JPH05121334A - Plasma processing system - Google Patents

Abstract

PURPOSE:To obtain a plasma processing system which inhibits metal contamination and has better processing performance than conventional one. CONSTITUTION:A pipe connecting block 8, equipped on an upper electrode 2, is made of ceramics and shaped into a rectangular block. The block 8 is therein provided with a processing gas path 9, refrigerant inlet path 10, and refrigerant outlet path 11. These paths are, at their upper part, connected to a processing gas feed pipe 13, refrigerant inlet pipe 14 and refrigerant outlet pipe 15, respectively.

Description

Detailed Description of the Invention

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus.

[0003]

2. Description of the Related Art Conventionally, a plasma processing apparatus has been used in which plasma is generated by high-frequency power applied between electrodes and the plasma is used to process an object to be processed.
For example, in the manufacturing process of a semiconductor device, a dry etching apparatus that uses a plasma to etch a thin film formed on the surface of a semiconductor wafer, or a plasma CVD apparatus or a sputtering apparatus that forms a thin film using plasma is used. There is.

In such a conventional plasma processing apparatus, for example, a dry etching apparatus, parallel plate electrodes, for example, an upper electrode and a lower electrode are provided in a chamber, and a semiconductor wafer is placed on the lower electrode, for example. It is configured as follows. Then, a predetermined processing gas atmosphere is set in the chamber, and a predetermined high frequency power is supplied between the upper electrode and the lower electrode to generate plasma to remove the thin film formed on the surface of the semiconductor wafer by dry etching. To do.

[0005]

However, in recent years, semiconductor devices have been rapidly highly integrated, and their circuit patterns are becoming extremely fine. Therefore, in each processing step of the semiconductor device, dust-free and high-purification are required, and in the above plasma processing apparatus, for example, a dry etching apparatus, there is a big problem of so-called metal contamination caused by the action of plasma. It's becoming a problem.

The present invention has been made in response to such a conventional situation, and can suppress the occurrence of metal contamination.
An object of the present invention is to provide a plasma processing apparatus that can perform better processing than ever before.

[Constitution of Invention]

[0008]

That is, a plasma processing apparatus according to a first aspect of the present invention is a chamber for accommodating an object to be processed, an electrode provided in the chamber, to which a high frequency voltage is applied, and a predetermined chamber in the chamber. In a plasma processing apparatus comprising a processing gas supply piping system for supplying the processing gas of claim 1, at least a part of a contact portion of the processing gas supply piping system with the processing gas is made of a non-metallic member, To do.

According to a second aspect of the plasma processing apparatus of the present invention, a chamber for containing an object to be processed, an electrode provided in the chamber to which a high frequency voltage is applied, and a predetermined processing gas are supplied into the chamber. In a plasma processing apparatus including a processing gas supply piping system, at least a part of a bolt and a nut provided in the chamber is covered with a non-metallic cover.

[0010]

As a result of detailed investigation by the present inventors, in the conventional plasma processing apparatus, due to various conditions such as physical shape, processing gas, electric power, etc., not only in the processing chamber but also in the processing gas supply pipe made of metal. It was found that plasma was generated in the system and contributed to metal contamination. Therefore, in the plasma processing apparatus according to the first aspect, at least a part of the contact portion of the processing gas supply piping system with the processing gas is made of a non-metallic member, for example, high-purity ceramics, so that metal contamination occurs. Suppress.

Further, usually, metal bolts and nuts for fixing the respective constituent members are provided in the processing chamber. In the plasma processing apparatus according to claim 2, at least a part of these bolts and nuts is
By covering with a cover made of non-metal, for example, ceramics, generation of metal contamination is suppressed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a dry etching apparatus for dry etching a semiconductor wafer will be described below with reference to the drawings.

As shown in FIG. 1, the dry etching apparatus of this embodiment includes a cylindrical chamber 1 which can hermetically close the inside. The chamber 1 is mainly composed of a conductive material, such as aluminum (the surface of which is anodized), and the chamber 1 includes a disc-shaped upper electrode 2 and an upper electrode 2. The lower electrodes 3 are provided substantially in parallel so as to face each other.

Below the lower electrode 3, there is provided a bellows mechanism 4 as an airtight sealing mechanism which is expandable and contractable, and can be moved up and down by a drive mechanism (not shown) such as an air cylinder as shown by an arrow. It is configured. Further, the lower electrode 3 is configured such that the semiconductor wafer 5 can be placed on the upper surface thereof, and the semiconductor wafer 5 can be cooled to a desired temperature by a cooling mechanism (not shown) such as a coolant circulation mechanism. ..

On the other hand, the upper electrode 2 is made of a conductive material such as carbon, and is electrically connected to the constituent members of the chamber 1 by a cylindrical insulating member 6 made of an insulating material such as alumina ceramics. It is supported in an electrically insulated state. A plurality of process gas outflow holes 7 are formed in the upper electrode 2, and a pipe connection block 8 is connected to the upper portion of the upper electrode 2. The upper electrode 2 is also provided with a cooling mechanism (not shown) that circulates and cools the coolant.

As shown in FIG. 2, the pipe connection block 8 is formed in a rectangular block shape from an insulating member, in this embodiment, alumina ceramics having a purity of 99.5%, and the process gas flow passage 9 is formed inside. A coolant inlet channel 10 and a coolant outlet channel 11 are provided. Then, a processing gas supply pipe 13, a refrigerant inlet pipe 14, and a refrigerant outlet pipe 15 are connected to the upper portions of these flow paths via O-rings 12, respectively.

Further, at the lower end of the pipe connection block 8,
The flange portion 16 is provided so as to project laterally,
It is configured to be pressed and locked to the upper electrode 2 by a bolt or the like (not shown) via a connecting member 17 formed so as to fit into the flange portion 16. An O-ring 12 is inserted between the pipe connection block 8 and the upper electrode 2, and the process gas flow passage 9, the coolant inlet flow passage 10, and the coolant outlet flow passage 11 of the pipe connection block 8 are They are connected to a processing gas flow channel 18, a coolant inlet flow channel 19, and a coolant outlet flow channel 20, which are provided in the upper electrode 2, respectively.

The processing gas flow path 18 is connected to each processing gas outflow hole 7 of the upper electrode 2. Further, the coolant inlet flow channel 10 and the coolant outlet flow channel 11 are each connected to a coolant circulation flow channel (not shown) provided in the upper electrode 2.

Here, as described above, the pipe connection block 8 is made of alumina ceramics having a purity of 99.5%, but the processing gas channel 9 has a higher purity than other parts, for example, a purity of 99.9%. A cylindrical member 21 made of alumina ceramics is provided, and the inner wall of the processing gas channel 9 is made of alumina ceramics having a purity of 99.9%. This is to prevent undesired impurities from being generated as much as possible when plasma is generated in the processing gas flow path 9 as described above, and to prevent impurities from being mixed into the semiconductor wafer 5.

As described above, by using the pipe connection block 8 in which the processing gas supply pipe 13, the refrigerant inlet pipe 14, and the refrigerant outlet pipe 15 are integrally connected, the pipe connecting block 8 is detached from the upper electrode 2 at the time of maintenance. By doing so, it is possible to collectively attach and detach the pipes, and it is possible to shorten the maintenance time. Moreover, the upper electrode 2 and the pipes can be reliably insulated.

A power supply mechanism 22 is connected to the upper electrode 2 and the lower electrode 3 so that a high frequency power of a predetermined frequency, for example 13.56 MHz, can be supplied between the upper electrode 2 and the lower electrode 3. It is configured. Then, the processing gas (etching gas) supplied from the processing gas supply pipe 13
From the processing gas outflow hole 7 provided in the upper electrode 2 toward the semiconductor wafer 5 mounted on the lower electrode 3, and the gas is exhausted by the exhaust pipe 23 connected to the lower portion of the chamber 1. By doing so, the inside of the chamber 1 can be set to a predetermined gas atmosphere with a predetermined pressure.

Further, as shown in FIG. 3, in order to fix various members in the chamber 1, for example, to fix a plate member 31 to a base 30 made of ceramics, a metal bolt 32 (or Although nuts are provided, a cover 33 is provided above each of the bolts 32. As shown in FIG. 4, the cover 33 is made of a non-metallic material, for example, high-purity ceramics, and has a disc shape.
A circular hole 34 having a size of about m is provided. This circular hole 3
Reference numeral 4 is for facilitating removal of the cover 33 when operating the bolt 32 for maintenance or the like.

In the example shown in FIG. 3, since the bolts 32 are fixed to the base 30 made of ceramics, a metal cylindrical member 35 having a screw formed on the inner wall is preliminarily drilled in the base 30. It is adhered and fixed in the formed hole. By doing so, the bolt 32 can be more reliably fixed.

In the dry etching apparatus of this embodiment having the above structure, the semiconductor wafer 5 is loaded into the chamber 1 from the loading port (not shown) while the lower electrode 3 is lowered by the driving mechanism (not shown), and the lower electrode 3 is placed on the lower electrode 3. Place on.

After that, the lower electrode 3 is raised to set the distance between the upper electrode 2 and the lower electrode 3 to a predetermined distance.

After that, a predetermined processing gas (etching gas) is supplied from the processing gas supply pipe 13 to flow out from the processing gas outflow hole 7 toward the semiconductor wafer 5, and
Exhaust is performed from the exhaust pipe 23 to create a processing gas atmosphere of a predetermined pressure in the chamber 1, and at the same time, a predetermined frequency between the power supply mechanism 22 and the upper electrode 2 and the lower electrode 3,
For example, it supplies 13.56MHz high frequency power. Then, an electric discharge is generated between the upper electrode 2 and the lower electrode 3, the processing gas is turned into plasma, and the thin film formed on the surface of the semiconductor wafer 5 is dry-etched.

At this time, in this embodiment, as described above, the upper electrode 2 is connected via the pipe connecting block 8 forming the processing gas flow passage 9 by the cylindrical member 21 made of alumina ceramics having a purity of 99.9%. Process gas supply pipe 13
Since the above is connected, even if plasma is generated inside this, metal can be prevented from mixing into the semiconductor wafer 5, and the occurrence of metal contamination can be suppressed. Further, since the cover 33 is also provided all over the bolts 32 and the like provided in the chamber 1, it is also possible to prevent electric discharge from occurring in this portion, plasma from being generated, and metal contamination to occur. You can Therefore, it is possible to perform a good treatment with less metal contamination than in the conventional case.

During the above etching process, the upper electrode 2 is cooled by the refrigerant supplied to the cooling mechanism (not shown) through the refrigerant inlet pipe 14 and the refrigerant outlet pipe 15.
At the same time, the lower electrode 3 is cooled by a cooling mechanism (not shown).

[0029]

As described above, according to the plasma processing apparatus of the present invention, it is possible to suppress the generation of metal contamination, and it is possible to perform better processing than the conventional one.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a dry etching apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a main configuration of the dry etching apparatus of FIG.

FIG. 3 is a diagram showing another main configuration of the dry etching apparatus of FIG.

FIG. 4 is a diagram showing a configuration of a cover of FIG.

[Explanation of symbols]

 1 Chamber 2 Upper Electrode 3 Lower Electrode 5 Semiconductor Wafer 6 Insulating Member 7 Processing Gas Outflow Hole 8 Piping Connection Block 9 Processing Gas Flow Path 10 Refrigerant Inlet Flow Path 11 Refrigerant Outlet Flow Path 13 Processing Gas Supply Piping 14 Refrigerant Inlet Piping 15 Refrigerant Outlet piping 22 Power supply mechanism 23 Exhaust piping

Claims (2)

[Claims] 1. A plasma comprising a chamber for containing an object to be processed, an electrode provided in the chamber to which a high frequency voltage is applied, and a processing gas supply piping system for supplying a predetermined processing gas into the chamber. In the processing apparatus, at least a part of a contact portion of the processing gas supply piping system with the processing gas is formed of a non-metallic member. 2. A plasma comprising a chamber for containing an object to be processed, an electrode provided in the chamber to which a high frequency voltage is applied, and a processing gas supply piping system for supplying a predetermined processing gas into the chamber. A plasma processing apparatus, wherein at least a part of a bolt and a nut provided in the chamber is covered with a non-metallic cover.