JP2003249488A - Plasma processing system and method for fabricating semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing system and a method for fabricating a semiconductor device in which cleaning can be carried out neither too much nor too less. <P>SOLUTION: The plasma processing system 100 comprises a processing chamber 10, means 20 and 22 for measuring the degree of contamination on the inner wall of the processing chamber 10, means for cleaning the processing chamber 10, means for determining cleaning conditions based on the degree of contamination, and means 40 for setting the cleaning conditions in the cleaning means. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a semiconductor device manufacturing method.

[0002]

BACKGROUND ART When a wafer is plasma-processed in a processing chamber of a plasma processing apparatus, a reaction product (polymer) is generated and the reaction product adheres to an inner wall of the processing chamber. Specifically, in the case of plasma etching, the reaction product of the material to be etched and the etching gas adheres to the inner wall of the processing chamber. In the case of the plasma film forming process, a deposition material which is a reaction product of gases adheres to the inner wall of the processing chamber.

Therefore, after the wafer is plasma-processed, the processing chamber is generally cleaned.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma processing apparatus and a method for manufacturing a semiconductor device, which can perform cleaning without excess or deficiency.

Another object of the present invention is to provide a plasma processing apparatus and a semiconductor device manufacturing method which can determine an appropriate cleaning time.

[0006]

[Means for Solving the Problems] 1. Plasma processing apparatus 1.1 First plasma processing apparatus A first plasma processing apparatus of the present invention is a plasma processing apparatus including a processing chamber, and a measuring unit for measuring a degree of contamination of an inner wall of the processing chamber, A cleaning unit for cleaning the processing chamber and a unit for determining a cleaning condition based on the degree of contamination and setting the cleaning condition in the cleaning unit are included.

According to the present invention, the cleaning condition is determined based on the measured degree of contamination. For this reason,
It is possible to achieve proper cleaning. Moreover, since the degree of contamination after each cleaning step can be made constant, the processing characteristics during plasma processing can be stabilized.

1.2 Second Plasma Processing Apparatus A second plasma processing apparatus of the present invention is a plasma processing apparatus including a processing chamber, wherein the measuring means measures the degree of contamination of the inner wall of the processing chamber, and It includes a cleaning unit for cleaning the processing chamber, and a unit for determining a cleaning time based on the degree of contamination and controlling the start of the cleaning unit.

According to the present invention, since the cleaning time is determined based on the degree of contamination, it is possible to prevent the cleaning process from being performed excessively and improve the throughput. Further, it is possible to prevent the plasma processing step from being performed after the degree of contamination reaches the range to be cleaned. Therefore, the yield can be improved.

The first and second plasma processing apparatuses of the present invention can take the following modes.

In the measuring means, the processing chamber has a light-transmitting inner wall in part or in whole, and the emission intensity of plasma is measured through the light-transmitting inner wall before cleaning the processing chamber. Based on the detection means for detecting and the emission intensity,
A calculation means for calculating the degree of dirt can be included.

There is a correlation between the intensity of light that has passed through the light-transmitting inner wall and the degree of contamination, as will be described later. Therefore, the measuring means as described above can reliably measure the degree of contamination.

The detection means can detect the emission intensity of plasma during plasma processing of the wafer. This makes it possible to omit the step of separately emitting plasma to measure the degree of contamination, and improve the throughput.

The plasma processing apparatus is a plasma etching processing apparatus, and includes determination means for determining the end point based on the emission intensity of plasma during plasma processing, and the determination means detects for detecting the emission intensity of plasma. The detecting means of the determining means may also serve as the detecting means of the measuring means.

2. 2. Method of Manufacturing Semiconductor Device 2.1 Method of Manufacturing First Semiconductor Device A method of manufacturing a first semiconductor device of the present invention is a method of manufacturing a semiconductor device using a plasma processing apparatus including a processing chamber. A step of detecting the degree of contamination of the inner wall of the chamber; a step of determining etching conditions for cleaning the processing chamber based on the degree of contamination;
The method includes the step of cleaning the processing chamber based on the etching conditions.

According to the present invention, the cleaning condition is determined based on the measured degree of contamination. For this reason,
It is possible to achieve proper cleaning. Moreover, since the degree of contamination after each cleaning step can be made constant, the processing characteristics during plasma processing can be stabilized.

2.2 Second Method for Manufacturing Semiconductor Device A second method for manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device using a plasma processing apparatus including a processing chamber, wherein The method includes the steps of detecting the degree of dirt on the inner wall, and determining the cleaning time of the processing chamber based on the degree of dirt.

According to the present invention, since the cleaning timing is determined based on the degree of contamination, it is possible to prevent the cleaning process from being carried out excessively and to improve the throughput. Further, it is possible to prevent the plasma processing step from being performed even after the degree of contamination reaches the range to be cleaned. For this reason,
The yield can be improved.

The method of manufacturing a semiconductor device according to the present invention is
The method is not limited to the method for manufacturing a semiconductor integrated circuit, and transistors or wirings are formed on a substrate, including, for example, a method for manufacturing a liquid crystal display.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings.

1. Plasma Processing Apparatus FIG. 1 is a diagram schematically showing a plasma processing apparatus according to the embodiment.

The plasma processing apparatus 100 includes a processing chamber 10 for performing plasma processing. And the plasma processing apparatus 1
00 further includes a photodetector 20 for detecting the emission intensity of plasma, a contamination degree deriving means 22, a cleaning condition determining means 30, and a cleaning control means 40.

The means for generating plasma may be parallel plate type plasma generating means, as shown in FIG. For example, by applying a high frequency to the electrode 14 and grounding the processing chamber 10 to discharge the plasma, plasma can be generated. The plasma generating means is not particularly limited as long as it can generate plasma, and may be a microwave type plasma generating means. Further, as shown in FIG. 1, an electromagnetic coil 50 may be provided on the side of the processing chamber to provide a mechanism for generating a magnetic field.

A viewing window 12 is provided in the processing chamber 10. Then, between the viewing window 12 and the photodetector 20,
An optical fiber 60 is provided.

The photodetector 20, the contamination degree deriving means 22,
The cleaning condition determining means 30 and the cleaning control means 40 will be specifically described in the section "How to use" described later.

2. First Semiconductor Device Manufacturing Method 2.1 Process A first semiconductor device manufacturing method will be described with reference to FIGS. 2 and 3.

First, as shown in FIG. 2, a wafer is placed on the electrode 14.

Next, the wafer 70 in the processing chamber 10 is subjected to plasma processing (eg, etching processing, film forming processing, ashing processing). Specifically, a reaction gas is introduced and high-frequency power is applied to the electrode 14 to generate plasma, and the wafer is plasma-processed. At this time, the light generated in the plasma is introduced into the optical fiber 60 through the viewing window of the processing chamber 10,
Photodetector (photoelectric device such as Photomaru) 20
To detect.

After the plasma processing is completed, as shown in FIG. 3, the cleaning means is controlled by the cleaning control means 40 in which the cleaning conditions are set, and the processing chamber 10 is cleaned. This cleaning means
A plasma generation means for plasma treatment can be applied.
As the cleaning control means 40, for example, control means such as gas flow rate, pressure, RF power, temperature can be applied. A cleaning means may be separately provided.
Cleaning may be done in one step, or
You may perform in multiple steps.

2.2 Method of Determining Cleaning Condition The cleaning condition can be determined as follows. As described above, during the plasma processing on the wafer 70, the light generated in the plasma is detected by the photodetector 20 through the viewing window 12. The intensity of the emitted light is converted into a current or a voltage and output to a dirt degree deriving means (for example, a microcomputer) 22. The stain degree deriving means 22 calculates and derives the stain degree. Specifically, as will be described later, there is a correlation between the intensity of light that has passed through the viewing window 12 and the amount of reaction products attached to the inner wall of the processing chamber 10 (hereinafter referred to as “dirt level”). That is, the smaller the intensity of the light passing through the viewing window 12, the greater the degree of contamination of the inner wall of the processing chamber 10. Therefore, the degree of contamination of the inner wall of the processing chamber 10 can be derived based on the intensity of light that has passed through the viewing window 12. The information on the degree of dirt is output to the cleaning condition determining means 30.
Then, the cleaning condition determining means 30 determines the cleaning condition based on the information on the degree of contamination. Examples of the cleaning condition include cleaning time, cleaning gas flow rate, processing pressure, and power (for example, RF power).

The higher the cleaning gas flow rate, the greater the cleaning strength. Further, in the case of cleaning by a chemical method, the density of gas is increased by increasing the processing pressure, and the cleaning strength can be increased. In case of cleaning by physical method,
The cleaning strength can be increased by increasing the power (for example, RF power) or decreasing the pressure.

2.3 Correlation between Luminous Intensity and Contamination Degree There is a correlation between the amount of the reaction product adhered to the inner wall of the processing chamber 10 (degree of contamination) and the luminescence intensity of light passing through the inner wall of the processing chamber. Explain the reason.

When the amount of the reaction product adhered to the inner wall of the processing chamber 10 is large, the corresponding amount of plasma light is absorbed by the reaction product 80 near the inner wall of the processing chamber 10 as shown in FIG. To do. For this reason, if the amount of the reaction product attached to the inner wall of the processing chamber 10 is large, the photodetector 2 is correspondingly increased in amount.
The intensity of the light detected by 0 becomes weak. As a result, the emission intensity of the light passing through the inner wall of the processing chamber 10 and the processing chamber 10
Has a correlation with the amount of reaction products attached to the inner wall of the.

2.4 Functions and Effects The functions and effects of this semiconductor device manufacturing method will be described below.

(1) Since the cleaning conditions are determined based on the degree of contamination, cleaning can be performed according to the degree of contamination (amount of reaction product), so that cleaning that is just enough can be realized. That is, since it is possible to avoid unnecessary cleaning, it is possible to shorten the cleaning time. In addition, since insufficient cleaning can be prevented, the frequency of cleaning by opening the processing chamber to the atmosphere can be reduced.

(2) By controlling the cleaning conditions, the amount of reaction products (degree of contamination) after each cleaning step can be made constant. As a result, the following operational effects are exhibited. The plasma processing characteristics are affected by the amount of reaction products attached to the inner wall of the processing chamber 10. Therefore, processing characteristics (etching characteristics, film formation characteristics)
Can be stabilized.

It is also conceivable to completely remove all the reaction products attached to the inner wall of the processing chamber. However, if all the reaction products are removed, the plasma processing characteristics of the wafer may be adversely affected. That is, in order to improve the plasma processing characteristics, it is necessary that some reaction products adhere to the inner wall of the processing chamber 10. It is considered that this is because the reaction product also contributes to the plasma processing.

(3) For example, the plasma etching apparatus has the following effects. By determining the cleaning conditions so that the amount of the reaction product becomes constant, the amount of the reaction product during each plasma etching process can be made constant. Therefore, the profile of the peak value of the light measured for determining the end point can be made constant between the plasma etching processes. Therefore, the end point detection can be stabilized.

2.5 Comparative Example In some cases, cleaning may be performed with fixed cleaning conditions. In this case, there are the following problems.

(1) When cleaning is performed under the condition of uniformly fixing, the cleaning may be excessively performed. For this reason, the cleaning time becomes longer by the amount of extra cleaning. On the other hand, in some cases, the cleaning may be insufficient. In that case, after the cleaning, the reaction product attached to the inner wall of the processing chamber remains excessively. Therefore, the processing chamber is opened to the atmosphere for cleaning. There is a need.

(2) If cleaning is performed with fixed cleaning conditions, the degree of contamination of the inner wall of the processing chamber will differ after cleaning. Further, the characteristics of plasma processing are affected by the degree of contamination of the processing chamber. Therefore, as the number of processed wafers increases, the plasma processing characteristics change, and the plasma processing characteristics between wafers vary.

(3) If cleaning is performed with fixed cleaning conditions, the degree of contamination of the processing chamber will differ for each plasma etching process. Even in the same plasma etching process, if the degree of contamination of the processing chamber is different, as shown in FIG. 5, between the plasma etching processes (a) to (c), the intensity of light used for the end point determination is The peak value profile will be different.
That is, the intensity of the detected light decreases as the plasma etching process is performed in a state where the degree of contamination is high (the process (c) has the lowest emission intensity). Therefore, it is difficult to determine the end point during the plasma etching process.

2.6 Modification In the above-described embodiment, the degree of contamination is measured during the etching process on the wafer 70. However, the present invention is not limited to this, and the degree of contamination may be measured after etching the wafer 70.

3. Method of Manufacturing Second Semiconductor Device Hereinafter, a method of manufacturing the second semiconductor device will be described.
This method is an example in which cleaning is performed after performing a plasma treatment process on a wafer a plurality of times.

For each processing step for the wafer, the degree of contamination is measured by the same method as the method for manufacturing the first semiconductor device. Then, depending on the degree of the stain, whether or not to clean is determined, and the cleaning time is determined.

By determining the cleaning timing in this way, the following operational effects are exhibited.

As shown in FIG. 6, as the number of plasma treatments on the wafer increases, the degree of contamination increases. Conventionally, cleaning was performed after performing the plasma treatment process SC a predetermined number of times. However, the number of times S
When C is fixed, when the treatment step (e) in which stains are unlikely to occur is performed a plurality of times, cleaning is performed even if the degree of stains does not reach the range to be cleaned at the number of treatments SC. Become. For this reason, excessive cleaning is performed and throughput is deteriorated. On the contrary, when the processing step (f) in which the stain is likely to occur is performed a plurality of times, the cleaning is not performed even if the stain degree has already reached the range to be cleaned before the number of processing times SC.

However, when the degree of contamination is measured and the cleaning time is determined based on the degree of contamination as in the present embodiment, it is possible to prevent an excessive cleaning step and improve throughput. You can Further, it is possible to prevent the plasma processing step from being performed even after the degree of contamination reaches the range to be cleaned. Therefore, the yield can be improved.

4. Modification (1) When the plasma processing apparatus 100 is a plasma etching processing apparatus, the photodetector 20 can also serve as a photodetector used for determining the end point of etching.

(2) With respect to the detected light, only light having a predetermined wavelength may be taken out by the optical filter, and the taken-out light may be detected by the photodetector 20.

(3) When the plasma processing apparatus 100 is a plasma film forming apparatus, the plasma generating means for plasma film forming can also be used as the cleaning means. At this time, the gas introduced at the time of cleaning needs to be a gas having a property of etching the reaction product.

(4) When the processing chamber 10 itself is made of a light-transmitting material (eg, quartz), the viewing window 12 is unnecessary.

The present invention is not limited to the above-mentioned embodiments, but various modifications can be made within the scope of the gist of the present invention.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a plasma processing apparatus according to an embodiment.

FIG. 2 is a diagram showing a plasma processing process for a wafer.

FIG. 3 is a diagram showing a cleaning process.

FIG. 4 is a diagram schematically showing dirt in the processing chamber.

FIG. 5 is a diagram for explaining a function and effect.

FIG. 6 is a diagram for explaining a function and effect.

[Explanation of symbols]

10 processing room 12 Peep window 14 electrodes 20 photo detector 30 Cleaning condition determining means 40 Cleaning control means 50 electromagnetic coil 60 optical fiber 70 wafers 100 plasma processing equipment

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G075 AA24 AA30 AA57 AA61 AA65                       BB10 BC04 BC06 CA47 DA02                       EB01 FC04                 4K030 DA06 JA00 JA13 KA39 LA15                 5F004 AA15 BD01 BD04 CA08 CB02                       CB09

Claims (7)

[Claims] 1. A plasma processing apparatus including a processing chamber, comprising: a measuring unit for measuring a degree of contamination on an inner wall of the processing chamber; a cleaning unit for cleaning the processing chamber; and a cleaning condition based on the degree of contamination. Decide,
And a means for setting the cleaning condition to the cleaning means. 2. A plasma processing apparatus including a processing chamber, comprising: a measuring unit for measuring a degree of contamination of an inner wall of the processing chamber; a cleaning unit for cleaning the processing chamber; and a cleaning time based on the degree of contamination. Decide,
A plasma processing apparatus comprising: means for controlling the start of the cleaning means. 3. The measuring means according to claim 1, wherein the processing chamber has a partially or entirely light-transmissive inner wall, and the light-transmissive inner wall is provided before cleaning of the processing chamber. A plasma processing apparatus comprising: a detection unit configured to detect the emission intensity of plasma through the calculation unit; and a calculation unit configured to calculate the contamination degree based on the emission intensity. 4. The plasma processing apparatus according to claim 3, wherein the detection means detects the emission intensity of plasma during plasma processing of the wafer. 5. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma etching processing apparatus, and includes a determination unit that determines an end point based on the emission intensity of plasma during plasma processing. The determination unit includes a detection unit that detects the emission intensity of plasma, and the detection unit of the determination unit also serves as the detection unit of the measurement unit. 6. A method of manufacturing a semiconductor device using a plasma processing apparatus including a processing chamber, comprising: detecting a degree of contamination of an inner wall of the processing chamber; A method of manufacturing a semiconductor device, comprising: a step of determining etching conditions for cleaning; and a step of cleaning the processing chamber based on the etching conditions. 7. A method of manufacturing a semiconductor device using a plasma processing apparatus including a processing chamber, comprising: detecting a degree of contamination of an inner wall of the processing chamber; and cleaning the processing chamber based on the degree of contamination. A method of manufacturing a semiconductor device, including the step of determining a time.