JPS622700B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge plasma
The present invention relates to devices for preventing or reducing adhesion and electron bombardment.

Recently, it has been developed to use a discharge plasma X-ray generator as an X-ray source to project and transfer a fine mask pattern onto a wafer using soft X-rays that are relatively easily absorbed by the generated atmosphere.

FIG. 1 shows a conceptual diagram of a discharge plasma X-ray generator.

In the figure, when a negative high voltage is applied to the -HV point with switch 1 closed and switch 2 open, electrical energy is stored in capacitors C1 and C2 through resistor R1. After the energy reaches a predetermined value, when switch 1 is opened and switch 2 is closed, the energy (charge) stored in the capacitor C1 is discharged between the first electrode 3 and the second electrode 4. consumed. At this time, the material of the insulator 5 (polyethylene, etc.) evaporates, and a plasma state P is achieved. Due to changes in the potentials of the first electrode 3 and cathode 6 due to this discharge, changes in electric field distribution due to plasma generation, etc., a discharge of the charge stored in the capacitor C2 is then generated from the cathode 6. This becomes an electron beam and causes coupling with plasma. This coupling increases the energy of the plasma ions and also increases the plasma density, resulting in the emission of X-rays in addition to infrared and ultraviolet light.

FIG. 2 shows the configuration of an X-ray transfer device using the discharge plasma X-ray generator shown in FIG. 1 as an X-ray source.

In the figure, a support 10 with high X-ray transmittance and an absorber 1 with low X-ray transmittance are placed between sample a, which has an X-ray photoresist 8 coated on a substrate 7, and an X-ray source 9.
1 and a support frame 12 that supports a support body 10 is arranged. When the mask b is irradiated with X-rays, a latent image of the pattern of the absorber 11 is formed on the X-ray resist 8 by the X-rays transmitted through the portion where the absorber 11 is not present. This is X-ray exposure, and a resist pattern is then formed on the substrate 7 by developing the resist.

In the above X-ray irradiation, the X-ray source 9 used emits plasma substances such as ions, electrons, neutral atoms, and electron beams, and the mask b is used many times in the case of mask exposure. As a result, these substances accumulate on the surface of mask b, impairing the X-ray transmittance of mask b. For this reason, some devices have conventionally placed an X-ray transparent thin film C made of a polymeric material between the X-ray irradiation surface (mask b) and the X-ray source 9.
However, although this thin film C allows X-rays to pass through, its transmittance is low.
There is no such thing as 100%, and the actual transmittance is around several tens of percent, so the intensity of the X-rays is low. Furthermore, if the thin film C is left as it is and exposed many times, plasma substances will adhere to it, similar to the above-mentioned mask, resulting in a disadvantage of attenuation of the X-ray dose on the irradiated surface.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus that prevents or reduces the impact and adhesion of plasma material to an irradiation surface without placing anything between the X-ray source and the irradiation surface that would reduce the X-ray transmittance. .

The features of the present invention include an X-ray generator, and a deflection plate or magnetic field deflector that applies an electrode and high voltage when a high-frequency high voltage is introduced between the X-ray generator and the X-ray irradiation surface, Neutral atoms in the plasma are ionized by the electrode that introduces the high frequency and high voltage, and the ionized atoms and ions and electrons from the plasma are irradiated with the ionized atoms and the ions and electrons from the plasma using a deflection plate or a magnetic field deflector that applies the high voltage. The above objective is achieved by directing it out of the plane.

Hereinafter, the present invention will be described with reference to an embodiment. FIG. 3 shows an embodiment in which the course of charged particles is changed by a deflection plate applied to an X-ray transfer apparatus according to the present invention.

In the figure, a deflection plate 13 is provided between the X-ray source 9 and the irradiation surface (mask b), and a trap 14 is further provided around the outer periphery of the mask b.

The discharge plasma X-rays emitted from the X-ray source 9 include plasma substances such as ions, electrons, neutral atoms, and electron beams emitted from the source. These ions and electrons are given kinetic energy in a direction perpendicular to the optical axis by a deflection plate 13 to bend the course of these particles and direct them toward the trap 14 instead of toward the mask surface b.

However, since neutral atoms have no electric charge, the deflection plate 13 does not work. Therefore, as shown in FIG. do. The principle of ionization is as follows.
When a high frequency wave acts on the neutral atom, the electrons and ions (the parts of the neutral atom from which electrons have been removed) have different response speeds to the electric field, resulting in different vibrational modes, and as a result, the neutral atom is separated into electrons and ions. do. The path of the neutral atoms thus ionized is bent by the deflection plate 13 and directed toward the trap 14.

FIG. 5 shows a perspective view of the structure of the high frequency introduction electrode and deflection plate described above.

Also, the relationship between the high frequency introduction electrode and the deflection plate is as follows.
As shown in the figure, the deflection plate 13 may be placed with the irradiation surface side (mask b) facing.

Note that instead of the deflection plate 13, a deflector using a magnetic field may be used.

In the present invention, in order to prevent plasma ions, neutral atoms, and electrons from adhering to the mask, an X-ray transparent thin film is not disposed between the X-ray source 9 and the mask b.
The high-frequency introduction electrode 14 and the deflection plate 13 are arranged to change the course of plasma ions, neutral atoms, and electrons so that they do not go toward the mask b, so the X-ray dose is not attenuated and the dose is used effectively. , the fluctuation in exposure amount can be reduced.

According to the present invention as described above, it is possible to provide an X-ray transfer apparatus that makes effective use of the X-ray dose and has little variation in the exposure dose, which has great practical effects.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram for explaining the discharge plasma X-ray generator, and Figure 2 is the discharge plasma X of Figure 1.
FIG. 1 is a conceptual diagram for explaining the configuration of a conventional X-ray transfer device using a ray generator as an X-ray source. 3rd to 4th
The figure is a sectional view for explaining one embodiment of the X-ray transfer device according to the present invention, FIG. 5 is a perspective view showing the structure of the high frequency introduction electrode and deflection plate according to the present invention, and FIG. 6 is the high frequency introduction according to the present invention. FIG. 7 is a cross-sectional view showing another example of the arrangement of electrodes and deflection plates. In the figure, 9 is an X-ray source, 13 is a deflection plate, 14 is a trap, and 15 is a high frequency introducing electrode.

Claims (1)

[Scope of Claims] 1. In a tube consisting of two discharge electrodes and an insulator sandwiched between them, an electric discharge is generated by both electrodes, and an electron beam is injected into the tube.
a discharge plasma X-ray generator that generates a
Between the ray generator and the X-ray irradiation surface, an electrode for introducing high frequency and high voltage and a deflection plate or a magnetic field deflector for applying high voltage are provided, and the electrode for introducing high frequency and high voltage is used to introduce the high voltage into the plasma. A certain neutral atom is ionized, and ions and electrons from the ionized atoms and plasma are directed to a position away from the irradiation surface using a deflection plate applying a high voltage or a deflector using a magnetic field. Characteristic X-ray transfer device.