JPS6326931A - Gas plazma x-ray generator - Google Patents

Abstract

PURPOSE:To prevent a beryllium membrane from damage caused by neutral particles or charged particles by discharging a gas from a gas stream generating means in the direction orthogonal with the direction in which X rays are radiated from pinch plazma. CONSTITUTION:A high speed gas stream generating means 30 is provided, and it is preferable that the second high speed gas valve 32 is opened to discharge a gas in synchronization with the time when pinch plazma 10 is generated. That is, after the time delay caused by a delay circuit 23 during which a pulse current is sent to a valve power source 24 from a trigger source 22, and the first high speed gas valve 7 is opened to discharge Ne-gas via a gas path 8 of a first electrode 4, a pulse is applied to a discharging electrode of a discharging switch 27 by a high voltage trigger source 25 to make it be in discharge condition. And when the resistance of the discharge switch is made zero, the charge charged in a capacitor 26 connected between the first and second electrodes 4 and 3 is discharged so as to make a cylinder-shaped gas 9 be pinch plazma 10 then radiate X rays 11. The time of the second delay circuit 36 is decided so that the second high speed gas valve 32 can be opened at the moment X rays are radiated, not to cause damage to a beryllium membrane.

Description

[Detailed Description of the Invention] [Summary of the Invention] The present invention! To prevent the beryllium thin film that forms the X-ray extraction window from being destroyed by neutral particles and charged particles generated along with X-rays in gas plasma X-ray generators used in lithography technology during the manufacture of A-product circuits. , a gas plasma in which only X-rays are directed toward the X-ray extraction window by emitting high-speed gas that does not absorb X-rays from a direction perpendicular to the X-ray emission direction and dissipating neutral particles and charged particles. The present invention provides an X-ray generator.

[Industrial application field]

The present invention relates to a gas plasma X-ray generator, and more particularly to a high-speed gas discharge means for preventing damage to an X-ray extraction window of an X-ray generator used in an exposure apparatus for integrated circuits.

With the increasing integration and speed of semiconductor integrated circuits, the projection exposure limit has become 1 to 2 μm, and the wavelength of soft X-rays, which is 4 to 12 μm, is shorter than the wavelength of ultraviolet rays, so it is superior in terms of diffraction and interference.
Although X-ray exposure technology has been proposed, development of X-ray sources, masks, resists, etc. is required, and there is a desire to establish process technology using X-ray exposure.

[Traditional techniques]

The plasma ray source used in gas plasma X-ray generators uses soft X-rays generated from high-temperature, high-density plasma through bremsstrahlung radiation, recombination radiation, etc. Plasma formation methods include laser excitation,・Gas plasma is used outside the array.

The conventional structure of such a gas plasma X-ray generator will be described in detail with reference to FIG. Figure 4 shows conventional gas plasma
1 is a schematic side sectional view of the ray generator, in which 1 shows the gas plasma X-ray generator as a whole, the vacuum volume R52 is called a normal chamber and is configured in a cylindrical shape, and the upper part is integrated with the vacuum container 2. The second
An electrode 3 is provided concentrically with the vacuum vessel 2, and a first electrode 4 is airtightly disposed inside the second electrode 3 via a ring-shaped insulator 5. The first electrode is composed of a cylindrical member, and a gas passage 8 is provided inside the first electrode, and a gas passage 8 formed in a cylindrical shape is connected to a second gas passage through a gas introduction pipe 6 and a first high-speed gas valve 7. Release gas into subject 3. Reference numeral 9 indicates gas discharged from the gas passage 8 which serves as both the cylindrical first electrode and the hollow nozzle 4, and 10 indicates pinch plasma, which will be described later. Second electricity (hired 3
There is an aperture 12 at the bottom for passing X-rays 11.
Further, a plasma reflecting means 13 is provided at the lower end of the second electrode 3, and the plasma reflecting means is provided with an inclined member 14 that is inclined with respect to the bottom of the second electrode 3, and also has an aperture 15. It is bored into the inclined member. The X-rays 11 that have passed through the aperture 15 of the plasma reflector 113 pass through the X-ray extraction window 17 formed at the bottom of the vacuum container 2' and pass through the X-ray mask 20 to expose the sample +"-121. Approximately 25 mm is placed in the take-out window 17 to pass the X-ray.
A beryllium film 18 made of a thin film of μm or less is stretched,
Deflection means 1 for removing charged particles is installed at the entrance of the X-ray extraction window.
6 are arranged.

Note that 19 is a vacuum pump for maintaining the inside of the vacuum container 2 in an optimal vacuum state.

In the above vacuum container structure, the first and second electrodes 4.
A series circuit of a capacitor 26 and a discharge switch 27 is connected between the capacitor 26 and the discharge switch 27, and the capacitor 26 discharges the first voltage 1N by closing the discharge switch 27 with a main discharge capacitor.
A discharge is caused between +4 and the second electrode 3 to cause a discharge current to flow.

The pulp power supply 24 is operated by the power from the trigger source 22, the first high-speed gas valve 7 is opened, and a gas such as neon (Ne) gas introduced from the direction shown by arrow A is supplied to the first high-speed gas valve 7.
The gas passage 8 of the first electrode 4 through the high-speed gas valve 7 of
Gas is released from inside the second electrode 3.

In synchronization with this gas release, a trigger from the trigger source 22 is applied to the high voltage trigger source 25 via the first delay circuit 23, and discharge is performed based on the current. That is, the gas discharge and the discharge voltage applied to the first and second electrodes operate intermittently.

[Problem to be solved by the invention] The above configuration solves the first problem. The Ne gas intermittently released from the Ii+M gas passage 8 is released in a cylindrical shape, but due to the discharge current at this time, the gas converges to the center due to the movement according to the Flaming law, forming a pinch plasma 10. This pinch plasma 10 is a plasma with a diameter of 1 dragon, which uses Ne gas, has a wavelength of 12 people, and an output of 150 JKr gas, and has a wavelength of 7 people, and an output of about 25 J, although it varies depending on the gas flowing in and the wavelength. X-rays 11 are emitted due to braking or recombination radiation from the pinch plasma 10, but neutral particles 28 and charged particles 29 made of plasma droplets and electrode scattering from the pinch plasma 10 collide with the beryllium film 18 made of a thin film. There is a problem in that it causes damage and even destruction. The charged particles 29 are deflected from the beryllium film 1 by the deflection means 16 provided at the entrance of the X-ray extraction window 17.
By colliding with the side wall of the X-ray extraction window 17 and absorbing the charged particles before the charged particles reach 8, it is possible to remove the charged particles to some extent. However, the neutral particles 28 are reflected and absorbed by the inclined member 14 of the plasma reflection means 13, but the neutral particles 28 that have passed through the aperture 15 completely hit the beryllium film 18 and are sufficiently removed. There was a drawback that I couldn't do it.

[Means for solving problems]

The present invention was made in view of the above-mentioned drawbacks of the conventional art, and its purpose is to provide a high-speed gas flow discharge means that prevents neutral particles from damaging the beryllium film provided in the X-ray extraction window, and to The charged particles are scattered by a gas flow, and the means for doing so includes a first electrode that is placed in a vacuum container and also serves as a gas injection nozzle, and a second electrode that is placed opposite to the first electrode. It has an electrode, a gas injection means for intermittently injecting gas into the first electrode, and a discharge means for causing a discharge between the first and second electrodes. In the X-ray generator, a pinch plasma is generated between the second electrode and the X-ray emitted from the pinch plasma is extracted from the X-ray extraction window provided in the above-mentioned vacuum container. Gas plasma X-ray generation characterized in that it has a high-speed gas flow generation means arranged between the gas flow generation means and discharges gas from the gas flow generation means in a direction perpendicular to the X-ray emission direction from the pinch plasma. achieved by the device.

[For production]

The gas plasma X-ray generator of the present invention scatters only neutral particles and charged particles other than the X-rays generated from the pinch plasma, and the X-rays are made of helium gas, etc., which is not absorbed by the emitted gas. The rays are extracted through the X-ray extraction window, and the beryllium film is not damaged by neutral or charged particles.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. Fig. 1 is a schematic diagram of the gas plasma FIG. 3 is a timing waveform diagram showing the timing of trigger pulses applied to the high-speed valve and discharge switch of the line generator.

In the configuration of FIG. 1, the same parts as those in FIG. 4 are given the same reference numerals and redundant explanation will be omitted, but a high-speed gas flow generating means 3o is provided on the side wall of the vacuum volume 2''J2.

The high-speed gas flow generating means 30 is disposed between the bottom of the second electrode 1 and the X-ray extraction window 17 formed at the bottom of the vacuum vessel 2. The first stage 30 of high-speed gas flow generation is a gas tank 31
A gas that does not absorb X-rays, such as He (helium) gas, is discharged from the through hole 34 of the nozzle 33 through the gas introduction pipe 35 and the second high-speed gas valve 32 . The nozzle 33 extends to the vicinity of the X-ray emission path of the vacuum container 2 and collects neutral particles 28 scattered from the pinch plasma 10.
Blow away two charged particles, plasma droplets 38, etc. as indicated by the arrows. For this purpose, the second high-speed gas valve 32 is
In order to turn on the valve, the voltage of the trigger source 22 is applied through the second delay circuit 3G and the valve power supply 3'7.

As shown in FIG. 2, the second high-speed gas valve 32 has a trap section 39 between the gas introduction pipe 35 and the nozzle 33, and a disk-shaped valve 42 made of non-magnetic aluminum or the like is disposed within the trap section. A biasing force to close the gas introduction pipe 35 is applied by a spring 41 provided therein. The magnetic field generated by passing a current from the pulp ff1N3'y to the solenoid 40 generates an eddy current in the disc-shaped valve 42, pushing the valve 42 in the direction shown by the dashed line against the biasing force of the spring 41, and opening the gas tank. He gas from 31 is transferred to nozzle 33
It is discharged into the vacuum container 2 through the through hole 34 .

The second high-speed gas valve 32 is opened (in order to enable the gas to be released in synchronization with the point in time when the pinch plasma 10 is generated). After the first delay circuit 23 takes a time of about 100 μ3 for the first high-speed gas valve 7 to open and Ne gas to be released from the gas passage 8 of the first electrode 4 by applying the current P1, the high voltage trigger is activated. A pulse P2 shown in FIG. 3(b) is applied from the source 25 to the discharge electrode of the discharge switch 27 to bring it into a discharge state, and the resistance of the discharge switch is made zero, thereby creating a capacitor 2 between the first and second electrodes 4.3.
The charges stored in the gas 6 are discharged, and the cylindrical gas 9 becomes a pinch plasma 10 and emits °ζ X-rays 11. The amount of delay of the second delay circuit 36 is determined so that the second high-speed gas valve 32 is opened at the moment the gas is released. These values will be determined experimentally, and will take approximately 100 na. That is, the second high-speed gas valve 32 is opened by the current pulse P3 in FIG. 3(C).

In the embodiment shown in FIG. 1, a case has been described in which the plasma reflecting means 13 shown in FIG. 4 is not provided, but this means can be provided together with the high-speed gas flow generating means of the present invention if necessary.

〔Effect of the invention〕

Since the present invention is constructed and operated as described above, neutral particles, charged particles, hurrahs, etc. generated when X-rays are generated can be eliminated.
A gas plasma X-ray generator that blows off droplets and does not damage the beryllium film of the X-ray extraction window can be obtained.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the gas plasma X-ray generator of the present invention, Fig. 2 is a side sectional view of the high-speed gas nozzle used in the present invention, Fig. 3 (al, (b), (C) ) is a waveform diagram showing the timing of the high-speed gas nozzle < ) rev and discharge switch pulse of the present invention, and FIG. 4 is a schematic diagram of a conventional gas plasma X-ray generator. DESCRIPTION OF SYMBOLS 1... Gas plasma generator, 2... Vacuum container, 3... Second electrode, 4... First electrode, 5... Insulator, 6... Gas introduction tube, 7. ...First high-speed gas valve, 8...Gas passage, 9...Gas, 10...Pinch plasma, 11...X-ray, 12...Aperture, 7 13...Plasma reflecting means, 14... Diagonal member around 1, 15... Aperture, 16... Deflection means, 17... X-ray extraction window, 18... Beryllium membrane, 19... Vacuum pump, 20... Mask , 21... Sample, 22... Trigger source, 23... First delay circuit, 24... Pulp power supply, 25... High voltage trigger source, 26... Capacitor, 27... Discharge switch, 28... Neutral particles, 29... Charged particles, 30... High speed gas flow generating means, 31... Gas tank, 32... Second high speed gas valve, 33... Nozzle , 34... Through hole, 35... Gas introduction tube, 36... Second delay circuit, 37... Pulp power source, 38... Plasma droplet, 39... Trap section, 40... ·solenoid. Patent applicant: Fujitsu Limited
figure

Claims (4)

[Claims] (1) A first electrode 4 which also serves as a gas injection nozzle and which is placed in the vacuum container 2, a second electrode 3 which is placed opposite to the first electrode, and which is intermittently connected to the first electrode 4. It has a gas injection means for injecting a gas, and a discharge means for generating a discharge between the first and second electrodes, generates a pinch plasma 10 between the first and second electrodes, and generates a pinch plasma 10 between the first and second electrodes. In the X-ray generator which extracts the emitted X-rays 11 from the means 30, said pinch plasma 10
A gas plasma X-ray generator characterized in that gas is emitted from the gas flow generating means 30 in a direction perpendicular to the direction in which the X-rays are emitted. (2) A synchronizing means is provided for synchronously flowing the gas discharged from the high-speed gas flow generating means 30 and the gas intermittently injected into the first electrode 4. Gas plasma X-ray generator. (3) Gas plasma X-ray generation according to claim 1, characterized in that the gas discharged from the high-speed gas flow generating means 30 is a gas that does not absorb the X-rays 11 generated from the pinch plasma 10. Device. (4) The gas plasma X-ray generator according to claim 3, wherein the gas that does not absorb the X-rays 11 is helium gas.