JPS62141721A - Charged particle device - Google Patents

Abstract

PURPOSE:To realize large-space radiation which is simple in constitution, superior in parallelism and high in performance, by moving a balanced orbit of charged particles in up and down directions and in parallel. CONSTITUTION:After prescribed charged particles are accumulated in an accumulation ring 1, the accumulation ring is moved up and down in accordance with an operation cure set in advance by movable mechanism 14. Then, up and down directional motion of the accumulation ring 1 serves for utilizing parallelism of radiated light beam lines. Necessity in the said motion is moving the whole in parallel without changing mutual positions among a deflecting electromagnet 3, a four-poled electromagnet 9 and other orbital electromagnets, which are constituents of the accumulation ring 1. Therefore, the accumulation ring 1 is fixed on a common board 13 and this board 13 is vibrated in up and down directions by hydraulic pressure control.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a charged particle device.

More specifically, it is related to a charged particle device that utilizes a synchrotron radiation (SOR) beam, which accelerates charged particles such as an electron beam, accumulates them, and generates them from a deflection section. It is.

[Conventional technology]

FIG. 5 is a plan view showing an example of a conventional charged particle device used for exposing semiconductors. In the figure, (1) is a storage ring that stores charged particles for a long time.

In this example, if the charged particles entering from the entrance part (2) have already been accelerated to a predetermined energy,
However, the same applies to the case where incident particles are incident with energy lower than a predetermined energy, and after the incident particles are accelerated and accumulated. (3) is a deflecting electromagnet for deflecting charged particles to form an equilibrium orbit (4). (5) is a synchrotron radiation beam line for extracting and utilizing the synchrotron radiation generated when the charged particles are deflected. Although the synchrotron radiation beam line (5) is shown as a single synchrotron radiation beam line in the figure, it is usually composed of a plurality of synchrotron radiation beam lines. Furthermore, for convenience of explanation, a case in which there is one synchrotron radiation beam line is shown here. (6) is an exposure section for performing fine phosphorography of semiconductors at I/% using the synchrotron radiation beam line (5);
In the exposure section (6), a mask (7) and a wafer (8) whose surface is coated with resist are arranged in close contact with or close to each other. (9) is a focusing quadrupole electromagnet for preventing charged particles from dispersing. α [represents a vacuum donut, which is a path for charged particles. The cavity is a high-frequency cavity that compensates for the energy loss of particles due to radiation from the synchrotron beam line and accelerates or maintains them at a predetermined energy level. In this figure, other equipment 1 such as a vacuum evacuation device and various electromagnets for beam control vM adjustment are omitted.

The next operation will be explained. First, the entrance part (2)
The charged particles incident from It continues to rotate for a long time and the charged particles are deflected! When deflected by the magnetic field of the magnet (3), electromagnetic waves are emitted in the tangential direction of the orbit due to bremsstrahlung radiation (radiation is synchrotron radiation). The spatial distribution of the synchrotron radiation beam lines is shown in the schematic diagram of FIG. As shown in Figure 3, the vertical spread of the synchrotron radiation beam with respect to the orbital plane (5) is
It is shown in the Haboshita style.

δ(radian'w 2/r (7-1/
1-β2. β=v/c) Here, V is the velocity of the particle, C
is the speed of light.

In the 9-phase position, we use high-velocity particles of V(!). Therefore, 11
By substituting typical parameters for use in sockeye into the above equation, the value of γ is in the range of 1,000 to 2β00. That is, the vertical spread of the synchrotron radiation beam is 1 to 2
(m radian). Therefore, it can be said that the synchrotron radiation beam generated from the conventional charged particle device is sufficiently wide in the horizontal direction on the orbital surface, but extremely narrow in the vertical direction. Note that the lateral spread is limited only by the width of the synchrotron radiation beam line (5) in FIG. 3; if the width is widened, the usable lateral width of the synchrotron radiation can be freely selected.

[The gap that the invention attempts to solve]

Now, one of the major problems when applying the synchrotron radiation to a semiconductor phosphor beam is that the direct irradiation area in the vertical direction is extremely narrow. Several methods have been proposed to solve this problem. Figure 7 was published by Mr. Otori in the magazine ``Applied Physics'' under the title ``1 Synchrotron Radiation Lithography''.
It is a schematic diagram regarding the conventional technique of expanding the irradiation area in the vertical direction introduced in Vol. 53, No. M1 (1984, pp 17-25). In Figure 7, α is the synchrotron radiation beam line (5)
This is a swingable total reflection mirror installed on the upstream side. This allows the synchrotron radiation beam line to be swung vertically to expand the irradiation area onto the wafer. This method has two major problems: the control mechanism for swinging the total reflection mirror α with extremely high precision in the vacuum synchrotron beam line is complicated, and the total reflection mirror is damaged by the synchrotron radiation beam. There was a problem. Furthermore, optimization of the optical properties such as reflection, absorption, and transmission of the material of the total reflection mirror (13) is also a technical issue.In addition, the essential disadvantage of the conventional method of reflecting the radiation beam with a reflection mirror is If the parallelism of the light beam is lost, it will be reduced by 1/1.One of the major advantages of using a synchrotron radiation beam line as a light source when applying a semiconductor 11 nm graph is that the synchrotron radiation beam has a high In the method shown in Figure 7, the reflection *
This is equivalent to generating a synchrotron radiation beam line in the vertical direction centering on CtS, and the width of its vibration is extremely limited from the viewpoint of parallelism.

FIG. 8 is a schematic diagram showing another conventionally known longitudinal irradiation area expansion method. this is.

The equilibrium trajectory (4) of the charged particle is defined as (b1 part l) in the storage ring.
The transverse magnetic field generating electromagnet installed in this
The beam is swung vertically using the section as a node, and the emitted light beam generated thereby is swung vertically. In this method, it is possible to oscillate the synchrotron radiation beam line by one angle in the vertical direction while maintaining parallelism, but the fluctuation width of this equilibrium trajectory is limited due to the instability of the synchrotron radiation beam. The drawback was that it could not be made larger.

Another essential problem is that only synchrotron radiation beams with different swing widths can be obtained from a plurality of synchrotron radiation beam lines. Furthermore, another disadvantage is that the beam control of charged particles itself is extremely complicated and is difficult to predict theoretically.

As an enlargement method other than heating, the exposure area (6
) Mask (7) and wafer coated with resist (8)
A possible method is to move the two together in the vertical direction without changing their relative positional relationship. In other words, without changing the irradiation area by the synchrotron radiation beam line from the charged particle device,
This method considers large-area exposure on the sample side. However, it has been pointed out that this method causes problems when using the divided exposure method. In other words, it is necessary to take enough direct product without moving the sample during one step of exposure, so this method of moving the sample cannot perform divided exposure. Line width is 0.
The target is 1 micron class, and even the slightest error in the relative positional relationship when moving the mask and wafer together cannot be tolerated. Therefore, the mechanism for moving the mask and sample wafer together becomes extremely complicated.

Note that even if the divided exposure method is not used, the mask (7)
The mechanism for moving the wafer (8) and the wafer (8) as one unit without allowing a slight relative deviation (for example, about 0.01 micron, which is 1/10 of the line width to be exposed) is extremely complicated. There are also problems with reliability.

[Means for solving problems]

The charged particle device according to the present invention moves the equilibrium trajectory of the charged particles up and down in parallel F.

The irradiation range in the vertical direction of the generated synchrotron radiation beam line is expanded, making it possible to irradiate a large area. In other words, f moves the equilibrium trajectory of the charged particle vertically and parallelly.
This is configured so that the storage ring can be moved in parallel f and in the vertical direction.

(Function) The charged particle device of this invention has a storage ring parallel to I
Since it is movable in the vertical direction, the irradiation area of the synchrotron radiation beam line can be expanded without impairing the characteristics of the synchrotron radiation beam. In other words, since the storage ring is configured to repeatedly move parallel to the vertical direction while the synchrotron radiation beam line is being generated, the irradiation area in the vertical direction of the synchrotron radiation beam line, that is, the exposure area, is larger than that of conventional systems. , it is possible to expand from several times to several tens of times, and this is possible without making the synchrotron radiation beam line, storage ring, or exposure section complicated.

Further, the advantage of parallelism of the synchrotron radiation can be fully utilized.

[Embodiments of the invention]

Hereinafter, an apparatus according to an embodiment of the present invention will be explained using the front view of FIG. (1) is the mount that fixes the storage ring (1), (1) is the movable mechanism represented by a hydraulic cylinder that moves the 3 in the vertical direction (4), and 9 is the floor on which this charged particle device is installed. , αe is a vacuum bellows inserted in a part of the synchrotron radiation beam line (5).

I'll explain the next step f. First, after accumulating a predetermined amount of charged particles in the storage ring (1), the movable mechanism α
The storage ring is moved up and down according to an operating curve preset by Xun. Here, the movement of the storage ring (1) in the vertical direction is to take advantage of the parallelism of the synchrotron radiation beam line. And said movement is a bending electromagnet (3) which is a component of the storage ring (1).

It is necessary to move the quadrupole electromagnet (9) and the other orbital electromagnets in parallel without changing their relative positions to each other. For this reason, it is easiest to fix the storage ring (1) on a common pedestal (t3) and to vibrate this pedestal (13) vertically by hydraulic control, as shown in Fig. 1. Furthermore, the vibration of the gantry α is not limited to hydraulic control, and it is clear that air or a mechanical movable mechanism may be used.

Although a system using a plurality of hydraulic cylinders has been shown, a single hydraulic cylinder may be used.

Figure ac2 is a waveform diagram showing the movement position of the storage ring in the vertical direction. It should be noted that the essence of the present invention remains the same even if the movement is performed smoothly as shown in Figure 2 (-) or in a stepwise manner like a seagull (Fig. 2). The effects of the present invention can be further enhanced by making the amount of movement, speed of movement, number of repetitions, etc. of the movement in the vertical direction programmable according to the conditions on the exposure side.

Roughly, this operation waveform is not only set in advance, but also the light intensity of the emitted light beam is monitored.

A control system is provided to control the moving speed of the storage ring (1) in the vertical direction or the number of repetitions thereof so that the time-integrated value of the amount of irradiated light is always constant at different positions on the wafer based on the monitor signal. It is also possible.

Figure 3 is a waveform diagram showing the pattern of change in the set moving speed of the control system f as described above.
In the case of +, the light amount per unit of the emitted light beam corresponds to a state in which the amount of light per unit of the emitted light beam is reduced to about 1 A compared to the case in FIG.

This shows that the amount of charged beam in the storage ring (1) typically decreases with time. Note that the amount of light per unit time of the synchrotron radiation beam is proportional to the amount of the charged beam.Even in this state, the exposure depth of the pattern transferred to the wafer (8) is determined by the irradiation time and unit of the synchrotron radiation beam. It is determined by the product of the amount of light per hour (strictly speaking, the integral value of time), so in order to obtain a constant pattern depth, it is necessary to increase the number of repetitions of the synchrotron radiation in the vertical direction (for a constant moving speed). , or it is necessary to lengthen the time for one repetition (in the case of a constant number of edges). FIG. 3 (81) is an example in which this is compensated for by slowing down the moving speed.

The present invention has the advantage that uniform exposure can be obtained since the above-mentioned limitations can be easily achieved.

Note that there are methods to monitor the amount of synchrotron radiation, such as ones that directly photoelectrically convert the synchrotron radiation, but as explained above, it can be substituted by monitoring the amount of charged beam during storage IJ7, that is, the beam intensity. It is clear inside. Next, the principle that when the storage ring is moved up and down, the synchrotron radiation beam line also moves up and down accordingly will be explained. First, the equilibrium orbit of an accelerator that accelerates and accumulates general t-particles to high energies and betatron oscillations will be briefly explained. Here, the equilibrium orbit is
A closed orbit through which the center of a charged particle or a group of charged particles passes. The actual charged particles revolve around this equilibrium orbit within the storage ring, that is, within the high-vacuum donut holder, while moving slightly. This slight vibration is called betatron vibration. These equilibrium orbits and betatron oscillations are both uniquely determined by the arrangement e of the electromagnets forming the storage ring. In other words, if the position of the electromagnet is slightly changed, the equilibrium trajectory will shift to a corresponding position. Of course, if you move the electromagnets one by one, the closed orbit itself will no longer exist, or the beam will become unstable and be lost, so make sure that the mutual positional relationship of the electromagnets is sufficient. After consideration at the design stage, the installation is usually fixed to the floor with as little tolerance as possible.

Now, in the present invention, since the electromagnet group as a whole moves up and down without changing the mutual positional relationship, the shape of the equilibrium trajectory remains the same, and its position in the height direction simply rubs up and down. On the other hand, the charged particle beam, which had been orbiting in its original equilibrium orbit beforehand, moves to a new equilibrium orbit due to the shift F of the equilibrium orbit (This movement of charged particles (beam) is microscopically explained by the following mechanism. Membranes are heard.

Now, the new equilibrium orbit of the charged particle is [
Suppose that 18fi is moved for a short time. Here, the original trajectory l
The scattered charged particles start betatron oscillations with an initial amplitude value of (city attack), but this betatron oscillation is a vertical oscillation.It should be noted that this oscillation emits a synchrotron radiation beam line1. Extremely short time due to radiation braking
This attenuates. The time constant of this decay is usually several milliseconds in a storage ring used for synchrotron radiation, and if we look at this in a macroscopic way, even if we consider that the charged particles instantly shift to a new equilibrium orbit, there is no problem with the total (1) /1° Therefore, since the synchrotron radiation beam line is generated from the charged particle position, the synchrotron radiation beam line also moves in the vertical direction. However, in a few milliseconds, it moves a large distance that can exceed the gap distance of the magnet. If the particle is moved faster than the amplitude attenuates (a situation will occur where the particle hits the magnetic pole of the magnet), the movement speed should not be such an ultra-high speed.Of course, the movement of the storage ring in the present invention is as follows. There is no need to do it at such an ultra-high speed, so there is no problem at all.The vacuum bellows αQ shown in Figure 1 is
This is used to absorb vertical displacement of the storage ring (1).

In Figure 1, the upstream side of the charged particle injection section (2) is omitted, but if a similar vacuum bead is also placed in a part of this injection line, the injector (not shown in the figure) can be replaced. Similar to the case of the synchrotron radiation beam line (5), it is possible to absorb the displacement in height.

FIG. 4 is a front view of a device according to another embodiment of the invention, in this case the deflection electromagnet (3) of the storage ring (1).
consists of a superconducting electromagnet. This superconducting electromagnet has features such as being able to increase the strength of the magnetic field, increasing the amount of emitted light, and making the entire storage ring smaller and lighter. Furthermore, as other embodiments, it is of course possible to use a weakly converging electromagnet and apply the present invention to a small storage ring.

In addition, in the above embodiment, the vacuum donut α1 is also an electromagnet (
3), etc. However, as described in the operating principle above, even if only the electromagnet group is moved uniformly in the vertical direction, the effect will not change at all.

〔Effect of the invention〕

As described above, according to the practical example of the present invention, one storage ring (1) is configured to move in parallel in the vertical direction with respect to one floor haze, so it is inexpensive and has a simple configuration. It has the effect of being able to irradiate a large area with high performance and unprecedented performance.

[Brief explanation of drawings]

Fig. 1 is a front view showing a charged particle device according to an embodiment of the present invention, Fig. 2 (AL (Bl) and Fig. 3 (At, fB
1 is an operational characteristic diagram of the present invention, and FIG. 4 is a front view 1M showing a charged particle device according to another embodiment of the present invention.
Figure 5 is a straight view showing a conventional charged particle device, Figure 3 is a schematic diagram showing the spatial distribution of a conventional synchrotron radiation beam line, and Figures 7 and 8 each show a conventional synchrotron radiation beam line expansion method. FIG. In the figure, (1) is a storage ring, (2) is an entrance part, (3) is a bending magnet, (4) is an equilibrium orbit, (5) is a synchrotron radiation beam line, (6) is an exposure part, and (7) is a synchrotron radiation beam line. is a mask, (8) is a wave, (9) is a quadrupole electromagnet, and 0 is a vacuum donut.
(11) is a high frequency cavity. α is a reflecting mirror, (131 is a stand, α■ is a movable mechanism, (formerly is a floor, (lI19 is a vacuum bellows. The same reference numerals in each figure indicate the same or equivalent parts. Agent: Patent Attorney S. Masaru Fuji Year Δ・H?487 Fig. 8 鐸 l provision (cm) tIf movement - f (cm) 5th rs 4-H9417 Fig. 6

Claims (10)

[Claims] (1) In a charged particle device that generates and uses a synchrotron radiation beam, the vertical irradiation range of the generated synchrotron beam line can be expanded and maintained by vertically moving the equilibrium trajectory of the charged particles in parallel. A charged particle device that is characterized by being able to irradiate a large area. (2) A charged particle device according to claim 1, characterized in that a storage ring consisting of a plurality of electromagnets and vacuum donuts is movable vertically in parallel together with a common pedestal. (3) In a storage ring consisting of multiple electromagnets and vacuum donuts, the multiple electromagnets move in parallel in the vertical direction while keeping their relative positional relationship constant. 2. The charged particle device according to claim 1, wherein the charged particle device is capable of being used. (4) The charged particle device according to claim 2 or 3, wherein the vertical movement is performed by hydraulic or pneumatic control. (5) The upstream side of the synchrotron radiation beam line moves vertically along the balanced trajectory, the downstream side is fixed at a constant height relative to the floor, and the upstream and downstream sides are flexibly connected by a vacuum bellows. A charged particle device according to claim 1, characterized in that: (6) The charged particle device according to claim 1, wherein the storage ring includes a bending electromagnet made of a superconducting electromagnet. (7) The charged particle device according to claims 2 and 3, characterized in that the amount of movement in the vertical direction, the speed of movement, and the number of repetitions are programmable. (8) A control system is provided for controlling the vertical movement speed and/or the number of repetitions so that the time integral value of the amount of light irradiated is always constant based on the signal from the synchrotron radiation monitor. Charged particle device according to claims 2 and 3. (9) The charged particle device according to claim 8, characterized in that a charged beam intensity monitor of a storage ring is used as a radiation light intensity monitor. (10) Downstream side of charged particle incident line (storage ring side)
moves vertically along the balanced trajectory, the upstream side (injector side) is fixed at a constant height relative to the floor, and the upstream and downstream sides are flexibly connected by a vacuum bellows. A charged particle device according to claim 1.