JPS6063919A - Surface treating device - Google Patents

Abstract

PURPOSE:To reduce impact damages of a substrate and to enable a high-quality treatment thereof by exposing the substrate to be treated to the floating electric potential state in the discharge plasma. CONSTITUTION:A cylindrical substrate 1a is fixed to a container 8 through an insulator 10 but not to one of the electrodes. A cylindrical electrode 80 is provided to be connected to the container 8, and a heater 5 is wound around the electrode, whereby a typical hollow-cathode-discharge-type device is provided. A floating potential shield plate 29 inhibits electric discharge from being generated between the upper end of the electrode 2 and the upper interior surface of the container 8 so that the electric discharge is uniformed. Since the electric potential of the substrate is conformed to the potential of the plasma around the substrate, the charged particles in the plasma are not accelerated and impact damages can be reduced. Further, no shadows or barriers are made around the substrate 1a, which assures a uniform surface treatment for the whole peripheral surface of an either conductor or insulator substrate 1a having an optional shape without any rotary or reciprocal movement of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a gas discharge device for decomposing and activating a predetermined gas by electrical discharge, and performing solid surface treatments such as forming a thin film on the surface of a substrate, cleaning and surface modification. Regarding improvements.

This will be explained below using figures.

Figure 1 shows two etchings of film deposited on the same cylindrical substrate and cleaning.

1 is a conceptual diagram of a conventional apparatus used for processing such as surface modification (represented by film deposition below). The substrate 1 to be processed is grounded and electrically connected to a vacuum container 8, and a cylindrical high voltage applying electrode 2 is arranged on the outside thereof. A predetermined gas is introduced into the reaction gas introduction system 3 and exhausted through the exhaust system 4.

Set the inside of the reaction chamber to a predetermined pressure.

The substrate 1 to be processed is heated by a heating heater 5 using a heating power source 7. Power supply 6, 9DC, AC to electrodes 1 and 2
Alternatively, when a high RF voltage is applied, a discharge occurs between the two electrodes, the introduced gas is decomposed and activated, and is deposited on the substrate 1.

At this time, since the substrate 1 is one of the electrodes, charged particles violently enter and exit the surface of the substrate 1, and the substrate is thereby damaged by impact. In order to reduce this impact damage, it is sufficient to reduce the applied power, particularly the voltage, but in order to increase the film formation rate, the applied power must be increased. Damage and film formation rate have a mutually contradictory relationship.

In addition, in order to obtain uniform film quality and thickness, it is necessary to rotate or reciprocate the substrate 1, which makes it difficult to apply power to the substrate, measure the temperature of the substrate, etc., and makes the device unnecessarily complicated and expensive. Ta.

The present invention aims to solve this problem. That is.

The purpose of this invention is to provide a device that can perform damage-free surface treatment at high speed.

The present invention also includes: The object of the present invention is to provide a new apparatus capable of uniformly and high-quality surface treatment on a substrate, regardless of whether the object to be treated is a conductor or an insulator, and regardless of the shape of the substrate.

FIG. 2 is a diagram similar to the former embodiment of the present invention.

The same reference numerals in the figures indicate the same members. The difference between FIG. 2 and FIG. 1 is that the cylindrical substrate 1a is no longer one of the electrodes, υ, and the insulator 1 is
A cylindrical electrode 80 is provided which is fixed to the container 8 via a cylindrical electrode 80 and connected to the container 8 via a cylindrical electrode 80, and the heater 5 is wound around the cylindrical electrode 80.

Therefore, the device is a typical hollow cathode discharge type device. The newly installed floating potential shielding plate 29 serves to suppress the generation of electrical charges between the upper end of the electrode 2 and the upper inner surface of the container 8, and to make the discharge uniform.

The potential of the substrate 1a is such that it floats in the discharge plasma. In this case, since the potential of the substrate collector follows the potential of the surrounding plasma, there is no acceleration of charged particles in the plasma, and impact damage is greatly reduced.

Further, the substrate is rotated so that no potential shadow or barrier is generated around the substrate 1a.

Even without reciprocation, the effect of uniform surface treatment on the entire periphery of a conductor or insulator substrate 1a having an arbitrary shape is produced. That is, the above-mentioned problems are solved all at once. FIG. 4 shows an infrared absorption spectrum of a hydrogenated amorphous silicon film formed on a substrate la using this apparatus. The substrate temperature is 250
°C, and silane and disilane are used as gases. SiH
It can be seen that a high quality hydrogenated amorphous silicon film V with fewer 2 bonds can be obtained. The thickness distribution of this film was sufficiently uniform, the insulation resistance was high, and its spatial variation was extremely small compared to the conventional film. Compared to conventional equipment, the film formation rate is more than 10 times faster by applying about three times as much power. Note that by installing the magnetic field generating coil 30 outside the vacuum vessel 8, the plasma density can be further increased.

FIG. 3 shows another embodiment of the present invention, in which thin disk-shaped substrates 1b, lc, ld, . . . are insulating support columns 9a, 9b, . The trays 9 are piled up at appropriate intervals 12 using grooves 11, so that the reaction gas and plasma can freely exit and enter within these intervals 12. A heating heater 5 is arranged outside the ground electrode 苧O. In this way, the temperature distribution within the cylinder 80 becomes substantially uniform. Cylindrical electrode 2 and vacuum container 80
When a high voltage is applied between.

Hollow cathode discharge occurs in the internal space of the cylindrical electrode 2.

The substrates 1b and lc are exposed to the discharge-decomposed plasma.

... is surface treated. When the distance 12 is appropriately sized, the surface treatment is carried out simultaneously on both sides of the substrate.

and progress evenly. The substrates 1b, lc in this case.

. . . may be either a conductor or an insulator.

Although the above example uses a cylindrical electrode, the present invention can also be effectively implemented in the case of a parallel plate electrode.

The apparatus of the present invention has the above structure, and is characterized in that the substrate to be processed is placed in a state of floating potential in discharge plasma. As a result, impact damage to the substrate can be greatly reduced and high-quality processing can be performed. Even when the substrate to be processed has a complex shape with uneven surfaces, the surface processing is highly uniform (
As shown in the embodiment shown in FIG. Moreover, high-speed processing with high power is possible.

The apparatus of the present invention greatly contributes to industries such as semiconductor manufacturing, and can be said to be an extremely useful invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a conventional cylindrical substrate film forming apparatus, and FIG. 2 shows an improved cylindrical substrate film forming apparatus of the present invention. FIG. 3 shows an apparatus used for surface treatment of film forming 1 on substrates other than 9 cylindrical substrates. FIG. 4 is an infrared absorption spectrum of a hydrogenated amorphous silicon film prepared by 1U using the apparatus shown in FIG. 1, la, lb, lc,...substrate 2...high voltage application electrode 3...reactive gas introduction system 4...exhaust device
5... Substrate heating heater 6... Electrode 7... Heating power source 8... Vacuum container 8o... Electrode connected to 8

Claims (2)

[Claims] (1) A device that separates and activates a predetermined gas in a discharge and performs a predetermined treatment on the surface of a substrate, in which the substrate is placed in a plasma space generated by the discharge with a floating substrate potential. Characteristic surface treatment equipment. (2) The surface treatment apparatus according to item 1, wherein the apparatus is a hollow cathode discharge type apparatus.