JPH03219541A - Plasma processing device - Google Patents

Abstract

PURPOSE:To reduce corrosion damage and the pollution of a drawing electrode by forming a part of an electrode and a chamber wall which contact with a processing gas by use of conductive ceramics. CONSTITUTION:A magnetic field Bz, a filament power source Vf, a discharge power source Vd, and an accelerating power source Va are applied to each part, and Ar is introduced into an electron generating chamber 2 from an inlet port 5 to generate a plasma. The electrons are accelerated by an electric field and drawn into the chamber 9 through circles 6, 7, forming a plasma in the chamber 9. The electrons are accelerated by the voltage Va and drawn into an ion forming chamber 13 through a porous electrode 11. BF3 is introduced into the chamber 13 to form a concentrated plasma, which is drawn from the chamber 13 and utilized. As the wall of the chamber 13 is made of conductive ceramics, the damage of the wall can be reduced, resulting in a reduction in pollution of the electrode 11 by flying particles. Thus, maintenance frequency is reduced, and the working efficiency of the device is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Field of Application) The present invention relates to plasma processing apparatuses such as ion sources, CVD apparatuses, etching apparatuses, and X-ray sources.

(Prior Art) Generally, a plasma processing apparatus that electrically converts a predetermined gas into plasma and uses this plasma to perform a predetermined process on an object to be processed, such as an ion source, a CVD apparatus, an etching apparatus, an X-ray source, etc. Now, a voltage is applied between electrodes made of conductive metal, and a predetermined gas introduced between these electrodes is turned into plasma.

For example, in an ion source installed in an ion implanter or the like that implants ions as impurities into a semiconductor wafer or the like, such as an electron beam excited ion source, plasma is generated by discharge at a portion of a filament in a predetermined discharge gas atmosphere. Then, a predetermined raw material gas such as BF3 gas is introduced into a chamber (ion generation chamber) made of a conductive high melting point metal such as molybdenum, and the electrons in the plasma are extracted from the raw material gas. irradiation to generate ions from the source gas.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional plasma processing apparatus, such as an ion source, sputtering, etching, and other effects caused by plasma occur in a chamber (ion generation There was a problem in that the walls and the like of the chamber were scraped and damaged, and particles that were scraped and flew away adhered to undesired areas, such as ion extraction electrodes for extracting ions, and contaminated them.

Such problems arise when highly corrosive gases are used as processing gases,
For example, this is particularly noticeable when BF3 gas or the like is used. Further, for example, if the chamber is made of molybdenum and BF3 gas is used, an insulating substance such as molybdenum fluoride will adhere to the surface of the ion extraction electrode, and an insulating film will be formed.

Therefore, maintenance must be performed frequently to remove such insulating deposits, which causes a problem in that the operating rate of the device decreases and productivity deteriorates.

The present invention has been made in response to such conventional circumstances, and is capable of plasma processing that reduces maintenance frequency compared to the conventional method, improves the operating rate of the equipment, and improves productivity. The aim is to provide equipment.

[Structure of the Invention] (Means for Solving the Problems) That is, the plasma processing apparatus of the present invention electrically turns a predetermined processing gas into plasma, and uses this plasma to perform a predetermined treatment on an object to be processed. In plasma processing equipment,
The method is characterized in that at least a portion of the electrode that contacts the processing gas is made of conductive ceramics.

Further, an ion source according to claim 2 is an ion source that ionizes a predetermined processing gas introduced into a chamber by irradiating electrons to a predetermined processing gas introduced into the chamber, wherein the chamber is constructed of conductive ceramics. do.

Further, in the ion source according to claim 3, in the ion source that electrically ionizes a predetermined processing gas introduced into a chamber, at least a part of the electrode that comes into contact with the processing gas is made of conductive ceramics. It is characterized by

(Function) In the plasma processing apparatus of the present invention having the above configuration, at least a portion of the electrode that comes into contact with the processing gas is made of conductive ceramics.

That is, for example, in the ion source according to claim 2, the chamber is made of conductive ceramics, and for example, in the ion source according to claim 3, at least a part of the electrode provided in the chamber is made of conductive ceramics. It is configured.

Examples of conductive ceramics include rBN composite ECJ (trade name, manufactured by Denki Kagaku Kogyo Co., Ltd.), SiC, TiC5TiB2, Z r B 2 ,
Conductive ceramics containing TIN as a main component are suitable.

Therefore, even when a highly corrosive gas such as BF3 gas is used as the processing gas, damage to the electrode and chamber wall can be reduced compared to the conventional method, and damage to the ion extraction electrode, etc. caused by flying particles can be reduced. pollution can also be reduced.

Therefore, the frequency of maintenance can be reduced compared to the conventional method, and the operating rate of the apparatus can be improved, thereby improving productivity.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

First, an embodiment in which the present invention is applied to an electron beam excited ion source will be described.

As shown in FIG. 1, an electron generation chamber 2 formed in the shape of a rectangular container with each side having a length of, for example, several centimeters is provided above the ion source 1. The electron generating chamber 2 is made of a conductive high melting point side material, for example, conductive ceramics, and an insulating plate 3 is provided so as to close an opening provided on the lower side of the chamber. A U-shaped filament 4 made of, for example, tungsten is attached to this insulating plate 3.
It is supported at both ends and is provided so as to protrude into the electron generation chamber 2.

Further, a discharge gas inlet 5 for introducing a discharge gas, for example, argon (Ar) gas, is provided in the ceiling of the electron generation chamber 2. On the other hand, a circular hole 6 is provided at the bottom of the electron generation chamber 2 for extracting electrons from the plasma generated within the electron generation chamber 2.

Further, a plate-shaped insulating member 8 is provided at the lower part of the electron generating chamber 2 so as to form a bottleneck 7 continuous with the circular hole 6. A plasma cathode chamber 9 is provided which is made of a high melting point material such as conductive ceramics. Further, at the bottom of this plasma cathode chamber 9, a porous electrode 11 having a plurality of through holes 10 is provided.
is provided.

An ion generation chamber 13 is connected to the lower part of the porous electrode 11 via an insulating member 12. The ion generation chamber 13 is formed into a container shape from conductive ceramics as a conductive high melting point material, and the inside thereof is cylindrical with a diameter and height of about several centimeters. A bottom plate 15 is fixed to the bottom of the ion generation chamber 13 via an insulating member 14.

Furthermore, a processing gas inlet 1 is provided on the side surface of the ion generation chamber 13 through which a processing gas such as BF3'J for generating desired ions is introduced into the ion generation chamber 13.
6 is provided, and an ion extraction slit opening 17 is provided at a position facing the processing gas inlet 16.

The conductive ceramics constituting the ion generation chamber 13 (the same applies to the electron generation chamber 2 and the plasma cathode chamber 9) include, for example, rBN composite hE as described above.
cJ (product name, manufactured by Denki Kagaku Kogyo Co., Ltd.) or 5i
Conductive ceramics containing Cs TiC, TiB2, ZrB2 as a main component, etc. are suitable.

Further, the filament 4 is connected to a filament power source Vf, and is configured to be able to be heated by electricity. Further, a discharge power source Vd is connected to the electron generation chamber 2 via a resistor R, a discharge power source Vd is directly connected to the porous electrode 11, and a discharge power source Vd is connected between the porous electrode 11 and the ion generation chamber 13. The acceleration power supply V is arranged in series with
a is connected.

The ion source with the above configuration generates desired ions as follows.

That is, by a magnetic field generating means (not shown), the arrow B shown in the drawing is
A magnetic field is applied to guide the electrons in the electron extraction direction as shown in FIG.

Then, a discharge gas such as argon gas is introduced into the electron generation chamber 2 from the discharge gas inlet 5 at a predetermined flow rate of 0.4S, for example.
It is introduced by CCM, a discharge is generated, and plasma is generated. Then, the electrons in this plasma are accelerated by the electric field and are drawn out into the plasma cathode chamber 9 through the circular hole 6 and the bottleneck 7, forming plasma also in this plasma cathode chamber 9.

Then, electrons in the plasma in the plasma cathode chamber 9 are accelerated by the electron acceleration voltage Va, and are drawn out into the ion generation chamber 13 through the through holes 10 of the porous electrode 11.

On the other hand, a predetermined raw material gas such as BF3 gas is introduced in advance into the ion generation chamber 13 from the raw material gas inlet 16 at a predetermined flow rate of 0.93 CCM to create a predetermined raw material gas atmosphere. Therefore, the electrons flowing into the ion generation chamber 13 collide with the source gas molecules and generate dense plasma.

Then, these ions are extracted from the ion generation chamber 13 by an ion extraction electrode (not shown) and used for processing such as ion implantation into a semiconductor wafer.

At this time, in the ion generation chamber 13, a highly corrosive raw material gas such as BF3 gas is excited by being irradiated with electrons.
The resulting plasma becomes even more reactive. However, in the ion source of this embodiment, the ion generation chamber 3 is made of conductive ceramics as described above. For this reason,
Damage to the wall of the 0 ion generation chamber 13 can be reduced compared to the prior art, and contamination of the ion extraction electrode and the like by flying particles can also be reduced. Therefore, the frequency of maintenance can be reduced compared to the past, and the operating rate of the apparatus can be improved, leading to improved productivity.

In the above embodiment, the electron generation chamber 2 and the plasma cathode chamber 9 in addition to the ion generation chamber 13 are also constructed of conductive ceramics. However, the electron generation chamber 2 and the plasma cathode chamber 9 are not necessarily made of conductive ceramics. It does not need to be made of ceramics, and may be made of a conductive high melting point metal such as molybdenum.

Further, as shown in FIG. 2, for example, the ion generation chamber 13 and the like may have a two-layer structure of a metal such as molybdenum and conductive ceramics. That is, in the example shown in FIG. 2, the ion generation chamber] 3 has an outer cylinder 13a and a bottom plate 15a made of metal etc. provided on the outside, and an inner cylinder 13b (liner) and a bottom plate made of conductive ceramics provided on the inside. 1
Consists of 5b to 1.

Next, an embodiment in which the present invention is applied to a Freeman type ion source will be described with reference to FIG.

As shown in FIG. 3, the Freeman type ion source 20 is provided with a chamber 21 formed in a cylindrical shape.
Inside the chamber 21, a rod-shaped filament 23 whose both ends are supported by an insulating support part 22 is provided so as to pass through the chamber 21.

Further, an ion extraction opening 24 is provided in the front part of the chamber 21, and this ion extraction opening 24 is provided.
An ion extraction electrode 25 is provided facing the inner wall of the chamber 21. On the other hand, an opening 26 for introducing raw material gas is provided at the rear of the chamber 21. A liner 27 made of conductive ceramics is provided to cover the liner 2.
As mentioned above, 7 is, for example, "BN composite ECj (trade name, manufactured by Denki Kagaku Kogyo Co., Ltd.) or SiC.

Conductive 2 whose main components are Tic, TiB2, and ZrB2 It is made of ceramics, etc.

In the Freeman type ion source 20 having the above configuration, a filament power source (not shown) applies a predetermined voltage to the filament 23 to flow a current of, for example, 50 to 200 A, and a discharge power source 28 connects the filament 23 and the chamber 21, for example. A discharge voltage of about 80 to 100V is applied. Then, a predetermined raw material gas, for example, BF3 gas, is introduced into the chamber 21 from the raw material gas introduction opening 26,
A discharge is generated in the chamber 21 to ionize this source gas. These ions are extracted by the ion extraction opening 24 and the ion extraction electrode 25 and used for ion implantation into, for example, a semiconductor wafer.

In this embodiment described above, since the discharge voltage is applied by the discharge power supply 28 so that the chamber 21 becomes positive with respect to the filament 23, ions are attracted to the chamber 21, but as described above, the inner wall of the chamber 21 Since the liner 27 made of conductive ceramics is provided to cover the 3 chamber 21, it is possible to prevent the 3 chamber 21 from being damaged by the corrosive gas (BF3 gas), and the same effect as in the previous embodiment can be obtained. I can do it.

Note that in this example, the liner 2 made of conductive ceramics
Although the example in which the chamber 21 is provided has been described, the entire chamber 21 may be made of conductive ceramics.

Next, an embodiment in which the present invention is applied to a plasma etching apparatus will be described with reference to FIG.

As shown in FIG. 4, the plasma etching apparatus 30 is provided with a chamber 31 made of a material such as quartz and configured to be airtightly closed. Inside this chamber 31, an upper electrode 32 and a lower electrode 33 formed in a disk shape are provided so as to face each other in parallel. It is configured so that it can be placed. The upper electrode 32 and the lower electrode 33 are made of conductive ceramics similar to those in the embodiment described above, and are connected to a high frequency power source 35.

Further, a gas introduction pipe 36 and an exhaust pipe 37 are connected to the chamber 3, and the chamber 31 is configured to have a gas atmosphere at a predetermined pressure.

In this embodiment with the above configuration, the opening/closing mechanism (not shown) of the chamber 31 is opened, and the semiconductor wafer 3 is placed on the lower electrode 33.
4 is placed thereon, and then the opening/closing mechanism is closed to airtightly close the inside of the chamber 31.

Thereafter, the exhaust pipe 37 is evacuated, and a predetermined processing gas (etching gas) is introduced from the gas introduction pipe 36 to create a predetermined processing gas atmosphere at a predetermined pressure in the chamber 31.

Then, the high frequency power supply 35 connects the upper electrode 32 and the lower electrode 33 with a frequency of, for example, 2.45 GHz, 13.75 GHz.
Electric power of a predetermined frequency such as MHz or 435 KHz is applied to convert the processing gas into plasma and act on the semiconductor wafer 34, thereby performing an etching gas for the semiconductor wafer 34.

In this embodiment described above, the upper electrode 32 and the lower electrode 3
Since the upper electrode 32 and the lower electrode 33 are made of conductive ceramics similar to those in the above-mentioned embodiment, it is possible to prevent the upper electrode 32 and the lower electrode 33 from being damaged by ions and corrosive gas. Similar effects to those of the previous embodiment can be obtained.

Next, an embodiment in which the present invention is applied to a plasma CVD apparatus will be described with reference to FIG.

As shown in FIG. 5, the plasma CVD apparatus 40 is provided with a cylindrical chamber 41 made of a material such as quartz and configured to be airtightly closed. In this chamber 41, disc-shaped electrode plates 42 are arranged in a shelf-like manner, and every other electrode plate 42 is connected to the opposite polarity side of a high-frequency power source 43. These electrode plates 42 are made of conductive ceramics similar to those of the embodiments described above.

Further, a processing gas introduction section 44 and an exhaust section 45 are provided in the chamber 41 so as to face each other across the rows of electrode plates 42, and a predetermined processing gas ( CVD gas) can flow through it.

In this embodiment having the above-mentioned configuration, an object to be processed, such as a semiconductor wafer 46, is placed on each electrode plate 42 except for the uppermost electrode plate 42.
Place.

Then, while exhausting from the exhaust section 45, a predetermined processing gas is introduced from the processing gas introduction section 44, and each electrode plate 42
High frequency power is applied between each electrode plate 42 by a high frequency power source 43 while passing a predetermined processing gas between them. Then, the processing gas is turned into plasma by this high frequency power, and a CVD film is formed on each semiconductor wafer 46.

In this embodiment with the above-mentioned structure, each electrode plate 42 is made of the same conductive ceramics as in the above-mentioned embodiment, so that it is possible to prevent these electrode plates 42 from being damaged by ions. The same effects as in the embodiment can be obtained.

Note that the above embodiments include an embodiment in which the present invention is applied to an electron beam excited ion source, an embodiment in which the present invention is applied to a Freeman type ion source, an embodiment in which the present invention is applied to a plasma etching apparatus,
Although an embodiment has been described in which the present invention is applied to a plasma CVD apparatus 7, the present invention is not limited to such an embodiment, and can be applied to any apparatus that uses plasma, such as an X-ray source. I can do it.

[Effects of the Invention] As explained above, according to the plasma processing apparatus of the present invention, damage caused by ions can be reduced compared to the conventional method.
It is possible to reduce maintenance frequency, improve the operating rate of the device, and directly increase productivity.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an electron beam excited ion source according to an embodiment of the present invention, FIG. 2 is a diagram showing a configuration of a modified example of the electron beam excited ion source of FIG. FIG. 4 is a diagram showing the configuration of a Freeman type ion source according to an embodiment of the present invention, FIG. 4 is a diagram showing the configuration of a plasma etching apparatus according to an embodiment of the present invention, and FIG. 5 is a diagram showing a plasma CVD apparatus according to an embodiment of the present invention. FIG. 1... Ion source, 2... Electron generation chamber, 3...
...Insulation 8 Edge plate, 4...Filament, 5...Discharge gas inlet, 6...Circular hole, 7...
Bottle, 8...Insulating member, 9...Plasma cathode chamber, 10...Through hole, 11...
- Porous electrode, 12... Insulating member, 13...
...Ion generation chamber (made of conductive ceramics), 14...
... Insulating member, 15 ... Bottom plate, 16 ...
... Raw material gas inlet, 17... Slit opening for extracting ions.

Claims (3)

[Claims] (1) In a plasma processing apparatus that electrically turns a predetermined processing gas into plasma and uses this plasma to perform a predetermined processing on an object to be processed, at least a part of the electrode that comes into contact with the processing gas is made of conductive ceramics. A plasma processing apparatus characterized by comprising: (2) An ion source that ionizes a predetermined processing gas introduced into a chamber by irradiating electrons onto the processing gas, wherein the chamber is made of conductive ceramics. (3) An ion source that electrically ionizes a predetermined processing gas introduced into a chamber, characterized in that at least a portion of the electrode that comes into contact with the processing gas is made of conductive ceramics.