JPS63260031A - Plasma reaction treatment device - Google Patents

Abstract

PURPOSE:To speed up reaction and remove a deteriorated organic film by using an upper part in a chamber as a principal region for producing plasma and using a lower part in the chamber as a treating region of substances to be treated such as a wafer and the like, thereby sucking downward the plasma produced by the above region for producing plasma through an exhaust port. CONSTITUTION:This device makes a bell-jar type chamber 3 have a bending part 4 on its upper part and a conductor cylindrical upper electrode 6 connected to a high frequency oscillator 5 is wound around its bending part and the inside of the bending part 4 is used as a principal region 7 for producing plasma. On the other hand, a lower electrode 11 that is grounded is installed at a rod upper end of a cylinder unit 9. While a mixed gas comprising 5 vol% of C2F6 and O2 of the remainder is introduced from a gas introducing port 24 into the principal region 7 for producing plasma, the evacuation of air contents from the exhaust port 25 allows the inside of the chamber 3 to be 1 Torr under reduced pressure. Such a process also permits the gas which is introduced by impressing high frequency waves to the upper electrode 6 to be in a state of the plasma and its gas to flow down toward the exhaust port 25. Thus, an organic film which is formed on a wafer W surface is chemically removed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The undeveloped ψ1 relates to a plasma reaction processing apparatus used for etching semiconductor wafers, removing organic films formed on wafer surfaces, and the like.

(Prior art) When manufacturing semiconductor devices, wafers (
The process of peeling off the organic film (photoresist) formed on the semiconductor substrate 1 or etching the wafer is an essential process. This process is usually carried out in two ways: a wet method using chemicals and a dry method using plasma.
There are seeds. By the way, the latter method is currently the mainstream in terms of work method, safety, etc. In this dry method using plasma, a working gas is excited by high-frequency discharge, the wafer is exposed to the generated plasma, and a chemical reaction with the radicals in the plasma converts the desired part of the wafer into a gaseous reactant. As a device for such processing, there is a device in which a plate-shaped upper electrode and a lower electrode are arranged close to each other in parallel in a chamber (Japanese Unexamined Patent Publication No. 113164/1982). and a device in which an electrode connected to a high-frequency power source and a grounded electrode are arranged opposite to each other on the upper part of the chamber (Special Publication No. 54
-32740), and.

In the former device, the space between the upper and lower electrodes becomes a plasma generation section, and the wafer is processed in this plasma generation section.
In the latter apparatus, the upper part of the chamber surrounded by a pair of electrodes serves as a plasma generation section, and the lower part of the chamber serves as a reaction processing section for processing the wafer with radicals from the plasma generation section.

(Problems to be Solved by the Invention) Among the above-mentioned apparatuses, in those in which the wafer is placed in a plasma generating section for processing, the wafer is damaged by ions and charged particles present in the plasma. .

In addition, in an apparatus in which the chamber is separated into a plasma generation section and a reaction processing section, the amount of radicals that reach the wafer surface is small, making it suitable for use as a masking device during ion implantation of high cullet, bydose, etc. v1 membrane cannot be removed.

Further, in any of the apparatuses, if there is no means for controlling the temperature of the wafer support table, the reaction treatment temperature of the wafer may exceed the range of 100° C. to 200”O, resulting in defective products.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a cylindrical upper electrode connected to a high frequency power source at the upper part of the chamber, and a grounded lower part at the bottom of the chamber spaced apart from the upper electrode. By providing an electrode, the lower part of the chamber was used as a main plasma generation area, and the plasma generated in this main generation area was sucked downward through an exhaust port, so that the lower part of the chamber was used as a processing area for objects to be processed such as wafers.

(Function) Since the object to be processed is processed at a position away from the area where plasma is mainly generated, there is less damage from ions or charged particles, and because the processing area is the space between the upper electrode and the lower electrode. Radicals involved in the reaction sufficiently reach the object to be treated.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 is an overall vertical sectional view of a processing apparatus to which the plasma reaction processing apparatus according to the present invention is applied, and FIG. 2 is a plan sectional view of the same processing apparatus. A plasma reaction processing section N(2) according to the present invention is provided. This plasma reaction processing device (2) is a bell jar type (
The upper part of the bell-shaped chamber (3) is a bent part (0), and a cylindrical upper electrode (6) made of a conductor connected to a high-frequency oscillator (5) is wound around this bent part (4). The inside of the bent portion (4) is the main plasma generation region (7).

On the other hand, vertical cylinder units (9) and (10) are fixed on the support plate (8) in the device body (1), and the lower electrode (grounded) is attached to the upper end of the rod of the cylinder unit (9). 11) is attached, and the lower electrode (11)
A sub-table (12) is attached to the upper end of the cylinder unit (lO) that penetrates through the center of the cylinder unit (lO), and these lower electrodes (
11) and the sub-table (12) there is a cooling water passage (l
la) and (12a) are drilled. Therefore, by operating the cylinder (22) (8) (to), the lower electrode (11) and the sub-table (12) move up and down independently, and when the lower electrode (11) descends, is the main body (1)
located below the conveyor belt (13) disposed inside,
When it rises, the opening (14) formed in the main body (1) is closed, and the bottom of the chamber (3) is hermetically closed. And the opening (14) is closed by the lower electrode (11)! E
At the bottom of the chamber (3) there is a reaction processing area (1) into which the plasma (radicals) from the main plasma generation area flows.
5) is formed.

Also, on both sides of the main body (1), there are lifting members (1B), (17
) are placed. These lifting members (lO), (17)
consists of four pillars, between which cassettes (18) and (111) holding a plurality of wafers can be attached. Cassette) (18), (19)
A slit is formed on the opposing surfaces of a pair of plates, and by inserting the edge of the wafer (-) into this slit, multiple wafers (-) are held apart in the vertical direction. .

Further, the conveyor belt (13
) are placed at the same height as the conveyor belts (20) and (21), and the wafers in the cassette (18) are passed through the opening (22) onto the conveyor belt (13), and , transport bell) (13) Open the upper wafer (W) (23)
The receiver is passed into the cassette (1θ) through the cassette.

A process of removing an organic film formed on the surface of a wafer using the plasma reaction processing apparatus having the above configuration will be described below.

First, as shown in Fig. 3, the lifting member (16) is lowered, and with the lower electrode (11) positioned below the transport bell (13), the lowermost wafer in the cassette (18) is (The straw conveyor belt (20)
13) Pass the receiver on top and drive the conveyor belt (13).

The wafer (W) is transported onto the sub-table (12). Next, operate the cylinder (22) (10) to raise the sub-table (12), pick up the wafer (butt) on the conveyor belt (13), and then move the lower electrode (11) to the lower electrode (11).
The transport bells (13) are separated from each other and opened to the extent that the lower electrodes (11) can be lowered, and the cylinder unit (8) is actuated to raise the lower electrode (11), which is fitted into the opening (14) airtight and opened. The lower electrode (11) faces into the reaction treatment area (15) in (3).

After this, 02F6 was added to the main plasma generation region (7).
A mixed gas with volume% 02 as the balance is introduced into the gas inlet (24
) and reduce the pressure from the exhaust port (25) connected to a vacuum pump (not shown) to the chamber (3).
A high frequency of 250111 Torr is applied to the upper electrode (6) to turn the introduced gas into plasma, which flows down toward the exhaust port (25). Then, the organic film formed on the surface of the wafer (W) is chemically removed by reaction with the activated reaction gas (mixed gas).

Thereafter, the lower electrode (11) is positioned below the conveyor belt (13) by driving in the opposite direction to the above, and the sub-table (12) is lowered to remove the wafer (from which the organic film has been removed).
Transfer the WI transport belt (13) onto the transport belt (13).
The wafer (W) is transferred onto the conveyor belt (21) by the drive of step 3), and the wafer (W) is stored in the cassette (19) by the drive of the conveyor belt (21). By repeating this process, all the wafers (W) in one cassette (18) are processed and stored in the other cassette (19).

FIG. 4 is a diagram showing a plasma reactor according to another embodiment, and in this embodiment, the chamber (3) is connected to the small diameter section (
3a) and a large diameter part (3b), and the cylindrical upper electrode (8) around the small diameter part (3a) is divided into two semi-cylindrical electrodes (8a) and (8b). , connect only one electrode (6a) to a high frequency power source.

It is possible to select whether the other electrode (8b) is connected to a high frequency power source or grounded via a switch (2B).

With this configuration, 1. For example, in the initial stage of removing an organic film used as a mask for ion implantation, the electrode (Eta)
) and (eb) are both connected to a high frequency electrode to remove the altered organic film. Once the cloth a film has been removed to some extent, the electrode (6b) is grounded and only the upper part of the chamber (3) is exposed to plasma. The remaining organic film can be removed efficiently.

(Effects of the Invention) As explained above, according to the present invention, the upper electrode is disposed at the upper part of the chamber, and the lower electrode is disposed at the bottom of the chamber separated from the upper electrode, so that the upper part of the chamber becomes the main plasma generation area. Therefore, compared to conventional devices in which the upper and lower electrodes are flat and arranged close to each other in parallel, the object to be processed is not damaged by ions or charged particles, and plasma Since the plasma generated in the main generation area is directly sucked into the reaction processing area below, in the conventional device, a pair of electrodes was installed at the top of the chamber to clearly separate the plasma generation area and the reaction processing area. The reaction rate is faster than that of conventional methods, and it is also possible to remove degraded organic films.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a plasma reaction processing apparatus according to the present invention, FIG. 2 is a plan sectional view of the same apparatus, and FIG. 3 is a longitudinal sectional view similar to FIG. FIG. 4 is a diagram showing another embodiment. In one drawing, (1) is the device main body, (2) is the plasma processing device, (3) is the chamber, (6) is the upper electrode, (7)
is the main plasma generation region, and (11) is the lower electrode. (9), (10) are cylinder units, (13), (2
0), (21) are a conveyor belt, (15) is a reaction processing area, (25) is an exhaust port, and (W) is a wafer.

Claims (3)

[Claims] (1) A cylindrical upper electrode to which a high frequency is applied is arranged at the top of a bell jar-shaped chamber, and the upper part of the chamber is the main plasma generation area, and a grounded lower electrode and exhaust air are placed at the bottom of the chamber, which is spaced from the upper electrode. A plasma reaction processing apparatus characterized in that a lower part of the chamber is used as a processing region for an object to be processed by sucking plasma generated in the main plasma generation region downward through the exhaust port. (2) The plasma reaction processing apparatus according to claim 1, wherein a passage for a cooling medium is formed in the lower electrode. (3) A patent characterized in that the upper electrode is divided into semi-cylindrical shapes, one of the divided upper electrodes is connected to a high frequency power source, and the other upper electrode is selectively connected to ground and the high frequency power source. A plasma reaction processing apparatus according to claim 1.