JPS6388794A - Plasma x-ray source - Google Patents

Abstract

PURPOSE:To reduce a stain of an X-ray pickup window, by connecting a ceramic capacitor to the circuit side of a capacitor bank. CONSTITUTION:A ceramic capacitor 20 receives a stress in the direction to contract the space between poles of the capacitor 20 in the charged condition. When a discharge occurs between electrodes 11 and 12, the stress the ceramic capacitor 20 is receiving is released in a very short time, and the ceramic capacitor 20 is restored to the original condition, when, the ceramic capacitor 20 generates supersonic waves 21. The supersonic waves 21 pass through a circuit 7, reach to a discharge unit 5, and arrive at an X-ray pickup window 15. On the other hand, the evaporated substance from the electrodes 11 and 12 is at the loosely attached condition at a high temperature without losing the temperature at this time. Therefore, such an attached substance at the X-ray pickup window 15 is removed easily by the supersonic oscillation, and the stain there is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an xvA source for an X-ray lithography apparatus for LSI manufacturing, and more particularly to a plasma X M source that reduces contamination of an X-ray extraction window.

[Conventional technology]

As a conventional device, the one shown in Japanese Unexamined Patent Publication No. 151945/1988 is known. As shown in FIG. 6, this is the charging power source 1. Charging resistor 2, capacitor 3. Discharge switch 4. Electrical line 7. It is composed of a discharge device 5. 16 is an exposure mask, 17 is an exposure wafer,
19 is an aligner.

The discharge device 5 includes an exhaust device and a vacuum vessel 18 (not shown).
．． Den I'! ! It consists of 11.12. The operation is
First, power is supplied to the capacitor 3 from an appropriately controlled charging power source 1 via a charging resistor 2, and the capacitor 3 is charged to a predetermined voltage. Thereafter, the discharge switch 4 is closed by an external factor (not shown), and the voltage is applied between the pair of electrodes 11 and 12 of the discharge device 5 to cause a discharge, and plasma is generated. By supplying the energy generated and then stored in the capacitor, a plasma pinch is created and intense X-rays 14 are emitted. The protective resistor 6 is a discharge bag VT5, which is provided to absorb the energy of the capacitor 3 when no discharge occurs. This 1% 14 is irradiated onto the resist-coated wafer 17 through the X-ray extraction window 15 and the X-ray mask 16, thereby exposing it. Such conventional devices are still in the research stage, and oil-immersed paper capacitors and oil-immersed plastic film capacitors, which are generally used for electric power, are used as power supply capacitors.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into consideration measures against the X-ray extraction window being contaminated by evaporated substances from the electrodes.

That is, when a discharge occurs between the electrodes 11 and 12,
A plasma pinch occurs, producing high-energy ions and electrons. Further, the electrode material melts and metal vapor is released from the electrode.

These high-energy ions and electrons are transferred by magnetic means to xI! It is possible to prevent it from flying into the takeout window, but since metal vapor is neutral, the trajectory cannot be bent.
It was difficult to find a way to prevent damage to the wire outlet window.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to
To provide a plasma X-ray source with reduced contamination of the radiation extraction window A ceramic capacitor is installed in the section.

[Effect]

That is, a ceramic capacitor is a type of piezoelectric element, and when it is charged in advance and then rapidly discharged, the strain disappears rapidly, and in the process it generates ultrasonic vibrations. This ultrasonic vibration is transmitted to the discharge device through constituent objects such as electrical circuits, and further to the XI! Spreads to the extraction window. As a result, the metal vapor atoms that were loosely attached to the X-ray extraction window are released into space again, reducing the amount of contamination of the X-ray extraction window.

〔Example〕

Hereinafter, the present invention will be explained in detail using the embodiment shown in FIG. 1, and the same components as those in the embodiment shown in FIG. 6 are given the same numbers. A ceramic capacitor 20 is provided between the capacitor 3 and the electric circuit 7. In a charged state, the ceramic capacitor 20 is subjected to stress in a direction that reduces the distance between the electrodes of the ceramic capacitor 2o. When a discharge occurs between the electrodes 1i and 12 of the discharge device [5], the stress that the ceramic capacitor 20 has been under is released in a very short time. the result.

The ceramic capacitor 20 is restored to its original state.

The ceramic capacitor at this time will generate ultrasonic waves 21. This ultrasonic wave passes through the electric path 7 and reaches the discharge device 5, and then reaches the X-ray extraction window]5.

On the other hand, at this point, the evaporated substances from electrodes 11 and 12 are
It remains hot and loosely attached. As a result, substances adhering to the X-ray extraction window are easily removed by ultrasonic vibration, resulting in a reduction in contamination.

FIG. 2 shows another embodiment of the present invention, which is an example applied to a circuit provided with a discharge switch 4, and this can also achieve exactly the same effect as in FIG. '5S1.

FIG. 3 shows yet another embodiment of the present invention, in which all the power supply capacitors are ceramic capacitors, and this can also achieve exactly the same effect as in FIG. 1.

FIG. 4 shows yet another embodiment of the present invention. This is an example in which a cable 22 is used instead of the conductor plates 8 and 9 for the electric circuit, and this can also achieve exactly the same effect as the embodiment shown in FIG. FIG. 5 shows yet another embodiment of the invention.

This is an example in which ceramic capacitors are arranged in a side inch shape between the conductor plates 8 and 9 of the electric circuit. In this example, in addition to the same effects as the embodiment shown in FIG. 1, the inductance of the capacitor circuit can be made very small, the rise of the discharge current becomes faster, and X-rays that are stronger can be generated accordingly.

In addition, in the examples shown in Figures 3 to 5, all capacitors are ceramic capacitors, which has the additional effect of extending the life of the number of charge/discharge cycles by about two orders of magnitude compared to capacitors using conventional oil-immersed films. can also be played.

〔Effect of the invention〕

As explained above, in summary, the present invention provides a plasma Since the ceramic capacitor is disposed on the electric circuit side of the bank, substances adhering to the X-ray extraction window are easily removed by ultrasonic vibration, resulting in a reduction in contamination of the xi extraction window.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the present invention, FIG. 2 shows another embodiment of the invention, FIG. 3 shows another embodiment of the invention, FIG. 4 shows yet another embodiment of the invention, and FIG. The figure shows yet another embodiment of the invention,
FIG. 6 shows a conventional example. 5...Discharge device + 11.12...Electrode, 18...
- Vacuum container, 7... Electric circuit, 3... Capacitor bank, 20... Ceramic capacitor.

Claims (1)

[Claims] 1. In a plasma X-ray source consisting of a discharge device provided in a vacuum container and having at least one pair of electrodes, an electric circuit for supplying a pulsed large current to the discharge device, and a capacitor bank, at least the electric circuit side of the capacitor bank A plasma X-ray source characterized by having a configuration in which a ceramic capacitor is arranged and connected to the.