JPH0576540B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is an electron beam evaporation method in which a raw material is irradiated with electrons in a vacuum, heated and evaporated to deposit a thin film on the surface of a substrate such as a semiconductor substrate. Concerning improvements to equipment.

(Prior art and its problems) In a conventional electron beam evaporation apparatus, as shown in a schematic cross-sectional view in FIG.
The source material 5 is irradiated by being deflected by the magnetic field created by the magnet 6, but the reflected electrons and secondary electrons 3 and 4, which have a very harmful effect on the semiconductor substrate 20 and the deposited film on its surface, are The electron beam was deflected again by the magnetic field created by the magnet 6, and was eventually taken into the electron gun body 7.

However, since these reflected electrons and secondary electrons are scattered with various strengths in various directions, it is difficult to capture all of the electrons 3 and 4 into the electron gun body 7 by the magnetic field created by the magnet 6. Since the removal of stray electrons is insufficient, there is a problem, for example, that stray electrons fly to the base without being captured by the electron gun body.

Some conventional devices were configured to actively capture reflected electrons 3 and 4 by placing an auxiliary magnet at a location 10 indicated by a two-dot chain line in the figure. Removal of stray electrons was not always sufficient.

On the other hand, in an electron beam evaporation system that forms a film by ionizing raw materials evaporated by electron beam irradiation, an ionization mechanism must be installed between the electron gun and the substrate, making the system large and expensive. There was a problem with it sticking to the surface.

(Objective of the Invention) An object of the present invention is to provide a novel electron beam evaporation device that prevents stray electrons as described above from reaching a substrate, and furthermore, has the function of ionizing evaporation raw materials even though it is a small device. With the goal.

(Means for Solving the Problems) The present invention accelerates electrons generated in an electron source by applying a high voltage in a vacuum, and deflects the accelerated electrons by a magnetic field to form a crucible. In an electron beam evaporation apparatus that irradiates a raw material contained in a container, heats, melts and evaporates the raw material, and deposits a thin film on a substrate such as a semiconductor substrate placed opposite to the raw material. In the space between the raw material material and the substrate, electrons reflected from the raw material material and secondary electrons emitted from the raw material material are captured without being dispersed to form an electron cloud, and this electron cloud is used to evaporate the evaporation. The above object is achieved by using an electron beam evaporation apparatus provided with a magnetic field that ionizes the substance.

(Example) Hereinafter, an example of the present invention will be described in detail using the drawings.

FIG. 1 is a schematic cross-sectional view of an embodiment of the invention. Moreover, FIG. 3 is a side sectional view of the ionization pole piece. As shown in FIGS. 1 and 3, the electron gun main body 7 used in the electron beam evaporation apparatus of this embodiment includes a horizontally long round bar-shaped magnet 6 and a pair of magnets provided at both ends of the magnet 6. An electron beam deflection pole piece 12 and a pair of ionization pole pieces 11 provided to sandwich the outside of the pair of electron beam deflection pole pieces 12.
It has As shown in FIG. 3, the pair of ionization pole pieces 11 extend toward an upper substrate (not shown), and both tip ends are
They face each other at a predetermined height, creating a cloud of electrons as described below. The electron beam 2 emitted from the filament 1 is deflected by the magnetic field created by the magnet 6 and is irradiated onto the raw material 5 . The raw material substance 5 is evaporated by the energy of this electron beam 2. At this time, most of the electrons 2 irradiated to the raw material substance 5 are taken into the raw material substance, but are reflected without jumping into the raw material substance 5. As described above, there are also quite a few electrons 3 and 4 emitted from the raw materials as secondary electrons.

Among these electrons 3 and 4, the electron 3 reflected at a relatively shallow angle is deflected by the magnetic field and taken into the electron gun body 7 as in the conventional case. However, the electrons 4 emitted at a large angle, that is, in the direction of the substrate, are caught by the magnetic field created by the ionization pole piece 11 provided in the present invention and are not dispersed, creating a cloud of electrons there.

This cloud of electrons is created in the space in which the evaporated material travels toward the substrate.

Due to this effect, the apparatus of this embodiment can drastically reduce stray electrons reaching the substrate compared to conventional electron beam evaporation apparatus, and furthermore,
The cloud of electrons formed by being captured by the magnetic field created by the ionization pole piece 11 ionizes the raw material that evaporates and flies out during the flight due to the electron beam irradiation, and sends it out to the substrate with stronger energy. In other words, this cloud of electrons plays the role of a conventional ionization processing device.

Although the device becomes somewhat larger, instead of the ionization pole piece 11 provided in this embodiment,
A similar effect can be obtained by constructing a magnetic circuit passing through this portion using a magnet provided separately from the magnet 6.

Furthermore, the effect is the same whether the magnet that creates the magnetic field is a permanent magnet or an electromagnet.

(Effects of the Invention) According to the present invention, it is possible to prevent harmful stray electrons from reaching the substrate and to promote ionization of the evaporated raw material.

[Brief explanation of the drawing]

FIG. 1 is a schematic front sectional view of an embodiment of the present invention. FIG. 2 is a similar conventional diagram. FIG. 3 is a side sectional view of the ionization pole piece. 1...Filament, 2...Electron beam, 3,
4... Backscattered electrons or secondary electrons, 5... Raw material, 6... Magnet, 7... Electron gun body, 8... Water cooling pipe, 9... Vacuum container, 10... Auxiliary magnet,
11... Pole piece for ionization. 12...Pole piece for electron beam deflection.

Claims (1)

[Claims] 1 A high voltage is applied in a vacuum to accelerate electrons generated in an electron source, and the accelerated electrons are deflected by a magnetic field to form a raw material contained in a crucible. In an electron beam evaporation apparatus that irradiates the raw material, heats, melts and evaporates the raw material, and deposits a thin film on a substrate such as a semiconductor substrate placed opposite to the raw material. In space, electrons reflected by the raw material and secondary electrons emitted from the raw material are captured without being dispersed to form an electron cloud, and the evaporated material is ionized by this electron cloud. An electron beam evaporation device characterized by providing a magnetic field.