JPH0243962A - Dust collector for vacuum treatment device - Google Patents

Abstract

PURPOSE:To perform dust collection at high efficiencies under high vacuum by providing near a transfer section in a vacuum chamber a dust collecting electrode for applying positive D.C. high voltage not so high enough as to cause an electric discharge and also providing a source of electron beam for applying electron beams through the space near the surface of the dust collecting electrode. CONSTITUTION:Near a transfer section 2 in a vacuum chamber of a vacuum treatment device wherein such a treatment as membrane accumulation, etching, surface cleaning, etc., is applied to the surface of a substrate 5 under vacuum, a dust collecting electrode 31 for applying a high positive D.C. voltage, which is not so high as to cause an electric discharge, is provided, while a source 21 of electron beam which applies electron beam through the space near the surface of the dust collecting electrode 31 is provided. As a result, by the addition of a simple device, dust collection can be conducted at high efficiencies under vacuum, practically without exerting any influence on the transfer of the substrate.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a vacuum processing apparatus that performs processes such as film deposition, etching, and surface cleaning on the surface of a substrate in a vacuum. The present invention relates to a dust collector that effectively collects dust.

(Prior Art) Conventionally, in semiconductor manufacturing equipment, dust inside the equipment has been a major cause of lowering the yield rate of products.For example, in high-vacuum, high-precision equipment such as molecular beam crystal growth equipment, Dust attached to the surface of the substrate affects the crystallinity of the produced film, causing crystal defects. This dust is often generated from a movable mechanism such as a substrate transport section, that is, a portion that undergoes deformation, sliding, and attachment/detachment.

Conventionally, the transfer section was placed under a high vacuum to speed up the fall of dust, the surface to be processed of the substrate was carried vertically or downwards to prevent dust from adhering to the substrate, and the sliding method using magnetic levitation was used. Efforts have been made to minimize the generation of dust from the drive unit by using a transport mechanism with no moving parts.

In addition, a structure has been developed in which the transport drive section is covered with a metal plate and a high voltage is applied between the metal plate and the drive section to collect dust using electrostatic force. (For example, JP-A-62-1127
(Publication No. 90 "Retention membrane treatment device with dust collector") (Problems to be solved by the invention) However, of the above conventional measures, the former lacks the power to actively remove dust, and the driving part of the latter is Even the structure covered with insulating dust was not very effective against insulating dust. For this reason, in the end, dust collection was left half-hearted and almost abandoned.

However, in recent VLSIs, the wiring width has become finer and the density has increased, and the yield of products tends to deteriorate significantly due to the presence of minute dust, making it an absolute imperative to achieve a high degree of dust-free production.

(Objective of the Invention) The present invention solves the above-mentioned problems and performs dust collection under high vacuum with high efficiency without using complicated means and with almost no effect on substrate transportation. The purpose is to provide a new dust collector for vacuum processing equipment that can perform

(Means for Solving the Problems) The present invention provides a dust collecting electrode that applies a positive high voltage of direct current that does not cause discharge near the conveying section in the vacuum chamber, and The above object is achieved by providing an electron beam R that irradiates the nearby space with an electron beam.

Dust in the vacuum chamber and dust generated in the transport section are negatively charged when irradiated with electron beams, and are strongly electrostatically collected by the strong electric field of the dust collection electrode to which a high positive voltage is applied. .

(Example) The present invention will be explained in detail below using the figures.

FIG. 1 shows a cross-sectional view of an embodiment of the present invention, in which a movable mechanism 2 for transporting a silicon substrate 5, which is a substrate to be processed, is shown in an interior 1a of a vacuum chamber 1 (1b on the atmospheric side). A rotating shaft 201 (bearing 211) driven by a rotational drive device (not shown)
．． The rotation of the rotating shaft 202 (supported by a bearing 213) is transmitted to the rotating shaft 202 (supported by a bearing 213) by pulleys 221, 222 and belt 231, and the rotation of the shaft is transmitted to the pulley 222, 223 of this shaft.
The silicon substrate 5 placed on two belts 232 and 233 is conveyed in a direction perpendicular to the plane of the paper, but there are sliding and attachment/detachment movements between each shaft, bearing, each heald, and between the heddle and the substrate. , generates extremely fine dust due to wear. Furthermore, deformation of various parts, especially curvature of the belt, also becomes a source of fine dust. As mentioned above, in the past, methods have been adopted to prevent the generation of fine dust by reducing the number of movable mechanism parts or by covering the movable mechanism with a dust collecting electrode to which a high voltage is applied.

In the embodiment, the following dust collecting means that utilizes electrostatic force is added to prepare for these dusts.

A conductive dust collection electrode 31 with an inverted cross-section is installed on the upper side of the movable mechanism 2 along a length of about 30 cm with an insulator 32 on the wall of the vacuum chamber 1. A positive DC high voltage is applied between the dust collection electrode 31 and the ground from a dust collection DC power supply 30. Vacuum chamber 1 is at ground potential.

On the opposite side of the dust collection electrode 310 across the space above the substrate 5 being transported, a filament 21 heated to an incandescent state by a current from a low-voltage DC power supply 20 (also at ground potential) on the atmospheric side is an insulating material. It is introduced into the vacuum chamber 1 via 22, and this serves as an electron beam source.

Dust floating in the vacuum chamber 1 and fine dust generated in the movable mechanism 2 and raised above are irradiated with the electron beam generated from the electron beam source 21 and are negatively charged and have a high positive potential. The dust is attracted to the dust collecting electrode 31 by electrostatic force and adheres thereto. Note that all conductive members of the movable mechanism 2 are treated to have the same potential as the vacuum chamber 1.

Now, by applying a positive DC voltage V31 from a DC high-voltage voltage R31 to the dust collecting electrode 30 and performing experiments under various conditions, the following results were obtained, and it was confirmed that the present invention is very effective in collecting dust. confirmed.

Apply O■ and +5kV as VB2, and filament 2
Pass current through 1 to make it glow, or cut off the current,
Actually, when a 4-inch silicon substrate 5 was transported back and forth by the length of the dust collection electrode 31 perpendicular to the plane of the paper in FIG.
The measurements were taken with a dust counter (detects by using the scattering of laser light by dust) that can measure up to

The results shown in Table 1 were obtained.

Table 1 The degree of vacuum at this time was on the order of 10-9 Torr.

The above was a case where the electrode was a bent plate, but as a result of experiments with various electrode shapes, the best results were obtained when the electrode was provided with multiple needle-like protrusions in the direction of the filament. . This is thought to be because the needle-shaped electrode provides the strongest electric field, increasing the dust collection force.

(Effects of the Invention) According to the collecting device of the present invention, with the addition of a simple device, dust collection under high vacuum can be performed with high efficiency, with almost no effect on substrate transport.

From Table 1, it can be seen that the dust in the transfer chamber is already considerably reduced just by the presence of a dust collection electrode to which a high voltage is applied, but that this alone is not enough to reduce the dust, and furthermore, when operating the electron beam source, it is necessary to It is clear that it can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a substrate transport section according to an embodiment of the present invention. 1... Vacuum chamber, 2... Movable transport mechanism, 30...
High voltage power supply 2.31... Dust collection electrode, 5... Substrate, 2
0...Low voltage DC power supply, 21...Filament (electron beam source).

Claims (2)

[Claims] (1) Dust collection by applying a high DC positive voltage that does not cause an electric discharge near the vacuum chamber transfer section of a vacuum processing equipment that performs processes such as film deposition, etching, and surface cleaning on the surface of a substrate in a vacuum. 1. A dust collector for a vacuum processing apparatus, comprising an electrode and an electron beam source for irradiating a space near the surface of the dust collecting electrode with an electron beam. (2) A dust collecting device for a vacuum processing apparatus according to claim 1, wherein the dust collecting electrode includes a needle-like protrusion.