JPH11160499A - Laser plasma x-ray generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser plasma X-ray generation device capable of highly precisely performing X-ray scanning on a sample in simple constitution. SOLUTION: In a laser plasma X-ray generation device irradiating a target with a laser beam and generating an X-ray by a laser plasma method, an optical system (converging lens 4) shifting an irradiation position 21 of the laser beam on the target 5 is provided. The irradiation position 21 of the laser beam on the target 5 is shifted by the optical system 4, and an X-ray irradiation position 22 on a sample 7 is shifted to scan the X-ray on the sample 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an X-ray source laser,
The present invention relates to a laser-plasma X-ray generator used for an X-ray source such as a source lithography apparatus, an X-ray exposure apparatus, an X-ray source microscope, an X-ray source electron microscope, and an X-ray source analyzer.

[0002]

2. Description of the Related Art In an X-ray source laser, an X-ray source lithography apparatus, an X-ray exposure apparatus, an X-ray source microscope, an X-ray source electron microscope, an X-ray source analyzer, etc. Using lines. As this X-ray generator, an X-ray tube and a plasma X-ray source are known. The plasma X-ray source uses X-rays generated by the interaction between highly ionized multiply-charged ions and electrons formed in the plasma, and a laser plasma X-ray generator that generates high-density plasma by laser light is known. ing. In a laser plasma X-ray generator, 10 μm
m, the laser light focused on Al, Mo,
It is formed by condensing and irradiating a metal surface such as W, Ta, Au or the like with pulses at intervals of several ns.

FIG. 6 is a schematic diagram for explaining the configuration of a conventional laser plasma X-ray generator. In FIG. 6, a conventional laser plasma X-ray generator guides a laser beam emitted from a laser source 11 to a laser focusing lens 14 via a collimator 12 and a mirror 13 and collects the laser beam on a target 15. Light up. On the target 15, plasma is generated by the laser light, and X-rays are emitted. The emitted X-rays
The X-ray is focused on the sample 17 by the optical member 16 for focusing.

[0004] The mirror 13 is fixed at an angle adjusted so that the laser beam is directed to the target 15. The target 15, the X-ray focusing member 16, and the sample 17 are housed in a vacuum vessel 18.

[0005]

A conventional laser plasma X-ray generator as shown in FIG. 6 usually focuses and irradiates X-rays on one point on a sample, and performs analysis and processing at one point. Is what you do. Therefore, there is a problem that two-dimensional analysis and processing cannot be performed on the sample. In order to perform two-dimensional analysis and processing on a sample, it is necessary to scan X-rays on the sample.

In the laser plasma X-ray generator having the conventional configuration, in order to scan an X-ray on a sample, a configuration in which a laser source or a laser focusing element is scanned, a configuration in which an X-ray focusing member is finely moved, A configuration for scanning the sample is conceivable. However, in such a configuration, it is necessary to move the laser source, the X-ray focusing member, the sample stage, and the like, and there is a problem that the scanning mechanism becomes large, and the size and mass of the moving body are large. However, there is a problem that it is difficult to obtain high movement accuracy, and the position accuracy of the X-ray focal point on the sample is insufficient.

Therefore, the present invention solves the above-mentioned problems of the conventional laser plasma X-ray generator and provides an X-ray image on a sample.
An object of the present invention is to provide a laser plasma X-ray generator capable of performing line scanning with high accuracy with a simple configuration.

[0008]

According to the laser plasma X-ray generator of the present invention, the position of X-rays on a sample is changed by changing the condensing position of laser light condensed on a target. , X-ray scanning.

A laser plasma X-ray generator according to the present invention is a laser plasma X-ray generator for irradiating a target with laser light to generate X-rays by a laser plasma method. An optical system for shifting the irradiation position of the laser light is provided, and by this optical system, the irradiation position of the laser light on the target is shifted, the X-ray irradiation position on the sample is shifted, and the X-ray is scanned on the sample. Configuration.

[0010] The optical system provided between the target and the laser source has a function of directing the laser light emitted from the laser source toward the target and, in the present invention, a function of shifting the focal position of the laser light on the target. Have Then, by shifting the focus position of the laser beam on the target, the position where the X-ray emitted from the focus position is focused on the sample is shifted, and the X-ray is scanned on the sample. At this time, by controlling the optical system using the relationship between the control of the optical system and the movement of the X-ray on the sample, the irradiation position of the X-ray on the sample can be arbitrarily determined.

In a first embodiment of the laser plasma X-ray generator according to the present invention, the optical system is a reflecting member which is rotatable with respect to the optical axis of the incident laser light. The focusing position of the laser light above can be shifted.

[0012] The rotation axis of the reflecting member may be provided with two axes having an angle with respect to the optical axis, whereby the condensing position of the laser beam on the target can be shifted in two dimensions. it can.

In a second embodiment of the laser plasma X-ray generator according to the present invention, the optical system is a reflecting member which can move in parallel with respect to the optical axis of the incident laser light. In addition, the focal position of the laser beam on the target can be shifted.

The parallel movement axis of the reflecting member can be configured to have two axes having angles other than parallel, and thereby the laser light condensing position on the target can be shifted in two dimensions. .

In a third embodiment of the laser plasma X-ray generator according to the present invention, the optical system is a reflecting member which is rotatable and parallel movable with respect to the optical axis of the incident laser light. By rotating and translating, the focusing position of the laser light on the target can be shifted, and the position of the focusing system provided between the target and the target can be adjusted to correct the aberration of the focusing system. it can.

A fourth embodiment of the laser plasma X-ray generator according to the present invention is directed to a relationship between the control amount by the optical system and the amount of X-ray movement on the sample, and / or the control position by the optical system and the position on the sample. The X-ray irradiation position on the sample can be arbitrarily set by controlling the optical system.

In a fifth embodiment of the laser plasma X-ray generator according to the present invention, a condensing member for condensing X-rays one by one at the same magnification or reduction magnification between a target position and a sample position is provided. To provide
Scanning can be performed by associating the X-ray condensing position on the sample with the condensing position of the laser light that changes on the target one-to-one.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. A configuration example of an embodiment of the present invention will be described with reference to the outlines of FIGS. 1 to 5 illustrating the embodiment of the laser plasma X-ray generator of the present invention. 1 and 2 are schematic diagrams illustrating the first embodiment, FIGS. 3 and 4 are schematic diagrams illustrating the second embodiment, and FIG. 5 is a diagram illustrating the third embodiment. FIG.

First, a first embodiment will be described. In FIG. 1, a laser beam emitted from a laser source 1 is made coherent by a collimator 2 and is incident on a laser focal point 20 on a movable mirror 3. The movable mirror 3 constitutes an optical system that shifts the irradiation position of the laser beam on the target in order to shift the X-ray irradiation position on the sample and scan the sample with X-rays. Is rotatable by a rotation axis having an angle with respect to the optical axis. In FIG. 1, the rotation axis has two orthogonal axes, an X-axis and a Y-axis, so that the angle with respect to the laser beam can be arbitrarily changed. The rotation axis can be rotated in an arbitrary rotation direction and rotation amount by a driving mechanism (not shown), and the irradiation position of the reflected laser light on the target 5 can be arbitrarily shifted.

The laser light reflected by the movable mirror 3 is
Target 5 through condensing lens 4 for condensing laser
The light is focused on the upper laser focusing point 21. The laser light focused on the target 5 generates plasma and emits X-rays. The laser focal point 21 can be shifted by controlling the position of the rotation axis of the movable mirror 3.

The target 5 is formed in a ribbon tape shape.
Between the target winding section 8 and the second target winding section 9, the target can be moved in the longitudinal direction by rewinding one of them and winding the other by a driving device (not shown). Note that the movement of the target by the driving device is performed after the irradiation of the laser light, so that the small holes formed in the target 5 by the irradiation of the laser light can be shifted from the laser irradiation point to prepare for the next laser irradiation.
For example, the diameter of a small hole formed by laser beam irradiation is 100
In the case of about μm, by setting the movement amount of the target 5 to about 1 mm, the influence of the small holes on the next laser irradiation can be ignored. Further, the power supply voltage for driving the laser source 1 can be a DC voltage or a pulse voltage. When the pulse voltage causes the laser light to be pulsed light, power consumption can be reduced.

The target 5 is made of Al, Mo, W, T
a, a conductive target material such as Au, or an insulating material such as plastic can be used.

X-rays generated by the laser beam are emitted from the laser condensing point 21 on the target 5 with a predetermined scattering distribution intensity, and are condensed on the sample 7 via the X-ray condensing member 6. The point 22 is irradiated. Note that the X-rays in FIG. 1 represent a predetermined direction such as the direction of the maximum intensity among the X-ray scattering distribution intensities. The X-ray focusing member 6 can be configured by a reflecting mirror or the like, and the laser focusing point 21 on the target 5 and the X-ray focusing point 22 on the sample 7 are configured to correspond one-to-one.

Here, the relationship between the rotation angle position of the movable mirror 3 and the position of the X-ray focal point 22 on the sample 7, the amount of rotation angle of the movable mirror 3 and the position of the X-ray focal point 22 on the sample 7, The relationship with the position amount can be obtained in advance by the positional relationship between the laser source 1, the movable mirror 3, the target 5, the X-ray focusing member 6, the sample 7, the characteristics of each optical system, and the like. Since the laser converging point 21 and the X-ray converging point 22 on the sample 7 are in one-to-one correspondence, by controlling the rotational position and the amount of rotation of the movable mirror 3,
The position and the amount of movement of the line converging point 22 can be controlled.

The control of the movable mirror 3 can be performed by storing the above-described relationship and operating a drive device and a control device (not shown) using the relationship.

FIG. 2 is a view for explaining the X-ray condensing position on the sample 7 which is shifted by the rotation of the movable mirror 3. In FIG. 2, the movable mirror 3 shows three rotational positions indicated by a solid line, a broken line, and an alternate long and short dash line, and laser beams and X-rays corresponding to these rotational positions are indicated by similar line types. When the movable mirror 3 is rotated with respect to the incident laser light, the laser light reflected at the reflection point 20 is focused on a different laser focus point 21 on the target 5. Each laser focal point 21
X-rays emitted from the sample 7 are sampled by the X-ray focusing member 6.
The light is focused on the X-ray focusing point 22 corresponding to the laser focusing point 21 on a one-to-one basis.

Although FIG. 2 shows only one axis of rotation, the position of the X-ray on the sample 7 is two-dimensionally shifted by performing the same operation on the other axis that is not parallel to the axis. Scanning.

Although FIG. 1 shows a plurality of laser beams and X-rays between the movable mirror 3 and the sample 7, the laser beams and the X-rays whose reflection directions are changed by the rotation of the movable mirror 3 are shown. This is because the state of the line is shown in the same drawing.
X-rays are emitted from the laser focal point 21 with a predetermined scattering distribution intensity.

Next, a second embodiment will be described.
In the second embodiment, the influence of the aberration of the condenser lens is reduced by rotating and moving the movable mirror in parallel. In FIG. 3, a laser beam emitted from a laser source 1 is made coherent by a collimator 2 and is incident on a laser converging point 20 on a movable mirror 3 as in the first embodiment. The movable mirror 3 is configured to be rotatable about a rotation axis having an angle with respect to the optical axis of the laser beam, and to be capable of moving in parallel. In FIG. 3, the rotation axis has two orthogonal axes, an X axis and a Y axis.
The figure shows a configuration that can be moved in the direction of the axis, whereby the angle of the laser beam can be arbitrarily changed and the laser beam can be translated. The above rotation and parallel movement can be performed by a drive mechanism (not shown) in an arbitrary rotation direction, rotation amount, and movement amount. The irradiation position of the reflected laser light on the target 5 can be arbitrarily shifted by rotating and moving the movable mirror 3.

Further, by moving the movable mirror 3 in parallel, it is possible to correct the laser beam so as to pass through the center of the optical axis of the condenser lens 4, thereby reducing the deviation due to the aberration of the condenser lens 4. Can be. The laser beam reflected by the movable mirror 3 passes through a laser condensing lens 4 or the like to a laser condensing point 21 on the target 5.
When the movable mirror 3 is rotated, the laser light passes through a position deviated from the optical axis center of the condenser lens 4. In general, since the condenser lens 4 has an aberration, a laser beam passing through a position deviated from the center of the optical axis is shifted by the aberration. In contrast, FIGS.
As shown by the broken line in the middle, when the movable mirror 3 is moved in parallel, the reflection point on the movable mirror 3 moves from 20 to 20y. Thereby, the laser beam reflected at the reflection point 20y can be corrected so as to pass through the center of the optical axis of the condenser lens 4. The laser light that has passed through the center of the optical axis of the condenser lens 4 is condensed on a laser focal point 21y on the target 5, generates plasma, and emits X-rays. The laser focal point 21y can be shifted by controlling the position of the rotation axis of the movable mirror 3. Note that the configurations and operations of the target 5, the X-ray focusing member 6, and the sample 7 are substantially the same as those of the first embodiment, and thus detailed description is omitted here.

The relationship between the rotation angle position and the parallel movement position of the movable mirror 3 and the position of the X-ray focusing point 22 on the sample 7, the rotation angle amount and the parallel movement amount of the movable mirror 3 and the sample 7
The relationship between the position of the X-ray focusing point 22 and the position amount of the X-ray focusing point 22 can be obtained in advance based on the positional relationship between the laser source 1, the movable mirror 3, the target 5, the X-ray focusing member 6, the sample 7, the characteristics of each optical system, and the like. In addition, since the laser converging point 21 on the target 5 and the X-ray converging point 22 on the sample 7 correspond one-to-one, the rotation position, the rotation amount, and the parallel position amount of the movable mirror 3 are determined. , The position and the amount of movement of the X-ray focal point 22 on the sample 7 can be controlled. Although FIGS. 3 and 4 show the parallel movement only in the Y-axis direction, the parallel movement can be constituted by the X-axis direction or a plurality of non-parallel axes.

FIG. 4 is a view for explaining the focus position of X-rays on the sample 7 which is changed by the parallel movement of the movable mirror 3. In FIG. 4, the movable mirror 3 shows two positions indicated by a solid line and a broken line.
The lines are shown with a similar line type. When the movable mirror 3 is rotated and translated with respect to the incident laser light, the reflection point 20
The laser light reflected by y passes through the center of the optical axis of the condenser lens 4 and is then focused on a different laser focus point 21y on the target 5. The X-rays emitted from the respective laser focus points 21 and 21y are converted by the X-ray focus member 6 into the X-ray focus points 22 corresponding to the laser focus points 21 on the sample 7 on a one-to-one basis.
Focus on

Next, a third embodiment will be described.
The third embodiment is a configuration example in which X-rays reduced by an X-ray focusing member are focused on a sample. The configuration of the third embodiment shown in FIG. 5 can be the same as the configuration of the first or second embodiment except for the configuration of the X-ray focusing member. Only the configuration of the members will be described.

X-ray focusing members 6a and 6b according to the third embodiment
Reduce the X-rays emitted from the target 5
It is an optical member that condenses light on the upper side, and can be configured by arranging curved reflecting members orthogonally.
By the X-ray focusing members 6a and 6b, the length of Lx on the target 5 is reduced to 1x on the sample 7, the length of Ly is reduced to ly on the sample 7, and the area S is reduced to s. Scaled down. Thereby, the scanning accuracy on the sample 7 can be improved. It should be noted that the X-ray focusing member for reducing the X-rays is not limited to the above-described configuration, and may have another configuration.

[0035]

As described above, according to the laser plasma X-ray generator of the present invention, X-ray scanning on a sample can be performed with high accuracy with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a first embodiment.

FIG. 2 is a schematic diagram illustrating a first embodiment.

FIG. 3 is a schematic diagram illustrating a second embodiment.

FIG. 4 is a schematic diagram illustrating a second embodiment.

FIG. 5 is a schematic diagram illustrating a third embodiment.

FIG. 6 is a schematic diagram for explaining a configuration of a conventional laser plasma X-ray generator.

[Explanation of symbols]

1 laser source, 2 collimator, 3 movable mirror, 4
... Condenser lens, 5 ... Target, 6 ... X-ray condenser member, 7
... Sample, 8, 9 ... Target winding part, 20 ... Reflection point, 2
1: laser focus point, 22: X-ray focus point.

Claims (1)

[Claims] 1. A laser plasma X-ray generator for irradiating a target with laser light to generate X-rays by a laser plasma method, wherein an irradiation position of the laser light on the target is shifted between the target and a laser light source. An optical system, wherein the optical system shifts an X-ray irradiation position on a sample by shifting an irradiation position of a laser beam on a target, and scans the sample with X-rays. Line generator.