JPH07254500A - Plasma processing device - Google Patents

Abstract

PURPOSE:To restrain collision of a charged particle in plasma with a wall surface, reduce resistance of a plasma generating coil, and simplify a structure in a plasma processing device. CONSTITUTION:A plasma generating coil 24 is arranged in a reaction chamber 10, or a position of the plasma generating coil 24 is made variable, or a surface of the plasma generating coil 24 is covered with an insulating material 25, or the plasma generating coil 24 is formed of a pipe. When high frequency electric power 16 is impressed on the plasma generating coil 24, a generating altenating magnetic field does not penetratingly pass through a reaction chamber wall surface, and collision of a charged particle in plasma 17 with the wall surface can be restrained, and discharge of unnecessary gas from the reaction chamber wall surface can be prevented, and a coil diameter of the plasma generating coil can be reduced, and resistance of the plasma generating coil can be reduced, and the high frequency electric power can be efficiently supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is one of semiconductor manufacturing apparatuses, which uses a plasma to process an object to be processed such as a semiconductor sample.
VD (Chemical Vapor Deposition)
ion) treatment, dry etching, ashing and the like.

[0002]

2. Description of the Related Art A conventional plasma processing apparatus, particularly an etching processing apparatus will be described with reference to FIGS.

A cylinder 2 made of an insulating material such as quartz or ceramics is airtightly connected to the upper part of a vacuum container 1 made of a conductive material and having an airtight structure, and an upper end of the cylinder 2 is airtightly closed by a lid 3 made of a conductive material. A space surrounded by the vacuum container 1, the cylinder 2 and the lid 3 forms a reaction chamber 10.

An exhaust pipe 4 communicates with the lower portion of the vacuum container 1, a vacuum pump 5 is connected to the exhaust pipe 4, and the lid 3
A gas introducing pipe 1 for introducing a reaction gas into the reaction chamber 10
1 is communicated. A flat plate electrode 8 is provided on the inner bottom of the vacuum container 1 via a shield cover 6 and an insulating cover 7.
Is provided. The plate electrode 8 also serves as a mounting table for a substrate 9 to be processed such as a wafer or a glass substrate, and a high frequency power source 13 for electrodes is connected to the plate electrode 8 through a matching unit 12.

A plasma generating coil 14 is provided around the cylinder 2, a coil high frequency power source 16 is connected to one end of the plasma generating coil 14 via a matching unit 15, and the other plasma generating coil 14 is connected. The end is connected to the high frequency power supply 16 for the coil.

In the above conventional plasma processing apparatus, the substrate 9 to be processed is placed on the flat plate electrode 8, the reaction chamber 10 is evacuated by the vacuum pump 5, and the reaction chamber 10 is depressurized. A reactive gas is introduced from the gas introduction pipe 11 into the chamber and the pressure is set by a pressure control device (not shown). When high frequency power output from the coil high frequency power source 16 is applied to the plasma generating coil 14 through the matching unit 15, plasma is generated in the reaction chamber 10 by the action of the alternating electric field and magnetic field generated by the plasma generating coil 14. 17 is generated.

At the same time, the high frequency power output from the electrode high frequency power source 13 is supplied to the flat plate electrode 8 through the matching unit 12 to generate a DC bias voltage between the flat plate electrode 8 and the plasma 17, or Is the plasma 17 itself,
The substrate 9 to be processed on the flat plate electrode 8 is etched by vibrating vertically and utilizing ion energy. The frequency of the electrode high frequency power source 13 is set to an appropriate value according to the type of the substrate 9 to be processed and the target process.

Normally, the frequency of the electrode high frequency power source 13 is selected in the range of 100 kHz to 40 MHz, and the frequency of the coil high frequency power source 16 is selected in the range of 1 MHz to 100 MHz.

[0009]

In the above-described conventional plasma processing apparatus, the plasma generating coil 14 is provided outside the cylinder 2, that is, outside the reaction chamber 10, and high frequency power is supplied to the plasma generating coil 14. The alternating magnetic field generated by the application penetrates the insulating cylinder 2. The charged particles in the plasma 17 are hard to move in the direction of crossing the lines of magnetic force, but can easily move in the direction of the lines of magnetic force, so the charged particles collide with the wall surface of the cylinder 2 (reaction chamber 10). Further, a sheath is generated inside the cylinder near the conductor portion of the plasma generating coil 14, and active species such as ions are accelerated by the sheath voltage to sputter the wall surface of the cylinder 2. Gas is generated from the wall surface of the insulator by the collision of the active species. When the material of the cylinder 2 is quartz, oxygen is released by the collision of the active species, and this oxygen adversely affects the processing such as etching.

When the plasma generating coil 14 is provided outside the cylinder 2, the diameter of the plasma generating coil 14 needs to be at least larger than the outer shape of the cylinder 2. Therefore, the inductance of the plasma generating coil 14 becomes larger than necessary and the resistance increases, and when high frequency power is applied to the plasma generating coil 14, the voltage of the terminal portion of the plasma generating coil 14 rises, which is dangerous. Is. In addition, there is a problem in terms of structure that a shield cover needs to be attached to the outside of the plasma generating coil 14, which makes the structure complicated.

In view of the above situation, the present invention suppresses the collision of charged particles with the wall surface, reduces the resistance of the plasma generating coil, and further simplifies the structure.

[0012]

The present invention relates to a plasma processing apparatus in which a plasma generating coil is provided in a reaction chamber, the position of the plasma generating coil can be changed, or the surface of the plasma generating coil can be changed. The present invention relates to a plasma processing apparatus having a structure in which a coil for plasma generation is covered with an insulating material, or a coil for plasma generation is formed by a pipe, and a heat medium flows through the coil for plasma generation.

[0013]

Since the plasma generating coil is provided in the reaction chamber, the alternating magnetic field generated by applying the high frequency power to the plasma generating coil does not penetrate the reaction chamber wall surface, and the charged particle wall surface Collision can be suppressed, unnecessary gas can be prevented from being discharged from the reaction chamber wall surface, the coil diameter of the plasma generation coil can be reduced, the resistance can be reduced, and high-frequency power can be efficiently supplied, and plasma can be generated when necessary. A cooling medium is circulated in the coil for use to maintain the plasma generating coil at a predetermined temperature.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the same parts as those shown in FIGS. 8 and 9 are designated by the same reference numerals.

An upper end of a vacuum container 20 made of a conductive material and having an airtight structure is hermetically closed by a reaction chamber lid 21 made of a conductive material, and a space surrounded by the vacuum container 20 and the reaction chamber lid 21 is a reaction chamber 1.
Forming 0.

An exhaust pipe 4 is connected to a side surface of the vacuum container 20, an exhaust pipe valve 22, a variable conductance valve 23 and a vacuum pump 5 are connected to the exhaust pipe 4, and the reaction chamber lid 21 is provided with the reaction chamber. A gas introduction pipe 11 for introducing a reaction gas is connected to the chamber 10. A plate electrode 8 is provided on the inner bottom of the vacuum container 20 via a shield cover 6 and an insulating cover 7. The plate electrode 8 also serves as a mounting table for a substrate 9 to be processed such as a wafer or a glass substrate, and the plate electrode 8 is provided with a high frequency power supply 1 for electrodes through a matching unit 12.
3 is connected.

A plasma generating coil 24 facing the plate electrode 8 and parallel to the plate electrode 8 is arranged in the reaction chamber 10. The plasma generating coil 24 is a hollow tube and is made of a material having a low resistance value, but in consideration of contamination of the reaction chamber 10, it is made of a material such as aluminum. The plasma generating coil 24 has one or more turns and an arbitrary number of turns, and the surface thereof is covered with an insulating tube 25. Examples of the material of the insulating tube 25 include fluororesin, ceramics, quartz and the like. Since the plasma generation coil 24 is in the reaction chamber 10, a self-bias voltage is generated in the plasma generation coil itself. Therefore, the surface of the plasma generating coil 24 is sputtered with ions. The insulating tube 25 prevents the metal surface from being directly exposed to the reaction chamber 10, prevents metal atoms from being released into plasma by ion sputtering, and prevents the substrate 9 to be processed from being contaminated. To do.

The terminals of the plasma generating coil 24 are hermetically penetrated through the reaction chamber lid 21 via a vacuum seal block 26. The vacuum seal block 26 is provided with a sealing member such as an O-ring to hermetically seal the penetrating portion of the plasma generating coil 24 and to form the plasma generating coil 2
4 is held so as to be movable in the vertical direction, and the position of the plasma generating coil 24 in the height direction can be easily changed.

A high frequency power supply 16 for coils is connected to one end of the coil 24 for plasma generation through a matching unit 15, and the other end of the coil 24 for plasma generation is connected to the high frequency power supply 16 for coils. A cooling pipe 27 connected to a cooling source (not shown) communicates with both ends of the plasma generating coil 24.

A semiconductor sample is provided on the side wall of the vacuum container 20,
For example, a horizontally flat transfer port 28 for loading and unloading a substrate 9 to be processed such as a wafer is provided, a gate valve 29 is provided at the transfer port 28, and a transfer chamber 30 is continuously provided via the gate valve 29. A transfer unit (not shown) is provided in the transfer chamber 30.

The operation will be described below.

The substrate 9 to be processed is placed on the plate electrode 8, the reaction chamber 10 is evacuated by the vacuum pump 5, and the reaction gas is introduced from the gas introduction pipe 11 into the reaction chamber 10 in a depressurized state. It is introduced and the pressure is set by a pressure control device (not shown). The matching device 1 applies high frequency power output from the coil high frequency power supply 16 to the plasma generating coil 24.
5, the plasma generating coil 24
Plasma 17 is generated in the reaction chamber 10 by the electric field and magnetic field of the alternating current generated by.

A cooling medium, such as water, is circulated from the cooling pipe 27 into the plasma generating coil 24 to cool the plasma generating coil 24 so that the temperature does not exceed a required temperature. If the temperature rise of the plasma generating coil 24 does not pose a problem, it is not necessary to flow the cooling medium, and in this case, the plasma generating coil 24 may be a solid material instead of the pipe material.

At the same time, high-frequency power output from the electrode high-frequency power source 13 is supplied to the flat plate electrode 8 via the matching unit 12 to generate a DC bias voltage between the flat plate electrode 8 and the plasma 17, or Is the plasma 17 itself,
The substrate 9 to be processed on the flat plate electrode 8 is etched by vibrating vertically and utilizing ion energy.

As described above, the plasma generating coil 2
Since the position of 4 in the height direction can be changed, the position of the plasma generating coil 24 can be adjusted to change the plasma generation state.

The frequency of the electrode high frequency power source 13 is set to an appropriate value according to the type of the substrate 9 to be processed and the process to be processed. Usually, the frequency of the electrode high frequency power source 13 is 100 kHz to 40 MHz, and the frequency of the coil high frequency power source 16 is 1 MHz to 100 MHz.
Select in the range of z.

As described above, the plasma generating coil 24 is provided in the reaction chamber 10. In the above embodiment, the plasma generating coil 24 was supported by the terminals of the plasma generating coil 24. However, when the plasma generating coil 24 cannot be fixed by the terminals, as shown in FIG. It is fixed to the reaction chamber lid 21 via the fixed legs 31.
Further, the fixing position is not limited to the reaction chamber lid 21, but may be fixed to the side wall of the vacuum container 20 or the bottom surface as shown in FIGS. Also, these mounting positions may be combined. Furthermore,
The position of the plasma generating coil 24 may be changed by changing the mounting position of the coil fixing foot 31.

Further, the position of penetrating the terminal of the plasma generating coil 24 to the outside is not limited to the reaction chamber lid 21, but may be the side wall or the bottom of the vacuum container 20.

Further, depending on the process conditions, the insulating tube 25 on the surface of the plasma generating coil 24 can be omitted, and the shape of the plasma generating coil 24 is a quadrangle as shown in FIGS. 6 and 7. It may be a coil or a circular coil.

[0031]

As described above, according to the present invention, since the plasma generating coil is provided in the reaction chamber, the alternating magnetic field generated by applying the plasma generating coil to the reaction chamber penetrates the wall surface of the reaction chamber. Since there is no need to release unnecessary gas from the wall of the reaction chamber, there is no need to provide a cylinder of insulating material, and the shield case for the plasma generation coil is not required, which simplifies the structure and further generates plasma. The coil diameter of the working coil can be reduced, the resistance can be reduced, and high-frequency power can be efficiently supplied.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a partially broken perspective view showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a method of supporting a coil.

FIG. 4 is a cross-sectional view showing a method of supporting a coil.

FIG. 5 is a cross-sectional view showing a method of supporting a coil.

FIG. 6 is an outline view showing the shape of a plasma generating coil.

FIG. 7 is an external view showing the shape of a plasma generating coil.

FIG. 8 is a cross-sectional view showing a structure of a conventional example.

FIG. 9 is a perspective view showing a conventional example.

[Explanation of symbols]

 8 Flat Plate Electrode 9 Processed Substrate 11 Gas Introducing Tube 12 Matching Machine 16 High Frequency Power Supply for Coil 21 Reaction Chamber Lid 24 Plasma Generating Coil 25 Insulating Tube 27 Cooling Tube

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H01L 21/31 H01L 21/31 C

Claims (7)

[Claims] 1. A plasma processing apparatus, wherein a plasma generating coil is provided in a reaction chamber. 2. The plasma processing apparatus according to claim 1, wherein the position of the plasma generating coil can be changed. 3. The plasma processing apparatus according to claim 1, wherein the surface of the plasma generating coil is covered with an insulating material. 4. The plasma processing apparatus according to claim 1, wherein the plasma generating coil is formed of a pipe, and a heat medium is circulated through the plasma generating coil. 5. The plasma processing apparatus according to claim 1, wherein the fixed portion of the plasma generating coil is a ceiling portion of the vacuum container. 6. The plasma processing apparatus according to claim 1, wherein the fixing portion of the plasma generating coil is a side wall portion of the vacuum container. 7. The plasma processing apparatus according to claim 1, wherein the fixed portion of the plasma generating coil is the bottom portion of the vacuum container.