JPH03182040A - Irradiation device for neutral particle beam - Google Patents

Abstract

PURPOSE:To eliminate deflection for an ion beam orbit, by providing a making- neutral-particle means for changing an ion beam into neutrons on the passage exit of the selected ion beam. CONSTITUTION:An ion beam 3, including many ions outputted from an ion source 2 such as a liquid metal ion source or plasma ion source, is given to a mass spectrograph 13. A stable H<+> beam 3A selected with no analyzer 13 passes through a deflecting system 9, goes through a gas atmosphere generated from a neutral gas generation device 10, e.g. a H2 gas atmosphere, and a load exchange reaction is made to produce a neutral beam H. The neutral particle beam H is irradiated to a substrate 10. Consequently the electrification of the substrate 10 is eliminated, and even the substrate 10 is previously electrified, the deflection for the beam due to an electrified electric charge can be avoided to finely irradiate the beam to the substrate 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a neutral particle beam irradiation device for irradiating a sample surface with a focused neutral particle beam.

[Conventional technology]

2. Description of the Related Art As semiconductor devices become more highly integrated, circuit patterns are required to become finer. In the resist pattern forming process, the impurity implantation process, and the sample surface processing process included in the circuit pattern fEJ fabrication process, a focused ion beam is applied to the sample in order to achieve finer circuit patterns. A device that irradiates the area is used.

FIG. 4 is a schematic diagram of an ion beam irradiation device for irradiating a sample with a focused ion beam.

Reference numeral 1 denotes an ion beam column, which houses the following components. An ion beam 3 containing various types of ions generated from an ion source 2 is focused by an electrostatic lens 5 . The ion source 2 uses a liquid metal ion source, which is a high-brightness ion source that is advantageous for beam focusing. Mass spectrometer 13
forms a region to which magnetic and electric fields are applied. When the ion beam 3 passes through this region, only the ion beam corresponding to the strength of the magnetic field and electric field travels straight, and the trajectory of the other ion beams is bent. In this way, a desired ion beam is selected by the mass spectrometer 13. The trajectory of the selected ion beam 3 is corrected by a blanking coil 6 and selectively passed through a beam forming slit 7. Ion beam 3 passing through beam forming slit 7
is focused by an electrostatic lens 8 and deflected by an electrostatic deflector 9, and the substrate 1 is placed on a movable stage 11.
0 desired location is irradiated. Ion source 2 as described above
If a liquid metal ion source is used for this purpose, a diameter of 0.5 mm will be formed on the substrate 10.
The ion beam 3 can be focused to about 1 μm,
By applying an appropriate deflection signal to the deflector 9, the ion beam 3 can be irradiated onto a desired location on the substrate 10 with high precision.

[Problem to be solved by the invention]

However, depending on the type of semiconductor manufacturing process, the surface of the substrate 10 may already be charged by the ion beam irradiated onto the substrate 10.

In this case, the charges on the substrate surface and the charges on the ion beam 3 repel each other, and the trajectory of the ion beam 3 is deflected.
There was a problem in that the ion beam 3 could not be accurately irradiated to a desired position on the substrate 10, and the accumulated electric charges had to be removed.

This invention was made to solve the above-mentioned problems, and the surface of the substrate is not charged even when the beam is irradiated.
Another object of the present invention is to provide a neutral particle beam irradiation device in which the trajectory of the beam is not deflected even if the substrate surface is charged.

[Means to solve the problem]

A neutral particle beam irradiation device according to claim 1 includes: an ion source that generates a stable ion beam; and a lens that is provided on the path of the ion beam generated from the ion source and that focuses the ion beam. , ion beam selection means provided on the path of the ion beam to select only a desired ion beam from among the ion beams, and deflection means provided on the path of the ion beam to change the direction of the ion beam. , a neutral particle converting means provided at a path exit of the ion beam for converting the ion beam into neutral particles.

A neutral particle beam irradiation device according to a second aspect of the present invention includes: an ion source that generates a stable ion beam; and a lens that is provided on the path of the ion beam generated from the ion source and that focuses the ion beam. , ion beam selection means provided on the path of the ion beam to select only a desired ion beam from among the ion beams, and deflection means provided on the path of the ion beam to change the direction of the ion beam. , a charge exchange means provided on the path of the ion beam and for reversing the charge state of the beam; and a charge exchange means provided at the exit of the ion beam path and having its charge state reversed by the charge exchange means. and a neutral particle forming means for converting the particles into neutral particles.

A neutral particle beam irradiation device according to a third aspect of the present invention includes an ion source that generates an unstable ion beam, and a lens that is provided on a path of the ion beam generated from the ion source and that focuses the ion beam. ion beam selection means provided on the path of the ion beam to select only a desired ion beam from among the ion beams; and deflection means provided on the path of the ion beam to change the direction of the ion beam. and a neutral particle converting means provided at a path exit of the ion beam for converting the ion beam into neutral particles.

[Effect]

In this invention, a neutral particle converting means for converting the ion beam into neutral particles is provided at the exit of the ion beam path,
Since the beam irradiated onto the sample is made into neutral particles, the sample will not become electrically charged, and even if the material is electrically charged, the trajectory of the beam will not be deflected.

〔Example〕

FIG. 1 is a schematic diagram showing a first embodiment of a neutral particle beam irradiation device according to the present invention. liquid metal ion source,
An ion beam 3 containing various types of ions outputted from an ion source 2 such as a plasma ion source passes through a path similar to the conventional one and is applied to a mass spectrometer 13. The mass spectrometer 13 selects stable positive ions, such as H. This selected I
(The beam 3A goes through the same process as the conventional one, and finally passes through a gas atmosphere, for example, a hydrogen H2 gas atmosphere, generated from the neutral gas generator 100 as a means for generating neutral particles, and undergoes charge exchange as described below. A reaction takes place and a neutral beam H is created.

B+ (beam)+H→old beam) 10 H2+This neutral particle beam H is irradiated onto the substrate 10.

Therefore, the substrate 10 is not charged, and even if the substrate is previously charged, the beam is not deflected by the charged charges, and the beam can be irradiated onto the substrate 10 very finely.

In the above example, stable positive iono-H was used to form neutral particles, but it is also possible to use stable negative ions to form neutral particles in the same manner as described above.

FIG. 2 shows the second part of the neutral particle beam irradiation device according to the present invention.
FIG. 1 is a schematic configuration diagram showing an example. The ion source 2 uses a conventionally used liquid metal ion source, and generates an ion beam 3a containing stable positive ions at an accelerating voltage of, for example, 30 kV. The positive ions contained in the ion beam 3a are converted into the ion beam 3b containing negative ions by using the charge exchanger 4. For example, when the ion beam 3a emitted from the ion source 2 contains stable boron ions (B+), the charge exchanger 4 evaporates magnesium.
This creates magnesium vapor in the orbit of the ion beam. When boron ions B+ pass through this magnesium vapor, since magnesium has a lower ionization energy than boron, a charge exchange reaction expressed by the following equation occurs, and negative boron ions B 2 are generated.

The ion beam 3b containing negative ions (B-) passes through the electrostatic lens 5.
After being focused by a lens system comprising: The mass spectrometer 13 selects only negative boron ions B from the ion beam 3b. The trajectory of the negative boron ions B is bent by the blanking coil 6. For example, during drawing, negative boron ions B are generated by the blanking coil 6 so that they pass through the opening of the beam-shaped slit 7, and when blocking, they are irradiated to a location other than the opening of the beam-forming slit 7 and are blocked. Adjust the electric field. The negative boron ions B that have passed through the beam forming slit 7 are focused by an electrostatic lens 8 and then deflected by a deflector 9.

By the way, the electrons of the negative boron ions B converted by the charge converter 4 are bound to the atoms by a relatively weak force, so if energy is given to the atoms by, for example, irradiation with light, they can be efficiently transferred to the atoms. It is known that the ions become neutral particles when the ions and electrons separate. Therefore, when the polarized ion beam 3b is irradiated with light having a wavelength of 8,000, for example, from the laser device 200, the negative ion beam 3b is converted into neutral particles. This neutralized ion beam 3b is irradiated onto a desired location on the substrate 10.

Therefore, the same effects as in the above embodiment can be obtained.

Note that the charge exchanger 4 may be installed at any position upstream of the laser device 200, and is not limited to the position shown in FIG. 2.

In the above embodiment, the charge exchanger 4 was shown to produce magnesium vapor on the ion beam trajectory, but positive boron ions B It is also possible to adopt a configuration in which the light is incident. In this case, as is well known, when positive boron ions B are reflected from the tungsten surface, they become negative boron ions B. Further, metals other than tungsten W may be used.

FIG. 3 shows the third part of the neutral particle beam irradiation device according to the present invention.
FIG. 1 is a schematic configuration diagram showing an example. The difference between this embodiment and the embodiment shown in FIG. The advantage is that a laser device 200 is provided instead of the gas generating device 100. The rest of the structure is the same as the embodiment shown in FIG.

The ion source 300 generates unstable negative hydrogen ions H by ionizing hydrogen H2 using, for example, a well-known plasma ion source. Hydrogen ion H is boron ion B
Similarly, since electrons are bound to atoms by a relatively weak force, the atoms and electrons are separated by the light irradiated from the laser device 200, and the hydrogen ions H become neutral particles H. Even with such a configuration, the same effects as in the above embodiment can be obtained.

In the above embodiment, a case has been described in which hydrogen ions H- are generated using a plasma ion source, but unstable negative ions can also be generated by ionizing other gases.

Furthermore, when unstable positive ions are generated, it is necessary to replace the laser device with an electron supply device. in this case,
Since unstable positive ions are considered to be in a state where they are likely to take in electrons, the same effects as in the above example can be obtained even with such a configuration in which it is thought that they are easily neutralized when electrons are supplied. .

〔Effect of the invention〕

As described above, according to the present invention, a neutral particle converting means for converting the ion beam into neutral particles is provided at the exit of the ion beam path, and the beam irradiated onto the sample is converted into neutral particles. The sample is not electrically charged, and even if the sample is pre-charged, the beam is not deflected, and the beam can be irradiated accurately and minutely.

[Brief explanation of drawings]

1 to 3 are schematic configuration diagrams showing one embodiment of a neutral particle beam irradiation device according to the present invention, and FIG. 4 is a schematic configuration diagram of a conventional ion beam irradiation device. In the figure, 2 and 300 are ion sources, 3 and 3a are ion beams, 4 is a charge exchanger, 5 and 8 are electrostatic lenses,
9 is a deflector, 13 is a mass spectrometer, 100 is a neutral gas generator, and 200 is a laser device. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (3)

[Claims] (1) An ion source that generates a stable ion beam, a lens provided on the path of the ion beam generated from the ion source and for focusing the ion beam, and a lens provided on the path of the ion beam. , ion beam selection means for selecting only a desired ion beam from among the ion beams; deflection means provided on the path of the ion beam to change the direction of the ion beam; and deflection means provided at the exit of the path of the ion beam. A neutral particle beam irradiation device comprising: , a neutral particle converting means for converting the ion beam into neutral particles. (2) an ion source that generates a stable ion beam; a lens provided on the path of the ion beam generated from the ion source and for focusing the ion beam; and a lens provided on the path of the ion beam. , ion beam selection means for selecting only a desired ion beam from among the ion beams; deflection means provided on the path of the ion beam to change the direction of the ion beam; and deflection means provided on the path of the ion beam. , a charge exchange means for reversing the charge state of the ion beam, and neutral particles provided at the exit of the path of the ion beam and for converting the ion beam whose charge state has been reversed by the charge exchange means into neutral particles. A neutral particle beam irradiation device equipped with a means for converting. (3) an ion source that generates an unstable ion beam; a lens provided on the path of the ion beam generated from the ion source and for focusing the ion beam; and a lens provided on the path of the ion beam. ion beam selection means for selecting only a desired ion beam from among the ion beams; deflection means provided on the path of the ion beam to change the direction of the ion beam; and deflection means provided at the exit of the path of the ion beam. A neutral particle beam irradiation device comprising: a neutral particle converting means for converting the ion beam into neutral particles.