JP3752259B2 - Cluster ion beam sputtering method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a cluster ion beam sputtering method . More specifically, the present invention relates to a cluster ion beam sputtering method using a method for selecting cluster ions having a large size required for sputtering .
[0002]
[Prior art and its problems]
Conventionally, various gas phase reaction methods have been developed for the purpose of thin film formation. As one of the methods, sputtering using a cluster ion beam irradiation method in which a cluster consisting of massive atomic groups or molecular groups is ionized by electron irradiation is practical. It has become.
[0003]
In the case of this method, it is thought that it is necessary to irradiate the workpiece with large size cluster ions. It has become an important issue for sputtering by the method.
[0004]
That is, for example, it is known that a cluster ion having a large size has a lower energy than a cluster ion having a small size even when accelerated by the same voltage, and the lateral sputtering effect at the time of substrate collision is remarkable. For this reason, it is considered that it is important to remove small cluster ions and atomic ions and to select large cluster ion beams in sputtering. Therefore, as a method for selecting the cluster size, a magnetic field method, an ExB method, a method combining flight time and pulse chop, a deceleration electric field method, and the like have been proposed.
[0005]
However, in the case of these conventional methods, the magnetic field method or ExB method requires a heavy magnet to be incorporated in the sputtering apparatus, which is not suitable because the apparatus becomes complicated, and also requires a time-of-flight method. Since the apparatus is complicated, handling is difficult, and there is a difficulty as a method for selecting the cluster size. Furthermore, the deceleration electric field method has a simple structure and it is easy to select the cluster size, but it is difficult to select a cluster ion of a specific size.
[0006]
For this reason, it is possible to easily and effectively select large-sized cluster ions required for sputtering by removing single atoms and small-sized cluster ions in a sputtering apparatus using a cluster ion beam irradiation method. Realization of an improved method has been highly desired.
[0007]
The present invention has been made in view of the above circumstances, eliminates the drawbacks of the conventional cluster ion sorting method, sorts only cluster ions of a size suitable for sputtering, and selectively covers them. The object is to provide a sputtering method for irradiating a workpiece.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention, in a cluster ion beam sputtering method using a cluster ion beam irradiation apparatus , causes chromatic aberration by an electrostatic lens to a cluster ion beam having energy corresponding to the cluster size, Provided is a cluster ion beam sputtering method characterized in that cluster ions having a specific energy are focused on an aperture portion to size-select cluster ions, and sputtering is performed using the selected cluster ions .
[0009]
[Action]
In other words, the present invention makes it possible to take out only cluster ions of a larger size and irradiate the workpiece by sputtering by using the cluster size selection method combining the electrostatic lens and the aperture as described above. Yes.
[0010]
More specifically, chromatic aberration occurs when the energy of the beam incident on the electrostatic lens is different. On the other hand, since the cluster ion beam includes clusters of different sizes, the beam has energy depending on the cluster size. For this reason, when an electric field lens is used, chromatic aberration depending on the size of cluster ions occurs. Therefore, cluster ions with different energies also have different focal positions, so if you install an aperture at the focal point and adjust the lens voltage to focus on the aperture part, that energy beam, that is, a beam with a specific cluster size Can be sorted out.
[0011]
The selection of the cluster size is particularly effective when ionizing and using a gas cluster composed of a gaseous substance at room temperature proposed by the inventors of the present invention. This is because the energy is controlled by the cluster size, and the characteristics of the gas cluster ion beam are further exhibited.
[0012]
For this gas cluster, reactive gases such as CO ₂ , N ₂ , O ₂ , their compounds, hydrocarbons, silicon compounds and the like effective for forming a sputtered thin film can be used.
[0013]
These gas clusters can be made into beams by ejecting compressed gas from a nozzle and then passing through a skimmer.
[0014]
Of course, the method of the present invention can be applied to a cluster of evaporated atoms or molecules such as metals, not limited to gas clusters.
[0015]
Hereinafter, the cluster ion beam sputtering method of the present invention will be described in more detail with reference to examples.
[0016]
【Example】
1 and 2 of the accompanying drawings are schematic views of a cluster ion beam sputtering apparatus to which the method of the present invention is applied . FIGS. 1 and 2 describe a sputtering apparatus using a gas cluster ion beam, and FIG. 2 shows a more specific apparatus configuration.
[0017]
For example, referring to FIG. 1, a simple sputtering apparatus having a cluster size selection apparatus combining an electrostatic lens and an aperture provided in a gas cluster ion beam irradiation apparatus will be described. A cluster ion beam generated from a nozzle (1) is a skimmer. Go through (2) and enter the ionization electrode system (3). The ionized ion beam is extracted by the electric field formed by the extraction electrode of the ionization electrode system (3), accelerated, and enters the electrostatic lens electrode (4).
[0018]
In this case, it is not always necessary to extract and accelerate by the extraction electrode. If a sufficient current is drawn, it is better not to apply a voltage to the lead electrode. Since the cluster ion beam already has an energy of several eV to several hundred eV when the ion beam is formed, it can be extracted with relatively high efficiency. The cluster ion beam passing through the electrostatic lens electrode (4) is subjected to convergence and divergence by the electric field generated by the electrostatic lens electrode (4). Convergence divergence depends on the initial energy of the cluster. An aperture (5) is placed at the exit of the electrostatic lens electrode (4), and only the beam having the required cluster size is converged in the aperture of the aperture (5). Other sizes of cluster ion beams are not focused, so the current density is small. The beam exiting the aperture (5) is appropriately converged and deflected by the subsequent converging electrode (6), irradiated onto the workpiece (7) and sputtered.
[0019]
Referring more specifically to FIG. 2, in the gas cluster generation chamber (10), the nozzle (1) as described above is adjustable, and the skimmer (2) is disposed, and the ionization chamber (11). Inside, an ionization electrode system (3), an electrostatic lens electrode (4) and an aperture (5) are disposed, and an ionization vacuum gauge (8) is freely movable up and down. This ionization vacuum gauge (8) measures the cluster beam intensity, and in the case of measurement, the ionization electrode system (3) is not operated. Moreover, this ionization vacuum gauge (8) may be installed between the ionization electrode system (3) and the skimmer (2) for the same purpose. In the irradiation chamber (12), the left and right deflection electrodes (22), the upper and lower deflection electrodes (23), and the shutter (24) are placed in the high voltage chamber (13) following the acceleration electrode (21), and the workpiece is processed. Sputter is applied to the object (7).
[0020]
The high voltage chamber (13) is supported by a support material (25). With such an apparatus, it is possible to actually form a SiO ₂ cured film on the surface of a silicon substrate as a workpiece by controlling the cluster size of CO ₂ gas cluster ions to be within a predetermined range. .
[0021]
【The invention's effect】
As described above in detail, the present invention enables simple, efficient and high-performance sputtering by a method using a cluster size selection method combining an electrostatic lens and an aperture provided in a cluster ion beam irradiation apparatus. .
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a gas cluster ion beam sputtering apparatus.
FIG. 2 is a structural cross-sectional view of a more specific gas cluster ion beam sputtering apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Nozzle 2 Skimmer 3 Ionization electrode system 4 Electrostatic lens electrode 5 Aperture 6 Focusing electrode 7 Work piece 8 Ionization vacuum gauge 10 Gas cluster generation chamber 11 Ionization chamber 12 Irradiation chamber 13 High voltage chamber 21 Acceleration electrode 22 Left and right deflection electrode 23 Up and down Deflection electrode 24 Shutter 25 Support material

Claims (2)

In a cluster ion beam sputtering method using a cluster ion beam irradiation apparatus , a chromatic aberration is generated by an electrostatic lens for a cluster ion beam having energy corresponding to the cluster size, and cluster ions having specific energy are focused on the aperture part. A cluster ion beam sputtering method characterized in that cluster ions are subjected to size selection by bonding and sputtering is performed using the selected cluster ions . As a cluster ion beam apparatus, and a supply of gas of gaseous material at room temperature, the nozzle for gas injection, gas cluster ion beam irradiation with a skimmer for gas cluster ejected from the nozzle to the beam 2. The cluster ion beam sputtering method according to claim 1, wherein an apparatus is used .

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