JPS63162860A - Thin film vapor deposition device - Google Patents

Abstract

PURPOSE:To execute vapor deposition of a thin film having high quality, by permitting intermittent impression of an ionizing voltage between a filament and electron drawing out electrode, capturing the electric current of cluster ions flying toward a substrate and measuring the size of the clusters. CONSTITUTION:Vapor of a material 5 to be deposited by evaporation is ejected from an evaporation source 8 provided in a vacuum vessel 1 to generate the clusters. The clusters are ionized by drawing out the thermoelectrons emitted from the filament 9 by the electron drawing out electrode 10 and bringing the same into collision against the clusters. The cluster ions formed in such a manner are accelerated by an accelerating electrode 14 and are bombarded together with the neutral clusters against the substrate 10 to form the thin film by vapor deposition on the substrate. The thin film vapor deposition device constituted in the above-mentioned manner is so formed that either of a power supply 30 for ionization and a circuit 35 for intermittent impression of the ionizing voltage can be selected by a selector switch 36; further, a Faraday cage 30 to capture the cluster ions flying toward the substrate 10 is disposed. The ordinary thin film vapor deposition is thereby executed. The cluster sizes are measured at need and the control thereof is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to cluster size measurement in a cluster ion beam evaporation apparatus.

[Conventional technology]

In the thin film layer deposition method using the cluster ion beam evaporation method, the vapor of the material to be deposited on the substrate is ejected in a vacuum chamber, and a large number of atoms in the vapor are loosely bonded to clusters (clumps of atoms). ), showering the cluster with electrons to turn the cluster into a cluster ion in which one atom is ionized, and accelerating the cluster ion to collide with the substrate, thereby depositing a thin film on the substrate. It's a method. An example of a method for forming a thin film using this vapor deposition method is shown in FIGS. 4 and 5 in Japanese Patent Publication No. 54-9592, for example. Fourth
The figure is a cross-sectional view schematically showing a conventional thin film deposition apparatus, and FIG. 5 is a perspective view showing a partial cross-section of its main parts. (
2) is an exhaust passage for exhausting the inside of the vacuum chamber (11), and this is connected to a vacuum exhaust device (not shown).
3) is a vacuum pulp that opens and closes the exhaust passage (2).

(4) is a closed crucible equipped with a nozzle (26) with a diameter of 11 to 21 m, and a vapor deposition raw material (5), such as a
ll(Ag) is accommodated. (6) is the above crucible (4)
A heating filament (7) is a heat shield plate that blocks radiant heat from the filament (6), and the crucible (4) and the heating filament (6)
and a heat shield plate (7), an evaporation source (8) that spouts vapor deposition raw materials into the vacuum chamber (1) to generate clusters.
) is formed. Note that (13a) is thermionic electrons emitted from the heating filament (6), (19 is an insulating support member that supports the heat shield plate (7), (21 is a support stand that supports the crucible (4), (25) is an insulating support member that fixes the support stand 12m to the vacuum chamber.

(9) is an ionization filament that emits thermionic electrons (13b) for ionization, and α1 is an ionization filament (9
), αυ is a heat shield plate that blocks radiant heat from the ionized filament (9), and αυ is a heat shield plate that blocks radiant heat from the ionized filament (9), the electron extraction electrode α (to) and the heat shield plate αυ form an ionization means U for ionizing the clusters from the explosion source (8).

Note that (23) is an insulating support member that supports the heat shield plate 0υ. Q41 is an acceleration means, that is, an acceleration electrode, which accelerates the ionized cluster ions Ql and causes them to collide with the non-ionized neutral cluster α9 against the thin film forming substrate α to form a thin film. It has a structure in which a potential can be applied between the electron extraction electrode a and the electron extraction electrode a. Note that (24) is an insulating support member that supports the accelerating electrode a, (22) is a substrate holder that supports the substrate OI, (21) is an insulating support member that supports the substrate holder (22), and 0η is a cluster ion support member. This is a cluster beam consisting of αe and a neutral cluster α9.

FIG. 6 is a cross-sectional view schematically showing a conventional thin film deposition apparatus including a power source. In the figure, (27) is a heating filament power supply used for the heating filament (8), and (28) is a voltage applied between the crucible (4) and the heating filament (6) to heat the crucible by electron impact. It is a crucible heating power source for. (29) is an ionization filament power supply used for electrically heating the ionization filament (9), and (30) is an ionization power supply that applies an ionization voltage between the electron extraction electrode αψ and the ionization filament (9). (31) is an accelerating power source that forms an accelerating electric field between the electron extraction electrode 011B and the accelerating electrode 0. The above heating filament electric m (27),
A thin film deposition power source (32) is composed of a crucible heating type fi (28), an ionizing filament electric current 1fl (29), an ionizing electric current a (30), and an acceleration power source (31). Note that (33) is a current introduction terminal for introducing current into the vacuum chamber (1), and (34) is an ammeter for measuring the ion current flowing into the substrate Ql.

Next, the operation will be explained.

To explain the case of forming a thin silver film on the substrate am, first, silver (5) is filled in the crucible (4), and the air in the vacuum chamber (1) is evacuated by the vacuum exhaust device to remove the vacuum chamber ( 1) Create a vacuum of about 10" Torr. Next, the heating filament (6) is energized to generate heat, and the heat is radiated from the heating filament (6) or emitted from the filament (6). When the electrons (13a) collide with the crucible (4), the silver (5) in the crucible (4) is heated and evaporated by the electron impact.Then, the vapor pressure of the silver (5) in the crucible (4) increases. 0.1 to several tens of tons
When the temperature is raised to about 0.35 to 30.0 m, the steam ejected from the nozzle (26) expands adiabatically due to the pressure difference between the crucible (4) and the vacuum chamber (1), and forms a mass of loosely bonded atoms called a cluster. Becomes a group of atoms.

This cluster beam qTI collides with the hot electrons (13b) extracted from the ionized filament (9) by the electron extraction electrode αφ, so one atom of some of the clusters is ionized and becomes a cluster ion. It becomes αe. This cluster ion αQ is moderately accelerated by the electric field formed between the acceleration electrode Q41 and the electron extraction electrode OI, and when the non-ionized neutral cluster Q51 is injected from the crucible (4), it has kinetic energy. As it collides with the substrate (to), the substrate Q
This causes a thin silver film to be deposited on the substrate attr.

In this manner, thin film deposition by the cluster ion beam evaporation method forms a thin film using cluster ions that have a single charge and are composed of several dozen to several tens of atoms. Here, the energy of the cluster ions is determined by the accelerating voltage, so by adjusting the accelerating voltage and the energy given to the cluster ions, the energy per atom constituting the cluster can be controlled. Here, the value of energy per atom suitable for vapor deposition is determined, and by controlling the energy per atom, a high-quality thin film with excellent crystallinity, mechanical, and electrical properties can be produced on the substrate. Can be formed.

[Problem that the invention seeks to solve]

However, conventional thin film deposition equipment has a cluster size (
Since there is no means to measure the number of atoms that make up a cluster, it is not possible to know the energy per atom, and the operating conditions for the equipment when depositing a thin film must be determined through trial and error. There was a problem that it was not possible.

On the other hand, one of the means for measuring cluster size is the quim-of-flight method. This method is described, for example, in a magazine (Electron/Ion Beam Handbook, published by Nikkan Kogyo Shimbun, pp. 261-262),
This method performs ionization of clusters in a pulsed manner and measures the temporal changes in the ion current arriving at the substrate, but it uses a specially structured evaporation source and ionization means, as well as a complicated power supply, which is required for thin film deposition equipment. It was too impractical. For the above reasons, there has been a demand for the development of a thin film deposition apparatus that is equipped with a means for measuring cluster size and that can be used for production.

This invention was made to solve the above-mentioned problems, and it can be used as needed by using the conventional evaporation source and ionization means used for thin film production, and by only partially modifying the conventional power source. It is an object of the present invention to provide a thin film deposition apparatus that can measure cluster size by using the same method and can also perform normal thin film deposition.

[Means for solving problems]

A thin film deposition apparatus according to the present invention includes a vacuum chamber maintained at a predetermined degree of vacuum, and a vapor of a substance provided in the vacuum chamber to be vapor-deposited onto a substrate. an evaporation source that generates clusters in which are loosely coupled; a filament that emits thermoelectrons to ionize the clusters; an electron extraction electrode that extracts the thermoelectrons and causes them to collide with the clusters; the filament and the electron extraction an ionization power supply that applies an ionization voltage between the electrodes; an acceleration electrode that accelerates the ionized cluster ions and causes them to collide with the substrate together with unionized neutral clusters to deposit a thin film; an ionization voltage intermittent application circuit that intermittently applies an ionization voltage between the filament and the electron extraction electrode in order to extract hot electrons; a changeover switch that selects either this circuit or the ionization 'R source; The device is equipped with an ion current trap that traps the ion current of cluster ions flying toward the substrate.

[Effect]

The intermittent ionization voltage application circuit in this invention is provided for cluster size measurement using the time-of-flight method.When measuring the cluster size, when the ionization voltage intermittent application circuit is selected by the changeover switch,
Ionize the cluster in a pulsed manner. Since the time required for the cluster ions formed at this time to arrive at the substrate differs depending on the cluster size, the cluster size can be determined by measuring the ion current near the substrate with an ion current trap. As a result, the energy per atom that makes up the cluster can be determined, and this technique can be controlled to produce a high-quality film.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.
1 is a schematic diagram of a thin film deposition apparatus according to an embodiment of the present invention, and FIG. 2 shows an ionization voltage intermittent application circuit of the thin film deposition apparatus shown in FIG. In Figure 1,
Reference numeral (35) denotes an ionization voltage intermittent application circuit, which supplies a pulsed ionization voltage between the filament (9) and the electron extraction electrode 0III by means of a changeover switch (36) during cluster size measurement. During normal vapor deposition, the output of the ion ring a (30) is directly taken out by the changeover switch (36). (37) is a pulse generator,
The ionization voltage intermittent application circuit is operated based on the pulses formed here. (38) is an ion current trap for measuring ion current, such as a Faraday cage, which is attached to the rotating introduction terminal (39) and used by moving to the bottom of the substrate α when measuring the cluster size. (40) is a current amplifier that amplifies the ion current flowing into the Faraday cage (38), and (41) is a function that integrates the output signal of the current amplifier (40), averages it, reduces noise, and displays it. It is a synchroscope with a In addition, in Fig. 2, (43) is a photocoupler,
(45) is an inverter, (46) is an FET, and (5
2) is an output terminal on the electron extraction electrode side, and (53) is an output terminal on the filament side.

Next, the operation will be explained.

During normal vapor deposition operation, the output of the ionization power source (30) is selected by the changeover switch (36), and the operation is carried out in the same manner as in the past.

When measuring cluster size, first turn on the selector switch (36).
The output of the ionization voltage intermittent application circuit (35) is selected by. Next, operate the pulse generator (37) so that the width is 0.
．． A pulse with a period of 1 to 10 m sec was generated for 5 to 56 sec, and the ionization voltage intermittent application circuit (3
5). This pulse is isolated and inputted by a photocoupler (43), inverted by an inverter (45), and then output to the FE.
T (46) is added to the gate. Therefore, when the pulse is input, the FET (46) is turned on, so that the ionization filament side output terminal (53)
The potential decreases, and the electron extraction electrode side output terminal (52)
An ionization voltage is generated between the Note that the ionization voltage and current generated here are preferably about the same as the cluster ionization conditions during normal thin film deposition, that is, the ionization voltage is about 50 to 300 V, and the current is about 10 to 400 mA. It's good. When an ionizing voltage is intermittently applied to the ionizing means (2) in this manner, ionizing thermoelectrons are intermittently extracted and cluster ions are intermittently formed. These cluster ions are accelerated between the electron extraction electrode α1 and the acceleration electrode α1 by an acceleration voltage of 0.5 to 2V, and are then accelerated between the electron extraction electrode α1 and the acceleration electrode α1.
41 to the Faraday cage (38), the plane flies at nearly constant speed. Since cluster ions have different speeds depending on their cluster size, there is a difference in the time it takes for them to arrive at the Faraday cage. Therefore, the cluster size can be determined by amplifying the current flowing into the Faraday cage (38) with the amplification 2S (40) and processing it with a synchroscope. Here the cluster
Since the energy of the ion is determined by the accelerating voltage, it is possible to know and control the energy per atom constituting the cluster.

Note that it is also possible to obtain the cluster size spatial distribution of the cluster beam surface by measuring the cluster size while moving the Faraday cage (38) by operating the rotation introduction terminal (39).

In the above embodiment, the pulse generator (37) is provided outside the thin film electrodeposition m (32), but it may be provided inside the thin film deposition amount fi (32).

Further, in the above embodiment, the Faraday cage (38) was attached to the rotation introduction terminal (39), but the substrate a
The same effect can be obtained even if it is installed at the end of m.

Further, the thin film deposition apparatus may be provided with a shutter that blocks the cluster beam 0η as necessary. In the case of such a device, if a Faraday cage (38) is attached to the shutter (54) as shown in Fig. 3, the cluster size is measured with the shutter (34) closed, and the desired cluster size is determined. Once the size is obtained, the shutter (34) can be opened to perform the deposition.

In the above example, a Farab-cage (3 days) was used to detect the ion current, but in cases where precision is not required, the time-dependent detection of the current flowing into the substrate al may be performed without using a Faraday cage. Measuring the change also allows us to determine the approximate cluster size.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a vacuum chamber maintained at a predetermined degree of vacuum, and a vapor of a substance provided in the vacuum chamber to be deposited on a substrate is spouted into the vacuum chamber. an evaporation source that generates a cluster in which a large number of atoms are loosely bonded; a filament that emits thermionic electrons to ionize the vapor cluster; an electron extraction electrode that extracts the thermionic electrons and causes them to collide with the cluster; and the filament. and an ionization power source that applies an ionization voltage between the electron extraction electrode and the electron extraction electrode, and an acceleration electrode that accelerates the ionized cluster ions and causes them to collide with the substrate together with the unionized neutral clusters to deposit a thin film. , an ionization voltage intermittent application circuit that intermittently applies an ionization voltage applied from the filament to the ionization electron extraction electrode, a changeover switch that selects either this circuit or the ionization power source, and a cluster that runs toward the substrate.・Since it is equipped with an ion current trap that captures the ion current of ions, it is possible to perform normal vapor deposition and measure the cluster size, and by measuring the cluster size, it is possible to know the energy per atom of the cluster. Because it is possible to
This has the effect of providing a thin film deposition apparatus that can control this and efficiently obtain a high quality thin film.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a thin film deposition apparatus according to an embodiment of the present invention, FIG.
The figure relates to another embodiment of the present invention, and is a cross-sectional view of the configuration of a thin film deposition apparatus excluding a power source. FIG. 4 is a cross-sectional view of a conventional thin film deposition apparatus excluding a power source. FIG. FIG. 6 is a perspective view partially showing the main parts of the vapor deposition apparatus in cross section, and FIG. 6 is a configuration diagram of a conventional thin film vapor deposition apparatus. fil...vacuum chamber, (5)...evaporation substance, (8).
...Evaporation source, (9)...Filament, Frame...Electron extraction electrode, (13b)...Thermoelectron, α ship...Acceleration electrode, a9...Cluster, αe...Cluster Ion, αl...Substrate, (30)...Ionization power source,
(35)...Ionization voltage intermittent application circuit, (36)...
...Choice switch, (38)...Faraday cage. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa Figure 2 Figure 3 Figure 4 1517 Lass 9. I6.7 Umatari, 4 on Figure 5

Claims (2)

[Claims] (1) A vacuum chamber is maintained at a predetermined degree of vacuum, and the vapor of the substance to be deposited on the substrate is spouted into the vacuum chamber, and many atoms in the vapor are loosely bonded. an evaporation source that generates clusters, a filament that emits thermoelectrons to ionize the clusters, an electron extraction electrode that extracts the thermoelectrons and causes them to collide with the clusters, and an ionization device between the filament and the electron extraction electrode. An ionization power supply that applies a voltage, an acceleration electrode that accelerates the ionized cluster ions and causes them to collide with the substrate together with unionized neutral clusters to deposit a thin film, and thermionic electrons for ionization from the filament. An ionization voltage intermittent application circuit that intermittently applies an ionization voltage between the filament and the electron extraction electrode for extraction, a changeover switch that selects either this circuit or the ionization power source, and a cluster that flies in the direction of the substrate. - Thin film deposition equipment equipped with an ion current trap that captures ion current. (2) The thin film deposition apparatus according to claim 1, wherein the ion current trap is a Faraday cage.