JPH01243349A - Plasma extreme ultraviolet light generator - Google Patents

Abstract

PURPOSE:To reduce the rising time of a discharge, improve various characteristics of initial plasma, and obtain the extreme ultraviolet light with little dispersion and high intensity by providing a cylindrical insulator made of fine ceramic or the like of a device generating the ultraviolet light on the inside of an outside cylinder electrode. CONSTITUTION:A cylinder insulator 30 is inserted between the inside cylinder electrode 10 made of a conductor and the outside cylinder electrode 20 of a plasma extreme ultraviolet light generator, the high voltage is applied from a capacitor 50 to generate a capacitor pulse discharge. The gas corresponding to the usage objective such as Ne is sealed in a vacuum container 40. Plasma is self-heated by a large current generated by this discharge, plasma is pinched to generate the extreme ultraviolet light, it is guided into a reaction chamber 120 through a beryllium window 9 and reacted with a sample 130 to form a pattern. The rising time of the discharge is reduced, high intensity of the electron density is obtained, various characteristics of initial plasma are improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus that generates extreme ultraviolet light, and is particularly suitable for high-temperature and high-temperature applications such as ultraviolet light formation (exposure), thin film formation, oxidation, and etching, as well as microscopy and the like. This invention relates to an extreme ultraviolet light generation device using density plasma.

[Conventional technology]

A conventional X-ray generating device for extreme ultraviolet light was developed in Japanese Patent Application Laid-open No. 1983
As described in No.-206753, it was as shown in Figure 2. That is, the inner cylindrical electrode (negative polarity) 1 and the outer cylindrical electrode (positive polarity) 2 were separated by the cylindrical insulator 3 provided on the surface of the inner cylindrical electrode 1. Here, 4 is a discharge vessel, 5 is a capacitor, 6 is a switch, 7 is a discharge space, 8 is a magnetic pole, 9 is a beryllium window, 10 is a coil, 11 is a shield, 12 is an exposure chamber, and 13 is a wafer.

[Problem to be solved by the invention]

The above conventional technology does not give sufficient consideration to physical quantities such as initial plasma rise time, density, and energy, and has problems such as variations in X-ray intensity due to variations in each pulse discharge and lack of its absolute value. Ta.

An object of the present invention is to provide an excellent plasma extreme ultraviolet light (wavelength: about 1 to 3000) generator that solves the above problems.

[Means to solve the problem]

The above object is achieved by providing a cylindrical insulator 3o made of fine ceramics or the like on the inner surface of the outer cylindrical electrode 20, as shown in FIG.

[Effect]

The cylindrical insulator 30 is connected to the outer cylindrical electrode (positive polarity) 2
When provided on the inner surface of 0, the inner cylindrical electrode (negative polarity) 10
A creeping discharge is formed between the end surface 1O-1 (preferably made of a material with a small work function) and the outer cylindrical electrode 20 via the cylindrical insulator 30 in the forward direction (in the middle direction in Figure 1). , in the prior art, in the opposite direction), and the surface area of the cylindrical insulator 30 increases (because the radius ratio increases).

As a result, the rise time of the discharge is fast and its variation is reduced, and the generated electrons are accelerated toward the cylindrical insulator 30 by the potential between the two electrodes, and a larger amount of secondary electrons are emitted. However, a very high density electron layer is uniformly formed on the surface of the cylindrical insulator 30. The electron layer formed in this manner is accelerated toward the open end of the acceleration space 140 (in the middle direction in FIG. 2), generating a higher temperature and higher density initial plasma.

As the initial plasma grows, the plasma current increases, and this current also increases the self-magnetic field, so the plasma is self-compressively heated (pinched), and the effective compression is also larger than before, so it can be heated to ultra-high temperatures. - High-density plasma is generated in the discharge space 7. At this time, extreme ultraviolet light is emitted in a larger amount (higher brightness) with better reproducibility depending on the type (mass) of the gas used.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 3.

FIG. 1 shows a first embodiment of the present invention, 10 is W-Cu
an inner cylindrical electrode (usually negative polarity) made of a conductor such as an alloy;
10-1 is a low work function conductor (optional) made of LaBe or the like attached to the inner cylindrical electrode, 20 is an outer cylindrical electrode (usually positive polarity) made of a conductor such as Cu, and 30 is alumina, fine ceramics, etc. A cylindrical insulator consisting of a cylindrical insulator that insulates between the two electrodes and acts as a good source of secondary electron emission. 40 is a vacuum container made of stainless steel, etc., and 50 is a capacitor (1 to 10 μF).
Energy source with withstand voltage of 100KV, 6 is a low inductance switch (main discharge air gap switch),
6-1 is a crowbar (short circuit) switch, 7 is a discharge space, 8
is a magnetic pole that reduces the impact of high-speed electrons on the beryllium window 9. 100 is an electromagnetic coil 11 for magnetizing the magnetic pole 8 is a shield case, 120 is a reaction chamber, 130
140 indicates a sample, and 140 indicates an acceleration space.

In operation, the inner cylindrical electrode 10 and the outer cylindrical electrode 20
A high voltage is applied from the capacitor 50 between the cylindrical insulator 30 and a capacitor pulse discharge. (If necessary, the crowbar switch 6-1 may be operated to short-circuit the circuit.) At this time, the inside of the vacuum container 40 is filled with Ne (when soft X-rays are generated).
It is filled with a rare gas or the like at 0.1 to 100 Torr to obtain extreme ultraviolet light of a wavelength depending on the purpose of use.

Due to the large current generated by this discharge, the plasma is self-compressively heated and generates extreme ultraviolet light such as soft X-rays.

This light is transmitted to the reaction chamber 1 through the beryllium window 9, for example.
20 and react with the sample (wafer) 130 to form a bump or the like.

Further, after the inside of the reaction chamber 120 is evacuated to a high vacuum using an exhaust device, a reaction gas or ultrafine particles are introduced depending on the purpose such as etching or deposition, and a photoreaction effect with the extreme ultraviolet light is used. Samples can be processed or surface treated, and new materials can also be created. In order to select the wavelength of light, a filter is provided at the entrance of the reaction chamber 120 in place of the beryllium window 9. In this case, although not shown in FIG. 2, means for heating or cooling the sample 130 is provided.

FIG. 3 shows another embodiment. The second embodiment is characterized in that a multi-cusp magnetic field is superimposed on the outside (or inside) of the vacuum container 40. This multi-cusp magnetic field is 1
For example, as shown in FIG. 3(b), an even number of rod-shaped permanent magnets 150 with different polarities are alternately arranged (steady state), and a current is alternately applied to the even number of conductors so that the direction of the current is reversed. Flow and form. At this time, it is preferable to flow a pulsed current to form a pulsed magnetic field. By superimposing a multi-cusp magnetic field in this way, plasma can be stably generated and maintained, and the dose of extreme ultraviolet light can be increased. Other parts are the same as in FIG.

The cylindrical insulator 30 may be embedded so that its inner surface is flush with the inner surface of the outer cylindrical electrode 20, as shown in FIG. 3(A), and the shape is not particularly limited. isn't it.

In addition, in these embodiments, by discharging CH4 or the like in advance and coating the inner wall of the vacuum vessel 40 with a carbon film, it is possible to reduce the incorporation of impurities due to damage to the vacuum vessel 40, etc. This can reduce the increase in dose and its variation.

Furthermore, in the above embodiment, even if the polarities of the inner and outer picture electrodes are reversed, the device can be used as an extreme ultraviolet light generating device.

〔Effect of the invention〕

According to the present invention, one cylindrical insulator 3o is connected to an outer cylindrical electrode 20.
By providing it on the inner surface of the
It is possible to improve various characteristics of the initial plasma, such as increasing the electron density (several 10% or more) and increasing the electron density (30% or more), and obtain extreme ultraviolet light with high brightness (more than 50% increase compared to conventional products) with little variation. be able to.

Further, by superimposing multi-cusp magnetic fields, even more stable high-intensity extreme ultraviolet light can be obtained.

Furthermore, as brightness increases, filters and reaction chambers are installed to create new materials, including microfabrication and surface treatment by etching and deposition, using the photoreaction effect of the extreme ultraviolet light with reactive gases. It also has the effect of

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a plasma extreme ultraviolet light generator according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of a conventional plasma soft X-ray generator, and FIG. 3 is a longitudinal sectional view of another embodiment of the present invention. They are (a) a partial longitudinal cross-sectional view and (b) a cross-sectional view of the plasma extreme ultraviolet light generator. 1.10... Inner cylindrical electrode, 2.20 Outer cylindrical electrode, 3... Insulator, 3o... Cylindrical insulator, 4...
Discharge vessel, 4o... Vacuum vessel, 5,5o... Capacitor, 6... Switch, 6-1... Clover switch, 7... Discharge space, 9... Beryllium window, 120
...Reaction chamber, 130...Sample, 140...Acceleration space, 150...Maruji 111 No.

Claims (1)

[Claims] 1. In a plasma focus type X-ray generator comprising at least a coaxial inner cylindrical electrode and an outer cylindrical electrode, a cylindrical insulator is provided on at least a part of one end of the inner surface of the outer cylindrical electrode, means for applying a pulse voltage between the inner cylindrical electrode and the outer cylindrical electrode to generate plasma, and pinching the plasma by a self-magnetic field caused by a current flowing through the plasma; A plasma extreme ultraviolet light generator characterized by generating ultraviolet light. 2. The plasma extreme ultraviolet light generating apparatus according to claim 1, wherein a multi-cusp magnetic field is superimposed in the plasma extreme ultraviolet light generating apparatus according to claim 1.