an X-ray generation device that generates X-rays from a target by colliding an electron beam emitted from an electron gun with the target. The present invention relates to an X-ray generator that can adjust the generation position and direction of X-rays and can generate high-output X-rays.

[Prior Art] In recent years, in the manufacture of semiconductor devices such as LSIs, X-ray exposure using soft X-rays with wavelengths of X-rays ranging from several to several dozen has been performed. When using soft X-rays as the exposure beam for this X-ray exposure, if a straight electron gun is used, the electron gun's cathode material (tungsten or tantalum) will adhere to the target surface and absorb the soft X-rays. There is a drawback.

Therefore, in order to eliminate this drawback, a deflection type electron gun is used, which has a structure in which the electron beam is deflected so that the cathode material does not adhere to the target.

FIG. 2 shows a configuration diagram of a conventionally used deflection type electron gun. In the figure, 1 is a cathode, 2 is an electron beam, 3 is an electrostatic deflection plate, 4 is a target, 5 is a generated X-ray, 10
indicates cooling water for cooling the target. An electron beam 2 emitted from a cathode 1 is deflected by an electrostatic deflection plate 3 and irradiated onto a target 4, whereby X-rays 5 are emitted. In the conventionally used deflection type electron gun having such a configuration, the electrode arrangement of the electron gun is determined in advance, so that the trajectory of the electron beam 2 is always constant. Therefore, the electron beam 2 at target 4
The disadvantage is that the irradiation position of the X-ray cannot be adjusted, and the X-ray generation position and the X-ray direction cannot be adjusted.

Further, an electron gun used for X-ray exposure is required to have a high output in order to improve the throughput of the exposed object. However, in the case of an electron gun as shown in Fig. 2, the distance between the cathode 1 and the target 4 is relatively long;
The electric field strength near becomes low. Therefore, when the electron beam is generated, a space charge effect occurs and the current of the electron beam 2 is saturated, resulting in a drawback that a large output cannot be obtained. In particular, in the case of soft X-rays with long wavelengths, the accelerating voltage of the electron beam is generally low, so this space charge effect is significant, and high output of the electron beam cannot be expected.

[Objective of the Invention 1] In view of the problems of the conventional type described above, the present invention is capable of generating a high-output electron beam, and furthermore, by changing the irradiation position of the electron beam on the target, the X-ray generation position and X
An object of the present invention is to provide an electron gun for generating X-rays whose direction of rays can be easily adjusted.

[Explanation of Examples] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration diagram of an X-ray generator according to an embodiment of the present invention. Components that are common or correspond to the conventional type shown in FIG. 2 are designated by the same numbers.

In the figure, 6 is a Wehnelt electrode, 7 is a nine-voltage power supply,
8 is a voltage divider, and 11 is an extraction electrode. 9 indicates an equipotential surface. The electron beam 2 emitted from the cathode 1 is extracted by an extraction electrode 10 arranged in front of the cathode. This extraction electrode 1
0 is applied with a positive potential voltage obtained by dividing the high voltage generated by the high voltage power supply 7 with the voltage divider 8. This applied voltage is variable in order to adjust the target irradiation position of the electron beam, which will be described later.

The equipotential distribution 9 is determined by the shape and position of each of the extraction electrode 10, the deflection electrode 3, and the target 4, and the voltage applied to each electrode. The trajectory of the electron beam 2 that has passed through the aforementioned extraction electrode 10 is determined by this equipotential distribution 9, and is irradiated onto the target 4. That is, the equipotential distribution 9 acts as a deflection/focusing lens on the electron beam 2.

In the X-ray generator according to this embodiment, the extraction electrode 1
0 is asymmetrically constructed and also serves as an electron beam deflection electrode. Therefore, by changing the voltage applied to the variable extraction electrode 10, the equipotential distribution 9 can be changed. According to this change in the equipotential distribution 9, the trajectory of the electron beam 2 changes, making it possible to adjust the position of the electron beam irradiated onto the target 4. Therefore, the X-ray generation position can be easily adjusted. Also, as mentioned above,
The extraction electrode also serves as a part of the deflection electrode, which has the advantage of simplifying the structure of the device.

Furthermore, since this extraction electrode is provided near the front surface of the cathode 1, the electric field strength on the front surface of the cathode can be increased by applying a voltage, and the above-mentioned space charge effect can be weakened. As a result, saturation of the current of the electron beam 2 is eliminated, and a high-output electron beam can be irradiated, making it possible to increase the output of X-rays.

[Effects of the Invention] As explained above, according to the present invention, an electron beam extraction electrode that is asymmetric with respect to the electron emission axis of the electron gun that deflects the electron beam is provided near the front surface of the cathode of the electron gun, so that high output can be achieved. It is possible to irradiate a target with an electron beam of 1000 yen, and it is possible to increase the output of X-rays. In addition, since the voltage applied to the extraction electrode is variable, the electron beam can be irradiated to the desired position on the target by adjusting the voltage, making it easy to adjust the X-ray generation position and the direction of the X-ray. There is an effect that it can be done.

[Brief Description of the Drawings] Fig. 1 is a configuration diagram of an X-ray generating electron gun according to an embodiment of the present invention, and Fig. 2 is a configuration diagram of a conventionally used deflection type electron gun. . 1: Cathode, 2: Electron beam, 3: Deflection electrode, , 4: Target, 5: X-ray, 6: Wehnelt electrode, 7: High voltage power supply, 8: Voltage divider, 9: Equipotential distribution, 10: Cooling water , 11:
Extraction electrode.

Claims (1)

[Claims] 1. An electron gun for generating an electron beam, and an X-ray gun that is irradiated with the electron beam.
An X-ray generator having a target that generates a beam, the X-ray generator comprising an electron beam extraction electrode that is asymmetrical with respect to the electron emission axis of the electron gun and deflects the electron beam near the front surface of the cathode of the electron gun. Generator. 2. The X-ray generator according to claim 1, wherein the voltage applied to the electrodes is variable.