JPH0249385B2 - PURAZUMACVD SOCHI - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to the formation of interlayer insulating films, passivation films, etc. in amorphous semiconductors such as amorphous silicon and integrated circuits by decomposing raw material gas by plasma discharge. Regarding applied plasma CVD equipment.

(Prior art) Plasma CVD equipment, which has been conventionally used for depositing a-Si (amorphous silicon) films and passivation films, uses a gas introduction mechanism and an exhaust mechanism to control the interior to a desired gas composition, flow rate, and pressure. Parallel plate electrodes are provided in a vacuum chamber that can be adjusted to the desired temperature, and high-frequency power is applied to these electrodes to turn the reaction gas into plasma.The substrate on which the film is to be formed is mounted on a suitable support device within the vacuum chamber. is heated to a desired temperature, and plasma-formed and decomposed gas species are deposited on its surface.

(Problems to be Solved by the Invention) In such conventional plasma CVD equipment, the rate at which a film is deposited on a substrate is usually 1 to 3 Å/sec, and it is industrially difficult to increase this deposition rate. desired. When the high-frequency power density of the electrode is increased in order to improve the deposition rate, the incident energy of ions incident on the substrate surface increases, causing defects in the deposited film and also increasing the reaction between active species in the gas phase. This is not preferable because it causes non-uniformity in the film structure.

On the other hand, it is possible to improve the deposition rate by using easily decomposed disilane gas, trisilane gas, fluorinated silane gas, etc. as a reaction gas, but these gases need to be handled more carefully than silane gas, and Generally, good film quality cannot be obtained.

An object of the present invention is to provide a plasma CVD apparatus that can improve the deposition rate of a film without deteriorating the film quality.

(Means for solving the problems) In order to achieve the above object, according to the present invention,
A high-frequency voltage is applied to parallel plate electrodes installed in a vacuum container, and the reaction gas introduced into the vacuum container is turned into plasma, thereby forming a thin film on a substrate mounted on a support device equipped with a heating mechanism. In the plasma CVD apparatus, a groove is formed on the surface of the electrode to which a high frequency voltage is applied, and a magnetic field forming device for forming a magnetic field perpendicular to the high frequency electric field is provided in the groove.

In this configuration, a positioning device is provided for positioning the substrate at a distance with respect to a plasma region concentrated by a magnetic field orthogonal to the high-frequency electric field.

According to another feature of the invention, a moving device is provided for moving at least one of the parallel plate electrode, the substrate, and the magnetic field forming device.

(Function) In the device of the present invention configured as described above, a groove is formed on the surface of the electrode to which a high frequency voltage is applied, and the magnetic field generating device generates a magnetic field orthogonal to the electric field there, so that the groove is Electrons from the space are captured by the magnetic field, forming a prism with extremely high electron density. In this electron-dense plasma,
The frequency of collisions between gas species and electrons increases, promoting decomposition of the reactive gas. Therefore, the concentration of active species contributing to film formation increases within the groove, and the deposition rate of the film on the portion of the substrate facing the groove increases greatly.

Furthermore, by moving at least one of the parallel plate electrodes, the substrate, and the magnetic field forming device using a moving device, it is possible to scan the substrate surface in a plasma region with high electron density, depositing a film with a uniform distribution on the substrate. I can do it.

(Embodiment) An embodiment of the present invention will be described based on the drawings. In FIG. 1, reference numeral 1 is a vacuum vessel, 2 is a gas introduction device for introducing a reaction gas such as hesilane gas into the vacuum vessel 1, and 3 is a vacuum vessel. An exhaust device for evacuating the inside of the vacuum container 1 is shown. A parallel plate type electrode consisting of a high frequency application electrode 4 and a ground electrode 5 is provided inside the vacuum vessel 1, and a high frequency power source 7 is connected to the high frequency application electrode 4 via a matching circuit 6. The ground electrode 5 also serves as a support device for the substrate 8, and a heating mechanism 9 for heating the substrate 8 is provided inside. 10 is a heating power source.

This configuration is similar to the conventional plasma CVD apparatus, but in the present invention, an annular or other groove 11 is formed on the surface of the high frequency application electrode 4, that is, the surface facing the ground electrode 5. A magnetic field forming device 12 made of a permanent magnet or the like is provided in the groove 11 to form a magnetic field perpendicular to the high frequency electric field. Although the magnetic field forming device 12 is provided inside the high frequency application electrode 4 in the illustrated example, the present invention is not limited thereto, and may be provided outside and behind the electrode 4.

The operation of the device shown in the first figure is as follows.

First, the interior of the vacuum container 1 is adjusted to a desired gas composition, gas flow rate, and pressure using the reaction gas introduction device 2 and the exhaust device 3, and then a high frequency voltage is applied to the high frequency application electrode 4 to connect this and the ground electrode 5. A glow discharge is generated during this period. The electrons generated in the plasma at this time are captured in the groove 11 of the high-frequency application electrode 4 by a magnetic field orthogonal to the high-frequency electric field formed by the magnetic field forming device 12, and a plasma with extremely high electron density is generated within the groove 11. A region is formed. As a result, decomposition of the reaction gas is promoted within the groove 11,
A film is formed on the substrate 8 of the ground electrode 5 at a particularly high speed in the portion facing the groove 11. Specifically, even if the power applied to the high frequency application electrode 4 is the same as that of the conventional one, the deposition rate can be increased several times by 10
It can be done as Å/sec.

Note that the substrate 8
are installed at a distance, and in the example shown in the first figure, the distance can be freely adjusted by moving the ground electrode 5 using a positioning device 13.

The embodiment shown in FIG. 2 shows another feature of the present invention, in which the high frequency application electrode 4 is connected to a moving device 14 such as an electric motor that rotates and moves together with the magnetic field forming device 12, During processing, the surface of the substrate 8 is scanned by the plasma region within the moving groove 11, so that the thickness distribution of the thin film formed on the substrate 8 is made uniform.

As shown in the third diagram, the moving device 14 includes a magnetic field forming device 1 rotatably provided within the high frequency application electrode 4.
It is also possible to connect the substrate 8 to the ground electrode 5 to give it a rotational movement as shown in FIG. It is also possible to provide a positioning device 13 on the ground electrode 5 to adjust the distance between the substrate 8 and the plasma region.

Although not shown, two or more of the electrodes 4 and 5, the substrate 8, and the magnetic field forming device 12 may be moved simultaneously.

(Effects of the invention) As described above, the plasma CVD apparatus of the present invention has the following effects:
A groove is formed on the surface of the high-frequency application electrode, and a magnetic field is generated in the groove perpendicular to the high-frequency electric field by a magnetic field forming device, so that a plasma region with high electron density can be formed by being confined within the groove. It is possible to form a thin film at high speed on a substrate facing the substrate, and since there is no need to use large amounts of electricity or special gas, a film of good quality can be obtained. Furthermore, since at least one of the electrode, the substrate, and the magnetic field forming device is moved by the moving device,
It has the advantage of being able to scan the substrate in the plasma region and form a thin film with a uniform thickness distribution.

[Brief explanation of drawings]

1 to 4 are schematic cross-sectional diagrams of embodiments of the present invention. DESCRIPTION OF SYMBOLS 1... Vacuum container, 4, 5... Parallel plate electrode, 8... Substrate, 9... Heating mechanism, 11... Concave groove, 12... Magnetic field forming device, 13... Positioning device, 14... Movement device.

Claims (1)

[Scope of Claims] 1. A substrate mounted on a support device equipped with a heating mechanism by applying a high frequency voltage to a parallel plate type electrode provided in a vacuum container and converting a reaction gas introduced into the vacuum container into plasma. In a plasma CVD apparatus configured to form a thin film thereon, a groove is formed on the surface of an electrode to which a high frequency voltage is applied, and a magnetic field forming device is provided within the groove to form a magnetic field perpendicular to the high frequency electric field. A plasma CVD device featuring: 2. The plasma CVD apparatus according to claim 1, further comprising a positioning device that positions the substrate at a distance with respect to a plasma region concentrated by a magnetic field orthogonal to the high-frequency electric field. 3. A thin film is formed on a substrate mounted on a support device equipped with a heating mechanism by applying a high frequency voltage to parallel plate type electrodes provided in the vacuum container and turning the reaction gas introduced into the vacuum container into plasma. In such a plasma CVD apparatus, a groove is formed on the surface of the electrode to which a high frequency voltage is applied, and a magnetic field forming device for forming a magnetic field orthogonal to the high frequency electric field is provided in the groove, and the parallel plate electrode and the substrate are connected to each other. A plasma CVD apparatus comprising a moving device for moving at least one of the magnetic field forming devices.