JPS62124277A - Plasma cvd device - Google Patents

Abstract

PURPOSE:To make high-speed deposition of films having good film quality and uniform film thickness distribution by impressing a high-frequency voltage to an electrode provided in a vacuum vessel to form plasma and providing a device for forming a magnetic field of a closed loop type onto the above-mentioned electrode. CONSTITUTION:The high-frequency voltage is impressed from a high-frequency power source 7 to a parallel flat plate type electrode 4 disposed to face the ground electrode 5 in a vacuum chamber 1 having an evacuation mechanism 3 to convert the reactive gas introduced from an introducing mechanism 2 to plasma, so that the thin film is formed on a substrate 10 mounted on the above-mentioned ground electrode 5 having a heating mechanism 11. The device consisting of a magnet 8 and magnetic plate 9 is provided on the high-frequency impressing electrode 4 of the plasma DVD device constituted in the above-menioned manner to form the magnetic field of a closed loop type, thus forming the high-density plasma. the thin film is thereby formed at a high speed on the surface of the substrate 10 on the ground electrode 5 positioned by a driving mechanism 13. The substrate 10 and the magnetic field are relatively scanned, by which the film having the good film quality and uniform film thickness distribution is easily formed.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to decomposing raw material gas by plasma discharge and depositing amorphous semiconductors such as amorphous semiconductors and insulating films in integrated circuits. The present invention relates to a plasma CVD apparatus that can be used.

[Conventional technology]

Conventionally, hydrogenated amorphous silicon (hereinafter referred to as a-8i: H ) is usually plus-r OVD? 4, and it is said that the film quality produced by this method is the best. In this method, silane gas is decomposed by high frequency glow discharge to deposit an a-8i:H film on the substrate. A plasma CVD apparatus conventionally used for this purpose is composed of parallel plate electrodes including a cathode to which a high frequency voltage is applied and a grounded anode.

[Problem that the invention seeks to solve]

By the way, in a plasma CVD apparatus with such a configuration,
The deposition rate of a-8i:H is usually about 2 to JA/see. Therefore, if the radio frequency power density is increased in order to increase the deposition rate, the reaction between the active species generated in the plasma in the gas phase becomes dominant, resulting in non-uniformity in the film structure. At the same time, the energy of the ion species generated in the plasma that enters the film increases, causing defects in the film. For these reasons, it is difficult to further increase the deposition rate using this method, since an increase in power density generally leads to a decrease in film quality.

On the other hand, attempts have been made to increase the deposition rate by using disilane or trisilane as a raw material gas instead of silane, but these gases are extremely dangerous and difficult to handle, and they are difficult to handle in exhaust gas treatment or in the event of an emergency. In addition to the need to pay close attention to leakage accidents, these gases are extremely expensive and have problems with their purity, making them often unsuitable for use in mass production equipment.

Therefore, an object of the present invention is to provide a plasma CVD apparatus that can introduce a magnetic field circuit to form a high-density plasma region, enable high-speed film deposition, and obtain good film quality and uniform film thickness distribution. It's about doing.

[Means for solving problems]

In order to achieve the above objects, according to the present invention.

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 electrodes installed in a vacuum container and turning the reactant gas introduced into the vacuum container into plasma. The plasma CVD apparatus is characterized in that a device for forming a closed-loop magnetic field is provided on the electrode to which a high-frequency voltage is applied.

The substrate may be positioned at a distance from the high density plasma region formed by the magnetic field formed by the closed loop magnetic field forming device.

According to another feature of the present invention, the present plasma CvD apparatus includes scanning a magnetic field formed by a closed-loop magnetic field forming device to scan a high-density plasma region formed by the magnetic field on the substrate. A scanning device is provided.

Furthermore, according to yet another feature of the invention, the plasma O
The VD apparatus is provided with a scanning device that scans the substrate with respect to the high-density plasma region.

[For production]

With this configuration, in the device of the present invention, the plasma is concentrated by the closed-loop magnetic field generated by the magnetic field forming device to form a high-density plasma region,
This greatly accelerates the decomposition of the source gas, resulting in a deposition rate of /OA/sec or higher. On the other hand, by promoting the decomposition of the 5 reaction gases, the efficiency of using the raw material gases is also greatly improved.

In addition, the substrate may be positioned at a distance from the high-density plasma region formed by the magnetic field formed by a closed-loop magnetic field forming device, or a scanning device may be provided to scan the magnetic field so that the substrate is formed by the magnetic field. A uniform film thickness distribution can be obtained by scanning a high-density plasma region over the substrate or by scanning the substrate with respect to the high-density plasma region.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 schematically shows an embodiment of a plasma CVD apparatus according to the present invention, and %l is a vacuum chamber equipped with a reaction gas introduction mechanism and an exhaust mechanism. Inside the vacuum chamber is a high frequency application electrode and a ground electrode! are arranged facing each other, and the high frequency application electrode≠ is connected to the high frequency power source 7 via the matching circuit 6.
It is connected to the.

As shown in the figure, a magnet t that generates a closed-loop magnetic field in the radial direction of the electrode is installed inside the high-frequency application electrode μ, and a magnetic plate forming a magnetic circuit is attached to the back side of the magnet r. These components constitute a closed-loop magnetic field forming device.

The ground electrode j constitutes a support device that supports the substrate 10. Further, a heating mechanism /I for heating the attached substrate 10 to a desired temperature is incorporated in the ground electrode 5, and this heating mechanism // is energized by a heating power source 12. Board IO
Attachment and removal may be performed by any suitable means. Furthermore, in the illustrated embodiment, in order to improve the film thickness distribution on the substrate 10, the driving mechanism/3 The position of the substrate 10 can be moved by.

In the operation of the illustrated apparatus configured as described above, first, a reactive gas is introduced into the vacuum chamber by the reactive gas introducing mechanism λ, and the desired gas composition, gas flow rate, and After that, a high frequency voltage is applied to the high frequency application electrode≠ to generate a glow discharge between the high frequency application electrode≠ and the ground electrode j. At this time, the electrons generated in the plasma are captured by the closed loop magnetic field arranged in the radial direction of the high frequency application electrode formed by the magnet t, and the electron density in this part becomes extremely high. As a result, a high-density plasma region is formed as shown in the figure, promoting the decomposition of the reactant gas, /OA/
Film deposition can be performed at higher speeds than see. In this case, since the power density is comparable to that of a normal plasma CVD apparatus, the energy of ions incident on the film does not increase. In addition, because the electron density is extremely high, the growth of growth nuclei generated in the gas phase due to reactions between active species is suppressed due to electron bombardment, resulting in non-uniformity in the structure within the film. There is no deterioration in film quality.

FIG. 2 shows an example of film formation performed using the apparatus shown in FIG. 1, in comparison with the film formation speed according to the conventional method. As can be seen from this graph, it is recognized that a high film formation rate can be obtained in the illustrated apparatus despite the low power density.

Figure 3 ~ No. 3! The figures show other different embodiments of the present invention in which a uniform film thickness distribution is achieved using various scanning devices, and in these drawings, parts corresponding to those in FIG. 1 are designated by the same reference numerals.

In the embodiment shown in FIG. 3, the high frequency application electrode is rotated by a drive device 14A.

In the embodiment shown in Figure 1, the drive device/! The structure is such that only the magnet t within the high-frequency application electrode μ is rotated by the high-frequency application electrode μ.

Further, in the embodiment shown in FIG. 5, the substrate io is rotated together with the ground electrode j by a driving device/B.

In this way, as a means to improve the film thickness distribution on the substrate, a closed-loop magnetic field formed by a magnet is scanned over the substrate, but conversely, a scanning device is provided that scans the substrate against the magnetic field. A high density plasma region formed by the magnetic field may be scanned over the substrate.

〔Effect of the invention〕

As described above, according to the present invention, a closed-loop magnetic field generated by a magnetic field forming device concentrates plasma to form a high-density plasma region, which greatly accelerates the decomposition of source gas. Since it is configured like this,
High-speed film formation is possible without using dangerous and expensive gases, and raw material gas utilization efficiency is also improved. Further, since a large amount of electric power is not required, deterioration in film quality can be prevented and the film thickness distribution can be made uniform. Therefore, the productivity of the plasma CVD apparatus can be greatly improved.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a plasma CVD apparatus according to an embodiment of the present invention, Fig. 2 is a graph showing an example of film formation performed using the apparatus shown in Fig. 1, and Figs. This is a schematic diagram showing another different embodiment of the invention, in which 1: odor chamber% reaction gas introduction mechanism, 3: exhaust mechanism, ≠: high frequency application electrode,
j: Ground electrode, B: Matching circuit, 7: High frequency power supply,
t: magnet, ri: magnetic plate, 10: substrate, //: heating mechanism,
/2: Heating power supply % /3: Rotating mechanism, /≠, l, 1
6: Drive device.

Claims (1)

[Claims] 1. A high-frequency voltage is applied to a parallel plate type electrode provided in a vacuum container, and the reaction gas introduced into the vacuum container is turned into plasma, thereby being attached to a support device equipped with a heating mechanism. A plasma CVD apparatus for forming a thin film on a substrate, characterized in that a device for forming a closed-loop magnetic field is provided on an electrode to which a high-frequency voltage is applied. 2. The plasma C according to claim 1, wherein the substrate is positioned at a distance from a high-density plasma region formed by a magnetic field formed by a closed-loop magnetic field forming device.
VD device. 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 electrodes installed in a vacuum container and turning the reactive gas introduced into the vacuum container into plasma. In the plasma CVD apparatus, a device for forming a closed-loop magnetic field is provided on an electrode to which a high-frequency voltage is applied, and the magnetic field is scanned to generate a high-density plasma region formed by the magnetic field on the substrate. 1. A plasma CVD apparatus characterized by being provided with a scanning device that performs scanning. 4. 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 electrodes installed in a vacuum container and turning the reactive gas introduced into the vacuum container into plasma. In the plasma CVD apparatus, a device for forming a closed-loop magnetic field is provided on an electrode to which a high-frequency voltage is applied, and the substrate is scanned with respect to a high-density plasma region formed by the magnetic field. A plasma CVD apparatus characterized by being provided with a scanning device.