JPS61218056A - X-ray generator - Google Patents

Abstract

PURPOSE:To stably and reliably control switching of the movable valve of a high-speed switching gas valve with simple structure and minimize the variation in switching operation by using electromagnetic force to switch the movable valve. CONSTITUTION:A plasma production chamber 10 is usually maintained at a proper vacuum by means of a vacuum pump 12. When gas 26 is fed into an X-ray generator by the operation of a high-speed switching gas valve 16, plasma is produced in a plasma production regions 13 located between a high voltage electrode 3 and a low voltage electrode 5. As the result, X-rays 15 are produced which are then led outside the generator through an X-ray discharge window 6. Electromagnetic force is used to move the movable valve 22 of the high-speed switching gas valve 16 upward during gas feeding thereby making the plasma production chamber 10 continuous with a gas chamber 25. Then, the valve 22 is moved back to its original position by its own weight thereby breaking the connection between the two chambers. Due to the above simple structure, the weight of the valve 22 can be reduced and the valve 22 can be driven by reduced force.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention generates plasma by flowing gas at high speed between electrodes arranged facing each other in a plasma generation chamber, and by passing a large current between the electrodes. This device relates to a device that generates light and X-rays using plasma, and has been improved to have a particularly simple structure and to obtain stable X-ray output.

[Conventional technology]

Conventionally, two main methods have been proposed for X-ray generation using discharge plasma. One of them is the plasma focus method (for example, Nuclear Fusion Research, Vol. 35, No. 6, P. 4).
28, June 1976, Nagoya University Plasma Research Institute), and the others are two-pinch methods, and the X-ray generator according to the present invention belongs to this two-pinch method. In order to transfer the integrated circuit pattern using X1IiI generated from these plasmas, X-rays with a wavelength (5 to 15 A) suitable for the material of the polymer film (resist) coated on the wafer are required.
This wavelength is determined by the characteristics of the supplied gas.

Conventionally, the two methods used to supply this gas include a method in which the gas is continuously supplied between a set of electrodes installed in a vacuum container, and a method in which the gas is supplied continuously at all times, and a method in which the gas is supplied using electromagnetic force or the force of a spring. There is a method in which the gas is flown in pulses only when necessary.

[Problem that the invention seeks to solve]

By the way, the plasma necessary to generate X-rays has a temperature of about 1 million to 10 million degrees Celsius or more and a plasma density of about 10
/c1n or more, it is necessary to create a generation formula in an extremely short time (for example, on the order of μm). For this purpose, it is necessary that the gas supply rate and initial gas density be stable, and l)
In a practical machine, the repetitive operation speed is thought to be several tens of Hz at most.

Taking these into consideration, continuously flowing gas into the vacuum container not only wastes gas, but also has the drawback of making the capacity of the exhaust system larger than necessary. On the other hand, the conventional gas valve system that allows gas to flow in pulses is placed laterally, so the gas valve is always closed using the force of a spring, and when necessary, an electromagnet is operated and the gas valve is opened using the suction force. The structure is complicated, the gas valve opens for several tens of milliseconds, so the operation is slow, and the operation is highly variable, so it has the disadvantage of lacking stability in generating high-temperature, high-density plasma.

[Means for solving problems]

The X@ generator according to the present invention has been developed in view of the above-mentioned points, and includes a pair of electrodes that are arranged facing each other in a plasma generation chamber and connected to the length of a condenser via a discharge switch. a plasma A high-speed opening/closing gas valve equipped with a movable valve that shuts off the gas and connects the gas chamber with the plasma generation chamber by being moved upward by electromagnetic force when gas is supplied, and falls under its own weight when returning from vomiting. It is.

[For production]

In the present invention, the movable valve is moved upward in a very short time using electromagnetic force to cause gas in the gas chamber to flow between the electrodes, and when the electromagnetic force disappears, the movable valve falls under its own weight, closing the high-speed opening/closing gas valve. With a simple structure, opening and closing can be controlled stably and reliably, and variations in operation can be reduced.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Figure fa1 is a sectional view showing an embodiment of the X-ray generator according to the present invention. 1 is a plasma X-ray source, and this plasma
The radiation source 1 includes an electrode member 2 having a high voltage electrode 3 and a low voltage electrode 5.
and an electrode member 4 having an X-ray extraction window 6. These electrode members 2゜4 are arranged vertically facing each other via a seal/insulating plate 7, and are connected via a discharge switch 9 to a plasma generation power source 8 that generates high voltage and large current, thereby generating plasma. Vacuum vessel 11 forming chamber 10
It consists of The plasma generation chamber 10 is normally maintained in an appropriate vacuum state by a vacuum pump 12, and when a gas 26 is supplied by the operation of a high-speed opening/closing gas valve 16,
Plasma is generated in the plasma generation section 13 between the high-voltage electrode 3 and the low-voltage electrode 5, and this plasma is pinched by the self-magnetic field as the electric current increases, thereby forming a plasma P, which generates X-rays 15 is generated, and the X-rays 15 are taken out to the outside through the X-ray extraction window 6.

The high-speed opening/closing gas valve 16 includes a container 20 placed on the upper surface of the electrode member 2 via an O-ring 17 and firmly fixed to the electrode member 2 with a plurality of bolts 18 . The inside of this container 20 is controlled to open and close by a metal movable valve 22 operated by a driving excitation coil 21, and normally the movable valve 22 is positioned on the electrode member 2 via an O-ring 23. The movable valve 2 is disconnected from the plasma generation chamber 10 when gas is supplied.
2 to form a gas chamber 25 that communicates with the plasma generation chamber 10.
The gas 26 is supplied from a gas injection hole 27.

Both ends of the driving excitation coil 21 are connected to the container 20,
For example, it is connected to terminals 28m and 28b fixed with resin, and these terminals 28m and 28b are connected to a gas valve pulse power source 29 via a discharge switch 30. The movable valve 22 is disposed within the gas chamber 25 so as to be able to move up and down, and its lower surface is normally brought into close contact with the O-ring 23 by the vacuum force of the plasma generation chamber 10, thereby separating the generation chamber 10 and the gas chamber 25. are kept airtight from each other.

Next, the operation of the X-ray generator 1 having such a configuration will be explained.

The gas 26 is supplied to the υ gas chamber 25 through the gas injection hole 27,
The chamber 25 is filled. In this state, the discharge switch 30
is closed, and the pulse power supply 29 for the gas valve sends an extremely steep large current to the excitation coil 2 for driving by means of electric discharge, etc.
1, a large magnetic flux 33 is generated in the mosquito coil 21, and the space between it and the movable valve 22 becomes subject to strong magnetic pressure. Then, the movable valve 22 is flipped upward by the magnetic repulsion force,
The gas injection hole 27 collides with the ceiling surface 20a of the container 20.
block. On the other hand, when the movable valve 22 moves upward, the wrinkle stretch 22
Since a gap was created between the gas chamber 25 and the O-ring 23 to allow communication between the gas chamber 25 and the plasma generation chamber 10, the gas filling the gas chamber 25 was kept in a vacuum state at a speed close to the speed of sound. It flows into the plasma generation section 13 of the plasma generation chamber 10. When the gas that has flowed in reaches a predetermined gas density, the discharge switch 9 is closed, and the plasma generation pulse power source 8 applies an extremely steep high voltage such as capacitor discharge between the high voltage electrode 3 and the low voltage electrode 5. As a result, the electric field strength between the electrodes 3 and 5 of the plasma generation section 13 is extremely strong.
Dielectric breakdown occurs and the gas becomes plasma. Then, the impedance of the circuit is reduced, and a large current I is supplied from the pulse power source 8, and the plasma undergoes a pinching action due to its own magnetic field and gradually converges to form a pinched plasma P with a diameter of about 1 to 2 tm. This generates X-rays 15. Thereafter, as the large current attenuates, the plasma gradually collapses and disappears when the current is cut off.

On the other hand, when the movable valve 22 operates and springs upward,
Since the above-mentioned inlet gas injection hole 27 is closed, the gas 26 does not flow into the gas chamber 25 while the movable valve 22 is open. By reducing the current flowing from the pulse power source 29 to the driving excitation coil 21, the electromagnetic force caused by the coil 21 decreases. Therefore, the movable valve 22 falls due to its own weight and the force applied by the pressure difference generated between the vicinity of the flange 22A of the wrinkle extension 22 and the gas chamber 25, contacts the O-ring 23, and then the vacuum force of the plasma generation chamber 10 As a result of being attracted by the gas, it is brought into close contact with the O-ring 23, and the communication between the plasma generation chamber 10 and the gas chamber 250 is cut off. That's book X
This is the operating principle of the line generator.

Conventional high-speed opening/closing gas valves used in plasma research are installed horizontally, and the movable valve is always pushed in one direction by the force of a spring. It was released using electromagnetic force. Therefore, the structure is complicated because it requires a spring, and the weight of the movable valve is more than an order of magnitude heavier than the movable valve 22 made by the device of the present invention, which has the disadvantage of requiring strong electromagnetic force due to large-capacity capacitor discharge. Furthermore, as the electromagnetic force becomes stronger, the drive mechanism may fail and the drive excitation coil may be damaged due to Joule heat, leading to problems in terms of service life.

In contrast, in the present invention, the high-speed opening/closing gas valve 16 is installed vertically, the movable valve 22 is arranged to be movable in the vertical direction, and after the movable valve 22 is moved upward by the electromagnetic force of the driving excitation coil 21, the recovery operation is performed on the valve. Since the movement is performed by the weight of the 22 itself, no spring is required and the structure is simple. Further, even if the movable valve 22 is made of metal, for example aluminum, it can be made of 502 mm or less, and the electromagnetic force of the excitation coil 21 for driving can be small since it is extremely lightweight and can be made of a metal such as aluminum. Since the power supply 29 also requires a small capacity, the temperature rise in the circuit is small, and the high-speed opening/closing gas valve 1B can be made into the above-mentioned easy-to-operate structure, so it has excellent durability and a long service life compared to conventional devices. can solve the problem.

In this case, the movable valve 22 does not need to be made entirely of metal;
The flange 22A of the movable valve 22 is made of metal, and the driving excitation coil 2
Since it is sufficient to prevent the penetration of the magnetic flux 33 of No. 1 and generate a repulsive force due to electromagnetic force, the columnar main body 22B may be made of plastic. Therefore, a movable valve with such a combination is manufactured and used. In particular, it is possible to further reduce the weight.

In this way, XIi! according to the present invention! The generator is a movable valve 2
The lighter weight of 2 enables high-speed driving, and the gas injection hole 27
Since the inflow of gas 26 is temporarily stopped by the blockage of The gas density can be rapidly reduced, and the reproducibility is also very good.

If the operation of the movable valve 22 is slow, the joint surface with the O-ring 23 will not peel off slowly, resulting in a large initial resistance when gas flows in, resulting in a sloppy gas flow. Therefore, the plasma generation section 13 does not reach a predetermined gas density immediately, and the gas diffuses throughout the plasma generation chamber 1G, so that no discharge occurs in the plasma generation section 13, and in extreme cases, discharge occurs on the surface of the insulating plate 70. It turns out. Moreover, if the gas injection hole 2T is not closed, the gas 26 will continue to flow in even if the plasma generation part 13 reaches a predetermined pressure, and more gas than necessary will flow in, causing the vacuum pump 1
2, it will take time to exhaust the air.

In the embodiment shown in FIG. 1, the electrode member 4 also serves as a vacuum vessel 11 for forming the plasma generation chamber 1°, and is equipped with an Xfs extraction window 6, etc., but the low-voltage electrode 5 is separate and independent from the electrode member. It is also possible to connect it to the pulse power source 8 for plasma generation.

An example is shown in FIG. FIG. 2 also shows another embodiment of the high-speed opening/closing gas valve. That is, in this embodiment, a vacuum container 40 equipped with an X-ray extraction window 6 is manufactured separately from the low-voltage electrode 5, and the low-voltage electrode 5 is inserted into the upper opening of the vacuum container 40.
is disposed thereon, and an electrode member 2 is further disposed thereon via an insulating plate 7 to form a plasma X-ray source 1. A movable valve 22 is formed of a metal plate, and its lower surface is connected to an O-ring 41 to form a plasma generation chamber. 1
A high-speed opening/closing gas valve 16 which normally cuts off the communication between the nine gas chambers 25 and the plasma generation chamber 1 degree is installed above the gas chambers 25 and 1 degree.
□ Since the other configurations are the same as those of the embodiment shown in FIG. 1, they are designated by the same reference numerals and their explanations will be omitted. Further, the operation of the high-speed opening/closing gas valve 16 and the generation and generation of X-rays 9 are also the same as in the above embodiment, so their explanation will be omitted.

Here, the difference from the apparatus of the embodiment shown in FIG. 1 is that the shape of the movable valve 22 is simpler and lighter, and the operation is very good.

In addition, in the present invention, although the shape of the plasma generation section 13 is shown as a very simple example, in order to generate the pinch plasma P, conditions determined by the electrode shape, the type and density of gas, the magnitude of the current, etc. Various combinations often occur, but which method can be used to supply the gas 26 in a temohalus manner and generate plasma? The present invention can be effectively applied to any method as long as a method for obtaining light or X-rays is used.

In addition, the X-ray generator of the present invention includes an X-ray analyzer, an X-ray microscope, and a chemical reaction device using X-ray excitation.

It can be applied to a film forming apparatus that uses X-ray excitation and an etching apparatus that uses X-ray excitation.

〔Effect of the invention〕

As explained above, the X-ray generator according to the present invention has a high-speed opening/closing gas valve disposed in the plasma X-ray source, and the movable valve is moved upward by electromagnetic force when gas is supplied, thereby generating plasma. Since the chamber and the gas chamber are communicated with each other, and the communication between the two chambers is cut off by returning the chamber by its own weight, the structure is simple, the weight of the movable valve can be reduced, and the driving force of the movable valve can be reduced. be able to. As a result, the electromagnetic force is small, making it possible to reduce the capacity of the pulse power supply, and also making it extremely easy to design the electromagnetic force and thermal design of the excitation coil for driving the gas valve, making it possible to miniaturize the device itself. . Furthermore, since the movable valve can be operated quickly and stably, the gas density in the plasma generation section can be reproducibly obtained, and therefore X-rays can be obtained with good reproducibility.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the invention, and FIG. 2 is a sectional view showing another embodiment of the invention. 2.4... Electrode member, 3... High voltage electrode, 5...
...Low voltage electrode, 8...Plasma generation pulse source,
9...discharge switch, 10...plasma generation chamber, 11...vacuum container, 12...vacuum pump, 1
3...Plasma generation section, 15...X-ray, 16...
...High-speed opening/closing gas valve, 20... Container, 21.
... Drive excitation coil, 22... Movable valve, 25.
... Gas chamber, 26 ... Gas, 29 ... Pulse power supply for gas valve, 30 ... Discharge switch.

Claims (1)

[Claims] A plasma X-ray source having a pair of electrodes disposed facing each other in a vacuum container forming a plasma generation chamber and connected to a capacitor via a discharge switch is in communication with the plasma generation chamber and supplied with a predetermined gas. a container having a gas chamber;
It is arranged in this container so as to be able to move up and down, and normally blocks communication between the plasma generation chamber and the gas chamber, and is moved upward by electromagnetic force when gas is supplied, thereby connecting the gas chamber to the plasma generation chamber. An X-ray generator characterized by having a high-speed opening/closing gas valve equipped with a movable valve that communicates and falls under its own weight when returning.