JP4845816B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus used for semiconductor manufacturing and a plasma processing method using the plasma processing apparatus.

  In the manufacturing process of a semiconductor device, plasma etching, plasma CVD, or plasma ashing using weakly ionized plasma is used. In order to improve the stability in the semiconductor manufacturing process, it is required to grasp the fluctuation of the radical composition and the change with time of the chamber wall during the plasma processing. In plasma processing, if there is a change in the composition in the plasma, there is a risk of causing a dimensional change in the etching shape. Therefore, it is extremely important to grasp the composition change in the plasma with the progress of the processing time. In addition, it is important not only to change with time but also to confirm that the desired plasma composition ratio is obtained when the process conditions such as the gas flow rate ratio and input power are positively changed. Furthermore, there is a need for a technique that suppresses fluctuations in plasma by providing feedback based on monitored values.

  On the other hand, with the progress of miniaturization of semiconductor manufacturing equipment, deposition is required due to demands such as reduction of resist consumption rate (improvement of selection ratio) during etching accompanying etching of resist thin films and supply of sufficient etchant inside high-aspect ratio holes. It is expected that processing gas with strong characteristics will be used more and more. However, when a process gas having a strong deposition property is used, deposits adhere to the vacuum chamber. When the deposits are peeled off from the side walls of the vacuum chamber, the deposits contaminate the semiconductor production line as foreign particles and cause a decrease in yield. For this reason, from the viewpoint of long-term stability, it is extremely important to always grasp the amount of deposited film in the vacuum chamber and determine the timing of sweeping out the deposit before peeling off from the side wall of the vacuum chamber.

  So far, ideas have been devised for measuring the variation of radical composition in plasma and for measuring deposits on the side walls of the vacuum chamber. For example, a method has been proposed in which a mass analyzer is installed in the subsequent stage of a filter and chemical species that pass through the filter are identified (see, for example, Patent Document 1). However, in the method of installing a mass spectrometer after the filter, the measurement method itself may affect the composition of the radical species observed, and it is installed in a mass production device from the viewpoint of cost and long-term stability. Therefore, it is difficult to measure continuously. In addition, when the filter is installed on the susceptor, not only chemical species but also ions pass through the filter, so the deposited film formed through the filter has a film thickness and composition change caused by ion irradiation. It will be affected. In addition, when a filter is installed on the side wall of the vacuum chamber and the amount of deposit deposited is measured from the decay of electrons and ion current from the plasma by an ion current measuring instrument, However, it is difficult to measure current and require maintenance, and is not intended to measure the film thickness or mass of a deposit.

  In addition, it has been proposed to detect the end point of cleaning by measuring the film thickness deposited in the vacuum chamber by a film thickness monitor using a vibrator (see, for example, Patent Document 2). According to this method, it is possible to measure the increase or decrease of the film thickness deposited in the vacuum chamber from the viewpoint of detecting the end point of cleaning, but it does not grasp the film quality of the deposit.

  Furthermore, there has been proposed a dry etching apparatus having a feedback function for monitoring the amount of CF-based polymer deposited that causes a change in conditions in the chamber of the dry etching apparatus and controlling the film thickness (for example, Patent Documents). However, since the film quality of the deposit is not taken into consideration, there is a problem that it is not possible to cope with miniaturization and improvement in dimensional accuracy that will be required more and more in the future. In addition, a means for measuring the state in the etching chamber based on light emission has been proposed (see, for example, Patent Document 4). However, even in a means for measuring radical change from light emission from plasma, measurement by light emission is difficult. It is difficult to grasp the change of certain radical species.

In any of the previous inventions described above, it is possible to measure the increase or decrease of the film thickness deposited in the vacuum chamber from the viewpoint of detecting the end point of cleaning, but the main focus is on the increase or decrease of the deposited film. However, it does not grasp the film quality of the deposit. Also, the method of feeding back from the measurement result of the deposited film thickness in the chamber does not take into account the quality of the deposited film, so it will not be possible to cope with further miniaturization and improved dimensional accuracy that will be required in the future. There is. Furthermore, even in the means for measuring radical change from light emission of plasma, it is difficult to grasp the change of radical species that are difficult to measure by light emission.
Japanese Patent Laid-Open No. 8-138887 JP 2000-293829 A JP-A-10-64886 JP 2002-367958 A

  The present invention addresses such a conventional situation and does not use a special measurement device or light emission from plasma, and directly measures radical species in plasma by separating them under actual plasma processing conditions. An object of the present invention is to provide a plasma processing apparatus capable of accurately grasping a change in condition in a vacuum chamber.

  The present invention includes a processing chamber, means for supplying a processing gas to the processing chamber, vacuum evacuation means for depressurizing the processing chamber, an object mounting table on which the object to be processed is placed, plasma generation means, In the plasma processing apparatus having a control system for controlling plasma processing, a plurality of film thickness monitors are installed on the side wall of the processing chamber, and each of the plurality of film thickness monitors has a hole diameter to depth ratio of 0 to 30. And a filter having fine pores with a specific aspect ratio within the range of, and a thin film thickness measuring means for measuring the thickness of the thin film or the mass of the deposit at the subsequent stage of each of the filters, the aspect ratios of the filters being different I did it.

  According to the present invention, in the above plasma processing apparatus, the thin film thickness measuring means measures the deposited film thickness or the deposited film thickness rate based on the vibration frequency of the crystal resonator or the amount of change thereof.

  According to the present invention, in the plasma processing apparatus, a glass substrate is placed after the filter having fine holes, and the film thickness deposited on the glass is measured by an optical method.

  According to the present invention, in the plasma processing apparatus, the control system is a control system for controlling the temperature of the thin film thickness measuring means and the filter having the fine holes.

  According to the present invention, in the above plasma processing apparatus, the control system is a control system that controls the potential of the thin film thickness measuring means and the filter having micropores.

In the plasma processing apparatus according to the present invention, the material of the filter member is any one of SUS, Si, SiC, SiO ₂ , Al ₂ O ₃ , and C.

  According to the present invention, in the plasma processing apparatus, the control system is a control system that controls processing gas supply conditions in accordance with film thickness information measured by a thin film thickness measuring means in the latter stage of the filter having micropores.

  According to the present invention, in the plasma processing apparatus, the control system is configured to control a plasma generation condition in the plasma generation unit according to film thickness information measured by the thin film thickness measurement unit downstream of the filter having micropores. did.

  According to the present invention, in the above plasma processing apparatus, the control system is configured to warn or notify the cleaning timing in the processing chamber according to the film thickness information measured by the thin film thickness measuring means downstream of the filter having micropores. did.

In the plasma processing method using the plasma processing apparatus according to the present invention, an insulating film used for etching is SiO ₂ , SiC, SiOC, SiOCH, SiN on a silicon substrate which is a target object using the plasma processing apparatus, Etching is performed on a single film mainly composed of any one of Si ₃ N ₄ or a multilayer film composed of two or more kinds of films.

The present invention relates to a plasma processing method using the above plasma processing apparatus, in a process in which a fluorocarbon-based gas is a main component of plasma source gas, SiO ₂ , SiC, SiOC, SiOCH, Etching is performed on a single film mainly composed of one of SiN and Si ₃ N ₄ or a multilayer film composed of two or more kinds of films.

  As described above, in the present invention, by measuring the film thickness deposited through a plurality of filters having different aspect ratios of micropores, radical species in the plasma are separated and directly measured during the etching process. Can do.

  According to the present invention, the yield can be improved in the semiconductor manufacturing process.

  Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic diagram of a film thickness monitor of the present invention. The film thickness monitor includes a filter 101 having fine holes, a crystal resonator 102 supported by the crystal resonator support 103, an introduction path 104 for supplying a temperature control medium to the crystal resonator support 103, and a communication line 105. And a DC bias power source 106 for applying a bias voltage to the crystal resonator support 103 is connected.

  A crystal resonator 102 for measuring the film thickness or mass is installed at the subsequent stage of the filter 101 having fine holes. For the filter 101, a value (aspect ratio) obtained by dividing the thickness H of the filter by the hole diameter D of the fine hole is selected so that the composition of the adhering radical can be separated using the difference in the adhesion coefficient of radicals in the plasma. To do. The crystal unit 102 is connected to an oscillation circuit, a power source, a communication line, and the like, and can monitor the vibration frequency from the outside of the vacuum chamber via the communication line 105.

  The filter 101 is not directly fixed to the crystal unit 102 but is bonded to the crystal unit support 103 so that the oscillation frequency of the crystal unit 102 is not affected. Further, in order to avoid the accumulation of radicals that reach without passing through the filter 101, it is desirable that the distance L between the filter 101 and the support 103 is as small as possible. Furthermore, it is desirable that the filter 101 and the crystal resonator support 103 are in electrical contact as well as physical contact.

  A temperature control medium flow path is provided inside the crystal resonator support 103, and the temperature control medium such as florinate can flow through the introduction path 104. It is possible to control the temperature. Needless to say, the temperature control medium flowing in the flow path may be water, air, or the like. Further, in order to raise the temperature of the crystal resonator support 103, the crystal resonator support 103 itself may be heated by a heater. Furthermore, it is of course possible to control the temperature of heating or cooling of the crystal resonator support 103 itself by using a Peltier element. Of course, by controlling the temperature of the crystal resonator support 103 as described above, the temperature of the filter 101 in close contact with the crystal resonator support 103 can also be controlled simultaneously.

  Since the deposition coefficient of the deposition radical depends on the temperature, the radical species reaching the crystal unit 102 and the amount of deposition can be controlled by controlling the temperature of the filter 101. Further, a DC bias voltage can be applied from the DC bias power source 106 to the crystal resonator support 103 and the filter 101. In particular, by applying a positive bias to the crystal resonator support 103 and the filter 102, it is possible to reduce positive ions incident on the filter 102 from the plasma. This makes it possible to measure the deposited film of radicals while minimizing the influence of positive ion incidence. Further, if a negative bias is applied by changing the polarity of the DC bias voltage from the DC bias power supply 106, the incidence of negative ions can be suppressed.

  FIG. 2 shows an embodiment in which the present invention is applied to a plasma processing apparatus which is assumed to be used mainly in an etching process. The plasma processing apparatus includes a processing chamber 201, an antenna 203, a processing object mounting table 204 for mounting a processing object 202 and a focus ring 210, an electrostatic chuck electrode 205, a high frequency power source 206, A matching unit 207, an exhaust unit 208, a shower plate 209, and a film thickness monitor 211 are provided.

  An antenna 203 for electromagnetic wave radiation is installed in the processing chamber 201. A high frequency power source 206 for plasma generation is connected to the antenna 203 via a matching unit 207. A shower plate 209 is installed under the antenna, and a processing gas is introduced into the processing chamber 201 through a gas hole provided in the shower plate. Further, in order to depressurize the inside of the processing chamber 201 to a predetermined pressure, for example, an exhaust unit 208 such as a turbo molecular pump and a valve (not shown) for adjusting the inside of the processing chamber to a predetermined pressure value are provided. It is installed in the front stage. In the processing chamber 201, a processing object mounting table 204 for mounting the processing object 202 and the focus ring 210 is installed. On the mounting table, an electrostatic chuck electrode 205 for attracting the object to be processed 202 and a pusher pin (not shown) for lifting the object to be processed are installed. The film thickness monitor 211 is installed on the side wall inside the vacuum chamber.

Next, the principle of separating and measuring radical species in fluorocarbon plasma by using a plurality of filters 101 having different aspect ratios of micropores will be described. Depositionable radicals such as C, CF, CF ₂ , and CF ₃ are generated in the plasma using the fluorocarbon gas. In etching, the role of these radicals is very different. Here, it is possible to separate radical species by utilizing the fact that the target depositional radicals have different adhesion coefficients.

FIG. 3 shows the result of a simulation of the relationship between the hole aspect ratio and the deposition amount on the side wall of the hole based on the transport of sedimentary radicals. The aspect ratio is a value obtained by dividing the filter thickness H by the hole diameter D. Here, let us consider a radical in which the adhesion coefficient of carbon having a high adhesion probability is 0.1, and the adhesion coefficient of CF _{2 having} a low adhesion probability compared to carbon is 0.02.

From the simulation results shown in FIG. 3, the flux reaching the side wall decreases exponentially as the aspect ratio increases. In addition, radicals having a higher adhesion coefficient are deposited at a low aspect ratio portion, and the amount of radicals transported to the high aspect ratio portion is rapidly attenuated. On the other hand, radicals having a low adhesion coefficient are transported to a high aspect ratio portion without being greatly attenuated from the amount deposited in the low aspect ratio portion. Therefore, it is possible to mainly measure C having a high adhesion probability in the low aspect ratio portion, and it is possible to measure radicals such as CF ₂ having a high F content in the high aspect ratio portion.

  In addition, as shown in FIG. 3, when the aspect ratio is 30 or more, most of the radicals are deposited on the filter 101, and few radicals reach the bottom of the hole. It is desirable that the amount of radicals reaching the hole bottom is 30 or less, which is an amount that can be measured without being affected by errors.

  FIG. 4 shows an example in which a plurality of filters having different micropore aspect ratios are installed in fluorocarbon plasma, and a film deposited through the filters is analyzed. The filter had a hole with a diameter of 100 μm, and was used under three conditions: two types having a thickness of 1 mm and 2 mm, and no filter (with an aspect ratio of 0). X-ray photoelectron spectroscopy (XPS) was used for analysis of the deposited film. As a result, similarly to the result obtained by the simulation, the higher the aspect ratio of the micropores of the filter 101, the higher the ratio of fluorine contained in the deposited film, and the lower the aspect ratio, the percentage of carbon contained in the deposited film. Was confirmed to be high.

  Therefore, as shown in FIG. 5 which is a cross-sectional view of the processing chamber 201 as viewed from above, a plurality of film thickness monitors 211a to 211c shown in FIG. For each radical having a different F / C ratio, a filter having a different aspect ratio is placed on the front surface of the crystal resonator on which the radicals of the film thickness monitors 211a to 211c are deposited. It is also possible to measure the film thickness at the same time. The aspect ratio of the filter 101 to be used can take any value in the range of 0 to 50. Further, when the thickness of the filter 101 is constant, the aspect ratio can be changed by changing the diameter of the micropore. Furthermore, by adjusting the number of fine holes to make the opening area of the filter 101 constant, the effect of the difference in aspect ratio can be easily compared. However, even if the opening area of the filter 101 is different, it is needless to say that the same comparison can be made by normalizing the area. Further, since the film thickness monitor measures the amount of direct deposition without using light emission, it is possible to measure the amount of radical deposition (film thickness) even for radicals that do not emit light. In the example of FIG. 5, the film thickness monitor 211a uses a filter with an aspect ratio of 0 (no filter), the film thickness monitor 211b uses a filter with an aspect ratio of 10, and the film thickness monitor 211c has an aspect ratio of 20 This filter is used.

  In the above embodiment, the structure and mechanism of the film thickness monitor have been described. However, the present invention is not limited to this embodiment, and various improvements and modifications can be made without departing from the gist of the present invention. Of course, the present invention can also be applied.

  In the above-described embodiment, the plasma generation means has been described with respect to the means for generating plasma by applying high-frequency power different from that of the target object to the electrode disposed on the opposite side of the target object. A plasma processing apparatus characterized in that means for generating plasma by applying high-frequency power to a mounting table of an object to be processed or plasma generating means is inductively coupled or plasma is generated by the interaction of a magnetic field and a high-frequency electric field. Needless to say, the same effect can be obtained.

The specific process targeted for the above investigation is a process of forming a contact hole or the like in the insulating film, the gas system is C ₄ F ₆ / O ₂ / Ar = 30/30/500 ccm, and the pressure is about The measurement was performed under the conditions of 2 Pa, a semiconductor wafer set temperature of −20 ° C., and a wafer bias of about 1800 W. It goes without saying that the same effect can be obtained within the range where the gas type, gas flow rate, pressure, wafer set temperature and wafer bias do not deviate significantly from these conditions. Further, in a process in which a fluorocarbon-based gas is a main component of a plasma source gas, any one of SiO ₂ , SiC, SiOC, SiOCH, SiN, and Si ₃ N ₄ on a silicon substrate, which is an object to be processed, is a main raw material. Of course, the present invention can be applied to a process of etching the film. Note that the insulating film used for etching is an etching process of two or more types of multilayer structures of SiO ₂ , SiC, SiOC, SiOCH, SiN, and Si ₃ N ₄ on a silicon substrate that is an object to be processed using the plasma processing apparatus. Of course, the present invention can also be applied.

  Example 2 The structure of a film thickness monitor according to a second example of the present invention will be described with reference to FIG. In this example, optical measurement is used for the film thickness monitor. The film thickness monitor of this embodiment includes a filter 101, a window 301, and an optical sensor system 302. A window 301 in which radicals accumulate through the filter 101 is provided at the subsequent stage of the filter 101. Further, a conventionally used optical sensor system 302 is installed behind the window 301, and the film thickness is measured by plasma emission or reflection, absorption, interference, or the like of light emitted from the optical sensor system 302. It is possible. As the material of the window 301, it is desirable to use a material having a high light transmittance such as quartz. In addition, the surface of the window 301 is coated with a plasma-resistant protective film. By installing a plurality of filters 101 having different micropore aspect ratios on the front surface of the window 301 as in the first embodiment, it is possible to classify radical species in the fluorocarbon plasma.

  [Example 3] Using a plurality of the filters described in Example 1 or Example 2 (however, when the aspect ratio is 0, the filter is not used), the change in the deposition rate of each depositing radical is observed. A system for measuring fluctuations in the deposition radical species will be described.

  For example, consider a case where the radical composition during plasma treatment changes, the CF-based radical with a low F / C ratio having a large adhesion coefficient increases with time, and the CF-based radical with a small F / C ratio having a small adhesion coefficient decreases. .

  FIG. 7 shows how depositable radicals are deposited for each aspect ratio when a plurality of film thickness monitors are applied. FIG. 7A shows the state of the deposited film after Δt seconds. When the low aspect ratio filter fL101a is used, a CF radical having a small F and C ratio with a small adhesion coefficient can pass through the filter. Further, even a CF-based radical having a large adhesion coefficient and a low F / C ratio can pass through the filter when the low aspect ratio filter fL101a is used. Therefore, the deposited film formed by passing through the low aspect ratio filter fL101a is formed by depositing radicals having a high F / C ratio and a low F / C ratio. On the other hand, when the high aspect ratio filter fH101b is used, CF-type radicals having a large adhesion coefficient and a low F / C ratio can hardly pass through the filter, and the deposited film formed through the filter is: It consists mainly of CF radicals with a low F / C ratio and a small adhesion coefficient.

Now, let Δf seconds pass through the filter fL101a after the start of measurement, and let D _{fL_Δt be} the deposited film thickness, and _{let DfH_Δt} be the film thickness that has passed through the filter fH101b after Δt seconds, the respective deposition rates are as follows (1) Equation (2) and Equation (2) are obtained.
_{RfL_Δt} = _{DfL_Δt} / Δt (1)
_{RfH_Δt} = _{DfH_Δt} / Δt (2)

FIG. 7 (b) shows the state of the deposited film when Δt seconds have elapsed, that is, 2Δt seconds after the start of measurement. Here, if the total film thickness passing through the low aspect ratio filter fL101a after 2 Δt seconds is D _{fL — 2Δt} and the total film thickness passing through the high aspect ratio filter fH101b is D _{fH — 2Δt} , the deposition rate is The following equations (3) and (4) are obtained, respectively.
_{R fL_2Δt = (D fL_2Δt -D fL_Δt} ) / Δt ... (3)
_{R fH_2Δt = (D fH_2Δt -D fH_Δt} ) / Δt ... (4)

Here, when the number of CF radicals with a low F / C ratio with a large adhesion coefficient increases and the number of F-rich CF radicals with a small adhesion coefficient decreases with time, the deposition rate when a low aspect ratio filter is used is On the other hand, the deposition rate when a high aspect ratio filter is used is the following equation (6).
R _{fl — Δt} <R _{fl — 2Δt} (5)
R _{fh — Δt} > R _{fh — 2Δt} (6)

  FIG. 8 shows the relationship between the processing time and the deposited film thickness. When there is no change in the composition of the deposition radicals in the plasma, the deposition film thickness increases linearly with time and the deposition rate is constant (broken line) without depending on the aspect ratio of the filter. In contrast, when the radical composition during plasma treatment changes, CF radicals with a low F / C ratio with a large adhesion coefficient increase over time, and CF radicals with a low F / C ratio with a small adhesion coefficient decrease. The deposition rate of the deposited film passing through the low aspect ratio filter fL101a increases, whereas the deposition rate of the deposited film passing through the high aspect ratio filter fH101b decreases (solid line). As described above, by using a plurality of filters having different aspect ratios of the micropores, it is possible to separately measure changes in the deposition radicals having different F / C ratios.

  FIG. 9 shows the relationship between the rate of film thickness deposited through a plurality of filters having different aspect ratios of micropores and the compositional change of the deposition radicals in the plasma. This is the case where two types of filters with different aspect ratios of micropores are used, and the composition change of the deposition radicals in the plasma is judged by the combination of the deposition rate changes in the low aspect ratio filter and the high aspect ratio filter, respectively. be able to.

  Furthermore, high-accuracy processing can be performed by appropriately setting processing conditions based on the fluctuation of the depositing radicals obtained here. For example, an outline of a configuration of a plasma processing apparatus that performs feedback for suppressing dimensional variation will be described with reference to FIG. 2, the plasma processing apparatus includes a processing chamber 201, an antenna 203, a processing object mounting table 204 for mounting a processing object 202 and a focus ring 210, and an electrostatic chuck. An electrode 205, a high frequency power source 206, a matching unit 207, an exhaust unit 208, a shower plate 209, and a film thickness monitor 211 are included. Further, the plasma processing apparatus of this embodiment includes a gas flow rate control feedback unit 401a, a high frequency power source control feedback unit 401b, a wafer bias control feedback unit 401c, a gas controller 402, a gas pipe 403, and a wafer bias power source 404. And a matching unit 405 and an alarm device 406.

In this plasma apparatus, gas is supplied into the vacuum chamber through the gas pipe 403. The gas flow rate is controlled by the gas controller 402. Now, radical fluctuations in plasma are measured by a plurality of film thickness measurement systems 211 using a plurality of filters having different aspect ratios of micropores. Based on this measured value, a command can be given to the gas controller 402 so as to change the supply of the gas flow rate so as to suppress the dimensional variation in the processing of the substrate to be processed using the gas flow rate control feedback means 401a. For example, when C ₄ F ₆ , O ₂ , Ar is used for the gas system in the process of forming a contact hole or the like in the insulating film, a low F / C ratio is obtained when the deposition rate at a low aspect ratio increases with the progress of etching. As the radicals increase, the etching rate decreases and etch stop occurs. At this time, the gas flow rate control feedback means 401a is controlled to increase the oxygen flow rate to the gas controller 402 based on the measured value by the film thickness monitor 211. In addition to suppressing a decrease in etching rate and etching stop, it is a matter of course that various gas flow rates can be feedback controlled so that the ratio of radical species in plasma is constant.

  Further, the fluctuations of radicals in the plasma are measured by a plurality of film thickness monitors 211 using a plurality of filters having different aspect ratios of micropores, and the high-frequency power source control feedback means 401b is used to measure dimensions based on the measured values. The high frequency power supply 206 can be controlled so as to suppress the fluctuation, and the wafer bias power supply 404 can be controlled so as to suppress the dimensional fluctuation using the wafer bias control feedback means 401c. Although the control method for mainly suppressing the dimensional variation has been described here, it is needless to say that the processing shape can be controlled by positively controlling the deposition radical composition ratio in the plasma.

  Further, an alarm device 406 that issues a warning when the deposited film thickness measured by the film thickness monitor 211 exceeds a certain threshold value is connected. With this function, it is possible to know the timing of cleaning the inside of the chamber with oxygen plasma or the like and sweeping the inside of the chamber.

In the above embodiment, an example of SiO ₂ etching using C ₄ F ₆ is shown. However, in a process in which a fluorocarbon-based gas is a main component of a plasma source gas, SiO ₂ on a silicon substrate as an object to be processed, Of course, the present invention can be applied to a process of etching a film having any one of SiC, SiOC, SiOCH, SiN, and Si ₃ N ₄ as a main material. Note that the insulating film used for etching is an etching process of two or more types of multilayer structures of SiO ₂ , SiC, SiOC, SiOCH, SiN, and Si ₃ N ₄ on a silicon substrate that is an object to be processed using the plasma processing apparatus. Of course, the present invention can also be applied. Furthermore, it goes without saying that the same effect can be obtained even when a gas having a deposition property other than fluorocarbon is used.

Schematic which shows the structure of the film thickness monitor using the crystal oscillator based on 1st Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Schematic (sectional drawing) which shows the Example which applied this invention to the plasma processing apparatus. The figure which calculated | required the relationship between the aspect-ratio at the time of applying the film thickness monitor of this invention, and a deposited film thickness by simulation. The figure which shows the result of having analyzed the composition of the deposited film for demonstrating the effect of the film thickness monitor which concerns on 1st Embodiment of this invention. The figure explaining the apparatus structure at the time of applying the several film thickness monitor based on 1st Embodiment of this invention. Schematic which shows the structure of the film thickness monitor using the optical sensor system based on 2nd Embodiment of this invention. The graph which shows the time change of the deposited film thickness for every aspect ratio at the time of applying the several film thickness monitor based on 3rd Embodiment of this invention. The schematic diagram which shows a mode that the depositable radical for every aspect ratio at the time of applying the several film thickness monitor based on 3rd Embodiment of this invention accumulates. The table | surface for discriminating the change of the deposition radical composition ratio in plasma from the change of deposition rate using the several film thickness monitor based on 3rd Embodiment of this invention. Schematic (sectional drawing) which shows 3rd Embodiment which applied this invention to the plasma processing apparatus.

Explanation of symbols

D: Diameter of the hole in the filter 101,
H: the thickness of the filter 101,
L: the distance between the filter 101 and the support 103,
101 ... filter,
102: Crystal resonator,
103 ... support,
104 ... introduction path,
105 ... Communication line 106 ... DC bias power supply 201 ... Processing chamber,
202 ... object to be processed,
203 ... antenna,
204 ... the object mounting table,
205 ... Electrode for electrostatic chuck,
206 ... high frequency power supply,
207 ... matching device,
208: Exhaust means,
209 ... shower plate,
210: Focus ring,
211 ... Film thickness monitor,
211a: film thickness monitor using a filter with an aspect ratio of 0,
211b ... a film thickness monitor using a filter with an aspect ratio of 10,
211c: a film thickness monitor using a filter with an aspect ratio of 20,
301 ... Quartz window,
302 ... Optical sensor system,
401... Low aspect ratio filter fL,
402... High aspect ratio filter fH,
501a ... feedback means (gas flow rate control),
501b ... feedback means (high frequency power supply control),
501c ... feedback means (wafer bias control),
502 ... Gas controller,
503: Gas piping,
504: Wafer bias,
505 ... matching device,
505 ... Alarm device

Claims (5)

Controlling the processing chamber, means for supplying a processing gas to the processing chamber, evacuation means for depressurizing the processing chamber, a processing object mounting table for mounting the processing object, a plasma generating means, and plasma processing In a plasma processing apparatus having a control system for
A plurality of film thickness monitors are installed on the side wall of the processing chamber, and each of the plurality of film thickness monitors has a fine hole having a specific aspect ratio within a range of a hole diameter / depth ratio of 0 to 30. And a means for measuring the thickness of the thin film or the mass of the deposit at the subsequent stage of each of the filters, and the aspect ratios of the filters are different from each other. The plasma processing apparatus according to claim 1,
The plasma processing apparatus, wherein the thin film thickness measuring means measures a deposited film thickness or a deposited film thickness speed according to a vibration frequency of a crystal resonator or a change amount thereof. The plasma processing apparatus according to claim 1,
A plasma processing apparatus, wherein a window made of a material having a high light transmittance is placed behind the filter, and a film thickness deposited on the window is measured by an optical method. The plasma processing apparatus according to claim 1,
The plasma processing apparatus, wherein the control system is a control system for controlling the temperature of a thin film thickness measuring means and a filter having micropores. The plasma processing apparatus according to claim 1 or 2,
The plasma processing apparatus, wherein the control system is a control system for controlling a potential of a filter having a thin film thickness measuring means and fine holes.

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