JP2001284322A - Plasma process apparatus, method for controlling the same and method for determining defective product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma process device and a defective product determing method, which can detect defective products. SOLUTION: A plasma process device performing a processing using plasma is provided with a measuring means 1 and an evaluation means 2. The measuring means 1 disperses light from plasma and measures (S2) the first light emission intensity of light in a first wavelength region. The evaluation means 2 calculates (S3) an evaluation value, using the measured value of first light emission intensity measured by the measuring means 1. A reference value, using first light emission intensity when the processing normally is preformed, is compared with the evaluation value. Thus, whether a defect occurs has occurred in the object under the processing is judged, (S4).

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, a method for controlling the plasma processing apparatus, and a method for determining a defective product. More specifically, the present invention relates to a plasma processing apparatus using data obtained by spectrally separating light from plasma,
The present invention relates to a method for controlling a plasma processing apparatus and a method for determining a defective product.

[0002]

2. Description of the Related Art Conventionally, in the manufacturing process of a semiconductor device such as a liquid crystal display device, various manufacturing processes such as a sputtering device, a CVD device, a dry etching device, a wet etching device, a photolithography device, a cleaning device, a baking device, and a doping device are performed. The device is being used. Among such manufacturing apparatuses, for example, a CVD apparatus and a dry etching apparatus are plasma processing apparatuses that perform processes such as film formation or etching using plasma.
As a control method for controlling the film forming processing in such a CVD apparatus or the etching processing in a dry etching apparatus, a control method based on time, a control method based on a change in pressure in a reaction chamber, and a change with time of the emission spectrum intensity of an etching gas are described. Various methods are used, such as the control method used.

[0003]

In a CVD apparatus, it is necessary to terminate a film forming process when a required film is formed to a predetermined film thickness. Used the film formation processing time. In other words, utilizing the fact that there is a correlation between the processing time and the film thickness of the film to be formed, the processing time required to form a film having the required film thickness is set in advance, and this setting is performed. The control is performed such that the film forming process is terminated when the processing time has elapsed. In the control (time control) for setting such a processing time, a change in process conditions such as a state of plasma during a film forming process is not reflected in the control. In some cases, it varied. For this reason, it has been difficult to control the thickness of the formed film with high accuracy.

[0004] In the film forming process using such a CVD apparatus, the quality of a film formed varies due to a change in process conditions and the like, and as a result, the manufactured semiconductor device may be defective. The occurrence of such defective products has been found in an inspection process performed after a manufacturing process such as a film forming process. However, if the occurrence of such a defective product can be detected during the film forming process, it is possible to quickly take measures such as adjusting the process conditions. As a result, the manufacturing efficiency of the semiconductor device can be improved.

Further, in a dry etching apparatus, a control method utilizing the emission spectrum intensity of light from an etching gas in a reaction chamber to detect an end point of an etching process is disclosed in, for example, JP-A-11-214360. I have. In JP-A-11-214360, light from an etching gas is separated at a specific wavelength using a dichroic mirror, and the separated light is received by first and second light receiving elements, and the first and second light receptions are performed. The end point of the etching process is detected using data such as the output ratio of the element. However, when the end point of the etching process is detected using only two data from the first and second light receiving elements as described above, it is necessary to detect the end point of the etching process with high accuracy due to the influence of data variation and the like. Is considered difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a plasma processing apparatus capable of controlling a film forming process with high accuracy and a control method thereof. To provide.

Another object of the present invention is to provide a plasma processing apparatus and a defective product judging method capable of detecting occurrence of a defective product.

Another object of the present invention is to provide a plasma processing apparatus capable of detecting an end point of an etching process with high accuracy and a control method thereof.

[0009]

A plasma processing apparatus according to one aspect of the present invention is a plasma processing apparatus for performing a process using plasma, and includes a measuring unit and an evaluating unit. The measuring means disperses the light from the plasma and measures the first emission intensity of the light in the first wavelength region.
The evaluation means calculates an evaluation value using the first emission intensity measurement value measured by the measurement means, and a reference value and an evaluation value using the first emission intensity when the processing is performed normally. Then, it is determined whether or not a failure has occurred in the processing target being processed.

Here, when the processing situation in the processing using plasma (plasma process) changes, the spectrum of light from the plasma used in the processing changes. This is due to the fact that each substance emits light of a specific wavelength in the plasma, so that the processing status changes and the amount of the substance involved in the processing in the plasma changes.
For this reason, the spectrum of light from the plasma differs between when the plasma process is performed normally and when a defect occurs in the processing target due to an abnormal reaction. As a result, the light from the plasma is separated and the first light in the first wavelength region including the specific wavelength of the substance involved in the plasma process is emitted.
Is measured, and the evaluation value is calculated as described above,
By comparing with a reference value, the occurrence of a defect can be quickly detected during the plasma process.

In the plasma processing apparatus according to the first aspect, the measuring means has means for measuring a second emission intensity of light in a second wavelength region that is a wavelength region different from the first wavelength region. Is preferred. In the evaluation means, it is preferable to calculate, as an evaluation value, the ratio of the second measured light emission intensity measured by the measuring means to the first measured light emission intensity, and to calculate the ratio when the processing is performed normally. It is preferable that the ratio between the measured value of the light emission intensity and the first measured value of the light emission intensity is used as the reference value.

In a reaction in a plasma process (for example, a film formation reaction), when a normal reaction is occurring, the abundance ratio of substances involved in the reaction in the plasma shows a substantially constant predetermined value. When the absolute value of the emission intensity measurement value fluctuates due to a change in conditions such as a film formation rate while a normal reaction is occurring, the change in the abundance ratio is relatively larger than the change in the absolute value. Less. For this reason, if the ratio of the second emission intensity measurement value to the first emission intensity measurement value is used as the evaluation value, it is possible to suppress a decrease in the accuracy of defective product determination due to a change in the absolute value of the emission intensity measurement value. Therefore, occurrence of defective products can be detected with higher accuracy.

[0013] In the plasma processing apparatus according to the first aspect, the measuring means includes a first wavelength region, and
It is preferable to have means for measuring the broad-band emission intensity for light in a wide-band wavelength range wider than the above-mentioned wavelength range. The evaluation means calculates, as another evaluation value, a ratio of the first emission intensity measurement value to the wide emission intensity measurement value measured by the measurement means, and calculates the ratio of the wide emission intensity measurement value when the processing is performed normally. Using the ratio of the first emission intensity measurement value as another reference value, processing is performed using another result of comparing the other evaluation value with another reference value and a result of comparing the evaluation value with the reference value. It is preferable to determine whether a defect has occurred in the target.

In this case, the measured value of the broad-band emission intensity corresponds to the abundance of a plurality of types of substances in the plasma corresponding to the measured wide-band wavelength region. If the width of the wide wavelength region is set so as to cover the wavelength of light from the substance involved in the plasma process, the above other evaluation values are calculated based on the total amount of the substance corresponding to the first wavelength region in the plasma. The abundance ratio to the substance is approximately indicated. When an abnormal reaction occurs, it is considered that the abundance ratio of such a specific substance to all the substances also fluctuates. Therefore, the use of the above other evaluation values makes it possible to detect the occurrence of a defect with higher accuracy.

In the plasma processing apparatus according to the first aspect, the measuring means includes the first wavelength region, and
It is preferable to have means for measuring the broad-band emission intensity for light in a wide-band wavelength region wider than the above-mentioned wavelength region. In the evaluation means, it is preferable to calculate, as an evaluation value, a ratio of the first emission intensity measurement value to the wide-area emission intensity measurement value measured by the measurement means.

In this case, as described above, if the width of this wide wavelength region is set so as to cover the wavelength of light from a substance involved in the plasma process, the other evaluation values will be in the first wavelength region. The abundance ratio of the corresponding substance to all the substances in the plasma will be approximately indicated. Therefore, it is possible to reliably detect a defect that occurs under a process condition in which the abundance ratio of the specific substance to all the substances fluctuates.

A plasma processing apparatus according to another aspect of the present invention is a plasma processing apparatus for performing a film forming process using plasma, and includes a measuring unit and an evaluating unit. The measuring means disperses the light from the plasma and measures the first emission intensity of the light in the first wavelength region. The evaluation means calculates an evaluation value using a time integration value of the first emission intensity measurement value measured by the measurement means, and when the film thickness of the film formed by the film forming process reaches a predetermined thickness. By comparing the reference value using the time integration value of the first emission intensity measurement value with the evaluation value, it is determined whether or not the film thickness of the film formed in the film formation processing has reached a predetermined thickness. .

Here, there is a correlation between the film forming speed and the concentration of the substance in the plasma involved in the film forming reaction. Since there is a correlation between the concentration of the substance in the plasma involved in the film formation reaction and the light emission intensity in the wavelength region including the wavelength corresponding to the substance, the film formation rate and the light emission intensity are correlated. There is. For this reason, there is a certain proportional relationship between the film thickness of the film formed by the film forming process and the time integration value of the emission intensity measurement value. Therefore, if the reference value is determined in advance by determining this proportional relationship by an experiment or the like, it can be easily determined whether or not the thickness of the film formed as described above has reached a predetermined thickness. If the plasma processing apparatus is controlled so as to end the film forming process when it is detected that the formed film has a predetermined thickness, the film having the predetermined thickness can be reliably formed. .

[0019] In the plasma processing apparatus according to the above another aspect, the measuring means has means for measuring a second emission intensity of light in a second wavelength region that is a wavelength region different from the first wavelength region. Is preferred. In the evaluation means, it is preferable that the evaluation value is calculated using the time integration value of the second emission intensity measurement value measured by the measurement means and the time integration value of the first emission intensity measurement value.

In this case, when there are a plurality of substances involved in the film forming process, the first and second emission intensities are measured in the wavelength region including the wavelength corresponding to each of the substances as described above. If the evaluation value is calculated using the measured values of the above, it can be determined with higher accuracy whether or not the film thickness of the formed film has reached a predetermined film thickness. In addition, as an evaluation value,
For example, data obtained by adding the time integration value of the second emission intensity measurement value and the time integration value of the first emission intensity measurement value can be used.

In the plasma processing apparatus according to another aspect, the measuring means includes a first wavelength region, and
May be provided for measuring a wide-band emission intensity of light in a wide-band wavelength region wider than the above-mentioned wavelength region. The evaluation means may calculate the evaluation value by using the time integrated value of the wide-area light emission intensity measured by the measurement means and the time integrated value of the first light emission intensity measured value.

In this case, the measured value of the broad-band emission intensity reflects the concentrations of a plurality of substances involved in the film forming process. For this reason,
As in the case of the first emission intensity measurement value, it is considered that there is a certain proportional relationship between the film thickness of the film formed by the film forming process and the time integration value of the wide area emission intensity measurement value. As a result, the evaluation value is calculated using both the time integration value of the wide-range emission intensity measurement value and the time integration value of the first emission intensity measurement value, so that the control of the film thickness can be performed with higher accuracy. It is possible to do.

A plasma processing apparatus according to another aspect of the present invention is a plasma processing apparatus for performing an etching process using plasma, and includes a measuring unit, a calculating unit, and a detecting unit. The measuring means disperses the light from the plasma and measures the first to third emission intensities of the light in the first to third wavelength ranges, respectively. The calculating means uses the first to third emission intensity measured values measured by the measuring means,
The ratio between the first emission intensity measurement value and the second emission intensity measurement value is calculated as a first evaluation value, and the ratio between the first emission intensity measurement value and the third emission intensity measurement value is calculated as a second evaluation value. Is calculated as the evaluation value of The detecting means sets the ratio of the first measured emission intensity and the second measured emission intensity when the etching process is completed to a first reference value, and sets the first emission intensity measurement when the etching process is completed. The ratio between the measured value and the third measured emission intensity is defined as a second reference value, and the first and second evaluation values are compared with the first and second reference values, respectively. Detect the end.

Here, in the etching process, when a layer made of a specific material to be etched is etched, the abundance ratio of the substance contained in the plasma as a result of the etching process is substantially constant. Becomes
When the etching of the layer to be etched is completed, the layer located under the layer to be etched and made of a different material is exposed and starts to be etched.
In this case, the abundance ratio of the substance contained in the plasma is different from the abundance ratio of the substance when the layer to be etched is etched. That is, the values of the first and second evaluation values change before and after the end of the etching of the layer to be etched. Therefore, the end point of the etching can be detected using the first and second evaluation values. In addition, the first and second evaluation values are calculated using the emission intensity measurement values for light in three wavelength regions including the wavelengths corresponding to the substances involved in the etching process. By using the value, the end point of the etching can be detected with higher accuracy.

A plasma processing apparatus according to another aspect of the present invention is a plasma processing apparatus for performing an etching process using plasma, and includes a measuring unit, a calculating unit, and a detecting unit. The measuring means disperses light from the plasma, measures first and second emission intensities of light in the first and second wavelength ranges, respectively, and includes a first and a second wavelength ranges including the first and second wavelength ranges. The third emission intensity is measured for light in the three wavelength regions. The calculating means uses the first to third emission intensity measured values measured by the measuring means,
The ratio between the first emission intensity measurement value and the second emission intensity measurement value is calculated as a first evaluation value, and the ratio between the first emission intensity measurement value and the third emission intensity measurement value is calculated as a second evaluation value. It is calculated as an evaluation value, and the ratio between the second measured light emission intensity and the measured third light emission intensity is calculated as a third evaluated value. The detecting means sets the ratio of the first measured emission intensity and the second measured emission intensity when the etching process is completed to a first reference value, and sets the first emission intensity measurement when the etching process is completed. The ratio between the measured value and the third measured light emission intensity is used as a second reference value, and the ratio between the second measured light intensity and the measured third light intensity when the etching process is completed is defined as the third reference value. As the reference value, the first
The end of the etching process is detected using the results obtained by comparing the first to third evaluation values with the first to third reference values.

As described above, the end of the etching process can be detected with high accuracy by using the first to third evaluation values.

If the third wavelength region is set to be sufficiently wide so as to include specific wavelengths of a plurality of substances involved in the etching process, the second and third evaluation values are respectively equal to the first evaluation value.
And the concentration data in the plasma of the substance corresponding to the second wavelength region. Therefore, if the first and second wavelength regions are determined so that the specific wavelength of the substance emitted from the etching target during the etching process is included in the first and second wavelength regions, respectively, It is possible to reliably detect changes in the concentration of various substances. When the etching process is completed, the concentration of this substance in the plasma rapidly decreases, so that the end of the etching process can be easily detected.

[0028] A defective product judging method according to another aspect of the present invention is a defective product judging method in a semiconductor device manufacturing process utilizing a process using plasma, and includes a measuring process and an evaluating process. In the measuring step, the light from the plasma is dispersed to measure the first emission intensity of the light in the first wavelength region. In the evaluation step, an evaluation value using the first emission intensity measurement value measured in the measurement step is calculated, and a reference value and an evaluation value using the first emission intensity when the processing is performed normally. Then, it is determined whether or not a failure has occurred in the processing target being processed.

As described above, when the processing situation in the processing using plasma (plasma process) changes, the spectrum of the light from the plasma used in the processing changes. For this reason, the spectrum of light from the plasma differs between when the plasma process is performed normally and when a defect occurs in the processing target due to an abnormal reaction. As a result, the light from the plasma is dispersed, the first emission intensity of the light in the first wavelength region including the specific wavelength of the substance involved in the plasma process is measured, and the evaluation value is calculated as described above, By comparing with a reference value, the occurrence of a defect can be quickly detected during the plasma process.

A method for controlling a plasma processing apparatus according to still another aspect of the present invention is a method for controlling a plasma processing apparatus that performs a film forming process using plasma, and includes a measuring step and an evaluating step. In the measuring step, the light from the plasma is dispersed to measure the first emission intensity of the light in the first wavelength region. In the evaluation step, an evaluation value is calculated using a time integration value of the first emission intensity measurement value measured in the measurement step, and when the film thickness of the film formed by the film formation processing reaches a predetermined thickness. By comparing the reference value using the time integration value of the first emission intensity measurement value with the evaluation value, it is determined whether or not the film thickness of the film formed in the film forming process has reached a predetermined thickness. .

Here, as described above, there is a correlation between the film forming speed and the above-mentioned emission intensity. For this reason, there is a certain proportional relationship between the film thickness of the film formed by the film forming process and the time integration value of the emission intensity measurement value. Therefore, if the reference value is determined in advance by determining this proportional relationship by an experiment or the like, it can be easily determined whether or not the thickness of the film formed as described above has reached a predetermined thickness. If the plasma processing apparatus is controlled so as to end the film forming process when it is detected that the formed film has a predetermined thickness, the film having the predetermined thickness can be reliably formed. .

A method for controlling a plasma processing apparatus according to still another aspect of the present invention is a method for controlling a plasma processing apparatus that performs an etching process using plasma, and includes a measuring step, a calculating step, and a detecting step.
In the measurement step, the light from the plasma is dispersed to measure the first to third emission intensities of the light in the first to third wavelength ranges, respectively. In the calculation step, a ratio between the first emission intensity measurement value and the second emission intensity measurement value is calculated as a first evaluation value using the first to third emission intensity measurement values measured in the measurement step. At the same time, the ratio between the first measured light emission intensity and the third measured light intensity is calculated as a second evaluation value.
In the detection step, the ratio of the first measured emission intensity and the second measured emission intensity when the etching process is completed is set as a first reference value, and the first emission intensity measurement performed when the etching process is completed. The ratio between the measured value and the third emission intensity measurement value is defined as a second reference value, and the first and second evaluation values are defined as the first and second evaluation values.
The end of the etching process is detected by using the result of comparison with the reference values of.

Here, as described above, when the etching of the layer to be etched is completed, the layer located under the layer to be etched and made of a different material is exposed and starts to be etched. In this case, the abundance ratio of the substance contained in the plasma is different from the abundance ratio of the substance when the layer to be etched is etched. That is, the values of the first and second evaluation values change before and after the end of the etching of the layer to be etched. Therefore, the end point of the etching can be detected using the first and second evaluation values.

Further, the first and second evaluation values are calculated by using the emission intensity measurement values of the light in three wavelength regions including the wavelengths corresponding to the substances involved in the etching process. By using the two evaluation values, the end point of the etching can be detected with higher accuracy.

A method for controlling a plasma processing apparatus according to another aspect of the present invention is a method for controlling a plasma processing apparatus that performs an etching process using plasma, and includes a measuring step, a calculating step, and a detecting step. In the measuring step, the light from the plasma is separated into first and second light.
The first and second emission intensities are measured for the light in the wavelength region of, and the third emission intensity is measured for the light in the third wavelength region including the first and second wavelength regions. In the calculation step, the first emission intensity measurement value and the second emission intensity measurement value are used by using the first to third emission intensity measurement values measured in the measurement step.
Calculated as the first evaluation value of the ratio of the measured emission intensity to
The ratio between the first emission intensity measurement value and the third emission intensity measurement value is calculated as a second evaluation value, and the ratio between the second emission intensity measurement value and the third emission intensity measurement value is calculated as the third evaluation value. Is calculated as the evaluation value of In the detection step, the ratio of the first measured emission intensity and the second measured emission intensity when the etching process is completed is set as a first reference value, and the first emission intensity measurement performed when the etching process is completed. The ratio between the measured value and the third measured light emission intensity is used as a second reference value, and the ratio between the second measured light intensity and the measured third light intensity when the etching process is completed is defined as the third reference value. The end of the etching process is detected using a result obtained by comparing the first to third evaluation values with the first to third reference values, respectively, as a reference value.

As described above, the end of the etching process can be detected with high accuracy by using the first to third evaluation values.

If the third wavelength region is set to be sufficiently wide so as to include the specific wavelengths of a plurality of substances involved in the etching process, the second and third evaluation values are respectively equal to the first evaluation value.
And the concentration data in the plasma of the substance corresponding to the second wavelength region. Therefore, if the first and second wavelength regions are determined so that the specific wavelength of the substance emitted from the etching target during the etching process is included in the first and second wavelength regions, respectively, Can be reliably detected. When the etching process is completed, the concentration of the substance in the plasma rapidly decreases, so that the end of the etching process can be easily detected.

[0038]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings below, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

(Embodiment 1) FIG. 1 is a flowchart of a defective product judging method in a first embodiment of the plasma processing apparatus according to the present invention. FIG. 2 is a block diagram showing a configuration of a plasma processing apparatus that performs the defective item determination method shown in FIG. With reference to FIGS. 1 and 2, a method of determining a defective product in a plasma processing apparatus according to the present invention will be described.

Referring to FIG. 1, first, a process using plasma is performed.
Using plasma in plasma processing equipment
The process, for example, a film forming process is started (S1). this
In the film formation process, the processing room of the plasma
To convert the source gas used for film formation into plasma
By depositing a specified component on the target substrate
Form a thin film. Here, for example, on a silicon substrate
After forming a wiring layer made of aluminum, this wiring layer
Consider a case where a silicon nitride film is formed thereon. This series
Conditions for the formation of the con-nitride film include, for example,
SiH as gas _Four, NH_Three, N_TwoCan be used
Wear. In addition, the supply amount of each raw material gas is
For example, when the temperature of each gas is 0 ° C and the pressure is 1 atmosphere
And SiH _FourFlow rate of 0.1 liter / min (100 sc
cm), NH_ThreeFlow rate of 0.4 liter / min (400s
ccm), N_TwoFlow rate of 1.2 l / min (1200
sccm). In addition, 1sccm (standard
 (cubic centimeter per minute)
1cm / min gas flow at pressure^ThreeMeans
I do.

Next, in the measuring section 1 (see FIG. 2) as a measuring means, a light emission intensity measuring step (S
Perform 2). In the emission intensity measuring step (S2),
The light from the plasma is dispersed using a spectroscope or the like, and the first
The first emission intensity is measured for the light having a wavelength of 305 nm ± 3 nm as the wavelength region. This 305nm
Is a light that is detected when aluminum is present in the plasma, and is not detected when a normal film forming process is being performed. However, when high energy is locally generated in the plasma, a structure such as a wiring layer on the substrate may be damaged. In this case, aluminum, which is a constituent material of the damaged wiring layer, is released into the plasma. That is, by detecting the light having the wavelength of 305 nm, it is possible to detect whether or not the wiring layer on the substrate is damaged.

Next, the arithmetic unit 2 (see FIG. 2) as the evaluation means uses the emission intensity data for the light of 305 nm ± 3 nm as the first emission intensity measurement value measured by the measurement unit 1. An evaluation value (evaluation data) is calculated (S3). Here, the emission intensity data is used as it is as the evaluation value.

Next, the arithmetic unit 2 compares the evaluation value with the reference value, which is the value of the above-mentioned evaluation value when the film forming process is performed normally, so that the defect in the processing target being processed is determined. It is determined whether or not an error has occurred (S
4). Here, when the normal film forming process is performed as described above, the light having the wavelength of 305 nm is hardly detected, so that the reference value is set to a very low value.

When the evaluation value satisfies the reference value,
That is, when light having a wavelength of 305 nm is hardly detected, it is determined that no defective product has occurred (S5). Conversely, when the evaluation value does not satisfy the reference value, that is, when light having a wavelength of 305 nm is detected at a value exceeding the reference value, it is determined that a defective product has occurred (S6). Then, the data of these determination results is transmitted to the control unit 3 (see FIG. 2), and processing such as generating an alarm for notifying the operator of the occurrence of a defect is performed.

As described above, according to the present invention, the occurrence of a defect can be quickly detected during the plasma process. When another material such as tantalum (Ta) is used as the material of the wiring layer, the wavelength of light measured when Ta is present in the plasma is 301 nm.
Therefore, the wavelength is 301 as the first emission intensity measurement value.
The emission intensity data for light having a wavelength of nm ± 3 nm may be used.

In the measuring section 1, the wavelength 405n is used as the first wavelength region instead of the wavelength 305nm.
The first emission intensity of the light having a wavelength of m ± 3 nm is measured, and 414 nm ± 3n as a second wavelength region is measured.
Means may be provided for measuring the second emission intensity for the light of m. Here, light having a wavelength of 405 nm is light detected when SiN is present in the plasma, and light having a wavelength of 414 nm is light detected when silicon hydride (SiH) is present in the plasma. . Both SiN and SiH are substances involved in the process of forming a silicon nitride film. Then, the arithmetic unit 2 may calculate a ratio between the second measured light emission intensity and the measured first light emission intensity measured by the measuring unit 1 as an evaluation value. In addition, an evaluation value, which is a ratio of the second emission intensity measurement value and the first emission intensity measurement value when the film forming process is performed normally, may be used as the reference value.
In this case, for example, a value of about 1/6 can be used as a reference value when (second light emission intensity measurement value) / (first light emission intensity measurement value) is used as the evaluation value.

In the silicon nitride film formation reaction, when a normal reaction is occurring, the ratio of SiN and SiH, which are substances involved in the reaction, in the plasma exhibits a substantially constant predetermined value. If the absolute value of the measured light emission intensity of the light corresponding to SiN or SiH fluctuates due to a change in conditions such as the film formation rate, although a normal reaction occurs, the abundance ratio is calculated based on the change in the absolute value. Is relatively small. For this reason, the ratio between the second emission intensity measurement value and the first emission intensity measurement value (the ratio between the emission intensity measurement value of light corresponding to SiN and the emission intensity measurement value of light corresponding to SiH) is evaluated as an evaluation value. When used as, it is possible to suppress a decrease in the accuracy of defective product determination due to a change in the absolute value of the emission intensity measurement value, so that the occurrence of defective products can be detected with higher accuracy. Further, the measuring unit 1 has a wavelength of 405 nm ± as the first wavelength range.
There may be provided a means for measuring the broad-band emission intensity of light having a wavelength range of 250 nm to 900 nm, which includes a wavelength range of 3 nm and is wider than the first wavelength range. Then, the emission intensity measuring step (S
In 2), the broad-band emission intensity in the wide-band wavelength range may be measured. In addition, the arithmetic unit 2 uses, as another evaluation value, the ratio of the first emission intensity measurement value (the emission intensity measurement value of light having a wavelength of 405 nm ± 3 nm) to the measurement value of the wide-area emission intensity measured by the measurement unit 1. It may be calculated.
Then, using the value of the other evaluation value when the film forming process is performed normally as another reference value, another result of comparing the other evaluation value with the other reference value, and the evaluation value and the reference value The result of the comparison with the value may be used to determine whether a failure has occurred in the processing target.

In this case, the broad-band emission intensity (250 nm to 9
Broad-band emission intensity for light in the wavelength range of 00 nm)
The measured values are measured in a wide wavelength region (250 nm to 900 nm).
nm) in the plasma. The wide wavelength region is set so as to substantially cover the wavelength of light from a substance involved in a silicon nitride film formation reaction. According to this configuration, the other evaluation value is SiN which is a substance corresponding to the first wavelength region.
Abundance ratios of the above-mentioned plural kinds of substances in the plasma. When an abnormal reaction occurs, it is considered that such an abundance ratio of SiN also fluctuates. Therefore, if the above other evaluation values are used, occurrence of a defect can be detected with higher accuracy. When the evaluation value is compared with the reference value as described above, for example, when the evaluation value deviates from the reference value by ± 10% or more, it can be determined that a failure has occurred. The allowable amount of the deviation from the reference value is determined in advance by performing a test to determine the relationship between the deviation from the reference value and the defect occurrence rate, and from this relationship, a predetermined defect occurrence rate can be achieved. Is determined. For example, the defect occurrence rate when the deviation from the reference value is 5% is 0.3%, the defect occurrence rate when the deviation is 10% is 3%, and the defect occurrence rate when the deviation from the reference value is 20%. Is 15%, the defect rate is 0.3%.
In the case of%, the criterion for determining the deviation from the reference value is determined to be 5%.

(Embodiment 2) FIG. 3 is a flowchart of a control method for a plasma processing apparatus according to Embodiment 2 of the present invention. With reference to FIG. 3, a control method of the plasma processing apparatus will be described. The configuration of the plasma processing apparatus according to the second embodiment of the present invention is basically the same as that of the first embodiment of the present invention shown in FIG.

Referring to FIG. 3, first, a film formation process as a process using plasma is started in a plasma processing apparatus for performing a process using plasma (S1). In this film forming process, a case where a silicon nitride film is formed as in the first embodiment will be considered. The process conditions of this film forming process are as follows:
Basically, the process conditions are the same as those in the first embodiment.

Next, in the measuring section 1 (see FIG. 2) as a measuring means, a light emission intensity measuring step (S
Perform 7). In this emission intensity measuring step (S7),
The light from the plasma is separated to measure the first emission intensity of the light having a wavelength of 405 nm ± 3 nm as the first wavelength range, and to measure the first emission intensity of the light as the second wavelength range.
The second emission intensity of the light having a wavelength of 14 nm ± 3 nm is measured. Here, the light from the plasma has a spectrum as shown in FIG. FIG. 4 is a graph showing the relationship between the wavelength of light from plasma and the emission intensity. Then, among the lights having various wavelengths, as described above, 405 nm
Is light detected when SiN is present in the plasma, and light having a wavelength of 414 nm is light detected when a substance called silicon hydride (SiH) is present in the plasma. Both SiN and SiH are substances involved in the process of forming a silicon nitride film.

Next, in the calculation section 2 (see FIG. 2) as an evaluation means, first, the emission intensity integration step (S
8) is performed. Specifically, the measured values of the first and second emission intensities are added to calculate an intermediate evaluation value.

Next, the arithmetic unit 2 integrates the intermediate evaluation value with time (S9). As shown in FIG. 5, the value obtained by this time integration (time integrated value) is the hatched area in FIG. 5 with respect to the measured values of the first and second emission intensities after the film formation process is started. It corresponds to the area of the region that has been set. FIG. 5 is a graph showing the relationship between the sum of the first and second emission intensity measurement values and time. This time integration value is set as an evaluation value. Here, there is a correlation between the deposition rate of the silicon nitride film and the concentrations of SiN and SiH, which are substances in the plasma involved in the deposition reaction. Then, the concentrations of SiN and SiH involved in the film forming reaction and the wavelengths (405 nm, 414 nm) corresponding to the SiN and SiH are used.
Since the first and second luminous intensities, which are the luminous intensities of light in the wavelength region including m), have a correlation, the film formation rate has a correlation with the first and second luminous intensities. . For this reason, there is a certain proportional relationship between the thickness of the film formed by the film forming process and the above evaluation value.

Next, the arithmetic unit 2 compares a reference value, which is the value of the evaluation value when the film thickness of the silicon nitride film formed by the film forming process has reached a predetermined film thickness, with the evaluation value. (S10). As described above, if the reference value is determined in advance by determining the proportional relationship between the film thickness of the silicon nitride film formed by the film forming process and the above-described evaluation value by experiments or the like, the film thickness of the silicon nitride film becomes a predetermined value. It can be easily determined whether or not the film thickness has been reached.

When the evaluation value becomes equal to or more than the reference value, a signal is transmitted to the control unit 3 so as to end the film forming process. Thus, the film forming process ends (S11).

In this way, a silicon nitride film having a predetermined thickness can be reliably formed.

When the first and second emission intensity measurement values for a plurality of wavelength regions are used as described above, the thickness of the formed silicon nitride film is smaller than when only data for one wavelength region is used. Whether or not the thickness has reached the predetermined thickness can be determined with higher accuracy.

Further, the measuring section 1 has means for measuring the broad-band emission intensity of the light in the wavelength range of 350 nm to 900 nm, which includes the first wavelength range and is wider than the first wavelength range. It may be. In the emission intensity measuring step (S7), the above-mentioned wide-range emission intensity may be measured. The calculation unit 2 may use the ratio of the time integrated value of the wide-area emission intensity measurement value measured by the measurement unit 1 to the time integration value of the first emission intensity measurement value as the evaluation value.

In this case, the measured value of the broad-band emission intensity is obtained by integrating the emission intensity for each wavelength with respect to the spectrum shown in FIG. That is, the measured value of the broad-band emission intensity reflects the concentrations of a plurality of substances involved in the silicon nitride film formation processing. Therefore, similarly to the first emission intensity measurement value (the emission intensity measurement value of light having a wavelength of 405 nm for SiN), the film thickness of the silicon nitride film formed by the film forming process and the wide-area emission intensity measurement value It is considered that there is a certain proportional relationship with the time integral value. As a result, the evaluation value is calculated by using both the time integration value of the wide-range emission intensity measurement value and the time integration value of the first emission intensity measurement value,
It is possible to control the thickness of the silicon nitride film with higher accuracy.

In the second embodiment, the luminous intensity is measured in two wavelength regions. However, only one of the first luminous intensity and the second luminous intensity may be used. . In this case, substantially the same effect can be obtained.

The first wavelength region is 350 nm
A wide wavelength range of up to 900 nm may be employed.

(Embodiment 3) FIG. 6 is a flowchart of a control method for a plasma processing apparatus according to a third embodiment of the present invention. With reference to FIG. 6, a control method of the plasma processing apparatus will be described. The configuration of the plasma processing apparatus according to the third embodiment of the present invention is basically the same as that of the first embodiment of the present invention shown in FIG.

Referring to FIG. 6, first, an etching process as a process using plasma is started in a plasma processing apparatus for performing a process using plasma (S1).
In this etching process, the silicon nitride film is etched using plasma using a fluorine-based etching gas. The process conditions of this etching process include, for example, CF ₄ , C ₂ F ₆ , SF ₆ , N
Or the like can be used F _3.

Next, in the measuring section 1 (see FIG. 2) as a measuring means, a light emission intensity measuring step (S
Perform 7). In this emission intensity measuring step (S7),
The light from the plasma is separated into light having a first emission intensity of light having a wavelength of 704 nm ± 3 nm as a first wavelength region and a wavelength of 763 nm ± 3 as a second wavelength region.
The second emission intensity for light having a wavelength of nm and the third emission intensity for light having a wavelength of 891 nm ± 3 nm as a third wavelength region are measured. Light having a wavelength of 704 nm is light detected when fluorine (F) is present in plasma, and light having wavelengths of 763 nm and 891 nm is light detected when nitrogen is present in plasma.

Next, the calculation section 2 (see FIG. 2) as calculation means calculates first and second evaluation values representing the abundance ratio of fluorine and nitrogen in the plasma (S12). Specifically, the second emission intensity measurement value (wavelength is 763 nm ±
The first emission intensity measurement value (wavelength is 704 nm ± 3n) relative to the second emission intensity measurement value for light having a wavelength of 3 nm.
The ratio of (the measured value of the first light emission intensity) of the light of m is calculated as the first evaluation value. Further, a ratio of the first emission intensity measurement value to the third emission intensity measurement value (third emission intensity measurement value for light having a wavelength of 891 nm ± 3 nm) is calculated as a second evaluation value. Here, as shown in FIG. 7, the first and second evaluation values are about 1/5 when the silicon nitride film is etched (the second and third emission intensities are lower than the first and second emission intensities). 1). FIG. 7 is a graph showing relative values of the first to third emission intensities when the silicon nitride film is etched. However, when the etching of the silicon nitride film is completed, as shown in FIG. 8, the first emission intensity is higher than the second and third emission intensity. And the first in this case
Is 7/4, and the value of the second evaluation value is about 7. FIG. 8 is a graph showing relative values of the first to third emission intensities at the time when the etching of the silicon nitride film is completed. That is, as shown in FIG. 9, the first to third emission intensities change with time during the etching of the silicon nitride film. When the etching of the silicon nitride film is completed, the values of the first to third emission intensities are different from those when the silicon nitride film is etched as described above. FIG. 9 is a graph showing a change with time of the first to third emission intensities during the etching process of the silicon nitride film.

Next, the first and second evaluation values are converted into the first and second evaluation values when the etching process is completed by the arithmetic unit 2 which is also the detecting means. Each is compared with a reference value (S13). Here, the first reference value is set to 7/4, and the second reference value is set to 7. Then, as a result of the comparison, the first and second
When the evaluation values of the above are respectively equal to or larger than the first and second reference values, it is determined that the etching process is completed, and the information is transmitted to the control unit 3 (see FIG. 2). The control unit 3 controls each device of the plasma processing apparatus to end the etching process (S11).

As described above, the values of the first and second evaluation values change before and after the end of the etching of the silicon nitride film to be etched as shown in FIGS. Therefore, the end point of the etching can be easily detected using the first and second evaluation values. Also, like this
By using one evaluation value, the end point of etching can be detected with higher accuracy than when one evaluation value is used.

In the third embodiment of the present invention, a wider wavelength range including 704 nm and 763 nm is selected as the third wavelength range, and the third wavelength range is selected in the emission intensity measuring step (S 7). May be measured. Then, the arithmetic unit 2 may calculate, as the second evaluation value, the ratio of the first emission intensity measurement value to the third emission intensity measurement value as the second evaluation value. Further, a ratio of the second emission intensity measurement value to the third emission intensity measurement value may be calculated as the third evaluation value. The calculation unit 2 may compare the first to third evaluation values with first to third reference values, which are the values of the first to third evaluation values when the etching process is completed. In this case, the first evaluation value increases as described above when the etching is completed.
Further, the second evaluation value increases with an increase in the concentration of fluorine when the etching is completed. Further, the third evaluation value decreases as the concentration of nitrogen decreases after the etching is completed.

As described above, the end of the etching process can be detected with higher accuracy by using the first to third evaluation values.

Note that the reference value may be changed and set for each plasma processing apparatus in order to reflect the variation for each plasma processing apparatus.

In the above embodiment, the first to third
Are set to (nm) (measurement target wavelength) ± (measurement range wavelength width), the measurement range wavelength width is set to 3 nm. However, the measurement range wavelength width may be a value other than 3 nm. .

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the embodiments described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0073]

According to the present invention, a plasma processing apparatus and a plasma processing apparatus capable of controlling a film forming process with high accuracy by using emission intensity data obtained by dispersing light from plasma in plasma processing. It is possible to provide a control method, a plasma process apparatus capable of detecting occurrence of defective products, a defective product determination method, a plasma process apparatus capable of detecting the end point of the etching process with high accuracy, and a control method thereof.

[Brief description of the drawings]

FIG. 1 is a flowchart of a defective product determination method in a first embodiment of a plasma processing apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a plasma processing apparatus that performs the defective item determination method illustrated in FIG.

FIG. 3 is a flowchart of a control method of a plasma processing apparatus in a second embodiment of the plasma processing apparatus according to the present invention.

FIG. 4 is a graph showing a relationship between a wavelength of light from plasma and an emission intensity.

FIG. 5 is a graph showing a relationship between an added value of the first and second emission intensity measurement values and time.

FIG. 6 is a flowchart of a control method for a plasma processing apparatus in a third embodiment of the plasma processing apparatus according to the present invention.

FIG. 7 is a graph showing relative values of first to third emission intensities when a silicon nitride film is etched.

FIG. 8 is a graph showing relative values of first to third emission intensities at the time when etching of a silicon nitride film is completed.

FIG. 9 shows a first example of a silicon nitride film etching process.
7 is a graph showing a change with time of a third light emission intensity.

[Explanation of symbols]

 1 Measurement unit, 2 calculation unit, 3 control unit.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // G01N 21/73 H01L 21/302 EF term (reference) 2G043 AA03 EA08 JA01 KA01 KA02 KA03 4K030 AA06 AA13 AA18 BA40 DA04 DA08 FA01 HA16 JA01 KA36 KA39 KA41 4K057 DA11 DA14 DB06 DB20 DD01 DJ02 DM40 DN01 5F004 AA16 CB02 CB15 DA01 DA02 DA17 DA18 DB07 5F045 AA08 AB33 AC01 AC12 AC15 GB08

Claims (12)

[Claims] 1. A plasma processing apparatus for performing a process using plasma, comprising: a measuring unit configured to spectrally separate light from plasma to measure a first emission intensity of light in a first wavelength region; Calculating an evaluation value using the first emission intensity measurement value measured by the means, and comparing a reference value using the first emission intensity with the evaluation value when the processing is performed normally; And a evaluating means for determining whether or not a defect has occurred in the processing target being processed. 2. The measuring means has means for measuring a second emission intensity of light in a second wavelength range that is a wavelength range different from the first wavelength range. Calculating a ratio between the second emission intensity measurement value measured by the measurement means and the first emission intensity measurement value as the evaluation value; and calculating the second emission intensity when the processing is performed normally. The plasma processing apparatus according to claim 1, wherein a ratio between an intensity measurement value and the first emission intensity measurement value is set as the reference value. 3. The measuring means includes means for measuring a wide-band emission intensity for light in a wide-band wavelength region that includes the first wavelength region and is wider than the first wavelength region. The ratio of the first luminescence intensity measurement value to the wide luminescence intensity measurement value measured by the measurement means is calculated as another evaluation value, and the ratio is calculated for the wide luminescence intensity measurement value when the processing is performed normally. Using the ratio of the first emission intensity measurement value as another reference value, another result of comparing the other evaluation value with the other reference value, and a result of comparing the evaluation value with the reference value. 3. The plasma processing apparatus according to claim 2, wherein whether or not a defect has occurred in the processing target is determined using the method. 4. The measuring means includes a means for measuring a wide-band emission intensity of light in a wide-band wavelength region that includes the first wavelength region and is wider than the first wavelength region. The plasma processing apparatus according to claim 1, wherein a ratio of the first emission intensity measurement value to a wide-area emission intensity measurement value measured by the measurement unit is calculated as the evaluation value. 5. A plasma processing apparatus for performing a film forming process using plasma, comprising: a measuring unit that disperses light from the plasma to measure a first emission intensity of light in a first wavelength region; An evaluation value is calculated using a time integration value of the first emission intensity measurement value measured by the measurement unit, and the evaluation value when the film thickness of the film formed by the film formation processing reaches a predetermined thickness is calculated. By comparing a reference value using a time integration value of the first emission intensity measurement value with the evaluation value, it is determined whether or not the film thickness of the film formed in the film forming process has reached a predetermined thickness. A plasma processing apparatus comprising: 6. The measuring unit includes a unit that measures a second emission intensity of light in a second wavelength region that is a wavelength region different from the first wavelength region. 6. The plasma process according to claim 5, wherein the evaluation value is calculated using a time integration value of a second emission intensity measurement value measured by the measurement unit and a time integration value of the first emission intensity measurement value. apparatus. 7. A plasma processing apparatus for performing an etching process using plasma, wherein the light from the plasma is separated to obtain first to third emission intensities for light in first to third wavelength ranges, respectively. And measuring the ratio between the first emission intensity measurement value and the second emission intensity measurement value using the first to third emission intensity measurement values measured by the measurement means. Calculating means for calculating the ratio of the first measured luminescence intensity and the third measured luminescence intensity as a second evaluation value, and calculating the ratio as a second evaluation value; The ratio between the first emission intensity measurement value and the second emission intensity measurement value is set as a first reference value, and the first emission intensity measurement value and the third emission intensity when the etching process is completed. The ratio with the measured intensity value is used as a second reference value, The first and second evaluation values are:
A plasma processing apparatus comprising: a detection unit configured to detect an end of the etching process using a result of comparison with the first and second reference values. 8. A plasma processing apparatus for performing an etching process using plasma, wherein the light from the plasma is separated and the first and second emission intensities of the light in the first and second wavelength ranges are respectively reduced. Measuring and including a third wavelength region including the first and second wavelength regions.
Measuring means for measuring a third emission intensity for light in a wavelength range of: using the first to third emission intensity measurement values measured by the measurement means, the first emission intensity measurement value and the Calculating a ratio between the second emission intensity measurement value and the first emission intensity measurement value, and calculating a ratio between the first emission intensity measurement value and the third emission intensity measurement value as a second evaluation value; Calculating means for calculating a ratio of the second measured light emission intensity to the third measured light emission intensity as a third evaluation value; and the first measured light emission intensity when the etching process is completed. And the ratio of the second emission intensity measurement value to the first emission intensity measurement value is a first reference value, and the ratio between the first emission intensity measurement value and the third emission intensity measurement value when the etching process is completed is the second reference value. 2, and the second emission intensity when the etching process is completed. Using the ratio between the constant value and the third emission intensity measurement value as a third reference value, using the results of comparing the first to third evaluation values with the first to third reference values, respectively, A plasma processing apparatus comprising: a detection unit configured to detect completion of the etching process. 9. A method for determining a defective product in a manufacturing process of a semiconductor device using a process using plasma, wherein light from the plasma is dispersed to reduce a first emission intensity of light in a first wavelength region. A measuring step of measuring, and calculating an evaluation value using the first emission intensity measurement value measured in the measurement step, and a reference using the first emission intensity when the processing is performed normally. An evaluation step of determining whether a defect has occurred in the processing target being processed by comparing the value with the evaluation value. 10. A method for controlling a plasma processing apparatus for performing a film forming process using plasma, comprising: dispersing light from plasma to measure a first emission intensity of light in a first wavelength region. And calculating an evaluation value using a time integration value of the first emission intensity measurement value measured in the measurement step, and a film thickness of the film formed by the film formation processing has reached a predetermined thickness. The first of time
An evaluation for determining whether or not the film thickness of the film formed in the film forming process has reached a predetermined film thickness by comparing a reference value using a time integration value of the measured light emission intensity with the evaluation value. And a method for controlling a plasma processing apparatus. 11. A method for controlling a plasma processing apparatus for performing an etching process using plasma, comprising: separating light from the plasma to obtain first to third wavelengths of light in first to third wavelength ranges; A measuring step of measuring the luminous intensity of the first and third luminous intensity measured using the first to third luminous intensity measured in the measuring step, the first luminous intensity measured value and the second luminous intensity measured value Calculating the ratio of the first emission intensity measurement value and the third emission intensity measurement value as a second evaluation value, and calculating the ratio of the first emission intensity measurement value and the third emission intensity measurement value as a second evaluation value. The ratio between the first emission intensity measurement value and the second emission intensity measurement value when the etching process is completed is set as a first reference value, and the first emission intensity measurement value when the etching process is completed and the The ratio of the third emission intensity measurement value to the second emission intensity As a reference value, the first and second evaluation values are:
A detection step of detecting the end of the etching process using a result of comparison with the first and second reference values, respectively. 12. A method for controlling a plasma processing apparatus for performing an etching process using plasma, comprising separating light from the plasma into first and second wavelengths of light in first and second wavelength ranges, respectively. Measuring a luminous intensity and including a third wavelength including the first and second wavelength ranges;
For the light in the wavelength region, a measurement step of measuring a third emission intensity, and using the first to third emission intensity measurement values measured in the measurement step, the first emission intensity measurement value and The ratio between the second emission intensity measurement value and the third emission intensity measurement value is calculated as a first evaluation value, and the ratio between the first emission intensity measurement value and the third emission intensity measurement value is calculated as a second evaluation value. An arithmetic step of calculating a ratio of the second measured light emission intensity to the third measured light intensity as a third evaluation value; and the first measured light emission when the etching process is completed. The ratio between the measured value of the second emission intensity and the measured value of the second emission intensity is defined as a first reference value, and the ratio between the measured value of the first emission intensity and the measured value of the third emission intensity when the etching process is completed. A second reference value, and the second light emission when the etching process is completed. The ratio between the measured intensity value and the third emission intensity measured value is used as a third reference value, and the results of comparing the first to third evaluation values with the first to third reference values are used. And a detecting step of detecting the end of the etching process.