JP2003188150A - Semiconductor process monitoring method and semiconductor process monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for monitoring a semiconductor process by which measurement of the thickness or the like of a film formed on a semiconductor substrate can be easily performed in a nondestructive manner and to provide a monitoring system. <P>SOLUTION: With respect to the semiconductor process monitoring method by which the thickness of a semiconductor substrate is processed by a plasma, the correlation between the physical quantity of the plasma necessary for the plasma processing and the variation in the thickness of a semiconductor substrate 8 to be processed is previously obtained. When the semiconductor substrate 8 is subjected to a plasma processing, the physical quantity of the plasma during the plasma processing is measured and the variation in the thickness or the thickness of the semiconductor substrate 8 is calculated according to the correlation. The plasma processing is completed when the thickness of the semiconductor substrate 8 reaches the desired thickness. <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 semiconductor process monitoring method and a semiconductor process monitoring apparatus for inspecting a thickness processing state of a semiconductor substrate in a semiconductor element manufacturing process, for example.

[0002]

2. Description of the Related Art As a conventional semiconductor process monitoring method, for example, a method of measuring the film thickness of an oxide film or the like formed on a semiconductor substrate using an optical method, X-ray, infrared ray, etc., a micrometer or an SEM is used. (Scanning electron microscope, Scannin
There is a method of directly observing the cross-sectional structure of the semiconductor substrate using g Electron Microscope) and measuring the film thickness of an oxide film or the like formed on the semiconductor substrate.

In the optical measuring method, a semiconductor substrate which is a sample to be inspected is irradiated with light, and a reflected wave from the semiconductor substrate is analyzed based on a refractive index of light and the like, and a film such as an oxide film on the semiconductor substrate is analyzed. It measures the thickness.

In addition, the measuring method using infrared rays is to irradiate infrared rays from one side of the semiconductor substrate and measure the intensity of the infrared rays passing through the semiconductor substrate from the other side to obtain an oxide film formed on the semiconductor substrate. The film thickness is measured. The measuring method using X-rays also measures the film thickness of an oxide film or the like formed on a semiconductor substrate, similarly to the measuring method using infrared rays.

[0005]

However, in the semiconductor process monitoring method as described above, since the measurement method focuses on light reflection, infrared ray, and X-ray transmission, it is complicated to cover multiple layers on the semiconductor substrate. Film (deposited film)
In the case of forming a film, since light is scattered, it is difficult to measure the thickness of each film forming the deposited film.

Further, in the semiconductor process monitoring method using infrared rays and X-rays as described above, infrared rays,
For a deposited film having a thickness that does not transmit X-rays, there is a problem that it is impossible to measure the film thickness formed on the semiconductor substrate.

Further, when the cross-sectional structure of the semiconductor substrate is observed by using a micrometer or SEM, the cross-section is cut out and measured, so that the film thickness formed on the semiconductor substrate cannot be measured nondestructively. There was a problem.

The present invention has been made to solve the above problems, and a semiconductor process monitoring method and a semiconductor process monitoring apparatus capable of easily and nondestructively measuring a film thickness or the like formed on a semiconductor substrate. It is intended to provide.

[0009]

According to a first aspect of the present invention, there is provided a semiconductor process monitoring method for performing a thickness processing of a semiconductor substrate using plasma, wherein the physical quantity of plasma required for plasma processing and the processing The correlation with the thickness of the target semiconductor substrate 8 or the amount of change in thickness is obtained in advance, and when the semiconductor substrate 8 is subjected to plasma processing, the physical quantity of plasma during plasma processing is measured, and based on the correlation. The amount of change in the thickness of the semiconductor substrate 8 or the amount of thickness is calculated, and the plasma treatment is terminated when the thickness of the semiconductor substrate 8 reaches a desired thickness.

A semiconductor process monitoring method according to a second aspect of the present invention is characterized in that, in the invention according to the first aspect, the physical quantity of the plasma is impedance of the plasma.

Further, a semiconductor process monitoring method according to a third aspect is characterized in that, in the invention according to the first aspect, the physical quantity of the plasma includes at least an emission spectrum intensity and a wavelength of the plasma. It is a thing.

The semiconductor process monitoring apparatus according to a fourth aspect of the present invention is a chamber 1 having a pair of electrodes 7 therein, a high frequency power source 2 for applying a high frequency voltage or high frequency power, and the high frequency power source 2. When the impedance of the semiconductor substrate 8 itself deviates from the characteristic impedance of 1., the impedance adjuster 3 that adjusts the impedance of the semiconductor substrate 8 to match the characteristic impedance and optimizes it, and the plasma physical quantity measurement that measures the physical quantity of plasma And a high-frequency voltage between the pair of electrodes 7 by the high-frequency power source 2 by electrically connecting the pair of electrodes 7 and the high-frequency power source 2 via the impedance adjuster 3. Alternatively, plasma is generated by applying high frequency power, and the plasma physical quantity measuring device 4 is used.
Through measurement of the physical quantity of plasma in the chamber 1 according to any one of claims 3 to 3, the amount of change in the thickness of the semiconductor substrate 8 provided on one electrode of the pair of electrodes 7 or It is characterized in that the amount of thickness is calculated.

Further, in the semiconductor process monitoring method according to a fifth aspect, in the invention according to the fourth aspect, the plasma physical quantity measuring device 4 includes a measuring terminal 41 connected to each of the pair of electrodes 7. The impedance measuring device 4a has a function of measuring the impedance of the plasma generated between the pair of electrodes 7 by using the measuring terminal 41.

Further, in the semiconductor process monitoring method according to a sixth aspect, in the invention according to the fourth aspect, the plasma physical quantity measuring device 4 receives the plasma light generated between the pair of electrodes 7. An emission spectrum measuring instrument 4b having a function of measuring an emission spectrum intensity and a wavelength of plasma generated between the pair of electrodes 7 in the light receiving section 42. is there.

The semiconductor process monitoring method according to claim 7 is the method according to claim 4, wherein a capacitor 43 is provided between the chamber 1 and the impedance adjuster 3, and the plasma physical quantity measuring device 4 is provided. But,
The voltage across the capacitor 43 is measured to measure the voltage of the capacitor 4
3 is a charge amount measuring device 4c having a function of calculating the amount of charge accumulated in No. 3.

The semiconductor process monitoring method according to claim 8 is the method according to any one of claims 4 to 7, wherein the plasma physical quantity measuring device 4 is
It is characterized in that it is housed in a shielding case 5 made of a conductive material having an electromagnetic shielding property, and the shielding case 5 is connected to the ground.

Here, the physical quantity of the above plasma includes the impedance of the plasma generated between the pair of electrodes 7 in the chamber 1, the emission spectrum intensity and wavelength of the plasma generated and generated at the time of radical generation, and the plasma. It includes the amount of ions and electrons distributed inside, the amount of charge corresponding to changes in plasma, the type of active species such as radicals, and the like.

[0018]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram showing a semiconductor process monitoring apparatus according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram showing a semiconductor substrate 8 and a cross-sectional view of a cell 81 constituting the semiconductor substrate 8.

In the semiconductor process monitoring method, the correlation between the physical quantity of plasma required for plasma processing and the thickness of the semiconductor substrate 8 to be processed or the amount of change in thickness is obtained in advance and the semiconductor substrate 8 is subjected to plasma processing. ,
The physical quantity of plasma during the plasma processing is measured by a semiconductor process monitoring device described later, and based on the correlation obtained in advance, the amount of change in the thickness of the semiconductor substrate 8 or the amount of thickness is calculated to obtain the desired thickness of the semiconductor substrate 8. When the thickness is reached, the plasma processing is finished.

Here, in the first embodiment, the above-mentioned physical quantity of plasma is calculated from the resistance component, the capacitance component and the reactance component of the plasma generated between the pair of electrodes 7 in the chamber 1 as described later. What can be used to calculate the thickness of the semiconductor substrate 8 by using possible impedances is shown.

First, the semiconductor process monitoring apparatus performs a semiconductor process and has a chamber 1 having a pair of electrodes 7 therein, a high frequency power source 2 for applying a high frequency voltage or high frequency power, and characteristics of the high frequency power source 2. An impedance adjuster 3 that adjusts the impedance of the semiconductor substrate 8 so as to match the characteristic impedance when the impedance of the semiconductor substrate 8 itself deviates from the impedance, and a plasma physical quantity measuring device 4 that measures the physical quantity of plasma. And an impedance measuring instrument 4a.

The chamber 1 is made of a conductive material having an electromagnetic shield, and has a closed space inside, and a pair of opposing electrodes 7 made of stainless steel, for example, are arranged in the closed space.

The pair of electrodes 7 are electrically connected to the impedance adjuster 3 by a cable or the like, and the impedance adjuster 3 is electrically connected to the high frequency power source 2 by a cable or the like.

The impedance measuring instrument 4a is housed in a shielding case 5 made of a conductive material having an electromagnetic shield from the outside and provided with two measuring terminals 41.
One measuring terminal 41 is connected to each of the pair of electrodes 7 provided inside the chamber 1, and has a function of measuring a current and a voltage flowing between the pair of electrodes 7. The impedance is calculated from the measurement result.

The shielding case 5 as shown in FIG.
Connect to earth. With such a configuration, the impedance measuring device 4a can measure the impedance accurately without being affected by noise or the like.

In addition, the impedance measuring instrument 4a uses one of the semiconductor substrates 8 to be described later, which is a target of the plasma processing, as a sample, for example, and correlates the impedance and the thickness of a desired portion of the semiconductor substrate 8 in advance. I ask for it.

Then, by utilizing the correlation between this impedance and the thickness of the desired portion of the semiconductor substrate 8, the thickness of the desired portion of the semiconductor substrate 8 is calculated from the impedance calculated by the impedance measuring device 4a. .

Here, the semiconductor substrate 8 to be plasma-treated by the semiconductor process monitoring apparatus can be divided into a plurality of cells 81, as shown in FIG. As shown in FIG. 2 (b), for example, deposited films of SiO ₂ and SiNO ₂ are formed on the silicon wafer 8a.
Etc., an oxide film 8b is formed, and a resist 8c serving as a mask is applied on the oxide film 8b. The resist 8c is applied to a portion other than the oxide film 8b to be plasma-treated.

In the first embodiment, the thickness of the desired portion of the semiconductor substrate 8 is, for example, the thickness of the portion of the semiconductor substrate 8 where the resist 8c is not applied.

The semiconductor process monitoring method will be described below with reference to FIGS. 1 and 2. First, the semiconductor substrate 8 as shown in FIG. 2A to be subjected to the plasma treatment is made so that the surface of the silicon wafer 8a which is not the resist 8c is in contact with, for example, the lower electrode 7 of the pair of electrodes 7 in the chamber 1. Deploy. That is, the lower electrode 7 also serves as a stage of the semiconductor substrate 8.

Then, a high frequency voltage of, for example, 13.56 MHz is applied from the high frequency power source 2 through the impedance adjuster 3 to generate plasma between the pair of electrodes 7 in the chamber 1. Here, 6 in FIG. 1 schematically shows a plasma region generated between the pair of electrodes 7.

Oxide film 8 not coated with resist 8c
2b by exposing the surface of FIG.
As shown in (c), the oxide film 8b of the semiconductor substrate 8 is etched to form an etched portion in the opening 8d.

Then, in the impedance measuring device 4a,
The impedance is calculated from the plasma generated between the pair of electrodes 7, and the thickness of the oxide film 8b remaining below the opening 8d is calculated from this impedance and the previously obtained correlation described above. Then, when the desired thickness of the oxide film 8b is achieved, the application of the high frequency power supply 2 is terminated.

In the semiconductor process monitoring method and the semiconductor process monitoring apparatus, the impedance, which is the physical quantity of the plasma required for the plasma processing, is measured to obtain the impedance and the thickness of the desired portion of the semiconductor substrate 8 which are obtained in advance. Using the correlation of
The thickness of the desired portion of the semiconductor substrate 8 is calculated, and the plasma processing is terminated when the thickness of the semiconductor substrate 8 reaches the desired thickness, but it does not utilize the transparency of infrared rays, X-rays, etc. as in the conventional case. Therefore, when a complicated film (deposited film) that extends over multiple layers where light scattering is a problem is formed on the semiconductor substrate 8, or a deposited film having a thickness that does not transmit infrared rays or X-rays is formed on the semiconductor substrate 8. Even when it is formed, the film thickness and the like formed on the semiconductor substrate 8 can be easily measured nondestructively. Further, the film thickness formed on the semiconductor substrate 8 is
Since it is measured inline during the semiconductor process, there is no need to interrupt the process and work efficiency is good.

In the first embodiment, the thickness of a desired portion of the semiconductor substrate 8 is used as the target for obtaining the correlation with the physical quantity of plasma, but in addition to this, the variation of the thickness of the semiconductor substrate 8 is used. May be used.

Further, in the first embodiment, the physical quantity of plasma is used as the target of the correlation, which is obtained in advance. However, the change amount of the physical quantity of plasma is used as the target of the correlation, and the change amount of the physical quantity of plasma is The correlation with the thickness of the semiconductor substrate 8 to be processed or the variation amount of the thickness is obtained in advance, and the semiconductor substrate 8 is calculated from the variation amount of the physical quantity of plasma.
The thickness or the amount of change in thickness may be obtained.

The high-frequency voltage or high-frequency power applied by the high-frequency power source 2 is 10 MHz or more and 50 GHz or less, so that impedance measurement can be performed with high accuracy without destruction of the semiconductor substrate 8 to be processed. It is preferable because it is possible.

Next, an embodiment using the emission spectrum intensity and wavelength of plasma as the physical quantity of plasma will be described as a second embodiment of the present invention with reference to FIG. Figure 3
FIG. 6 is an explanatory diagram showing a semiconductor process monitoring device according to a second embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals, and the description of common parts will be omitted.

In the second embodiment, as shown in FIG. 3, the emission spectrum intensity and wavelength of plasma are used as the physical quantity of plasma.

The emission spectrum of plasma is generated when active species are generated and extinguished, and the wavelength has a specific region depending on the active species.

Further, the semiconductor process monitoring apparatus is constituted by including an emission spectrum measuring instrument 4b having a function described later as a plasma physical quantity measuring instrument, instead of the impedance measuring instrument 4a in the first embodiment.

Here, the emission spectrum measuring instrument 4b comprises a light receiving section 42 for measuring the emission spectrum and emission intensity of plasma. The light receiving portion 42 is arranged in the chamber 1 in the direction of plasma generated between the pair of electrodes 7. The light receiving section 42 is connected to the main body of the emission spectrum measuring instrument 4b by a cable or the like.

The emission spectrum measuring instrument 4b is housed in a shielding case 5 made of a conductive material having an electromagnetic shielding property, as in the impedance measuring instrument 4a. As shown in FIG. Connect to earth.

With this configuration, the emission spectrum measuring instrument 4b is not affected by noise and the like.
Accurate impedance measurement is possible.

The semiconductor process monitoring method will be described below with respect to only the points to be used instead of the impedance measurement shown in the first embodiment.

First, the emission spectrum measuring instrument 4b measures and confirms whether the wavelength of the plasma received by the light receiving section 42 is that of the target etchant. Then, if the plasma is a desired etchant, the emission spectrum measuring instrument 4b uses one of the semiconductor substrates 8 to be subjected to the plasma processing as a sample, as in the first embodiment, and outputs the emission spectrum intensity, Plasma processing time,
The correlation with the thickness of the desired portion of the semiconductor substrate 8 is obtained in advance.

The emission spectrum measuring instrument 4b uses the correlation between the emission spectrum intensity obtained in advance, the plasma processing time, and the thickness of a desired portion of the semiconductor substrate 8,
The thickness of the oxide film 8b remaining under the opening 8d is calculated and monitored from the emission spectrum intensity actually subjected to the plasma processing and the processing time, and when the desired thickness of the oxide film 8b is achieved, the high frequency The application by the power supply 2 is terminated.

In the semiconductor process monitoring method and the semiconductor process monitoring apparatus, whether or not the desired plasma is confirmed by first measuring the wavelength, and the emission spectrum intensity and the plasma, which are the physical quantities of the plasma required for the plasma processing, are confirmed. By measuring the processing time, the correlation between the emission spectrum intensity, the plasma processing time, and the thickness of the desired portion of the semiconductor substrate 8 which have been obtained in advance is used to calculate the thickness of the desired portion of the semiconductor substrate 8. When the thickness of the semiconductor substrate 8 reaches a desired thickness, the plasma processing is terminated, but since the transparency of infrared rays and X-rays is not used, a complicated film (deposition Film) is formed on the semiconductor substrate 8, or a deposited film having a thickness that does not transmit infrared rays and X-rays is formed on the semiconductor substrate 8. Even if they are, the semiconductor substrate 8
It is possible to easily and nondestructively measure the film thickness and the like formed above.

Next, an embodiment using a charge amount corresponding to a change in plasma as a physical amount of plasma will be described as a third embodiment of the present invention with reference to FIG. Figure 4
It is explanatory drawing which shows the semiconductor process monitoring apparatus which concerns on 3rd Embodiment of this invention. The same parts as those in the first embodiment are designated by the same reference numerals, and the description of common parts will be omitted.

In the third embodiment, the semiconductor process monitoring apparatus is the chamber 1 shown in the first embodiment.
Between the impedance adjuster 3 and the impedance adjuster 3, and more specifically, the capacitor 43 is provided between the impedance adjuster 3 and the chamber 1 on the lower electrode 7 side on which the semiconductor substrate 8 is placed. In addition, it has a configuration including a charge amount measuring device 4c having a function described later as a plasma physical amount measuring device.

Further, in the semiconductor process monitoring method, in the first embodiment, the impedance of the plasma between the pair of electrodes 7 in the chamber 1 is measured, but in the third embodiment, the physical quantity of the plasma is measured. Instead of directly measuring, the charge amount measuring device 4c measures the voltage between the capacitors 43 by using a desired terminal, a cable, or the like, and the capacitor 43 is used as a physical property value corresponding to a change in plasma from this voltage value. The amount of charges stored in the semiconductor substrate 8 is calculated, and the thickness of the desired portion of the semiconductor substrate 8 is calculated using the correlation between the amount of charges and the thickness of the desired portion of the semiconductor substrate 8.

The charge measuring instrument 4c is housed in a shielding case 5 made of a conductive material having an electromagnetic shielding property, as in the impedance measuring instrument 4a. As shown in FIG. Connect to earth.

With this structure, the charge amount measuring device 4c can measure impedance accurately without being affected by noise or the like.

As the capacitor 43, for example, an electric field capacitor having a capacity of several μfarad is used.

The semiconductor process monitoring method will be described below with respect to only the points that are used instead of the impedance measurement shown in the first embodiment.

First, the charge amount measuring device 4c uses one of the semiconductor substrates 8 to be subjected to plasma processing as a sample, for example, and correlates the voltage between the capacitors 43 and the thickness of a desired portion of the semiconductor substrate 8. Is obtained in advance.

The charge amount measuring device 4c uses the correlation between the voltage between the capacitors 43 and the thickness of a desired portion of the semiconductor substrate 8 to determine the opening 8d from the voltage between the capacitors 43 when the plasma processing is actually performed. Oxide film 8b remaining underneath
Is calculated and monitored, and when the desired thickness of the oxide film 8b is realized, the application by the high frequency power supply 2 is terminated.

In the semiconductor process monitoring method and the semiconductor process monitoring apparatus, the semiconductor substrate 8 and the physical property value corresponding to the physical quantity of the plasma required for the plasma processing, such as the amount of charge between the capacitors 43.
Of the semiconductor substrate 8 using the correlation with the thickness of the desired portion of
The thickness of the desired portion of the semiconductor substrate 8 is calculated, and the plasma processing is terminated when the thickness of the semiconductor substrate 8 reaches the desired thickness. However, since the transparency of infrared rays, X-rays, etc. is not used, light scattering is a problem. When a complex film (deposited film) that extends over multiple layers is formed on the semiconductor substrate 8 or when a deposited film having a thickness that does not transmit infrared rays, X-rays, etc. is formed on the semiconductor substrate 8. The film thickness formed on the semiconductor substrate 8 can be easily measured nondestructively.

[0059]

As described above, in the semiconductor process monitoring method of the invention according to claim 1 of the present application, the physical quantity of the plasma during the plasma processing and the thickness or the variation of the thickness of the semiconductor substrate, which are obtained in advance, The correlation of is obtained in advance, the physical quantity of plasma during plasma processing is measured,
The thickness of the desired portion of the semiconductor substrate is calculated using this correlation, and the plasma treatment is terminated when the thickness of the semiconductor substrate reaches the desired thickness, but the transparency of infrared rays and X-rays is used as in the past. If a complicated film (deposited film) that extends over multiple layers, where light scattering is a problem, is formed on the semiconductor substrate, or if the deposited film has a thickness that does not transmit infrared rays, X-rays, etc. It has been possible to provide a semiconductor process monitoring method capable of easily and nondestructively measuring the film thickness and the like formed on a semiconductor substrate even when formed on a substrate. Further, since the film thickness formed on the semiconductor substrate is measured inline during the semiconductor process, it is possible to provide a semiconductor process monitoring method that does not need to interrupt the process and has good work efficiency.

Further, in the semiconductor process monitoring method according to the invention of claim 2, in the invention of claim 1, the physical quantity of plasma is easily measured by using the impedance of plasma as the physical quantity of plasma. There is an effect that can be.

Further, in the semiconductor process monitoring method of the invention according to claim 3, in the invention according to claim 1, by using at least the emission spectrum intensity and wavelength of plasma as the physical quantity of plasma, The physical quantity can be easily measured.

Further, in the semiconductor process monitoring apparatus of the invention according to claim 4, a chamber having a pair of electrodes therein, a high frequency power source for applying a high frequency voltage or high frequency power, and a high frequency power source It is equipped with an impedance adjuster that adjusts the impedance of the semiconductor substrate to match the characteristic impedance and optimize it when the impedance of the semiconductor substrate itself deviates from the characteristic impedance, and a plasma physical quantity measuring instrument that measures the physical quantity of plasma. A pair of electrodes and a high frequency power source are electrically connected to each other through an impedance adjuster, and a high frequency power source applies a high frequency voltage or a high frequency power between the pair of electrodes to generate plasma, and the plasma physical quantity measuring device 4 By measuring the physical quantity of plasma in the chamber according to claim 1 to claim 3, Since the amount of change in thickness or the amount of thickness of the semiconductor substrate provided on one of the pair of electrodes is calculated, it does not utilize the transparency of infrared rays and X-rays as in the conventional case, When a complex film (deposited film) that extends over multiple layers where scattering of light is a problem is formed on the semiconductor substrate, or when a deposited film having a thickness that does not transmit infrared rays or X-rays is formed on the semiconductor substrate Moreover, it has been possible to provide a semiconductor process monitoring device that can easily and nondestructively measure the film thickness and the like formed on a semiconductor substrate. In addition, since the film thickness formed on the semiconductor substrate is measured inline during the semiconductor process, it is possible to provide a semiconductor process monitoring device with good work efficiency without the need to interrupt the process.

Further, in the semiconductor process monitoring apparatus of the invention according to claim 5, in the invention according to claim 4, the plasma physical quantity measuring device is connected between a pair of electrodes provided in the chamber. Since the impedance measuring device is provided with a terminal for measuring the impedance of the plasma, the impedance of the plasma as a physical quantity of the plasma can be easily measured.

Further, in the semiconductor process monitoring apparatus of the invention according to claim 6, in the invention according to claim 4, the plasma physical quantity measuring device is configured to detect the plasma generated between the pair of electrodes provided in the chamber. Since it is an emission spectrum measuring instrument that measures the emission spectrum intensity and wavelength of plasma by including a light receiving unit that takes in the emission spectrum, it is possible to easily measure the emission spectrum intensity and wavelength as physical quantities of plasma. Play.

Further, in the semiconductor process monitoring apparatus of the invention according to claim 7, in the invention according to claim 4, a capacitor is provided between the chamber and the impedance adjuster, and the plasma physical quantity measuring device is a capacitor. Since this is a charge amount measuring device that has the function of measuring the voltage between them and calculating the amount of charge accumulated in the capacitor, it is possible to easily measure the amount of charge corresponding to changes in plasma as the physical amount of plasma. There is an effect that can be.

Further, in the semiconductor process monitoring apparatus of the invention according to claim 8, claims 4 to 7 are provided.
In any one of the inventions, the plasma physical quantity measuring instrument is housed in a shielding case formed of a conductive material having an electromagnetic shielding property, and the shielding case is connected to the ground to prevent the influence of noise or the like. This has the effect of enabling accurate measurement of the physical quantity of plasma without receiving it.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a semiconductor process monitoring apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic view and a cross-sectional view showing a semiconductor substrate according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a semiconductor process monitoring device according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a semiconductor process monitoring apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

1 process chamber 2 high frequency power supply 3 impedance adjuster 4 Plasma physical quantity measuring instrument 4a Impedance measuring instrument 4b spectrum measuring instrument 4c Electric charge meter 5 Shielding case 6 plasma 7 electrodes 8 Semiconductor substrate 8a Silicon wafer 8b oxide film 8c resist 8d opening 41 Measurement terminal 42 Light receiving part 43 capacitor 81 cells

Claims (8)

[Claims] 1. A semiconductor process monitoring method for processing a thickness of a semiconductor substrate using plasma, wherein a physical quantity of plasma required for plasma processing is correlated with a thickness of a semiconductor substrate to be processed or a variation in thickness. Is obtained in advance, when the semiconductor substrate is subjected to plasma processing, the physical quantity of plasma during the plasma processing is measured, and based on the correlation, the change amount or the thickness amount of the thickness of the semiconductor substrate is calculated. A method for monitoring a semiconductor process, characterized in that the plasma treatment is terminated when the thickness of the substrate reaches a desired thickness. 2. The semiconductor process monitoring method according to claim 1, wherein the physical quantity of the plasma is impedance of the plasma. 3. The semiconductor process monitoring method according to claim 1, wherein the physical quantity of the plasma includes at least the emission spectrum intensity and wavelength of the plasma. 4. A chamber having a pair of electrodes inside, a high frequency power source for applying a high frequency voltage or high frequency power, and a semiconductor substrate when the impedance of the semiconductor substrate itself deviates from the characteristic impedance of the high frequency power source. An impedance adjuster for adjusting the impedance of the substrate to match the characteristic impedance to optimize the impedance and a plasma physical quantity measuring instrument for measuring a physical quantity of plasma are provided, and the pair of electrodes and the high frequency power source are provided. An electrical connection is made via an impedance adjuster, a high-frequency voltage or a high-frequency power is applied between the pair of electrodes by the high-frequency power source to generate plasma, and the plasma physical quantity measuring device is used for the plasma physical quantity measuring device. The physical quantity of plasma in the chamber according to any one of 3 above is measured to measure the physical quantity of the pair of electrodes. Semiconductor process monitoring device and calculates the amount of change or the thickness of the thickness of the semiconductor substrate formed by providing on one electrode. 5. The plasma physical quantity measuring device includes a measuring terminal connected to each of the pair of electrodes, and a function of measuring an impedance of plasma generated between the pair of electrodes using the measuring terminal. The semiconductor process monitoring apparatus according to claim 4, which is an impedance measuring instrument including: 6. The plasma physical quantity measuring device comprises a light receiving section for taking in plasma light generated between the pair of electrodes, and an emission spectrum intensity of plasma generated between the pair of electrodes in the light receiving section. The semiconductor process monitoring device according to claim 4, which is an emission spectrum measuring instrument having a function of measuring a wavelength. 7. A capacitor is provided between the chamber and the impedance adjuster, and the plasma physical quantity measuring device has a function of measuring a voltage between the capacitors and calculating a charge amount accumulated in the capacitor. The semiconductor process monitoring apparatus according to claim 4, which is a charge amount measuring device formed by 8. The plasma physical quantity measuring device is housed in a shielding case made of a conductive material having an electromagnetic shielding property, and the shielding case is connected to the ground. The semiconductor process monitoring device as described in 1.