JPH07142402A - Method and system for plasma processing - Google Patents

Abstract

PURPOSE:To shorten the time required for plasma processing while increasing the yield of semiconductor devices and simplifying the maintenance/management of the plasma processing system. CONSTITUTION:In the plasma processing method for heat treating a work, before and after machining thereof, by setting the work 1 on a sample stage 3 in a processing chamber 2 fed with gas and supplying high frequency power into the processing chamber 2 to generate plasma for machining the work 1, the work 1 is irradiated with high frequency power on condition that no plasma take place in the processing chamber 2 thus heat treating the work 1. After setting the work 1 on the sample stage 3, the inner wall of the processing chamber 2 is heated with high frequency power. This system shorten the time required for plasma processing thus increasing the yield in the fabrication of semiconductor devices. The plasma processing system is provided with means for controlling the position on the work 1 being irradiated with high frequency power, and means for measuring the temperature distribution of the work 1. This constitution simplify the maintenance and management of the plasma processing system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing method for processing a semiconductor wafer and an apparatus for implementing the same in the manufacture of a semiconductor device, and more particularly to a plasma processing method and an apparatus for implementing the same which require heating of a semiconductor wafer or a processing chamber. It is related to the technology effectively applied to.

[0002]

2. Description of the Related Art A semiconductor device has a manufacturing process
For example, plasma treatment is performed by stacking and patterning wiring layers and insulating layers. The plasma treatment is performed by, for example, a plasma CVD device, a dry etching device, a sputtering device, or the like.

A dry etching apparatus, which is a type of plasma processing apparatus, is provided with a sample table on which a semiconductor wafer is placed in a processing chamber for plasma processing. Further, a gas pipe connecting the cylinder containing the processing gas and the processing chamber, an exhaust pipe for exhausting the gas in the processing chamber, and an exhaust device are provided.

As a means for generating plasma in the processing chamber, a high frequency power application type in which high frequency power is applied to a pair of parallel plate electrodes to generate plasma, or a high frequency generated by a magnetron is guided to the processing chamber by a waveguide. There is a microwave discharge excitation type which guides and generates plasma. The microwave discharge excitation type uses an electromagnetic coil to generate a magnetic field in the processing chamber, causes an electron cyclotron resonance phenomenon, and increases the ionization efficiency of the processing gas.

In the procedure of plasma processing, first, a semiconductor wafer is loaded (loaded) into a processing chamber and set on a sample table.
A material to be etched is deposited on the main surface of the semiconductor wafer, and a mask material such as photoresist is patterned on the material.

Next, the processing chamber is evacuated, a processing gas is introduced into the processing chamber, and a magnetic field is generated in the processing chamber by the electromagnetic coil. The microwave generated by the magnetron is introduced into the processing chamber through the waveguide. Then, plasma is generated in the processing chamber to etch the semiconductor wafer.

After a predetermined etching time has passed,
When the plasma generation by the electromagnetic coil and the magnetron is completed, the process gas introduction valve is closed to stop the process gas introduction.

Next, the semiconductor wafer is unloaded from the processing chamber and the etching process is completed.

Further, in the dry etching apparatus, dust generated from the sample stage or the inner wall of the processing chamber due to the sputtering effect due to the ions, products generated by the etching reaction, etc.
It adheres to the inner wall of the processing chamber and pollutes the processing chamber. If the etching process is continued while the sample chamber is contaminated, the dust will be deposited on the main surface of the semiconductor wafer that is the object to be processed and will serve as a mask. Especially in the case of anisotropic etching,
Since the bottom of the dust is not undercut, it is not etched, and the semiconductor device may be defective. Therefore, in the dry etching apparatus, the heater for heating the processing chamber heats the inner wall of the processing chamber to prevent the adhesion of dust and the like.

[0010]

However, as a result of examining the above-mentioned prior art, the present inventor found the following problems.

In general, the temperature of the sample stage is adjusted so that the wafer is in a temperature condition suitable for etching. However, another heating means must be provided in the vacuum, which causes a problem that the structure of the device becomes complicated.

Further, when heating the processing chamber, if a heater is provided in the processing chamber, the structure of the processing chamber becomes complicated and maintenance of the plasma processing apparatus becomes complicated.

An object of the present invention is to provide a plasma processing method and a plasma processing apparatus which can heat a workpiece or a processing chamber with a simple structure.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0015]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

(1) A workpiece is set on a sample stage in a processing chamber, gas is introduced into the processing chamber, a high frequency wave is introduced into the processing chamber to generate plasma, and the workpiece is processed. It is a plasma processing method which heat-processes the said to-be-processed object before or after a process, Comprising: The said high frequency is irradiated to a to-be-processed object on condition that plasma is not generated in the said process chamber, and the said heat processing is performed.

(2) In the plasma processing method according to (1), the inner wall of the processing chamber is heated by the high frequency.

(3) A processing chamber for processing a workpiece, a sample table on which the workpiece is placed in the processing chamber, a gas introducing means for introducing gas into the processing chamber, and exhaust of gas in the processing chamber. In a plasma processing apparatus having an exhaust unit, a high frequency source for generating a high frequency, and a waveguide for guiding the high frequency to the processing chamber, a unit for varying the irradiation position of the high frequency applied to the workpiece. To provide.

[0019]

According to the above-mentioned means (1), the work is irradiated with the high frequency to heat the work. That is, since the workpiece is directly irradiated with the high frequency and heated, the workpiece can be heated in a short time.

For example, when forming wirings and electrodes on the main surface of a semiconductor wafer, a metal layer such as aluminum laminated on the main surface of the semiconductor wafer is patterned by dry etching. When the semiconductor wafer is irradiated with a high frequency before or after the dry etching treatment, the metal layer absorbs the high frequency, so that only the metal layer can be heat-treated in a short time.

According to the above-mentioned means (2), the inner wall of the processing chamber is heated by the high frequency wave. Since the inner wall of the processing chamber is irradiated with a high frequency to heat it, the heating of the processing chamber can be performed in a short time. As a result, the process completion time of the plasma processing can be shortened.

According to the above-mentioned means (3), the plasma processing apparatus is provided with a means for controlling the irradiation position of the high frequency applied to the workpiece. That is, by changing the high frequency irradiation position suitable for etching the work piece and the high frequency irradiation position suitable for heating the work piece or the processing chamber, heating can be efficiently performed.

Further, the plasma processing apparatus of the present invention can irradiate the workpiece and the processing chamber with high frequency waves to heat them. For this reason, since it is not necessary to provide a heater for heating the processing chamber and a heater for heating the workpiece, the structure of the processing chamber does not become complicated and the maintenance and management of the plasma processing apparatus can be simplified. .

An embodiment of the present invention will be described below with reference to the drawings. In all the drawings for explaining the embodiments, parts having the same function are designated by the same reference numerals, and repeated description thereof will be omitted.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram showing a schematic configuration of a plasma processing apparatus of an embodiment in which the present invention is applied to a dry etching apparatus.

FIG. 2 is a flow chart showing a processing procedure of plasma processing in which the present invention is applied to dry etching processing.

The dry etching apparatus of this embodiment is shown in FIG.
As shown in, a sample table 3 for setting the semiconductor wafer 1 is provided in the processing chamber 2 in which the etching process is performed.

A pipe 4 for introducing an etching gas is connected to the processing chamber 1, and a pipe 7 is connected to the pipe 4 via a valve 5, a mass flow controller 6 and the like. The cylinder 7 is made of chlorine gas (Cl
₂ ), etching gas such as boron trichloride (BCl ₃ ),
Before and after the etching process, nitrogen gas (N ₂ ) or the like to be introduced into the processing chamber 2 is filled.

The processing chamber 2 is evacuated by a vacuum pump 9 connected to the processing chamber 2 through an exhaust port 8. A turbo molecular pump or the like is used as the vacuum pump 9.

A high frequency generator 10 and an electromagnetic coil 11 are provided as means for generating plasma in the processing chamber 2. The high frequency generator 10 is a kind of vacuum tube called a magnetron, and generates a high frequency (2.45 GHz). The high frequency generated by the high frequency generator 10 is applied to the waveguide 1
2 is introduced into the processing chamber 2. Electromagnetic coil 11
Are provided so as to surround the processing chamber 2 and generate a magnetic field in the processing chamber 2.

In the processing chamber 2, an electron cyclotron resonance phenomenon occurs due to the magnetic field generated by the electromagnetic coil 11 and the high frequency generated by the high frequency generator 10 during the etching process, and the ionization efficiency of the etching gas is increased. .

A high frequency power source 13 is provided on the sample table 3 via a capacitor. At the time of etching, the sample stage uses a high frequency power source 13 to generate a high frequency voltage (13.56).
(MHz) is applied, and the sample table 3 has a negative potential due to the self-bias effect, and anisotropic etching is performed.

A waveguide movable member 20 is provided as a means for controlling the irradiation position of the high frequency wave with which the semiconductor wafer 1 is irradiated. The waveguide movable member 20 is composed of a plurality of metal pieces, is supported by the waveguide 12, and is movable by the power of a motor or the like. The waveguide movable member 20 controls the irradiation position by utilizing the characteristic that the traveling direction of the high frequency is bent by the metal.

An infrared temperature detector 21 for detecting infrared rays emitted from the semiconductor wafer 1 on the sample table 3 is provided. The infrared temperature detector 21 sends the temperature distribution of the semiconductor wafer to the control unit 22 as a detection signal. The control unit 22
Based on the detection signal, the waveguide movable member 20 is moved to control the irradiation position of the high frequency irradiated to the semiconductor wafer 1.

Temperature sensors for measuring the temperature of the processing chamber 2 are provided at a plurality of points in the processing chamber. The temperature sensor 23 is
The temperature of the inner wall of the processing chamber 2 is measured, and the measurement signal is sent to the control unit 22.
Send to. The control unit 22 controls the temperature of the processing chamber 2 based on the measurement signal.

Next, the procedure of the dry etching process will be described with reference to the flowchart of FIG.

In this embodiment, the work piece is an aluminum thin film deposited on the main surface of the semiconductor wafer 1, and the plasma treatment is a dry etching treatment for etching the aluminum thin film to form a wiring layer.

Step 201 (semiconductor wafer load):
The semiconductor wafer 1 is loaded (loaded) on the sample table 3 in the processing chamber 2. An aluminum laminated film is formed on the main surface of the semiconductor wafer 1, and photoresist is patterned on the aluminum laminated film using a photoresist as a mask. Then, nitrogen (N ₂ ) is introduced into the processing chamber 2, the vacuum pump 9 is driven, and the inside of the processing chamber 2 is evacuated.

Step 202 (heating of the semiconductor wafer and the processing chamber): With the vacuum pump 9 evacuating the inside of the processing chamber 2, a high frequency is generated by the high frequency generator 10, and the semiconductor wafer 1 and the processing chamber 2 are irradiated with the high frequency. To do. By this irradiation, the semiconductor wafer 1 and the processing chamber 2 are heated, and gas molecules adsorbed on the main surface of the semiconductor wafer 1 and the inner wall of the processing chamber 2 are desorbed.

The temperature distribution of the semiconductor wafer 1 is detected by the infrared temperature detector 21 and sent as a detection signal to the controller 22. Then, the control unit 22 moves the waveguide movable member 20 based on the detection signal, controls the irradiation position of the high frequency, and uniformly heats the semiconductor wafer 1. The heating temperature is, for example, 100 ° C.

Step 203 (etching process): The valve 5 is opened and the etching gas is introduced into the processing chamber 2. The etching gas is chlorine gas (Cl ₂ ), boron trichloride (BCl ₃ ), or the like. The mass flow controller 6 controls the flow rate of the etching gas to a predetermined amount.

After the introduction state of the etching gas is stabilized, the electromagnetic coil 11, the high frequency generator 10 and the high frequency power source 13 are operated to generate plasma in the processing chamber 2. When plasma is generated, the etching gas becomes ions, radicals, etc., and reacts with aluminum to perform etching.

After a predetermined etching time has passed,
Electromagnetic coil 11, high frequency generator 6, and high frequency power supply 13
Then, the generation of plasma is terminated, the valve 5 is closed, and the inflow of etching gas is stopped.

Step 204 (semiconductor wafer and heating of processing chamber): Nitrogen gas (N ₂ ) is flown into the processing chamber 2 through the pipe 4, the vacuum pump 9 evacuates the gas, and the remaining etching gas is exhausted. Then, the high frequency generator 10 is operated to generate a high frequency and irradiate the semiconductor wafer 1.
As a result, the semiconductor wafer 1 is heated, and the etching gas molecules adsorbed on the surface are desorbed.

Step 205 (semiconductor wafer unloading): The semiconductor wafer 1 whose wiring is patterned on the main surface is unloaded from the processing chamber 2 by etching.

As can be seen from the above description, according to the plasma processing apparatus of the present embodiment, the waveguide movable member 20 for controlling the irradiation position of the high frequency wave irradiated to the semiconductor wafer 1 and the processing chamber 2, and the semiconductor wafer. 1, an infrared temperature detector 21 for measuring the temperature distribution, a temperature sensor 23 for measuring the temperature of the processing chamber, an infrared temperature detector 21 and a temperature sensor 23.
The plasma processing apparatus is provided with a control unit 22 that controls the movable waveguide member 20 based on the signal from the. That is,
Since the temperature distribution of the semiconductor wafer 1 can be measured and the high frequency irradiation position can be controlled, the semiconductor wafer 1 can be heated uniformly. As a result, variations in the etching process can be reduced. As a result, the characteristics of the semiconductor device do not vary, and the yield can be improved.

Further, according to the plasma processing apparatus of the present embodiment, the inside of the semiconductor wafer 1 and the processing chamber 2 can be heated by irradiation with high frequency, so that the heater for heating the processing chamber 2 and the semiconductor wafer 1 are heated. It is not necessary to provide a heater to operate. As a result, the structure of the processing chamber 2 does not become complicated, and maintenance of the plasma processing apparatus can be simplified.

Further, according to the plasma processing method of this embodiment, the semiconductor wafer 1 is irradiated with the high frequency wave and the semiconductor wafer 1 is exposed.
Heat treatment. That is, since the semiconductor wafer 1 is irradiated with a high frequency and heated, the semiconductor wafer 1 can be heated in a short time. Further, since the sample table 3 on which the semiconductor wafer 1 is set is not heated, the temperature of the semiconductor wafer 1 is lowered in a short time after the heating process is completed. As a result, the process completion time of plasma processing can be shortened. In particular, when the portion to be subjected to the plasma treatment is an aluminum laminated film (metal) as in the present embodiment, the aluminum laminated film absorbs high frequency, so that the aluminum laminated film can be heat-treated in a short time. Also, the temperature can be lowered in a short time.

After the semiconductor wafer 1 is set on the sample table 3, the inner wall of the processing chamber 2 is heated by the high frequency.
Since the inner wall of the processing chamber 3 is irradiated with the high frequency wave to heat,
The inner wall of the processing chamber 2 can be heated in a short time. As a result, the process completion time of the plasma processing can be shortened.

As described above, the invention made by the present inventor is
Although the present invention has been specifically described based on the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. For example, the plasma processing method and the plasma processing apparatus of the present invention are not limited to the dry etching apparatus, and may be applied to a plasma CVD apparatus, a sputtering apparatus, or the like.

[0051]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

1. The yield of semiconductor devices can be improved.

2. The maintenance and management of the plasma processing equipment can be done easily.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a schematic configuration of a plasma processing apparatus of an embodiment in which the present invention is applied to a dry etching apparatus,

FIG. 2 is a flowchart showing a processing procedure of plasma processing in which the present invention is applied to dry etching processing.

[Explanation of symbols]

1 ... Semiconductor wafer, 2 ... Processing chamber, 3 ... Sample stage, 4 ... Piping, 5 ... Valve, 6 ... Mass flow controller, 7 ... Cylinder, 8 ... Exhaust port, 9 ... Vacuum pump, 10 ... High frequency generator, 11 ... Electromagnetic coil, 12 ... Waveguide, 13 ... High frequency power source, 20 ... Waveguide movable member, 21 ... Infrared temperature detector, 2
2 ... control part, 23 ... temperature sensor.

Claims (3)

[Claims] 1. A workpiece is set on a sample stage in a processing chamber, a gas is introduced into the processing chamber, a high frequency wave is introduced into the processing chamber to generate plasma, and the workpiece is processed.
A plasma processing method for performing heat treatment on the workpiece before or after processing, wherein the high frequency is applied to the workpiece under the condition that plasma is not generated in the processing chamber to perform the heat treatment. And a plasma processing method. 2. The plasma processing method according to claim 1, wherein the high frequency heats the inner wall of the processing chamber. 3. A processing chamber for processing a workpiece, a sample stage on which the workpiece is placed in the processing chamber, a gas introduction unit for introducing gas into the processing chamber, and a gas exhausted from the processing chamber. In a plasma processing apparatus having an exhausting means for generating a high frequency, a high frequency generating source for generating a high frequency, and a waveguide for guiding the high frequency to the processing chamber, the irradiation position of the high frequency applied to the workpiece is variable. A plasma processing apparatus provided with means.