JPH0576539B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in an electron gun device that irradiates and evaporates a sample in a vacuum to deposit a thin film on the surface of a substrate such as a semiconductor substrate.

(Prior Art) In a conventional electron gun device, as shown in a schematic cross-sectional view in FIG. ) 1 is transferred to an accelerating power source 5 by a grounded accelerating electrode 11.
b, the electron stream 2 is accelerated and becomes an electron stream 2, which is deflected and curved by the magnetic field created by the magnet 3, irradiates the surface of the sample 4 housed in the crucible 6, heats it, and evaporates the sample 4. . The apparatus is configured to deposit a thin film on the surface (lower surface in the figure) of the substrate 20 placed opposite to the sample.

The crucible 6 is water-cooled by a cooling water pipe 7. 10
is a shield plate.

(Problem to be Solved by the Invention) Now, when the sample 4 is heated by the electron irradiation bombardment described above, vapor (and some ions) of the sample 4 is generated, but the evaporation source is placed at the irradiated part of the sample. Limited. In addition, the distribution of vapor pressure of evaporated steam is
Generally, it has an acute angle shape that can be approximated by COS ⁿ⁺¹ θ.

(In this regard, see e.g. Siegfried Schiller,
Ullrich Heisig "Vacuum Deposition" Magne Publishing. reference. ) Therefore, there is a drawback that it is difficult to make the thickness distribution of the deposited film uniform on the surface of the substrate 20.

In order to solve this problem, the sample 4 is
When irradiating the sample 4, the surface of the sample 4 is scanned with the electron stream 2 to slightly expand the area of the evaporation site, or the substrate 20 is rotated around an appropriate axis, for example, the axis 21, in order to average the thin film adhesion. However, in conventional devices, the evaporation source seen from the substrate 20 is mostly a point even when the sample surface is scanned with an electron stream, and as described above, Since the vapor pressure distribution also has an acute angle shape approximated by COS ⁿ⁺¹ θ, there is a limit to the radius of rotation of the substrate that can be adopted. Therefore, it is very difficult to make the thickness distribution of the deposited thin film uniform.

Furthermore, in recent years, for the purpose of mass producing semiconductor devices, there has been a movement to configure the entire device in-line and incorporate thin film deposition into the process to perform continuous deposition. It is also necessary to rotate auxiliary equipment such as a temperature control device for the substrate, and the rotation of the auxiliary equipment makes the structure of the apparatus extremely complicated. Furthermore, a complicated structure is undesirable from the viewpoint of dust generation.

Therefore, with conventional equipment, the only way to obtain a sufficiently uniform thickness distribution of the deposited thin film is to make the distance between the sample and the substrate as large as possible, and this method requires a large equipment. This has caused the inconvenience of unnecessarily increasing sample consumption.

(Objective of the Invention) The present invention solves the above problems and provides an electron gun device that can obtain a good thickness distribution of a deposited film even when forming a thin film in a limited small space without rotating the substrate. For the purpose of providing.

(Means for Solving the Problems) The present invention includes an electron source, an accelerating electrode that accelerates electrons generated by the electron source, and a magnetic field generating means that generates a magnetic field for deflecting the accelerated electrons. In an electron gun device that irradiates a sample with accelerated and deflected electrons to evaporate the sample and deposit a thin film on the surface of a predetermined substrate placed opposite to the sample, the sample is placed at the center of the electron source. A mechanism for rotating the sample around the electron source is arranged, and the magnetic field generating means is configured to irradiate the sample with electrons at a plurality of positions as viewed from the surface of the substrate. This object has been achieved by means of an electron gun device which deflects electrons in such a way that the electrons are deflected.

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

1 to 3 are diagrams for explaining embodiments of the present invention. Components corresponding to the conventional device shown in FIG. 6 described above are given the same reference numerals and their explanations will be omitted.

An electron flow 2 emitted from a filament 1 heated by a current from a filament power source 5a floating on the negative electrode of an accelerating power source 5b whose positive electrode is grounded is accelerated by an accelerating electrode 11 at ground potential and connected to a DC power source 9. Electromagnetic coil 3 as a magnetic field generating means
The sample 4 in the crucible 6 is bent by the magnetic field created by 0.
is irradiated and evaporated to deposit a thin film on the surface of a substrate 20 (not shown) above the electron source 1.

In the apparatus of this embodiment, unlike the conventional apparatus, the crucible 6 and the sample 4 are arranged in an annular shape around an axis 22 passing through the electron source 1, as is clear from FIGS. 1 and 3.

Also, the details of the electromagnetic coil 30 are as follows:
As shown in FIG. 2, air-core coils 31 to 38 (represented by 30) are fixedly arranged in a ring around an axis 22 passing through the electron source 1, and the excitation of these coils is as follows: For example, in the order of the coil numbers, only one of the coils is successively connected to the power source 9 and excited. (Description of the detailed circuit configuration of these connections will be omitted.)
Therefore, the deflection state of the electrons changes circumferentially by the electromagnetic coil 30 that is sequentially excited, and the electrons are successively irradiated along the surface of the annular sample 4. That is, the sample is irradiated with electrons at a plurality of positions.

Note that the grounded fixing plate 18 prevents the radiation emitted from the filament 1 from directly adhering to the substrate.

Further, as seen in FIG. 3, the exhaust device 19 (and the exhaust hole) is disposed directly below the filament 1 in order to prevent the filament from being deteriorated by the gas when the gas is introduced.

FIG. 4 shows a schematic diagram of another embodiment of the invention.

In the apparatus shown in FIG. 4, a permanent magnet 30 is used as a magnetic field generating means.

The permanent magnet 3 is directly connected to the rotating shaft of the motor 39 by an arm 300, and is adapted to rotate around the shaft 22 passing through the electron source 1 at a rather slow speed.

The crucible 6 of this apparatus is of the same conventional type as shown in FIG. 6, and is connected to the permanent magnet 3 by an arm 301 so as to rotate together with the permanent magnet 3. Therefore, in the embodiment as well, the deflection state of electrons changes circumferentially, and the crucible 6 rotates to follow the changes. Therefore, when viewed from the substrate (not shown in FIG. 4), the position of electron irradiation on the sample 4 changes circumferentially. That is, the sample 4 is irradiated with electrons at a plurality of positions when viewed from the substrate surface. Furthermore, "viewed from the board surface" means
This means that even if the crucible 6 is at the same position, it may be at a plurality of positions when viewed from the substrate surface. Although detailed drawings and explanations are omitted, water for water cooling is provided by arms 300 and 301.
introduced through.

Now, the electron gun device shown in Fig. 1 is grounded in a conventional evaporation apparatus, and the rotating magnet shown in Fig. 4 is used instead of the coil 30, and the distance between the sample and the substrate is set to 100.
mm, when the diameter of the ring of the annular sample is 100 mm,
Even when the substrate 20 was not rotated, it was possible to deposit an Al thin film with a film thickness distribution within ±10% over a diameter of 100 mm on the surface of the silicon substrate.

On the other hand, the thickness distribution of the Al thin film obtained by replacing the electron gun with a conventional electron gun device is ±
The results were poor, exceeding 30%. Both graphs are shown together in FIG. In this example, the case is a
The conventional curve is the b curve.

Furthermore, at this time, the consumption amount of sample Al required to deposit the same film thickness was about 1/10 to 1/20 in the case of the example of the present invention as in the case of the conventional apparatus.

Furthermore, a high deposition rate and therefore rapid film thickness formation were possible.

Since the distance between the sample and the substrate can be greatly shortened, the entire apparatus can be made much smaller than before, and this effect is also extremely large.

(Effect of the invention) According to this invention, without rotating the substrate,
A thin film with excellent thickness distribution can be deposited on a substrate using a small space and a compact and economical apparatus.

[Brief explanation of the drawing]

FIG. 1 is a schematic front sectional view of an embodiment of the present invention. FIG. 2 is a detailed plan view of the electromagnetic coil section.
FIG. 3 is a schematic perspective view thereof. FIG. 4 is a schematic front sectional view of another embodiment of the invention. Figure 5 is a graph of the thickness distribution of the deposited Al thin film. FIG. 6 is a front sectional view of a conventional device. 1... Filament, 2... Electron flow, 3... Permanent magnet, 4... Sample, 5a... Filament power source, 5b... Acceleration power source, 6... Crucible, 7... Cooling water pipe, 18... Fixed plate , 19... exhaust system, 3
0-38...Electromagnetic coil, 39...Motor, 3
00,301...Arm.

Claims (1)

[Claims] 1. An electron source comprising an electron source, an accelerating electrode for accelerating electrons generated by the electron source, and a magnetic field generating means for generating a magnetic field for deflecting the accelerated electrons, and for accelerating and deflecting the accelerated electrons. In an electron gun device that irradiates a sample with electrons to evaporate the sample and deposit a thin film on the surface of a predetermined substrate placed opposite to the sample, the sample is arranged in a ring shape with the electron source at the center. Alternatively, a mechanism for rotating the sample around the electron source is disposed, and the magnetic field generating means deflects the electrons so that the sample is irradiated with electrons at a plurality of positions when viewed from the substrate surface. An electron gun device characterized in that it is an electronic gun device. 2. The electron gun device according to claim 1, wherein the magnetic field generating means uses a plurality of magnetic field coils arranged in a ring shape and sequentially excites the plurality of magnetic field coils. 3. The electron gun device according to claim 1, wherein the magnetic field generating means uses a permanent magnet and rotates the permanent magnet around an axis passing through the electron source.